Copper-catalyzed Methylenation And Olefination Of Alcohol

As one important kind of the organic compounds,alcohols are ubiquitous in nature,and the synthesis and transformation towards are also diverse.The chemical reactions using alcohols as the reaction precursor have been receiving enough attention from organic chemists.Alcohols can be converted into various organic compounds such as aldehydes,ethers,carboxylic acids,olefins,and esters.There are many methods involving applying transition-metal catalysis,because transition-metal catalysis can achieve chemical reactions that are too difficult to achieve under normal conditions.Morover,these methods can also improve the reaction efficiency.Based on our great interest in the transition-metal catalysis,we combined transition-metal catalysis with the functionalization of alcohols and developed the methylation and olefination of alcohols.This article contains the following two parts:Part I:Copper-catalyzed methylenation of alcoholsThe methylenation of alcohols is achieved by using N-methyl amide as a new methylene reagent under the catalysis of copper catalyst.In this reaction,N-fluorobenzenesulfonamide（NFSI）is used as the oxidant,the N-methyl of the amide is activated by a single-electron transfer（SET）processes under the catalysis of Cu Br₂,then the nucleophilic attack of alcohol to the activated N-methyl to generate the methylenation product of the alcohol.Moreover,this reaction taken advantage of high atom economy,because the final byproduct of this methylene reagent can be recycled in excellent yields and then reused in methylenation reactions upon treated with CH₃I.Part II:Copper-catalyzed olefination of alcoholsDienes was prepared via the three-component coupling reactions of alcohols,di-tert-butyl peroxide（DTBP）and methyl arenes.In this reaction,one C-C bond and two C=C bonds were constructed in a single step.The dehydrogenation of alcohols,C（sp³）-H bond activation of methyl arenes and the scission of DTBP are involved in this transformation.DTBP serves as the oxidant and the acetone donor in this reaction,the sequential three-component couplings of alcohols,DTBP and methyl arenes achieve the olefination of alcohols.