Thiocarbonylthio compounds as chain transfer agents suitable for raft polymerization

A process for the preparation of a compound of formula (I):

• wherein
• R1 is aryl or —SC1-20 alkyl, wherein the aryl and —SC1-20 alkyl can be optionally substituted with 1-5 substituents independently selected in each occurrence thereof from the group consisting of H, C1-6 alkyl, halogen, —OR5, —SR5, and —NR6R7,
• R2 is C1-6 alkyl,
• R3 is H or C1-6 alkyl,
• R4 is H or C1-6 alkyl,
• R5 is H or C1-6 alkyl,
• R6 is H or C1-6 alkyl, and
• R7 is H or C1-6 alkyl,
• with the proviso that when R4 is methyl then R1 is not aryl or —S-t-Bu, said process comprising:
• providing a first intermediate compound of formula (II):
• wherein A1⊕ is a suitable cation;
• and
• forming the compound of formula (I) from the first intermediate compound of formula (II).

A process for the synthesis of a polymer comprising:

• providing a monomer composition;
• providing a chain transfer agent of formula (I):
• wherein
• R1 is aryl or —SC1-20 alkyl, wherein aryl and —SC1-20 alkyl can be optionally substituted with 1-5 substituents independently selected in each occurrence thereof from the group consisting of H, C1-6 alkyl, halogen, —OR5, —SR5, and —NR6R7,
• R2 is C1-6 alkyl,
• R3 is H or C1-6 alkyl,
• R4 is H or C1-6 alkyl,
• R5 is H or C1-6 alkyl,
• R6 is H or C1-6 alkyl, and
• R7 is H or C1-6 alkyl;
• and
• polymerizing the monomer composition through controlled free radical polymerization with the chain transfer agent to form the polymer.

A compound having the structure of formula (I):

• wherein
• R1 is aryl, heteroaryl, heterocyclyl, or —SC1-20 alkyl, wherein the aryl, heteroaryl, heterocyclyl, and —SC1-20 alkyl can be optionally substituted with 1-5 substituents independently selected in each occurrence thereof from the group consisting of H, C1-6 alkyl, halogen, —OR5, —SR5, and —NR6R7,
• R2 is C1-6 alkyl,
• R3 is H or C1-6 alkyl,
• R4 is H or C1-6 alkyl,
• R5 is H, C1-6 alkyl, or —C(O)—(CH2) n-COOH,
• R6 is H or C1-6 alkyl,
• R7 is H or C1-6 alkyl, and
• n is 1, 2, 3, 4, 5, or 6,
• with the proviso that when R4 is methyl then R1 is not aryl or —S-t-Bu.

A process for the preparation of a compound of formula (I):

• wherein
• R1 is aryl, heteroaryl, heterocyclyl, or —SC1-20 alkyl, wherein the aryl, heteroaryl, heterocyclyl, and —SC1-20 alkyl can be optionally substituted with 1-5 substituents independently selected in each occurrence thereof from the group consisting of H, C1-6 alkyl, halogen, —OR5, —SR5, and —NR6R7,
• R2 is C1-6 alkyl,
• R3 is H or C1-6 alkyl,
• R4 is H or C1-6 alkyl,
• R5 is H, C1-6 alkyl, or —C(O)—(CH2) n-COOH,
• R6 is H or C1-6 alkyl,
• R7 is H or C1-6 alkyl, and
• n is 1, 2, 3, 4, 5, or 6,
• with the proviso that when R4 is methyl then R1 is not aryl or —S-t-Bu, said process comprising:
• providing a first intermediate compound of formula (II):
• wherein A1⊕ is a suitable cation;
• and
• forming the compound of formula (I) from the first intermediate compound of formula (II).

A process for the synthesis of a polymer comprising:

• providing a monomer composition;
• providing a chain transfer agent of formula (I):
• wherein
• R1 is aryl, heteroaryl, heterocyclyl, or —SC1-20 alkyl, wherein the aryl, heteroaryl, heterocyclyl, and —SC1-20 alkyl can be optionally substituted with 1-5 substituents independently selected in each occurrence thereof from the group consisting of H, C1-6 alkyl, halogen, —OR5, —SR5, and —NR6R7,
• R2 is C1-6 alkyl,
• R3 is H or C1-6 alkyl,
• R4 is H or C1-6 alkyl,
• R5 is H, C1-6 alkyl, or —C(O)—(CH2) n-COOH,
• R6 is H or C1-6 alkyl,
• R7 is H or C1-6 alkyl, and
• n is 1, 2, 3, 4, 5, or 6;
• and
• polymerizing the monomer composition through controlled free radical polymerization with the chain transfer agent to form the polymer.