Studies On The Photoinduced Cycloaddition Reactions Of 2-chloroindole-3-aldehydes And 3-acetyl-2-chloroindoles With Styrenes

The dehalogenation of the halogenated compounds by photosensitized and photoinduced electron transfer reactions is an important method to produce the free radicals,and has been widely used in the synthesis of substituted arenes and various polycyclic compounds.This thesis mainly deals with studies on the photoinduced cycloaddition reactions of 2-chloroindole-3-aldehydes and 3-acetyl-2-chloroindoles with styrenes.It consists of two parts:The first part is an introduction of the photoinduced electron transfer reactions and their application in organic synthesis,and the review of photochemical dehalogenation reactions,including the photoinduced coupling,substitution,addition and cyclization reactions,particularly photochemical reactions of halogenated heterocyclic compounds in recent years.The second part is the examination in detail the photoinduced cycloaddition reactions of 2-chlorindoles(1a-1f) with electron-rich olefins such as styrene(2a), ct-methyistyrene(2b),1,1-diphenylethene(2c) and anethole(2d) in acetone in the presence of pyridine.A novel and efficient procedure for the synthesis of alkyl-substituted benzo[c]carbazoles has been achieved via photodechlorination-initiated coupling reactions,electrocyclic reactions and deformylative aromatization.