Photocatalytic Cross-Dehydrogenative Amination Reactions between Phenols and Diarylamines

Abstract

The direct intermolecular aryl C–N coupling reaction from precursors without preactivated C–H and N–H bonds has been challenging. Herein, an oxidative system combining a catalytic amount of organic photocatalyst with stoichiometric amount of persulfate was developed to enable the successful cross-dehydrogenative-coupling amination between phenols and acyclic diarylamines in a nonmetallic method. This protocol precludes both coupling partners from prefunctionalization and achieved single regioselectivity of amination products under genuinely simple and benign conditions. Broad scopes of substrates were evaluated with moderate to high efficacy, and the reaction efficiency of electron-deficient phenothiazine and phenol was highly improved. A radical/radical cross-coupling pathway was proposed based on mechanistic studies, wherein a radical chain propagation process was involved.