OPTICALLY-ACTIVE AMINOALCOHOL PROMOTED ADDITION OF 2-PYRIDYLTHIOESTER BORON ENOLATES TO IMINES - ENANTIOSELECTIVE ONE-POT SYNTHESIS OF BETA-LACTAMS

The enolates derived from 2-pyridylthioesters by treatment with BCl3 . Me(2)S and enantiomerically pure aminoalcohols react with aromatic and heteroaromatic imines to afford beta-lactams in a convenient one-pot procedure and in up to 78% e.e. The aminoalcohol can be employed both as the metal ligand and as the base to generate the enolate. Among several aminoalcohols tested, N-methylephedrine turned our to be the more efficient in terms of stereoselectivity.