Aryne-mediated Synthesis Of Triaryl Sulfonium Salts

Triaryl sulfonium salts are able to deliver proton under UV conditions and thus they have been widely used as superior photoinitiators in polymerization reactions and lithographic process.Thus,the synthesis of these compounds has received great attention from synthetic community.Traditional approaches include:aryl group transfer from diaryliodonium salts to diaryl sulfides;Friedel Crafts reaction of electron rich arenes with electrophilically activated diaryl sulfoxides;nucleophilic addition of Grignard reagents to diaryl sulfoxides;However the traditional methods are often conducted under harsh conditions with poor selectivity.And some of their substrates are hard to prepare.Therefore,more efficient methods for the synthesis of triaryl sulfonium salts under mild conditions are still highly desired.Based on the benzyne chemistry,the thesis describes two synthetic methods for accessing a number of triaryl sulfonium salts.Inspired by the progress on the reactions of alkyl or mono-aryl thioethers with benzyne,we designed and developed a new method for the synthesis of triaryl sulfonium satls via the nucleophilic addition of diaryl thioethers to benzyene.It was found that the reaction may proceed under mild conditions with excellent selectivity and broad substrate scope which is a practical synthetic methods to access triaryl sulfonium salts.In recent years,the insertion of benzyne into "S=O" bond of sulfoxides has been validated and advanced producing various of aryl thioethers.In contrary to the reported procedures,this thesis use the insertion of benzyne into "S=O" bond,triaryl sulfonium salts were furnished from diaryl sulfoxides and benzyne.It was found that the reaction may proceed under mild conditions with broad substrate scope and excellent selectivity which is complementary to the traditional methods.