WO2000064908A1

WO2000064908A1 - N-tri or di-alkylsilyl( perfluoroal kanesulphonyl) imide derivatives, preparation and use

Info

Publication number: WO2000064908A1
Application number: PCT/FR2000/001028
Authority: WO
Inventors: Jean-Roger Desmurs; Léon GHOSEZ; Benoît MATHIEU
Original assignee: Rhodia Chimie
Priority date: 1999-04-23
Filing date: 2000-04-19
Publication date: 2000-11-02
Also published as: FR2792636A1; AU4126600A

Abstract

The invention concerns N-tri or di-alkylsilyl( perfluoroal kanesulphonyl) imide derivatives of general formula (I). The invention also concerns a method for preparing said compounds and their use as Lewis acids.

Description

N-TRI- OR DI-ALKYLSILYL (PERFLUOROALKANESULFONYL) LMIDE DERIVATIVES, THEIR PREPARATION PROCESS AND THEIR APPLICATION AS LEWIS ACIDS.

The subject of the present invention is N-tri- or di-alkylsilyl bis (perfluoroalkanesulfonyl) imide derivatives, their preparation process and their application as Lewis acids.

Recently, the inventors have shown that the N-trimethylsilyl-bis (perfluoromethanesulfonyl) imide has, compared to trimethylsilylperfluoromethanesulfonyl, a particularly advantageous behavior for the activation of the Diels-Alder reactions (L. Ghosez et al. T. Letters vol 38, No. 31, pp. 5497-5500. 1997). It proves capable of ensuring a wide variety of Diels-Alder reactions with satisfactory yields.

The object of the present invention is precisely to propose new compounds, related to N-trimethylsilyl-bis (perfluoromethane-sulfonyl) imide, which can also be used as Lewis acids to activate reactions using dienophilia and enophiles and more generally for the activation of carbonyl compounds and which, moreover, have, for some of them, the advantage of inducing an asymmetric synthesis. More specifically, the subject of the present invention is a compound of general formula I

in which y represents an integer equal to 1 or 2 and z zero or 1 with the sum of y + z being equal to 2, Rf represents (i) a halogen atom, preferably fluorine,

(ii) a poly- or per-halogenated, preferably C 1 to C ₁₀ alkyl radical, the polyhaloalkyl chain of which is optionally interrupted by one or more oxygen or sulfur atoms, (iii) a poly- or per-halogenated aryl radical, preferably C ₆ to C 12, or

(iv) a radical chosen from R _A -CF ₂ , RA-CF ₂ -CF ₂ -, RA- CF ₂ -CF (CF ₃ ) -, CF ₃ -C (R _A ) F- and (CF ₃ ) R _A - with R _A having any of the meanings given below for R, it being understood that R _A does not represent either a halogen atom or a polyhalogenated organic radical,

R represents Rf or

(i) an alkyl chain, preferably Ci to C-, optionally interrupted by one or more oxygen or sulfur atom (s) or carbonyl function (s) and optionally substituted by one or more halogen atoms or groups carboxyl or silyl,

(ii) an alkenyl chain, preferably from C ₂ to C 10, optionally interrupted by one or more oxygen or sulfur atom (s) or carbonyl function (s) and optionally substituted by one or more atom (s) halogen or carboxyl or silyl group (s);

(iii) an aryl group, preferably C ₆ to C ₂ , optionally substituted by one or more halogen atom (s) or alkyl or alkenyl group (s); (iv) an arylalkyl group, preferably from C to C ₁ , optionally substituted by one or more halogen atom (s);

(v) an arylalkenyl group, preferably from C ₈ to C ₁₅ , optionally substituted by one or more halogen atom (s);

(vi) -CO-R _E group with RE represents a halogen atom or an alkyl C l -C _4;

(vii) a group -0-CR _C RD-RB with R _B representing an alkylperfluorinated radical preferably in Ci to C-ι ₀ ; and R _c and R _D being, independently of each other, a radical chosen from (i), (ii), (iii), (iv) and (v) above, it being understood that Rc and R _D do not carry no halogen atom; - n is an integer equal to 1 or 2, m is an integer equal to 2 or 3 with the sum n + m being equal to 4, A represents 2 or 3 identical or different substituents chosen from hydrogen and halogen atoms, and hydrocarbon radicals having from 1 to 20 carbon atoms which may be a saturated or unsaturated, linear or branched acyclic aliphatic radical; a saturated, unsaturated, aromatic, monocyclic or polycyclic cycloaliphatic radical; optionally carrying a cyclic radical, aromatic or not, or a saturated or unsaturated, linear or branched aliphatic radical with the alkyl chain which can be interrupted by one or more oxygen atoms and / or units

It is optionally substituted at the end of the chain by an aromatic or non-aromatic cyclic radical; said radicals may optionally be substituted by one or more halogen atoms, preferably fluorine and / or one or more alkyl to C _6, preferably C ₄ -C or two of the groups A are linked so as to constitute a cycloaliphatic radical as defined above, provided that when z = 0 and n is equal to 1 and Rf represents a radical CF ₃ then the three groups A do not simultaneously represent either a methyl radical or a radical isopropyl or if one of the groups A represents a tert-butyie radical, then the other two groups A are different from a methyl radical, with said compound having at least one center or axis of chirality at the level of its structure, and its derivatives.

Preferably, the present invention relates to a compound of general formula (la)

in which :

- n is an integer equal to 1 or 2,

- m is an integer equal to 2 or 3 with the sum n + m being equal to 4, A represents 2 or 3 substituents, identical or different, chosen from hydrogen and halogen atoms and hydrocarbon radicals having from 1 to 20 carbon atoms which may be a saturated or unsaturated, linear or branched acyclic aliphatic radical; a saturated, unsaturated, aromatic, monocyclic or polycyclic cycloaliphatic radical, optionally carrying a cyclic radical, aromatic or not, or of a saturated or unsaturated, linear or branched aliphatic radical in which the alkyl chain may be interrupted by one or more oxygen atoms and / or units

It is optionally substituted at the end of the chain by an aromatic or non-aromatic cyclic radical; said radicals possibly being substituted by one or more halogen atoms, preferably fluorine and / or one or more cyclic or acyclic, C1 to C6 alkyl radicals, or two of the groups A are linked together so as to constitute a cycloaliphatic radical as defined above, - Rf represents

(i) a halogen atom, preferably fluorine, ^• (ii) a poly- or perhalogenated alkyl radical whose polyhaloalkyl chain is optionally interrupted by one or more oxygen or sulfur atom (s), ( iii) a poly- or per-halogenated aryl radical, or

(iv) a radical chosen from R _A -CF ₂ , R _A -CF ₂ -CF ₂ -, R _A - CF ₂ -CF (CF ₃ ) -, CF ₃ -C (R _A ) F- and (CF ₃ ) R _A - with R _A having any of the meanings given below for R, it being understood that R _A represents neither a halogen atom nor a perhalogenated organic radical, - R represents S0 ₂ Rf or

(i) a halogen atom;

(ii) an alkyl chain, preferably C 1 to C 10, optionally interrupted by one or more oxygen or sulfur atom (s) or carbonyl function (s) and optionally substituted by one or more atom (s) d 'halogen or carboxyl or silyl group (s),

(iii) an alkenyl chain, preferably C ₂ to C 10, optionally interrupted by one or more oxygen or sulfur or with a carbonyl group and optionally substituted by one or more halogen atom (s) or carboxyl or silyl group (s);

(iv) an aryl group, preferably C ₆ to C1. ₂ , optionally substituted by one or more halogen atom (s) or alkyl or alkenyl group (s);

(v) an arylalkyl group, preferably from C ₇ to C ₁₅ , optionally substituted by one or more halogen atom (s);

(vi) an arylalkenyl group, preferably from C ₈ to C1 _.5 , optionally substituted by one or more halogen atom (s); (vii) -CO-Re or R _E group represents a halogen atom or an alkyl C l -C _4;

(viii) a group -O-CR _C RD-RB where R _B represents an alkylperfluorinated radical; and Rc and RD are, independently of each other, a radical chosen from (ii), (iii), (iv), (v) and (vi) above, it being understood that R _c and R _D do not carry halogen atom, provided that when n is equal to 1 and RfSO ₂ and R both represent a group -S0 ₂ CF ₃ then the three groups A do not simultaneously represent either a methyl radical or an isopropyl radical or if l 'one of the groups A represents a tert-butyl radical, then the other two groups A are different from a methyl radical and their derivatives.

