EP3571188A1 - Method for preparing thiolactones, thiolactones obtained by said method and uses thereof - Google Patents

Abstract

The present invention relates to a method for the preparation of substituted thiolactones of formula (I), substituted thiolactones of formula (I') that can be obtained by implementing said method, the use of substituted thiolactones of formula (I) or (I') for the preparation of polymers or for the functionalisation of particles, flat surfaces or polymers.

Description

 PROCESS FOR THE PREPARATION OF THIOLACTONES,

 THIOLACTONES OBTAINED BY THIS METHOD AND USES

 The present invention relates to the field of thiolactones.

 More particularly, the present invention relates to a process for the preparation of substituted thiolactones of formula (I), substituted thiolactones of formula (Γ) obtainable by the implementation of this method, the use of substituted thiolactones of formula (I) or of formula (Γ) for the preparation of polymers or for the functionalization of particles, flat surfaces or polymers.

 Thiolactones are heterocyclic compounds analogous to lactones, in which an oxygen atom is replaced by a sulfur atom. The sulfur atom is in the ring and is adjacent to a carbonyl group. The heterocycle of the thiolactones may be substituted with at least one chemical group, in particular with an alkyl or aryl group.

 Several methods for synthesizing thiolactones have already been proposed.

Korte et al. [Chem. Ber. , 1961, 94, 1966-1976] have for example proposed either to carry out a thermal cyclization of an alkyl substituted mercaptocarboxylic acid or to directly substitute a thiolactone with an alkyl radical in the presence of an alkyl halide group ( RX) and lithium dialkylamide (LiNR ' ₂ ). These two synthetic routes can be represented by the following reaction scheme (1):

Synthesis

 multistep

 Reagents

 departure

 R = Alkyl

 Reaction scheme (1)

According to the synthesis route by thermal cyclization, only the last cyclization step is general, the preceding steps leading to the mercaptocarboxylic acid and the reagents used being specific to the type. group R that it is desired to introduce on the heterocycle. In addition, these two synthesis routes do not allow the introduction of substituents other than alkyl groups.

A more recent synthetic method provides access to thiolactones having alkyl or aryl groups (Filippi et al., Tet Lett, 2006, 47, 6067-6070). This process is based on a catalytic isomerization process of a thionolactone to a thiolactone in the presence of boron trifluoride (BF ₃ ) and diethyl ether (Et ₂ O) in an organic solvent such as toluene under reflux according to following reaction scheme (2):

 R = alkyl, phenyl

Reaction scheme (2)

 However, this process utilizes a Lewis acid type catalyst (eg, boron trifluoride) and can not be readily used for the synthesis of thiolactones bearing substituents other than alkyl or phenyl moieties, such as complex organic functions and / or or incompatible with this type of catalyst. In addition, isolated yields of thiolactones are often low. Finally, this process requires the synthesis of the starting thionolactones from the corresponding lactones.

 There is therefore a need for a process which makes it possible to synthesize thiolactones substituted by various functional groups in a flexible and simple manner, and in a process that is both efficient and economical.

The subject of the present invention is therefore a process for the preparation of substituted thiolactones of formula (I) below: in which :

R ¹ , R ² , R ³ and R ⁴ , which may be identical or different, represent a hydrogen atom or a group chosen from alkyl, acyl, aryl, heteroaryl, saturated or unsaturated cycloalkyl and saturated or unsaturated heterocycloalkyl groups; radicals R ¹ , R ² , R ³ and R ⁴ may also together form a saturated or unsaturated cycloalkyl or heterocycloalkyl group or an aryl or heteroaryl group; and

- R ⁵ , R ⁶ and R ⁷ , identical or different, are:

(a) selected from hydrogen, cyano (CN), alkyl, acyl, aryl, heteroaryl, aralkyl, saturated or unsaturated cycloalkyl, saturated heterocycloalkyl, or unsaturated, and a phthalimido group, said alkyl, acyl, aryl, heteroaryl, aralkyl, saturated or unsaturated cycloalkyl, saturated or unsaturated heterocycloalkyl and phthalimido groups which may be substituted with a group X selected from the following groups: P (0) (OR ⁸ ) (OR ^{8 '} ) in which the radicals R ⁸ and R ^8' , which may be identical or different, represent a hydrogen atom or an alkyl radical; C _n F ₂ n + i wherein n is an integer from 1 to 20; SiR ⁹ _p (OR ¹⁰ ) 3 _-p in which the radicals R ⁹ and R ¹⁰ , which may be identical or different, represent a hydrogen atom or an alkyl radical and p is an integer equal to 0, 1 or 2; BF ₃ M ⁺ wherein M = K or Na; B (OR ⁿ ) ₂ in which the two radicals R ¹¹ , which may be identical or different, represent a hydrogen atom or an alkyl radical or form a carbon ring with the two oxygen atoms to which they are bonded; OR ¹² wherein R ¹² represents a hydrogen atom or an alkyl, aryl or aralkyl radical; 0 (C = O) R ¹³ wherein R ¹³ represents a hydrogen atom or an alkyl, aryl or aralkyl radical; 0 (C = O) OR ¹⁴ wherein R ¹⁴ represents a hydrogen atom or an alkyl, aryl or aralkyl radical; N ⁺ R ¹⁵ R ¹⁵ R ^{15 "} A ^" in which the radicals R ¹⁵ , R ^{15 '} and R ^{15 "} , which may be identical or different, represent a hydrogen atom or an alkyl, aryl or aralkyl radical and A represents an atom of chlorine or bromine; NR ¹⁶ (C = O) R ^{16 '} in which the radicals R ¹⁶ and R ^16' , which are identical or different, represent a hydrogen atom or an alkyl or aryl radical or are connected together and form a a ring such as a pyrrolidone or caprolactam ring; NR ¹⁷ (C = O) OR ^{17 '} wherein R ¹⁷ and R ^17' , which may be identical or different, represent a hydrogen atom or an alkyl, aryl or aralkyl radical; CN; a halogen atom selected from Cl, F and Br; NCS; OCH ₂ -epoxy; COOR ¹⁸ wherein R ¹⁸ represents a hydrogen atom, an alkyl, aryl or aralkyl radical; CONR ¹⁹ R ^{19 '} wherein R ¹⁹ and R ^{19 ',} identical or different, represent a hydrogen atom or an alkyl or aryl radical; S0 ₂ R ²⁰ wherein R ²⁰ represents an alkyl or aryl radical; azide (N ₃ ) and alkyne; or

(b) as together form a polymer chain P ¹ ; or

(c) such that R ⁵ is different from the other two groups R ⁶ and R ⁷ , R ⁶ and R ⁷ have the same definition as in alternative (a), and R ⁵ is a thiolactone radical of the following formula:

in which R ¹ , R ² , R ³ , and R ⁴ have the same meaning as in formula (I) above, R ⁶ and R ⁷ have the same definition as in alternative (a), Z represents a divalent group chosen from a carbonyl group, a carbonate group, an alkylene group and an arylene group, and the # sign represents the attachment point of the thiolactone radical to the -CR ⁶ R ⁷ CH ₂ -thiolactone radical of the compound of formula (I );

said method being characterized in that it comprises at least the following steps: 1) a step during which, in the presence of a radical initiator, a xanthate of the following formula (II) is reacted:

(H)

 in which :

R ²¹ , R ²² , R ²³ and R ²⁴ , which may be identical or different, represent a hydrogen atom or a group chosen from alkyl, acyl, aryl, heteroaryl, alkene, alkyne, saturated or unsaturated cycloalkyl and saturated heterocycloalkyl groups; or unsaturated ¹ , the radicals R ²¹ , R ²² , R ²³ and R ²⁴ may also together form a saturated or unsaturated cycloalkyl or heterocycloalkyl group or an aryl or heteroaryl group; and

- R ^5a , R ⁶ and R ⁷ , identical or different, are:

(a ') selected from hydrogen, cyano (CN), alkyl, acyl, aryl, heteroaryl, aralkyl, saturated or unsaturated cycloalkyl, saturated heterocycloalkyl or unsaturated and a phthalimido group, said alkyl, acyl, aryl, heteroaryl, aralkyl, saturated or unsaturated cycloalkyl, saturated or unsaturated heterocycloalkyl and phthalimido groups which may be substituted with a group X selected from the following groups: P (0) (OR ⁸ ) (OR ⁸ ) in which the radicals R ⁸ and R ^{8 '} , which may be identical or different, represent a hydrogen atom or an alkyl radical; C _n F ₂ n + i wherein n is an integer from 1 to 20; SiR ⁹ _p (OR ¹⁰ ) 3 _-p in which the radicals R ⁹ and R ¹⁰ , which may be identical or different, represent a hydrogen atom or an alkyl radical and p is an integer equal to 0, 1 or 2; BF ₃ M ⁺ wherein M = K or Na; B (OR ⁿ ) ₂ in which the two radicals R ¹¹ , which may be identical or different, represent a hydrogen atom or an alkyl radical or form a carbon ring with the two oxygen atoms to which they are bonded; OR ¹² wherein R ¹² represents a hydrogen atom or an alkyl, aryl or aralkyl radical; 0 (C = O) R ¹³ wherein R ¹³ represents a hydrogen atom or an alkyl, aryl or aralkyl radical; 0 (C = O) OR ¹⁴ wherein R ¹⁴ represents a hydrogen atom or an alkyl, aryl or aralkyl radical; N ⁺ R ¹⁵ R ¹⁵ R ^{15 "} A ^" in which the radicals R ¹⁵ , R ^{15 '} and R ^{15 "} , which may be identical or different, represent a hydrogen atom or an alkyl, aryl or aralkyl radical and A represents an atom of chlorine or bromine; NR ¹⁶ (C = O) R ^{16 '} in which the radicals R ¹⁶ and R ^16' , which are identical or different, represent a hydrogen atom or an alkyl or aryl radical or are connected together and form a a ring such as a pyrrolidone or caprolactam ring; NR ¹⁷ (C = O) OR ^{17 '} wherein R ¹⁷ and R ^17' , which may be identical or different, represent a hydrogen atom or an alkyl, aryl or aralkyl radical; CN; a halogen atom selected from Cl, F and Br; NCS; OCH ₂ -epoxy; COOR ¹⁸ wherein R ¹⁸ represents a hydrogen atom, an alkyl, aryl or aralkyl radical; CONR ¹⁹ R ^{19 '} wherein R ¹⁹ and R ^{19 ',} identical or different, represent a hydrogen atom or an alkyl or aryl radical; S0 ₂ R ²⁰ wherein R ²⁰ represents an alkyl or aryl radical; azide (N ₃ ) and alkyne; or

