A mild and catalytic decarboxylation of α-iminoacids by tributyl phosphine.

alpha-Iminoacids, prepared from a-keto acids and primary amines, undergo decarboxylation to the corresponding imines by reaction with a catalytic amount of tributylphosphine. No reaction has been observed with alpha-keto acids or their phenyl-hydrazone, tosyl-hydrazone or oxime derivatives under the same conditions. However, carboxy-azines react rapidly with tributylphosphine and give the corresponding aldazines quantitatively. The mechanism of this reaction is also discussed. (C) 1998 Elsevier Science Ltd. All rights reserved.