Silver(i)-catalyzed sequential hydroamination and Prins type cyclization for the synthesis of fused benzo-δ-sultamsElectronic supplementary information (ESI) available: Experimental details, characterization data, copies of 1H and 13C NMR spectrum of products. CCDC 1834668. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c8ob00918j

An intramolecular annulation strategy has been developed for the synthesis of tetrahydrobenzo[ e ]pyrano[4,3- c ][1,2]thiazine derivatives by means of coupling of aldehydes with 2-(4-hydroxybut-1-yn-1-yl)- N -arylsulfonamides using a catalytic amount of silver hexafluoroantimonate in toluene at 80 °C. This is the first report on the synthesis of fused benzo-δ-sultam derivatives through C-N, C-O, and C-C bond formations. The reaction proceeds through a cascade of hydroamination and Prins type cyclization. An intramolecular annulation strategy has been developed for the synthesis of tetrahydrobenzo[ e ]pyrano[4,3- c ][1,2]thiazine derivatives by means of coupling of aldehydes with 2-(4-hydroxybut-1-yn-1-yl)- N -arylsulfonamides using a catalytic amount of silver hexafluoroantimonate.