Aymeric Dajnak

Limiao Shi

Gül Altınbaş Özpınar

Romaric Lenk

Nathalie Saffon-Merceron

Antoine Baceiredo

Tsuyoshi Kato

Thomas Müller

Eddy Maerten

Imine-Stabilized Silylium Ions: Synthesis, Structure and Application in Catalysis

Novel norbornene-based imine-stabilized silylium ions 2 have been synthesized via the simple reaction of sulfide-stabilized silylium ion 1 with carbonyl derivatives. Those silylium ions were fully characterized in solution and in the solid state by NMR spectroscopy and X-ray diffraction analysis as well as DFT calculations. Unlike the previously reported phosphine-stabilized silylium ion VI, behaving as a Lewis pair, calculations show that 2 have a strong Lewis acid character. Indeed, imine-stabilized silylium ions 2 are able to activate Si-H bonds and catalyzed the hydrosilylation of carbonyl derivatives under mild conditions.

Introduction

Since the isolation of the first stable free silylium ion I (Figure 1) by Reed and Lambert in 2002, 1 considerable effort has been devoted to studying the chemistry of silylium ions. 2 The accumulation of knowledge has allowed the development of stabilized systems that are easy to handle while preserving their unique reactivity and exceptional Lewis acidity. Of particular interest, the use of a weak Lewis base on the cationic silicon atom II has proven to be an excellent methodology 3 to find a good compromise between stability and reactivity, making those species useful as synthetic tools that can be applied in various transformations. 4 One of the best examples is the ferrocenium-stabilized silylium ion III, developed by Oestreich's group. 5 Indeed, this species is by far the most efficient catalyst to promote the Diels-Alder reaction in good yields at low temperature so far, even with challenging dienophile/diene combinations. 6 Interestingly, silylium ion III also smoothly catalyze in mild conditions the hydrosilylation reaction of carbonyl derivatives. 7 Another particularity of silylium ions lies in their potential to activate C-F bonds, due to the strong affinity between silicon and fluoride. Thus, catalysts of type IV and V are together with Ozerov's trialkylsilyliumcarborane systems efficient catalysts for hydrodefluorination reactions. 8,9 Obviously, the stability/reactivity balance of these species is strongly related to the choice of Lewis base ligand, which is crucial for their catalytic activity. We recently reported the synthesis of phosphine-and sulfide-stabilized silylium ions VI and 1 with a particular norbornene-based framework connecting the silylium ion and the donor ligand (Figure 1 and Scheme 1). 10 Interestingly, we have demonstrated that these two silylium ions exhibit very different reactivity toward methyl acrylate. Indeed, due to the moderate flexibility of the ligand framework and its strong nucleophilic character, despite its high stability, phosphinestabilized silylium ions VI behave as a Lewis pair and undergo ambiphilic type reactions leading to nine-membered heterocycles. 10a Similarly, VI reacts with benzaldehyde to give the carbonyl insertion product VII. In contrast, the sulfidestabilized silylium ion 1 acts as a simple Lewis acid due to a less nucleophilic character of sulfide ligand and efficiently catalyzes the Diels-Alder reaction with various olefins. 10b Here, we report that the sulfide-stabilized silylium ion 1 11 reacts with various carbonyl derivatives in a peculiar way, polar [4+2]cycloaddition, allowing to synthesize the original imine-

Results and discussion

Sulfide-stabilized silylium ion 1 readily reacts with benzaldehyde at room temperature to give the corresponding imine-stabilized silylium ion 2a (Scheme 1). Cation 2a was isolated as an air-sensitive yellow-orange powder (isolated yield: 44 %). 2a was obtained as a mixture of two diastereomers (75:25) as indicated by the presence of two sets of signals in the NMR spectra in the same ratio. In the 29 Si-NMR spectrum, two signals appear at higher field (12.3 / 7.4 ppm, major/minor products respectively) compared to the sulfide-stabilized silylium ion 1 (54.3 ppm). These chemical shifts are in good agreement with that of previously reported imine-stabilized silylium ions. 11a,12 In the 13 C-and the 1 H-NMR spectra, the two isomers of 2a exhibit two sets of singlet signals at 76.9 and 80.4 ppm and at 5.60 and 5.44 ppm, respectively corresponding to the former carbonyl group. Interestingly, similar reactivity of 1 was observed with different carbonyl compounds affording the corresponding imine-stabilized silylium ions 2b-e in good yields (Scheme 1). The less nucleophilic trifluoroacetophenone reacts more slowly with 1 This suggests that the reaction starts with carbonyl coordination on the cationic Si atom of 1. The following nucleophilic attack of enamine on the activated carbonyl carbon center completes the reaction. Indeed, the highly electron-poor perfluoroacetophenone [(CF3)(C6F5)C=O] is totally unreactive. All the 29 Si NMR signals of the different base-stabilized silylium ions 2a-e appear in the area of 5.5 -12.3 ppm. In 13 C NMR spectra, the chemical shift of Si-coordinated imine fragment can be found between 210.5 and 213.2 ppm, which is the typical region for iminium carbon atoms (or Lewis acid coordinated imines). 11a, 12 The structure of 2e was unambiguously confirmed by an Xray diffraction analysis (Figure 2). Yellow crystals were obtained in good yield (85 %) from a saturated chloroform solution. The molecular structure of 2e exhibits a relatively short C2-N1 bond [1.292(5) Å] and a planar environment (∑° = 359.7°) characteristic of the imine fragment. The N1-Si1 bond length is significantly elongated [1.839(3) Å] compared to that observed in 1 [1.737(2) Å], in agreement with a N->Si + dative character. 5), S1-C1 1.857(4), C1-C2 1.550( 6), C2-N1 1.292( 5), N1-C14 1.484( 5), S1-C8 1.804( 4), C26-C33 1.542( 6), C26-C27 1.559( 9), Si1-C39 1.823( 4), Si1-C40 1.838( 4 To gain more insight into the electronic structure of iminestabilized silylium ion 2, DFT calculations have been performed at the M062X/def-2TZVP level of theory. At this level, the optimized molecular structure of 2a, 2c and 2e are very similar and the structure of 2e is in good agreement with all relevant parameters experimentally observed (see Table S3). The results of the computations indicated that the formation of cation 2a is favoured by 80 kJ.mol -1 over the FLP-type carbonyl insertion product into the S-Si bond of silylium ion 1 (similar to the carbonyl insertion product VII, see also Table S2). The electrophilic center of cations 2 is the imine carbon atom. Similarly to the case of iminium-stabilized silylium ions described by Inoue, 12a the LUMO corresponds in all cases to the * orbital of the C=N double bond (See Figures 3 andS30). In addition, the electrostatic potential map of cation 2a shows the most positive potential around the imine group (Figure S31). The electronic structure of cations 2 is similar to those of typical stabilized silyl cations such as V and VI. 2e, 8j, 10 Taking into account the This journal is © The Royal Society of Chemistry 20xx J. Name., 2013,00,123Please do not adjust margins Please do not adjust margins steric shielding around the imine group, we suggest that the Lewis acidity of cations 2 arises from reaction of nucleophiles at the silicon center. The Lewis acidity of 2 is high as they are able to activate even Si-H bonds. 14 Indeed, H/D exchange between two deuterated/nondeuterated silanes (Et3Si-D/PhMe2H) in the presence of 10 mol% of 2 was evidenced either at 60 °C or at room temperature (Figure 4).

After 12 h at 60 °C in presence of 10 mol% of 2a, the reaction attains the equilibrium with a thermodynamic ratio (38 : 62) of Et3SiD/Et3SiH (or PhMe2SiH/Et3SiH). Even with a large excess of silane and a prolongated heating time, NMR data of catalyst 2 remain unchanged.

Of particular interest, the equilibrium is achieved at room temperature in less than 2 h with 2c, which demonstrates that the Lewis acid character of 2 is strongly related to the nature of substituents on the carbon atom next to the oxygen and can be easily modulated just by changing the carbonyl derivative used. Silylium ion 2a also efficiently catalyzes the hydrosilylation and allylsilylation of benzaldehyde with triethylsilane and allyltrimethylsilane respectively. Indeed, in presence of 2 or 10 mol% of 2a at room temperature, both reactions are quantitative in 15 min (isolated yield: 92 % and 99 % respectively, Scheme 2). The same results were obtained in the presence of a proton sponge (2,6-di-tert-butylpyridine), excluding a Brønsted acid catalysis due to a possible hydrolysis of 2a.

Scheme 2. Hydrosilylation and allylsilylation of benzaldehyde catalyzed by 2a.

Then the potential catalytic activity of silylium ions 2 in hydrosilylation of ketones has been evaluated (Table 1). For this purpose, we have started this study with the hydrosilylation of acetophenone in the presence of triethylsilane using different catalysts 2a-e (10 mol%) in order to evaluate the influence of catalyst substituents. The hydrosilylation in the presence of 2a (10 mol%) as catalyst at room temperature results in a quasi-full conversion of acetophenone in 4 hours affording two products, the silylated alcohol A and ethylbenzene B which is the result of the reaction of A with a second equivalent of silane, in the proportion of 87:10 (Table 1, entry 2). This full deoxygenation reaction is often observed when hydrosilylation is promoted by silylium ions. 15 A prolongated reaction time slowly increases the proportion of B (A : B = 74 : 26 in 29 h, Table 1, entry 3). Catalysts 2a, 2b, 2d and 2e, respectively with H/Ph, CH3/Ph, Et/Et and Ph/Ph substituents, present similar catalytic activities, leading to quasi-full conversions (95 % to 99 %) after 4 h with similar A : B proportions (74 : 14 to 87 : 10, Table 1, entries 2, 5, 11 and15). [START_REF]Reaction with catalyst 2b was also performed at 0°C to favor selectivity toward the silylated alcohol A without success (51 % conv. after 24 h[END_REF] In contrast, in the case of catalyst 2c with an electronwithdrawing CF3 substituent, the consumption rate of acetophenone is similar but the reduction of the silylated alcohol is much faster since 51 % of B is already formed when all acetophenone is consumed in 4 h (Table 1, entry 9). A full deoxygenation takes place in less than 29 h (Table 1,Entry 9). Therefore, considering the catalytic activity, we decided then to check the scope of the reaction with different carbonyl substrates using catalyst 2c with CF3/Ph substituents (Table 2). In contrast to the case of acetophenone (Table 1, entry 9), hydrosilylation reactions of trifluoroacetophenone and diethylketone using catalyst 2c (10 mol%, at room temperature) are selective and afford the hydrosilylated alcohol C as single 2012,00,123This journal is © The Royal Society of Chemistry 20xx

4 | J. Name.,
Please do not adjust margins Please do not adjust margins product (Table 2, entries 3 and 5). However, despite the clean and rapid reaction with the trifluoroacetophenone (full conversion in 7 h, Table 2, entry 3) the hydrosilylation of diethylketone is sluggish and leads to low conversion even after prolonged reaction time (43 % in 72 h, Table 2, entry 5) probably due to the decomposition of catalyst during the reaction. Contrary to these selective reactions, in the case of more reactive benzophenone, the reaction is not selective any more. Indeed, a full conversion of benzophenone is obtained in 2 h, leading to a 58 : 41 mixture of the corresponding silylated alcohol C and D (Table 2,entry 6). In 4 h, silylated alcohol C is fully converted into diphenylmethane together with hexaethyldisiloxane (Table 2, entry 7).

