A transfer hydrogenation of a compound of formula to a compound of formula wherein R signifies -CH 3 or -CH 2 CH 3, characterized in that the hydrogenation is carried out in the presence of a) an amino-amide-transition-metal catalyst of formula MX[Z-(-H)] wherein M is chosen from the group consisting of Ir, Rh and Ru, and X signifies H or a halogen atom, and Y is chosen from the group consisting of pentamethylcyclopentadienyl, benzene, p-cymene, toluene, anisole, xylene, 1,3,5-trimethylbenzene, p-dicyclohexylbenzene, naphthalene and tetralin, and Z signifies a group of formula or and the transition metal M is complexed to Z via the amine and the amide of Z; and the monosulphonylated diamine Z is present in the complex as a monoanion and is accordingly denoted in formula III as "Z-(-H)"; wherein R 1 signifies C 1 -C 2 -alkyl which may be substituted with one or more fluorine atoms, C 2 -C 6 -alkenyl, C 2 -C 6 -alkynyl, C 4 -C 7 -cycloalkyl, aryl which may be substituted, heteroaryl, or camphor-10-yl, and R 2 and R 3 each independently signify hydrogen, C 1 -C 2 -alkyl, C 4 -C 7 -cycloalkyl, or aryl which may be substituted, and R 4 signifies hydrogen or C 1 -C 2 -alkyl, and R 5 signifies hydrogen or C 1 -C 2 -alkyl, and R 6 signifies hydrogen or C 1 -C 2 -alkyl, and n signifies 0,1,2 or 3, and m signifies 0,1,2 or 3, and with the proviso that in formula the sum of n and m is 3 or 4, and b) a H 2 donor, and wherein the hydrogenation is carried out by using at least one solvent which also serves as hydrogen donor. a) an amino-amide-transition-metal catalyst of formula MX[Z-(-H)] wherein M is chosen from the group consisting of Ir, Rh and Ru, and X signifies H or a halogen atom, and Y is chosen from the group consisting of pentamethylcyclopentadienyl, benzene, p-cymene, toluene, anisole, xylene, 1,3,5-trimethylbenzene, p-dicyclohexylbenzene, naphthalene and tetralin, and Z signifies a group of formula or and the transition metal M is complexed to Z via the amine and the amide of Z; and the monosulphonylated diamine Z is present in the complex as a monoanion and is accordingly denoted in formula III as "Z-(-H)"; wherein R 1 signifies C 1 -C 2 -alkyl which may be substituted with one or more fluorine atoms, C 2 -C 6 -alkenyl, C 2 -C 6 -alkynyl, C 4 -C 7 -cycloalkyl, aryl which may be substituted, heteroaryl, or camphor-10-yl, and R 2 and R 3 each independently signify hydrogen, C 1 -C 2 -alkyl, C 4 -C 7 -cycloalkyl, or aryl which may be substituted, and R 4 signifies hydrogen or C 1 -C 2 -alkyl, and R 5 signifies hydrogen or C 1 -C 2 -alkyl, and R 6 signifies hydrogen or C 1 -C 2 -alkyl, and n signifies 0,1,2 or 3, and m signifies 0,1,2 or 3, and with the proviso that in formula the sum of n and m is 3 or 4, and M is chosen from the group consisting of Ir, Rh and Ru, and X signifies H or a halogen atom, and Y is chosen from the group consisting of pentamethylcyclopentadienyl, benzene, p-cymene, toluene, anisole, xylene, 1,3,5-trimethylbenzene, p-dicyclohexylbenzene, naphthalene and tetralin, and Z signifies a group of formula or and the transition metal M is complexed to Z via the amine and the amide of Z; and the monosulphonylated diamine Z is present in the complex as a monoanion and is accordingly denoted in formula III as "Z-(-H)"; wherein R 1 signifies C 1 -C 2 -alkyl which may be substituted with one or more fluorine atoms, C 2 -C 6 -alkenyl, C 2 -C 6 -alkynyl, C 4 -C 7 -cycloalkyl, aryl which may be substituted, heteroaryl, or camphor-10-yl, and R 2 and R 3 each independently signify hydrogen, C 1 -C 2 -alkyl, C 4 -C 7 -cycloalkyl, or aryl which may be substituted, and R 4 signifies hydrogen or C 1 -C 2 -alkyl, and R 5 signifies hydrogen or C 1 -C 2 -alkyl, and R 6 signifies hydrogen or C 1 -C 2 -alkyl, and n signifies 0,1,2 or 3, and m signifies 0,1,2 or 3, and with the proviso that in formula the sum of n and m is 3 or 4, and R 1 signifies C 1 -C 2 -alkyl which may be substituted with one or more fluorine atoms, C 2 -C 6 -alkenyl, C 2 -C 6 -alkynyl, C 4 -C 7 -cycloalkyl, aryl which may be substituted, heteroaryl, or camphor-10-yl, and R 2 and R 3 each independently signify hydrogen, C 1 -C 2 -alkyl, C 4 -C 7 -cycloalkyl, or aryl which may be substituted, and R 4 signifies hydrogen or C 1 -C 2 -alkyl, and R 5 signifies hydrogen or C 1 -C 2 -alkyl, and R 6 signifies hydrogen or C 1 -C 2 -alkyl, and n signifies 0,1,2 or 3, and m signifies 0,1,2 or 3, and with the proviso that in formula the sum of n and m is 3 or 4, and b) a H 2 donor, and