Synthesis of 4-Chalcogenylated Isoxazoles Mediated by PhICl2 and Diorganyl Disulfides/Diselenides

This report described that a series of 4-chalcogenylated isoxazoles were readily synthesized from the one-pot reaction of alkynone Z-O-methyloximes with (dichloroiodo)benzene (PhICl2) and diorganyl disulfides/diselenides under metal-free conditions. The reaction process was enabled by the electrophilic organosulfenyl chloride (RSCl) or selenenyl chloride (RSeCl) species, which were generated in situ from the reaction of PhICl2 and diorganyl disulfides/diselenides. The striking feature of the approach is the in-situ formation of the electrophilic RSCl or RSeCl species, thus markedly decreasing the total usage of electrophiles when compared with the existing methods. This method exhibited a good functional groups tolerance for both alkynone Z-O-methyloximes and diorganyl disulfides/diselenides and the reaction could proceed at room temperature under ambient atmosphere within a short time to afford a series of functionalized isoxazoles in moderate to excellent yields.