Study On Rhodium-catalyzed CH Activation/cyclization To Construct Nitrogen Heterocyclic Compound

N-heterocycles have diverse physicochemical properties,biological activities,and medicinal values.N-heterocycles are the core backbone of many natural products,synthetic drugs and organic functional materials.In recent decade,Rh（Ⅲ）-catalyzed C-H activation/annulation has been rapidly developed as a simple and efficient synthetic strategy for the direct construction of N-heterocycles.Rh（Ⅲ）-catalyzed C-H activation/annulation has the following main advantages:mild reaction conditions,wide source of raw materials,efficient reaction with low catalyst dosage,high atomic economy,no need for additional ligands,good functional group compatibility,and a wide variety of reaction types.In this paper,N-heterocycles such as multifunctionalized isoquinolones derivatives and functionalized 3-alkenylisoquinoline 2-oxides were synthesized based on the reaction strategy of Rh（Ⅲ）-catalyzed C-H activation/annulation.The main contents are divided into three parts as follows:In Chapter 1,we summarized the recent Rh（Ⅲ）-catalyzed C-H activation/annulation reactions for the construction of N-heterocycles,focusing on the annulation reactions involving seven types of compounds such as alkynes,alkenes,diazo compounds,sulfoxonium ylides,anthranils,dioxazolones,and iodonium ylides,and elucidating the subject research of this thesis.In Chapter 2,we have developed a Rh（Ⅲ）-catalyzed one-pot three-component tandem annulation reactions of 2-oxazolines,iodonium ylides,and carboxylic acids.A series of multifunctionalized isoquinolones derivatives were synthesized by Rh（Ⅲ）-catalyzed oxazolines-directed C-H activation and tandem annulation reactions.The tandem reaction has the advantages of readily available starting materials,a wide tolerance of functional groups,a short reaction time,and high yields.The synthetic utility of the tandem reaction strategy was further demonstrated by a gram scale synthesis and derivatization of products.（1）In Chapter 3,we have developed a new strategy to construct 3-alkenylisoquinoline2-oxides from easily available aryl oximes and propargyl alcohols through a Rh（Ⅲ）-catalyzed C-H bond allenylation/annulation reaction.This annulation reaction efficiently and selectively constructed a series of functionalized 3-alkenylisoquinoline 2-oxides using[Cp*Rh Cl₂]₂as the catalyst,aryl oximes as the directing group,propargyl alcohols as the coupling reagent,Cu（OAc）₂as the oxidant and Na OAc as the additive.The annulation reaction has the advantages of mild reaction conditions,readily available starting materials,high atom economy,and good functional group tolerance.