Conclusions

In conclusion, the imine-stabilized silylium ions 2, which can be easily obtained by simple reaction between the sulfidestabilized-silylium ion 1 and carbonyl derivatives, were found to be strong Lewis acids able of activating Si-H bonds and effectively catalyzing the hydrosilylation and allylsilylation of carbonyl derivatives. Because of the simplicity of the synthesis, derivatization of 2 is particularly easy and its Lewis acidity can be tuned just by changing the carbonyl derivative employed. Efforts are currently underway to expand the diversity of catalytic applications of 2.

Experimental

General Procedures. All manipulations were performed under an inert atmosphere of argon by using standard Schlenk techniques or high-pressure NMR tube techniques. Dry and oxygen-free solvents were used. 1 H, 11 B, 13 C, 19 F and 29 Si NMR spectra were recorded on Brucker Avance II 300 MHz, Avance III HD 400 MHz and Avance I and II 500 MHz spectrometers. Chemical shifts are expressed in parts per million with residual solvent signals as internal reference ( 1 H, 29 Si and 13 C{ 1 H}). 19 F chemical shifts were reported in ppm relative to CFCl3. The following abbreviations and their combinations are used: br, broad; s, singlet; d, doublet; t, triplet; q, quartet; m, multiplet. 1 H and 13 C resonance signals were attributed by means of 2D COSY, HSQC and HMBC experiments. The sulfide-stabilized silylium ion 1 was synthesized as previously reported. ref All commercially available reagents were used after drying and/or distillation in proper conditions.

Synthesis of 2a:

To a solution of 1 (150 mg, 0.13 mmol) in benzene (2.0 mL) was added benzaldehyde (13.7 µL, 0.13 mmol). Reaction mixture was stirred for two hours and two phases were formed, the upper phase was removed and the lower phase washed twice with benzene (0.3 mL). Lower phase was dried under vacuum to obtained the adduct 2a as a yelloworange powder (71.6 mg, 44 %). M.p. = 74 °C (Decomposition).

Major isomer (75 %): 1 H NMR (500 MHz, CD2Cl2): = 0.48 (s, 3H, Si-CH3), 1.17 (s, 3H, Si-CH3), 1.28 (d, 3 JH-H = 6.8 Hz, 3H, CH3iPr), 1.31 (d, 3 JH-H = 6.6 Hz, 3H, CH3iPr), 1.40 (d,3 JHH = 6.8 Hz,3H,CH3iPr),1.42 (d,3 JH-H = 6.6 Hz, 3H, CH3iPr), 1.83-1.65 (m, 1H, CH2), 2.17-1.86 (m, 3H, 3 CH2), 2.43-2.31 (m, 2H, 2 CH2), 2.47 (sept, 3 JH-H = 6.6 Hz, 1H, CHiPr), 2.99-2.85 (sept, 1H, CHiPr overlapped by signals of minor isomer), 3.34-3.27 (m, 2H, 2 CHbridgehead), 5.60 (s, 1H, CHO), 6.39-6.33 (m, 2H, CHPhCHO), 7.01-6.97 (m, 2H, CHPhCHO), 7.13-7.06 (m, 1H, CHPhCHO), 7.73-7.28 (m, 8H, 5 S(C6H5) and 3 CHdipp). 13 C NMR (126 MHz, CD2Cl2): δ = 0.2 (s, Si-CH3), 3.3 (s, Si-CH3), 24.5 (s, CH3iPr), 24.7 (s, CH3iPr), 25.4 (s, CH2), 25.8 (s, CH3iPr), 26.1 (s, CH3iPr), 26.7 (s, CH2), 28.6 (s, CHiPr), 29.7 (s, CHiPr), 40.6 (s, CH2), 43.6 (s, CHbridgehead), 49.3 (s, CHbridgehead), 68.5 (s, C-S), 76.9 (s, CH-O), 124.6 (br, i of BAr), 127.2 (s, CHdipp), 127.3 (s, CHdipp), 127.3 (s, CHPh), 128.2 (s, CHPh), 128.7 (s, CHPh), 129.2 (s, CHPh), 129.8 (s, CHPh), 130.3 (s, CHPh), 131.9 (s, CPh), 132.2 (s, CHdipp), 132.6 (s, N-CDipp), 135.5 (s, CPh), 135.5 (s, CPhCHO), 136.6 (br d, JC-F = 244.8 Hz, ArC-F), 138.6 (br d, JC-F = 244.8 Hz, ArC-F), 142.2 (s, CiPr), 143.8 (s, CiPr) (d,3 JHH = 6.6 Hz,3H,CH3iPr), 1.83-1.65 (m, 3H , CH2*), 2.17-1.86 (m, 2H , CH2*), 2.66 (sept, 3 JH-H = 6. 6 Hz, 1H, CHiPr), 2.99-2.85 (m, 4H, 2 CHbridgehead + CHiPr + 1H CH2*), 5.44 (s, 1H, CHO), 7.14-7.06 (m, 1H, CHPhCHO*),7.73-7.28 (m, 12H, all Ar* signal excepted for 1H CHPhCHO). 13 C NMR (126 MHz, CD2Cl2): δ = 0.8 (s, Si-CH3), 4.8 (s, Si-CH3), 24.6 (s, CH3iPr), 24.7 (s, CH3iPr), 24.7 (s, CH3iPr), 25.0 (s, CH3iPr), 25.2 (s, CH2), 25.9 (s, CH3iPr), 27.6 (s, CH2), 28.8 (s, CHiPr), 29.1 (s, CHiPr), 38.3 (s, CH2), 44.8 (s, CHbridgehead), 46.6 (s, CHbridgehead) Hydrosilylation of acetophenone: In a J. Young NMR tube, to 2a-2e (10 mol%) was added a solution of CD2Cl2 containing acetophenone (0.025 mmol), triethylsilane (0.053 mmol) and hexamethylbenzene as internal standard (0.0041 mmol). Reaction was monitored by 1 H NMR (relaxation time D1 = 10 sec). Conversions and selectivities were determined by 1 H NMR analysis of the crude samples.

Hydrosilylation of benzaldehyde: In a J. Young NMR tube, to a solution of 2a (2.0 mol%) in CD2Cl2 was added benzaldehyde (0.41 mmol, 41.8 µL) and triethylsilane (0.41 mmol, 47.6 µL) successively. NMR was realized 15 minutes after and full conversion was observed.

Allylation of benzaldehyde: In a J. Young NMR tube, to a solution of 2a (10 mol%) in CD2Cl2 was added benzaldehyde (0.082 mmol, 8.37 µL) and allylsilane (0.082 mmol, 13.0 µL) successively. NMR was realized 15 minutes after and full conversion was observed.

Figure 1 .

 1 Figure 1. Free silylium ion I and Lewis base-stabilized silylium ions II-VII.

Scheme 1 .

 1 Scheme 1. Synthesis of sulfide-stabilized silylium ions 2.

Figure 2 .

 2 Figure 2. Molecular structure of cationic part of imine-stabilized silylium borate 2e. Thermal ellipsoids represent 30 % probability. H and disordered atoms, counterion [B(C6F5)4] -and solvent molecule were omitted for clarity. Selected bond lengths [Å] and angles [°]: N1-Si1 1.839(3), Si1-O1 1.614(3), C26-O1 1.428(5), S1-C1 1.857(4), C1-C2 1.550(6), C2-N1 1.292(5), N1-C14 1.484(5), S1-C8 1.804(4), C26-C33 1.542(6), C26-C27 1.559(9), Si1-C39 1.823(4), Si1-C40 1.838(4); N1-Si1-O1 99.8(1), Si1-O1-C26 135.4(2), C26-C1-C2 111.6(3), C1-C2-N1 124.3(4), C2-N1-Si1 120.0(3), O1-C26-C1 105.8(3), C2-N1-C14 120.9(3), C14-N1-Si1 118.8(2), O1-Si1-C39 111.8(2), O1-Si1-C40 112.4(2).

  Figure 2. Molecular structure of cationic part of imine-stabilized silylium borate 2e. Thermal ellipsoids represent 30 % probability. H and disordered atoms, counterion [B(C6F5)4] -and solvent molecule were omitted for clarity. Selected bond lengths [Å] and angles [°]: N1-Si1 1.839(3), Si1-O1 1.614(3), C26-O1 1.428(5), S1-C1 1.857(4), C1-C2 1.550(6), C2-N1 1.292(5), N1-C14 1.484(5), S1-C8 1.804(4), C26-C33 1.542(6), C26-C27 1.559(9), Si1-C39 1.823(4), Si1-C40 1.838(4); N1-Si1-O1 99.8(1), Si1-O1-C26 135.4(2), C26-C1-C2 111.6(3), C1-C2-N1 124.3(4), C2-N1-Si1 120.0(3), O1-C26-C1 105.8(3), C2-N1-C14 120.9(3), C14-N1-Si1 118.8(2), O1-Si1-C39 111.8(2), O1-Si1-C40 112.4(2).

Figure 3 .

 3 Figure 3. Optimized molecular structure of cation 2a and calculated surface diagram of its LUMO (E = -4.24 eV, isodensity value: 0.04).

Figure 4 .

 4 Figure 4. H/D exchange between Et3SiD and PhMe2SiH catalyzed by 2. a) Time to achieve the 38 : 62 ratio of Et3SiD/Et3SiH. b) Determined by 1 H-NMR monitoring of PhMe2SiH/Et3SiH.

  , 148.5 (br d, JC-F = 241.3 Hz, ArC-F), 212.0 (s, N-C). 19 F NMR (471 MHz, CD2Cl2): δ = -167.6 (t, JFF = 19.2 Hz, m of ArC-F), -163.7 (t, JFF = 20.4 Hz, p of ArC-F), -133.1 (br, o of ArC-F). 11 B NMR (160 MHz, CD2Cl2): δ = -16.7 (s, BAr4). 29 Si NMR (99 MHz, CD2Cl2): δ = 12.3 (s, Si-CH3). Minor isomer (25 %): All signals marked with * are overlapped by signals of the major isomer. 1 H NMR (500 MHz, CD2Cl2): δ = 0.62 (s, 3H, Si-CH3), 1.00 (d, 3 JH-H = 6.7 Hz, 3H, CH3iPr), 1.25-1.21 (m, 1H, CH2*), 1.26 (d, 3H, CH3iPr*), 1.33 (s, 3H, Si-CH3*), 1.40 (d, 3H, CH3iPr*), 1.48

  4 (s, N-CDipp), 133.5 (s, CHPh), 136.6 (br d, JC-F = 244.5 Hz, ArC-F), 138.7 (br d, JC-F = 244.5 Hz, ArC-F), 140.5 (s, CPh), 141.9 (s, CPh), 142.2 (s, CiPr), 143.7 (s, CiPr), 148.5 (br d, JC-F = 240.5 Hz, ArC-F), 213.2 (s, N-C). 19 F NMR (471 MHz, CD2Cl2): δ = -167.5 (t, JFF = 19.2 Hz, m of ArC-F), -163.7 (t, JFF = 20.4 Hz, p of ArC-F), -133.0 (br, o of ArC-F). 11 B NMR (160 MHz, CD2Cl2): δ = -16.6 (s, BAr). 29 Si NMR (99 MHz, CD2Cl2): δ = 5.5 (s, Si-CH3). Scrambling H/D reaction: In a J. Young NMR tube, to a solution of 2a or 2c (10 mol%) in CD2Cl2 was added D1-triethylsilane (0.082 mmol, 13.1 µL) and dimethylphenylsilane (0.082 mmol, 12.6 µL) successively. Exchange reactions were monitored by 1 H NMR at different temperature (relaxation time D1 = 10 sec).

