Diastereoselective addition of chlorotitanium enolates of N-acyl thiazolidinethione to activated imines — A novel synthesis of β-lactams

We report a novel methodology for preparing enantiomerically pure β-lactams, starting from nitriles in diastereomeric ratios up to 10:1. The power of the methodology was demonstrated by the efficient synthesis of the cholesterol absorption inhibitor SCH 48462.