Easy Access to (<i>n</i>+3)-Dimethylamino-1-ethenylbicyclo[<i>n</i>.1.0]alkanes and their Facile Conversion to Ring-annelated Cyclopentadienes
作者:Armin de Meijere、Tobias Voigt、Harald Winsel
DOI:10.1055/s-2002-32971
日期:——
Compounds 7b-d could be transformed by thermal vinylcyclopropane to cyclopentene rearrangement to the corresponding exo-4-dimethylaminobicyclo[n.3.0]alk-l-enes 7b-d (84-90%). Elimination of the dimethylamino group led to the cyclopentadienes 11b-d and 12b-d (72-82%). The 5-dimethylamino-1-ethenylbicyclo[2.1.0]pentane did not undergo the typical vinylcyclopropane rearrangement, but ring-opening at the bridgehead-bridgehead
1-乙烯基环烯烃 2a-d 与 N,N-二苄基-和 N,N-二甲基甲酰胺的氨基环丙烷化反应,分别在甲基三异丙醇钛存在下用环己基溴化镁处理,得到外型-(n+3)-N,N-二甲氨基-1-乙烯基双环[n.1.0]烷烃3a-d (58-72%)。化合物 7b-d 可以通过热乙烯基环丙烷转化为环戊烯重排为相应的外型 4-二甲氨基双环 [n.3.0] 烷烃 7b-d(84-90%)。消除二甲氨基得到环戊二烯 11b-d 和 12b-d (72-82%)。5-二甲氨基-1-乙烯基双环[2.1.0]戊烷没有经历典型的乙烯基环丙烷重排,而是在桥头-桥头键处开环形成1-乙烯基-2-二甲氨基环戊烯8。