Iron-Borophosphate Glass-Catalyzed Regioselective Hydrothiolation of Alkynes under Green Conditions

Vinyl sulfides are an important class of organic compounds that have relevant synthetic and biological applications. The best-known approach to realize these compounds is the hydrothiolation of alkynes under different conditions using metals, toxic and carcinogenic solvents. The development of new catalysts using materials that are environmentally friendly, low in cost, and easy to handle is highly desirable for this reaction. In this regard, glasses have become an important class of materials, since they can be used as a catalyst for chemical reactions. We prepared and characterized an inexpensive and robust iron-doped borophosphate glass (Fe@NaH2PO4-H3BO3 glass). This eco-friendly material was successfully applied as a catalyst for the hydrothiolation of alkynes under solvent-free conditions, affording the desired vinyl sulfides in good-to-excellent yields, with high stereoselectivity. This method of synthesis is attractive because it enables the reuse of the iron-glass catalyst and the scaling up of reactions.