Single Electron Oxidation Of Electron-rich Olefins/Intermediates

Olefins are among the most versatile building blocks that can be found in many sectors of chemical science,past and present.Electron-rich olefins which show unique intrinsic reactivity have emerged as important synthons for developing novel synthetic methods.In this thesis,I focus on single electron oxidation of electron-rich olefins or intermediates.(1)2,2,6,6-tetramethyl-N-oxopiperidinium-promoted Diverse Transformation of Vinyl AzidesIn this section,a 2,2,6,6-tetramethyl-N-oxopiperidinium(TEMPO+)-mediated three-component diverse transformation of vinyl azides under metal-free conditions is described.The reaction protocols are operationally simple and conducted at ambient temperature,allowing to access various TEMPO-trapped ketones,amides,and a-alkoxyalkyl azides.Preliminary mechanistic studies indicate that an alkene radical cation-mediated radical-radical cross-coupling C-O bond formation could be involved.(2)Oxycyanation and Cyanofluorination of Vinyl EthersIn this part,we introduce two efficient and mild oxycyanation and cyanofluorination of vinyl ethers with 2,2,6,6-Tetramethyl-N-oxopiperidinium or Selectfluor while TMSCN acts as "CN" source.The mechanistic studies indicated that the formation of an electron donor-acceptor(EDA)complex and subsequent single electron transfer(SET)process might be involved in the reaction.(3)Photo-induced Cobaloxime-catalyzed Heck-type Cyclization of AldehydesIn this part,we report a photo-induced cobaloxime-catalyzed Heck-type cyclization of aldehydes with carbon carbon double bonds.This method is characterized by mild reaction conditions,low-cost catalyst,and broad substrate scope.Furthermore,this convenient method readily accommodates significant structural diversity in the linker,offering a wide range of 5-,6-and 7-membered carbocyclic and heterocyclic ring systems.