methyl 13-<(E)-2-(acetylthio)ethylidene>-1,8-dihydroxyspiro
trideca-4,9-diene-2,6-diyne-11,2'-<1,3>dioxolan>-10-yl carbamate 在
camphor-10-sulfonic acid 作用下,
生成 methyl 13-<(E)-2-(acetylthio)ethylidene>-1,8-dihydroxy-11-oxobicyclo<7.3.1>trideca-4,9-diene-2,6-diyn-10-yl carbamate