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.