Synthesis of 4H-1,3-oxathiin-4-ones by reaction of alpha-diazo-beta-diketone with thiones

A series of 2,2-distibstituted 5,6-diphenyl-4H-1,3-oxathiin-4-ones was synthesised by cycloaddition of thiones with benzoylphenylketene, which was generated by the thermal Wolff rearrangement of 2-diazo-1,3-diphenyl-1,3-propanedione. (C) 2001 John Wiley & Sons, Inc.