Alkyl Substituent Effects on Pipecolyl Amide Isomer Equilibrium: Efficient Methodology for Synthesizing Enantiopure 6-Alkylpipecolic Acids and Conformational …

ME Swarbrick, F Gosselin…

Index: Swarbrick, Martin E.; Gosselin, Francis; Lubell, William D. Journal of Organic Chemistry, 1999 , vol. 64, # 6 p. 1993 - 2002

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Citation Number: 54

Abstract

Enantiopure 6-alkylpipecolic acid hydrochlorides 1a-e were synthesized in five steps and 15- 59% overall yields from α-tert-butyl β-methyl N-(PhF) aspartate (3) via an approach featuring selective hydride reduction to the corresponding aspartate β-aldehyde 2, aldol condensations with the enolates of various methyl alkyl ketones, and diastereoselective intramolecular reductive aminations. The influence of the 6-position substituent on the ...