Study On Iodine-catalyzed Directed C-H Alkenylation Of Azaheterocycle N-Oxides With Alkenes

C-H bond activation has been attracting great interest in organic synthesis and pharmaceuticals as the most efficient and straightforward method to build C-X(X = C,N,P,S,O ect)bonds.In the process of the exploration,the N-O group which served as an oxidizing directing group has shown good regioselectivity and high reactivity.Moreover,quinolines,one of the most important class of azaheterocycle,are widely used in pharmaceuticals,functional material and dye.Therefore,direct C-H bond activation by using N-O group as oxidizing directing group can be a novel and convenient protocol to achieve functionalization of quinolines.Styrylquinoline is a useful building block in natural products,functional materials and pharmaceuticals as its unique optical-and biological-activity.The current strategy to synthesis styrylquinoline mainly focus on the transition metal catalysis and microwave.However,these procedures still suffer from requirement of transition metals,stoichiometric amount of oxidants and harsh reaction conditions.Herein,it is necessary to develop a simple and efficient synthesis method.In this thesis,we have developed an efficient and regioselective alkenylation of azaheterocycle N-Oxides with alkenes catalyzed by iodine under metal-and external oxidant-free reaction conditions has been developed(Scheme 1).In this transformation,the substrate scope was successfully extended to low activity alkenes,and the N-O group served as an oxidizing directing group and avoided the use of a metal catalyst.Based on the obtained results and the literatures,a plausible reaction mechanism was proposed as follows(Scheme 2):...