Regioselective Lipase-Catalysed Amidation ofN-BlockedL- andD-Aspartic Acid Diesters

The amidation of N-protected aspartic acid diesters catalysed by Candida antarctica lipase B described in this paper takes place in a regioselective way. It may, if the amino function is protected by a suitable protecting group, be a synthetically useful method for regioselective preparation of both aspartic monoamides. The L derivatives react preferentially through the α-position, while the D series substrates display β-selectivity. Because of the short length of the side chain of aspartic acid, the nature of the protecting group and its interaction with the active site determine not only the reaction rate but also the selectivity and synthetic usefulness of the reaction. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)