Study On Transition-Metal-Catalyzed Direct Amination Of Arenes

Directly from simple chemical raw materials, the use of rich C–H functional groupfor chemical conversion, is the goal chemists have long been pursuing. However, due toitself thermodynamics and dynamics stability and the existence of various of different C–Hbonds, bringing great challenge to the selective activation and functionalization of C–Hbond. Application of transition metals in the field of C–H bond activation, making itpossible to solve this problem, related research has also made remarkable achievements.Transition metal catalyzed C–H bond activation epitomise the atom economy, concise steps,environment friendly, and other features, has become one of the most active research fieldsin organic chemistry.Nitrogen-containing compound having the biological activity of natural products andsynthetic compounds is seen everywhere, so the C–N bond formation has been the core ofsynthetic organic chemistry. Based on deep understanding the nature of the aminationreagent, development the basic type of C–N bond formation reactions, especially thedevelopment to meet the requirements of green chemistry and atom economy directly fromC–H bond to C–N bond, is an important research area in the organic synthetic methodology.Aromatic amines and their derivatives are widely used in drugs, pesticides, dyes, andconductive polymers, directly from aryl C(sp~2)–H bond to build the C–N bond aroused wideinterest.Transition metal-catalyzed, directed aromatics C–H bond conversion, is a veryimportant aromatic ortho-C–H bond functionalization method in recent years. At present,this kind of reaction is oriented in coordination of transition metal and ligand, make metaladjacent to C–H, and, in turn, activated to form cyclic intermediate with carbon-metal bond,and functional way. But its almost fixed ortho-activation mode, to a great extent, limits itsapplication. Therefore, the development of a method suitable for "arbitrary" C–H bondconversion of aromatics is the key problem of the reaction.In this paper, utilizting palladium catalyst and N-fluorobenzenesulfonimide (NFSI) asnon-nitrene-based nitrogen source, our group successfully developed an intermolecularortho-and para-C–H amination reaction with high regioselectivity. the novel dearomatizedspiropalladacycle intermediate is the key to the success of the reaction. On the basis, coppercatalyzed C–N formation of simple arenes and saccharins is achieved under mild conditions.These works provided an important reference for the development of transition metalcatalyzed aromatic C–H bond transformation.