A New Synthesis of Podophyllum Lignans by Weitz' Aminium Salt-Induced Free Radical Cycloaddition Reaction of a Doubly Unsaturated Ester.
作者:Yoshiaki ARA、Tetsuya TAKEYA、Seisho TOBINAGA
DOI:10.1248/cpb.43.1977
日期:——
(±)-Isopodophyllotoxin (1e) and related lactones 12, 13, 14 were synthesized by a biomimetic procedure from the doubly unsaturated esters 11a and 11b by means of an oxidative free radical cycloaddition reaction utilizing a stable cation radical salt, Weitz' aminium salt, in one step. (±)-Isopicropodophyllin (1g), the trans-fused lactones, 12, 13, and 16, and the cis-fused lactone 17 were also synthesized from the esters 11c and 11b by the reaction with the same reagent.
(±)-异鬼臼毒素(1e)和相关内酯 12、13、14 是利用稳定的阳离子自由基盐 Weitz 胺盐,通过氧化自由基环加成反应,一步法从双重不饱和酯 11a 和 11b 合成的。(±)-Isopicropodophyllin (1g)、反式融合内酯 12、13 和 16 以及顺式融合内酯 17 也是由酯 11c 和 11b 通过与相同试剂的反应合成的。