Visible-Light-Promoted(Phenylsulfonyl)Methylation And Desulfonylation

The methylation reaction is one of the ubiquitous reactions for the formation of C-C bonds. The importance of methylation in organic synthesis and pharmaceutical industry has drawn much attention of organic chemists. Photocatalytic reaction has become a hot topic in the field of organic synthesis in recent years, with the advantages of mild reaction conditions, highly efficient, environmentally-friendly, and so on. So the research of visible-light-promoted methylation reaction is very important.This dissertation is divided into three parts:In the first chapter, a review is made on the common types of methylation, including the methylation reactions via the non-radical process and the radical process, the transition-metal-catalyzed methylation reactions and photocatalytic methylation reactions.The second chapter introduces a visible-light-promoted radical(phenylsulfonyl)methylation reactions of heteroarenes and N-arylacrylamides starting from bromomethyl phenyl sulfone derivatives. This method provides a mild and efficient access to various(phenylsulfonyl)methylated compounds.The third chapter describes our investigations on the visible-light-promoted desulfonylation. One proposal is the formation of heterocyclic methyl radical using potassium tert-butoxide under photoredox conditions. Another attempt is to utilize electronrich phenyl ring for photoredox chemistry. The electronrich phenyl ring lose a electron via photoredox cycle to cause the hemolysis of C-S bond between the benzene ring and the sulfonyl group. Followed by the release of a molecular of sulfur dioxide, the process would form heterocyclic methyl radical. Unfortunately, none of the proposals afforded desired results to date.