Synthesis of 1,2-Benzothiazines by a Rhodium-Catalyzed Domino C–H Activation/Cyclization/Elimination Process from S-Aryl Sulfoximines and Pyridotriazoles

A method for the synthesis of a large number of 1,2-benzothiazines bearing pyridyl as well as carbonyl groups is developed from rhodium-catalyzed carbene insertions into aromatic C–H bonds of S-aryl sulfoximines using pyridotriazoles by denitrogenative cyclization followed by the elimination of alcohols. The present method involves the N–H/C–H activation of simple alkyl aryl sulfoximines and has the advantages of a broad substrate scope, high functional group tolerance, and good regioselectivity.