Guaiane sesquiterpenes are an important class of biologically active natural products. Several oxygenated bicyclic but also tricyclic derivatives show unprecedented olfactory activity with great importance in perfumery. Their in vivo syntheses are largely controlled by the intrinsic selectivities of terpene synthases and only a few rearrangements of their hydroazulene skeletons were reported, mostly resulting into terpenoids with decalin motives. Using α-guaiene and bulnesene, complex rearrangements into novel tri and tetracyclic terpenoids are described herein. The cationic rearrangement mechanisms of their formation based on subsequent 1,2-H and alkyl shifts promoted by substoichiometric amounts of ethylaluminum dichloride.

中文翻译：

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愈创木烷倍半萜的新重排

愈创木烷倍半萜是一类重要的具有生物活性的天然产物。几种含氧双环和三环衍生物表现出前所未有的嗅觉活性，在香料工业中具有重要意义。它们的体内合成很大程度上受萜烯合酶的内在选择性控制，并且仅报道了其氢甘菊骨架的少数重排，大部分产生具有十氢化萘基序的萜类化合物。本文描述了使用α-愈创木烯和布黎烯，复杂重排成新型三环和四环萜类化合物。它们形成的阳离子重排机制基于随后的 1,2-H 和由亚化学计量的二氯化乙基铝促进的烷基转移。