REDUCTION OF CARBONYL COMPOUNDS VIA HYDROSILYLATION. V. SYNTHESIS OF OPTICALLY ACTIVE ALLYLIC ALCOHOLS VIA REGIOSELECTIVE ASYMMETRIC HYDROSILALATION

Article abstract of DOI:10.1016/0022-328X(82)80001-6

Regioselective asymmetric reduction of prochiral α,β-unsaturated ketones to optically active allylic alcohols was performed via hydrosilylation catalyzed by a rhodium(I) complex with (+)-BMPP, (+)-DIOP and (-)-DIOP as chiral ligands.The allylic alcohols with optical purity up to 69percent e.e. were obtained in good yields.The extent of asymmetric induction was found to depend on the stereoelectronic matching of the chiral ligand, ketone and hydrosilane employed.In the asymmetric reduction of (R)-carbone, leading to carveol, the extent of asymmetric induction was found todepend markedly on the ligand/rhodium ratio.Either trans-(5R,1S)-carveol or cis-(5R,1R)-carveol was obtained with good stereoselectivity by using (-)-DIOP or (+)-DIOP as chiral ligand, and it turned out that the chiral center present in carbone had only a slight influence on the asymmetric induction by the chiral catalysts.