摘要:
Compounds of the formula I, in the form of their racemates, mixtures of stereoisomers or mainly pure stereoisomers in which
Y is C 1 -C 4 alkylene or -SiR 1 R 2 -; X is a carbon atom and A 1 and A 2 independently of one another are hydrogen, C 1 -C 12 alkyl, C 2 -C 12 alkenyl, C 3 -C 8 cycloalkyl, C 3 -C 8 cycloalkenyl, C 3 -C 8 cycloalkyl-C 1 -C 4 alkyl, C 3 -C 8 cycloalkenyl-C 1 -C 4 alkyl, C 6 -C 10 aryl or C 7 -C 14 aralkyl; or X is a silicon atom and A 1 and A 2 independently of one another are C 1 -C 12 alkyl, C 3 -C 8 cycloalkyl, C 3 -C 8 cycloalkyl-C 1 -C 4 alkyl, C 6 -C 10 aryl or C 7 -C 14 aralkyl; A 3 and A 4 independently of one another are hydrogen, C 1 -C 12 alkyl, C 3 -C 8 cycloalkyl, C 3 -C 8 -cycloalkyl-C 1 -C 4 alkyl, C 6 -C 10 aryl or C 7 -C 14 aralkyl; and R 1 and R 2 independently of one another are C 1 -C 6 alkyl, cyclohexyl, phenyl or benzyl, are ligands for metal complexes of the eighth sub-group of the Periodic Table of the Elements, which are suitable as catalysts for asymmetric hydrogenations and transfer hydrogenations of prochiral compounds having carbon/carbon or carbon/heteroatom multiple bonds.