The structure elucidation, biosynthesis, and biological activity of marine carbotricyclic sesquiterpene compounds are reviewed from the pioneering results to the end of 2015. Their total syntheses with a particular emphasis on the first syntheses, enantiomeric versions, and syntheses that led to the revision of structures or stereochemistries are summarized. Overall, 284 tricyclic compounds are classified into fused, bridged, and miscellaneous structures based on 54 different skeletal types. Tricyclic sesquiterpenes constitute an important group of natural products. Their structural diversity and biological activities have generated further interest in the field of drug discovery research, although the exact mechanisms of action of these species are not well known. Furthermore, these tricyclic structures, according to their chemical complexity, are a source of inspiration for chemists in the field of total synthesis for the development of innovative methodologies.

中文翻译：

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海洋来源的三环倍半萜

从开创性的结果到2015年底，对海洋碳三环倍半萜烯化合物的结构阐明，生物合成和生物活性进行了综述。它们的总合成特别着重于第一合成，对映体版本和导致结构修改的合成或立体化学总结。总体而言，根据54种不同的骨骼类型，将284种三环化合物分为稠合，桥连和杂类结构。三环倍半萜烯是重要的天然产物。尽管这些物种的确切作用机理尚不清楚，但它们的结构多样性和生物学活性在药物发现研究领域引起了更多兴趣。此外，根据其化学复杂性，这些三环结构