TMPMgCl-Promoted Direct Homocoupling Of Unactivated Electron-Deficient N-Heteroarenes

Symmetrical dimers of electron-deficient N-heteroarenes,such as bipyridines and biquinolines,are an array of considerably important compounds with versatile utilities.The methods to prepare the dimers are mainly dependent on transition-metal-catalyzed procedures.While these methods are very useful to the dimers,some limitations are unavoidable.The large use of transition metals does not satisfy today’s urgent requirement of sustainable development.Therefore,a transition-metal-free direct homocoupling of unactivated N-heteroarenes is desirable.Herein we disclose for the first time that TMPMgCl can effectively promote the direct transition-metal-free homocoupling of unactivated N-heteroarenes.This new procedure represents a cost-effective,environmentally benign and practical method to the dimers of electron-deficient N-heteroarenes with the yield up to 92%.The direct homocoupling of unactivated electron-deficient N-heteroarenes was established for the first time in the promotion of TMPMgCl and TMEDA.The utilization of easily accessible and inexpensive unactivated N-heteroarenes as substrates and charge-free air as the oxidant,gram-scalability,and light-emitting Ir-complex preparation but no use of the expensive and toxic transition-metal,these properties donate this work with environmental friend and practicality.