New chiral diphosphinites: synthesis of Rh complexes. Heterogenisation on zeolites

New diphosphinite ligands derived from (2S,4R), (2S,4S)-1-benzyl-4-hydroxy- 4-phenyl-2-(1-diphenylmethyl)-pyrrolidinylmethanol and (2S,4R), (2S,4S)-1-( 3-triethoxysilyl)propylaminocarbonyl-4-hydroxy-4-phenyl-2-(1,1-diphenylmeth yl)pyrrolidinylmethanol have been prepared in high yields (60-80%) and reac ted with [RhCl(cod)](2) to yield cationic [Rh(diphosphinite)(cod)](+) compl exes. Those metal complexes bearing a triethoxysilyl group were covalently bonded to USY-zeo-lite by controlled hydrolysis and Rh-heterogenised comple xes were obtained. A comparative study (homogeneous versus supported) for t he catalytic activity and selectivity in hydrogenation and hydroformylation reactions was made, obtaining an enhanced performance for heterogenised ca talysts; moreover, those catalysts can be recycled in successive runs, by a simple filtration, without a significant loss of activity. (C) 1999 Elsevi er Science S.A. All rights reserved.