For the purposes of the present invention, it is intended to cover under the term

"derivative" in particular the addition salts of the compounds of general formulas (I) and (la) obtained with organic or mineral acids. Among these derivatives, mention may also be made of structural isomers which may in particular exist with derivatives carrying bulky alkyl groups such as iPr and / or tBu groups at the level of the silicon atom.

In the particular case of compounds of general formula (la), the SiO form may be preferred over the SiN form represented by the general formula Ib

As substituents which may be present on the groups A, mention may in particular be made of halogen atoms, tertiary amine groups and ethers, esters and nitriles groups.

Of course, these substituents are chosen so as to remain inert under the reaction conditions.

The center or axis of chirality, present at the level of the structure of the claimed compounds, can be located at the level of one of the groups A, R or Rf. The silicon atom can also constitute a center of chirality.

According to a preferred embodiment of the invention, this center or axis of chirality is present at one of the groups A. It is more preferably a center of chirality carried by a carbon placed in the α position of the bound carbon to the silicon atom. The compounds of general formula I or la in which R and / or

Rf represent a halogen atom and in particular a fluorine atom which can be very reactive and therefore not very compatible with certain media, the present invention is easier to implement with compounds of general formula I or la in which R and / or Rf symbolize a different substituent of a halogen atom.

According to a more preferred variant of the invention, the claimed compounds correspond to the general formula (I) or (la) in which n and m are respectively equal to 1 and 3. According to a preferred variant of the invention, the compounds of general formula (I) or (la) have at least one and preferably two radicals S0 ₂ Rf, preferably represented by S0 ₂ CF ₃ , on their nitrogen atom.

The compounds of general formula (I) or (la) in which at least one of the groups A represents a saturated polycyclic, preferably C ₇ cycloaliphatic radical, carrying at least one alkyl chain, are very particularly suitable for the invention. preferably in C1 to Ce, optionally interrupted by one or more oxygen atoms and / or CO units and optionally substituted by or comprising at the end of the chain a group substituted or unsubstituted phenyl. According to a variant of the invention, the group or groups A representing at least one cycloalkyl or alkylcycloalkyl radical, unsaturated, saturated or aromatic carries (s) substituents capable of establishing internal chelations and / or of creating steric hindrance.

The compounds of general formula I or la in which A represents a cycloalkyl radical preferably cyclohexyl substituted, preferably in ortho, by either an aryl or alkylaryl group with the aryl unit being preferably chosen from phenyl radicals, thus being particularly advantageous. , α-naphthyle and β-naphthyle.

As representative examples of such substituents there may be mentioned tertiary alkyl groups, Ci to C ₆ alkoxy C _6, esters, tertiary amines, ethers, and nitriles.

Mention may more particularly be made, as representative of the compounds claimed, of the following compounds:

- N- (trimethylsilyl) -bis (pentafluorophenylsulfonyl) imide

- N- (trimethylsilyl) -bis (perfluorobutylsulfonyl) imide

- N- (dimethylpentafluorophenylsilyl) -bis (trifluoromethane sulfonyl) imide - dimethyl di [bis (thfluoromethanesulfonyl) imino] silane

- 1-methyl-1 - [bis (trifluoromethanesulfonyl) amino] silacyclobutane

(+) - N- [6,6-dimethyl-2-propylbicyclo [3.1 .1] hept-3-yl) - dimethylsilyl] bis (trifluoromethanesulfonyl) imide - (+) N - [(6,6-dimethyl-2 -phenethylbicyclo [3.1 .1] hept-3-yl) dimethylsilyl] bis (trifluoromethanesulfonyl) imide

(+) N-2- (methoxymethyl) -6,6-dimethylbicyclo [3.1 .1] hept-3-yl) dimethylsilyl] bis (trifluoromethanesuifonyl) imide

(+) - N- [2- (ethoxymethyl) -6,6-dimethylbicyclo [3.1 .1] hept-3- yl) dimethylsilyl] bis (trifluoromethanesulfonyl) imide

(+) - N- [2-benzyloxymethyl) -6,6-dimethylbicyclo [3.1 .1] hept-3- yl) dimethylsilyl] bis (trifluoromethanesulfonyl) imide S

- (+) - N- [2- (3,5-dimethylbenzyloxymethyl) -6,6-dimethylbicyclo [3.1.1] hept-3-yl) dimethylsilyl] bis (trifluoromethanesulfonyl) imide

(+) - N- [2- (benzoyloxymethyl) -6,6-dimethylbicyclo [3.1.1] hept- 3-yl) dimethylsilyl] bis (trifluoromethanesulfonyl) imide - (+) - N- {dimethyl [trans-2- (1-naphthyl) cyclohexyl] silyl} bis (trifluoromethanesulfonyl) imide and

- (-) - N- {dimethyl [trans-2- (1 -naphthyl) cyclohexyl] silyl} bis (trifluoromethanesulfonyl) imide.

The compounds of general formula (I) or (la) can be prepared by conventional synthetic routes.

Mention may in particular be made, as representative of these conventional methods of preparation, of those employing chlorotrialkylsilane or allyltrialkylsilane derivatives. The adjustment of these synthetic routes which are described in the literature (Ghosez et al. Tetrahedron Lett. 1997, 38, 5497; Robertson et al. Tetrahedron Lett. 1998, 39, 3215; Schreeve et al. Inorg. Chem. 1994 , 33, 3281), the preparation of the claimed compounds falls within the competence of those skilled in the art.

The present invention also relates to a new route for the synthesis of the compounds of general formula (I).

More specifically, it relates to a process useful for preparing compounds of general formulas (I) and (la) as defined above, characterized in that at least one compound of general formula II or III is reacted < A) ₃ IF— / \ <"

with at least one compound of general formula IV

in which, A, R, Rf, y and z are as defined above and in that said compound of general formula I is recovered.

This new synthetic route is particularly advantageous with regard to those already available and in particular that using the allylsilane derivative mentioned above because, unlike the synthetic route involving the allylsilane derivative, it does not generate a secondary product. For example, while the HNTf ₂ reacts with the propene released during the reaction with the allylsilane derivative, the HNTf ₂ does not react with the benzene formed during the claimed process using the compound II.

In fact, the operating conditions used to carry out the synthesis of the compounds of general formula I according to the claimed process or one of the two other conventional routes are generally dictated by the chemical nature of the starting compounds. Generally, two equivalents of the compound of formula (II) or (III) are brought together for one equivalent of compound of formula (IV).