Table 1 .

 1 Hydrosilylation of acetophenone using triethylsilane catalyzed by imine-silylium ions 2a-2e.

	Entry a	Catalyst (10 mol%)	R	R'	Time (h)	Conv. (%) b	A c	B c
	1				2	61	52	4
	2	2a	H	Ph	4	97	87	10
	3				29	99	74	21
	4				2	48	40	4
	5	2b	CH3	Ph	4	99	87	10
	6				29	99	68	32
	7				2	76	43	30
	8	2c	CF3	Ph	4	99	43	51
	9				29	99	0	99
	10				2	85	74	7
	11	2d	Et	Et	3	95	78	11
	12				25	99	67	25
	13				2	52	34	14
	14	2e	Ph	Ph	4	95	75	14
	15				23	99	61	28
	a Reactions were carried out by using 0.25 mmol of acetophenone, triethylsilane
	(2.1 equiv, 0.53 mmol) and 10 mol% of 2 in 1 mL of CD2Cl2 in presence of 0.041
	mmol of hexamethylbenzene used as internal standard. b Conversions were
	determined by 1 H NMR analysis following acetophenone consumption compared
	to hexamethylbenzene (D1 = 10 sec). c Formation of products A and/or B were
	determined by 1 H NMR analysis of the crude compared to hexamethylbenzene (D1
	= 10 sec).

Table 2 .

 2 Hydrosilylation of ketones using triethylsilane with iminesilylium ion 2c.

	Entry a	R 1	R 2	Time (h)	Conv. (%) b	C c	D c
	1			2	13	13	0
	2	Ph	CF3	4	67	67	0
	3			7	99	99	0
	4 5	Et	Et	2 72	4 43	4 43	0 0
	6 7	Ph	Ph	2 4	99 99	58 0	41 99
	a Reactions were carried out by using 0.25 mmol of carbonyl derivative,
	triethylsilane (2.1 equiv, 0.53 mmol) and 10 mol% of 2c in 1 mL of CD2Cl2 in
	presence of 0.041 mmol of hexamethylbenzene used as internal standard. b
	Conversions were determined by 1 H NMR analysis following acetophenone
	consumption compared to hexamethylbenzene (D1 = 10 sec).

C

Formation of products C and/or D were determined by 1 H NMR analysis of the crude compared to hexamethylbenzene (D1 = 10 sec).

  , 68.8 (s, C-S), 80.4 (s, CH-O), 124.6 (br, i of BAr), 127.2 (s, CHdipp), 127.2 (s, CHdipp), 128.1(s, CHPh), 129.2 (s, CHPh), 130.4 (s, CHPh), 131.1 (s, CHPh), 132.1 (s, , ArC-F), 212.9 (s, N-C). 19 F NMR (471 MHz, CD2Cl2): δ = -167.6 (t, JFF = 19.2 Hz, m of ArC-F), -163.7 (t, JFF = 20.4 Hz, p of ArC-F), -133.1 (br, o of ArC-F). 11 B NMR (160 MHz, CD2Cl2): δ = -16.7 (s, BAr). 29 Si NMR (99 MHz, CD2Cl2): δ = 6.4 (s, Si-CH3).

	Synthesis of 2e: To a solution of 1 (300.0 mg, 0.27 mmol) in benzene
	(2.0 mL) was added benzophenone (4.91 mg, 0.27 mmol). Reaction
	mixture was stirred for 2 h and precipitate was formed, solvent was
	removed by filtration and the solid washed twice with benzene (0.5
	mL). Solid was dried under vacuum to obtained the adduct 2e as a
	yellow powder (295.0 mg, 85 %). Crystals were obtained from a
	chloroform solution at -30 °C. M.p. = 70 °C (Decomposition).
	1 H NMR (500 MHz, CD2Cl2): δ = 0.77 (d, 3 JH-H = 6.5 Hz, 3H, CH3iPr),
	0.78 (s, 3H, Si-CH3), 1.26 (d, 3 JH-H = 6.7 Hz, 3H, CH3iPr), 1.33 (d, 3 JH-H =
	6.5 Hz, 4H, CH3iPr + CH2), 1.36 (s, 3H, Si-CH3), 1.37 (d, 3 JH-H = 6.7 Hz,
	3H, CH3iPr), 2.20-1.95 (m, 4H, CH2), 2.24 (sept, 3 JH-H = 6.5 Hz, 1H,
	CHiPr), 2.84-2.75 (m, 1H, CH2), 2.93 (br, 1H, CHbridgehead), 3.10 (sept,
	3 JH-H = 6.7 Hz, 1H, CHiPr), 4.08 (br, 1H, CHbridgehead), 7.06-6.93 (m, 6H,
	CHPh), 7.18 (m, 1H, CHPh), 7.75-7.34 (m, 10H, CHPh). 13 C NMR (126
	MHz, CD2Cl2): δ = 1.2 (s, Si-CH3), 5.8 (s, Si-CH3), 24.6 (s, CH3iPr), 24.9
	(s, CH3iPr), 24.9 (s, CH3iPr), 25.8 (s, CH3iPr), 27.1 (s, CH2), 28.6 (s, CHiPr),
	28.6 (s, CHiPr), 29.2 (s, CH2), 40.6 (s, CH2), 45.8 (s, CHbridgehead), 47.1
	(s, CHbridgehead), 76.9 (s, C-S), 89.3 (s, CPh2), 124.4 (br, i of BAr), 127.0

6 | J. Name., 2012, 00, 1-3 This journal is © The Royal Society of Chemistry 20xx Please do not adjust margins Please do not adjust margins Hz(s, CHPh), 127.2 (s, CHdipp), 127.4 (s, CHdipp), 127.6 (s, CHPh), 128.4 (br, CHPh), 128.8 (s, CHPh), 128.9 (s, CHPh), 129.6 (s, CHPh), 129.6 (s, CHPh), 129.7 (s, CHPh), 131.0 (s, SCPh), 132.1 (s, CHdipp), 133.

Acknowledgements

The Agence Nationale de la Recherche (ANR-16-CE07-0018-01) and the Ministère de l'Enseignement Supérieur et de la Recherche are gratefully acknowledged for Ph.D. grant to A. D. The authors would like to thanks the CNRS and the Université de Toulouse, UPS for financial support. Dr. Gül Altınbaș Özpınar thanks the Philipp Schwartz Initiative of the Alexander von Humboldt Foundation for financial support. The computations were carried out at the HPC Cluster, CARL, located at the University of Oldenburg (Germany) and funded by the DFG through its Major Research Instrumentation Program (INST 184/108-1 FUGG) and the Ministry of Science and Culture (MWK) of the Lower Saxony State.

Notes and references

Author Contributions

Conceptualization: A.B., T.K., T.M., E.M.; Investigation: A.D., L.S., R.L., G.A.O. (computational); X-ray structural studies: N.S.-M.; Supervision : T.M., T.K., E.M.; Writing -original draft: A.D., T.K, T.M., E.M.; Writing -review & editing: All authors. All authors have read and agreed to the published version of the manuscript.

Conflicts of interest

There are no conflicts to declare.


Véronique Bellon-Maurel
email: veronique.belleon-maurel@inrae.fr

Isabelle Piot-Lepetit

Nina Lachia

Bruno Tisseyre

Digital Agriculture in Europe and in France: which organisations to boost adoption levels?

Keywords: Digital agriculture, Innovation ecosystems, Green deal, Farm-to-Fork, Innovation adoption, Innovation use, Digitalization, #DigitAg

This paper presents the way the digital transformation of the agricultural sector is implemented in Europe and in France. It describes main European and national strategies, the structuration of research and innovation initiatives, and the development of captivity building devoted to foster innovations and encourage adoption and use. More specifically the French research and innovation ecosystem on digital agriculture is described. The actors involved come from different organisations, such as research and higher educational institutes, government agencies, AgTech companies, farmer unions…, and work together by means of associations (e.g. Robagri), networks (e.g. RMT Naexus, DigiFermes, Fermes Leader), or living labs (e.g. Occitanum) on both digital technology assessment and co-design. Additionally, an important support is also devoted to capacity building (e.g. Le Mas numérique, Mobilab) and a better understanding of the drivers of adoption and use of digital technologies (e.g. FrOCDA). Among these various organisations, #DigitAg, the Digital Agriculture Convergence Lab, has been created to foster interdisciplinary research on digital agriculture. All these initiatives aim at creating digital technologies supporting the European Green Deal, Farm-to-Fork and Biodiversity strategies as well as the French orientation towards more agroecological practices for safer and more sustainable food systems. Even though this ecosystem is developing fast, the objective of encouraging the coevolution of both digital and green transformations is not without challenges that still need to be overcome, either through new research and innovations initiatives or new collaborations between the actors involved.

Introduction

The European Union (EU) is a world's leading agricultural power. Agriculture contributed to 1.3% to the EU-27's gross domestic product (GDP) in 2020. The member state (MS) contributing the most is France (18%), followed by Germany, Italy, Spain, the Netherlands, Poland, and Romania.

Together, these seven Member States account for over three quarters of the total EU agricultural production value. More than a half (58.6%) of the total output value of the EU's agricultural industry came from the 'big four,' namely France (€75.4 billion), Germany (€56.8 billion), Italy (€56.3 billion), and Spain (€52.9 billion). The EU agricultural annual income per worker has slightly fallen (-1.5%) in 2020 while remaining at an estimated rate of 27%, higher than the 2010 index level. About a half (52.8%) of the total output value of the EU's agricultural industry in 2020 came from crops (€217.5 billion), within which vegetables, horticultural plants, and cereals were the most valuable products. About two fifths (38.6 %) of this total output came from animals and animal products (€158.8 billion), the majority being provided by dairy products and pigs. Agricultural services (€20.2 billion) and related non-agricultural activities (€15.3 billion) contributed to the remaining 8.6 % (Eurostat Statistics Explained 2021).

