(4R,5S)-4-(4-tert-Butoxycarbonylamino-butyl)-5-((2S,3R)-2,3-dihydroxy-3-methoxycarbonyl-propyl)-2,2-dimethyl-oxazolidine-3-carboxylic acid tert-butyl ester 、
2,2-二甲氧基丙烷 在
camphor-10-sulfonic acid 作用下,
以
丙酮 为溶剂,
反应 20.0h,
以90%的产率得到(4R,5S)-4-(4-tert-Butoxycarbonylamino-butyl)-5-((4S,5R)-5-methoxycarbonyl-2,2-dimethyl-[1,3]dioxolan-4-ylmethyl)-2,2-dimethyl-oxazolidine-3-carboxylic acid tert-butyl ester