Difunctionalization Of Alkenes Involving Carbon-heteroatom Bond Cleavage

Transition-metal-catalyzed selective carbon-hydrogen bond functionalization is a powerful tool for the construction of C-C bonds and carbon-heteroatom bonds in organic chemistry.Over the past decade,transition-metal-catalyzed direct group or substrate-induced selectively sp²C-H bond and sp³C-H bond activation have made great advances.Moreover,alkenes are widely presented in natural products and chemical products,and play a very important role in organic synthesis as raw materials.There are many methods for the transformations of alkenes,and the alkenes difunctionalization reaction using a free radical strategy represents an efficient way.Due to high reactivity of free radicals,they are widely used in life science,medicine,agronomy,and chemistry.Although it therefore remains a challenging area in the rdical-mediated difunctionalization reaction of alkenes by transition metal catalysis,it will also have academic significance and chemical application prospects.Based on the above reasons,this thesis mainly studies the difunctionalization of alkenes through carbon-heteroatom bond cleavage,which includes the following aspects.?1?Recent advances in the oxidative cleavage of carbon-heteroatom bond and generation of trifluoromethyl radicals for the difunctionalization of alkenes are reviewed.The generation of carbonyl alkyl radicals via cleavage of C-Br bonds for the difunctionalization of alkenes is also described.?2?The1,2-aryltrifluoromethylationofarylalkeneswithsodium trifluoromethylsulfinate and hydrazine using copper as catalyst and TBPB as oxidant has been developed.This highly atom and step-economic reaction is initiated by single electron transfer using peroxide TBPB as radical initiator,followed by addition of a CF₃ radical group and an aryl group across the C=C bond of alkenes in a single step.The reaction provides a facile access to various CF₃-substituted 1,1-diarylalkane derivatives in moderate to good yields with good functional groups compatibility.?3?A new copper-mediated radical 1,2-alkylarylation of styrenes with?-carbonyl alkyl bromides and aryl ether that facilitated by silver catlyst is described.The formation of two new carbon-carbon bonds in a single step is achieved by cleavage of the C?sp³?-Br bonds in?-carbonyl alkyl bromides and activation of the C?sp²?-H bonds in aryl ethers cascades,and provides an efficient access to alkylated aromatic hydrocarbon with broad substrate scope and excellent selectivity.