Visible-Light-Induced Regioselective Addition Reaction Of Phosphinyl Conjugated Enyne With Organosulfur Reagents

Heteroatom chemistry has always been one of the research hotspots in organic chemistry,and has received extensive attention from chemists.Among them,sulfur-containing compounds have been widely used in agriculture,medicine,materials and other fields due to their unique chemical properties and biological activity.Therefore,the synthesis of sulfur-containing compounds is of great significance in both theoretical research and practical applications.At present,energy issues have become increasingly prominent.Visible light as a pure natural green renewable energy resource,has demonstrated broad application prospects.The development of photocatalytic reactions mediated by visible light has received extensive attention due to its inherent sustainability and green chemical characteristics.In the past ten years,the development of visible light photocatalytic chemistry has been advanced in leaps and bounds.After the pioneering work by Mac Millian et al.in 2008,visible light photocatalytic chemistry involving the single electron transfer(SET)pathway has been widely used in many organic reactions.Compared with traditional redox reactions,photoredox systems usually avoid the use of stoichiometric oxidants,reducing agents and free radical initiators,and in most cases,under mild and easy-to-operate conditions(such as air and room temperature)to make the reaction more efficient and environmentally friendly.Based on this and combining the structure and properties of phosphinyl substituted conjugated enyne compounds,the reaction of conjugated enyne and organosulfur reagents was studied in this article.A series of new compounds containing multiple heteroatoms were synthesized using photocatalytic approach with the concept of green and atom economy.The detailed research of this paper is mainly introduced in the following two aspects:1.Visible light-induced 1,4-oxysulfonylation reaction of phosphinyl substituted enyne.With phosphinyl substituted conjugated enyne and sulfonyl chloride derivatives as substrates and iridium complex as photocatalyst,a series of multi-substituted allene compounds containing phosphinyl and sulfone groups were synthesized with high selectivity under blue light irradiation.This is the first example of the difunctionalization of1,3-enyne by photocatalysis,and we have proved the key role of hydroxyl radicals in the reaction.2.Research on regioselective thioetherification reaction of phosphinyl substituted conjugated enyne.With phosphinyl substituted conjugated enyne and thiophenol as substrates,it was found that the regioselectivity of the thiophenol addition site could be controlled by the solvents used,delivering the desired products of alkenes or alkynes accordingly.Finally,a novel kind of [3]Dendralenes and 1,3-enynes with phosphinyl and thioether substitution were accessed in an atom-economic way.This part of work is the first to construct [3]Dendralenes by photochemical means.