Synthesis of 2‑Arylimino-6,7-dihydrobenzo[d][1,3]oxathiol-4(5H)‑ones via Rh2(OAc)4‑Catalyzed Reactions of Cyclic 2‑Diazo-1,3-diketones with Aryl Isothiocyanates

A convenient and efficient synthesis of 2-arylimino-6,7-dihydrobenzo­[d]­[1,3]­oxathiol-4­(5H)-ones was developed via a Rh2(OAc)4-catalyzed reaction of cyclic 2-diazo-1,3-diketones and aryl isothiocyanates in acetone at 60 °C. This reaction uses readily available stable cyclic 2-diazo-1,3-diketones as a starting material and generates the desired products in good to excellent yields (78–93%). The reaction proceeds under mild reaction conditions, produces only N2 as the byproduct, and features a broad substrate scope. A plausible mechanism for this reaction is also discussed.