The reaction can be carried out in an organic solvent of dichloromethane or 1,2-dichloroethane type. The temperature is between 0 ° C and the reflux of the solvent, and is preferably close to or equal to room temperature. The reaction is carried out for a sufficient time to obtain the transformation of the product of formula (II) or (III) into the product of formula (I). The final compound is isolated by conventional techniques from the reaction medium.

The present invention also relates to the use of compounds of general formula (I) or (la) as Lewis acid.

As mentioned above, the compounds of general formula I prove to be particularly effective in catalyzing reactions of the Diels-Alder reactions, carbonyl allylations, ene reactions, Prins reactions, and Michael additions. In particular, the claimed compounds having a center or axis of chirality prove to be particularly advantageous for inducing asymmetric synthesis and therefore favoring the synthesis of an enantiomer.

In the examples given below, it is in particular shown that the presence of a compound of general formula I such as (+) N-2- (methoxymethyl) -6,6-dimethylbicyclo [3.1 .1] hept-3 -yl) dimethylsilyl] bis (trifluoromethanesulfonyl) imide in a Diels-Alder reaction between a cyclopentadiene and methyl acrylate leads to the expected condensation product with an enantiomeric excess of 54%.

The compounds of general formula I can be introduced as they are into the reactions to be catalyzed or be generated therein in situ.

According to this last variant, they are generated in the reaction medium, prior to carrying out the desired reaction, for example from Diels-Alder, according to one of the 3 synthetic routes mentioned above.

Generally, these reactions are carried out in solvents such as toluene, benzene, dichloromethane, dichloroethane, and acetonithle.

Thus with (+) N-2- (methoxymethyl) -6,6- dimethylbicyclo [3.1 .1] hept-3-yl) dimethylsilyl] bis (thfluoro-methanesulfonyl) imide, better yields are obtained for acrylates substituted in alpha or beta position with a chlorinated solvent. Conversely, aromatic solvents, of the toluene type, favor high enantiomeric excesses.

Furthermore, it may prove advantageous to combine with the catalyst according to the invention, a basic compound. The presence of this basic compound is in fact more particularly desirable when there is a risk of potential degradation of one of the reactants, diene for example. This degradation can in particular be induced by the residual traces of the acid bis (trifluoromethanesulfonyl) imide which served to synthesize the compound of general formula I.

Particularly suitable as a base are tertiary amines or pyridine derivatives which are sufficiently hindered to selectively complex. the proton with respect to the group (A ₃ ) Si. As such, 2,6-bis (tbutyl) -4-methylpyridine is particularly advantageous.

The compound of general formula I is used as a Lewis acid catalyst in an amount sufficient to start the expected reaction.

By way of non-limiting example of the invention, it can be used at a rate of 0.5% to 100 mol% expressed relative to the faulty reagent (often the dienophil).

More preferably, it is present in an amount of 5 to 20% and more particularly in an amount of about 10%.

The examples given below are presented by way of illustration and without limitation of the present invention.

EXAMPLE 1 Preparation of N- (trimethylsilyl) -bis (pentafluorophenylsulfonyl) imide: C ₆ F ₅ Me ₂ SiNTf ₂ .

_{+ AgC |}

2.5 g (6.443 mmol; 1 eq.) Of bis (trifluoromethanesulfone) imide of silver is introduced into a 50 ml flask, fitted with a frit in its wall, with a magnetic bar and under argon. 4 ml dry dichloromethane. The mixture is stirred vigorously to obtain a white suspension. 1.334 ml (1.847 g; 7.087 mmol; 1.1 eq.) Of chiorodimethyl (pentafluorophenyl) silane are added and the reaction continued overnight, protected from light and at room temperature. The resulting suspension is filtered under argon through the frit incorporated in the wall of the flask. The dichloromethane is evaporated in vacuo and the residue is distilled under reduced pressure (120-130 ° C / 10-3mbar). 1.697 g of a colorless liquid are obtained. EXAMPLE 2

Preparation of dimethyl di [bis (trifluoromethanesulfonyl) iminojsilane: Me ₂ SiN ₂ Tf.

In a 100 ml monocol fitted with a magnetic bar, a condenser surmounted by a silica gel tube and under argon, 4 g (14.22 mmol; 2 eq.) Of bis (trifluoromethanesulfone) imide are introduced and covered 16 ml of dry 1, 2-dichloroethane. The mixture is heated to reflux and 1.299 ml (998 mg; 7.113 mmol; 1 eq.) Of diallyldimethylsilane are added slowly through the condenser. The mixture turns pale yellow and is kept at reflux overnight (18h). The solvent is evaporated and the residue is distilled vertically through a small flask. 2.551 g of a yellow viscous liquid, which becomes cloudy on collection (98 ° C / 10-3 mbar), are collected with a yield of 58%.

EXAMPLE 3 Preparation of 1-methyl-1- [bis (thfluoromethanesulfonyl) aminojsilacyclo-butane: MeNTf ₂ SCB.

NTf _{2 +} AgCI

2.5 g (6.443 mmol; 1 eq.) Of bis (trifluoromethanesulfone) imide of silver and then 5 g are introduced into a 50 ml flask, fitted with a frit in its wall, with a magnetic bar and under argon. ml dry dichloromethane. The mixture is stirred vigorously to obtain a white suspension. 1 g (8.288 mmol; 1.28 eq.) Of 1-chloro-1-methylsilacyclobutane are added and the reaction is continued overnight, protected from light and at room temperature (18 h). The resulting suspension is filtered. The dichloromethane is evaporated in vacuo and the residue is distilled under pressure reduced (90-100 ° C / 2.8 mbar). 1.641 g of a golden liquid are obtained with a yield of 69.7%.

EXAMPLE 4 Preparation of N- (thmethylsilyl) -bis (pentafluorophenylsulfonyl) imide: TMSNPf ₂ .

1.5 g (3.143 mmol; eq.) Of bis (pentafluorophenylsulfone) imide are introduced into a 25 ml monocol fitted with a magnetic bar, a condenser topped with a silica gel tube and under argon. The flask is cooled in an ice bath and 6 ml (4.314 g) of allyltrimethylsilane are added quickly. The reaction is heated to reflux of the allyltrimethylsilane until the solid has completely dissolved. Upon cooling, a white solid crystallizes. The dissolution / recrystallization process is repeated twice. The crystals are filtered under argon, transferred under an inert atmosphere to a flask and then dried at the pump. 1.362 g of white crystals are collected with a yield of 83%.

EXAMPLE 5

Preparation of N- (trimethylsilyl) -bis (perfluorobutylsulfonyl) imide: (TMSNf ₂ ).

In a 25 ml monocol fitted with a magnetic bar, a condenser surmounted by a silica gel tube and under argon, 1.826 g (3.143 mmol; 1 eq.) Of bis (nonafluorobutylsulfone) imide are introduced. The flask is cooled in an ice bath and 6 ml (4.314 g) of allylt methylsilane are added quickly. The reaction is heated to reflux of the allyltrimethylsilane until the solid has completely dissolved. The reaction is continued for one hour at room temperature and then the excess of allyisilane is evaporated in vacuo. A pale yellow oil is obtained corresponding to the expected silylated product (1.953 g) with a yield of 95%.

EXAMPLE 6 Preparation of N- (trimethylsilyl) -bis (perfluorobutylsulfonyl) imide:

(TMSNf ₂ ).

