Asymmetric catalytic hydroformylation of styrene: stereoselective ferrocenylethyldiphosphine rhodium catalysts

The use of a variety of chiral ferrocenylethyl diphosphines and a rhodium(I ) precursor for the asymmetric hydroformylation of styrene is described. So me of these catalysts yield the chiral 2-phenylpropionic aldehyde with high enantioselectivity. The selectivity and activity of the catalysts are infl uenced by the substitution pattern of the phosphines. High enantioselectivi ty was achieved even at high reaction temperatures with a dialkylaryl-alkyl diaryl diphosphine ligand. o-Anisyl substituents at the side-chain phosphor us yield optical inductions of up to 76% ee, but at low conversion rates. ( C) 2000 Elsevier Science S.A. All rights reserved.