| abstract |
Compounds of formula I wherein the groups (R1) 2P (CH2)m and (R1) 2P (CHz) n are in o- or m-position to each other and the substituents R1 are identical or different radicals, m and n are each independently of the other 0 or 1, R1 is linear or branched C1-C12alkyl, unsubstituted C5-C6cycloalkyl or C5-C6cycloalkyl which is substituted by C1-C4alkyl or C1-C4alkoxy, or is phenyl or benzyl, or both substituents R1 in a group (R1)2P together are o,o'-diphenylene, -R2-X- is a bond or -(C xH2x-O) y-, or X- is O- and R2 is C1-C6alkylene, x is an integer from 2 to 6 and y is an integer from 2 to 6, R3 is C2-C18alkylene, phenylene or benzylene, and R4 is C1-C6alkyl or phenyl, can be applied to solid carriers, such as silica gel or aerosils, and complexed with rhodium or iridium compounds. These materials are heterogeneous and separable catalysts for the asymmetrical hydrogenation of prochiral compounds containing carbon double bonds or carbon/hetero atom double bonds, for example ketones and imines. |