(b ') as together form a polymer chain P ¹ ; or (c ') such that R ^5a is different from the other two groups R ⁶ and R ⁷ , R ⁶ and R ⁷ have the same definition as in the alternative (a') and R ^5a is a xanthate radical of formula:

in which R ²¹ , R ²² , R ²³ and R ²⁴ have the same meaning as in formula (II) above, R ⁶ and R ⁷ have the same definition as in the alternative (a '), Z represents a divalent group selected from a carbonyl group, a carbonate group, an alkylene group and an arylene group, and the sign # represents the point of attachment of the xanthate group to the -CR ⁶ R ⁷ -xanthate group of the compound of formula (II);

with a monomer comprising at least one ethylenic unsaturation of formula (III) below:

 (III) wherein:

R ²⁵ represents a group selected from saturated or unsaturated alkyl, acyl, aryl, heteroaryl, aralkyl, cycloalkyl and saturated or unsaturated heterocycloalkyl groups;

Y is an oxygen atom or an NR ²⁶ radical in which R ²⁶ represents a hydrogen atom or an alkyl group, and preferably an oxygen atom; and

- R ¹ , R ² , R ³ and R ⁴ have the same meaning as in formula (I) above;

 to form a mono-adduct of formula (IV) below:

 (IV) wherein:

- R ¹ , R ² , R ³ and R ⁴ have the same meaning as in formula (I) above;

- R ²¹ , R ²² , R ²³ and R ²⁴ have the same meaning as in formula (II) above; and R ²⁵ has the same meaning as in formula (III) above; and

- R ^5b , R ⁶ and R ⁷ , identical or different, are:

(a ") selected from hydrogen, cyano (CN), alkyl, acyl, aryl, heteroaryl, aralkyl, saturated or unsaturated cycloalkyl, saturated heterocycloalkyl or unsaturated and a phthalimido group, said alkyl, acyl, aryl, heteroaryl, aralkyl, saturated or unsaturated cycloalkyl, saturated or unsaturated heterocycloalkyl and phthalimido groups which may be substituted with a group X selected from the following groups: P (0) (OR ⁸ ) (OR ⁸ ) in which the radicals R ⁸ and R ^{8 '} , which may be identical or different, represent a hydrogen atom or an alkyl radical; C _n F ₂ n + 1 in which n is an integer ranging from 1 to 20 ; SiR ⁹ _p (oR ¹⁰⁾ 3 _-p wherein the radicals R ⁹ and R ^10, identical or different, represent a hydrogen atom or an alkyl radical and p is an integer 0, 1 or 2; BF ₃ M ⁺ in which M = K or Na; B (OR ⁿ ) ₂ in which the two radicals R ¹¹ , id entic or different, represent a hydrogen atom, an alkyl radical or form a carbon ring with the two oxygen atoms to which they are attached; OR ¹² wherein R ¹² represents a hydrogen atom or an alkyl, aryl or aralkyl radical; 0 (C = O) R ¹³ wherein R ¹³ represents a hydrogen atom or an alkyl, aryl or aralkyl radical; 0 (C = O) OR ¹⁴ wherein R ¹⁴ represents a hydrogen atom or an alkyl, aryl or aralkyl radical; N ⁺ R ¹⁵ R ¹⁵ R ^{15 "} A ^" in which the radicals R ¹⁵ , R ^{15 '} and R ^{15 "} , which may be identical or different, represent a hydrogen atom or an alkyl, aryl or aralkyl radical and A represents an atom of chlorine or bromine; NR ¹⁶ (C = O) R ^{16 '} in which the radicals R ¹⁶ and R ^16' , which are identical or different, represent a hydrogen atom or an alkyl or aryl radical or are connected together and form a a ring such as a pyrrolidone or caprolactam ring; NR ¹⁷ (C = O) OR ^{17 '} wherein R ¹⁷ and R ^17' , which may be identical or different, represent a hydrogen atom or an alkyl, aryl or aralkyl radical; CN; a halogen atom selected from Cl, F and Br; NCS; OCH ₂ -epoxy; COOR ¹⁸ wherein R ¹⁸ represents a hydrogen atom, an alkyl, aryl or aralkyl radical; CONR ¹⁹ R ^{19 '} wherein R ¹⁹ and R ^{19 '} , which may be identical or different, represent a hydrogen atom or an alkyl or aryl radical; ; S0 ₂ R ² ° wherein R ²⁰ represents an alkyl or aryl radical; azide (N ₃ ) and alkyne; or

(b ") as together form a polymer chain P ¹ , or

(c ") such that R ^5b is different from the other two groups R ⁶ and R ⁷ , R ⁶ and R ⁷ have the same definition as in alternative (a") and R ^5b is a mono-adduct radical of following formula :

in which R ¹ , R ² , R ³ , R ⁴ , R ²¹ , R ²² , R ²³ , R ²⁴ , Y and R ²⁵ have the same meaning as in formula (IV) above, R ⁶ and R ⁷ have the same definition as in alternative (a "), Z represents a divalent group selected from a carbonyl group, a carbonate group, an alkylene group and an arylene group, and the sign # represents the anchor point of the mono radical -adducted with the radical - CR ⁶ R ⁷ -monoadduct of the compound of formula (IV);

 2) a step of thermolysis of the mono-adduct of formula (IV) obtained above in the preceding step to form a substituted thiolactone of formula (I) corresponding.

The process for preparing the substituted thiolactones of formula (I) according to the invention can be represented by the following reaction scheme (3):

 Reaction scheme (3)

Thanks to the process according to the present invention and as described above, it is now possible to access in a simple, fast and with a good yield to thiolactones substituted by various organic groups.

In particular, the process of the invention makes it possible, during step 2) of thermolysis, to access, in a single simple step, a substituted thiolactone. Thermolysis 2) implements less aggressive conditions than the conditions generally used in the prior art such as acid-base conditions that employ acidic and / or basic reagents in several steps. These acid-base conditions are not desirable because they do not make it possible to obtain substituted thiolactones having fragile chemical groups such as cyano groups; moreover, they very often lead to poor yields by the formation of by-products.

In the process of the invention, simple heating promotes cyclization and thus obtaining a substituted thiolactone with acceptable yields. The alkyl radicals mentioned for R ¹ , R ² , R ³ , R ⁴ , n 5 n 5a n 5b n6 p 7 p 8 p8 'p 9 p lO PLLP l2 p l3 p l4 p l5 ρ 15 p l5 "p l6 p l6' v _/ v _f Γ \, Γ, Γ, Γ, Γ , Γ, Γ, r \ _f Γ \, Γ, \, Γ, rv _/ rv _/

R ¹⁷ , R ¹⁷ , R ¹⁸ , R ¹⁹ , R ^{19 '} , R ²⁰ , R ²¹ , R ²² , R ²³ , R ²⁴ and R ²⁵ may be linear or branched, substituted or unsubstituted, and may contain from 1 to 12 carbon atoms, and preferably 1 to 6 carbon atoms. They are preferably chosen from methyl, ethyl, n-propyl, naphthyl, n-butyl, n-butyl, n-butyl, n-butyl, n-butyl, n-pentyl, neo-pentyl, tert-pentyl, hexyl, r? -octyl, / ^'n-octyl, 2-ethyl-l-hexyl, 2,2,4-trimethylpentyl, nonyl, decyl, dodecyl and benzyl. Among such groups, most preferred any of methyl, ethyl, r? -Propyl, / ^'so-propyl or n-butyl.

The alkyl radicals mentioned for R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ^5a , R ^5b , R ⁶ , R ⁷ ,

R ²⁰ , R ²¹ , R ²² , R ²³ , R ²⁴ and R ²⁵ may be fluorinated or perfluorinated.

For the purposes of the present invention, an acyl group denotes a group of formula -C (= O) -D, in which D denotes a hydrogen atom or a linear or branched, saturated or unsaturated hydrocarbon-based chain which may contain from 1 to 12 carbon atoms, and preferably 1 to 6 carbon atoms. Among such acyl groups mentioned for R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ^5a , R ^5b , R ⁶ , R ⁷ , R ²¹ , R ²² , R ²³ , R ²⁴ and R ²⁵ , mention may especially be made of formyl, acetyl, propanoyl or pivaloyl groups.

For the purposes of the present invention, the term "aryl group" means an optionally mono- or polysubstituted monocyclic or polycyclic aromatic hydrocarbon group comprising from 3 to 10 carbon atoms, and preferably from 3 to 6 carbon atoms. As the aryl radical mentioned for R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ^5a , R ^5b , R ⁶ , R ⁷ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ^{15 '} , R ^{15 "} , R ¹⁶ , R ^{16 '} , R ¹⁷ , R ^17' , R ¹⁸ , R ¹⁹ , R ^{19 '} , R ²⁰ , R ²¹ , R ²² , R ²³ , R ²⁴ and R ²⁵ , may in particular mention may be made of naphthyl, anthranyl, phenanthryl, o-tolyl, p-tolyl, xylyl, ethylphenyl, mesityl and phenyl groups Amongst such groups, the phenyl group is particularly preferred, within the meaning of the present invention the cycloalkyl group is a group cyclic having from 3 to 10 carbon atoms, and preferably from 3 to 7 carbon atoms. The cycloalkyl group is preferably saturated. Among such cycloalkyl groups mentioned for R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ^5a , R ^5b , R ⁶ , R ⁷ , R ²¹ , R ²² , R ²³ , R ²⁴ and R ²⁵ , mention may in particular be made of cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl or cycloheptyl groups.

