The Preparation of Cyclic Dithia and Thiaza Compounds by the Reaction of Potassium Carbonate with Heterocumulenes and Alkylene Dibromides or Carbonate Catalyzed by Organostannyl Compounds

Cyclic 1,3-dithia- and 1,3-thiaza-2-ylidene compounds were obtained by the heterogeneous reaction of solid potassium carbonate, a sulfur-containing heterocumulene, such as aryl isothiocyanate, carbon disulfide, or carbonyl sulfide, and alkylene dibromides or ethylene carbonate in the presence of bis(tributylstannyl) compounds. The effect of an organostannyl catalyst on these reactions is discussed.