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

Abstract

Abstract New diphosphinite ligands derived from (2 S ,4 R ), (2 S ,4 S )-1-benzyl-4-hydroxy-4-phenyl-2-(1,1-diphenylmethyl)pyrrolidinylmethanol and (2 S ,4 R ), (2 S ,4 S )-1-(3-triethoxysilyl)propylaminocarbonyl-4-hydroxy-4-phenyl-2-(1,1-diphenylmethyl)pyrrolidi nylmethanol have been prepared in high yields (60–80%) and reacted with [RhCl(cod)] 2 to yield cationic [Rh(diphosphinite)(cod)] + complexes. Those metal complexes bearing a triethoxysilyl group were covalently bonded to USY-zeolite by controlled hydrolysis and Rh-heterogenised complexes were obtained. A comparative study (homogeneous versus supported) for the catalytic activity and selectivity in hydrogenation and hydroformylation reactions was made, obtaining an enhanced performance for heterogenised catalysts; moreover, those catalysts can be recycled in successive runs, by a simple filtration, without a significant loss of activity.