Asymmetric Synthesis. 32. A New Access to Enantiomerically Pure (S)-(-)-Pipecolic Acid and 2-or 6-Alkylated Derivatives

JF Berrien, J Royer, HP Husson

文献索引：Berrien, J. -F.; Royer, J.; Husson, H. -P. Journal of Organic Chemistry, 1994 , vol. 59, # 14 p. 3769 - 3774

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被引用次数: 67

摘要

Nucleophilic and mild, basic conditions, such as H202 in DMSO with catalytic K2C03, l4 gave the amide 2 without C-5 epimerization, but further transformation of the amide to the ester with Meerwein salt16 afforded 3 in poor yield (27% from 1). Similarly, hydrolysis of 1 with Na202 to give the carboxylic acid salt, 16 followed by estefication with ethyl bromide, 17 gave 3 in very poor yield (15%). Thus the silica gel method was prefered, even though 3 ...