However, the European agriculture is also facing challenges. On the one hand, it is subject to pressures induced by climate change and soil artificialization. Climate change requires crop adaptation and is the cause of extreme weather events that therefore requires in-depth risk management. Soil artificialization, i.e. the transformation of land into human habitats and infrastructures, is leading to a decrease in agricultural land areas in many EU regions. On the other hand, European consumers' expectations are shaping food markets, through health, animal welfare, climate change, and environmental concerns as well as convenience and affordability. For instance, in 2019, the EU consumers' most important factors influencing food purchases included cost, food safety, ethics, and beliefs (European Commission 2019a).

To face these various challenges, a real transformation of agriculture and, more globally, food systems is needed. This call for change is not only technical but also includes organizational, trade, and socio-economic transformations. The digital transformation, which can be seen throughout the food systems from 'farm to fork,' can clearly support a transformation towards safer and more sustainable food systems. In particular, it opens opportunities for digital agriculture to meet challenges such as: (i) The need to intensify production while productive land areas are decreasing and negative environmental impacts are reduced and positive environmental impacts generated;

(ii) Demands for detailed and real-time monitoring of the environmental impacts of production systems; (iii) The need to deal with additional uncertainties involved by climate change at both a global and local level; (iv) New demands for a shrinking, aging and female workforce; and (v) The need to address consumer demands for local and ethical products, including animal welfare.

Additionally, it becomes a high priority on political and scientific agendas to tackle these two transitions all together, i.e. the digitalization of agriculture and the transition towards safer and more sustainable food systems, in a systemic way while focusing on both their acceleration and monitoring.

The digitalization of agriculture stems from an exogenous dynamic. It uses information and communication technologies (ICT) and computational resources to capture, transmit and analyse data, in order to produce indicators, provide recommendations, or automate processes. This digital transformation started with precision agriculture and precision livestock around 1990, with the objective of specifically addressing plant and animal needs through the use of automatic observations. Nowadays, it has expanded to a much broader concept born around 2015, called 'digital agriculture,' which embraces both several spatial scales, going beyond the management of the fields to encompass the exploitation, territory, value chain..., and temporal scales, from seasonal to long-term agricultural and food management. Therefore, digital agriculture tackles more complexity and changes the way decisions are made, work is carried out, and value chains are European cloud and edge solutions. Indeed, the European Strategy for Data, adopted in February 2020, aims to establish a single market for data, ensuring Europe's global competitiveness. This means enabling data sharing as well as practical, fair, and clear rules on data access and use.

Besides, through the Data Governance Act of November 2020, the EU provides measures to increase trust in business-to-business data sharing and includes measures to facilitate the reuse of data. Moreover, digital innovation is also fostered by the European Digital Innovation Hubs (EDIH), a program covering all economic and institutional sectors, including agriculture. Between 2021 and 2027, €1.5 billion will be invested in the EDIH network, with a half coming from the 'Digital Europe Programme' and the remaining from national and regional funds, to support approximately 200 digital innovation hubs. The objective is to fill the gap between research on digital technologies and their implementation and deployment and to bring research outcomes to the market in five specific areas: supercomputing, artificial intelligence, cybersecurity, advanced digital skills, and ensuring the use of digital technologies across the economy, especially agriculture. This initiative is completed by the Connecting Europe Facility (CEF-Digital), supporting public and private investments in digital connectivity infrastructure (e.g. 5G, backbone networks, digital connectivity in transport and energy projects) up to €2 billion until 2027. Otherwise, the EU has created the European Innovation Partnerships (EIPs) to promote participatory innovations at local scale by gathering together main stakeholders. The group dedicated to agriculture, called EIP-Agri, is particularly interested in digitalisation.

Regarding agriculture and rural areas, the political commitment of the European MS to join forces on digitalization is shaped by the 'Declaration of cooperation on smart and sustainable digital future for European agriculture and rural areas,' signed in 2019. Moreover, one of the pillars of the EU Green Deal strategy is the Farm-to-Fork strategy, which sets the 2030 targets for sustainable food production and is really challenging and ambitious for the agricultural sector (European Commission 2020). Digital development and innovations are expected to play an important role in meeting those targets. Following these strategies, the Common Agricultural Policy (CAP) post-2020 is developed to foster a sustainable and competitive agricultural sector that can support the livelihoods of farmers and provide healthy and sustainable food for society, as well as vibrant rural areas. The New CAP aims to be a modernized policy, with a strong emphasis on results and performance and is structured around 9 specific objectives and a cross-cutting objective on digitization, knowledge, and innovation. The digital transformation of agriculture is a dedicated ambition of the CAP. The 'second pillar' of the CAP, named the European Agricultural Fund for Rural Development (EAFRD), includes €8 billion for the Next Generation EU program to help rural areas make the structural changes necessary to achieve the goals of the European Green Deal and digital transformation, i.e. to build a greener, more digital, and more resilient Europe. For implementing these new strategies, MS will have access to a portfolio of CAP tools they can include in their National CAP Strategic Plans to boost digitalization in agriculture and rural areas, e.g. advisory services, knowledge exchange, or investment support.

Thus, the EU has and continues to dedicate massive funding to the development of digital technologies aiming at supporting the transition towards safer and more sustainable food systems, as stated in its Green Deal strategy. The strength of these investments is, first, to encourage numerous projects focusing on the coevolution of the digital and green transformations of agriculture, through the development of a European research-innovation-infrastructure continuum and the creation of synergies among all the funded EU projects and strong European networks of research and innovation actors.

Although research and development (R&I) structures dedicated to digital agriculture are still scare in Europe, the EU supports the development of precision agriculture and digital agriculture through the funding of specific research programmes. The most significant indicator of this strategy is the amount of grants allocated by the European Commission (EC) on collaborative projects. For instance, the Horizon 2020 research programme has dedicated €118 million to 16 European projects related to digital agriculture (see Table 1).

Insert TABLE 1 around HERE European R&I initiatives in digital agriculture

To prepare rural areas and farmers to this ongoing and upcoming digital transformation, research initiatives on digital agriculture have been developed, mainly by research units already involved in precision agriculture or precision livestock. Most advanced initiatives structuring the digital agriculture ecosystems can be found in the Netherlands, the UK, and France.

In the Netherlands, the leadership in digital agriculture is insured by Wageningen University and

The French innovation ecosystem in digital agriculture

As often encountered worldwide, digital technologies suffer from a lack of adoption that may be due to: (i) technical issues, e.g. lack of relevance and suitability between the technologies developed and the real needs and/or constraints of users; (ii) lack of awareness and digital education; and (iii) lack of confidence, mainly due to broken promises about digital tool performances. The French ecosystem of innovation has been organized to tackle these issues through the development of specific organizations. These organizations are multi-partners and very often gather together research and higher education institutes, related to the Ministry of Agriculture, like INRAE or L'Institut Agro, agricultural technical institutes, and AgTech companies.

All these participants help strengthen the French ecosystem, showing complementarities, even with slightly different objectives, on testing digital technologies, demonstrating digital technologies, raising awareness and training farmers, fostering (open) innovation, but also through a better knowledge of the digital market by means of the mapping of main stakeholders or the diffusion of digital tools. Table 2 describes the most prominent organisations, their role, and the main targeted actors (farmers or AgTech companies).

Insert TABLE 2 around here

The organisation of the French ecosystem mainly focusses on three types of activities: (i) mapping the diffusion of digital agriculture in France; (ii) organizing and boosting the digital agriculture innovation ecosystem in France; and (iii), testing and demonstrating digital technologies in real conditions, at farm scale, to raise farmers and advisors' awareness.

Mapping the diffusion of digital technologies and services is really important. Indeed, reliable information about the adoption of Digital Agricultural Services (DAS) is essential for different stakeholders, such as: (i) service provider companies, by allowing an overview of the current uptake of digital tools and also helping design services that really correspond to current needs; (ii) academics and farmer's organisations, to define the most appropriate initial education and vocational training that can develop farmers and advisors' skills related to the use of digital tools; and (iii) regional or national institutions, helping them define strategies and regulations supporting the agricultural sector [START_REF] Tey | Factors influencing the adoption of precision agricultural technologies: a review for policy implications[END_REF].

For organizing and boosting the uptake of digital innovation in France, there is a need for reliable statistics on DAS adoption and use. To meet this need, the French Observation Centre of Digital Agriculture Adoption (FrOCDA) was created in 2016 by L'Institut Agro Montpellier, with the financial support of the AgroTIC Corporate Chair and #DigitAg (described below). To gain knowledge on the adoption and use of digital technologies in agriculture in France, FrOCDA is led by an operational team embedded in a large teaching and research network interacting with students as part of their curriculum. Besides, a strong collaboration is set up with private partners who select the digital technologies to be studied and evaluate the outcomes of the studies before their diffusion. The approach implemented by FrOCDA is a progressive one, based on the assumption that the successive studies, each one targeting a specific digital technology, should consolidate statistics on the state-of-adoption of digital technologies in France. Thus, every three months, a study is carried out on a specific digital technology with the aim of answering the following questions: What is the level of use of this solution in France? What are the associated agronomic applications? What are their specificities, especially barriers or drivers of adoption? The methodology (see Figure 1) first provides a comprehensive inventory of the main stakeholders and main challenges for the digital technology under scrutiny and then interviews are conducted with main stakeholders, crosschecked by available data. It allows to collect and consolidate consistent and relevant information, while minimizing the time spent on data collection.

Insert FIGURE 1 around HERE

Between 2017 and 2021, 10 studies were carried out focusing on the adoption and use in agriculture of the following digital technologies: remote sensing, smartphone applications, farm management information systems (FMIS), geophysical measurements and soil mapping, robotics, variable rate application technologies (fertilization, seeding, etc.), global navigation satellite system (GNSS), yield monitoring, and weather stations.

Another prominent organisation that encourages innovation in digital agriculture is a French innovation hub dedicated to the agro-food sector in the South-West of France, called AgriSudOuest innovation or ASOI. ASOI has put digital agriculture innovations as a high priority for more than 10 years. This innovation hub, certified by the French Government and recognized by the European Union, gathers together start-ups, private companies, research and higher education institutions, and public and private stakeholders supporting the economic development of the Occitanie and New Aquitaine regions. The ASOI's objective is to improve competitiveness through innovation, by fostering the encounter of all these actors and encouraging the creation of collaborative projects.

It also informs its members about the latest available technologies and helps innovative ideas emerge. Lastly, ASOI was the partner of a European H2020 project called DIVA (see table 1), aiming at supporting the emergence and development of new industrial DigiTech value chains in the agrofood, forestry, and environment sectors.