- "^ SiMeg or

In a 25 ml monocol fitted with a magnetic bar, a condenser topped with a silica gel tube and under argon, 200 mg

(344.1 μmoles; 1 eq.) Of bis (nonafluorobutylsulfone) imide are introduced and covered with CDCI ₃ sec. 106.2 μl (68.98 mg; 688.2 μmoles; 2 eq.) Of vinyltrimethylsilane or 118.4 μl (103.4 mg; 688.2 μmoles; 2 eq.) Of phenyltrimethylsilane are added quickly. The reaction is heated at reflux for 30 minutes. The production of TMSN (S0 ₂ CF ₉ ) ₂ is verified in both cases by NMR

EXAMPLE 7

Preparation of chloro (6,6-dimethyl-2-propylbicyclo [3.1.1j hept-3- yl) dimethylsilane.

In a 100 ml three-necked flask fitted with a magnetic bar, a silica gel tube and under argon, 2.915 g (7.853 mmol; 1.5 eq.) Of (ethyl) triphenylphosphonium bromide are introduced and covered with 25 ml of THF sec. 927.6 mg (7.853 mmol; 1.5 eq.) Of potassium t-butoxide are added and the reaction is continued for 60 minutes. A solution of 1.5 g

(5.235 mmol; 1 eq.) Of (6,6-dimethyl-2-formylbicyclo [3.1.1] hept-3- yl) dimethylphenyisilane in 5 ml of dry THF are added dropwise slowly. The reaction is continued for 15 hours at room temperature. The reaction is stopped by adding 20 ml of a 1N aqueous solution in

NH ₄ OAc. The phases are decanted, the aqueous phase is washed twice with

20 ml of ether. The organic phases are dried over MgSO and filtered. The solvents are evaporated in vacuo.

The crude is a white / yellow solid which is taken up in 80 ml of hexaπe and filtered to remove the triphenylphosphine oxide. The filtrate is evaporated and quickly filtered on a column of flash silica (pure EP). We collect a colorless oil corresponding to the mixture of cis and trans olefins which is directly placed in a flask containing 520 mg (488.6 μmoles; 0.0933 eq.) of Palladium on activated carbon (10%) and 20 ml of AcOEt. The solution is purged 3 times with nitrogen then 3 times with hydrogen with intense stirring. The reaction is placed under a hydrogen atmosphere and intense stirring for 18 h. The suspension is filtered through celite and the AcOEt is evaporated in vacuo.

0.967 g of a colorless liquid are collected corresponding to a mixture of the reduced product (+/- 70%) and the reduced product having lost the Me ₂ SiPh group (+/- 30%).

The expected reduced product, (6,6-dimethyl-2-propylbicyclo [3.1.1] hept-3-yl) -dimethylphenylsilane, is separated by flash column with pure petroleum ether (0.784 g) with a yield of 61.44%.

In a 25 ml monocol with an empty sillicagel tube and a magnetic bar, 900 mg (2.994 mmol; 1 eq.) Of (6,6-Dimethyl-2-propylbicyclo [3.1.1] hept-3 -yl) -dimethylphenylsilane are introduced and covered with 6 ml of CHCl ₃ . The solution is placed under an HCl atmosphere for 2 days. The mixture is transferred to a horizontal distillation apparatus for Kugeirhor and the solvents are evaporated at the pump. Silyl chloride is distilled at 125 ° C under 6x10 ^"3 mBar. 0.520 g of a colorless liquid are collected.

The corresponding trialkylsilyl-bis (trifluoromethanesulfonyl) imide derivative is obtained by reaction of this chlorinated compound with the silver bis (trifluoromethane sulfone) imide according to the protocol described in Example 1.

EXAMPLE 8

Preparation of chloro (6,6-dimethyl-2-phenethyl-bicyclo [3.1.1] hept-3-yl) dimethylsilane.

This compound is prepared according to the reaction scheme described in Example 6 by substituting for ethyl (triphenylphosphonium) bromide, (benzyl) triphenyl phospholiphonium chloride. The reaction is carried out according to the following operating protocol.

1.5 g (3.857 mmol; 1.5 eq.) (Benzyl) -triphenylphosphonium chloride are introduced and covered in a 100 ml three-necked flask fitted with a magnetic bar, a silica gel tube and under argon 25 ml of dry THF. 455.6 mg (3.857 mmol; 1.5 eq.) Of potassium t-butoxide are added and the reaction is continued for 60 minutes. A solution of 0.736 g (2.571 mmol; 1 eq.) Of (+) - (6,6-dimethyl-2-formylbicyclo [3.1.1] hept-3- yl) dimethylsilane in 5 ml of dry THF is added dropwise slow drop. The reaction is continued for 6 hours at RT. The reaction is stopped by adding 20 ml of a 1N aqueous NH ₄ OAc solution. The phases are decanted, the aqueous phase is washed twice with 20 ml of ether. The organic phases are dried over MgSO and filtered. The solvents are evaporated in vacuo.

The crude is a white solid which is taken up in 50 ml of hexane and filtered to remove the triphenylphosphine oxide. The filtrate is evaporated and chromatographed on a column of flash silica (pure hexane). 0.645 g of a colorless oil are collected, corresponding to the mixture of cis and trans olefins.

In a 50 ml three-necked flask fitted with a magnetic rod and two taps, 1.46 g (4.048 mmol; 1 eq.) Of (+) - (6,6-dimethyl-2-styryl- bicyclo [3.1.1] hept-3-yl) dimethylphenylsilane (cis-trans mixture) are introduced and covered with 15 ml of ethyl acetate. 403.5 mg (379.1 μmoles; 0.0936 eq.) Of Palladium on activated carbon (10%) are added and the suspension purged 3 times with nitrogen then 3 times with hydrogen with vigorous stirring. The reaction is maintained under a pressure of 1 atm of hydrogen overnight (15 h). The suspension is filtered through cellite and the solvents are evaporated. The hydrogenated product is obtained quantitatively in the form of a colorless oil.

The product can be purified of some impurities by rapid flash with pure petroleum ether. In a 50 ml monocolor flask, 1.35 g (3.722 mmol; 1 eq.) Of (+) - (6,6-Dimethyl-2-phenethyl-bicyclo [3.1.1] hept-3-yl) -dimethylphenylsilane are introduced and covered with 15 ml of CHCI ₃ treated without alcohol. The mixture is placed under an HCl atmosphere for 3 days. The mixture is then concentrated at the pump. The product is distilled at 135 ° C under 6 x 10 ^"3 mbar to obtain a colorless liquid (0.940 g).

The corresponding trialkylsilyl-bis (trifluoromethanesulfonyl) imide derivative is obtained by reaction of this chlorinated compound with bis (silver trifluoromethane) imide according to the protocol described in Example 1.

EXAMPLE 9

Preparation of (+) - chloro [2- (methoxymethyl) -6,6- dimethylbicyclo [3.1.1] hept-3-yl-dimethylsilane.

