Brice Arrazat
email: arrazat@emse.fr

Vincent Mandrillon

Karim Inal

Maxime Vincent

Christophe Poulain

Microstructure evolution of gold thin films under spherical indentation for micro switches contact applications

Keywords: micro-switch reliability, EBSD, microstructure, nano-indentation, contact mechanics

RF MEMS (Radio Frequency Micro Electro Mechanical System) switches are promising devices but their gold-on-gold contacts, assimilated for this work to a sphere / plane contact, represent a major reliability issue. A first step towards failure mechanism understanding is the investigation of the contact metal microstructure evolution under static and cyclic loading. After static and cyclic loading of sputtered gold thin films under spherical indentation, high resolution Electron Back Scatter Diffraction (EBSD) is used to investigate contact area. Grain rotation against {111} fiber texture of 1 µm thick sputtered gold thin film is a signature of plastic deformation. Grain rotation is observed above 1.6 mN under static loading by a spherical diamond indenter with 50 µm tip radius. A heterogeneity in grain rotation is observed corresponding to a more important plastic deformation in the middle of the indent than at the edge. A 30° Grain rotation is observed for a half million mechanical cycles under 300 µN load by a spherical gold tip (20 µm radius) due to cyclic work hardening. The same test in hot switching mode induces a grain growth in the contact area. Therefore thermal effects occurring during hot switching are underlined.

Introduction

Regarding the large spectrum of telecommunication standards and demands of communicating objects, transceiver systems will be dynamically reconfigurable. The most common possibility by far consists in a switching matrix to direct the signal through a dedicated block. For that possibility, the Micro Electro Mechanical Systems (MEMS) switch is an attractive alternative to traditional FET (Field Effect Transistor) or pi-n diode switches in applications where microsecond-switching speed is sufficient. A MEMS switch is composed by a mobile part (bridge or beam) and a contact area of few µm² (flat or spherical bump) separated by an air gap (Figure 1). The mechanical movement obtained using electrostatic, magnetostatic, piezoelectric, or thermal actuation is necessary to close the switch. These components show much lower insertion loss and higher isolation than their competitors [START_REF] Rebeiz | Rf mems switches and switch circuits[END_REF].

Recent works on contact switch reliability revealed two primary failure mechanisms during cycling which are contact resistance increase and stiction [START_REF] Coutu | A comparison of micro-switch analytic, finite element, and experimental results[END_REF][START_REF] Coutu | Microswitches with sputtered au, aupd,au-on-aupt, and auptcu alloy electric contacts. Components and Packaging Technologies[END_REF]. Those mechanical degradations of contact are linked to contact material properties. Practically, gold is selected as the contact material due to low resistivity and low sensitivity to oxidation. But, gold's relative low hardness and low softening temperature seem to be the origin of contact degradation [START_REF] Coutu | A comparison of micro-switch analytic, finite element, and experimental results[END_REF][START_REF] Coutu | Microswitches with sputtered au, aupd,au-on-aupt, and auptcu alloy electric contacts. Components and Packaging Technologies[END_REF].

To solve this problem, several studies are dedicated to alternative contact materials [START_REF] Coutu | A comparison of micro-switch analytic, finite element, and experimental results[END_REF][START_REF] Coutu | Microswitches with sputtered au, aupd,au-on-aupt, and auptcu alloy electric contacts. Components and Packaging Technologies[END_REF][START_REF] Chen | Contact resistance study of noble metals and alloy films using a scanning probe microscope test station[END_REF]. Gold alloyed with platinum-group metals are preferentially considered. Significant results are obtained showing sevenfold lifetime increases [START_REF] Coutu | Microswitches with sputtered au, aupd,au-on-aupt, and auptcu alloy electric contacts. Components and Packaging Technologies[END_REF]. But the same failure mechanisms occur. To understand the mechanisms which are at the origin of contact degradation, some investigations on morphology integrity are performed. Yan et al [START_REF] Yan | Finite element analysis of the thermal characteristics of mems switches[END_REF] demonstrate that degradation area increases with current intensity increase (from 70 to 350 mA). Also, degradation area increases under mechanical cycling at a force of 200 μN as a function of the number of cycles and is linked to an increase in contact resistance [START_REF] Chen | Mechanical, thermal, and material influences on ohmic-contact-type mems switch operation[END_REF]. Gregori investigates the deformation in the contact area and shows that partial flattening of asperities and pile-up formation occur with actuation [START_REF] Gregori | The interrelation between adhesion, contact creep, and roughness on the life of gold contacts in radio-frequency microswitches[END_REF]. Curvature radius of asperities and mechanical properties (elasticity and hardness) of material are major parameters of adhesion force [START_REF] Duvivier | Time dependence investigation of the electrical resistance of Au / Au thin film micro contacts[END_REF] and the evolution of adhesion force could explain stiction mode of failure.

In this work, after static and cyclic loading of sputtered gold thin films under spherical indentation, high resolution Electron Back Scatter Diffraction (EBSD) is used to investigate contact area microstructural changes. Complementary Atomic Force Microscopy (AFM) topography characterization (pile-up, indent diameter, asperity curvature radius) of contact area is performed. Localized nanoindentation measurement of hardness evolution linked to observed structural changes is also performed.

Samples description

Sample consists of the following sputtered thin film stack deposited on a silicon substrate: 1µm of gold / 50 nm tungsten nitride diffusion barrier / 20 nm tungsten adhesion layer. The rms roughness of the investigated gold surface is 5 nm. The average peak-to-valley is 35 nm. The average curvature radius of asperities on gold thin film is 240 nm.

Recent studies [START_REF] Humphreys | Review grain and subgrain characterisation by electron backscatter diffraction[END_REF] have demonstrated the maturity of EBSD in field emission scanning electron microscope (FEGSEM). High spatial resolution is reached as small as 10 nm. Penetration depth is around 5 nm into gold thin films. Crystallographic texture and grain boundary rotation of surface are determined and quantified. A strong {111} fiber texture normal to the gold surface is exhibited with an average 90nm grain size.

A Nanoindenter XP from MTS instruments is used to determine mechanical properties of the gold thin film using the dynamic contact module (DCM) option using a Berkovich indenter tip. The continuous stiffness measurement (CSM) technique allows the measurement of dynamic stiffness continuously throughout the loading segment by superimposing a small dynamic oscillating displacement to the quasi-static force by means of a frequency-specific amplifier. The oscillation displacement was 1 nm, the frequency was 50 Hz and the strain rate was constant (0,05 s -1 ). The area function of the Berkovich tip was obtained by the indentations on fused silica in the range of 10-300 nm indentation depth, i.e. displacement as suggested by [START_REF] Pharr | Critical issues in making small-depth mechanical property measurements by nanoindentation with continuous stiffness measurement[END_REF]. A total of 64 indentations were conducted on gold thin film and the average values of 64 indentations are presented in Figure 9. At a depth of 150 nm, the hardness of the gold thin film is 1.6 GPa and the elastic modulus is 80 GPa.

Mechanical solicitations

In this study, using the nanoindenter, ten static loads ranging from 50µN up to 130mN are applied on the gold thin film at different locations with a spherical diamond tip of 50µm radius to be representative of microswitch contact pressure (Table 3). These experiments proceed as follow: after surface contact, the load increases with a constant strain rate (0,05 s -1 ). The targeted load is applied during 1 second, then unload occurs at the same strain rate.

To perform mechanical cycling in the same pressure range, an apparatus (Vincent [START_REF] Vincent | An original apparatus for endurance testing of mems electrical contact materials[END_REF]) for endurance testing in both hot and cold switching mode under constant voltage is used. In cold switching mode, the voltage between the probe and the gold film is only applied when the switch is closed, while the voltage is always applied in hot switching mode leading to closure and opening electrical effects. This apparatus is constituted by a commercial ferromagnetic reed blade (flexible beam) where the sample is glued and put into contact with a 20 μm curvature radius gold probe using a piezoelectric actuator having a displacement resolution of 10 nm as shown in Figure 1. The applied load is measured using a strain gage force sensor with 20 μN resolution. After first contact and load adjustment, an electromagnet located above the ferromagnetic beam is used for cyclic contact opening / closing actuation under sinusoidal excitation. Load, switching frequency, voltage and current compliance are respectively fixed to 300µN, 10 Hz, 5 V and 1 mA (Table 2).

In order to have a comparison criterion between the mechanical solicitations under static loading, cyclic loading and a real micro-switch, the equivalent average contact pressure (P eq ) corresponding to the applied load F is introduced and calculated from Hertz equation for a sphere / plane elastic contact (Eq. 1). F R E P eq eq 1 E eq and R are respectively the effective elastic modulus and curvature radius of indenter tip. The former being related to material properties by the following relationship: In the following part of the article the hertzian equivalent average contact pressure is always used. Load applied in a micro switch is about 10 μN. Therefore, for a contact bump curvature radius of 10 µm, the MEMS switch pressure is around 240 MPa. Endurance cycling experiments are carried out at 470 MPa (Table 2). On different test areas, 26 thousands and a half million cycles are respectively performed in hot and cold switching mode (Table 2). Static loads applied by spherical indentation are summarized Table 3. The range of MEMS switch pressure is investigated at low loads. At high loads, pressures above 1 GPa allow a high degradation analysis but obviously does not corresponds to the real applied pressure due to contact plastic deformation.

f f i i eq E E E 2 2 1 1

Static loading analysis

Geometry of the residual indent mark created under static loading (Table 3) at contact location is determined by AFM measurement. The diameter and depth of spherical indent and pile-up height are defined Figure 2. The indent depth (h) is defined as the difference between reference plane and bottom of indent. The pile-up height (s) is defined as the difference between the top of pile-up and reference plane. A gaussian filter is used to remove the short wavelength components as shown Figure 2. The diameter of the residual imprint obtained during indentation increases with applied pressure (Figure 3). It is observed that this increase of diameter follows the classic plastic model [START_REF] Anthony | [END_REF], where the hardness equals the ratio between the load and the projected contact area, such as the hardness equals 1 GPa. The experimental data and plastic model are represented Figure 3 respectively by points and a red line. The pile-up formation is observed above 500 MPa (Figure 5). The ratio (s/h) of pile-up height on indent depth increases from 0 to 0.5 with pressure applied. This is due to the transition from purely elastic deformation at low pressure to plastically dominated behavior at high pressure [START_REF] Pharr | Development of pile-up during spherical indentation of elastic-plastic solids[END_REF]. The pileup is a signature of thin film global plastic deformation.

