Dichlorination of (Hexadehydro-Diels–Alder Generated) Benzynes and a Protocol for Interrogating the Kinetic Order of Bimolecular Aryne Trapping Reactions
                                
                                    
                                        作者:Dawen Niu、Tao Wang、Brian P. Woods、Thomas R. Hoye                                    
                                    
                                        DOI:10.1021/ol403258c
                                    
                                    
                                        日期:2014.1.3
                                    
                                    The efficient dichlorination of benzynes prepared by the hexadehydro-Diels-Alder (HDDA) reaction is reported. Cycloisomerization of a triyne substrate in the presence of dilithium tetrachlorocuprate is shown to provide dichlorinated products A by capture of the benzyne intermediate. A general strategy for discerning the kinetic order of an external aryne trapping agent is presented. It merely requires measurement of the competition between bimolecular vs unimolecular trapping events (here, dichlorination vs intramolecular Diels-Alder (IMDA) reaction to give A vs B, respectively) as a function of the concentration of the trapping agent.