First synthesis of gem-difluorothiiranes from cycloaliphatic thioketones and difluorocarbene

The reaction of sterically crowded cycloaliphatic thioketones with phenyl(t rifluoromethyl)mercury and sodium iodide in boiling benzene yielded gem-dif luorothiiranes in fair yields whereas in the case of aromatic thioketones g em-difluoroalkenes were obtained. The formation of these products is ration alized by an addition of difluorocarbene onto the C,S-double bond, followed by the extrusion of sulfur.