Experimentally, indent marks created under pressures lower than 400 MPa are difficult to quantify. Only some asperities are partially hammered. The limit of detection corresponds to Tabor condition where plastic deformation starts over third part of hardness. Around 500 MPa, the roughness in the center of indent is around 4 nm and close to gold thin film value of 5 nm. When the pressure increases above 500MPa, the roughness decreases drastically to less than 2 nm due to plastic deformation. Before solicitation the average curvature radius of asperities on gold thin film is around 240 nm. Above 500 MPa of applied pressure, the average curvature radius of the asperities in the middle of the indent is of 850 nm showing huge plastic deformation of asperity summits added to global plastic deformation. The same evolution of the roughness and of the curvature radius of asperity after twelve millions cycles under 180 µN in [START_REF] Gregori | The interrelation between adhesion, contact creep, and roughness on the life of gold contacts in radio-frequency microswitches[END_REF] is found corresponding to an increase propensity to permanent adhesion.

The previous indents, already analyzed by AFM, are investigated by EBSD characterization as shown Figure 6. Comparison of both images demonstrates the one to one equivalency between topographic asperities with the grain shapes observed by EBSD. As previously shown, gold thin film has a strong {111} fiber texture. The grain circled Figure 6 at the middle of the indent mark obtained under a 1.6 mN static load suffers 10 degrees of rotation in comparison to the {111} initial fiber texture. Only grains in the middle of indent present a rotation. Therefore observed deformation is heterogeneous. Thus a 1x1µm² area is analyzed for each indent to determine average grain rotation as a function of average pressure. No grain size modification is observed on any indent. Rotation angle of grains increases with pressure above 500MPa (Figure 5). This rotation reaches 21° under an equivalent pressure of 3GPa. The ratio (s/h) of pile-up height on indent depth and the grain rotation follow the same evolution with applied pressure and are representative of the level of plastic deformation (Figure 5).These rotations induce the {111} fiber texture degradation. Central spot and external fringe on {111} pole figure are larger. In extreme cases, central spot transforms in new circle. This type of crystallographic texture deformation is also observed on polycristals under uniaxial compression [START_REF] Kalidindi | Polycrystalline plasticity and the evolution of crystallographic texture in fcc metals[END_REF]. This grain reorientation can be predicted by Taylor-type model of crystalline plasticity [START_REF] Kalidindi | Polycrystalline plasticity and the evolution of crystallographic texture in fcc metals[END_REF].

This demonstrates that EBSD analysis gives precious information on plastic deformation level. Therefore, this characterization technique will be applied on cyclic loading contact areas with interest.

Cyclic loading mode analysis

A half million cold switching cycles is performed as detailed Table 2. The setup of this experiment needs a first contact approach with the piezoelectric actuator. This first contact force is around 1 mN and induces a grain rotation of 10° (Figure 7-c). After the approach, mechanical cycling under a 300 µN load is performed by the sinusoidal signal send to the electromagnet. A grain rotation of 30° is observed after a half million cycles. This is due to cumulative plastic deformation. The grain rotation obtained is higher than under 3 GPa static loading contact pressure. The {111} Pole figure obtained has a strong crystallographic texture and is slightly different from static loads. First contact approach induces a shift of the {111} texture fiber. Then, mechanical cycling induces larger central spot and external fringe on the {111} pole figure .   A single indentation in the degradation area is performed (Figure 9). The measured hardness increases by 12% on a half million quasi cold switching cycles area at a 150 nm of depth. No grain size modification was observed on a half million quasi cold switching area. Therefore the measured hardness increase is due to strain hardening.

The same test is performed in hot switching mode. Grain Boundary rotation obtained for 26,000 hot switching cycles is around 25°, that is, of the same order than after a half million cycles cold switching experiment. Moreover, resulting crystallographic texture of the contact area is extremely different from previous tests. A strong degradation of the {111} fiber texture is observed but no particular orientation is predominant (Figure 7-d). The grain size has increased in contact area. The average grain size is around 250 nm, whereas initial average grain size of gold thin film is around 90 nm. Thermal energy produced during by hot switching (arcing or melting) induces an abnormal recrystallization. The grain size increase and the resulted crystallographic texture differ from previous solicitations and is the expression of a different mechanism of degradation.

A single indentation in the degradation area is also performed. At a depth of 150 nm, the measured hardness decreases by 22% compared to the initial gold thin film. This decrease of hardness could correspond to the Hall-Petch effect described by the following relation,

2 / 1 0 d H K H H 3
Where H 0 and K H are experimental constant and d is the average grain size (equation 3). More experiments in hot switching mode should be addressed to use this relation. A comparison with the results obtained in Cao study [START_REF] Cao | Nanoindentation measurements of the mechanical properties of polycrystalline au and ag thin films on silicon substrates: Effects of grain size and film thickness[END_REF] concerning the decrease of gold hardness with grain size is presented Figure 10.

Conclusions

The interest of EBSD analysis for micro-switch reliability study is demonstrated through this work. We have highlighted the following points:

The {111} pole figure evolution shows grain rotation due to plastic deformation, with good correlation with pile-up intensity.

The {111} pole figure gives information about the type of solicitation: compression.

The grain size determined by EBSD leads to the confirmation that thermal events occuring during hot switching are strong enough to concern the all grain volume and to induce grain growth.

The hardness measurements are coherent with microstructural evolution observed by EBSD.

Others points should be addressed to improve EBSD analysis and will be implemented into further studies. First, a crystallographic plastic model can be used to predict microstructural evolution, and secondly this type of analysis will be performed on the contact area of a real micro switch.

Figure 1 :Figure 2 :

 12 Figure 1 : Apparatus dedicated to cyclic loading test.

Figure 3 :Figure 4 :Figure 5 :Figure 6 :Figure 7 :

 34567 Figure 3 : Diameter versus equivalent pressure (Pa) of spherical indentation (50µm tip radius) in gold thin film.

Figure 8 :Figure 9 :Figure 10 :

 8910 Figure 8 : Scanning Electron Microscopy image (a) and EBSD map (b) of 26 thousand hot switching cycles contact area under 300 µN load.

1 2

 1 E and υ are Young's modulus and Poisson's ratio, subscripts f and i corresponding respectively to the film and to the indenter tip. Young's modulus and Poisson's ratio value for the gold thin film are E f =80 GPa (experimental) and ν f =0.44. The calculated effective elastic modulus for the different spherical indenter types are collected Table1.

		Ei (GPa)	νi	R (µm) Eeq (GPa)
	Gold-on-gold micro-switch	80	0.44	~10	49.6
	Spherical indenter (static)	1140	0.07	50	91.3
	Spherical gold probe (cyclic)	80	0.44	20	49.6

Table 1 :

 1 Young's modulus, Poisson's ratio and radii of different indenter types and their effective elastic modulus.

Table 2 :

 2 Cyclic loading, calculated pressure and number of cycles of tests performed.

	Cycling conditions	Hot switching (5V, 1mA, 10Hz)	Cold switching (5V, 1mA, 10Hz)
	Cyclic loading (mN)	0.3	0.3
	Pressure (MPa)	470	470
	Number of cycles	26 000	500 000

Table 3 :

 3 Static loads and calculated pressures applied by spherical diamond indentation (radius 50 µm).

	Static loading (mN)	0,05	0,22	0,55	1	1,6	7	18	37	73	130
	Pressure (MPa)	210	350	470	580	670	1100	1500	1920	2410	2920


Deepti Duvvuru

Jean-François Betzer
email: jean-francois.betzer@icsn.cnrs-gif.fr

Pascal Retailleau

Gilles Frison

Angela Marinetti
email: angela.marinetti@icsn.cnrs-gif.fr

An Easy, Stereoselective Synthesis of Hexahydroisoindol-4-ones under Phosphine Catalysis

Keywords: phosphine organocatalysis, conjugated dienes, imines, hexahydroisoindolones, [3+2] annulations

A new synthetic approach to hexahydroisoindol-4-ones is reported, based on the formal [3+2] cyclization reaction between N-arylsulfonylimines and cyclic conjugated dienes, under phosphine catalysis. Key substrates are 3-vinylcyclohex-2-enones with electronwithdrawing substituents (ester, amido, cyano, phosphoryl and keto groups) on the exocyclic double bond, which afford the three atom synthons for the construction of the pyrroline ring. Total syn stereoselectivity is observed in these annulations. The scope of the reaction has been demonstrated and mechanistic issues are considered, based on deuteration experiments and DFT calculations.

Introduction

Isoindoline units are commonly found in biologically relevant compounds and drug candidates displaying a remarkable variety of activities. [1] The related perhydroisoindol-4-ones have also found applications as core scaffolds or synthetic intermediates in medicinal chemistry. [2] Common synthetic strategies toward saturated fused bicyclic amines of this class mainly involve the 1,3-dipolar cycloaddition of azomethine ylides on suitable cyclic olefins [3] or Diels-Alder type reactions on maleimide. [4,[START_REF] Westling | For other methods[END_REF] Scheme 1 Synthetic approaches to perhydroisoindol-4-one scaffolds.

A new, alternative and practical synthesis of hexahydro-4H-isoindol-4-one derivatives is reported hereafter, based on phosphine catalyzed [3+2] cyclizations [START_REF] Lu | phosphine promoted annulation reactions[END_REF] which involve imines and dienes as the two atom and three atom components respectively. The method has been unexpectedly brought to light while expanding the scope of the recently disclosed reaction between electron-poor conjugated dienes and imines, under phosphine catalysis, shown in Scheme 2. [7] In this reaction, starting from acyclic conjugated dienes properly activated by electronwithdrawing groups on both ends, 3-pyrrolines were produced. [START_REF] Xu | For other synthetic approaches to pyrrolines by phosphine organocatalysis[END_REF] The cyclization took place selectively on the double bond substituted by the ester function, following to formal activation of this bond by the nucleophilic phosphine. Scheme 2. Synthesis of pyrrolines from conjugated dienes and imines under phosphine catalysis. [7] As a logical extension of this previous work, the same strategy has been applied then to conjugated dienes where one of the double bonds is embedded in a cyclic moiety. These experiments have allowed an efficient access to the hexahydroisoindol-4-one scaffolds 3 to be implemented, as shown hereafter.

Results and Discussion

With the purpose of expanding the scope of the phosphine promoted annulations reactions between imines and conjugated dienes shown in Scheme 2, [7] we have considered the known 3-(2-methoxycarbonylvinyl)-2-cyclo-hexenone 1a [9] as a model substrate for initial studies. Diene 1a has been reacted with N-tosyl-benzaldimine in the presence of trivalent phosphines as nucleophilic catalysts (Scheme 3). A clean reaction took place indeed, leading to the bicyclic pyrroline 3a, whose formation has been optimized by a rapid screening of catalysts (PBu 3 , PMe 3 , PMe 2 Ph, PMePh 2 , PPh 3 , P(i-Bu) 3 ) and reaction conditions. The optimized conditions include the use of PBu 3 as the catalyst, a 2:1 imine:diene ratio, polar solvents (methyl ethyl ketone or t-BuOH) and a reaction temperature of 80°C. In MEK, with a 10 mol% amount of the phosphorus catalyst, total conversion could be attained after 18h. Scheme 3. Phosphine promoted annulation between the cyclic diene 1a and imine 2a.