Capacity building is another essential lever facilitating the diffusion of digitalization by increasing 'digital readiness' [START_REF] De Carolis | A maturity model for assessing the digital readiness of manufacturing companies[END_REF] of the agricultural sector. Indeed, digital technologies are disruptive in agriculture, which means that specific capacities have to be built to support their development, encompassing the entire agricultural ecosystem, i.e. farmers and advisors as well as students who may become future managers of cooperatives, food supply chains, or machine and agricultural input providers. Thus, both long-term and sort-term capacity building is necessary. New capabilities and skills are needed in digital sciences, e.g. sensors, data science -data collection, analysis, and visualization -, information systems, interoperability, but also in humanities and social sciences (HSS), e.g. ergonomics, design, law on data usage and ownership, organizational management, and digital adoption and use. This means that higher-education needs to set up new interdisciplinary curricula with students developing double, even triple, competences, for instance, in agricultural sciences, digital sciences, and humanities. In France, a specific master curriculum, AgroTIC, has been running for almost 25 years by L'Institut Agro Montpellier and Bordeaux Sciences Agro, allowing students specialized in agronomy to get skills in digital and computer sciences. In the last four years, AgroTIC added new courses related to HSS into its curriculum, especially on data law and U-X design. Until now, in France, no 'mirror' process has been found elsewhere, i.e. Besides, the lack of confidence has also been identified as a cause of non-adoption of digital technologies. Creating technical and economic references on digital tools and services, testing them, and demonstrating their potential in real conditions are becoming more and more important to boost the uptake of digital technologies in agriculture.

In 2016, five French technical agricultural institutes (ITA) launched the 'Digifermes' network in which digital tools are tested and demonstrated to farmers. The Digifermes network is a partner of the H2020 European project NEFERTITI (see Table 1), devoted to the implementation of regional hubs of 'demo-farmers' dedicated to digital tools. Furthermore, the 'Fermes Leader' network was To tackle adoption and use issues, it is essential to raise awareness of farmers mainly through demonstrations and training (e.g. Le Mas Numérique; the Mobilab). This topic is of interest anywhere worldwide. However, it is rather difficult to export digital technologies, since the success of its implementation is very dependent on local conditions and users. Building references on digital technologies is thus essential and is also at the top of the EU Horizon Europe agenda. Besides, it is also important to understand the real impact of the setting of living labs devoted to smallholders with regard to their digital transformation in such a multi-challenged context, e.g. climate change, agroecology, food quality…, especially when dealing with agricultural sustainability [START_REF] Bronson | Moving toward Generalizability? A Scoping Review on Measuring the Impact of Living Labs[END_REF].

#DigitAg, the digital agriculture convergence lab

The French research ecosystem on digital agriculture started to get structured in 2016, after the publication of the report entitled 'Agriculture innovation 2025', made at the request of several

A snapshot on the deployment of digital tools in the French agriculture and the reconfiguration of food value chains in Europe

Adoption of digital technologies in the French agriculture.

Many studies worldwide have examined the current uptake of DSA and generally found that, except for GNSS guidance and related technologies (Lowenberg-Deboer and Erickson 2019), like sprayer boom control and seeder row shutoffs, adoption is generally low. Available studies, which provide reliable estimates of the implementation of digital agriculture by farmers, based on random sample methods, have mostly studied North-American and Australian farmers [START_REF] Lewellyn | Adoption of precision agriculture-related practices: status, opportunities and the role of farm advisors[END_REF][START_REF] Schimmelpfennig | Farm profits and adoption of precision agriculture[END_REF]). In Europe, uptake rates are less well studied and understood (DEFRA 2013;

Paustian and Theuvsen 2017).

In France, the annual Agrinautes survey (carried out by Web-Agri, Terre-net, la France Agricole)

gives a global overview of the digital involvement of web-connected farmers. In 2022, 46% of them were connected by obligation, 31%, by usefulness (i.e. to save time), and 23% were hyperconnected. Internet is available in 95% of the farms, but 5% of them only have a throughput lower than 512 kb/s. Smartphone penetration rate is now 80% within this category of web-connected farmers. In Table 3, the digital technologies, studied by FrOCDA, are ranked from the most to the least adopted ones. The outcomes are in accordance with studies on North America or other European countries. The most adopted digital technologies are those which provide an immediate perceived benefit (e.g. working comfort, ergonomics, etc.), that are easy to use and have a good interoperability with other equipment on farm. The use of GNSS for guidance or auto-steering is a perfect example of such a technology widely adopted, as well as smartphone applications and, to a lesser extent, weather data and weather stations. Other digital technologies are mainly adopted for regulatory purposes or to meet traceability requirements for marketing/business purposes. For instance, 75% of arable crop farms are predominantly equipped with farm management information system (FMIS) enforced by supply chain requirements or some remote sensing services are adopted to meet regulatory objectives related to the declaration of crop fertilisation plans.

Otherwise, digital technologies that are more complex to implement or for which an immediate return is less perceptible are clearly less adopted. It includes solutions for implementing variable rate application, whether at the plot or at the intra-plot level. Indeed, the adoption of these technologies requires overcoming technical barriers related to the interoperability of the farm's digital equipment with, for instance, FMIS, data service providers, GNSS, and agricultural machinery (e.g. tractor, variable rate application tool, etc.). In order to be operational, these technologies must be simultaneously updated, and likewise for the skills of the farmers, operators and/or advisors.

While these are major technical and human obstacles, direct benefits are sometimes difficult to evaluate, explaining why very few farmers currently adopt them.

Table 3 also highlights the difficulty of presenting the figures related to digital technology adoption in a homogeneous and synthetic manner. Indeed, for digital services which are accessed through annual subscription (e.g. remote sensing), adoption rates can be expressed as a percentage of subscribed area. When digital services are accessed through technologies purchased and implemented on farm and used for several years (e.g. GNSS, yield sensors, FMIS or weather stations), results are expressed as a percentage of farms currently equipped. In addition, some technologies require further details on the type of use, e.g. yield sensor, since it can be very different from one farm to another. For instance, FrOCDA revealed that even if the majority of new combines are equipped with yield sensors, only a few of equipped farmers use them to produce yield maps (~20%) and even fewer actually use them as a decision support system for variable rate applications (~5%). This shows that there is definitely a difference between adoption and use (Verdegem and De Marez 2011). Finally, the adoption is, of course, largely influenced by the characteristics of the farms, their digital maturity [START_REF] De Carolis | A maturity model for assessing the digital readiness of manufacturing companies[END_REF], and their links with upstream and downstream partners. FMIS is the best illustration of this. A majority of farms (~75%) with arable crops are equipped with traceability systems, due to the demand of their downstream partners for regulatory reasons, whereas practically none of the small farms involved in direct sales or short distribution circuits are equipped with such systems.

Insert TABLE 3 around HERE

Regarding the adoption and use of agricultural robots in France, results shows that they are mainly adopted, in 2018, by dairy farms with about 9,000 milking robots and 2,000 other robots (e.g. feeding, and stable cleaning robots), in nearly 10% of the French dairy farms. Those numbers have probably increased, since, in 2018, 70% of newly installed dairy farms chose to buy one or more milking robots. In breeding systems (bovine, caprine, or ovine dairy) about 2,000 robots are used to feed the livestock or clean buildings (scrapers and slurry vacuum cleaners). The adoption of robots in cropping systems, although a reality today, remains very limited with approximately 150 robots in 2018 (especially in vegetable cropping). These robots are mainly used for mechanical weeding with small autonomous weeders (e.g. Naio technologies). Numerous farms using these kinds of robots are vegetable organic farms (~100 robots). The study identified viticulture as the second robot adoption sector, just after dairy farms, with robots dedicated to mechanical weeding.

Digital technologies in the European Agri-food value chains

Digital innovations are also transforming agri-food value chains, by reshaping the way not only we produce, but also we supply, share and consume food. Benefits are expected in every aspect of our lives, ranging from more personalized and healthy diets to request for more transparency about the food we are offered, and more customized, local, and sustainable food productions. Data generated in value chains are important inputs for a better understanding of consumptions trends through the implementation of machine learning or data analytics. The way data are produced, shared, used, and re-used opens up to new challenges that need to be tackle in the coming years. Indeed, changes are fast and profound. They are mainly due to AgTech start-ups, which offer digital services that can be operated on smartphones, tablets, laptops, and other computers, while others are embodied in specific equipment [START_REF] Birner | Who drives the digital revolution in agriculture. A review of supply-side trends, players and challenges[END_REF]). However, digital technologies have not entered the various segments of agrifood value chains identically in Europe. For instance, in France, the production and retail/consumer segments are those where the larger number of startups are developing [START_REF] Florez | How do French agri-tech startups contribute to the sustainability of agri-food chains[END_REF]. In Germany, delivery services are where digital technologies are the most present. In the Netherland, start-ups are distributed all along the Agri-food Tech value chain due to a strong agrifood ecosystem, government incentives, and a network of universities, helping start-ups to look immediately for internationalization, as their local market is limited (DigitalFoodLab 2021).

In Europe, consumers are more and more concerned by the origin and quality of food and are looking to buy fresher, healthier, and more environment-friendly products. Digital technologies lay an important role in developing traceability of food and more transparency (El Hadad-Gauthier and Piot-Lepetit 2022). Start-ups developing blockchain-based applications promote food quality and create awareness on sustainable practices, in order to increase consumer trust and bring value to producers. Blockchain and e-certifications are also developed to facilitate international trade.

Digitalization can become a driver of upgrading on global value chains and help develop more into higher value-added activities (López González and Jouanjean 2017). E-commerce platforms enable producers to get access to different inputs, price comparisons, allowing cost reductions, or to locally connect to their consumers, therefore empowering local markets associated with fast delivery.

More and more digital technologies are also developed by start-ups with an objective of linking economic considerations with environmental or social ones. As pointed out by [START_REF] Liguori | Rising to the challenge: entrepreneurship ecosystems and SDG success[END_REF], innovative start-ups are nowadays looking for value opportunities in connection to the sustainable development goals. For instance, in France, more and more digital services address the segment of waste reductions on various segments of the agri-food value chains, trying to support the development of more circularity in production (e.g., Organix4 , a brokerage platform for trading agricultural wastes and by-products) and consumption processes (e.g., Togoodtogo app5 ).

Discussion

Digital agriculture, as the use of digital technologies in agricultural production from farm to fork, goes far beyond precision agriculture or precision livestock. Although digitalization in agriculture is still limited in France, except in the dairy sector, France is in the world top 6 countries regarding investments in AgriTech (including digital tech and biotech), with around €1 billion invested in 2021.

In 2021 France counts 250 AgriTech start-ups. Investments in AgTech in Europe have followed the world's trend, representing 8% of total investments, half being dedicated to food delivery and ebusiness (La Ferme Digitale 2022). One can expect this trend to keep going. Indeed, the demand for food of higher quality and nutritional contents is growing, jointly with a consumer concern about food sustainability, food origin, and production processes. Farmers are also facing the climate change challenges, with increased temperatures, changes in rainfall patterns, more frequent extreme weather events and reductions in water availability. This situation calls for new levers to support producers. Digitalization can be one of these levers. In a recent report commissioned by the French Ministries of Agriculture and the Economy, a qualitative survey puts forward that five out of the nine most impacting levers to accelerate innovation in agriculture and food value chains are linked to digital technologies: data collection, robotization and automation, traceability, process digitalization, and artificial intelligence (La Ferme Digitale 2022). However, even if the digitalization of agriculture and the food value chain is underway in Europe and France, numerous challenges still need to be overcome.

