26-hydroxy-25(R)-furost-5-en-3β-ol 3-tert-butyldimethylsilyl ether 在
吡啶 、 tetrabutylammonium tetrafluoroborate 作用下,
以
四氢呋喃 为溶剂,
生成 Acetic acid (R)-4-((2S,4aR,4bS,6aS,6bR,7S,8R,9aS,10aS,10bS)-2-hydroxy-4a,6a,7-trimethyl-2,3,4,4a,4b,5,6,6a,6b,7,8,9a,10,10a,10b,11-hexadecahydro-1H-9-oxa-pentaleno[2,1-a]phenanthren-8-yl)-2-methyl-butyl ester