Amidyl Radical Produced By Electrooxidation And Its Application In Construction Of C-N Bonds

The cross dehydrogenative coupling to form new C-heteroatom bonds has emerged as a profound method in organic synthesis due to its step-and atom economy characteristics as well as avoiding the prefunctionlization of substrates.Among various C-heteroatom bonds,C-N bond has been in the central position since C-N bonds are important structural moieties in natural products,pharmaceuticals,agrochemicals and material sciences.As a result,efficient and selective construction of a new C-N bond has always been paid much attention in industrial and academic setting.Alternatively,oxidative radical processes have also been developed for the formation of C(sp~2)-N and C(sp~3)-N bonds.Moreover,the toxicity of residual traces of transition metal in products,from the employed catalysts or oxidants,is highly concerned.Consequently,mild,metal-free and atom economic oxidative C-N bonds formation is highly desirable.In this paper,our work includes the following two parts:1)Electrochemical functionalization of amide N-H bondsUnder the electrochemical oxidation conditions,a method for functionalizing C(sp~3)-N bond by functionalization of N-H bond was established.The protocol was proceeded in an undivided cell under constant current conditions employing simple,cheap and readily available ferrocene(Fc)as the redox catalyst.An intermolecular cross dehydrogenative coupling reaction between an N-alkoxyamide and nucleophile was achieved.Under the optimized conditions we investigated the scope of substrate,the gram-scale experiment proved that the reaction had a certain application value.Cyclic voltammetry and control experiments disclosed that the cross dehydrogenative coupling reaction may proceed via an amidyl radical.2)The Formation and Stability of Amidyl Radical under Electrochemical ConditionsThe amide compound can also be synthesized by constructing C(sp~3)-N bond when using halogen as the electrocatalyst,but the substrate of reaction is not generally suitable from the results.This is because the attachment of different substituent groups to the nitrogen atom in the amide compound affects the stability and reactivity of the amidly radical.Through the cyclic voltammetry test,quantum chemistry calculations and actual experimental results can explore the stable structure of the amide substrate and predict the potential of the amide substrate.