Copper-Catalyzed Ortho-Sulfonylation With 5-Chloro-8-Aminoquinoline Group-Directed

In the past decades,transition-metal catalyzed direct functionalization of hydrocarbon bonds has become a powerful strategy for rapid construction of complex organic molecules.It avoids the prefunctionalization of starting materials,and shows good step economy and atomic economy.The introduction of directing groups on the basis of transition metal catalysis can achieve accurate control of carbon hydrogen bond regioselectivity and expand the functional group compatibility.More and more researchers have reported the functionalization of hydrocarbon bonds catalyzed by transition metals assisted by bidentate directing groups.Among them,bidentate directing groups are excellent in the construction of carbon carbon and carbon hetero bonds.Sulfone,as a common functional group structure in organic chemistry,is widely used in medicine,agriculture and materials science because of its good biological activity,moreover,it is also widely used as an important intermediate in organic synthesis because of its unique chemical properties.Therefore,the development of efficient synthesis methods for sulfones and their derivatives have attracted people’s attention.The traditional synthesis methods of sulfones include Friedel-Crafts sulfonation reaction to oxidizing corresponding sulfides or aromatics,there are also catalyzed by transition metals to synthesize sulfone and three component synthesis methods of sulfur dioxide.Although these methods can effectively synthesize sulfones,they have regioselectivity or functional group compatibility problems because of the harsh reaction conditions such as strong acid,strong oxidant and high temperature.It is necessary to develop a simple and efficient synthesis strategy of sulfone.In recent years,with the development of transition metal catalyzed hydrocarbon bond,direct hydrocarbon sulfonation has been reported.The catalysts can not be regenerated in the reaction system,so most of these reactions need equivalent metal catalyst or additional chemical oxidant.Therefore,we want to realize the synthesis of hydrocarbon bond sulfones without additional chemical oxidant.We used cheap and easily available copper as catalyst,benzoic acid as ligand,5-chloro-8-aminoquinoline as a bidentate directing groups,easy to operate sodium sulfite as sulfonic source,and oxygen in the air acts as an oxidant to realize the ortho-sulfonation of aromatic formamides.Through the screening and optimization of a series of reaction conditions,the best reaction conditions were obtained,and then the substrate scope was investigated,the related derivatization experiments and reaction mechanism experiments were carried out,affording good result.Finally,the experimental process and steps were recorded,and the products in the reaction were analyzed and characterized.