Palladium-Catalyzed Three-Component Tandem Reaction of Thioamides, Arenediazonium Tetrafluoroborates and DABSO: An Efficient Synthesis of Arylsulfonyl 1,3-Benzothiazines

Abstract

A novel and efficient palladium-catalyzed three-component cascade reaction for the synthesis of arylsulfonyl-substituted 1,3-benzothiazines has been developed. This protocol involves the reaction of thioamides, arenediazonium tetrafluoroborates, and DABSO via a tandem SO₂ insertion/cyclization process. The transformation proceeds under mild conditions with broad substrate scope, accommodating various aryl, heteroaryl, and alkyl-substituted thioamides as well as diverse diazonium salts, providing the corresponding sulfonylated benzothiazines in moderate to good yields.