Asymmetric hydroformylation of styrene catalyzed by furanoside phosphine-phosphite-Rh(I) complexes

A series of phosphine-phosphite ligands, derived from inexpensive D-(+)-xylose, were tested in the Rh-catalyzed asymmetric hydroformylation of styrene. Systematic variation of the phosphite moiety revealed a remarkable effect on the selectivity of the hydroformylation catalysts. High regioselectivities for 2-phenylpropanal (up to 95%) and moderate enantioselectivity were found under mild reaction conditions (25-40degreesC. 25 bar of syn gas). The hydroformylation results are explained by the solution structures of the intermediate species formed under hydroformylation conditions. (C) 2002 Published by Elsevier Science Ltd.