Study On Difunctionalization Of Alkenes Involving Phosphinoyl And Acyl Radicals

Olefins are an important class of organic compounds with a wide range of industrial and biological sources.Alkenes can undergo diversified transformations owe to they contain unsaturated carbon-carbon double bonds.Among these reactions,the difunctionalization of olefins can introduce different functional groups into the olefin molecules in one pot,which not only increases the complexity of the molecules quickly,but also gives organic compounds more potential or specific application values.Compared with traditional ionic reaction,radical-mediated difunctionalization of olefins has become a very practical method due to mild reaction conditions,high activity and distinctive chemoselectivity.Therefore,the development of novel radical-mediated olefin difunctionalization strategies has important theoretical and practical significance.This dissertation,arounding phosphinoyl and acyl radicals mediated difunctionalization of olefins,realizes the cyanophosphinoylation and dicarbonylation of alkenes via the distal migration of cyano and the co-catalysis of photoredox and NHC(N-heterocyclic carbene).A series of ?-cyanophosphoryl compounds and 1,4-dicarbonyl compounds are synthesized by these novel,efficient and green reactions.The thesis involves the following four parts:Firstly,a brief overview of radical difunctionalization of alkenes is given.Subsequently,the structures and properties of the phosphinoyl radical and acyl radical and the difunctionalization reactions that invove phosphinoyl and acyl radicals are introduced,respectively.Secondly,the cyanophosphinoylation of unsaturated olefins containing gem-dicyano groups with phosphorus oxides has been developed under DTBP and Ag OAc.It should be noted that the driving force of this distal migration process comes from the difference of the stability of carbon radicals.This cyanophosphinoylation reaction of unactivated alkenes based on the cyano group migration strategy provides a new case for the synthesis of phosphoryl substituted1,4/5-dicyano compounds.Thirdly,a three-component coupling reaction of aroyl fluoride,styrene and?-keto acid to realize dicarbonylation of olefins by the co-catalysis of photoredox and NHC has been developed.In this protocol,the oxidizing acylthiazolium intermediate was generated in situ by acyl fluoride and triazolium salt,and this intermediate cooperates with the photocatalysts to finish the catalytic cycle.This regioselective1,2-dicarbonylation can simultaneously install two different acyl groups into olefins so that it can provide a novel method for the synthesis of 1,4-diketones.At last,the summary and prospect are described.