Preparation of 2, 3, 4-Trisubstituted Piperidines by a Formal Hetero-Ene Reaction of Amino Acid Derivatives

S Laschat, R Fröhlich, B Wibbeling

Index: Laschat, Sabine; Froehlich, Roland; Wibbeling, Birgit Journal of Organic Chemistry, 1996 , vol. 61, # 8 p. 2829 - 2838

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Citation Number: 26

Abstract

N-Benzyl-or N-tosyl-N-(4-methyl-3-pentenyl) amino aldehyde benzylimines, which are obtained from alanine, leucine, or phenylalanine methyl esters in five steps, can be cyclized diastereoselectively in the presence of Lewis acids to give 3-amino-2, 4-dialkyl-substituted piperidines. The product distribution and diastereoselectivity depends on the type of Lewis acid and nitrogen-protecting group. Benzyl-protected imines give 2-alkyl-3-(benzylamino)- ...