The molecular structure of 3a has been assigned at first by NMR and unambiguously established then by X-ray crystallography on the corresponding hydrazone 3a' (Figure 1). [START_REF]CCDC-786106 contains the supplementary crystallographic data for this compound. These data can[END_REF] NMR and structural data indicate that the reaction affords exclusively the syn isomer of the bicyclic fused pyrroline, with total chemo-and stereoselectivity. The outcome of this cyclization reaction highlights a stricking chemodivergent behaviour of the cyclic diene 1a with respect to the acyclic analogue I, as far as cyclization takes place on the enone function of 1a while it was shown to take place on the enoate function of I. This result rises some mechanistic concerns which will be discussed briefly in final section of this paper.

Since a variety of hexahydroisoindol-4-ones might be easily available from simple starting materials following the synthetic strategy typified in Scheme 1, we next examined the scope of this catalytic process. Representative results are depicted in Table 1. The cyclization reaction can be performed with tosylimines bearing substituted aryls, heteroaryls (entry 3) and alkyl groups (entry 7). It also tolerates p-chloro-and p-nitro phenylsulfonyl activating groups on the nitrogen atom (entries 8, 9), while N-DPP imines failed to react. Most reactions take place at 80°C with a 10 mol% amount of PBu 3 , but in some cases it may be advantageous to increase the catalyst amount or the temperature in order to increase the conversion rates. Both methyl ethyl ketone (MEK) and t-BuOH are suitable solvents. According to NMR analyses, the crude final mixtures contain 3 and, possibly, some residual starting material, with only minor amounts of side products. [a] Conditions: reactions have been performed at a 0.3 mmol scale, under Ar, in degassed MEK (1 mL, entries 1-5 and 8) or t-BuOH (1 mL, entries 6,7,9); diene:imine ratio = 1:1.5, unless otherwise stated. [b] Reaction temperature: 100°C. [c] diene:imine ratio = 1:2. [d] Diene:imine ratio = 1:3

The fused bicyclic pyrrolines 3b-j were obtained as single isomers which have been assigned as the syn isomers by analogy to 3a, based on their typical 1 H NMR pattern. The two NCH units display signals at δ = 5.6 (d, J ~ 1.2 Hz, NCHAr) and 5.0 ppm, while the chemical shifts of the CH 2 -CO 2 Me units are at about 3 ppm (AB system with 2 J H-H ~16 Hz, 3 J H-H ~4 and ~8 Hz).

Further efforts have been directed then toward modulation of the withdrawing group of the diene moiety (Scheme 4). Dienes 5a-e bearing keto, amido, cyano and diethylphosphoryl functions on the external double bond, have been prepared by Heck reaction from either 3-tosyloxy-or 3-bromo-2cyclohexenones and suitably functionalized olefins. They have been reacted then with Ntosylbenzaldimine in the presence of PBu 3 in MEK. Compared to 1a, the new dienic substrates 5 displayed lower reactivity, nevertheless the desired hexahydroisoindol-4-ones 6 could be obtained in moderate to good yields for reactions carried out at 100°C, with about 30 mol% catalyst. [11] In these reactions also, the final products were isolated as single isomers.

In additional experiments, variation of the ring size of the dienic substrate has been attempted by considering the five-member cyclic diene 7 as a possible reaction partner. Diene 7 has been prepared by Heck reaction between methyl acrylate and 3iodocyclopent-2-enone, [START_REF] Piers | [END_REF] with Pd(OAc) 2 / Ph 2 P(CH 2 ) 3 PPh 2 as the catalyst. In the usual conditions, the reaction of 7 with Ntosylbenzaldimine failed to give the expected pyrroline displaying a bicyclo-[3.3.0] scaffold. It produced however the aza-Morita-Baylis-Hillman adduct 8 in 70% yield. The aza-MBH reaction takes place selectively on the enone function, despite the fact that this will involve formal activation of a trisubstituted double bond by the phosphorus nucleophile. As far as we know, this is an unprecedented example of phosphine promoted aza-MBH reaction on a β-substituted cyclic enone.

In summary, results in Scheme 5 show that, in the case of cyclopentenone derivatives, the annulation reaction is no longer competitive with the direct elimination of the phosphine leading to the classical aza-MBH adduct. Therefore, the application field of our method is restricted so far to the synthesis of the [4.3.0]-bicyclic moiety of isoindolinones.

Finally, in order to expand the synthetic utility of the method, we have checked the feasibility of nitrogen deprotection in the final bicyclic product. To this end, we have considered the N-nosyl protected tetrahydroisoindolone 3j, since mild deprotection protocols are known for the nosyl group. The nosyl group could be removed actually by reaction of 3j with thiophenol in the presence of sodium carbonate (Scheme 6). [13] Scheme 6. Removal of the nosyl protecting group from isoindoline 3j.

The final secondary amine has been isolated from the crude reaction mixture, in pure form and good yield (66%), by extraction in acid solution. NMR data show that the bicyclic pyrroline ring is retained during the deprotection procedure.

Mechanistic considerations

On a mechanistic point of view, the most straightforward pathway for building the tetrahydroisoindolines 3 (or 6) would involve addition of the phosphorus nucleophile to the intracyclic double bond of 1 or 5 (path a in Scheme 7), followed by nucleophilic addition of A to the imine. Intermediate A1 should undergo then an intramolecular Michael type addition leading to A2. A formal [1,4]-proton shift will then convert A2 into A3 and create a negative charge β-to the phosphorus centre. The phosphine elimination step achieves the cyclization process. This mechanism implies the preferential activation of the internal, trisubstituted double bond of the starting diene, vs. activation of the disubstituted enoate function via intermediate B (Scheme 7b). This is rather unexpected, especially when considering that the related phosphine promoted aza-Morita-Baylis-Hillman reactions seldom apply to β-substituted Michael acceptors. [14,[START_REF] Shi | Only β-unsubstituted cyclic enones are common substrates for aza-Morita-Baylis-Hillman reactions[END_REF] Scheme 7. (a) A straightforward mechanism for the annulation reaction. (b) Alternative zwitterionic intermediates generated by phosphine addition to the conjugated dienes.

Therefore, in order to get additional information on possible reaction intermediates, the cyclization between 5a and 2a has been performed in the presence of excess D 2 O, as shown in Scheme 8.

Since H-shifts are known to be mediated by traces of water, [16] deuterium is expected to be incorporated on all positions involved in H-shift processes. The sample of 6a isolated from this experiment contains a significant amount of deuterium (70%) at the methylene carbon α to the COMe function. This was fully anticipated, due to the postulated formation of intermediate A2. However, deuterium has been partially incorporated also at the C1 carbon of 6a (30%) while the C3 moiety contains only protons.

The mechanism shown in Scheme 7a does not account, by itself, for the observed deuterium distribution, since it does not involve H-exchanges at the C1 carbon. Therefore, less straightforward mechanisms can't be excluded so far, which might involve initial addition of the phosphorus catalyst to other sites of the dienic moiety.

According to Hückel and quantum chemical calculations, the LUMO orbital of conjugated dienes such as 1a or 5a is distributed along the dienic unit, with roughly identical coefficients on the four atoms (Figure 2). When 5a was stirred at r.t. in the presence of PBu 3 and D 2 O, deuterium has been incorporated in comparable amounts on the α, γ and δ carbons of the starting dienic unit. Thus, experimental data and calculations support the hypothesis of an initial, reversible addition of the phosphorus nucleophile to various positions of the dienic substrate generating different zwitterionic adducts. The reaction outcome will be determined then at a later step of the catalytic cycle. Additional studies are required to enlighten the precise mechanism of these cyclization reactions.

Conclusion

This work demonstrates that the phosphinemediated organocatalytic annulations between 3vinylcyclohexenones and N-arylsulfonylimines produce hexahydroisoindol-4-ones with various functional groups connected to the C1-carbon by a CH 2 spacer. This represents a new, easy and stereoselective access to isoindoline derivatives with an unprecedented substitution scheme. Insights into the reaction mechanism have been obtained from deuteration experiments and DFT calculations which demonstrate the reversible addition of the phosphorus catalyst to the dienic unit.

The method proved unsuitable for the direct synthesis of the analogous 2-aza-bicyclo[3.3.0] units from cyclopentenone derivatives. Cyclic substrates with different ring sizes are now considered in ongoing studies.

Experimental Section

Synthesis of the conjugated dienes 1, 5 and 7 via Heck reactions. (a) Dienes 1a and 5a,c,e have been prepared from tosylate 4a according to the reported method. [9] Representative procedure: A mixture of tosylate 4a (4.0 g, 15 mmol), a suitable olefin H 2 C=CHZ (22 mmol), Et 3 N (3.3 mL, 24 mmol), Pd(OAc) 2 (50.6 mg, 0.22 mmol) and PPh 3 (59 mg, 0.22 mmol) in degazed N,Ndimethylacetamide (11 mL) / DMF (4.5 mL) was heated at 105°C under argon for 24h. The reaction mixture was routinely monitored by 1 H NMR. If needed, additional amounts of Pd(OAc) 2 /PPh 3 were added to achieve total conversion of the starting tosylate.After aqueous workup with HCl 0.5N, the organic layer was washed with NaHCO 3 and water and evaporated to dryness. The final product was purified by column chromatography on silica gel. (7). Diene 7 has been prepared by Heck reaction between 3iodocyclopent-3-enone [START_REF] Piers | [END_REF] and methyl acrylate. A mixture of 3-iodocyclopent-3-enone (0.50 g, 2.4 mmol), methyl acrylate (0.54 mL, 6 mmol), Pd(OAc) 2 (27 mg, 0.12 mmol), bis(diphenylphosphino)propane (25 mg, 0.06 mmol), Et 3 N (0.65 mL, 4.8 mmol) in DMF (10 mL) have been heated at 85°C for 16h. After aqueous workup with HCl 0.5N, the organic layer was washed with NaHCO 3 and water and evaporated to dryness. The final product 7 was purified by column chromatography on silica gel with an heptane/ethyl acetate gradient (R f = 0.3 in heptane/ethyl acetate 1:1). Yield: 0.20 g, 50%. Phosphine promoted cyclization reactions. General Procedure: PBu 3 (25-75 µmol) was added to a mixture of diene (0.25 mmol) and imine (0.50 mmol) in methyl ethyl ketone (or t-BuOH) (1mL) under argon. The mixture was heated overnight (18h) at the given temperature (see Schemes 3, 4 and Table 1). Conversion rates were determined on the crude mixture by 1 H NMR, with 1,3,5trimethoxybenzene as the internal standard. After evaporation of the solvent, the final product was purified by column chromatography on silica gel.

