Enantioselective Synthesis of (R)- and (S)-α-Alkylcysteines via Phase-Transfer Catalytic Alkylation
摘要:
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.