A first challenge is 'not to miss the target' of innovation. As stated by [START_REF] Cook | Embedding digital agriculture into sustainable Australian food systems: pathways and pitfalls to value creation[END_REF], the challenge is "more effective management processes enabled by digital agriculture, rather than the development of the technology itself." This means that technological development is not the most important part, and that the way digital technologies transforms processes has to be thoroughly studied. Furthermore, due to the pervasive character of data, digitalization not only transforms the specific part of the system where it is operating but also opens opportunities to trigger changes in other parts of it. Value can precisely be found in these indirect changes that could benefit farmers.

In Europe and in France, another conducive process, set high in the political agenda, is currently developing in agriculture, namely the agroecological transformation of agriculture. The deployment of these new production processes can be supported by the co-development of digital, green pathways, through the design of digital technologies specifically dedicated to the various forms of agroecology. To induce these transformative changes and this co-evolution, synergies need to be The second challenge is to set up the institutional support needed for shaping this digital transformation of agriculture and food value chains [START_REF] Cook | Embedding digital agriculture into sustainable Australian food systems: pathways and pitfalls to value creation[END_REF]. A first set of basic conditions can be considered as the minimum requirement for the use of digital technologies. It includes, for instance, technology availability, connectivity, affordability or ICT in education. The second set of incentives concerns enabling conditions, as factors facilitating the adoption of technologies and, among them, the development digital skills and an innovation culture (e.g. hackathons, incubators, accelerator programs). National digital strategies and regulations are another the driving forces behind digitalization as they create an enabling environment for competitive digital markets and eservices. For instance, the European Digital Strategy sets the objective of benefiting all (European citizens, business, etc.) and the environment, while at the same time improving data governance to mitigate negative side effects, to ensure that individuals, farmers and small businesses have the

  designed. More specifically, digital agriculture was made possible by the combined use of several new technical levers (Bellon-Maurel and Huyghe 2017): -Abundant, low cost, and on-field/on-animal data, issued from new data sources, like satellite imageries or connected objects (Internet of Things or IoT); -New capacities in artificial intelligence (AI), machine learning, and high performance computing, allowing new dimensional modelling; -New capacities related to enhanced connectivity between actors, including social media; and -Increased automation and robotization, including process controllers and autonomous robots. The objective of this paper is to describe the development status of digital agriculture in Europe and in France through the implementation of new strategies and regulations and the creation of organizations aiming at supporting the transformation of agriculture by means of the adoption of digital technologies. Then, some perspectives are given on the potential of the ongoing new ecosystem to impulse a real change regarding the use of digital technologies in agriculture. The R&I landscape of digital agriculture in Europe and France Political agendas contributing to digital agriculture in Europe The European digital agenda for the new decade (up to 2030) addresses the widespread, rapid, and extensive development of digital technologies and use. It focuses on creating secure digital spaces and services and regulating digital markets and large digital platforms, with the objective of strengthening Europe's digital sovereignty while, at the same time, contributing to the European goal of climate neutrality by 2050 (European Commission 2019b). The European strategy regarding digital agriculture is based on a multi-financial framework initiative, supporting research and innovation through the Horizon Europe programme together with a focus on the development and deployment of digital capacities in agriculture. Capacity development is implemented by means of different digital programmes, such as (i) the creation of a common European agricultural data space, facilitating the trustworthy sharing and pooling of agricultural data and aiming at increasing the economic and environmental performance of the agricultural sector; (ii) IA testing and experimentation facilities, to boost the uptake of trustworthy AI for the European agrifood sector; or (iii) Digital Innovation hubs, to provide technological expertise and experimentation facilities enabling the digital transformation of the agricultural sector. In the European Strategy for Data, the European Commission also supports the research and development, and large-scale deployment, of next-generation cloud infrastructure and services across the EU. These new cloud and edge capacities should be highly secure and completely interoperable and should offer open, multi-vendor cloud platforms and services. The objective here is to enable European data spaces and foster innovative data-sharing ecosystems based on

  Research (WUR), with a long-standing tradition on precision agriculture and social sciences dedicated to innovation. There are at least six academic chairs involved in digital agriculture development, focusing on Geo-information Science and Remote Sensing (GRS), Farm Technology (FTG), Mathematical and Statistical Methods (Biometris), Knowledge, Technology and Innovation (KTI), Information Technology (ITG), or Operations Research and Logistics (ORL). Following the creation of the Wageningen Data Competence Center (WDCC) in 2018, WUR made 'Data-driven and high-tech innovations' one of the five research programmes of its 2019-2022 strategic plan. Moreover, in 2021, WUR became the host of the activities of the former CTA, Technical Centre for Agricultural and Rural Cooperation, a joint international institution of the African, Caribbean, and Pacific States supported by the European Union, for 20 years after the Cotonou Agreement. Digitalization has been a focus of CTA for more than 8 years, with a ICT Updates Newsletter launched in 2013. In the UK, two out of the four AgriTech Centers launched in 2016 by Innovate UK are related to digital agriculture: Agri-EPI (Engineering, Precision and Innovation) and Agrimetrics. These centres gather government, academia, and industry resources to deliver research, development, demonstration, and training activities on precision agriculture and engineering. Agrimetrics has created a marketplace dedicated to agrifood data, the world's largest sourcing, management and monetization infrastructure of pre-linked and analysis-ready agricultural and food data.

  computer-science students getting skills in agricultural/biological sciences in order to become digital agriculture specialists. Regarding short-term capacity building, vocational training has been developed. Besides, in 2017, l'Institut Agro Montpellier and Bordeaux Sciences Agro created the AgroTIC Corporate Chair. Thus corporate chair, funded by the two agricultural schools, 27 companies, three technical agricultural institutes, and a research institute, aims at of creating collective intelligence around issues related to education, collaborative research, and the adoption of digital technologies in agriculture. The advantages of this public-private organization are: (i) the commercial neutrality, which is ensured by the diversity of a large number of companies; (ii) the academic legitimacy, which is gained by the presence of academics; (iii) the warranty to focus on high-stake technologies, by involving technical agricultural institutes; and (iv) the access to important information on sales, innovation, and adoption, insured by the involvement of AgTech and digital advisory companies. The AgroTIC corporate chair has been at the origin of the creation of two original training infrastructure: (i) the MobiLab, a truck with up-to-date digital technologies to train farmers where they are and also to carry out with them co-innovation initiatives and (ii) the French Observation Centre of Digital Agriculture Adoption (FrOCDA), already described above. The creation of innovative training and innovation actions is really important for fostering the uptake of digital technologies in agriculture. The MobiLab's activities include demos and self-construction of low-cost digital solutions technologies (e.g. sensors, sensor networks, connected objects), which helps farmers understand what is 'behind' the digital technology. The Mobilab is funded by the AgroTIC corporate chair, showing that, far from being afraid by the potential self-construction of sensors/automated systems by farmers, AgTech companies consider it as a training activity aiming at increasing farmers' confidence in digital tools. In 2020, the association of agricultural technical institutes (ACTA) launched the Naexus network, with the support of the French Ministry of Agriculture, to gather together a large number of French digital agriculture actors (54 in 2021), including research and higher education institutions, chambers of agriculture, technical agricultural centres, agro-machinery suppliers, farmer unions, AgTech companies, etc. The Naexus network provides to its members: (i) studies on new technologies; (ii) digital technology assessments; (iii) vocational training; and (iv) advisory services to support both digital and agroecological transformations.

  launched in 2017, by the InVivo cooperative group. It aims at evaluating the technical and economic performances of digital technologies, by testing them on farms with farmers. The Fermes Leader network also carries out training and awareness raising sessions with farmers. In 2021, the network rallies 29 cooperatives and 400 farms. Academics, like INRAE, are partners of this initiative, but are not involved in the setting and the exploitation of experimentations. In 2017, L'Institut Agro Montpellier has set up le Mas Numérique (the Digital Mediterranean Farm), supported by the AgroTIC Corporate Chair and #DigitAg (to be introduced below). In this unique educational and experimental farm, digital tools and solutions provided by 17 AgTech companies are used and tested by the technicians of L'Institut Agro Montpellier, not only to implement the farm's production activities but also to organise demonstrations and training, in both initial education and vocational training sessions. To tackle the numerous challenges the agricultural sector is facing, e.g. agroecology, climate change, local food systems…, the Living Lab (LL), called Occitanum 1 , was launched in 2020 (McPhee et al. 2021). Financially supported by the French 'Territories of Innovation' programme, Occitanum gathers together academics, farmers, agricultural organizations, and technical agricultural institutes. Its objective is to build a set of references on the multi-performance of digital technologies, in real conditions, of seven production sectors, such as livestock, arable crops, fruits, vegetables, wine, etc. Occitanum aims at developing new indicators on the environmental or the social benefits brought by digital technologies. In the 13 experimental sites, located in the Occitanie Region, a local animation is organized to bring out farmers' bottlenecks and needs for innovation and to address them by either identifying an existing digital technology that can solve the problem and evaluating it or setting up a consortium to design a new digital solution. In 2022, Occitanum became partner in the CODECS Horizon Europe project 2 .