The cycloalkyl groups mentioned for R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ^5a , R ^5b , R ⁶ , R ⁷ , R ²¹ , R ²² , R ²³ , R ²⁴ and R ²⁵ may be fluorinated or perfluorinated.

Still within the meaning of the present invention, a heterocycloalkyl group is a cyclic group comprising from 3 to 10 carbon atoms, and preferably from 3 to 6 carbon atoms, and at least one heteroatom chosen from N, O, P, Si and S. The heterocycloalkyl group is preferably saturated. Among such heterocycloalkyl groups mentioned for R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ^5a , R ^5b , R ⁶ , R ⁷ , R ²¹ , R ²² , R ²³ , R ²⁴ and R ²⁵ , mention may in particular be made of oxacyclopropanyl, azacyclopropanyl, thiacyclopropanyl, tetrahydrofuranyl, pyrrolidinyl, tetrahydrothiophenyl, tetrahydropyranyl, piperidinyl, piperazinyl or thiacyclohexane groups.

The heterocycloalkyl groups mentioned for R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ^5a , R ^5b , R ⁶ , R ⁷ , R ²¹ , R ²² 'R ²³ , R ²⁴ and R ²⁵ may be fluorinated or perfluorinated.

For the purposes of the present invention, a heteroaryl group is a monocyclic or polycyclic aromatic group, optionally mono or polysubstituted, comprising from 3 to 10 carbon atoms, and preferably from 5 to 6 carbon atoms, and at least one chosen heteroatom. among N, O, P, Si and S. Among such heteroaryl groups mentioned for R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ^5a , R ^5b , R ⁶ , R ⁷ , R ²¹ , R ²² R ²³ , R ²⁴ and R ²⁵ may be mentioned in particular furanyl, thiophenyl, pyrrolyl, pyridinyl, pyranyl, oxazinyl, thazinyl, pyrimidinyl, piperazinyl or thiinyl groups.

An aralkyl group, within the meaning of the present invention, is a group comprising at least one alkyl radical and at least one aryl radical, said alkyl and aryl radicals being linked by a carbon-carbon bond, and said alkyl and aryl radicals having the same definition than that given for the alkyl and aryl radicals above. As aralkyl group, mention may in particular be made of the benzyl group.

 An alkylene group, within the meaning of the present invention, can be linear or branched, substituted or unsubstituted, and can comprise from 1 to 12 carbon atoms, and preferably from 1 to 6 carbon atoms.

 An arylene group within the meaning of the present invention may be mono or polysubstituted, and may comprise from 10 to 30 carbon atoms, and preferably from 10 to 20 carbon atoms.

According to alternative (b) for the formula (I), the radicals R ⁵ , R ⁶ and R ⁷ are chosen such that the group -CR ⁵ R ⁶ R ⁷ forms a polymer chain P ¹ ; according to alternative (b ') for formula (II), the radicals R ^5a , R ⁶ and R ⁷ are chosen such that the group -CR ^5a R ⁶ R ⁷ forms a polymer chain P ¹ ; and according to alternative (b ") for formula (IV), the radicals R ^5b , R ⁶ and R ⁷ are chosen such that the group -CR ^5b R ⁶ R ⁷ forms a polymer chain P ¹ .

According to the present invention, the term polymer chain P ¹ for the groups -CR ⁵ R ⁶ R ⁷ , -CR ^5a R ⁶ R ⁷ , and -CR ^5b R ⁶ R ⁷ , any sequence of monomer units obtained by a reversible addition-fragmentation controlled radical polymerization process (also known as RAFT / MADIX) such as the RAFT / MADIX method described for example by Moad et al. [Aust. J. Chem. , 2012, 65 (8), 985-1076] or by Destarac et al. [ACS Symposium Series, Vol. 854, American Chemical Society, 2003. Matyjaszewski, K., Ed. Advances in Controlled / Living Radical Polymerization, p. 536] or by atom transfer such as the ATRP process of the English-speaking Atom Transfer Radical Polymerization described by example by Matyjaszewski et al. [Chem. Rev., 2001, 101 (9), 2921-2990] implemented such that the terminal monomeric unit connected respectively to the sulfur atom of thiocarbonylthio group (RAFT / MADIX) or halogen (Cl, Br) for the ATRP is of the acrylate type, for example methyl acrylate, or acrylamido, such as N-isopropylacrylamide. The polymer chain P ¹ may also result from the transformation of a polymer having at least one -OH or at least one -NH ₂ terminal into a suitable xanthate end.

The polymer chain P ¹ may be chosen from a polydimethylsiloxane, a random or block copolymer based on dimethylsiloxane units, an ethylene polyoxide, a propylene polyoxide, a block copolymer or random block copolymer. ethylene and propylene oxide, a poly (butylene oxide), a random or block copolymer based on ethylene oxide and butylene oxide, a polyethylene tetramethylene oxide (poly (tetrahydrofuran)), a polylactide polycaprolactone, polyester, polyethylene, poly (ethylene-co-butylene) (or hydrogenated polybutadiene), polypropylene, oligopeptide, polypeptide, polyamide, polyurethane, polystyrene and polymer synthesized by controlled radical polymerization unsaturated monomers according to techniques known in the state of the art such as ATRP, NMP (well known under the name of "nitroxide mediated polymerization") described for example by Hawker et al. l. [Chem. Rev. , 2001, 101, 3661-3688], RAFT / MADIX, OHMRP (well known under the term "organoheteroatom mediated living radical polymerization") described for example by Yamago et al. [Chem. Rev. , 2009, 109, 5051-5068] etc ....

Preferably, at least one of R ²¹ or R ²² is different from a hydrogen atom.

In a particular embodiment, R ²¹ , R ²² , R ²³ and R ²⁴ represent a hydrogen atom or an alkyl group.

R ²¹ (respectively R ²² ) may be an alkyl group, especially a methyl group, and R ²² (respectively R ²¹ ) may be a hydrogen atom.

Preferably, at least one of R ²³ and R ²⁴ is different from a hydrogen atom.

More preferably, R ²³ (respectively R ²⁴ ) is an alkyl group, especially a methyl group, and R ²⁴ (respectively R ²³ ) is a hydrogen atom or an alkyl group, especially a methyl group. Preferably, the group R ⁵ is different from a hydrogen atom.

According to a particularly preferred embodiment of the invention, R ⁵ is a cyano group or a phthalimido group.

In a preferred embodiment, at least one of the groups R ⁶ or R ⁷ is a hydrogen atom and advantageously, the two groups R ⁶ and R ⁷ are hydrogen atoms.

In a particular embodiment, R ²⁵ is an alkyl group, particularly a methyl group.

In a particular embodiment, R ¹ , R ² , R ³ and R ⁴ represent a hydrogen atom or an alkyl group.

Preferably, R ¹ (respectively R ² ) is an alkyl group, especially a methyl group, and R ² (respectively R ¹ ) is a hydrogen atom.

Preferably, at least one of the groups R ³ or R ⁴ is a hydrogen atom and more preferably the two groups R ³ and R ⁴ are hydrogen atoms.

The group R ²⁶ is preferably a methyl group.

 In formula (I) as defined above, alternatives (a) and (b) are preferred, and alternative (a) is even more preferred.

 In the formula (II) as defined above, the alternatives (a ') and

(b ') are preferred, and the alternative (a') is even more preferred.

 In the formula (IV) as defined above, the alternatives (a ") and (b") are preferred, and the alternative (a ") is even more preferred.

 According to a particularly advantageous embodiment, the process of the invention leads to the formation of a thiolactone of formula (I) chosen from:

3- (4-methyl-5-oxotetrahydrothiophen-2-yl) propanenitrile (TL1), and 2- (2- (4-methyl-5-oxotetrahydrothiophen-2-yl) ethyl) isoindolin-1,3 (TL2).

When not commercial, xanthates of formula (II):

(H)

can be obtained according to a process similar to that used in the international application WO 2004/024681. In particular, they can be obtained according to a process comprising the following steps: a) reacting, in an organic solvent, an alcohol of formula (VI) below:

 (VI)

in which the radicals R, R, R and R have the same meaning as in the xanthates of formula (II) above, with carbon disulfide (CS ₂ ) in the presence of a base to obtain a salt of formula ( VII)

 (VU)

in which the radicals R ²¹ , R ²² , R ²³ and R ²⁴ have the same meaning as the xanthates of formula (II) above and J ⁺ is a cation chosen from alkali metal cations such as a K ⁺ cation or Na ⁺ , then b) reacting the compound of formula (VII) obtained in step a) above with a compound of formula (VIII) below:

in which R ^5a , R ⁶ and R ⁷ have the same meaning as in the xanthate of formula (II) above, to obtain a corresponding xanthate of formula (II). The first step a) of preparing a salt of formula (VII) is preferably carried out at room temperature, in particular in an organic solvent such as tetrahydrofuran and in particular using a strong base, preferably potassium hydroxide. The duration of step a) is generally about 20 to 24 hours.

 The second step b) of preparing a xanthate of formula (II) is preferably carried out in an organic solvent such as acetone and in particular in an ice bath, the addition reaction of the compound of formula (VIII) being highly exothermic. Once the addition of the compound of formula (VIII) is complete, the reaction is preferably carried out at room temperature, in particular for a period of about 2 to 4 hours. When the reaction is complete, the xanthate of formula (II) thus obtained can be filtered, and then the filtrate is preferably concentrated in vacuo. The xanthate of formula (II) can then be engaged in the process according to the present invention without further purification.