1.33 g (27.72 mmol; 2 eq.) Of sodium hydride are introduced into a 50 ml three-necked flask fitted with a magnetic bar, a condenser and under argon. The NaH is washed with 4 ml of dry THF and then covered with 12 ml of THF. The suspension is heated to 45 ° C and a mixture of 4 g (13.86 mmol; 1 eq.) Of (+) - [6,6-dimethyl-2-hydroxymethylbicyclo [3.1 .1] hept-3-yl] dimethylphenylsilane and 2.589 ml (5.903 g; 41.59 mmol; 3 eq.) of iodomethane is added slowly. The reaction is continued for 2 h at 50 ° C. and followed by TLC. We no longer see any changes, but alcohol remains. Half a spatula of NaH and 0.3 ml of Mel are added and the mixture stirred for an additional hour at 50 ° C. 10 ml of water are added and the organic phase decanted. The aqueous phase is washed with 3 times 30 ml of CH ₂ CI ₂ . The organic phases are mixed, dried over MgSO and filtered. The solvents are evaporated in vacuo. The crude is chromatographed on a column of flash silica (EP / Et ₂ 0 97/3). The expected ether is collected in the form of a colorless oil.

1.14 g (3.768 mmol; 1 eq.) Of (+) - [2- (methoxymethyl) -6 are introduced into a 50 ml three-necked flask fitted with a magnetic bar, a silica gel tube and under argon , 6-dimethylbicyclo [3.1 .1] hept-3-yl] dimethylphenylsilane which is covered with 15 ml of CHCl ₃ PA. HCI is bubble for 1 hour 30 minutes then the reaction is maintained under an atmosphere of HCI. The reaction is continued for 1, 5 days (30-35 h) at room temperature and followed regularly by cc. There is a slow disappearance of the reagent. The solvents are evaporated at the pump and the crude oil is purified by fractional distillation at 95-100 ° C under 8.8x10 ^"3 mBar. 0.694 g of a pale yellow liquid which crystallizes cold is collected. The trialkylsilyl-bis derivative ( trifluoromethanesulfonyl) corresponding imide is obtained by reaction of this chlorinated compound with bis (trifluoromethane sulfone) silver imide according to the protocol described in Example 1. EXAMPLE 10

Preparation of (+) - chioro [2-ethoxymethyl) -6,6- dimethylbicyclo [3.1.1] hept-3-yl] dimethylsiiane.

This compound is prepared according to the reaction scheme presented in Example 9 and by substituting methyl iodide with bromoethane. The procedure is as follows.

499 mg (15.59 mmol; 3 eq.) Of sodium hydride and then 5 ml of THF are introduced into a 50 ml three-necked flask fitted with a magnetic bar, a condenser and under argon. The suspension is heated to 40 ° C and a mixture of 1.5 g (5.199 mmol; 1 eq.) Of (+) - [2- (hydroxymethyl) -6,6- dimethylbicyclo [3.1.1] hept-3- dimethylphenylsilane and 3.167 ml (4.624 g; 41.59 mmol; 8 eq.) of bromoethane in 10 ml of THF are added dropwise slowly. The reaction is continued for 48 hours at 40 ° C. and followed by TLC (EP / Et ₂ 0 8/2). Half a spatula of NaH is added during heating. 10 ml of water are added and the organic phase decanted. The aqueous phase is washed with 3 times 30 ml of CH2CI ₂ . The organic phases are mixed, dried over MgS0 and filtered. The solvents are evaporated in vacuo. The crude is chromatographed on a column of flash silica (EP / Et ₂ 0 98/2). 1.109 g of expected pether are collected in the form of a colorless oil. 935 mg (2.637 mmol; 1 eq.) Of (+) - [2- (ethoxymethyl) -6.6 are introduced into a 50 ml three-necked flask fitted with a magnetic bar, a silica gel tube and under argon -dimethylbicyclo [3.1 .1] hept-3-yl] dimethylphenylsilane which is covered with 15 ml of CHCl ₃ PA. The reaction is maintained under HCl pressure. The reaction is continued for 3 days at AT and followed regularly by tcm. There is a slow disappearance of the reagent. The solvents are evaporated at the pump and the crude is purified by fractional distillation at 95-100 ° C under 3x10 ^"2 mbar. 0.556 g of a colorless liquid is collected. The corresponding trialkylsilyl-bis (trifluoromethanesulfonyl) imide derivative is obtained by reaction of this chlorinated compound with the silver bis (trifluoromethane sulfone) imide according to the protocol described in Example 1.

EXAMPLE 11

Preparation of (+) - chloro [2- (benzyloxymethyl) -6,6- dimethylbicyclo [3.1.1] hept-3-yl] dimethylsilane.

374.3 mg (7.798 mmol; 1.5 eq.) Of sodium hydride are introduced into a 50 ml three-necked flask fitted with a magnetic bar, a condenser and under argon. The NaH is washed with 4 ml of dry THF and then covered with 6 ml of THF. The suspension is heated to 45 ° C. and a mixture of 1.5 g (5.999 mmol; 1 eq.) Of (+) - 3-dimethylphenylsilyl-2,3-dihydromyrtenol and 927.5 μl (1.333 g; 7.798 mmoles; 1.5 eq.) of benzyl bromide in 10 ml of THF is added slowly dropwise. The reaction is continued for 3 h at 70 ° C. and followed by TLC. We no longer see any changes, but alcohol remains. Half a spatula of NaH and 0.5 ml of PhCH ₂ Br are added and the mixture stirred for an additional hour at 70 ° C. 10 ml of water are added and the organic phase decanted. The aqueous phase is washed with 3 times 30 ml of CH ₂ CI ₂ . The organic phases are mixed, dried over MgSO and filtered. The solvents are evaporated in vacuo. The crude is chromatographed on a column of flash silica (EP / Et ₂ O 98/2). 1.377 g of the expected ether are collected in the form of a colorless oil. 1.34 g (3.539 mmol; 1 eq.) Of (+) - [2- (benzyloxymethyl) -6 are introduced into a 50 ml three-necked flask fitted with a magnetic bar, a silica gel tube and under argon , 6-dimethylbicyclo [3.1.1) hept-3-yl] dimethylphenylsilane which is covered with 15 ml of CHCl ₃ PA. The reaction is maintained under HCI pressure by means of a triple balloon filled with HCI. The reaction is continued 2.5 days at RT and monitored regularly by TLC. There is a slow disappearance of the reagent. The solvents are evaporated under vacuum and the crude product is purified by fractional distillation at 175 ° C under 2x10 ^"3 mBar. 1.032 g of a colorless liquid is collected. The corresponding trialkyisilyl-bis derivative (trifluoromethanesuIfonyl) imide is obtained by reaction of this compound chlorinated with bis (trifluoromethane sulfone) silver imide according to the protocol described in Example 1.

EXAMPLE 12

Preparation of (+) - chloro [2- (3,5) dimethylbenzyloxymethyl) -6,6- dimethylbicyclo [3.1.1] hept-3-yl] dimethylsilane.

The procedure is carried out according to the reaction scheme and the procedure described in example 11.

In this particular case, 3.5 dimethylbenzyl bromide is used in place of benzyl bromide.

1.5 g (5.199 mmol; 1 eq. Of (+) - [2- (hydroxymethylbicyclo [3.1.1] hept-3-yl] dimethylphenylsilane) and 1.373 g (6.758 mmol; 1.3 eq.) .) 3,5-dimethylbenzyl bromide. At the end of the synthesis, 0.962 g of a colorless liquid are collected.

EXAMPLE 13

(+) - chloro [2- (benzoyloxymethyl) -6,6- dimethylbicyclo [3.1.1] hept-3-yl] dimethylsilane benzoate.

