Visible Light-mediated Synthesis Of 3-aryloxyindole

The 3-aryloxindoles exist in a wide range of biologically active natural products and a series of pharmaceutically active molecules.Over the past two decades,the direct arylation of oxindoles has emerged as one of the most effective and straightforward strategies for the construction of 3-aryloxindoles.However,most of these arylation methods involve a transition-metal(such as Pd,Ni or Fe)catalyzed cross-coupling,or require the use of activated nitroarenes or arynes as precursors.In this dissertation,our works mainly focus on the development of visible-light-promoted photochemical strategy for the direct arylation of oxindoles with non-activated(hetero)aryl halides under mild,operationally simple,and transition-metal-free conditions.The first part of this dissertation expounds the progress of the synthesis of 3-aryloxindoles by direct a-arylation of oxindoles as well as the history of electron-donor-acceptor(EDA)complexes mediated photochemical transformations.The second part introduce an operationally simple photochemical strategy for the direct arylation of oxindoles with(hetero)aryl halides in the absence of both transition metals and photoredox catalysts.Numerous mechanistic studies revealed that the reaction was triggered by the irradiation of the in-situ formed electron-donor-acceptor complex between the electron-rich oxindole enolates and(hetero)aryl halides through an electron transfer process and a radical chain mechanism,which was operative.This operationally simple approach offers a convenient and powerful synthetic tool for accessing 3-aryloxindole products and shows exceptional functional group tolerance.The utility of this process is highlighted by its efficient synthesis of an array of valuable 3-aryloxindole structures.