Hydrocyanation. Part IX. Synthesis of β-cyano-aldehydes by conjugate hydrocyanation of allylideneamines followed by hydrolysis

Abstract

Conjugate hydrocyanation of αβ-unsaturated aldehydes with diethylaluminium cyanide or with hydrogen cyanide and an alkylaluminium was only successful with a substrate having a sterically hindered formyl group. Attempts to desulphurise β-cyano-thiocarboxylates to β-cyano-aldehydes failed. However, allylideneamines (I) carrying a bulky N-alkyl substituent reacted with hydrogen cyanide–alkylaluminium to give 1,3-dicyanopropylamines (II), which were hydrolysed to β-cyano-aldehydes (III) in good yield. 2-Iminopyrrolidines (IV) were formed as by-products.