Syntheses of Unsymmetric (Sulfoxylidene)ureas from NH-Sulfoximines and Dioxazolones Assisted by 2,2,2-Trifluoroethanol

Ureas and sulfoximines are relevant as natural products and pharmaceuticals. The fusion of these two frameworks results in (sulfoxylidene)ureas. Herein, we present a convenient method to access such compounds from NH-sulfoximines and dioxazolones. The reactions are assisted by 2,2,2-trifluoroethanol (TFE), yielding the desired products in moderate to good yields under mild reaction conditions. The process, which involves a Curtius rearrangement, is characterized by its simplicity and the absence of any additional activator rendering it appealing for applications in medicinal chemistry.