Photochemical, Thermal, and Base-Induced Access to Hydroazulene Derivatives via Two-Carbon Ring-Enlargement Reactions of Condensed Electrophilic Cyclobutenes
作者:Gaëtan L. Mislin、Michel Miesch
DOI:10.1021/jo025913l
日期:2003.1.1
Enamines, silyl enol ethers, and beta-keto ester anions derived from bicyclo[3.3.0]octan-2-one efficiently underwent a formal [2 + 2] cycloaddition reaction with DMAD and ethyl propynoate leading to a large variety of electrophilic cyclobutenes. The latter were transformed into polyfunctionalized bicyclo[5.3.0]decane (or hydroazulene) ring systems in high yields by fragmentation of the cyclobutene
衍生自双环[3.3.0] octan-2-one的烯胺,甲硅烷基烯醇醚和β-酮酯阴离子与DMAD和丙酸乙酯进行了正式的[2 + 2]环加成反应,从而形成了多种亲电性环丁烯。通过环丁烯部分的断裂,后者以高收率转化成多官能化的双环[5.3.0]癸烷(或氢杂氮烯)环系统。这些两个碳原子的扩环反应被用作合成工具,用于构建代表丁二酚三环骨架的潜在前体的多官能化氢azulene衍生物。