A total synthesis of (±)-tetrahydroligularenolide [(±)-2] is described. 10β-Methyl-5β-tetrahydropyranyloxy-trans-2-decalone (6) was converted in seven steps into 3-methoxycarbonyl-5,10-dimethyl-trans-2-decalone (15), which on alkylation with ethyl α-iodopropionate gave 3-(1-ethoxycarbonylethyl)-3-methoxycarbonyl-5,10-dimethyl-trans-2-decalone (19) and 6-(1-ethoxycarbonylethoxy)-7-methoxycarbonyl-1β,8aβ-dimethyl-1,2,3,4,4a,5,8,8a-trans-octahydronaphthalene (20). Hydrolysis of 19 proceeded with a loss of carbon dioxide to afford (±)-tetrahydroligularenolide [(±)-2].
描述了(±)-四氢利加仑内酯((±)-2)的完全合成。10β-甲基-5β-
四氢吡喃氧基-反式-
2-癸酮(6)通过七步反应转化为3-甲氧羰基-5,10-二甲基-反式-
2-癸酮(15),后者与α-
碘代
丙酸乙酯发生烷基化反应,生成3-(1-乙氧羰基乙基)-3-甲氧羰基-5,10-二甲基-反式-
2-癸酮(19)和6-(1-乙氧羰基乙氧基)-7-甲氧羰基-1β,8aβ-二甲基-1,2,
3,4,4a,5,8,8a-反式-八氢
萘(20)。19的
水解反应伴随着
二氧化碳的释放,生成(±)-四氢利加仑内酯((±)-2)。