The synthesis of angular methyl substituted bicyclic enones via a unique regioselective enamine annulation reaction
作者:W.M.B. Könst、J.G. Witteveen、H. Boelens
DOI:10.1016/0040-4020(76)85022-3
日期:1976.1
Enamines of 2,4,4-trimethylcyclopentanone 5 and of 2,5,5-trimethylcyclohexanone 14 react with methyl vinyl ketone to afford the bicyclic enones 9 and 15 in yields up to 70%. The formation of these products bearing an angular Me group is the result of an anomalous enamine Robinson annulation reaction, due to an alkylation of the enamine in the first step at its most substituted α-position. The effect
2,4,4-三甲基环戊酮5和2,5,5-三甲基环己酮14的烯胺与甲基乙烯基酮反应,得到双环烯酮9和15,产率高达70%。这些带有角Me基的产物的形成是烯胺罗宾逊反应异常的结果,这是由于第一步中烯胺在其最高取代的α-位置上被烷基化。在2,5-二甲基环己酮22,香芹酮19,薄荷酮的烯胺反应中,说明了环烷酮的α-和β'-位取代,其环大小,迈克尔受体(烷基乙烯基酮)的结构的影响。26,二氢香芹酮28和四氢大黄酮32具有甲基和/或乙基乙烯基酮。