When the group -CR ^5a R ⁶ R ⁷ is a polymer chain P ¹ , the xanthate of formula (II) can be obtained by RAFT / MADIX polymerization of monomers or by organic synthesis of a polymer-xanthate according to the reaction scheme ( 4) next:

OH-polymer, or

polymer-NH ₂

(II-b)

 Reaction scheme (4)

 According to one embodiment of the invention, the xanthate of formula (II) is S- (cyanomethyl) -O- (3-methylbutan-2-yl) carbonodithioate (XAl) and S - ((1-3) dioxoisoindolin-2-yl) methyl) -O- (3-methylbutan-2-yl) carbonodithioate (XA2).

Step 1) of preparation of the mono-adduct of formula (IV) of the process according to the invention can be carried out without solvent, in water or in an organic solvent. It is preferably carried out in an organic solvent or in water, and even more preferably in an organic solvent. The organic solvent which can be used during this stage 1) is then preferably chosen from toluene, tetrahydrofuran (THF), ethyl acetate and 1,4-dioxane. Among such organic solvents, toluene is particularly preferred.

 For the purposes of the present invention, the term radical initiator, a chemical species capable of forming free radicals that is to say a chemical species having one or more unpaired electrons on its outer layer.

 According to the process according to the invention, the radical initiator used in step 1) is preferably chosen from organic peroxides, azo derivatives and redox systems.

Among the organic peroxides, mention may in particular be made of dilauroyl peroxide (LPO), t-butyl peroxyacetate, t-butyl peroxybenzoate, t-butyl peroxyoctoate, t-butyl peroxydodecanoate, t-butyl peroxyisobutyrate, t-amyl peroxypyvalate, t-butyl peroxypyvalate, di-isopropyl peroxydicarbonate, dicyclohexyl peroxydicarbonate, dicumyl peroxide, dibenzoyl peroxide, potassium peroxydisulfate, peroxydisulphate. sodium and ammonium peroxydisulfate. Among these organic peroxides, LPO is particularly preferred.

 Among the azo derivatives, mention may in particular be made of 2,2'-azobis (isobutyronitrile), 2,2'-azobis (2-cyano-2-butane), dimethyl-2,2'-azobisdimethylisobutyrate, 4 , 4'-azobis- (4-cyanopentanoic acid), 1,1-azobis- (cyclohexanecarbonitrile), 2- (t-butylazo) -2-cyanopropane, 2,2'-azobis- [2-methyl] N - (1, 1) -bis (hydroxymethyl) -2-hydroxyethyl] propanamide, 2,2'-azobis [2-methyl-N-hydroxyethyl] propanamide, 2,2'-azobis- dihydrochloride ( N, N'-dimethyleneisobutyramidine), 2,2'-azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis- (N, N'-dimethyl isobutyramine), 2,2'-azobis (2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] propionamide) 2,2'-azobis- (2-methyl-N- [1,1-bis (hydroxymethyl) propionamide] 2,2'-azobis- [2-methyl-N- (2-hydroxyethyl) propionamide], 2,2'-azobis (isobutyramide) dihydrate, 2,2'-azobis- (2,2, 4-trimethylpentane) and 2,2'-azobis (2-methylpropane).

 The redox systems are for example chosen from systems comprising combinations such as the following combinations:

 mixtures of hydrogen peroxide, a dialkyl peroxide, a hydroperoxide, a perester, a percarbonate or similar compounds, with an iron salt, a titanium salt, a formaldehyde salt or a sulphoxylate zinc or a salt of sodium formaldehyde sulfoxylate,

 mixtures of hydrogen peroxide, a dialkyl peroxide, a hydroperoxide, a perester, a percarbonate or similar compounds with an organic acid such as ascorbic acid or erythorbic acid,

mixtures of an alkali metal or ammonium persulfate, perborate or perchlorate with an alkali metal bisulfite, such as sodium metabisulphite, mixtures of an alkali metal or ammonium persulfate, perborate or perchlorate with an organic acid such as ascorbic acid or erythorbic acid, or

 mixtures of an alkali metal persulfate with an arylphosphinic acid, such as benzene phosphonic acid or similar compounds.

 Among such redox systems, the combination of ammonium persulfate and sodium formaldehyde sulfoxylate is particularly preferred.

 Moreover, during step 1), the radical initiator can be added to the reaction medium in one or more times, that is to say in portions.

 According to a preferred embodiment of the process of the invention, the radical initiator is added to the reaction medium in portions.

 According to one embodiment of the invention, the mono-adduct of formula (IV) as obtained at the end of step 1) is chosen from methyl-cyano-2-methyl-4 - (( ((3-Methylbutan-2-yl) oxy) carbonothioyl) thio) hexanoate (XA1CN) and methyl 6- (1,3-dioxoisoindolin-2-yl) -2-methyl-4 - ((((3-methylbutan) -2-yl) oxy) carbonothioylthio) hexanoate (XA2PH).

 The monomers of formula (III) are preferably chosen from compounds which are monomers with little or no polymerization under the conditions of temperature and pressure used during step 1) of the process according to the invention, that is to say that is to say that lead to a mono-adduct of formula (IV) without significant presence of diadduit, triadduit, etc. Among such monomers of formula (III), there may be mentioned in particular methyl methyl-4-pentenoate ( al).

The monomers of formulas (III) are generally commercially available. When they are not commercially available, they can be easily obtained by synthetic routes well known to those skilled in the art. Step 1) of the process according to the invention is generally carried out at a temperature ranging from 10 to 140 ° C, and preferably from 40 to 110 ° C, and more preferably between 65 and 90 ° C.

 The duration of said step 1) generally varies from about 3 to 48 hours, and still more preferably from 4 to about 24 hours.

 According to a particular and preferred embodiment of the invention, the mono-adduct of formula (IV) obtained at the end of step 1) is purified, for example by chromatography on silica gel, before being engaged. in the second stage of thermolysis.

 Step 2) of thermolysis of the process according to the present invention can be carried out with or without a solvent. According to a preferred embodiment of the invention, step 2) of thermolysis is carried out without solvent. The temperature of the thermolysis step 2) is generally between about 40 and 210 ° C., preferably between about 100 and 200 ° C. and more particularly between about 160 and 190 ° C.

The thermolysis step 2) is generally carried out at a temperature sufficient to decompose the mono-adduct of formula (IV).

 In the present invention, the term "thermolysis" means thermal decomposition. It is a reaction of chemical decomposition caused by heat. In this case, the action of heat leads to the decomposition of the mono-adduct of formula (IV), allowing the formation of the thiolactone of formula (I).

 In other words, step 2) of the process of the invention does not use base (s) and / or acid (s), and preferably does not implement other reagents than the mono-adduct of formula (IV) from step 1). In other words, only the action of heat leads to the thiolactones of formula (I).

Surprisingly, the mono-adduct of formula (IV) obtained in step 1) has a suitable chemical structure, in particular by defining the groups R ¹ , R ² , R ³ , R ⁴ , R ^5b , R ^6. , R ⁷ , R ²¹ , R ²² , R ²³ , R ²⁴ and R ²⁵ , to allow forming a substituted thiolactone of formula (I) by thermolysis. In other words, cyclization to thiolactone (I) is favored.

 When step 2) of thermolysis is carried out in a solvent, then said solvent is preferably chosen from high-boiling solvents (that is to say having a boiling point greater than or equal to the temperature thermolysis), such as, for example, 1,2-dichlorobenzene.

 Furthermore, the thermolysis step 2) can be carried out at atmospheric pressure or under vacuum, especially in the latter case, to eliminate any volatile by-products that may be formed during the reaction.

 According to a particular embodiment, step 2) of thermolysis is carried out in a closed container (e.g., schlenk tube), and preferably under vacuum.

 According to a particular and preferred form of the invention, step 2) of thermolysis is carried out without solvent and under vacuum.

 At the end of the thermolysis step 2), the thiolactone of formula (I) is preferably purified, for example by chromatography on a silica column.

 Some of the substituted thiolactones of formula (I) directly obtained by implementing the preparation method according to the first subject of the invention are new in themselves and therefore constitute the second subject of the invention.

 The subject of the present invention is therefore also substituted thiolactones of the following formula (Γ):

in which : - R ^{1 '} , R ^2' , R ^{3 '} and R ^4' , which may be identical or different, represent a hydrogen atom or a group chosen from alkyl, acyl, aryl, heteroaryl, saturated or unsaturated cycloalkyl and saturated heterocycloalkyl groups; or unsaturated, the radicals R ^{1 '} , R ^2' , R ^{3 '} and R ^4' may also together form a saturated or unsaturated cycloalkyl or heterocycloalkyl group or an aryl or heteroaryl group; and

- R ^{5 '} , R ^6' and R ^{7 '} are defined according to one of two options (i) or (ii):

(I)

