(S)-2-((1S,2S)-1-Benzyloxycarbonyl-2-hydroxy-2-methyl-butylcarbamoyl)-2,5-dihydro-pyrrole-1-carboxylic acid tert-butyl ester 在
氯化亚砜 作用下,
以
二氯甲烷 为溶剂,
以75%的产率得到(4S,5S)-3-((S)-1-tert-Butoxycarbonyl-2,5-dihydro-1H-pyrrole-2-carbonyl)-5-ethyl-5-methyl-2-oxo-2λ
4-[1,2,3]oxathiazolidine-4-carboxylic acid benzyl ester