Patent ID: 8314271

Claim:
A process for producing a compound of formula (I): wherein z represents 1 or 0, and each R 1 , independently from each other, represents a hydrogen atom or a methyl or ethyl group, or the two R 1 taken together represent a (CH 2 ) m group, m representing 3, 4, or 5; each R 2 , independently from each other, represents a hydrogen atom or a methyl or ethyl group, or the two R 2 taken together represent a (CH 2 ) m group, m representing 3, 4, or 5; and R 3 represents a phenyl group optionally substituted, a saturated or unsaturated C 5 -C 6 cyclic hydrocarbon moiety optionally substituted, or a CH(R 4 ) 2 or R 4 CH═CR 4 moiety, R 4 representing a C 1 -C 6 alkyl or alkenyl group optionally substituted; and the substituents of said R 3 group are one, two or three C 1 -C 3 alkyl, alkenyl or alkoxy groups; wherein the process comprises reacting the corresponding compound of formula (II): wherein z, R 1 , R 2 and R 3 are defined as in formula (I) and x represents an integer comprised between 2 and 10; with at least one metal compound of formula M(R 5 ) (n-2y) (R 6 ) y , wherein y is 0, 1 or 2; wherein: M represents Zr or Ti, and n is 4, or Al and n is 3, or Mo(O 2 ) 2 and n is 2; R 5 represents, independently from each other, a C 1 -C 6 alkoxylate group or a C 5 -C 8 1,3-diketonate, and R 6 represents a 1,2- or 1,3-dialkoxylate or a 1,2-diphenoxylate.