R ^{5 '} is selected from cyano group and phthalimido group; and

R ^{6 '} and R ^7' , which are identical or different, are chosen from a hydrogen atom, an alkyl group, an acyl group, an aryl group, a heteroaryl group, an aralkyl group, a saturated or unsaturated cycloalkyl group and a saturated or unsaturated heterocycloalkyl group, said alkyl, acyl, aryl, heteroaryl, aralkyl, saturated or unsaturated cycloalkyl and saturated or unsaturated heterocycloalkyl groups which may be substituted with a group X selected from the following groups: P (0) (OR ⁸ ) (OR ^{8 '} ) in which the radicals R ⁸ and R ^8' , which may be identical or different, represent a hydrogen atom or an alkyl radical; C _n F ₂ n + i wherein n is an integer from 1 to 20; SiR ⁹ p (OR ¹⁰ ) 3 _-p in which the radicals R ⁹ and R ¹⁰ , which may be identical or different, represent a hydrogen atom or an alkyl radical and p is an integer equal to 0, 1 or 2; BF ₃ M ⁺ wherein M = K or Na; B (OR ⁿ ) ₂ in which the two radicals R ¹¹ , which may be identical or different, represent a hydrogen atom or an alkyl radical or form a carbon ring with the two oxygen atoms to which they are bonded; OR ¹² wherein R ¹² represents a hydrogen atom or an alkyl, aryl or aralkyl radical; 0 (C = O) R ¹³ wherein R ¹³ represents a hydrogen atom or an alkyl, aryl or aralkyl radical; 0 (C = O) OR ¹⁴ wherein R ¹⁴ represents a hydrogen atom or an alkyl, aryl or aralkyl radical; N ⁺ R ¹⁵ R ¹⁵ R ^{15 "} A ^" in which the radicals R ¹⁵ , R ^{15 '} and R ^{15 "} , which may be identical or different, represent a hydrogen atom or an alkyl, aryl or aralkyl radical and A represents an atom of chlorine or bromine; NR ¹⁶ (C = O) R ^{16 '} in which the radicals R ¹⁶ and R ^16' , which may be identical or different, represent a hydrogen atom or an alkyl or aryl radical or are connected together and form a ring such that a pyrrolidone ring or caprolactam; NR ¹⁷ (C = O) OR ^{17 '} wherein R ¹⁷ and R ^17' , which may be identical or different, represent a hydrogen atom or an alkyl, aryl or aralkyl radical; CN; a halogen atom selected from Cl, F and Br; NCS; OCH ₂ -epoxy; COOR ¹⁸ wherein R ¹⁸ represents a hydrogen atom, an alkyl, aryl or aralkyl radical; CONR ¹⁹ R ^{19 '} wherein R ¹⁹ and R ^19' , which may be identical or different, represent a hydrogen atom or an alkyl or aryl radical; S0 ₂ R ²⁰ wherein R ²⁰ represents an alkyl or aryl radical; azide (N ₃ ) and alkyne; or

(ii) R ^{5 '} , R ^6' and R ^{7 '} are such that together they form a polymer chain P ¹ .

 Option (i) is preferred.

In a particular embodiment, R ^{1 '} , R ^2' , R ^{3 '} and R ^4' represent a hydrogen atom or an alkyl group.

Preferably, R ^{1 '} (respectively R ^2' ) is an alkyl group, especially a methyl group, and R ^{2 '} (respectively R ^1' ) is a hydrogen atom.

Preferably, at least one of the groups R ^{3 '} or R ^4' is a hydrogen atom and more preferably both the groups R ^{3 '} and R ^4' are hydrogen atoms.

Preferably, at least one of the groups R ^{6 '} or R ^7' is a hydrogen atom, and more preferably the two groups R ^{6 '} and R ^7' are hydrogen atoms.

 Among the substituted thiolactones of formula (Γ) above, mention may be made in particular of:

 3- (4-methyl-5-oxotetrahydrothiophen-2-yl) propanenitrile (TL1), and

2- (2- (4-methyl-5-oxotetrahydrothiophen-2-yl) ethyl) isoindoline-1,3-dione (TL2). The substituted thiolactones of formula (I) obtainable by carrying out the process according to the present invention, and in particular the thiolactones of formula (Γ) according to the second subject of the present invention may advantageously be used to the synthesis of polymers or for the functionalization of particles, flat surfaces of the metal, glass, ceramic or polymer type.

 Thus, the third subject of the present invention is also the use of at least one substituted thiolactone of formula (Γ), for the synthesis of polymers or for the functionalization of particles, of flat surfaces of metal, glass or ceramic type, or of polymers.

 As regards the preparation of polymers, the thiolactones of formula (I), and in particular of formula (Γ) may be engaged in a polymerization reaction comprising at least one reaction step of a thiolactone of formula (I), in particular of formula (Γ) with a nucleophilic compound which makes it possible to open the thiolactone ring and to obtain a thiol which can then be engaged in an addition or condensation polymerization process with, for example, a diacrylate-type monomer such as described in the reference by Yu et al. [Polym. Chem. , 2015, 6, 1527-1532].

 With regard to the functionalization of surface or polymers, it is thus possible:

according to a first embodiment, grafting substituted thiolactones of formula (I) (respectively of formula (Γ)) on a solid surface or on a polymer in the liquid state, said surface or said polymer comprising chemical functions capable of reacting with one of the groups R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ or R ⁷ (respectively R ^{1 '} , R ^2' , R ^{3 '} , R ^4' , R ⁵ , R ⁶ or R ^{7 '} ) thiolactones of formula (I) (respectively (Γ)), in order to form a covalent bond, or strong interactions of the hydrogen bonding type. By way of example, it is thus possible to graft a thiolactone comprising a phosphonate group as an X substituent of R ⁶ or R ⁷ on a metal surface. According to this first embodiment, after functionalization, the integrity of the thiolactone ring is preserved. according to a second embodiment, grafting the thiolactone substituted by opening the thiolactone ring on a solid surface or on a polymer in the liquid state and reacted with any substance reactive with thiols such as acrylates or alkyl halides for example.

Depending on the nature of the groups R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ or R ⁷ (respectively R ^{1 '} , R ^2' , R ^{3 '} , R ^4' , R ^{5 '} , R ^{6 '} or R ^7' ), it then becomes possible to confer on a material or a polymer the properties corresponding to the type of group R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ or R ⁷ (respectively R ^{1 '} , R ^2' , R ^{3 '} , R ^4' , R ⁵ , R ^{6 '} or R ^7' ) grafted, for example, nonadhering properties when the groups R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ or R ⁷ (respectively R ^{1 '} , R ^2' , R ^{3 '} , R ^4' , R ⁵ , R ^{6 '} or R ^7' ) are perfluorinated groups. It is also possible to introduce an additional function when reacting the thiol obtained by opening the thiolactone with a functional compound reactive with thiols.

 The present invention is illustrated by the following exemplary embodiments, to which it is however not limited.

 EXAMPLES

Example 1 Synthesis of 3- (4-methyl-5-oxotetrahydrothiophen-2-propenenitrile (TLD according to the process according to the invention In this example, the thiolactone of the following formula (TL1) was prepared:

 TL1

Step 1: Preparation of S- (cyanomethyl) -CH3-methylbutan-2-yl carbonodithioate (Xanthate of formula (II);

XA1 1 _._ 1J S-_e__ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

 XAO

500 g (1.13 moles) of 3-methylbutan-2-ol (Alfa Aesar), 63.65 g of potassium hydroxide (KOH, Sigma-3) were suspended in 500 ml of tetrahydrofuran (THF, Sigma-Aldrich). AIdrich) and 90.7 g (1.19 mol) of carbon disulfide (CS ₂ , Sigma-Aldrich) at room temperature for 24 hours.

 After complete dissolution of KOH, the yellow emulsion was concentrated under reduced pressure, then triturated with pentane (Sigma-Aldrich) and finally filtered to obtain 185 g of the expected product XAO in the form of a yellow solid (185 g, 80% yield).

1 H NMR (300.13 MHz, D ₂ O, 298 K) δ: 5.31 (bp, ³ J _{H / H} = 6.4 Hz, 1H, (CH ₃ ) ₂ CHCH (O) CH ₃ ); 2.07-1.84 (m, 1H, (CH ₃ ) ₂ CHCH (O) CH ₃ ); 1.27 (d, ³ J _{H / H} = 6.4 Hz, 3H, (CH ₃ ) ₂ CHCH (O) CH ₃ ); 0.96 (d, ³ _H , _H = 6.9 Hz, 6H, (CH ₃ ) ₂ CHCH (O) CH ₃ ) ppm.

1H NMR (75.47 MHz, D ₂ O, 298 K) δ: 232.6 (C = S), 86.3 ((CH ₃ ) ₂ CH H (O) CH ₃ ); (CH ₃ ) ₂ CHCH (O) CH ₃ ); 17.7 ((CH ₃ ) ₂ CHCH (O) CH ₃ ); 17.6 ((CH ₃ ) ₂ CHCH (O) CH ₃ ); 15.8 ((CH ₃ ) ₂ CHCH (O) CH ₃ ) ppm.

 1 _._ 2J_ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

0.025 mole (5.05 g) of 2-bromoacetonitrile (Sigma-Aldrich) was added to a solution of 3. 11 g (0.026 mole) of the compound XAO obtained above in the previous step 1.1) in 25 ml of THF (Sigma-Aldrich), in an ice bath (very exothermic reaction). Once the addition was complete, the reaction medium was stirred at ambient temperature for 16 hours and then filtered. The filtrate was concentrated in vacuo and the reaction crude was purified by chromatography on silica (eluent petroleum ether / ethyl acetate: 80:20, v: v) to recover xanthate XA1 as a yellow oil (3.58 g, 71% yield).

2) Second step: preparation of methyl 6-cyano-2-methyl-4 - ((((3-methylbutan-2-yloxy) carbonothioylthio) hexanoate (mono-adduct of formula IV): XAlClN

.2_1_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ^_ J? E.Qty n _ methyl _ _ (Al.)

0.075 mol (10.6 g) of ethyl 2-methyl-4-pentenoate (Sigma-Aldrich), 120 ml of methanol (Sigma-Aldrich) and 0.0038 mol (0.369 g) of 97% sulfuric acid ( Sigma-Aldrich) were refluxed for 24 hours. The reaction mixture was then cooled, diluted with 100 ml diethyl ether (Sigma-Aldrich) and extracted with brine to a neutral pH. The organic phase was dried over magnesium sulfate (Sigma-Aldrich) and evaporated in vacuo. Methyl 2-methyl-4-pentenoate (Al) was obtained as a colorless liquid (7.15 g, 75% yield).

