Regioselective functionalization of N-phthaloyl-substituted amino acid and peptide derivatives

Abstract

The free-radical reactions of a range of amino acid derivatives with N-bromosuccinimide are described. The products and relative rates of these reactions indicate that the α-position of an N-phthaloyl-substituted α-amino acid derivative is much less reactive than that of a corresponding N-acyl amino acid derivative toward hydrogen atom transfer. This is attributed to the proactive effects of acylamino and carboxyl substituents, in contrast to the counteractive effects of phthalimido and carboxyl groups. The reactions exemplify procedures for the regiocontrolled functionalization of amino acid and peptide derivatives. © 1991, American Chemical Society. All rights reserved.