French

  Ministries: Agriculture, Research and Innovation, and the Economy. Even though there exists a number of French research units involved in digital agriculture, the French research panorama on digital agriculture has been highly structured by #DigitAg (Figure2).Insert FIGURE 2 around HEREMain research teams, being part of the French ecosystem on digital agriculture, are most often, located within Agronomy Schools linked to the Ministry of Agriculture, covers numerous areas of expertise. For instance, ESA Angers has a research unit (LARESS) specialized in social and economic sciences, studying the impact of digital technologies on organizations and workforce in agriculture.In Dijon, the Agroecologie research unit has a team specialized in precision agriculture. The TSCF research unit in Clermont-Ferrand is at the heart of the robotics development for agriculture in France. It is where Robagri 3 , the association dedicated to agricultural robotics, was created, in collaboration with AXEMA, the agricultural machinery union. Robagri now comprises more than 60 members, including manufacturers, start-ups, and research units.Within this panorama, #DigitAg, the Digital Agriculture Convergence Lab, led by INRAE, was launched at the end of 2016 for 8 years with a competitive grant of €9.9 million from the French Government programme called 'Investment for the Future.' #DigitAg relies on a research-educationinnovation continuum and aims at building interdisciplinary research on the responsible development of digital agriculture in France, Europe, and Southern countries. Additionally, #DigitAg also supports higher initial and vocational educational programmes and innovation facilities managed together with AgTech companies and farmers. Nowadays, #DigitAg gathers together 16 public and private partners, 30 research units, and around 700 affiliated people. The #DigitAg convergence lab is organized following a matrix crossing disciplinary axes, in which researchers of the same scientific disciplines can interact and evolve together, and interdisciplinary challenges, in which different scientific disciplines are needed to address research questions (See Figure3).Insert Figure 3 aroundHERETo support research, #DigitAg funded a large set of relatively small projects, carried out through PhD theses, 18-month postdocs, and master internships, with the aim of encouraging agility, interactions, and community building. Indeed, each PhD and postdoc student has two supervisors coming out from two different scientific disciplines, positioning the students at the cross-roads of interdisciplinarity. Sixty percent of the funds allocated to #DigitAg have been allocated to those interdisciplinary projects. The remaining 40% is mainly devoted the scientific animation of the Convergence Lab, which relies on both local and international actions selected by means of internal calls and covering the following areas: internal seminars and workshops, researcher summer schools, hackathons, invitation of foreign scientists, researcher mobility abroad, international conferences, common research and education actions with African universities or international organizations (e.g. CGIAR). After five years of existence, the strategy implemented by #DigitAg has led to two major changes: the development and strengthening of (i) interdisciplinarity in research projects and (ii) capacity building. Interdisciplinarity is the foundation and the purpose of the creation of a Convergence lab. Within #DigitAg, three scientific communities are gathered together: (i) Science and Technology (ST); (ii) Life and Environmental Sciences (LES); and (iii) Humanities and Social Sciences (HSS). To encourage interdisciplinary networking, three processes have been created and implemented: (i) Interdisciplinary workshops, organized by the axis and challenge leaders, jointly with the direction of #DigitAg; (ii) The funding of PhD thesis and postdocs grants, co-supervised by researchers from two different disciplinary domains and located in two different #DigitAg research units; and (iii) The Executive Committee, an instance helping the #DigitAg direction in the design of its strategy and the selection of projects and their improvement through recommendations aiming at increasing interdisciplinary connections within the #DigitAg Convergence Lab. This committee is composed of 25 people from different disciplinary background and research units and comprises the leaders of the #DigitAg axes and challenges and the #DigitAg operating directors. The Executive Committee gathers four times a year, creating strong interrelationships among its members and acting as a powerful interdisciplinary driver. Consequently, interdisciplinarity in #DigitAg projects, around 56 PhD theses and 15 postdoctoral subjects, has grown all along the five years of #DigitAg existence. To demonstrate it, 'simple' and 'extended' interdisciplinary indexes applied to co-supervised PhD theses has been created. A PhD thesis is considered as dealing with 'simple' interdisciplinarity when the two supervisors are from the same scientific community (namely, ST, LES or HSS) and 'extended' interdisciplinarity when the two supervisors are from two different scientific communities. Between the first and the fifth PhD campaigns, the 'extended' interdisciplinary index increased by 50%, from 60% to 90%. However, fostering interdisciplinarity has also created significant indirect impacts, beyond PhD students. Indeed, in 2020, an internal survey showed that 80% of the #DigitAg research units have created collaborations with another #DigitAg research unit they had never collaborated with before. Besides, #DigitAg researchers were involved in interdisciplinary groups (80% of the participants) aiming at setting new research agendas on digital agriculture (Bellon-Maurel et al. 2022a) and pushing forward new directions for research, especially on responsible digital agriculture (Bellon-Maurel et al. 2022b).

  embedded in research and innovation programmes (Weber and Rohracher 2012), especially through new research directions as described in the INRIA-INRAE white book on 'Agriculture and digital technologies' (Bellon-Maurel et al. 2022a), based on the responsible research and innovation principles (Bellon-Maurel et al. 2022b).

  tools and means to decide what is done with their data. Besides, public interventions can also be necessary in some areas to develop a digital agriculture ecosystem conducive to innovation, allowing risk-taking, trust-based relationships between stakeholders, financial opportunities, professional services, and the emergence of appropriate skills. Especially, in France, this role has allocated to a large set of organizations, such as #DigitAg, Occitanum, RMT Naexus…, and initiatives, such as the French AgriTech launched by the Ministries of Agriculture and the Economy in 2021, with €215 million, or the 'Agroecology and Digital Technology' Priority Research and Equipment Program (PEPR) launched in 2022, with €65 million. The strength of this ecosystem is to be strongly connected and to cover all the steps of the research-training-innovation continuum. Verdegem P, De Marez L (2011) Rethinking determinants of ICT acceptance: towards an integrated and comprehensive overview. Technovation 31, 411-423.TABLES Table 1. Synthesis of the most important H2020 European projects dedicated to digital agriculture (from 2016 to 2020)

FIGURESFig. 1 .Fig. 2 .

 12 FIGURES

Fig. 1 .Fig. 2 .

 12 Fig. 1. The general framework of the FrOCDA methodology

Table 2 .

 2 The digital agriculture innovation ecosystem in France

Table 3 .

 3 Adoption of Digital agriculture services (except of robotics) in France, ranked from the most to the least adopted.

https://occitanum.fr/eng/

https://cordis.europa.eu/project/id/101060179

https://www.robagri.fr/en/

https://www.organix.suez.fr/

https://toogoodtogo.fr/fr/

Funding. This work has been supported by the French National Research Agency under the Investments for the Future Program, referred as ANR-16-CONV-0004, and the AgroTIC Chair, Montpellier.

Data Availability Support. As it is a review paper, and not a research paper, no data has been produced. So no data will be made available.


Julien Giry

President Macron's television announcement of "a fifty-day lockdown, at least" constituted a crucial step in the management of the pandemic in France. While Emmanuel Macron developed a new set of restrictions on civil liberties, his discourse, and the government's communication in general, was confusing for many French people because of the many contradictory injunctions formulated since the beginning of March. Combined with an existing suspicion among the population toward politicians and the media generally, and the rise of a new and unknown disease, this cacophony of communication opened a window of opportunity for alternative discourses and explanations for the pandemic, some of which were conspiratorial in nature.

With this in mind, I will first examine the sequence of communication at the beginning of the pandemic and its effect on conspiratorial theorizing in France. Next, I will present the content of Covid-19 conspiracy narratives that circulated in France, mainly on the internet, in comparison to those of previous epidemics: the 1889-90 influenza, the 1918-21 "Spanish" flu, AIDS since 1982, and the 2009 swine flu. Finally, I will tackle the political uses of those conspiracy theories by far-right activists on the internet, politicians from the smaller parties in the context of the 2022 presidential election, and during street demonstrations against de facto mandatory vaccination and the introduction of a Covid health certificate.

The Beginning of the Pandemic: Awkward Political Communication as an Opportunity for Conspiratorial Discourse

As I argued elsewhere (Giry 2022), the combination of three factors opened a window of opportunity for alternative modes of political and social regulation 14 COVID-19 CONSPIRACY THEORIES IN FRANCE

such as conspiracy theories. First, there was the development of a new coronavirus, for which the scientific community had not reached a consensus in understanding or treatment. Second, there was the long-established mistrust of politics and the media [START_REF] Blondiaux | De la démocratie en France. En finir avec les faux-semblants[END_REF][START_REF] Cheurfa | 2009-2019: La crise de la confiance politique[END_REF][START_REF] Kantar | Baromètre 2021 de la confiance des Français dans les media[END_REF]. Third, at a time that required strong, clear statements, French official communication had been contradictory and confusing since the very beginning of the pandemic, in March 2020. On March 3, for example, a government spokeswoman insisted that: "We won't close the schools. Even if stage 3 is reached, that is to say a pandemic that circulates all over the country, we won't stop the everyday life of France." President Macron, on March 5, said: "At this time, we all know that the pandemic is inexorable." Two days later, the French president, after attending a play in a theater, declared that, "There is no reason, except for vulnerable people, to change our habits and hobbies," while clusters were already reported in several parts of France (Oise, Val d'Oise, Haut-Rhin, Bas-Rhin, Morbihan, Corsica, etc.). On March 9, France banned rallies of more than 1,000 people, and on March 11, visits to retirement homes were suspended. The very same day, while visiting a grammar school, the minister of health told accompanying journalists, "Children do not constitute a vulnerable public. There is no reason to fear bringing them to school." Those words were confirmed the next morning by the minister of education -"We never thought to close schools" -while in the evening President Macron ordered a set of restrictions to combat "the most serious health crisis in one century," including school closures. During his statement, the president also called upon people to stay at home, except to vote in the municipal elections the following Sunday. On March 14, the then prime minister announced more restrictive measures, such as the closure at midnight of "all non-essential" public places. After a historical rate of abstention for municipal elections -55 percent -President Macron declared on March 16 that France was at "war" and announced "a fifty-day lockdown, at least." Under threat of fines or other punishment, "non-essential" travels were prohibited; "essential journeys" were subjected to self-authorization through an official form.

In addition to the uncertainty caused by the new virus itself (even including its name: le/la Covid-19, coronavirus, SARS-CoV-2, 2019-nCoV, "Chinese virus" etc.), these episodes illustrate the confusion and contradictions in government communication since the very beginning of the pandemic. Indeed, this contradictory and unclear messaging has been constantly repeated since then. Masks were deemed useless in March 2020, but then became imperative to wear in public in April; the idea of introducing a "health passport" was dismissed as pure fantasy in April 2020, only for Covid-19 health passes to be established in August (which became a "vaccine pass" in February 2022). Likewise, the quid pro quo concerning the suspension for a couple of days of the AstraZeneca vaccine in March 2021, all the while described as safe and beneficial according to the health authorities. It is no surprise that many French citizens, combined with a preexisting suspicion of the political class, doubted that the government could efficiently fight the Covid-19 pandemic [START_REF] Perrineau | La société française et la pandémie de la Covid-19[END_REF].

The combination of these aforementioned factors provided a "window of opportunity," that is, a sociopolitical configuration that favors the emergence and spreading of alternative modes of regulation and comprehension of the health crisis, such as conspiracy theories or medical populism.

Covid-19 Conspiracy Theories in France: New Wine in Old Bottles?

Generally speaking, conspiracy theories thrive in periods of crisis and social turmoil. A conspiracy theory is defined as "the conviction that a secret, omnipotent individual or group covertly controls the political and social order or some part thereof circulates solely on the margins of society" (Fenster 2008, 1). From a functionalist point of view [START_REF] Giry | A Specific Social Function of Rumors and Conspiracy Theories: Strengthening Community's Ties in Trouble Times. A Multilevel Analysis[END_REF], political entrepreneurs use conspiracy theories to offer concurrent, alternative, and determinist explanations, symbolically reassuring, of literally extraordinary events, like terrorist attacks, assassinations, natural catastrophes, or pandemics. I will now summarize the main conspiracy theories that have spread in France since the beginning of the Covid-19 pandemic and examine parallels with those that flourished in previous pandemics dating from the end of the nineteenth century.

Among the first concerns was the foreign origin of the virus. This process of othering is a common feature in times of pandemic: the flu was "Russian" in 1889-90, "Spanish" in 1918-21, and "Mexican" in 2009, while the contemporary virus is "Chinese." At the beginning of the pandemic, while most scientists argued in favor of the zoonotic origin of a new coronavirus that developed first in China, many alternative theories emerged on the French internet: a deliberate lab leak in Wuhan or a biochemical weapon 1 created on purpose by Israel or the United States. According to this line of thinking, Covid-19 is part of a conspiracy led by hostile foreign countries to destroy France for their own benefits. Alain Soral, a prominent French far-right conspiracy theorist and antisemitic activist, assumed that Israel and its "agents" like the-then Minister of Health Agnes Buzyn (or Buzyn-Lévi as he insisted on saying), Bill Gates, and George Soros, in association with "Big Pharma," were responsible for the spread of the virus. The same was true in 1918, when, after World War I, the newspaper L'Echo d'Alger claimed that the so-called Spanish flu was in fact a German vengeance plot: "This infection is spread by evil Boche chemists who have introduced their corrupted bacillus in cans, who have sprinkled it on fruits and vegetables" (quoted in Omari and Doucet 2020).