.2. ## STR1 ## 3.45 g (0.17 mmol) of the xanthate XA1 obtained above in substep 1.2). previous example, 2.01 g (0.016 mmol) of methyl 2-methyl-4-pentenoate A1 obtained above in the preceding substep 2.1), 0.90 g (0.0023 mmol) of dilauroyl peroxide (LPO); radical initiator) and 3.5 ml of toluene were mixed in a Schlenk tube. The mixture was then degassed by 3 vacuum freezings. After heating for 16 hours at a temperature of 90 ° C., the crude reaction product was purified by chromatography on silica (eluent ethyl acetate / hexane (2: 8, v: v)) to recover the mono-adduct XA1CN (3.96 g, 79% yield, yellow oil).

1 H NMR (300.13 MHz, CDCl ₃ , 298 K) δ (ppm): 5.59 - 5.47 (m, 1H, (CH ₃ ) ₂ CHCH (O) CH ₃ ), 3.94 - 3, 74 (m, 1H, SCH (CO) CH), 3.67 - 3.66 (m, 3H, C (O) CH ₃ ), 2.76 - 2.60 (m, 1H, SCH ₂ CH (CH 3) ₃ )), 2.54 - 2.45 (m, 2H, SCH ₂ CH ₂ CN), 2, 19 - 1.93 (m, 4H, SCH (CH ₂ CH ₂ CN) CH ₂ CH (CH ₃ ) ), 1.78 - 1.52 (m, 1H, (CH ₃ ) ₂ CHCH (O) CH ₃ ), 1.31 - 1.27 (m, 3H, CH (O) CH ₃ ), 1.20 - 1, 18 (d, 3H, SCH ₂ CH (CH ₃ )), 0.95 - 0.94 (m, 6H, (CH ₃ ) ₂ CHCH (O) CH ₃ ).

NMR ^ C ^ H} (75.47 MHz, CDCl _3, 298K) δ (ppm): 212.40 (C = O), 176.12 (C0 ₂ CH _3), 119.10 (CN), 86, 47 ((CH _{3) 2} CHÇ_H (0) CH _3), 51.94 (C0 ₂ C_h _3), 48.35 to 47.56 (SÇ_HCH ₂ CH ₂ N), 37.72 (SCHÇ_H ₂ CH ₂ CN) , 37.06 (SCHCH ₂ CH (CH ₃ )), 32.70 ((CH ₃ ) ₂ CHCH (O) CH ₃ ), 31.62 - 30.90 (SCH (CH ₂ CH (CH 3)), 18 , 28 - 15.75 ((CH ₃ ) ₂ CHCH (O) CH ₃ ) and SCHCH ₂ CH (CH ₃ )), 14.78 (SCH ₂ CH ₂ CN).

IR: 2971, 2876, 2247, 1734, 1460, 1237, 1044 cm ^-1 .

Molar mass: IC (CH ₄ ), MH ⁺ :

 Found: 332, 1369 g / mol,

 Calculated: 332, 1354 g / mol.

 3) Third step: preparation of 3- (4-methyl-5-oxotetrahydrothiophen-2-ynpropanenitrile (thiolactone of formula (I): TLD

2.05 g (0.0062 mole) of XA1CN obtained above in the preceding substep 2.2) were placed in a vacuum sealed Schlenk tube and heated to a temperature of 190 ° C for 24 hours. The reaction mixture was then cooled to room temperature and the volatiles formed were removed under vacuum. The thiolactone TL1 thus obtained in the form of a colorless oil was then purified on a silica chromatographic column (eluent hexane / ethyl acetate: 6: 4 (v: v)) (0.42 g, 40% yield). ). 1 H NMR (300.13 MHz, CDCl ₃ , 298 K) δ (ppm): 3.87 - 3.73 (m, 1H, CH (CH ₂ ) ₂ CN), 3.69 - 1.39 (m, 7H, C (O) CH (CH ₃ ) CH ₂ CH (CH ₂ ) ₂ ), 1.10 - 1.07 (m, 3H, CHCH ₃ ).

1H NMR (75.47 MHz, CDCl ₃ , 298K) δ (ppm): 209.06 - 207.98 (C = O), 118.76 (CH), 48.69 (CH ₃ ), from 45.46 to 44.88 (£ H (CH _{2) 2} CN), 40.30 to 38.74 (CH (CH ₃₎ CH ₂ CH), 32.09 to 31.67 (CH (CH ₂ CH ₂ CN), 16, 10-15.06 (CH ₂ CH ₂ CH ₂ CN), 15.12- 14.34 (CH ₃ H ₃ ).

IR: 2970, 2875, 2247, 1701, 1453, 756 cm ^-1 .

Molar mass: IC (CH ₄ ), MH ⁺ :

 Found: 170.0643 g / mol,

 Calc'd: 170.0640 g / mol.

 EXAMPLE 2 Synthesis of 2- (2- (4-methyl-5-oxotetrahydrothiophen-2-yl) butenindolin-1,3-dione (TL2) according to the Process According to the Invention In this example, the thiolactone of following formula (TL2):

1) First step: Preparation of S - ((1,3-dioxoisoindolin-2-yl) methyn-O- (3-methylbutan-2-yn) carbonodithioate (Xanthate of fine formula: ΓΧΑ2Ή

 XA2

0.021 mole (4.99 g) of 2- (bromomethyl) -H-isoindole-1,3 (2H) -dione (Sigma-Aldrich) was added to a solution of 4.04 g (0.020 mol) of compound XAO obtained in sub-step 1.1) of Example 1 in 35 ml acetone (Sigma-Aldrich), in an ice bath (very exothermic reaction). Once the addition was complete, the reaction medium was stirred at ambient temperature for 3 hours and then filtered. The filtrate was concentrated in vacuo to give the expected product XA 2 as a yellow oil (5.84 g, 91% yield) which will be used in the next step without purification.

2) Second step: preparation of methyl 6- (1,3-dioxoisoindolin-2-yl) -2-methyl-4 - ((((3-methylbutan-2-yloxy) carbonothio] thio) hexanoate (mono-adduct of formula ( IV): XA2PH)

 XA2PH

 3.82 g (0.012 mole) of the XA2 xanthate obtained above in the preceding step 1), 1.38 g (0.012 mole) of methyl 2-methyl-4-pentenoate A1 obtained above in step 2.1) of Example 1, and 0.64 g (0.0016 mole) of dilauroyl peroxide (LPO: radical initiator) were mixed in a Schlenk tube. The mixture was then degassed by 3 vacuum freezings. After heating for 16 hours at a temperature of 90 ° C., the crude reaction product was purified by chromatography on silica (eluent ethyl acetate / hexane (2: 8, v: v)) to recover the xanthate XA 2 which did not reacted on the one hand, and the mono-adduct XA2PH on the other hand (1.9 g, 91% yield, yellow oil).

1 H NMR (300.13 MHz, CDCl ₃ , 298 K) δ (ppm): 7.86 - 7.67 (m, 4H, H _ar ), 5.56 - 5.40 (m, 1H, (CH); ₃ ) ₂ CHCH (O) CH ₃ ), 5.22 - 4.07 (m, 1H, SCH (CO) CH), 3.86 - 3.70 (m, 3H, SCHCH ₂ CH ₂ N), 3.67 - 3.62 (m, 3H, C (O) CH ₃ ), 2.80 - 2.60 (m, 1H, SCHCH ₂ CH (CH ₃ )), 2.26 - 1.26 ( m, 5H, SCH (CH ₂ CH ₂ N-) CH ₂ CH (CH ₃ )), 1.29-1.15 (m, 6H, CH (O) CH ₃ and SCH ₂ CH (CH ₃ )), 0.92 - 0.86 (m, 6H, (CH ₃ ) ₂ CHCH (O) CH ₃ ). 1H NMR (75.47 MHz, CDCl ₃ , 298K) δ (ppm): 213.17 (C = S), 176.41 (CH ₂ CH ₃ ), 168.22 (C (O) N) (O), 133.90 to 123.24 (c_ _ar), 85.75 ((CH _{3) 2} CHCH (0) CH _3), 51.77 (C0 ₂ C_h _3), 46.87 to 46.17 (CH ₂ CH ₂ N), 37.18 (CHCH ₂ CH (CH ₃ )), 37.91-33.56 (SCH (CH ₂ ) ₂ N) CH ₂ CH (CH ₃ )), 32.69 ( (CH ₃ ) ₂ CHCH (O) CH ₃ ), 18.26 - 15.77 ((CH ₃ ) ₂ CHCH (O) CH ₃ ) and SCHCH ₂ CH (CH ₃ )).

IR: 2970, 1773, 1714, 1398, 1234, 1046, 721 cm ^-1 .

Molar mass: IC (CH ₄ ), MH ⁺ :

Found: 452.1572 g / mol, Calcd: 452.1565 g / mol.

Third Step: Preparation of 2- (2- (4-methyl-5-oxotetrahydrothiophen-2-ynthynisoindoline-1,3-dione (Thiolactone of Formula (1): TL2)

1.67 g (0.0037 mole) of XA2PH obtained above in the previous step 2) were placed in a vacuum-sealed Schlenk tube and heated to a temperature of 190 ° C for 24 hours. The reaction mixture was then dissolved in 3 ml of ethyl acetate and then precipitated in 200 ml of hexane. The white solid obtained was filtered on Buchner. The thiolactone TL2 was thus obtained in the form of a white solid (0.310 g, 30% yield). 1 H NMR (300.13 MHz, CDCl ₃ , 298 K) δ (ppm): 7.77-7.64 (m, 4H,

H _ar ), 3.80 - 3.61 (m, 3H, CH (CH ₂ CH ₂ N), 2.68 - 1.40 (m, 5H, C (O) CH (CH ₃ ) CH ₂ CH ( CH ₂ CH ₂ N) 1.11 - 1.06 (m, 3H, CHCH ₃ ).

