Synthesis of novel optically pure β-lactams

Several new β-lactams were synthesized as racemates via a Staudinger reaction. The corresponding optically pure compounds were obtained in subsequent biotransformation steps either through baker's yeast reduction or lipase resolution. Their absolute configurations were established. The X-ray crystal structures of three new substituted β-lactams are reported here. These compounds represent key building blocks for a variety of medicinally important molecules, including inhibitors of aspartyl proteases and Taxol® analogues.Key words: optically pure β-lactams, lipase resolutions, baker's yeast reductions, Staudinger reaction.