Methyl 2-(3-phenyl-4-oxo-2-tosyl-2,3,4,5,6,7-hexahydro-1H-isoindol-1-yl)acetate (3a). Compound 3a was obtained in 90% yield (98 mg) after purification with an heptane/ethyl acetate gradient (R f = 0.3 in heptane/ethyl acetate 1:1 ). 1 H NMR (CDCl 3 ): δ 7.66 (d, J = 8.2 Hz, 2H), 7.3-7.2 (7H), 5.61 (d, J = 1.2 Hz, 1H, N-CHPh), 5.03 (br, m, NCH), 3.74 (s, 3H, OMe), 3.17 (dd, J = 15.9 and 4.0 Hz, 1H, CH 2 CO 2 Me), 2.93 (d, J = 15.9 and 7.9 Hz, 1H, CH 2 CO 2 Me), 2.42 (s, Me), 2.4-2.2 (m, 4H), 2.0-1.9 (m, 2H); 13 9, 128.8, 127.9, 113.7, 67.8 (NCHAr) 8, 23.1, 21.7, 19.7, 18.8 (Me) ), 129.4, 129.2, 128.4, 128.1, 127.8, 127.2, 68.5 (NCHAr) ), 129.0, 128.6, 128.5, 127.9, 124.2, 68.8 (NCHAr), 65.9 (NCH), 52.4 (OMe), 39.6 (CH 2 CO 2 Me), 37.9 (CH 2 CO), 23.8, 23. ), 128.3, 127.9, 129.8, 127.7, 68.1 (NCHAr), 64.4 (NCH), 49.2 (CH 2 COMe), 37.7 (CH 2 CO), 30.9 (COMe) 23. 7, 22.9, 21.6 (Me) Computational methods. Geometry optimization was carried out at the B97-D level of theory [17] with the def2-TZVPP basis set. [18] These calculations were accelerated using the Multipole Accelerated Resolution of Identity for J (MARI-J) approximation method, [19] as implemented in Turbomole 6.2. [20] LUMO have been drawn using the gOpenMol 3.00 package. [21] The molecular orbital coefficients have been computed at the HF/STO-3G level, based on the DFT gas-phase geometries. [16c] Hückel calculations were carrried out with the Hückel simple program. [START_REF]An Easy Stereoselective Synthesis of Hexahydroisoindol-4-ones under Phosphine Catalysis[END_REF]

Figure 1 .

 1 Figure 1. X-ray crystal structure of hydrazone 3a'.

Scheme 4 .

 4 Scheme 4. Synthesis of hexahydroisoindol-4-ones with various functional groups tethered to the 1-position.

Scheme 5 .

 5 Scheme 5. Aza-Morita-Baylis-Hillman type reaction of vinylcyclopentenone 7 and N-tosylbenzaldimine.

Scheme 8 .

 8 Scheme 8. Cyclization reaction in the presence of D 2 O

Figure 2 .

 2 Figure 2. LUMO coefficients for the dienic carbon atoms at the HF and Hückel (in bracket) levels (top) and qualitative view of the LUMO at the DFT level (bottom) for A) 1a and B) 5a. Consequently, the zwitterionic species B, C and D (Scheme 7b) might also be formed by addition of the nucleophilic phosphine to the α, γ and δ positions of the dienic ketone. They might enter a catalytic cycle or, alternatively, their reversible formation might induce H/D exchange reactions accounting for the observed D-distribution in the final product 6a (Scheme 8). The reversible addition of tributylphosphine to the diene has been evidenced by the H/D exchange experiment shown in Scheme 9.

  has been obtained in 59% yield (0.85 g, 4.4 mmol) from tosylate 4a (2.0 g, 7.5 mmol) and N,N-dimethyl acrylamide (1.1 g, 11 mmol) (Method a). The final product has been purified by column chromatography with ethyl acetate (R f = 0.2) as the eluent. 1 H NMR (CDCl 3 ): δ 7.27 (d, J = 15.6 Hz, 1H), 6.69 (d, J = 15.6 Hz, 1H), 6.11 (s, 1H), 3.10 (s, 3H), 3.01 (s, 3H), 2.50-2.39 (m, 4H), 2.09-2.00 (m, 2H); 13 C NMR (CDCl 3 ): δ 199.8 (CO), 165.6 (CO-N), 154.5 (C), 141.9, 131.4, 123.5, 37.6 (Me), 37.4 (Me), 35.9, 25.1, 22.1 ppm. (E)-diethyl 2-(3-oxocyclohex-1-enyl)vinylphosphonate (5e) has been obtained in 73% yield (1.3 g, 5.0 mmol) from tosylate 4a (2.0 g, 7.5 mmol) and diethyl vinylphosphonate (1.1 g, 6.8 mmol). 1 H NMR (CDCl 3 ): δ 7.12 (dd, J H-P = 21.8 Hz, J = 17.4 Hz, 1H), 6.11 (t, J H-P ~JH-H = 17.7 Hz, 1H), 6.06 (s, 1H), 4.06 (m, 4H), 2.40 (m, 4H, OCH 2 ), 2.03 (m, 2H), 1.29 (t, J = 7.1 Hz, 6H, Me) ppm. 13 C NMR (CDCl 3 ): δ 199.7 (CO) 153.8 (d, J = 23.5 Hz), 147.9 (d, J = 6.6 Hz), 132.0 (=CH), 121.2 (d, J = 189 Hz, PCH), 62.1 (d, J = 6.0 Hz, OCH 2 ), 37.6, 24.5, 21.9, 16.3 (d, J = 6.1 Hz, Me); 31 P NMR (CDCl 3 ): δ 17 ppm. (b) Dienes 5b and 5d have been prepared by Heck reactions between 3-bromocyclohex-2-enone 4b and the corresponding olefins, following the same procedure. The reactions are completed after heating for 2h at 85°C. (E)-3-(3-oxo-3-phenylprop-1-enyl)cyclohex-2-enone (5b) has been obtained in 71% yield (0.92 g) from the bromide 4b (1.0 g, 5.7 mmol) and phenyl vinyl ketone (1.0 g, 7.5 mmol). 1 H NMR (CDCl 3 ): δ 7.90 (d, J = 7.0 Hz, 2H), 7.53 (m, 1H), 7.4 (m, 2H), 7.39 (d, J = 17 Hz, 1H), 7.21 (d, J = 17 Hz, 1H), 6.20 (s, 1H), 2.54 (m, 2H), 2.43 (m, 2H), 2.06 (m, 2H) ppm. (E)-3-(3-oxocyclohex-1-enyl)acrylonitrile (5d) has been obtained in 44% yield (0.37 g) from bromide 4b (1.0 g, 5.7 mmol) and acrylonitrile (0.40 mL, 6 mmol) after purification by column chromatography with an heptaneethyl acetate gradient as the eluent. 1 H NMR (CDCl 3 ): δ 7.13 (d, J = 16.5 Hz, 1H), 6.13 (s, 1H), 5.75 (d, J = 16.5 Hz, 1H), 2.50-2.42 (m, 4H), 2.11 (m, 2H) ppm. (c) (E)-methyl 3-(3-oxocyclopent-1-enyl)prop-2-enoate

  1 H NMR (CDCl 3 ): δ 7.63 (d, J = 15.9 Hz, 1H), 6.30 (d, J = 15.9 Hz, 1H), 6.29 (s, 1H), 3.78 (s, 3H), 2.7 (m, 2H), 2.49 (m, 2H); 13 C NMR (CDCl 3 ): δ 208.8 (CO), 168.3 (CO 2 Me), 166.2 (C), 138.6 (CH), 136.1 (CH), 125.0 (CH), 52.3 (OMe), 35.1 (CH 2 ), 27.0 (CH 2 ) ppm.

