The Method Of The Inert Bond Activation And Tranformation

Metal catalysis had been widely used in catalytic chemistry.So far,most of the catalytic activation of inert bonds needs to be achieved under the condition of transition metal catalysis.So,on the premise of good catalytic effect,find other high-performance catalyst has become an inevitable trend,so developing a substitute for traditional precious metals,efficient and cheap catalyst system are numerous chemical workers is to conquer the difficulties.In this paper,we first introduce the study of the sp³C-H bond in heterocyclic compounds using elemental sulfur instead of transition metal catalytic system.And nickel catalyst system for the development of a cheap activated C-CN key new means of fracture,we detailed reaction mechanism of in-depth research,especially to separation and characterization of reactive intermediates,reveals the key scientific problems of the catalytic system.This paper mainly includes two major researches:1.The study on elemental-sulfur-promoted C?sp³?-H activation leading to C=S couplingAnapproachtoaccessbioactivethioamideswasdevelopedbasedon elemental-sulfur-promoted rather than transition metal catalytic systems'C?sp³?-H activation of methyl heteroarenes.In this reaction system,the elemental sulfur is not only used as an oxidant,but also as a free radical initiator to participate in reaction induced reaction process.This transformation could successfully furnish a series of heterocyclic thioamides with excellent yields and it could be conducted on gram scale with good reaction efficiency.Mechanistic studies showed that methyl heteroarenes reacted with dimethylamine released from DMF to form the desired thioamide through elemental-sulfur-promoted C-H activation.2.Study on Nickel-Catalyzed Silylation and Borylation of Aryl CyanidesWe had first demonstrated nickle catalyzed C–CN cleavage to construct C-Si and C-B bond by using nitriles with Bpin-SiEt₃ or B₂pin₂ via oxidative addition.In this transformation,the key to this highly efficient C-CN bond cleavage and to construct arylsilicons and arylborons derivatives depends on the appropriate choice of different ligands and bases in the presence of nickel catalyst.The Ni intermediate acylnickel?II?complexes was synthesised and confirmed the mechanism.The method is easily operated,widely used,high atomic utilization rate,mild reaction conditions and simple synthesis route economy.