HIGHLY STEREOSELECTIVE SYNTHESIS OF BETA-LACTAMS BY CONDENSATION OF THE TITANIUM ENOLATE OF A CHIRAL 2-PYRIDYLTHIOESTER WITH CHIRAL IMINES

The reaction of the titanium enolalc of a 2-pyridylthioesler derived from (R)-3-hydroxybutync acid with chiral imines affords 3,3\u2032-anti-3,4-trans configurated \u3b2-lactams in a highly selective fashion. The methodology has been applied to the synthesis of a precursor of the carbapenem antibiotic 1\u3b2-methylthienamycin