Journal of Organic Chemistry 2006-10-13

Enantioselective synthesis of (R)- and (S)-alpha-alkylcysteines via phase-transfer catalytic alkylation.

Taek-Soo Kim, Yeon-Ju Lee, Byeong-Seon Jeong, Hyeung-geun Park, Sang-sup Jew

Index: J. Org. Chem. 71 , 8276, (2006)

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Abstract

We reported efficient enantioselective synthetic methodologies for (R)-alpha-alkylcysteines and (S)-alpha-alkylcysteines. The phase-transfer catalytic alkylation of 2-phenyl-2-thiazoline-4-carboxylic acid tert-butyl ester and 2-o-biphenyl-2-thiazoline-4-carboxylic acid tert-butyl ester, in the presence of chiral catalysts (1 or 2), gave the corresponding alkylated products, which could be hydrolyzed to provide (R)-alpha-alkylcysteines (67->99% ee) and (S)-alpha-alkylcysteines (66-88% ee), respectively.