The fluorenone imines of glycine esters and their phosphonic acid analogues

Abstract

(Chemical Equation Presented) Much more reactive than the corresponding benzophenone imines, which have often been used in the synthesis of α-amino acids, the title compounds undergo Mannich-type reactions with imines in the presence of a catalytic amount of a base to afford α,β-diamino acid and α,β-diaminophosphonic acid derivatives with high syn diastereoselectivity (see scheme). An asymmetric version of the reaction is also described. Boc = tert-butoxycarbonyl. © 2008 Wiley-VCH Verlag GmbH & Co. KGaA.