  C NMR (CDCl 3 ): δ 194.4 (CO), 170.7 (CO 2 Me), 158.5 (C=C-CO), 144.0 (C), 139.9 (C), 135.0 (C), 134.4 (C), 129.8, 127.8, 127.7, 127.6, 68.2 (NCHPh), 65.6 (NCH), 52.1 (OMe), 40.1 (CH 2 CO 2 Me), 37.7 (CH 2 CO), 23.6, 22.9, 21.5 (Me) ppm. HRMS (ESI) calcd. for C 24 H 25 NO 5 S [M+Na] + : 462.1351, found: 462.1360. IR (neat) ν 1732, 1673 cm -1 . Methyl 2-(3-(4-chlorophenyl)-4-oxo-2-tosyl-2,3,4,5,6,7hexahydro-1H-isoindol-1-yl)acetate (3b). Compound 3b was obtained in 93% yield (110 mg) after purification with an heptane/ethyl acetate gradient (R f = 0.3 in cyclohexane/ethyl acetate 1:1). 1 H NMR (CDCl 3 ): δ 7.65 (d, J = 8.0 Hz, 2H), 7.3-7.2 (6H), 5.55 (d, J = 1.2 Hz, 1H, N-CHAr), 5.0 (br, m, NCH), 3.74 (s, 3H, OMe), 3.16 (dd, J = 16.0 and 4.0 Hz, 1H, CH 2 CO 2 Me), 2.95 (d, J = 15.9 and 8.0 Hz, 1H, CH 2 CO 2 Me), 2.43 (s, Me), 2.4-2.2 (m, 4H), 2.0-1.9 (m, 2H); 13 C NMR (CDCl 3 ): δ 194.3 (CO), 170.6 (CO 2 Me), 158.8 (C=C-CO), 144.2 (C), 138.5 (C), 134.7 (C), 134.1 (C), 134.2 (C), 133.6 (C), 129.8, 129.0, 128.3, 127.8, 67.5 (NCHAr), 65.5 (NCH), 52.1 (OMe), 39.9 (CH 2 CO 2 Me), 37.7 (CH 2 CO), 23.6, 22.9, 21.5 (Me) ppm. HRMS (ESI) calcd. for C 24 H 24 ClNO 5 S [M+Na] + : 496.0961, found: 496.0950. IR (neat) ν 1732, 1675 cm -1 . hexahydro-1H-isoindol-1-yl)acetate (3c) was obtained in 78% yield after purification with an heptane/ethyl acetate gradient (R f = 0.3 in cyclohexane/ethyl acetate 1:1). 1 H NMR (CDCl 3 ): δ 7.55 (d, J = 8.2 Hz, 2H), 7.41 (d, J = 8.5 Hz, 2H), 7.34 (d, J = 8.5 Hz, 2H), 7.20 (d, J = 8.2 Hz, 2H), 5.58 (br, m, 1H, N-CHAr), 5.0 (br, m, 1H NCH), 3.70 (s, 3H, OMe), 3.13 (dd, J = 16.0 and 4.1 Hz, 1H, CH 2 CO 2 Me), 2.97 (dd, J = 16.0 and 7.4 Hz, 1H, CH 2 CO 2 Me), 2.36 (s, 3H, Me), 2.3-2.2 (m, 4H), 2.0-1.9 (m, 2H); 13 C NMR (CDCl 3 ): δ 194.4 (CO), 170.7 (CO 2 Me), 159.2 (C=C-CO), 144.5 (C), 143.9 (C), 134.6 (C), 134.2 (C), 130.0 (C), 128.2, 128.0, 125.3, 125.2, 67.9 (NCHAr), 65.8 (NCH), 52.2 (OMe), 40.0 (CH 2 CO 2 Me), 37.8 (CH 2 CO), 23.8, 23.0, 21.6 (Me) ppm. 19 F NMR (CDCl 3 ): δ -62 ppm. HRMS (ESI) calcd. for C 25 H 24 F 3 NO 5 S [M+Na] + : 530.1225, found: 530.1221. IR (neat) ν 1733, 1674 cm -1 . -isoindol-1-yl)acetate (3d) was obtained in 76% yield ( 85 mg) after purification with an heptane/ethyl acetate gradient (R f = 0.3 in cyclohexane/ethyl acetate 1:1). 1 H NMR (CDCl 3 ): δ 7.60 (d, J = 8.3 Hz, 2H), 7.19 (d, J = 8.3 Hz, 2H), 7.08 (dd, J = 5.2 and 1.2 Hz, 1H), 6.99 (dd, J = 3.5 and 1.2 Hz, 1H), 6.81 (dd, J = 5.2 and 3.5 Hz, 1H), 5.88 (br, m, 1H, N-CHAr), 4.91 (br, m, 1H NCH), 3.63 (s, 3H, OMe), 3.01 (dd, J = 16.0 and 4.2 Hz, 1H, CH 2 CO 2 Me), 2.80 (dd, J = 16.0 and 8.0 Hz, 1H, CH 2 CO 2 Me), 2.33 (s, 3H Me), 2.3-2.2 (m, 4H), 2.0-1.8 (m, 2H); 13 C NMR (CDCl 3 ): δ 194.4 (CO), 170.7 (CO 2 Me), 159.0 (C=C-CO), 144.4 (C), 144.2 (C), 135.0 (C), 134.7 (C), 130.0 (C), 127.8, 127.0, 126.6, 125.2, 65.5 (NCHAr), 63.5 (NCH), 52.2 (OMe), 40.4 (CH 2 CO 2 Me), 37.8 (CH 2 CO), 23.9, 23.1, 21.7 (Me) ppm. HRMS (ESI) calcd. for C 22 H 23 NO 5 S 2 [M+Na] + : 468.0916, found: 468.0918. IR (neat) ν 1734, 1676 cm -1 . Methyl 2-(3-(4-methoxyphenyl)-4-oxo-2-tosyl-2,3,4,5,6,7 -hexahydro-1H-isoindol-1-yl)acetate (3e). was obtained in 82% yield (96 mg) after purification with an heptane/diethyl ether gradient (R f = 0.3 in cyclohexane/ethyl acetate 1:1). 1 H NMR (CDCl 3 ): δ 7.62 (d, J = 8.3 Hz, 2H), 7.2-7.1 (m, 4H), 6.77 (d, J = 8.3 Hz, 2H), 5.54 (br, m, 1H, N-CHAr), 4.95 (br, m, 1H NCH), 3.74 (s, 3H, OMe-Ar), 3.68 (s, 3H, OMe), 3.09 (dd, J = 15.9 and 4.0 Hz, 1H, CH 2 CO 2 Me), 2.82 (dd, J = 15.9 and 7.8 Hz, 1H, CH 2 CO 2 Me), 2.37 (s, 3H Me), 2.3-2.2 (m, 4H), 2.0-1.9 (m, 2H); 13 C NMR (CDCl 3 ): δ 194.5 (CO), 170.8 (CO 2 Me), 159.3 (C=C-CO), 158.3 (C), 144.0 (C), 135.2 (C), 134.6 (C), 132.3 (C), 129.

  , 65.5 (NCH), 55.3 (OMe-Ar), 52.1 (OMe), 40.2 (CH 2 CO 2 Me), 37.8 (CH 2 CO), 23.8, 23.0, 21.6 (Me) ppm. HRMS (ESI) calcd. for C 25 H 28 NO 6 S [M+Na] + : 470.1637, found: 470.1619. IR (neat) ν 1732, 1673 cm -1 . isoindol-1-yl)acetate (3f) was obtained in 83% yield (101 mg) after purification with an heptane/ethyl acetate gradient (R f = 0.3 in cyclohexane/ethyl acetate 1:1). 1 H NMR (CDCl 3 ): δ 8.22 (d, J = 8.6 Hz, 1H), 7.66 (d, J = 8.6 Hz, 1H), 7.57 (d, J = 7.5 Hz, 1H), 7.46 (ddd, J = 8.6, 6.9 and 1.6 Hz, 1H), 7.4-7.3 (m, 3H), 7.2-7.1 (m, 2H), 6.85 (d, J = 8.6 Hz, 2H), 6.36 (br, m, 1H, N-CHAr), 5.20 (br, m, 1H NCH), 3.71 (s, 3H, OMe), 3.23 (dd, J = 15.9 and 3.8 Hz, 1H, CH 2 CO 2 Me), 3.06 (dd, J = 15.9 and 7.9 Hz, 1H, CH 2 CO 2 Me), 2.4-2.2 (m, 4H), 2.15 (s, 3H Me), 2.0-1.9 (m, 2H); 13 C NMR (CDCl 3 ): δ 194.2 (CO), 171.1 (CO 2 Me), 157.5 (C=C-CO), 143.7 (C), 136.5 (C), 136.2 (C), 134.4 (C), 133.6 (C), 131.4 (C), 129.2, 128.5, 128.3, 128.0, 126.0, 125.6, 125.0, 123.4, 65.4 (NCHAr), 63.2 (NCH), 52.2 (OMe), 40.1 (CH 2 CO 2 Me), 37.8 (CH 2 CO), 23.8, 23.1, 21.5 (Me) ppm. HRMS (ESI) calcd. for C 28 H 27 NO 5 S [M+Na] + : 512.1508, found: 512.1500. IR (neat) ν 1734, 1677 cm -1 . isoindol-1-yl)acetate (3g) was obtained in 47% yield ( 57 mg) after purification with an heptane/ethyl acetate gradient (R f = 0.3 in cyclohexane/ethyl acetate 1:1). 1 H NMR (CDCl 3 ): δ 8.04 (d, J = 8.8 Hz, 2H), 7.59 (d, J = 7.6 Hz, 2H), 7.46 (d, J = 8.8 Hz, 2H), 7.21 (d, J = 7.6 Hz, 2H), 5.59 (d, J = 2.4 Hz, 1H, N-CHAr), 4.96 (br, m, 1H NCH), 3.72 (s, 3H, OMe), 2.96 (dd, J = 16.1 and 3.9 Hz, 1H, CH 2 CO 2 Me), 3.15 (dd, J = 16.1 and 7.3 Hz, 1H, CH 2 CO 2 Me), 2.38 (s, 3H Me), 2.3-2.2 (m, 4H), 2.0-1.9 (m, 2H); 13 C NMR (CDCl 3 ): δ 194.3(CO), 170.7 (CO 2 Me), 159.7 (C=C-CO), 147.3 (C), 144.8 (C), 134.3 (C), 133.8 (C), 130.2 (C), 128.9, 128.1, 123.6, 67.7 (NCHAr), 65.9 (NCH), 52.4 (OMe), 39.8 (CH 2 CO 2 Me), 37.7 (CH 2 CO), 23.8, 22.9, 21.7 (Me) ppm. HRMS (ESI) calcd. for C 24 H 24 N 2 O 7 S [M+Na] + : 507.1202, found: 507.1187. IR (neat) ν 1733, 1676 cm -1 . Methyl 2-(3-isopropyl-4-oxo-2-tosyl-2,3,4,5,6,7hexahydro-1H-isoindol-1-yl)acetate (3h) was obtained in 71% yield ( 72 mg) after purification with an heptane/ethyl acetate gradient (R f = 0.3 in cyclohexane/ethyl acetate 1:1). 1 H NMR (CDCl 3 ): δ 7.67 (d, J = 8.3 Hz, 2H), 7.26 (d, J = 8.3 Hz, 2H), 4.76 (ddd, J = 8.9, 4.0 and 1.2 Hz, 1H, NCH), 4.57 (d, J = 2.2 Hz, 1H, N-CHAr), 3.72 (s, 3H, OMe), 3.04 (dd, J = 16.3 and 4.2 Hz, 1H, CH 2 CO 2 Me), 2.66 (dd, J = 16.3 and 8.8 Hz, 1H, CH 2 CO 2 Me), 2.38 (s, 3H Me), 2.3-2.2 (m, 1H), 2.1-2.2 (m, 1H), 1.9-1.8 (m, 1H), 0.97 (d, J = 7.0 Hz, 3H, Me) 0.97 (d, J = 7.0 Hz, 3H, Me); 13 C NMR (CDCl 3 ): δ 195.2 (CO), 171.2 (CO 2 Me), 159.2 (C=C-CO), 144.1 (C), 135.2 (C), 133.8 (C),130.0, 128.0, 71.1 (NCHAr), 65.9 (NCH), 52.3 (OMe), 40.6 (CH 2 CO 2 Me), 37.9 (CH 2 CO), 32.

  ppm. HRMS (ESI) calcd. for C 21 H 27 NO 5 S [M+Na] + : 428.1508, found: 428.1501. IR (neat) ν 1735, 1672 cm -1 . hexahydro-1H-isoindol-1-yl)acetate (3i) was obtained in 82% yield (94 mg) after purification with an heptane/ethyl acetate gradient (R f = 0.3 in cyclohexane/ethyl acetate 1:1). 1 H NMR (CDCl 3 ): δ 7.50 (d, J = 8.5 Hz, 2H), 7.25 (d, J = 8.5 Hz, 2H), 7.5-7.1 (m, 5H), 5.51 (d, J = 2.1 Hz, 1H, N-CHAr), 4.93 (br, m, 1H NCH), 3.58 (s, 3H, OMe), 2.98 (dd, J = 15.9 and 4.0 Hz, 1H, CH 2 CO 2 Me), 2.81 (dd, J = 15.9 and 7.5 Hz, 1H, CH 2 CO 2 Me), 2.2-2.1 (m, 4H), 1.9-1.7 (m, 2H); 13 C NMR (CDCl 3 ): δ 194.3 (CO), 170.6 (CO 2 Me), 158.2 (C=C-CO), 139.5 (C), 139.4, 136.5 (C), 135.1 (C

