A synthesis of γ-alkylidenebutenolides photochemical rearrangement of 2,3-epoxy-1,4-cyclohexanediones
作者:Tohru Kitamura、Yosihide Kawakami、Takeshi Imagawa、Mituyosi Kawanisi
DOI:10.1016/0040-4020(80)87016-5
日期:1980.1
Photo-induced rearrangement of 2,3-epoxy-1,4-cyclohexanediones was investigated for a synthesis of γ-alkylidene-γ-butyrolactones and γ-alkylidenebutenolides. Irradiation of epoxy diketones 1 and 4 in acetone gave γ-lactones, 2 and 5, and triketones, 3 and 6. On the other hand, in CH2Cl2, EtOAc, or PhH solution epoxy diketones 1 and 4 gave only triketones, 3 and 6. Retro-Diels-Alder reaction of γ-lactones
研究了2,3-环氧-1,4-环己二酮的光诱导重排,以合成γ-亚烷基-γ-丁内酯和γ-亚烷基丁烯内酯。在丙酮中辐照环氧二酮1和4得到γ-内酯2和5,三酮3和6。另一方面,在CH 2 Cl 2,EtOAc或PhH溶液中,环氧二酮1和4仅生成三酮3和6。γ-内酯5aE或5aZ在230°(20 mmHg)下的Retro-Diels-Alder反应得到γ-亚烷基烯丁内酯除蒽外,还包括7aE和7aZ。根据该程序,制备了丁烯内酯7bZ,其是合成freelingyne的关键中间体。还讨论了光化学重排中的显着溶剂效应。