作者:Masaru Hashimoto、Hiroko Harigaya、Mitsutoshi Yanagiya、Haruhisa Shirahama
DOI:10.1021/jo00007a013
日期:1991.3
The first total synthesis of the triterpene ether teurilene (1) has been accomplished utilizing two vanadium(V)-catalyzed oxidation-cyclization reactions with different stereoselectivities. The synthesis involved stereoselective and step-by-step construction of 2,5-cis- and 2,5-trans-tetrahydrofuran rings, vanadium(V)-catalyzed oxidation of 4-substituted 4-en-1-ol 40 and subsequent cyclization of the resulting anti-epoxy alcohol 41, and a similar oxidation-cyclization of 5-substituted 4-en-1-ol 49 by way of syn-epoxy alcohol 50. This was followed by construction of a third tetrahydrofuran ring by more conventional means. An improved synthesis of 1, which featured direct formation of bis(tetrahydrofuran) 51 from squalene derivative 66 by simultaneous double oxidation-cyclization, was also accomplished.