  , 65.7 (NCH), 52.2 (OMe), 40.0 (CH 2 CO 2 Me), 37.8 (CH 2 CO), 23.7, 23.0 ppm. HRMS (ESI) calcd. for C 23 H 22 ClNO 5 S [M+Na] + : 482.0805, found: 482.0794. IR (neat) ν 1732, 1674 cm -1 . hexahydro-1H-isoindol-1-yl)acetate (3j) was obtained in 44% yield (52 mg) after purification with an heptane/ethyl acetate gradient (R f = 0.3 in cyclohexane/ethyl acetate 1:1). 1 H NMR (CDCl 3 ): δ 8.15 (d, J = 8.8 Hz, 2H), 7.76 (d, J = 8.8 Hz, 2H), 7.19 (br, m, 5H), 5.69 (d, J = 2.4 Hz, 1H, N-CHPh), 5.13 (br, m, 1H NCH), 3.66 (s, 3H, OMe), 3.06 (dd, J = 15.8 and 4.4 Hz, 1H, CH 2 CO 2 Me), 2.94 (dd, J = 15.8 and 7.1 Hz, 1H, CH 2 CO 2 Me), 2.5-2.2 (m, 4H), 2.1-2.0 (m, 2H); 13 C NMR (CDCl 3 ): δ 194.1 (CO), 170.4 (CO 2 Me), 157.7 (C=C-CO), 150.2 (C), 144.4 (C), 139.0 (C), 135.0 (C

  1 ppm. HRMS (ESI) calcd. for C 23 H 22 N 2 O 7 S [M+Na] + : 493.1045, found: 493.1064. IR (neat) ν 1732, 1675 cm -1 . one (6a) was obtained in 91% yield (96 mg) after purification with an heptane/ethyl acetate gradient (R f = 0.3 in cyclohexane/ethyl acetate 1:1). 1 H NMR (CDCl 3 ): δ 7.61 (d, J = 8.3 Hz, 2H), 7.29-7.16 (m, 7H), 5.61 (d, J = 1.2, 1H, N-CHAr), 5.03 (ddd, J = 7.9, 4.0 and 1.2 Hz, 1H, NCH), 3.22 (dd, J = 17.4 and 3.3 Hz, 1H, CH 2 COMe), 2.93 (dd, J = 17.4 and 7.9 Hz, 1H, CH 2 COMe), 2.34 (s, 3H, Me), 2.2-2.0 (m, 4H), 2.13 (s, 3H, COMe), 1.9-1.7 (m, 2H); 13 C NMR (CDCl 3 ): δ 205.7 (COMe), 194.3 (CO), 159.2 (C=C-CO), 144.1 (C), 140.3 (C), 134.8 (C), 134.0 (C), 130.0 (C

1 . 1 . 1 .

 111 ppm. HRMS (ESI) calcd. for C 24 H 25 NO 4 S [M+Na] + :446.1402, found: 446.1416. IR (neat) ν 1711, 1671 cm -1 . one (6b) was obtained in 47% yield ( 57 mg) after purification with an heptane/ethyl acetate gradient (R f = 0.3 in cyclohexane/ethyl acetate 1:1).1 H NMR (CDCl 3 ): δ 7.9-7.8 (m, 1H), 7.7-7.6 (m, 1H), 7.6- 7.5 (m, 2H), 7.5-7.4 (m, 1H), 7.4-7.3 (m, 2H), 7.3-7.1 (m, 7H), 5.47 (d, J = 1.7, 1H, N-CHAr), 5.17 (ddd, J = 8.9, 3.0 and 1.7 Hz, 1H, NCH), 3.76 (dd, J = 17.4 and 3.1 Hz, 1H, CH 2 CO 2 Ar), 3.44 (dd, J = 17.4 and 8.9 Hz, 1H, CH 2 CO 2 Ar), 2.29 (s, 3H, Me), 2.2-2.1 (m, 4H), 2.0-1.8 (m, 2H);13 C NMR (CDCl 3 ): δ 197.4 (COAr), 194.6 (CO), 159.8 (C=C-CO), 144.2 (C), 140.4 (C), 134.0 (C), 130.1 (C), 130.0 (C), 129.0, 128.5, 128.0, 127.7, 126.6, 68.2 (NCHAr), 65.2 (NCH), 45.3 (CH 2 COAr), 37.9 (CH 2 CO), 24.2, 23.1, 21.7 (Me) ppm. HRMS (ESI) calcd. for C 29 H 27 NO 4 S [M+Na] + : 508.1559, found: 508.1582. IR (neat) ν 1671cm -isoindol-1-yl)acetamide (6c) was obtained in 68% yield ( 77 mg) after purification with an heptane/ethyl acetate gradient (R f = 0.3 in cyclohexane/ethyl acetate 1:1). 1 H NMR (CDCl 3 ): δ 7.68 (d, J = 8.3Hz, 2H), 7.33 (d, J = 8.0Hz, 1H), 7.3-7.1 (m, 5H), 6.86 (d, J = 8.0Hz, 1H), 5.44 (br, m, 1H, N-CHAr), 4.90 (br, m, 1H, NCH), 3.0-2.9 (m, 2H, CH 2 CONMe 2 ), 2.90 (s, 3H, NMe 2 ), 2.84 (s, 3H, NMe 2 ), 2.35 (s, 3H, Me), 2.2-1.8 (m, 6H); 13 C NMR (CDCl 3 ): δ 194.7 (CO), 169.5 (CH 2 CONMe 2 ), 160.7 (C=C-CO), 144.3 (C), 140.4 (C), 134.4 (C), 133.7 (C), 130.1 (C), 128.3, 128.0, 127.9, 68.1 (NCHAr), 66.9 (NCH), 39.1 (CH 2 CONMe 2 ), 37.8 (NMe 2 ), 35.7 (NMe 2 ), 24.3, 23.1, 21.7 (Me) ppm. HRMS (ESI) calcd. for C 25 H 28 N 2 O 4 S [M+Na] + : 475.1668, found: 475.1662. IR (neat) ν 1674, 1643 cm -yl)acetonitrile (6d) was obtained in 32% yield (32 mg) after purification with an heptane/ethyl acetate gradient (R f = 0.3 in cyclohexane/ethyl acetate 1:1). 1 H NMR (CDCl 3 ): δ 7.44 (d, J = 8.3Hz, 2H), 7.3-7.2 (m, 2H), 7.1-7.0 (m, 5H), 5.46 (d, J = 2.3 Hz, 1H, N-CHAr), 4.73 (br, m, 1H, NCH), 3.0-2.9 (m, 2H, CH 2 CN), 2.26 (s, 3H, Me), 2.2-2.1 (m, 4H), 2.0-1.9 (m, 2H); 13 C NMR (CDCl 3 ): δ 194.0 (CO), 154.9 (C=C-CO), 144.6 (C), 138.8 (C), 136.7 (C), 134.3 (C), 130.0 (C), 128.4, 128.2, 128.1, 127.9, 116.7 (CN), 68.7 (NCHAr), 64.6 (NCH), 37.9 (CH 2 CN), 23.9, 23.1, 21.7 (Me) ppm. HRMS (ESI) calcd. for C 23 H 22 N 2 O 3 S [M+Na] + : 429.1249, found: 429.1258. IR (neat) ν 1676, 2220 cm -yl)methylphosphonate (6e) was obtained in 41% yield (53 mg) after purification with an heptane/ethyl acetate gradient (R f = 0.3 in cyclohexane/ethyl acetate 1:1). 1 H NMR (CDCl 3 ): δ 7.57 (d, J = 8.4Hz, 2H), 7.2-7.1 (m, 7H), 5.44 (br, m, 1H, N-CHAr), 4.76 (br, m, 1H, NCH), 4.1-3.9 (m, 4H, OCH 2 ), 2.7-2.5 (m, 2H, CH 2 PO(OEt) 2 ), 2.29 (s, 3H, Me), 2.2-2.0 (m, 4H), 1.3-1.2 (m, 6H, OCH 2 CH 3 ); 13 C NMR (CDCl 3 ): δ 194.7 (CO), 159.5 (C=C-CO), 144.2 (C), 140.0 (C), 135.3 (C), 134.3 (C), 130.1 (C), 128.4, 128.0, 127.9, 127.7, 68.0 (NCHAr), 64.3 (NCH), 62.3 (d, J = 6.6 Hz, OCH 2 ), 62.0 (d, J = 6.6 Hz, OCH 2 ), 37.8, 34.2, 32.4 (CH 2 PO(OEt) 2 ), 29.8, 24.1, 23.2, 16.4 (d, J = 6.0 Hz, Me), 16.3 (d, J = 6.0 Hz, Me), ppm. 31 P NMR (CDCl 3 ): 25.5. HRMS (ESI) calcd. for C 26 H 32 NO 6 PS [M+Na] + : 540.1586, found: 540.1597. IR (neat) ν 1676 cm - 1 . yl)-acetate (3j'). To a solution of methyl {(1S*,3R*)-2-[(4-nitrophenyl)sulfonyl]-4-oxo-3-phenyl-2,3,4,5,6,7-hexahydro-1H-isoindol-1-yl}acetate 3j (30 mg, 0.06 mmol) and K 2 CO 3 (35 mg, 0.25 mmol, 4.0 equiv.) in CH 3 CN-DMSO (95:5) (1 mL) at room temperature was added PhSH (23 µL, 0.22 mmol). The reaction mixture was heated at 40 °C for 2 h. The crude mixture was diluted with AcOEt (10 mL) and HCl 1N (10 mL) and the layers were separated. The aqueous layer was basified with solid K 2 CO 3 (pH 10-11) and extracted with AcOEt (3x10 mL). The combined organic extracts were dried over MgSO 4 , filtered, and concentrated in vacuo to provide 3j' (12 mg, 66%). 1 H NMR (CDCl 3 ): δ 7.34 (d, J = 7.1 Hz, 2H), 7.30 (dd, J = 7.1 and 6.9 Hz, 2H),7.22 (t, J = 6.9 Hz, 1H), 5.25 (s, 1H, N-CHPh), 4.59 (dd, J = 4.4 and 4.1 Hz, 1H, NCH), 3.71 (s, 3H, OMe), 2.79 (dd, J = 15.6 and 4.1 Hz, 1H, CH 2 CO 2 Me), 2.60 (dd, J = 15.6 and 4.4 Hz, 1H, CH 2 CO 2 Me), 2.51-2.30 (m, 4H), 2.22 (br, s, NH), 1.55-1.26 (m, 2H). 13 C NMR (CDCl 3 ): δ 195.6 (CO), 171.8 (CO 2 Me), 162.3 (C=C-CO), 143.6 (C), 138.2 (C), 128.2, 127.5, 127.2, 65.7 (NCHPh), 63.1 (NCH), 51.9 (OMe), 41.0 (CH 2 CO 2 Me), 38.2 (CH 2 CO), 23.8, 23.5 ppm. HRMS (ESI) calcd. for C 17 H 19 NO 3 [M+H] + : 286.1443, found: 286.1449. IR (neat) ν 1733, 1669 cm -1 .

