作者:Jan-E. Bäckvall、Claes Löfström、Seppo K. Juntunen、Matthew Mattson                                    
                                    
                                        DOI:10.1016/s0040-4039(00)91988-9
                                    
                                    
                                        日期:1993.3
                                    
                                    Regioselective cyclopropanation of 2-phenylsulfonyl 1,3-dienes at either double bond was achieved by employing two different reagents. Sulfur ylide 1 resulted in a regiospecific cyclopropanation at the electron deficient double bond whereas an iron carbene, thermally generated from 5a, gave cyclopropanation exclusively at the electron rich double bond.