Enantioselective cyclocarbonylation of 2-vinylanilines to six-membered ring lactams
                                
                                    
                                        作者:Chune Dong、Howard Alper                                    
                                    
                                        DOI:10.1016/j.tetasy.2003.08.045
                                    
                                    
                                        日期:2004.1
                                    
                                    A catalyst system based on Pd(OAC)(2)/(2S,4S)-(-)-4-diphenylphosphino-2-(diphenylphosphinomethyl)pyrrolidine has been found to effect asymmetric cyclocarbonylation of 2-vinylanilines to enantiomerically enriched six-membered ring lactams in excellent yield. The reaction was effected under an atmosphere of CO (500 psi) and H, (100 psi) in methylene chloride for 48 h; the chiral six-membered ring lactams were isolated in up to 98% yield and 84% ee. The stereoselectivity was influenced by the structure of the substrate and the reaction conditions. The enantiopurity of the lactam was further improved by recrystallization with 99% ee obtained in some cases. (C) 2003 Elsevier Ltd. All rights reserved.