Lewis Acid-Promoted Favorskii-Type Ring Contraction of Some Cyclic α-Bromo Ketones and Their Acetals
作者:Swaraj B. Maiti、S. R. Ray Chaudhuri、Amareshwar Chatterjee
DOI:10.1055/s-1987-28079
日期:——
The α-bromo cycloalkyl aryl ketones 2a-d on heating with zinc chloride in methanol furnished in moderate to good yields the ring-contracted products 3a-d having gem methyl carbomethoxy function. The acetals of the related α-bromo ketones 7a-c, lacking the methyl group on the halogen-bearing carbon atom, afforded in acceptable yields the ring-contracted esters 8a-c when heated in protic solvent. The limitation of the present ring-contraction procedure has been discussed.
加热α-溴环烷基芳基酮2a-d与氯化锌在甲醇中反应,获得了中等到良好的产率的环收缩产物3a-d,具有gem-甲基碳甲氧基功能。相关的α-溴酮7a-c的醇醚,缺乏氯原子邻近的甲基,经过加热在质子溶剂中反应,获得了可接受产率的环收缩酯8a-c。对目前的环收缩反应程序的局限性进行了讨论。