Study On The Cross-dehydrogenative Coupling Reaction Between Saturated Azaheterocycles And Indole Via Visible-light Photocatalysis

The cross-dehydrogenative coupling reaction(CDC)is a method of constructing new C-C bonds between two substrates by breaking their C-H bonds without requiring pre-functionalization using an oxidant.Therefore,this reaction has the advantages of no pre-functionalization,simple reaction steps,and good atom economy.Especially under the development requirements for green chemistry in the21 st century,the CDC reaction has become increasingly favored by scientists around the world.This paper mainly describes the cross-dehydrogenative coupling reaction between saturated aza-heterocycles and indoles under photocatalysis by a visible-lightdriven oxidative-reductive system.In addition,it achieves asymmetric cross-coupling by introducing a chiral Br(?)nsted acid.The paper includes three parts:Chapter One: Firstly,a brief summary is given on the cross-dehydrogenative coupling reactions under different catalytic modes,which can be mainly divided into three categories: transition metal catalysis,photocatalysis,and electrocatalysis.Finally,the current development status and existing problems of cross-dehydrogenative coupling reactions are summarized.Chapter Two: The research status of two different pathways for the synthesis of saturated cyclic amines is described separately.Based on the importance and medicinal value of natural products containing saturated nitrogen heterocycles and indole,the research significance is determined.In this paper,the cross-dehydrogenative coupling reaction between nitrogen-containing heterocycles and indole was realized through organic photocatalyst designed and synthesized by the research group,which is mild in reaction conditions and has a wide range of substrate applicability.In addition,this paper further achieved the coupling reaction of TMSCN,pyrrole,nitromethane,1-naphthol,3,5-dimethoxyphenol,and 2-(trimethylsilyl)furan with saturated nitrogencontaining heterocycles,which further broadened the application range of this method and provided a good solution for the synthesis or modification of drug molecules related to saturated nitrogen-containing heterocycles.Chapter Three: The asymmetric cross-dehydrogenative coupling reactions are classified according to different catalytic modes,and their research significance is elaborated.Based on the analysis of existing asymmetriccatalytic methods,this paper designs an asymmetric cross-dehydrogenative coupling reaction between nitrogencontaining heterocycles and indole,which combines photoredox catalysis and Br(?)nsted acid catalysis.Using 2-(pyrrolidine-1-yl)pyridine and indole as template substrates,the target product was obtained with 71% yield and 61% ee value through organic photoredox catalysis and chiral phosphoric acid synergistic catalysis.This method also provides reference value for the asymmetric functionalization of other saturated nitrogen-containing heterocycles.