Copper-Catalyzed Oxidative Coupling Of AIBN With Ketone-Derived Enoxysilanes

Transition metal catalyzed cross-coupling reactions are one of the most significant reactions in the field of organometallic chemistry,which has attracted much attention of more and more researchers.Such reactions are commonly used to construct C-C bonds,C-N bonds,C-O bonds,C-S bonds,etc.The methods of efficiently and directly constructing various chemical bonds by cross-coupling reactions are of great significance for the development of organic synthesis,drug synthesis,and polymer materials.With the rapid discovery of oxidative cross-coupling reactions,various free radical cross-coupling reactions also have been continuously developed.Nevertheless,as emerging reactions in recent decades,the development of cross-coupling reactions still confront challenges to some extent.For example,the range of applicability of substrates is limited.What’s more,most of the transition-metal catalysts are normally very expensive,most coupling reactions inevitably using precious metal catalysts and the atomic transformation number(TON)of non-metallic catalytic systems are limited,etc.Therefore,finding a milder and greener method to construct new chemical bonds will be the main development direction of cross-coupling reactions.In this paper,the development of cross-coupling reactions is reviewed firstly,and the development history of the first generation cross-coupling reactions to the fourth generation oxidative coupling reactions is highlighted.In addition,cross-coupling reactions involving various free radicals are introduced from three aspects:the addition of free radicals,the cyclization of free radicals and the coupling of free radicals and free radicals.Subsequently,the second chapter of this paper introduces a novel copper-catalyzed free radical oxidative coupling reactions to synthesize various y-ketonitriles.In this reaction system,redox active copper plays a dual role:on the one hand,it reduces the energy of free radical SOMO orbital and activates free radicals through coordination;on the other hand,it acts as an electron bridge to accelerate the electron transfer between the free radical and the nucleophile.In addition,the inert and low-toxic AIBN is no longer a free radical initiator,but generates an alkyl nitrile free radicals to directly participate in the reaction.A series of functionalized derivatives of y-ketonitriles have been obtained by using simple and ketone-derived enoxysilanes as the nucleophilic reagents,Ag2CO3 as an oxidant,inexpensive and readily available copper as the transition metal catalyst at 100 ℃ for 12 hours.