In a 100 ml three-necked flask fitted with a condenser and a magnetic bar, 1.6 g (5.545 mmol; 1 eq.) Of (+) - [2- (hydroxymethyl) -6,6- dimethylbicyclo [3.1. 1] hept-3-yl] dimethylphenylsilane and 1.054 ml (1.008 g;

8.318 mmol; 1.5 eq.) Of N, N-dimethylaniline are introduced and covered with

8 ml of dry ether. 965.6 μl (1.169 g; 8.318 mmol; 1.5 eq.) Of benzoyl chloride are added together with a few DMAP crystals. The mixture is stirred overnight at room temperature then 1 h 30 at 45 ° C (addition of 10 ml of ether). 15 ml of water are added, the phases are decanted and the organic phase washed 2 times with successively 20 ml of 5% H ₂ S0 solution and saturated NaHCO ₃ . The organic phase is dried over MgSO and filtered, the solvents are evaporated in vacuo. The crude is chromatographed on a flash silica column (EP / Et ₂ O, 5/2). 2.02 g of a colorless liquid corresponding to the benzoyl product are collected.

In a 50 ml monocol fitted with an empty silica gel tube and a magnetic bar, 1.6 g (4.075 mmol; 0.734 eq.) Of benzoate of 8- (dimethyiphenylsilanyl) -6,6-dimethylbicyclo [3.1.1] hept-2-yl-methyl are introduced and covered with 15 ml of CHCl ₃ treated without EtOH. The reaction is placed under gaseous HCl 4.5 days at RT then 24 h at 60 ° C. It is noted that the reaction no longer evolves despite the heating, there always remains the starting silyl. The solvent is evaporated in vacuo. Silyl chloride is separated from its precursor by fractional distillation at 170 ° C under 6.3 x 10 ^-3 mbar. 0.574 g of silyl chloride is collected.

EXAMPLE 14

Trans-1-dimethylphenylsilyl-2-alpha-napthylcvclohexenone. 1) Synthesis of 2-alpha-naphthylcvclohexenone

Enolate preparation

In a three-necked flask of 500 fitted with a magnetic bar and under argon, 5,499 ml (3.97 g; 39.24 mmol; 1.1 eq.) Of diisopropylamine are introduced and covered with 120 ml of dry THF. 19.62 ml (13.59 g; 39.24 mmol; 1.1 eq.) Of butyllithium, 2.5M in solution in hexane are added at 0 ° C and the mixture is stirred for 10 minutes. The reaction mixture is cooled to - 78 ° C and 4 g (35.67 mmol; 1 eq.) Of 2,3-epoxy-cyclohexan-1-one are added dropwise.

Preparation of the naphthyllithian

In a 500 ml three-necked flask, 9,921 ml (14.77 g; 71.34 mmol; 2 eq.) Of 1-bromonaphthalene are introduced and covered with 140 ml of THF. The mixture is cooled to -78 ° C and 83.93 ml (142.6 mmol; 4 eq.) Of -BuLi 1.5M are added slowly using an addition funnel. The reaction is continued for 30 minutes at -78 ° C then 10 minutes at 0 ° C. The lithian solution is a pale yellow suspension

Addition of naphthyllithian on enolate.

The naphthyllithian solution is cannulated at -78 ° C on the enolate previously cooled to this temperature. The mixture is then placed in a bath at -23 ° C and stirred at this temperature for 2 hours. The reaction is stopped by adding 40 ml of an aqueous NH ₄ Cl solution at 0 ° C. The phases are decanted, the aqueous phase is washed with 3x100ml of ether. The organic phases are combined, washed with 2 × 80 ml of an aqueous HCl solution and then with 100 ml of a saturated NaHCO ₃ solution. The organic phase is dried over MgSO ₄ , filtered and the solvents evaporated under vacuum.

Dehydration of alcohol.

The reaction crude thus obtained is placed in a 250 ml monocol fitted with a dean-stark and a magnetic bar. 150ml of toluene and a spatula of APTS are added. The mixture is heated at reflux for 1 h. 60 ml of a saturated NaHCO ₃ solution are added and the phases are decanted, the aqueous phase is washed with 3 × 100 ml of ether. The organic phases are combined, dried over MgSO ₄ , filtered and the solvents evaporated in vacuo. The crude reaction product is recrystallized from an EP / AcOEt mixture. The mother liquors are recovered, evaporated and are purified on flash silica column (EP / AcOEt 8/2). A total of 4.886 g (62% over the two stages) of the expected product is collected in the form of colorless crystals.

2. Synthesis of trans-2-alpha-naphthyl-3-dimethylphenylsilylcvclohexanone

Cuprate formation:

576.7 μl (1.684 g; 18.8 mmol; 1.1 eq.) Of CuCN are introduced into a 250 ml three-necked flask fitted with a magnetic bar and under argon, which is covered with 40 ml of dry THF and the mixture is cooled to 0 °. vs. 37.6 ml (37.6 mmol; 2.2 eq.) Of Phenyldimethylsilyl lithium are added via a syringe. The mixture is stirred for 20 minutes at 0 ° C.

Addition on enone:

The reaction mixture is cooled to -25 ° C and 3.8 g (17.09 mmol; 1 eq.) Of 2-naphthylcyclohexenone are added to the syringe. The reaction is continued for 2 h 30 min at -30 ° C and 2 h at 0 ° C. The reaction is stopped by adding 40 ml of a saturated NH ₄ Cl solution. The aqueous phase is washed with 3 × 100 ml of ether and the organic phases rewashed with a little solution saturated with NH CI. The organic phases are combined, dried over MgSO ₄ and the solvents evaporated under vacuum. The reaction crude is chromatographed on a column of flash silica (EP / Et ₂ O 85/15). The product collected is contaminated with dimethyliphenylsilanol, the latter is distilled at 110 ° C. under 2.10 ^"2 mmHg. 1.4 g (23%) of a colorless glue corresponding to the addition product are collected. 2 enantiomers are separated on preparative HPLC (column AD, hexane / ipr 92/8).

3) Synthesis of trans-2-alpha-naphthyl-3-dimethylphenylsilylcvclohexanone tosylhvdrazone

In a 100 ml monocol fitted with a magnetic bar, a condenser and under argon, 714 mg (1.991 mmol; 1 eq.) Of MA091 and 407.9 mg (2.19 mmol; 1.1 eq.) Of N-paratoluenesulfonylhydrazine are introduced and covered with 10 ml of MeOH. The mixture is heated at 50 ° C for 60 minutes. During this time, the hydrazone precipitates out of the reaction mixture. The latter is cooled in an ice bath, filtered and the precipitate is washed with MeOH. A second harvest can be obtained by evaporating the MeOH and adding 1 ml of MeOH, heating to 60 ° C for 15 minutes and filtration. The white solid is dried under vacuum to provide 1.068 g (quantitative) of the expected hydrazone.

4) Synthesis of trans-1-dimethylphenvisilyl -2-alpha-naphthylcvclohexane

In a 5 ml monocol fitted with a magnetic bar and a condenser, 100 mg (189.8 μmoles; 1 eq.) Of the hydrazone previously formed are introduced and a solution of 55.07 μl (59.64 mg; 949.1 μmoles; 5 eq. .) sodium cyanoborohydride and 44.45 μl (129.3 mg; 949.1 μmoles; 5 eq.) of zinc chloride in 1 ml of a 1: 1 MeOH / EtOH mixture is introduced at room temperature. The reaction is heated to 60 ° C and the reaction is monitored by TLC. The alcohols are evaporated under vacuum and the residue taken up with 1 ml of saturated solution of K ₂ CO ₃ , 1 ml of water and 2 ml of CH ₂ CI ₂ . The aqueous phase is washed with 2x5 ml of CH ₂ CI ₂ . The organic phases are combined, dried over MgSO, filtered and the solvents are evaporated in vacuo. The reaction crude is chromatographed on a column of flash silica (pure hexane). 0.032g (49%) of the oxygenated product are obtained in the form of a colorless oil.

