We report the asymmetric total synthesis of (+)-blennolide C and (+)-gonytolide C isolated from endophytic fungi. The synthesis involved construction of a spirochromanone with a chiral quaternary carbon by the aldolreaction of o-hydroxyacetophenones and optically active α-oxygenated cyclohexenone, followed by cyclization under acidic conditions. Oxidative cleavage of the alkene moiety of the spirochromanone
Synthesis of Paclitaxel. 1. Synthesis of the ABC Ring of Paclitaxel by SmI<sub>2</sub>-Mediated Cyclization
作者:Keisuke Fukaya、Yuta Tanaka、Ayako C. Sato、Keisuke Kodama、Hirohisa Yamazaki、Takeru Ishimoto、Yasuyoshi Nozaki、Yuki M. Iwaki、Yohei Yuki、Kentaro Umei、Tomoya Sugai、Yu Yamaguchi、Ami Watanabe、Takeshi Oishi、Takaaki Sato、Noritaka Chida
DOI:10.1021/acs.orglett.5b01173
日期:2015.6.5
A convergent synthesis of the ABC ring of antitumor natural product paclitaxel (Taxol) is described. SmI2-mediated reductive cyclization of an allylic benzoate possessing an aldehyde function, synthesized from tri-O-acetyl-D-glucal and 1,3-cyclohexanedione, smoothly afforded the highly strained 6-8-6 tricarbocyclic Structure in 66% yield.
Chiral synthesis of the CD ring unit of paclitaxel from d-glucal
The chiral synthesis of the fully functionalized CD ringunit of paclitaxel 3 is described; the three component coupling reaction of a cyclohexenone derived from D-glucal by way of Ferrier’s carbocyclization with vinyl cuprate and formaldehyde effectively constructed the carbon framework of 3.