Abstract

N-Blocked-D-glutamic acid diethylesters are gamma-regioselectively amidated in a reaction catalysed by Candida antarctica lipase B, carried out in an anhydrous organic solvent. The ratio of gamma:alpha-monoamides, as a measure of regioselectivity, depends on the N-protecting group present in the substrate. In the examples reported in this work, we have found that gamma:alpha ranges from about 4 (N-group = Cbz) to 35 (N-group = isobutyryl). No diamides were detected. (C) 2000 Elsevier Science Ltd. All rights reserved.