EXAMPLE 15

Evaluation of catalysts according to the invention through the cycloaddition of cyclopentadiene with methyl acrylate.

These cyclo-additions were carried out in the presence of 10 mol% of the catalyst, at -78 ° C in toluene.

Table 1 reports the results.

Table 1

It should be noted that the catalyst according to the invention is particularly effective in the particular case of cyclopentadiene. An enantiomeric excess of 54% is obtained.

EXAMPLE 16

Evaluation of (+) N-2- (methoxymethyl) -6,6-dimethylbicyclo [3.1.1] hept-3-yl) dimethylsilyl] bis (trifluoromethanesulfonyl) imide as catalyst for the Diel and Alders reactions.

Cycloadditions of methyl acrylate were carried out with various dienes. Certain cycloadditions were carried out in the presence of 2,6-bis (f butyl) -4-methylpyridine (BTBMP). The catalyst is prepared in situ by the combination of precursor silyl chloride and AgNTf ₂ .

Table 2 appearing below gives an account of the operating conditions selected, of the general formula of the dienes involved in the cycloadditions as well as the enantiomeric excesses obtained. Table 2

EXAMPLE 17

In this test, cyclopentadiene is used as diene and the chemical nature of the dienophile is varied.

Table 3 below shows the operating conditions used as well as the results obtained.

Table 3

EXAMPLE 18

Evaluation of -N- {dimethyl [trans-2- (1-naphthyl) cyclohexyl] silyl} bis (trifluoromethanesulfonyl) imide as catalyst for the Diel and Alders reactions.

The protocol followed is schematized as follows

In a 25ml bicol fitted with a magnetic bar, a silica gel tube and under argon, 45.91 mg (133.2 μmol; 0.15 eq.) Of trans-1-dimethylphenylsilyl- 2-alphanaphthylcyclohexane are introduced and 0.22 ml of a 0.405M solution of dry ₂ hNTf in dichloromethane are added. 0.5 ml of dry dichloromethane are added and the reaction is stirred at room temperature for 1 h. 36.48 mg (177.6 μmoles; 0.2 eq.) Of 2,6-di-tert-butyl-4-methylpyridine are added together with 1.5 ml of dry dichloromethane. The mixture is cooled to -100 ° C. and 80 μl (76.48 mg; 888.3 μmoles; 1 eq.) Of methyl acrylate are introduced followed by 292.8 μl (234.8 mg; 3,553 mmoles; 4 eq.) Of cyclopentadiene. The reaction is continued for 1 h 30 min at -100 ° C. and then stopped at low temperature by the addition of 1 ml of a saturated solution of (NH ₄ ) ₂ CO ₃ . The aqueous phase is extracted with 3 × 5 ml of CH ₂ CI ₂ . The organic phases are combined, dried over MgSO and filtered.

A conventional chromatograph allows the product to be isolated with a yield of 95%.

Enantiomeric excess measured on chiral GC (chromasil CP-DEX-CB from Chrompak): 59%.

The protocol was reproduced by modifying certain operating parameters. These modifications and the results obtained are presented in Table 4 below.

Table 4

Claims

1. Compound of general formula I

in which - y represents an integer equal to 1 or 2 and z zero or 1 with the sum of y + z being equal to 2, Rf represents

(i) a halogen atom, preferably fluorine, (ii) a poly- or perhalogenated alkyl radical whose polyhalogenoalkyl chain is optionally interrupted by one or more oxygen or sulfur atom (s),

(iii) a poly- or per-halogenated aryl radical, or (iv) a radical chosen from R _A -CF ₂ , R _A -CF ₂ -CF ₂ -, R _A - CF ₂ -CF (CF ₃ ) -, CF ₃ -C (R _A ) F- and (CF ₃ ) R _A - with R _A having any one of the meanings given below for R, it being understood that RA represents neither a halogen atom nor a radical polyhalogenated organic,

R represents Rf or

(i) an alkyl chain optionally interrupted by one or more oxygen or sulfur atom (s) or carbonyl function (s) and optionally substituted by one or more halogen atom (s) or carboxyl or silyl group (s) ,

(ii) an alkenyl chain optionally interrupted by one or more oxygen or sulfur atom (s) or carbonyl function (s) and optionally substituted by one or more halogen atom (s) or carboxyl or silyl group (s) ;

(iii) an aryl group optionally substituted by one or more halogen atom (s) or an alkyl or alkenyl group; (iv) an arylalkyl group optionally substituted by one or more halogen atom (s);

(v) an arylalkenyl group optionally substituted by one or more halogen atom (s); (vi) -CO-RE group _E with R representing a halogen atom or an alkyl C l -C _4;

(vii) a group -O-CR _C RD-RB with R _B representing an alkylperfluorinated radical; and R _c and RD being independently of each other a radical chosen from (i), (ii), (iii), (iv) and (v) above, it being understood that Rc and R _D do not carry halogen atom. n is an integer equal to 1 or 2, m is an integer equal to 2 or 3 with the sum n + m being equal to 4,

A represents 2 or 3 identical or different substituents chosen from hydrogen and halogen atoms and hydrocarbon radicals having from 1 to 20 carbon atoms which may be an acyclic saturated or unsaturated, linear or branched aliphatic radical; a saturated, unsaturated, aromatic, monocyclic or polycyclic cycloaliphatic radical optionally carrying a cyclic radical, aromatic or not, or a saturated or unsaturated aliphatic radical, linear or branched with the alkyl chain which can be interrupted by one or more oxygen atoms and / or units

^ and where appropriate substituted by a cyclic substituent, aromatic or not; said radicals possibly being substituted by one or more halogen atoms, preferably fluorine and / or one or more alkyl radicals in d to Ce or two of the groups A are linked together so as to constitute a cycloaliphatic radical such as defined above, provided that when z = 0 and n is equal to 1 and Rf represents a radical CF ₃ then the three groups A do not simultaneously represent either a methyl radical or an isopropyl radical or if one of the groups A represents a tert-butyl radical, then the two other groups A are different from a methyl radical, with said compound having at least one center or axis of chirality at the level of its structure, and its derivatives.

