Studies On The Synthesis Of α-alkynyl Ketones And Iodoenyl Sulfides By Functional Groups Of Enyne

In recent years,the bifunctionalization of unactivated olefin through intramolecular functional group migration has been particularly attractive.It is worth noting that the migration of 1,2-alkynyl radical during the difunctionalization of allyl alcohols provides a new way to obtain functionalized ketones,in which theα-alkynyl ketone product is also an important synthetic intermediate and has potential application value in organic methodology.Vinyl sulfides have attracted much attention as complementary components of carbonyl compounds and michael receptors,which have been used in the synthesis of many functional materials,natural products and synthetic reagents.Among them,β-halogenenyl sulfides,including carbon halide bonds,carbon-carbon double bonds,carbon-sulfur bonds,etc.,are easily modified into various functional olefins and alkynyl sulfides.In this paper,the alkylation reaction of 1,4-enyne-3-ol with trimethylacetaldehyde mediated by free radicals was studied,and a new synthesis method ofα-alkyne-ketone compound was established.The synthesis ofβ-iodoenyl sulfide by the reaction of aryl sulfonyl hydrazide and diphenylacetylene was explored.This paper is divided into three parts:(1)The research status and development trend of the series reaction of transformation of unsaturated hydrocarbons initiated by free radicals were reviewed,mainly including:a.proximal functionalization of unactivated alkenes,b.functional reactions of alkynes,c.functionalization of enols involving group migration.Next,the synthesis methods and research progress of alkenyl sulfides were reviewed.(2)A method was developed to selectively synthesizeα-alkynyl ketones by alkynylation reaction with 1,4-enyne-3-ol as substrate and aliphatic aldehydes as alkyl source.Among them,aliphatic aldehydes are various simple alkylaldehydes.The reaction process underwent decarbonization of aldehydes,3-exo-dig cyclization and 1,2-alkynyl group migration.Two new bonds of C(sp~3)-C(sp~3)and C(sp~3)-C(sp)were formed,and finally the difunctional reaction of 1,4-enyne was realized.The reaction conditions of this method are simple,without catalyst,and the yield is excellent.(3)A new method was developed to synthesize iodoenyl sulfide from diphenylacetylene and aryl sulfonyl hydrazine by oxidation addition reaction.Using Cu I as catalyst,aryl sulfonyl hydrazine reacts with iodine to generate arenesulfenyl iodide,followed by homolysis to generate sulfenyl radical,and then forms alkenyl radical intermediate with diaryl acetylene.Finally,the intermediate is replaced with arenesulfenyl iodide to produce the target product.The reaction has the advantages of simple operation,high stereoselectivity and high functional group adaptability.