Sunlight Induced and Alternative Sc(OTf)3 Catalyzed Remote C−H Halogenation of Indoles

Abstract

AbstractA mild and catalyst‐free sunlight induced protocol for the remote meta bromination of electron‐deficient indoles is described for the first time. Herein, N‐bromosaccharin is activated by sunlight irradiation. Alternately, a synergistic activation model (Sc(OTf)3/HFIP) has also been developed for the activation of haloniums, complementary to the light induced strategy. In addition, the cascade C6‐H bromination and benzylic C−H oxidation under photocatalytic conditions was also discussed. High regio‐and chem‐selectivity, mild reaction conditions, and scalability demonstrate great potential of the developed methods in practical applications and further functionalization.