Study On Bifunctional Properties Of Olefins And Alkynes

The difunctionalization of alkenes and alkynes is a simple and powerful strategy for the synthesis of various organic compounds with the advantages of low cost and high atom economy.Over the past few decades, the difunctionalizations of alkynes and alkynes have gained much attention of organic chemists. Various important natural products, drug molecules and fine chemical products have been effective synthesized through the direct functionalization of olefins and alkynes. Based on the previous works in this area, the difunctionalization reactions of alkenes and alkynes have been further explored, hoping to supplement the current research in the field.This dissertation is made up of four chapters:(1) A metal-free and cost-effective synthesis protocol has been initially proposed for the construction of CF3-containing oxindoles via the direct oxidative trifluoromethylation of activated alkenes with Langlois’ reagent(CF3SO2Na). The present methodology, which utilizes very cheap CF3 reagent and a simple oxidant, provides a convenient and practical approach to CF3-containing oxindoles with a wide variety of functional groups.(2) A novel, simple, and cost-effective copper-catalyzed direct cyanoalkylarylation of activated alkenes with AIBN has been developed with cheap K2S2O8 as the oxidant. A series of cyano-containing oxindoles that are otherwise difficult to obtain through previous methods were efficiently synthesized using this protocol.(3) A novel and metal-free procedure has been developed for the construction of3-sulfonated coumarins via the direct difunctionalization of alkynoates with sulfonylhydrazides.The present protocol, which simply utilizes TBAI as the catalyst and TBHP as the oxidant,provides a convenient and highly efficient approach to construct a series of sulfonated coumarins with high regioselectivity and good functional group tolerance.(4) A novel direct oxidative spirocyclization of arylpropiolamides with sulfonylhydrazides leading to 3-sulfonated azaspiro[4,5]trienones has been developed under metal-free conditions.This reaction is performed in a tandem manner constituted by the sequential sulfonylation of alkynes, ipso-carbocylation, dearomatization, hydration, and oxidation processes, which provides a convenient and efficient approach to various biologically important sulfonated azaspiro [4,5]trienones.