A short enantioselective synthesis of (−)-bestatin via l-proline-catalyzed α-amination of an aldehyde

A short and high yielding enantioselective synthesis of (−)-bestatin, a naturally occurring aminopeptidase inhibitor, is described via l-proline-catalyzed asymmetric α-amination of 3-phenylpropionaldehyde as the key reaction. The methodology also involves a Pd-catalyzed intramolecular cyclization of an allylic acetate giving a trans-oxazoline in a highly diastereoselective manner (dr > 14:1).