Palladium-Catalyzedortho-Aroylation of 2-Arylbenzothiazoles and 2-Arylbenzoxazoles with Aldehydes

An efficient protocol for the ortho-aroylation of 2-arylbenzothiazoles and 2-arylbenzoxazoles has been developed using aldehydes as the aroyl source. This Pd-catalyzed substrate-directed sp2-hybridized C–H bond functionalization occurs in the presence of the oxidant tert-butyl hydroperoxide. A variety of functional groups on the 2-arylbenzothiazoles, 2-arylbenzoxazoles, and aldehydes are tolerated under the reaction conditions. Regioselective aroylation at the less hindered ortho position was observed for meta-substituted 2-arylbenzothiazoles.