Aryl-aryl bond formation by flash vacuum pyrolysis of benzannulated thiopyrans

The flash vacuum pyrolysis of benzannulated thiopyrans which cause the extrusion of the sulfur atom and aryl-aryl bond formation to yield the ring contracted hydrocarbon product is demonstrated. The thermal extrusion of sulfur from benzannulated thiopyrans is observed to be less demanding energetically than thermal decarbonylation of aromatic ketones.