Synthesis of indole-annulated sulfur heterocycles using copper-catalysed C–N coupling and palladium-catalysed direct arylation

A simple and efficient method for the synthesis of biologically relevant 5H-benzo[4,5][1,3] thiazino[3,2-a] indoles and 5,7-dihydroisothiochromeno[3,4-b] indoles has been developed via intramolecular copper catalysed Ullmann-type C-N coupling and palladium catalysed direct arylation from the corresponding precursors 2-(2-bromobenzylthio)-1H-indole and 2-(2-bromobenzylthio)-1-methyl-1H-indole, respectively, in good to excellent yields.