Cobalt(I)-Mediated Intramolecular [2+2+2] Cocyclizations of (Methylenecyclopropyl)diynes as an Easy Access to Cyclopropanated Oligocycles
作者:Michael Schelper、Olivier Buisine、Sergei Kozhushkov、Corinne Aubert、Armin de Meijere、Max Malacria
DOI:10.1002/ejoc.200500111
日期:2005.7
Enediynes with methylenecyclopropane moieties attached either through the three-membered ring or the double bond smoothly underwent cobalt-mediated [2+2+2] cocyclizations to give cyclopropane-fused and spirocyclopropanated cobalt-complexed tricyclo[7.3.0.02,6]dodeca-1,6-dienes (1,2,3,3a,4,6,7,8-octahydro-as-indacenes) under relatively mild conditions in yields ranging from 31 to 94 % (6 examples).
带有通过三元环或双键连接的亚甲基环丙烷部分的烯二炔顺利地经历了钴介导的 [2+2+2] 共环化,得到了环丙烷稠合和螺环丙烷化钴络合的三环 [7.3.0.02,6]dodeca-1 ,6-二烯(1,2,3,3a,4,6,7,8-八氢作为茚)在相对温和的条件下,产率范围为 31% 至 94%(6 个实例)。前体炔端的吸电子取代基对于成功的低聚环化是必不可少的。虽然二苯氧基膦基取代的烯二炔以高产率提供了作为两种非对映体混合物的三环 [7.3.0.02,6] 十二-1,6-二烯配合物,但类似的甲氧基羰基取代的前体仅产生一种非对映体。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)