Professor Yang Xiaodong / Professor Zhang Hongbin of Yunnan University have made important progress in the research field of free radical cyclization series reaction to synthesize benzofuran

Recently, Professor Yang Xiaodong / Zhang Hongbin of Yunnan University and Professor Patrick J Walsh of the University of Pennsylvania have made important progress in the research field of free radical cyclization series reaction to synthesize benzofuran This achievement was published in angew Chem Int.ed (DOI: 10.1002 / anie 201812369) under the title of "synthesis of benzofuran derivatives through cascade radiocyclization / intermolecular coupling of 2 ‐ azaallyls" Deng guogang, a doctoral student of Professor Yang Xiaodong's research group, is the first author of the paper In this paper, a new method for the synthesis of benzofuran derivatives is reported for the first time As an important bioactive group, benzofuran structural unit widely exists in natural product molecules and drug molecules It has excellent physiological activities in anti-tumor, anti-virus, anti-bacterial, anti-inflammatory, anti-oxidation and cardiovascular system protection In 2015, 34 clinically approved drugs were benzofuran derivatives, including darifenacin, vilazodone, ramelteon, etc Benzofuran ethylamine is one of the important compounds in benzofuran derivatives It is the synthesis precursor of α 2-adrenergic receptor antagonists It has high affinity for serotonin 5-HT 2 and 5-HT 1A receptors, which has attracted the attention of synthetic chemists However, the previous reported synthesis route is long, low yield, high temperature, using transition metal catalysts / ligands / dangerous reagents (palladium catalyst, nickel catalyst, diazomethane, lithium aluminum hydride, etc.) Therefore, it is an urgent scientific problem to develop a new efficient and convenient method for the synthesis of benzofuran ethylamine In this paper, 2-azaallyl and iodoaryl-allylidene ethers were used as reactants In the reaction system of bis (trimethylsilyl) amino sodium as base and glycol dimethyl ether (DME) as solvent, the free radical cyclization series intermolecular coupling reaction was realized for the first time at room temperature, which was applied to the synthesis of benzofuran ethylamines This method has good universality, and can expand the synthesis of a series of multifunctional (heterocyclic) benzofuran derivatives, which are difficult to be prepared by conventional synthesis methods, and can also expand the synthesis of a series of benzo six or seven membered oxygen heterocyclic derivatives It is worth mentioning that the series reaction does not need transition metal catalysis and ligands, which avoids the difficulty of separation of transition metal impurities in the post-treatment process, reduces the reaction cost and avoids the challenges from sustainability, which will be helpful for the future application of the work in the pharmaceutical field This work was supported by NSFC, the Yangtze River scholars and innovation team development plan of the Ministry of education, Yunling scholars and Donglu scholars support plan.