Study On Visible-light Induced 1,7-Enyne Bicyclizations For The Synthesis Of Dihydrofuran Quinolinone

Since the structure of 1,7-enyne compounds has both carbon-carbon double bonds and carbon-carbon triple bonds,this structure can be used to realize tandem cyclization reaction to achieve the preparation of complex cyclized structure compounds.Therefore,1,7-enyne compounds are also considered as important precursors for the synthesis of compounds with complex cyclic structures.Dihydrofuran quinolinone,as an important fused ring compound,is widely found in nature,especially in many plants with natural medicinal properties.At the same time,it also shows significant pharmacological and biological activities,such as anti-virus,anti-inflammatory and antibacterial.So far,researchers have developed a variety of methods for the preparation of furan quinolinone compounds.But for the development of a simple,low-pollution synthetic strategy also need to increase research efforts.The synthesis of dihydrofuraquinolinone was studied.With 1,7-enyne as the reaction substrate,ethyl bromodifluoroacetate produced ethyl difluoroacetate free radical via visible light photoredox catalyst,and 1,7-enyne reacted with this free radical to realize the synthesis of dihydrofuraquinolinone.Therefore,13 different substituted 1,7-enynes were synthesized in this experiment,and the reaction of 1,7-enyne with ethyl bromodifluoroacetate was induced by visible light.A variety of dihydrofuranquinolinone compounds substituted by ethyl difluoroacetate were synthesized in medium yield,which proved that the reaction has certain universality.In addition,the reaction conditions were optimized and the best reaction conditions were determined.Finally,the possible mechanism of this reaction was proposed based on the previous reported literature and free radical capture experiments.