Study On Selenosulfonylation Based On The Vinylidene Ortho-quinone Methide (VQM) Intermediate

As a kind of compounds with special structure,the study of tetrasubstituted olefins has been paid much attention by researchers.Many methods for the synthesis of tetrasubstituted olefins have been reported,but there are few reports on the synthesis of tetrasubstituted olefins containing sulfone functional groups and phenylselenyl functional groups at the same time.In terms of the reaction mechanism of the synthesis of these compounds,they are mainly divided into two pathways: Based on vinyl radical addition pathway and cation species induction pathway.However,these two methods have some shortcomings,such as the narrow universality of the substrate,the strict reaction conditions,the need to add metal catalysts and the poor stereoselectivity.Therefore,on the basis of previous studies,this paper developed a highly efficient and selective synthesis method of tetra substituted β-(seleno)vinyl sulfones under mild reaction conditions.Based on the previous studies of many reactions involving the vinylidene orthoquinone methide(VQM),and fully considering the characteristics of the high reaction activity of the allene portion of the VQM intermediate,it was found that the intermediate can react with selenesulfonate to form bifunctional tetrasubstituted alkenes.The results show that the catalysts and additives have no effect on the yield of the product.The synthesis of β-(seleno)vinyl sulfone can be carried out by simply mixing selenesulfonylation reagent with o-alkynylnaphthol,which is the precursor of the VQM at room temperature.The method has good stereoselectivity and regioselectivity.E/Z ratio is greater than 99:1.At the same time,the mechanism of the reaction was speculated,and the key of the reaction was the VQM intermediate.In addition,the asymmetric synthesis of β-selenylsulfone alkene axial chiral compounds was successfully realized by adding the Cinchona alkaloid derived squaramide catalyst into the system.In the aspect of application,benzofuran and naphthofuran derivatives were synthesized by further converting the synthesized β-(seleno)vinyl sulfone compounds.This paper provids a novel method for the synthesis of β-(seleno)vinyl sulfone compounds.At the same time,due to the particulaity of product structure,it can be used for the synthesis of naphthofuran derivative and alkene axial chiral compounds,which wides the application of these compounds in organic synthesis and provides a basis for the further study of these compounds.