A Simplified Procedure for Aldehyde Enamine Alkylation

Abstract

The elegant C-alkylation method¹ devised by Stork is applicable mainly to ketone enamines; in the cases of aldehyde enamines, predominant quaternization on nitrogen occurs. The latter difficulty has subsequently been circumvented by employing the Grigmard derivatives of imines,² which is reminiscent of the reaction between indolylmagnesium halides and alkyl halides. In the course of an investigation in the steric shielding effect of N-alkyl groups on alkylation, Curphey and Hung³ found that aldehyde enamines derived from n-butylisobutylamine give C-alkylated products in reasonable yields, thereby an operational improvement is attained.