Table 1 .

 1 Phosphine promoted synthesis of the hexahydroisoindol-4-ones 3: variations of the imine partner.

	Imine	R	R 1	PBu3 %	Prod.	Yield % [a]

Acknowledgements

We are grateful to ICSN and to the Agence Nationale de la Recherche (ANR) for financial support. This work has been done within the PhoSciNet COST action.


J Bourcier
email: jbourcie@doc.ic.ac.uk

A Diaconescu
email: ada.diaconescu@imag.fr

P Lalanda

Julie A Mccann

AutoHome: an Autonomic Management Framework for Pervasive Home Applications

Keywords: D.2.13 [Software] -Reusable Software --Domain engineering Design, Performance, Experimentation, Reliability Autonomic Computing, Service Oriented Computing, Pervasive computing, Framework ACM

This paper introduces the design of the AutoHome service oriented framework to simplify the development and runtime adaptive support of autonomic pervasive applications. To this end, we describe our novel open infrastructure for building and executing home applications. This includes the amalgamation of the two computing areas of Autonomics and Service Orientation, to produce a Component-based platform providing facilities including monitoring, touchpoints and other common autonomic services. This infrastructure uniquely blends the advantages of distributed autonomic control with global conflict management in a management hierarchy. We discuss this platform in terms of pervasive home systems and show how one would develop such a system for two examples of automated home applications: intruder detection and medical support respectively. Both applications were built within our framework and evaluated showing that the use of the framework introduces minimal overheads but provides many benefits. We then conclude by highlighting the contributions of AutoHome and a discussion about the lessons learned, limitations and future research directions.

In previous work [START_REF] Bourcier | Implementing Home-Control Applications on Service Platform[END_REF][START_REF] Escoffier | Towards a home application server[END_REF] we proposed a software platform simplifying the development and execution of pervasive home applications. It was based on a serviceoriented approach, providing modularization, loose-coupling and dynamic properties. Although this platform supported system adaptability and evolution such as dynamic service bindings, it lacked functionalities to dynamically monitor and reconfigure each service as well as the facilities for enforcing and controlling dynamic modifications that maintain global system coherence to adherence to goals. Indeed, managing complex, adaptive pervasive applications is no easy task.

Autonomic Computing [START_REF] Kephart | The Vision of Autonomic Computing[END_REF] promises a solution to the aforementioned problem, by endowing software systems with self-management capabilities that would minimize or eliminate the need for human intervention. If successfully implemented, autonomic pervasive applications would inherently feature critical properties such as safety (including fault-tolerance and security) and self-adaptation to internal and external changes (including self-configuration, self-optimization and self-repair).

This paper presents AutoHome, a project for providing reusable support for the development of viable Autonomic Management (AM) applications in the pervasive computing domain. The main contributions of this project are:  The design, development and open-source contribution of a specific service-oriented component framework for autonomic applications. This proposition has been implemented as specific iPOJO [START_REF] Escoffier | iPOJO An extensible service-oriented component framework[END_REF] extensions enabling dynamic service monitoring and reconfigurations (autonomic touchpoints).  The design and development of an open and dynamic hierarchical autonomic management infrastructure to enable the creation of autonomic solutions in the pervasive home environment.  The experimentation and validation of the proposed framework through collaboration with industrials within the ITEA ANSO (http://anso.vtt.fi/) and OSAMI COMMONS (http://www.osami-commons.org/) projects.

BACKGROUND & MOTIVATING EXAMPLES

Home automation [START_REF] Helal | The Gator Tech Smart House: A Programmable Pervasive Space[END_REF] corresponds to a subset of pervasive applications that deals with the automation of home device control. Several application areas are covered by home automation ranging from the monitoring of convalescents at home, to home theater and energy consumption control. This work is evaluated using two such application scenarios: a security-oriented application and a patient monitoring system. The purpose of the security system is to monitor home intrusion through the use of a webcam and motion detector. The application structure is made of several services. When particular motion patterns are recognized through the image stream, an alert is sent according to user preferences and the current availability of communication mediums. The second application uses medical sensors to gather patient data. Such sensors include blood pressure sensors, heart-rate monitors or thermometers. This application is composed of several services ensuring crisis situation detection and daily production of health report. These two applications' structure is presented in appendix A.

The inherent nature of these applications requires continuous execution and maximum quality of service. Therefore, dynamic adaptation to their current environment is essential to ensure that these applications remain within the functional boundaries defined by application designers, as well as maintain their performance, security and safety properties. Thus, a framework supporting the development of such applications has to support dynamic monitoring and reconfiguration of running applications, dynamic integration of new applications and inter-application management.

AutoHome: an Autonomic Management Framework for Pervasive Home Applications

THE AUTOHOME AUTONOMIC FRAMEWORK

A review of autonomic frameworks enabling dynamic adaptation to their execution context is presented in Appendix B.

Overall Architecture

Our proposal is to build a middleware serving as a framework to host autonomic home applications. Our approach is to separate the design and development of the application itself from autonomic management components. The goal is thus to enable the development of autonomic management functions, seamlessly integrate them with the applications and finally integrate the resulting autonomic application with other applications sharing the same execution environments. Typically an application on top of AutoHome, illustrated in Figure 1, has the following architectural elements:  A middleware for autonomic service-oriented applications composed of an autonomic service-oriented component and a context facility. The runtime includes a set of generic and configurable touchpoints allowing dynamic application monitoring and reconfiguration.  A set of Service-Oriented applications built on top the middleware, which represent pervasive components to be autonomously managed.  A set of autonomic managers organized in a hierarchy. As a reminder, Service-Oriented Computing (SOC) [START_REF] Papazoglou | Service-oriented computing[END_REF] is a recent trend in software engineering that uses services as basic elements for building applications. A service represents a computational entity described by a specification covering both functional (service interface) and non-functional (QoS) aspects. At runtime, available services are registered in one or more service brokers where they can be discovered by service consumers. A service consumer is then able to invoke the service based on the service specification. An important consequence of this interaction pattern is that SOC technologies support dynamic service discovery and lazy inter-service binding. Such characteristics are essential when building applications with strong adaptability requirements, such as pervasive and residential applications.

iPOJO [START_REF] Escoffier | iPOJO An extensible service-oriented component framework[END_REF] is the Apache service oriented component runtime built on top of OSGi [START_REF]OSGi Service Platform Core Specification Release 4‖[END_REF] SOA Platforms. The iPOJO framework merges the advantages of component and service oriented paradigms. Specifically, application functionalities are implemented following the component paradigm. Each component is fully encapsulated, self-sufficient and provides server and client interfaces as services. An iPOJO component is actually managed by a reusable container which provides common middleware functionalities. Each component container can be configured with a different set of middleware services.

A Hierarchical Management Architecture

As rapidly introduced, autonomic managers are organizes in a hierarchy. This hierarchy relates to two aspects: authority and abstraction. A manager of a higher level has higher authority, and therefore precedence over a lower level manager. The hierarchy is also used to mask the management complexity by raising the abstraction of models used by higher managers. These two properties provide the scalability feature to our management architecture while avoiding the conflict management issue of entirely decentralized architectures. In our system, an autonomic manager is integrated with the autonomic managers' hierarchy and the system to be managed. Inter managers communications are thus possible and aim at guarantying or modifying the behavior of non managed resources. Managers remain sovereign of their decisions on the resource they control.

Our architecture, as seen in figure 2, offers three types of autonomic managers: service managers, application managers and a gateway manager. Service managers finely control the internal behavior of the service and optimize its functionalities. Application managers control the life cycle of an application and its constituent services. One gateway manager is attached to the overall framework. It governs the physical resources of the gateway and arbitrates conflicts between applications.

Middleware's Touchpoints

Our middleware is an extension of iPOJO. The use of a service-oriented approach is mainly motivated by its inherent support for plural management authority, and dynamic reconfiguration whereby a service's implementation can be replaced during runtime. Such dynamic capabilities are essential for autonomic home applications.

Our middleware offers a dedicated component model for autonomic pervasive applications by proposing a set of generic touchpoints, which monitor and control the execution of pervasive applications. Touchpoints constitute the interface between autonomic managers and running applications. Our middleware offers dedicated touchpoints to each type of autonomic manager presented in the previous section. AutoHome offers a set of generic iPOJO handlers, covering the whole set of possible monitoring and reconfiguring activities. These handlers can be independently added after the development of a service (principle illustrated in figure 3). We identify three touchpoints for monitoring: property value, method invocation, and container's state. The property value touchpoint monitors either actively or passively any service attribute. The method invocation touchpoint enables monitoring through the call of a particular method. Finally, the container's state touchpoint enable precise monitoring of the container's state. We identify three actuators touchpoints: property value modification, method invocation, and container's state reconfiguration. The property value modification touchpoint offers the possibility of modifying the value of a property. The method invocation touchpoint offers the possibility to call a method in order to modify the internal service behavior. The container's state reconfiguration touchpoint enables the modification of the container's configuration. Application managers have the possibility to control the life cycle of service instances with their associated autonomic manager. Thus an application manager may add, withdraw, start or stop services. Connections between services are carried out by the created instances. The particular instance configurations and their behavior adaptations are carried out by the service manager. Using these touchpoints, an application manager is able to dynamically modify applications' topology.

The gateway manager is in charge of maintaining gateway performance and attending to conflict management between applications. It is also in charge of the regulation of the memory load, processor usage and the framework bandwidth. Hence, the touchpoints available to the gateway manager allow the monitoring of physical parameters of the framework. The action touchpoints correspond to the deployment and withdrawal of new components.