1H NMR (75.47 MHz, CDCl ₃ , 298K) δ (ppm): 210.0 - 209.0 (C (O) S), 168.19 (N (C (O) CH) ₂ ), 134.17 - 123.33 (C _ar ), 48.33 (CH (CH ₃ )), 45.00 - 44.56 (CH ₂ CH (CH ₂ CH ₂ N)), 40.87 - 39 , 15 (CH ₂ CH (CH ₂ C_h ₂ N)), 36.47 to 35.40 (CH ₂ CH (CH ₂ CH ₂ N)), 15.20 to 14.38 (CH (C_h _3)).

IR: 2936, 1705, 1699, 1399, 1370, 724 cm ^-1 .

Molar mass: IC (CH ₄ ), MH ⁺ :

Found: 289.0782 g / mol, Calcd: 289.0773 g / mol.

Claims

 Process for the preparation of substituted thiolactones of formula (I)

in which :

R ¹ , R ² , R ³ and R ⁴ , which may be identical or different, represent a hydrogen atom or a group chosen from alkyl, acyl, aryl, heteroaryl, saturated or unsaturated cycloalkyl and saturated or unsaturated heterocycloalkyl groups; radicals R ¹ , R ² , R ³ and R ⁴ may also together form a saturated or unsaturated cycloalkyl or heterocycloalkyl group or an aryl or heteroaryl group; and

- R ⁵ , R ⁶ and R ⁷ , identical or different, are:

(a) selected from hydrogen, cyano (CN), alkyl, acyl, aryl, heteroaryl, aralkyl, saturated or unsaturated cycloalkyl, saturated heterocycloalkyl, or unsaturated, and a phthalimido group, said alkyl, acyl, aryl, heteroaryl, aralkyl, saturated or unsaturated cycloalkyl, saturated or unsaturated heterocycloalkyl and phthalimido groups which may be substituted with a group X selected from the following groups: P (0) (OR ⁸ ) (OR ^{8 '} ) in which the radicals R ⁸ and R ^8' , which may be identical or different, represent a hydrogen atom or an alkyl radical; C _n F _{2n +} i wherein n is an integer from 1 to 20; SiR ⁹ _p (OR ¹⁰ ) _3-p in which the radicals R ⁹ and R ¹⁰ , which may be identical or different, represent a hydrogen atom or an alkyl radical and p is an integer equal to 0, 1 or 2; BF ₃ M ⁺ wherein M = K or Na; B (OR ⁿ ) ₂ in which the two radicals R ¹¹ , which may be identical or different, represent a hydrogen atom or an alkyl radical or form a carbon ring with the two oxygen atoms to which they are bonded; OR ¹² wherein R ¹² represents a hydrogen atom or an alkyl, aryl or aralkyl radical; 0 (C = O) R ¹³ wherein R ¹³ represents a hydrogen atom or an alkyl, aryl or aralkyl radical; 0 (C = O) OR ¹⁴ wherein R ¹⁴ represents a hydrogen atom or an alkyl, aryl or aralkyl radical; N ⁺ R ¹⁵ R ¹⁵ R ^{15 "} A ^" in which the radicals R ¹⁵ , R ^{15 '} and R ^{15 "} , which may be identical or different, represent a hydrogen atom or an alkyl, aryl or aralkyl radical and A represents an atom of chlorine or bromine; NR ¹⁶ (C = O) R ^{16 '} in which the radicals R ¹⁶ and R ^16' , which are identical or different, represent a hydrogen atom or an alkyl or aryl radical or are connected together and form a a ring such as a pyrrolidone or caprolactam ring; NR ¹⁷ (C = O) OR ^{17 '} wherein R ¹⁷ and R ^17' , which may be identical or different, represent a hydrogen atom or an alkyl, aryl or aralkyl radical; CN; a halogen atom selected from Cl, F and Br; NCS; OCH ₂ -epoxy; COOR ¹⁸ wherein R ¹⁸ represents a hydrogen atom, an alkyl, aryl or aralkyl radical; CONR ¹⁹ R ^{19 '} wherein R ¹⁹ and R ^{19 ',} identical or different, represent a hydrogen atom or an alkyl or aryl radical; S0 ₂ R ²⁰ wherein R ²⁰ represents an alkyl or aryl radical; azide (N ₃ ) and alkyne; or

(b) as together they form a polymer chain P ¹ , or

(c) such that R ⁵ is different from the other two groups R ⁶ and R ⁷ , R ⁶ and R ⁷ have the same definition as in alternative (a) and R ⁵ is a thiolactone radical of the following formula:

in which R ¹ , R ² , R ³ , and R ⁴ have the same meaning as in formula (I) above, R ⁶ and R ⁷ have the same definition as in alternative (a), Z represents a divalent group chosen from a carbonyl group, a carbonate group, an alkylene group and an arylene group, and the # sign represents the attachment point of the thiolactone radical to the -CR ⁶ R ⁷ CH ₂ -thiolactone radical of the compound of formula (I ); said method being characterized in that it comprises at least the following steps:

 1) a step during which, in the presence of a radical initiator, a xanthate of the following formula (II) is reacted:

 (II)

 in which :

R ²¹ , R ²² , R ²³ and R ²⁴ , which may be identical or different, represent a hydrogen atom or a group chosen from alkyl, acyl, aryl, heteroaryl, alkene, alkyne, saturated or unsaturated cycloalkyl and saturated heterocycloalkyl groups; or unsaturated ¹ , the radicals R ²¹ , R ²² , R ²³ and R ²⁴ may also together form a saturated or unsaturated cycloalkyl or heterocycloalkyl group or an aryl or heteroaryl group;

 and

- R ^5a , R ⁶ and R ⁷ , identical or different, are:

(a ') selected from hydrogen, cyano (CN), alkyl, acyl, aryl, heteroaryl, aralkyl, saturated or unsaturated cycloalkyl, saturated heterocycloalkyl or unsaturated and a phthalimido group, said alkyl, acyl, aryl, heteroaryl, aralkyl, saturated or unsaturated cycloalkyl, saturated or unsaturated heterocycloalkyl and phthalimido groups which may be substituted with a group X selected from the following groups: P (0) (OR ⁸ ) (OR ^{8 '} ) in which the radicals R ⁸ and R ^8' , which may be identical or different, represent a hydrogen atom or an alkyl radical; C _n F ₂ n + i wherein n is an integer from 1 to 20; SiR ⁹ _p (OR ¹⁰ ) 3 _-p in which the radicals R ⁹ and R ¹⁰ , which may be identical or different, represent a hydrogen atom or an alkyl radical and p is an integer equal to 0, 1 or 2; BF ₃ M ⁺ wherein M = K or Na; B (OR ⁿ ) ₂ in which the two radicals R ¹¹ , which are identical or different, represent a hydrogen atom, an alkyl radical or form a carbon ring with the two oxygen atoms to which they are bonded; OR ¹² wherein R ¹² represents a hydrogen atom or an alkyl, aryl or aralkyl radical; 0 (C = O) R ¹³ wherein R ¹³ represents a hydrogen atom or an alkyl, aryl or aralkyl radical; 0 (C = O) OR ¹⁴ wherein R ¹⁴ represents a hydrogen atom or an alkyl, aryl or aralkyl radical; N ⁺ R ¹⁵ R ¹⁵ R ^{15 "} A ^" in which the radicals R ¹⁵ , R ^{15 '} and R ^{15 "} , which may be identical or different, represent a hydrogen atom or an alkyl, aryl or aralkyl radical and A represents an atom of chlorine or bromine; NR ¹⁶ (C = O) R ^{16 '} in which the radicals R ¹⁶ and R ^16' , which are identical or different, represent a hydrogen atom or an alkyl or aryl radical or are connected together and form a a ring such as a pyrrolidone or caprolactam ring; NR ¹⁷ (C = O) OR ^{17 '} wherein R ¹⁷ and R ^17' , which may be identical or different, represent a hydrogen atom or an alkyl, aryl or aralkyl radical; CN; a halogen atom selected from Cl, F and Br; NCS; OCH ₂ -epoxy; COOR ¹⁸ wherein R ¹⁸ represents a hydrogen atom, an alkyl, aryl or aralkyl radical; CONR ¹⁹ R ^{19 '} wherein R ¹⁹ and R ^{19 ',} identical or different, represent a hydrogen atom or an alkyl or aryl radical; S0 ₂ R ²⁰ wherein R ²⁰ represents an alkyl or aryl radical; azide (N ₃ ) and alkyne; or

(b ') as together form a polymer chain P ¹ ; or

(c ') such that R ^5a is different from the other two groups R ⁶ and R ⁷ , R ⁶ and R ⁷ have the same definition as in the alternative (a') and R ^5a is a xanthate radical of formula:

in which R, R, R and R have the same meaning as in formula (II) above, R ⁶ and R ⁷ have the same definition as in alternative (a '), Z represents a divalent group selected from a carbonyl group, a carbonate group, an alkylene group and an arylene group, and the sign # represents the point of attachment of the xanthate radical to the -CR ⁶ R ⁷ -xanthate radical of the compound of formula (II); with a monomer comprising at least one ethylenic unsaturation of formula (III) below:

 (III) wherein:

R ²⁵ represents a group selected from saturated or unsaturated alkyl, acyl, aryl, heteroaryl, aralkyl, cycloalkyl and saturated or unsaturated heterocycloalkyl groups;

Y is an oxygen atom or an NR ²⁶ radical in which R ²⁶ represents a hydrogen atom or an alkyl group, and preferably an oxygen atom; and

- R ¹ , R ² , R ³ and R ⁴ have the same meaning as in formula (I) above;

 to form a mono-adduct of formula (IV) below:

 (IV) wherein:

- R ¹ , R ² , R ³ and R ⁴ have the same meaning as in formula (I) above; - R ²¹ , R ²² , R ²³ and R ²⁴ have the same meaning as in formula (II) above; and

