Synthesis Of Heterocycles Via1,2-difunctionalization Of Alkynes And Alkenes

The hetrocycles, as the key skeleton of many natural products and drugmolecules, have been widely applied in many fields of materials, life science andothers. Although a numbers of methods for construction of hetrocycles viadifunctionalization of alkynes or alkenes have been established, the development ofsynthetic methods, environment-friendly, high selectivity, more efficient and easyoperation will be more significant. The thesis mainly focuses on the1,2-difunctionalization of alkynes or alkenes and includes the following three parts.(1) The direct oxidative cyanoalkylation of alkenes with azobisisobutyronitrile(AIBN) proceeded smoothly via N–N bond cleavage for the preparation ofcyanoalkyl-containing oxindoles has been developed in the presence of CuCl anddi-tert-butyl peroxide (DTBP) in good yields. The approach is efficient, easyoperation and high atom-economy.(2) A series of3-sulfonated coumarins were synthesized by visible-light inducedEosin Y catalyzed difunctionalization of alkynes with sulfinic acids via C–C and C–Sbond formation at room temperature under metalfree conditions. Compared to theprevious strategys, this approach realized the first Eosin Y-catalyzed arylsulfonylationof alkynes with arylsulfinic acids by visible-light initiation, which provided a novelapproach to the construction of coumarin backbone.(3) A numbers of1,2,3-triazoles were prepared from the cycloaddition reactionsof chalcones with azides promoted by base under metal-free conditions. Comparedwith the reported methods, the transformation did not need any transition-metal,oxidants, additives.