Nazarov reaction of trisubstituted dienones: mechanism involving Wagner-Meerwein shift
作者:Jiro Motoyoshiya、Toshikazu Yazaki、Sadao Hayashi
DOI:10.1021/jo00002a047
日期:1991.1
The Nazarov reactions of trisubstituted alpha,alpha'-dienones were studied. Whereas alpha,beta-dimethyl-beta'-alkyl alpha,alpha'-dienones gave 2,3-dimethyl-4-alkyl-2-cyclopentenones when heated in concentrated sulfuric acid, the reaction of beta,beta-dimethyl-beta'-alkyl alpha,alpha'-dienones afforded 3,4-dimethyl-4-alkyl-2-cyclopentenones as the rearranged products. A mechanistic investigation using two deuterated dienones suggests that the Nazarov reactions of the latter dienones are accompanied by Wagner-Meerwein shifts to form the most stable carbocations.