R ²⁵ has the same meaning as in formula (III) above; and

- R ^5b , R ⁶ and R ⁷ , identical or different, are:

(a ") selected from hydrogen, cyano (CN), alkyl, acyl, aryl, heteroaryl, aralkyl, saturated or unsaturated cycloalkyl, saturated heterocycloalkyl or unsaturated and a phthalimido group, said alkyl, acyl, aryl, heteroaryl, aralkyl, saturated or unsaturated cycloalkyl, saturated or unsaturated heterocycloalkyl and phthalimido groups which may be substituted with a group X selected from the following groups: P (0) (OR ⁸ ) (OR ⁸ ) in which the radicals R ⁸ and R ^{8 '} , which may be identical or different, represent a hydrogen atom or an alkyl radical; C _n F ₂ n + 1 in which n is an integer ranging from 1 to 20 ; SiR ⁹ _p (oR ¹⁰⁾ 3 _-p wherein the radicals R ⁹ and R ^10, identical or different, represent a hydrogen atom or an alkyl radical and p is an integer 0, 1 or 2; BF ₃ M ⁺ in which M = K or Na; B (OR ⁿ ) ₂ in which the two radicals R ¹¹ , id entic or different, represent a hydrogen atom, an alkyl radical or form a carbon ring with the two oxygen atoms to which they are attached; OR ¹² wherein R ¹² represents a hydrogen atom or an alkyl, aryl or aralkyl radical; 0 (C = O) R ¹³ wherein R ¹³ represents a hydrogen atom or an alkyl, aryl or aralkyl radical; 0 (C = O) OR ¹⁴ wherein R ¹⁴ represents a hydrogen atom or an alkyl, aryl or aralkyl radical; N ⁺ R ¹⁵ R ¹⁵ R ^{15 "} A ^" in which the radicals R ¹⁵ , R ^{15 '} and R ^{15 "} , which may be identical or different, represent a hydrogen atom or an alkyl, aryl or aralkyl radical and A represents an atom of chlorine or bromine; NR ¹⁶ (C = O) R ^{16 '} in which the radicals R ¹⁶ and R ^16' , which are identical or different, represent a hydrogen atom or an alkyl or aryl radical or are connected together and form a a ring such as a pyrrolidone or caprolactam ring; NR ¹⁷ (C = O) OR ^{17 '} wherein R ¹⁷ and R ^17' , which may be identical or different, represent a hydrogen atom or an alkyl, aryl or aralkyl radical; CN; a halogen atom selected from Cl, F and Br; NCS; OCH ₂ -epoxy; COOR ¹⁸ wherein R ¹⁸ represents a hydrogen atom, a alkyl, aryl or aralkyl radical; CONR ¹⁹ R ^{19 '} wherein R ¹⁹ and R ^19' , which may be identical or different, represent a hydrogen atom or an alkyl or aryl radical; S0 ₂ R ² ° wherein R ²⁰ represents an alkyl or aryl radical; azide (N ₃ ) and alkyne; or

(b ") as together form a polymer chain P ¹ , or

(c ") such that R ^5b is different from the other two groups R ⁶ and R ⁷ , R ⁶ and R ⁷ have the same definition as in alternative (a"), and R ^5b is a mono-adduct radical of formula next :

in which R ¹ , R ² , R ³ , R ⁴ , R ²¹ , R ²² , R ²³ , R ²⁴ , Y and R ²⁵ have the same meaning as in formula (IV) above, R ⁶ and R ⁷ have the same definition as in alternative (a "), Z represents a divalent group selected from a carbonyl group, a carbonate group, an alkylene group and an arylene group, and the sign # represents the anchor point of the mono radical -adducted with the radical - CR ⁶ R ⁷ -monoadduct of the compound of formula (IV);

 2) a step of thermolysis of the mono-adduct of formula (IV) obtained above in the preceding step to form a substituted thiolactone of formula (I) corresponding.

2. Method according to claim 1, characterized in that R ²¹ , R ²² , R ²³ and R ²⁴ represent a hydrogen atom or an alkyl group.

3. Method according to claim 1 or 2, characterized in that R ⁵ is a cyano group or a phthalimido group.

4. Process according to any one of the preceding claims, characterized in that R ²⁵ is an alkyl group.

5. Process according to any one of the preceding claims, characterized in that R ¹ , R ² , R ³ and R ⁴ represent a hydrogen atom or an alkyl group.

 6. Process according to any one of the preceding claims, characterized in that it leads to the formation of a thiolactone of formula (I) chosen from:

 3- (4-methyl-5-oxotetrahydrothiophen-2-yl) propanenitrile (TL1), and

2- (2- (4-methyl-5-oxotetrahydrothiophen-2-yl) ethyl) isoindoline-1,3-dione (TL2).

 7. Process according to any one of the preceding claims, characterized in that the step 1) of preparation of the mono-adduct of formula (IV) is carried out without solvent, in water or in an organic solvent.

 8. Method according to any one of the preceding claims, characterized in that the radical initiator used in step 1) is chosen from organic peroxides, azo derivatives and redox systems.

 9. Method according to any one of the preceding claims, characterized in that step 1) is carried out at a temperature ranging from 10 to 140 ° C.

 10. Process according to any one of the preceding claims, characterized in that step 2) of thermolysis is carried out without solvent.

 11. Method according to any one of the preceding claims, characterized in that the temperature of the step 2) of thermolysis is between 40 and 210 ° C.

 12. Process according to any one of the preceding claims, characterized in that step 2) of thermolysis is carried out in a closed container and under vacuum.

13. Substituted thiolactones obtained according to a process as defined in any one of the preceding claims, and corresponding to the following formula (Γ):

 (Ι ')

 in which :

- R ^{1 '} , R ^2' , R ^{3 '} and R ^4' , which may be identical or different, represent a hydrogen atom or a group chosen from alkyl, acyl, aryl, heteroaryl, saturated or unsaturated cycloalkyl and saturated heterocycloalkyl groups; or unsaturated, the radicals R ^{1 '} , R ^2' , R ^{3 '} and R ^4' may also together form a saturated or unsaturated cycloalkyl or heterocycloalkyl group or an aryl or heteroaryl group; and

- R ^{5 '} , R ^6' and R ^{7 '} are defined according to one of two options (i) or (ii):

(I)

R ^{5 '} is selected from cyano group and phthalimido group; and

R ^{6 '} and R ^7' , which may be identical or different, are chosen from a hydrogen atom, an alkyl group, an acyl group, an aryl group, a heteroaryl group, an aralkyl group, a saturated or unsaturated cycloalkyl group and a saturated or unsaturated heterocycloalkyl group, said alkyl, acyl, aryl, heteroaryl, aralkyl, saturated or unsaturated cycloalkyl and saturated or unsaturated heterocycloalkyl groups which may be substituted with a group X selected from the following groups: P (0) (OR ⁸ ) (OR ⁸ ) in which the R ⁸ and R ^{8 '} radicals, which may be identical or different, represent a hydrogen atom or an alkyl radical; C _n F ₂ n + i wherein n is an integer from 1 to 20; SiR ⁹ _p (OR ¹⁰ ) _3- p in which the radicals R ⁹ and R ¹⁰ , which may be identical or different, represent a hydrogen atom or an alkyl radical and p is an integer equal to 0, 1 or 2; BF ₃ M ⁺ wherein M = K or Na; B (OR ⁿ ) ₂ in which the two radicals R ¹¹ , which may be identical or different, represent a hydrogen atom or an alkyl radical or form a carbon cycle with both oxygen atoms to which they are linked; OR ¹² wherein R ¹² represents a hydrogen atom or an alkyl, aryl or aralkyl radical; 0 (C = O) R ¹³ wherein R ¹³ represents a hydrogen atom or an alkyl, aryl or aralkyl radical; 0 (C = O) OR ¹⁴ wherein R ¹⁴ represents a hydrogen atom or an alkyl, aryl or aralkyl radical; N ⁺ R ¹⁵ R ¹⁵ R ^{15 "} A ^" in which the radicals R ¹⁵ , R ^{15 '} and R ^{15 "} , which may be identical or different, represent a hydrogen atom or an alkyl, aryl or aralkyl radical and A represents an atom of chlorine or bromine; NR ¹⁶ (C = O) R ^{16 '} in which the radicals R ¹⁶ and R ^16' , which are identical or different, represent a hydrogen atom or an alkyl or aryl radical or are connected together and form a a ring such as a pyrrolidone or caprolactam ring; NR ¹⁷ (C = O) OR ^{17 '} wherein R ¹⁷ and R ^17' , which may be identical or different, represent a hydrogen atom or an alkyl, aryl or aralkyl radical; CN; a halogen atom selected from Cl, F and Br; NCS; OCH ₂ -epoxy; COOR ¹⁸ wherein R ¹⁸ represents a hydrogen atom, an alkyl, aryl or aralkyl radical; CONR ¹⁹ R ^{19 '} wherein R ¹⁹ and R ^{19 ',} identical or different, represent a hydrogen atom or an alkyl or aryl radical; S0 ₂ R ²⁰ wherein R ²⁰ represents an alkyl or aryl radical; azide (N ₃ ) and alkyne; or

(ii) R ^{5 '} , R ^6' and R ^{7 '} are such that together they form a polymer chain P ¹ .

 14. Thiolactones according to claim 13, characterized in that they are chosen from:

3- (4-methyl-5-oxotetrahydrothiophen-2-yl) propanenitrile (TL1), and

2- (2- (4-methyl-5-oxotetrahydrothiophen-2-yl) ethyl) isoindoline-1,3-dione (TL2).

 15. Use of at least one substituted thiolactone of formula (Γ) as defined in any one of claims 13 or 14, for the synthesis of polymers or for the functionalization of particles, flat surfaces or polymers.