Highly Stereoselective Synthesis of β-Lactams by Condensation of the Titanium Enolate of a Chiral 2-Pyridylthioester with Chiral Imines.

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