Coupling Reaction Of C(sp~3)-H Bond And C(sp~2)-H Bond Based On CDC Strategy

The most popular reaction strategy for constructing effective C-C bonds in recent decades is the Cross-Dehydrogenative Coupling(CDC)reaction.Conceptually,the reaction achieves the advantages of green,environmental protection,high atomic economy and high step economy.Therefore,we also tried to build a C-C bond based on the CDC reaction strategy,using transition metal catalysis to activate the C(sp~3)-H bond and C(sp~2)-H bond to synthesize benzyl sulfone compounds and dihydroquinolinone compounds.We chose 2-(methylsulfonyl)-1,1'-biphenyl as the basic substrate to activate the methyl C(sp~3)-H bond and the benzene ring C(sp~2)-H bond to achieve the ring closure reaction.Separate yields of 20% and 29% can be obtained in the catalytic systems of palladium acetate and rhodium,respectively,using strong bases to participate in the reaction.Unfortunately,adding some electron-withdrawing or electron-donating groups to the benzene ring that needs to be activated cannot promote the reaction well.In the second study,we designed N-isopropyl-N-phenylpivalamide as a basic substrate,combining the electronic effect of heteroatoms and the multi-reaction site of tert-butyl,by activating the methyl C(sp~3)-H bond and benzene ring C(sp~2)-H bond to achieve ring closure reaction,currently under the catalysis of palladium acetate,acidic system,only 4% of the isolated yield can be obtained.Although the yield of the reaction is not ideal,the work itself has great innovation and significance.We are also constantly researching and eager to break through as soon as possible.