Pharma" and notably the Pasteur Institute were also accused of being responsible for the pandemic. The main accusation was that Covid-19 was created in labs to sell vaccines for huge profit. This thesis was supported not only by most of the well-known French conspiracist leaders (Soral, Cassen from Riposte Laïque, or Laibi a.k.a. Le Libre Penseur, etc.), the newly created "re-information" website Ré-info Covid [START_REF] Giry | Des vérités plurielles? Sciences et médiation au prisme des défiances et hésitations vaccinales en France[END_REF], but also YouTube influencers specializing in alternative medicine or new-age theories such as Silvano Trotta, Thierry Casasnovas, or Jean-Jacques Crevecoeur. In addition to those leading conspiracist

BOX 14.1 DIDIER RAOULT, A TYPICAL CASE OF "MEDICAL POPULISM"

Didier Raoult emerged into the public eye in February-March 2020 as a polarizing figure, loved or loathed. An advocate of hydroxychloroquine as a cure for Covid-19, the French microbiologist personifies the "medical populism" of the likes of Professors Even, Andrieu, and Venet in the beginning of the AIDS pandemic in the mid-1980s with the "cyclosporine affair" [START_REF] Dodier | L'espace de la recherche médicale[END_REF]). Medical populism consists of "a political style that constructs antagonistic relations between 'the people' whose lives have been put at risk by 'the establishment' " (Lasco and Curato 2019, 1), which takes advantage of the crisis, and the uncertainty it develops, to publicly advance, in terms of agenda-setting, heterodox/marginal positions in the medical field and the public sphere. Medical populism, then, is based on three cumulative criteria: (1) The call to the people, common sense, and righteousness in opposition to expert and established knowledge as well as medical, industrial ("Big Pharma"), or political elites considered to be corrupt and incompetent; (2) the urgency of strong and immediate action to contain the ongoing crisis in opposition to long-term medical research;

(3) the simplification, the dramatization, and the spectacularization of the crisis and its issues.

In this respect, even if Raoult does not overtly support conspiracy theories, it is not surprising that his positions are backed or exploited, in part at least, by conspiracist far-right activists. Indeed, medical populism and conspiracy theories share key features: the rejection of elites and institutions of regulation or socialization (media, government, public health agencies, etc.) on behalf of the supposedly true people; the denunciation of purported secret or unlawful interests (conflict of interest, corruption, "Big Pharma"); the advocacy of miraculous and cheap treatments in opposition to established knowledge (hydroxychloroquine, azithromycine, or ivermectine); and bypassing mainstream communication channels in favor of alternative ones and social media (YouTube, Twitter).

figures, people like the humorist Jean-Marie Bigard and the singer Francis Lalanne argued that the government had purposely banned cheap and efficient early cures such as hydroxychloroquine, ivermectin, or azithromycin (see Box 14.1). This "Big Pharma" conspiracy theory played a central part in a French internet blockbuster Hold-Up!. Viewed almost six million times, this features physicians, scholars, and well-known political personalities 2 who defend, like Plandemic in the Englishspeaking world, the idea that the Covid-19 pandemic was voluntarily (mis)led by the authorities to advance a Great Reset agenda, just like with AIDS in the

BOX 14.2 CONSPIRACY THEORIES IN FRANCE: A VERY BRIEF HISTORY

It is often argued that modern conspiracy theories in France started during the French Revolution [START_REF] Tackett | Conspiracy Obsession in a Time of Revolution: French Elites and the Origins of Terror, 1789-1792[END_REF][START_REF] Oberhauser | Freemasons, Illuminati and Jews: Conspiracy Theories and the French Revolution[END_REF], mostly through the writings of Abbé Barruel, who claimed that "in the French Revolution, everything, even down to the most frightful excesses, was foreseen, intended, contrived, determined, decided upon: everything was the effect of the most profound wickedness, since all had been prepared and brought about by men who alone held the threads of long-fomented conspiracies in the secret societies and who knew how to choose and hasten the moments most favorable for their plots" (quoted in Giry 2020). Those "men" according to Barruel have names: the "demagogues" (i.e., the philosophers of the Enlightenment), the "freemasons," and "a society even more secret," that is, those who John Robison famously mistakenly called the Illuminati.

As [START_REF] Leroy | Le mythe jésuite[END_REF] and Cubbit (1993) noticed, what would become known as the "Jesuit myth" was the culmination of a huge conspiratorial imaginary from the seventeenth to the nineteenth centuries. Accused of being a "mysterious Sanhedrin" aiming to topple France and destroy Catholicism, the Jesuits were typical figures of hatred, like the Knights Templar were the century before (Giry 2020).

From the nineteenth century to the end of the Vichy regime, Jews and freemasons were targeted in right-wing newspapers as the cause of France's decay. Maurras, for instance, developed the conspiracy theory of "four confederate states" he named "Anti-France, secretly acting in cahoots to take over the country: foreigners (les métèques), Protestants, freemasons, and Jews.

After World War II and the Holocaust, conspiracy theories in France were confined to covert far-right circles. It is only during the early 2000s, immediately after the 9/11 attacks, that they reappeared in the public sphere, first with the publication of Meyssan's 9/11: The Big Lie (L'effroyable imposture) in 2002 and, even more spectacularly, in 2015 after the jihadist attacks which gave birth to so many conspiracy theories. Since then, successive French governments have engaged in a struggle against conspiracy theories.

1980s. The video also claims that the New World Order agenda began with the introduction of liberticidal measures such as lockdowns or mask-wearing in public spaces. 3 Mask-wearing and "Big Pharma" conspiracy theories echo narratives that were circulating in 1898-90 when physicians and chemists (nicknamed "Potards") were accused of making scandalous profits and in 1919 when mask-wearing was presented as an unlawful assault on civil liberties [START_REF] Vagneron | Une presse influenzée? Le traitement journalistique de la pandémie de grippe 'russe' à Paris (1889-1890)[END_REF].

Another common feature in pandemic conspiracy theories is neophobia, that is, the incrimination of new technologies allegedly responsible for the disease or its cover-up: radio waves during the 1918 "Spanish" flu, 3G in the 2002-04 SARS epidemic, smartphones themselves during the 2009 H1N1 flu, and now 5G technology. Interestingly, the theory that 5G is responsible for the Covid-19 pandemic was first argued on January 20, 2020, by a prominent French conspiratorial website Les Moutons Enragés (The Angry Sheep) [START_REF] Bruns | Corona? 5G? or Both?': The Dynamics of COVID-19/5G Conspiracy Theories on Facebook[END_REF], even though 5G was not yet in use in France.

Another set of conspiracy theories arose in the public sphere, claiming that government officials were deliberately exaggerating the dangers of Covid-19. They were supported by activist groups such as Aude digitale (Digital Dawn), crank physicians like Christian Perronne or Louis Fouché (Ré-info Covid), and professional conspiracy theorists like Alain Soral, who famously promoted in France the "empty hospitals theory" that spread on Twitter through the hashtag "#Film-YourHospital." This theory is particularly interesting because it triggered conflicts among French conspiracists, notably between Alain Soral and his former sidekick Vincent Lapierre, founder of Le média pour tous (The Media for All). Lapierre, who tried to reposition himself during the Yellow Vest movement as a legitimate "citizen journalist," found here a new opportunity to condemn his former boss of antisemitism and conspiracism. In return, he was accused of "BFMization" (from BFM TV, a 24-hour mainstream information channel, claimed to be Israel-led in conspiratorial discourses) and bowing down before the Israeli lobby.

From the Internet to the Streets: "Anti-pass" Protests and Political Uses of Conspiracy Theories in the Context of the 2022 Presidential Election

Although Covid-19 conspiracy theories have mainly circulated on the internet, some far-right politicians pushed them in the public sphere: National Front leader Marine Le Pen -although supporting "freedom of vaccination" and against the Covid-safe ticket (CST) -or the far-right polemist Eric Zemmour -who proposed removing the CST -rejected Covid-19 conspiracy theories about 5G, Bill Gates, or biochemical weapons (while still supporting Great Replacement ones). Florian Philippot, former National Front deputy leader; Nicolas Dupont-Aignan, leader of the sovereigntist party Debout la France!; or François Asselineau, leader of Union Populaire pour la République support conspiracy theories about a forthcoming "health dictatorship" in which de facto mandatory vaccination and the introduction of a Covid-safe ticket (transformed in February 2022 into a "vaccine pass") play a decisive part. During the 2022 presidential election, those "little candidates," or outsiders, were trying to make political gains by adopting unconventional, not to say heterodox, and conspiratorial positions in the political field. Indeed, since the middle of 2020, Philippot has organized in Paris a weekly protest against "health dictatorship and for civil liberties." Step by step, other street protests developed throughout France, joined by leading conspiratorial and "anti-vax" figures like Pierre Cassen or Christine Tasin from Riposte Laïque, Richard Bourtry (ex-journalist of the new FranceSoir), 4 crank physicians like Louis Fouché and Alexandra Haurrion-Caude from Ré-info Covid with its self-proclaimed "independent scientific committee," and artists likes Jean-Marie Bigard and Francis Lalanne. Whereas more than 90 percent of the French population over the age of 12 is vaccinated, 5 and more than 60 percent of French people approved the introduction of the CST for public events, those "anti-pass" protests, while struggling to mobilize after September 2021, were evidence of the huge polarization of French society on the eve of the 2022 presidential election. President Macron's legitimacy is highly contested (and even more so after he declared he wanted to "piss-off" -emmerdernon-vaccinated people); the traditional right-wing candidate Valérie Pécresse is marginalized in the public debate; the left is divided, and the polls indicate that the far-right leader Marine Le Pen could qualify for the second round of the election.

Notes

A viral video posted on March

25, 2020, on Facebook by @laurentjlc assumed that the pandemic was already planned in 2018 and was revealed in a Korean series, My Secret Terrius (S. 1, E. 10), which referred to "a mutant coronavirus" used as "a biochemical weapon." See Fourneau and Pailleux 2020. 2 After the film was broadcast, some participants asked to be withdrawn, including former Minister of Foreign Affairs Philippe Douste-Blazy or the sociologist Monique Pinçon-Charlot. They alleged that the edit and general tone of the film did not fit with their own views or words. 3 The second part of the film, released on November 18, 2021, argued that the virus was manufactured on purpose by "Big Pharma." 4 FranceSoir, a highly conspiratorial website, should not be confused with the former daily newspaper France-Soir. 5 Accessed on November 22, 2021, https://covidtracker.fr/vaccintracker.