2. Compound according to claim 1, characterized in that it corresponds to the general formula la

in which

- n is an integer equal to 1 or 2,

- m is an integer equal to 2 or 3 with the sum n + m being equal to 4, - A represents 2 or 3 substituents, identical or different, chosen from hydrogen and halogen atoms and hydrocarbon radicals having 1 to 20 carbon atoms which may be a saturated or unsaturated, linear or branched acyclic aliphatic radical; a saturated, unsaturated, aromatic, monocyclic or polycyclic cycloaliphatic radical, optionally carrying a cyclic radical, aromatic or not, or of a saturated or unsaturated, linear or branched aliphatic radical, the alkyl chain of which may be interrupted by one or more oxygen atoms and / or units

|| and optionally substituted with an aromatic or non-aromatic cyclic radical; said radicals may optionally be substituted by one or more halogen atoms, preferably fluorine and / or one or more cyclic or acyclic alkyl, C l -C _6, or two of the groups A are linked together so as in constituting a cycloaliphatic radical as defined above, Rf represents (i) a halogen atom, preferably fluorine,

(ii) a poly- or perhalogenated alkyl radical whose polyhalogenoalkyl chain is optionally interrupted by one or more oxygen or sulfur atom (s), (iii) a poly- or per-halogenated aryl radical, or

(iv) a radical chosen from RA-CF ₂ , R _A -CF ₂ -CF ₂ -, R _A - CF ₂ -CF (CF ₃ ) -, CF ₃ -C (RA) F- and (CF ₃ ) RA - with R _A having any of the meanings given below for R, it being understood that R _A does not represent either a halogen atom or a perhalogenated organic radical,

R represents SO ₂ Rf or

(i) a halogen atom;

(ii) an alkyl chain optionally interrupted by one or more oxygen or sulfur atom (s) or carbonyl function (s) and optionally substituted by one or more halogen atom (s) or carboxyl or silyl groups,

(iii) an alkenyl chain optionally interrupted by one or more oxygen or sulfur atom (s) or carbonyl function (s) and optionally substituted by one or more halogen atom (s) or carboxyl or silyl group (s) ;

(iv) an aryl group optionally substituted by one or more halogen atom (s) or alkyl or alkenyl group (s);

(v) an arylalkyl group optionally substituted by one or more halogen atom (s); (vi) an arylalkenyl group optionally substituted by one or more halogen atom (s);

(vii) a group -CO-RE WHERE R _E represents a halogen atom or a C1 to C alkyl group;

(viii) a group -0-CR _C RD-RB OÙ R _B represents an alkylperfluorinated radical; and R _c and RD are, independently of each other, a radical chosen from (ii), (iii), (iv), (v) and (vi) above, it being understood that Rc and RD do not carry d halogen atom, provided that when n is equal to 1 and RfS0 ₂ and R both represent a group -SO ₂ CF ₃ then the three groups A do not simultaneously represent either a methyl radical or an isopropyl radical or if the one of the groups A represents a tert-butyl radical, then the other two groups A are different from a methyl radical and their derivatives.

3. Compound according to one of claims 1 or 2 characterized in that this center of chirality is located either at one of the groups A, R or Rf or on the silicon atom.

4. Compound according to one of the preceding claims, characterized in that it has at least one center of chirality at the level of one of the groups A.

5 Compound according to one of the preceding claims, characterized in that it has at least one axis of chirality at the level of one of the groups A.

6. A compound according to claim 5 characterized in that the center of chirality is carried by a carbon placed in the α position of the carbon bonded to the silicon atom.

7. Compound according to one of the preceding claims, characterized in that said compound corresponds to the general formula (I) or (la) in which n and m are respectively equal to 1 and 3.

8. Compound according to one of the preceding claims, characterized in that the said compound has at least one -S0 ₂ Rf radical on its nitrogen atom.

9. Compound according to one of the preceding claims, characterized in that it has two SO ₂ Rf radicals on its nitrogen atom.

10. Compound according to one of the preceding claims, characterized in that at least one of the groups A represents a polycyclic saturated cycloaliphatic radical carrying at least one alkyl chain, preferably Ci to Ce, optionally interrupted by one or more oxygen atoms and / or CO units and optionally substituted by or comprising at the chain end a phenyl group substituted or not.

11. Compound according to one of the preceding claims, characterized in that at least one of the groups A represents at least one cycloalkyl or alkylcycloalkyl, unsaturated, saturated or aromatic radical bearing substituents capable of establishing internal chelations and / or to create steric hindrance.

12. A compound according to claim 11 characterized in that the substituents are chosen from tertiary C1 to Ce alkyl C ₆ to C ₆ alkoxy groups, esters, tertiary amines, ethers, and nitriles.

13. Compound according to claim 1 or 2 characterized in that it is chosen from:

- N- (trimethylsilyl) -bis (pentafluorophenylsulfonyl) imide

- N- (trimethylsilyl) -bis (perfluorobutylsulfonyl) imide - N- (dimethylpentafluorophenylsilyl) -bis (trifluoromethane sulfonyl) imide

- dimethyl di [bis (trifluoromethanesulfonyl) iminojsilane

- 1-methyl-1 - [bis (trifluoromethanesulfonyl) amino] silacyclobutane - (+) - N- [6,6-dimethyl-2-propyibicyclo [3,1, 1] hept-3-yl) - dimethylsilyl] bis (trifluoromethanesulfonyl) imide

(+) N - [(6,6-dimethyl-2-phenethylbicyclo [3,1,1] hept-3-yl) dimethylsilyl] bis (trifluoromethanesulfonyl) imide

(+) N-2- (methoxymethyl) -6,6-dimethylbicyclo [3,1, 1] hept-3-yl) dimethylsilyl] bis (trifluoromethanesulfonyl) imide

(+) - N- [2- (ethoxymethyl) -6,6-dimethylbicycIo [3,1, 1] hept-3- yl) dimethylsiIyl] bis (trifluoromethanesulfonyl) imide

(+) - N- [2-benzyloxymethyl) -6,6-dimethylbicyclo [3,1, 1] hept-3- yl) dimethylsilyl] bis (trifluoromethanesulfonyl) imide - (+) - N- [2- (3, 5-dimethylbenzyloxymethyl) -6,6-dimethylbicyclo

[3,1, 1] hept-3-yl) dimethylsilyl] bis (trifluoromethanesuifonyl) imide (+) - N- [2- (benzoyloxymethyl) -6,6-dimethylbicyclo [3,1, 1] hept- 3-yl) dimethylsilyl] bis (trifluoromethanesulfonyl) imide

- (+) - N- {dimethyl [trans-2- (1 -naphthyl) cyclohexyl] silyl} bis (trifluoromethanesulfonyl) imide and

- (-) - N- {dimethyl [trans-2- (1-naphthyl) cyclohexyl] silyl} bis (trifluoromethanesulfonyl) imide.

14. Process useful for preparing compounds of general formula I according to one of claims 1 to 13 characterized in that at least one compound of general formula (II) is reacted

(A) ₃ sι ^ ₍ , „ ₎

with at least one compound of general formula (IV)

in which, A, R, Rf, y and z are as defined in claim 1 and in that said compound of general formula (I) is recovered.

15. Use of a compound of general formula (I) according to one of claims 1 to 13, as Lewis acid.

16. Use according to claim 15 characterized in that said compound of general formula (I) is used to catalyze Diels-Alder reactions, carbonyl allylations, ene reactions, Prins reactions, and Michael additions.

17. Use according to claim 15 or 16 characterized in that said compound of general formula (I) is generated in situ in said reaction medium.

18. Use according to claim 15, 16 or 17 characterized in that the compound of general formula (I) is used in the presence of a tertiary amine or of a pyridine derivative sufficiently congested to selectively complex the proton with respect to the group ( A ₃ ) Yes.

19. Use according to claim 18 characterized in that the basic compound is 2,6-bis (tbutyl) -4-methylpyridine.

20. Use according to one of claims 15 to 19 characterized in that the compound of general formula (I) is present in an amount of 0.5 to 100 mol% expressed relative to the defective reagent.

21. Use according to one of claims 15 to 20 characterized in that the compound of general formula (I) is (+) N-2- (methoxymethyl) - 6,6-dimethylbicycio [3.1.1] hept-3 -yl) dimethylsilyl] bis (trifluoro-methanesulfonyl) imide.