(3S,4aR,4bS,6S,8R,8aR,10aR)-6-Acetoxy-3-((S)-2-hydroxy-1-methoxycarbonyl-ethylcarbamoyl)-4a,8a-dimethyl-1,5-dioxo-dodecahydro-2-oxa-phenanthrene-8-carboxylic acid methyl ester 在
[双(2-甲氧基乙基)胺]三氟化硫 作用下,
以
二氯甲烷 为溶剂,
反应 2.0h,
以74%的产率得到(S)-2-((3S,4aR,4bS,6S,8R,8aR,10aR)-6-Acetoxy-8-methoxycarbonyl-4a,8a-dimethyl-1,5-dioxo-dodecahydro-2-oxa-phenanthren-3-yl)-4,5-dihydro-oxazole-4-carboxylic acid methyl ester