Investigation Of Visible-Light-Mediated Benzylic Sp~3 C-H Functionalization Reaction

Benzyl bromide derivatives are important organic intermediates in pharmaceutical and agrochemical synthesis. Benzyl bromides have wide applications in organic synthesis. They usually serve as the precursors to carbanions, carbon radicals, carbocations, and organo–transition-metal species. Thus, the introduction of bromine atom into organic molecules is of great importance. We successfully achieved functionalization of unactivited benzylic sp~3 C-H bonds to C-Br bonds via photoredox catalysis. The product could be further converted to benzyl amine derivatives. A ring-opening reaction of cyclic acetal and oxazolidine derivatives were also achieved by the same strategy.This thesis is divided into three parts:The first chapter is a mini review of recently reported visible-light-catalyzed functionalization of N-a-sp~3 C-H bonds, O-a-ap3 C-H bonds, and unactivited benzylic C-H bonds.The second chapter is about visible-light-promoted functionalization of unactivated benzylic sp~3 C-H bonds. Ethylbenzene derivatives were converted to the corresponding benzyl bromides or afforded benzyl amine derivatives in a one-pot manner under photoredox conditions. This new reaction is a rare C-H amination strategy via C-H activation/C-X formationThe third chapter is about visible-light-promoted ring-opening reaction of acetals and 2-phenyloxazolidines via benzyl bromide intermediates.