Patent ID: 7989665

Claim:
A process for the reduction by molecular hydrogenation, of a substrate containing one or two ester or lactone functional groups into its corresponding alcohol or diol, the process comprising reducing said substrate with molecular hydrogen in the presence of a base and at least one catalyst or pre-catalyst in the form of a ruthenium complexes of formula 1 or 2 [Ru(L4)Y 2 ] (1) [Ru(L4)(X) n (Y) 2-n ](Z) n (2) wherein: L4 is a ligand of formula (4-A): R 2 and R 3 , when taken separately, represent, simultaneously or independently, a linear, branched or cyclic C 1 to C 8 alkyl or alkenyl group optionally substituted, a C 6 to C 10 aromatic group optionally substituted, or an OR 20 ′ or NR 2 ′R 3 ′ group, R 2 ′ and R 3 ′ being a C 1 to C 8 alkyl or alkenyl group; or the groups R 2 and R 3 , when taken together, form a saturated or unsaturated ring optionally substituted, having 4 to 10 atoms and including the phosphorus atom to which the R 2 and R 3 groups are bonded ; R 9 , R 10 and R 11 , taken separately, represent, simultaneously or independently, a hydrogen atom, a C 1 -C 8 linear, branched or cyclic alkyl or alkenyl group optionally substituted or a C 6 to C 10 aromatic group optionally substituted; two adjacent or geminal R 9 , taken together, may form preferably C 5 to C 8 , ring including the carbon atom to which the R 9 groups are bonded; an R 10 group and an R 9 group, in α-position to the same N atom, can be bonded together to form a C 4 - to C 6 ring; two adjacent R 11 groups can be bonded together to form a C 6 to C 10 aromatic ring optionally substituted or a C 5 to C 12 metallocediyl group optionally substituted and including the carbon atom to which the R 11 groups are bonded; and k are, simultaneously or independently, equal to 0 or 1; each Y represents, simultaneously or independently, CO, a hydrogen or halogen atom, a hydroxyl group, or a C 1 -C 6 alkoxy or carboxylic radical, or a BH 4 or ALH 4 group; X represents a C 3 -C 30 mono-phosphine or a solvent; Z represents a non-coordinated anion; and n is 0, 1 or 2 and the substrate is a compound of formula (I) wherein R a and R b represent, simultaneously or independently, a linear, branched or cyclic C 1 -C 30 aromatic, alkyl or alkenyl group optionally substituted; or R a and R b are bonded together and form a C 4 -C 20 saturated or unsaturated group, optionally substituted; and wherein the substituents of R a and R b are a COOR c , group, one, two or three halogen, OR c , NR c 2 or R c groups, in which R c is a hydrogen atom, a halogenated C 1 - to C 2 groups or a C 1 to C 10 cyclic, linear or branched alkyl, or alkenyl group.