Synthesis of Dibenzothiazines via a Palladium Catalyzed Cyclization of Aromatic Sulfoximines with Benzynes

Abstract

Aromatic heterocyclic rings are the backbone of various natural products and biologically active compounds. And, these compounds are made up of carbon-carbon or carbon-heteroatom bonds. Transition metal catalysed reactions are one of the efficient ways to construct these bonds. Annulation via chelation-assisted C-H bond activation is a most effective pathway in the synthesis of heterocyclic compounds since the synthesis of tri-heterocyclic rings is still limited in the literature. Here we reported the formation of a tri-heterocyclic ring, dibenzothiazines through the cyclisation of phenyl sulfoximine into benzyne ring in the presence of Palladium acetate, potassium persulfate and Pivalic acid at 110-degree celius.