ENANTIOSELECTIVE REDUCTION OF KETONES WITH BORANE, CATALYZED BY (S)-(-)-PROLINE OR (S)-(+)-PROLINOL

Article abstract of DOI:10.1016/S0957-4166(00)80075-0

The enantioselective reduction of ketones by borane in the presence of catalytic amounts of (S)-(-)-proline or (S)-(+)-prolinol as chiral auxiliaries has been investigated.The alcohols possess all the (R) configuration, and are obtained in good enantiomeric excess.A mechanistic rationale is proposed, involving an oxazaborolidine formed from (S)-(+)-prolinol and borane.