摘要：

Two cyclohumulanoids, dl-bicyclohumulenone ( 4) and dl-africanol ( 7 were synthesized through newly developed conformationally selective transannular cyclization of humulene 9,10-epoxide ( 2). The epoxide 2 was converted to a bicyclohumulenediol diacetate 3a in 70% yield by treatment with BF 3·OEt 2-Ac 2O, while treatment of 2 with trimethylsilyl trifluoromethansulfonate gave an africen-10-ol ( 5a and 5b) in 80% yield. The two intermediates 3a and 5a furnished the natural products 4 and 7 in 30 and 8 % yield from 2 respectively.

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