EVALUATION -PERFORMANCE ASSESSMENT

To comparatively evaluate the performance of our framework, we have implemented two autonomic managers with and without using our framework; allowing us to evaluate the framework overhead in terms of performance. We thus compared the CPU consumption and did not find a significant difference between the two. This is mainly due to the time scale of the reconfigurations in our testing scenario. Indeed, as reconfiguration does not happen very often (one every 30-40 seconds), the overhead of the framework is not visible in the scenario's time scale. We also have evaluated the overhead in terms of memory footprint. For the security application, the overhead is between 6% and 13% for our two applications. We have also compared the number of lines of code of the autonomic management part for both applications (These applications are presented in section 2 and their implementation are presented in Appendix C). For the security application, the management part is 354 lines of code with our framework, while it is 503 lines of code without our framework. For the patient monitoring application, the management part is 118 lines of code with our framework while it is 156 without. We therefore consider that giving the low overhead and the benefit in lines of code, our framework succeeds in helping developers design autonomic applications in an open pervasive environment. More details about the evaluation can be found in Appendix C.

CONCLUSION

In this paper we discussed the design of AutoHome, a framework based on a serviceoriented component platform simplifying the development and supporting the executions of multiple autonomic pervasive applications in parallel. The first contribution of our work is the provision of a dedicated middleware to support the execution of autonomic smart home applications through a dedicated service-oriented component model to build smart home autonomic applications. This model includes a set of touchpoints that safely and non-intrusively monitor and reconfigure services. The second contribution of our framework is the hierarchical management infrastructure ensuring consistency throughout the smart home gateway, and enabling dynamic integration of new applications. Some parts of the presented middleware are currently used on several open source projects and in the context of European projects. The evaluation of the prototype presented in section 4 and appendix B highlights the benefits of AutoHome: reducing the complexity of building autonomic applications in pervasive environments, providing guidelines on the development of these applications, and finally providing the basic infrastructure to support the co-existence of several independent autonomic applications.

From this work, we derive three main lessons. Hierarchical management architectures are essential when dealing with such complex systems. Indeed, different types of reactions, time scales and concerns apply at different levels of the hierarchy. As such, policy expressions and algorithms to enforce them may largely differ between these managers. The openness of such infrastructure is essential to maintain users' freedom. Indeed, new features, electronic devices and applications will become progressively available, and users should have the possibility to seamlessly integrate them in their smart home environment. And finally, the complexity of providing a reliable runtime enabling safe monitoring and dynamic reconfiguration is often underestimated. Indeed, synchronization issues are very complex when dealing with dynamic systems.

AutoHome currently provides very limited integrated autonomic loop. Thus, we are working on providing specific autonomic loops. Specifically, we seek to improve the automatic choice between service providers based on particular needs of consumers, and to provide feedback on the perceived trust of available service provider. Another limitation of our framework lies in the management policy expression, which is currently done by developing autonomic managers. We are therefore planning to integrate well known policy expression, such as goal-based or utility function based policies.

  , A. Diaconescu, P. Lalanda and J. A. McCann ACM Trans. Transactions on Autonomous and Adaptive Systems (TAAS).

• 9: 3 ACM

 3 Trans. Transactions on Autonomous and Adaptive Systems (TAAS).

Figure 1 .

 1 Figure 1. An application on top of the AutoHome framework.

  , A. P. Lalanda and J. A. McCann ACM Trans. Transactions on Autonomous and Adaptive Systems (TAAS).

Figure 2 .

 2 Figure 2. Global Management Architecture of the AutoHome Framework.

Figure 3 .

 3 Figure 3. Integration of touchpoints into a Service-Oriented Component

APPENDIX Appendix A: Related Work

The study of various research domains that make up the landscape of autonomic computing reveals the diversity of research conducted in this area. We note that a significant number of work build autonomic applications without using any software engineering techniques or tools. Consequently, most current approaches target specific problems and too few are interested in building reusable frameworks or tools capitalizing on the available research in this domain. This notice corresponds to one of the conclusions of [START_REF] Parashar | AutoMate: Enabling Autonomic Grid Applications[END_REF], in which authors present a state of the art of autonomic computing and establish a set of challenges for this domain. Thus our related work focuses on comprehensive solutions for simplifying the production of autonomic applications.

IBM has produced an autonomic architecture defining a generic structure enabling the creation of autonomic applications [START_REF] Kephart | The Vision of Autonomic Computing[END_REF]. This architecture intends to be very general and establish a structure for building autonomic applications and the decomposition of the autonomic management function. The IBM autonomic manager is composed of five distinct components: knowledge-base, monitoring, analysis, planning and execution. An autonomic manager is attached to a managed system through touchpoints allowing interaction (monitoring and actions).

This architecture is mainly a generic platform to which developers should refer but does not propose any concrete solution for developing applications. Knowledge representation is at present a very complex problem to which no generic solution exists. Another major issue concern communication between autonomic managers. Indeed, the content and methods used to exchange information between autonomous elements are not specified. Finally, this system is assuming, more or less explicitly, fully decentralized management architecture for the system which is not always possible or welcomed (as we discuss later). Therefore, solely relying on this architecture to develop autonomic applications is not sufficient, thus the more recent focus on Autonomic Frameworks.

Autonomia [START_REF] Garlan | Rainbow: architecture-based selfadaptation with reusable infrastructure[END_REF], from the University of Arizona, study a holistic approach to control and manage resources and services available in the networks, and is essentially an implementation of the IBM framework. The management architecture proposed can be either hierarchical or fully decentralized. AutoMate [START_REF] Papazoglou | Service-oriented computing[END_REF], developed at Rutgers University, covers all key technologies including programming models, platforms and middleware to develop autonomic applications for the Grid. AutoMate uses ECA rules to manage applications and extends IBM's architecture with the concept of global application level policies, which are then decomposed and interpreted by each autonomic manager. Rainbow [START_REF]OSGi Service Platform Core Specification Release 4‖[END_REF] is a project developed at Carnegie Mellon University. This project aims at adapting complex systems by using an architecture-based approach. This system is based on an architecture model constantly updated through a set of probes.

These projects exemplify and complement the IBM architecture by specifying autonomic management techniques, such as policy expression, management architecture, and runtime model. Nevertheless, none of them proposes a reusable framework natively including generic touchpoints to easily plug autonomic managers. Furthermore, these projects do not consider pervasive computing specificity: that is, managing multiple independent applications with very volatile software and hardware resources.

A.1 Centralized versus Decentralized architectures

The most commonly used architecture in the literature is centralized, corresponding to a single autonomic manager for the entire system. Despite its large adoption, this architecture does not suit the home environment for many reasons. A residential gateway is intended to run a group of independent applications each containing several services. These applications can be deployed, updated or removed independently from each other. The use of centralized management requires global and detailed knowledge of all applications present on the framework and thus must be updated as soon as an application appears or is removed.

Alternatively, decentralized architectures can overcome the limitations of centralized architectures. However, their use to deal with autonomic residential applications also brings thorny issues. Even if the architecture permits integration of applications coming from different authorities, handling conflicts emerging from two contradictory decisions may become very complex. Indeed, arbitrating such conflicts may involve complex negotiation protocols, which are time consuming and hardly predictable.

A compromise between these approaches can be obtained through a hierarchical architecture. Indeed, this architecture enables different applications and service suppliers to control their own software while maintaining a global vision to handle conflicts and guarantee global properties.

Appendix B: AutoHome Evaluation

As described in [19], the evaluation of autonomic systems is a complex task and it requires the consideration of several aspects. We evaluate the AutoHome application in terms of behavior, through the implementation of the two aforementioned motivating examples presented in section 2. We assess AutoHome performance by comparing applications with and without AutoHome's autonomic extensions. All presented results were conducted on a laptop with Intel core 2 duo at 2.4GHz and 2 GB of memory.

The implementation of the security system involves two versions of the motion detector service: one is very accurate but demands a high level CPU, while the other is less accurate but demands less CPU. We have added four autonomic managers to this application. An autonomic manager for the image retrieval service, which has two modes of operation: restricted and unrestricted. The unrestricted mode produces images at high resolution (640*480) and frequency (5 seconds), whereas the restricted mode produces images at low resolution (320*240) and frequency (10 seconds). An autonomic manager for the image storage service, which again has two operation modes: normal and replacement. The normal mode adds images to a database. The replacement mode removes the oldest image and stores a new one. This manager also embeds a full autonomic control loop to provide switching between these two modes when memory thresholds are reached. An autonomic manager for the alarm service, is in charge of choosing the best communication medium for alerting users. This manager also takes charge of propagating emergency situation detection to application manager. An autonomic manager for the global application chooses between the two implementations of the motion detector. This manager is also in charge of dealing with the emergency situation by ordering all services to operate in their most accurate mode.

Figure 8 presents the curves of CPU and memory usage of this application for the following scenario. This scenario begins by injecting a high load on the processor (Label 1). The gateway manager detects the high CPU usage and asks the application manager to lower its CPU consumption. The application manager then asks the image retrieval manager to switch its operating mode to "restricted" and also changes the motion detection service implementation (Label 2). The storage service then reaches its maximum size and the manager switch its operational mode to replacement (Label 3). An alarm is then triggered and the manager consequently wants to have optimum an Autonomic Management Framework for Pervasive Home Applications detection conditions, meaning that the camera driver runs in "unrestricted" mode and that the motion detector service mode is at its most accurate (Label 4). The current level of load on the CPU is too high to allow this change. We reduce the injected load and observe that the reconfiguration is completed. Finally, we dump the memory and note that the storage service returns to its normal operation mode (Label 5). The second application has been enhanced with three autonomic managers. An autonomic manager for a blood pressure sensor, which has two modes: an accurate mode with a high frequency of blood pressure sampling, and a normal mode with low frequency of blood pressure sampling. An autonomic manager for the anomaly detector monitors the internal state of the anomaly detector. When a problem is detected, the autonomic manager asks the blood pressure sensor manager to switch to the accurate mode. An autonomic manager for the report creation service, is in charge of managing the memory. When no more space is available, the manager automatically creates the daily report and sends it to the hospital thus freeing up memory. We finally evaluate the framework by running both applications concurrently showing how they conflict. The results are presented in figure 10. At the beginning, very little memory is allocated to the medical supervision application since little disk space is required. The image storage manager reaches its maximum quota and switches from normal to replacement mode (Label 1). Then, the report builder manager reaches its maximum allocated space (Label 2). It asks its application manager for more disk space; the application manager transmits the request to the gateway manager, which then reduces the disk space allocated to the intrusion monitoring application and increases the space allocated to the medical monitoring application. After that, the report builder manager reaches again its maximum disk space (Label 3), but its request is denied because the intrusion monitoring application cannot operate with a smaller disk space. Therefore, the manager triggers the creation of a report to clear memory.