2016 年 64 巻 10 号 p. 1492-1498
From the stems of Croton cascarilloides, further crotofolane-type diterpenoids, named crotocascarins L–Q (1–6), and a rearranged one (7), named neocrotocascarin were isolated. Their structures were elucidated from spectroscopic evidence. Also, the structures of crotocascarin O (4) and neocrotocascarin (7) were determined by X-ray crystallographic analyses. As a result, neocrotocascarin (7) was found to possess a new carbon framework. A plausible mechanism for the formation of neocrotocascarin (7) is also discussed.