Iodination/Sulfonylation,and Radical Cyclization Of 1,2-diarylethynes

Polysubstituted olefins and heterocyclic compounds are ubiquitous in natural products and artificially synthesized functionalized molecules.They also have a wide range of applications in the field of organic chemistry.Hence,rapidly and efficiently constructing these two types of compounds is one of the major areas in the research of organic synthesis chemistry,which has drawed the attention of scientists for decades.Although many related synthetic methods have been reported,new synthetic methods are still emerging.The 1,2-difunctionalization and cyclization of alkynes exhibits remarkable advantages in construction of polysubstituted olefins and indole compounds,which features simple steps and high utilization of atom.This article focuses on the construction of skeletal molecules with potential pharmaceutical or material application value based on the 1,2-difunctionalization and cyclization of alkyne.The main contents are as follows:In the first chapter,we briefly introduced the recent research progress of 1,2-difunctionalization reactions and other functionalized cyclization reactions involved in alkynes.The second chapter described the iodination and sulfonylation of 1,2-diarylethynes under the combination of tert-Butyl hydroperoxide and iodine.In this process,sulfonyl hydrazine was denitrogenated to give a sulfonyl radical which experiences selective addition of 1,2-diarylethynes subsequently.Finally,the iodine radical coupled with an alkenyl radical to obtain a tetrasubstituted olefin.This method provided a new strategy for construction of tetra-substituted olefins,rapidly and efficiently.In the third chapter,we reported a Cu(II)and tert-Butyl peroxybenzoate co-catalyzed synthesis of indole derivatives from 2-alkynylarylazides and 2-alkynylaryl azide with mild reaction conditions and good functional group compatibility.Based on literature and control experiments,We believed that Cu(II)could catalyze the denitrogenation of sulfonylhydrazone compounds to gain sulfonyl radicals under mild conditions.Then,the radical was captured by diarylethynes,followed by a 5-endo-dig cyclization reaction and HAT(hydrogen atom transfer)from the surrounding environment to give the indole compound.