The sydnone ring as an ortho-director of lithiation. Dilithiation of 3-phenylsydnone and trapping by electrophiles
                                
                                    
                                        作者:Kenneth Turnbull、Douglas M. Krein                                    
                                    
                                        DOI:10.1016/s0040-4039(97)00015-4
                                    
                                    
                                        日期:1997.2
                                    
                                    Readily available 3-phenylsydnone (3) reacts with n-butyllithium/TMEDA to form the dilithio species 4 which can be trapped with suitable electrophiles. This represents the first use of a mesoionic ring system for directed lithiation. (C) 1997, Elsevier Science Ltd.