Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8601, Japan.
Org Lett. 2021 Feb 5;23(3):989-994. doi: 10.1021/acs.orglett.0c04198. Epub 2021 Jan 14.
Physalins are a structurally complex family of 13,14-secosteroids isolated from the genus . We disclose a two-step construction of the CDE ring moiety of the physalins from a steroidal compound bearing 14-OH, 18-COOMe, and 17, 20-α-epoxide based on our biosynthetic proposal. C13-C14 bond cleavage by an alkoxy radical at C-14 and spontaneous epoxide ring opening gave a compound having a cyclononene and γ-lactone. Diastereoselective dihydroxylation of the resulting alkene with OsO provided the CDE ring moiety of physalin.
豆荚，从属于 属的 13,14- 甾体中分离出的一种结构复杂的 13,14- 甾体家族。根据我们的生物合成假说，我们披露了一种从带有 14-OH、18-COOMe 和 17、20-α-环氧化物的甾体化合物构建 physalins 的 CDE 环部分的两步法。C-14 位上的烷氧基自由基引发的 C13-C14 键断裂和自发环氧化物开环生成了具有环壬烯和γ-内酯的化合物。用 OsO 对生成的烯烃进行立体选择性二羟基化反应，得到 physalin 的 CDE 环部分。
