Thermal [2+2]-Cycloadditions of Diphenylketene with Aryl- and Hetaryl-Substituted Thioketones

The reaction of diphenylketene (1) with aryl-and hetaryl-substituted thioketones (2) gave the corresponding 3,3,4,4-tetraarylthietan-2-ones (3) in good yields.Remarkably, the reactions with bis-hetaryl-substituted thioketones occurred significantly faster compared with those involving the bis-aryl-substituted thioketones.The structure of compound 3c has been established by X-ray crystallography.