Citation: Catholico, N.; Tessari, E.A.; Granja, I.J.A.; de Sousa, M.J.A.; Felix, J.F.; Manarin, F.; Godoi, M.; Rafique, J.; Schneider, R.; Saba, S.; et al. Iron-Borophosphate Glass-Catalyzed Regioselective Hydrothiolation of Alkynes under Green Conditions. Catalysts 2023, 13, 1127. https:// doi.org/10.3390/catal13071127 Academic Editors: Victorio Cadierno and Raffaella Mancuso Received: 23 June 2023 Revised: 18 July 2023 Accepted: 18 July 2023 Published: 20 July 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). catalysts Article Iron-Borophosphate Glass-Catalyzed Regioselective Hydrothiolation of Alkynes under Green Conditions Nicoli Catholico 1 , Eduarda A. Tessari 2 , Isis J. A. Granja 3 , Martinho J. A. de Sousa 4 , Jorlandio F. Felix 5 , Flávia Manarin 2 , Marcelo Godoi 6 , Jamal Rafique 3,4 , Ricardo Schneider 7, * , Sumbal Saba 3, * and Giancarlo V. Botteselle 1, * 1 Department of Chemistry, Midwestern Parana State University-UNICENTRO, Guarapuava 85040-167, PR, Brazil; nicolicatholico@yahoo.com.br 2 Center for Engineering and Exact Sciences, Western Parana State University-UNIOESTE, Toledo 85903-000, PR, Brazil; eduardatessari@hotmail.com (E.A.T.);fgmanarin@gmail.com (F.M.) 3 Instituto de Química IQ, Universidade Federal de Goiás-UFG, Goiania 74690-900, GO, Brazil; isisgranja@gmail.com (I.J.A.G.); jamal.chm@gmail.com or jamal.rafique@ufms.br (J.R.) 4 Institute of Chemistry-INQUI, Federal University of Mato Grosso do Sul-UFMS, Campo Grande 79074-460, MS, Brazil; martinhotinho@hotmail.com 5 Institute of Physics, University of Brasilia-UNB, Brasilia 70910-900, DF, Brazil; jorlandio@unb.br 6 School of Chemistry and Food, Federal University of Rio Grande-FURG, Santo Antanio da Patrulha 95500-000, RS, Brazil; marcelogodoi@furg.br 7 Group of Polymers and Nanostructures, Federal University of Technology Parana-UTFPR, Toledo 85902-490, PR, Brazil * Correspondence: rschneider@utfpr.edu.br (R.S.); sumbalsaba@ufg.br (S.S.); giancarlo@unicentro.br (G.V.B.) Abstract: 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@NaH 2 PO 4 -H 3 BO 3 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. Keywords: iron-borophosphate glass; catalysis; vinyl sulfides; hydrothiolation; green chemistry 1. Introduction Glasses or glass-based materials are known for their stability and the high temper- ature commonly required for their synthesis. While glasses can be made using different approaches, the melting and fast-cooling method is widely used. Phosphates, and to some extent phosphate-based glasses, are a distinct group of materials that can be obtained from simple and eco-friendly raw chemicals. However, they usually have low chemical stability (e.g., high moisture sensitivity). Nevertheless, their ability to dissolve oxides at relatively low temperature overcomes the lability of the phosphate network [1,2]. Not only is the modification of the glass network achieved by addition of modifiers (dissolved ions) but also the reactivity of the glass surface [3]. Using appropriate oxides and/or metallic oxides will produce a glass that can be handled under ordinary conditions with superior catalyst performance. In this context, iron oxide is an abundant and affordable raw chemical that can be used in the synthesis of important classes of molecules, such as organosulfur [4,5] and organoselenium compounds [6,7]. Catalysts 2023, 13, 1127. https://doi.org/10.3390/catal13071127 https://www.mdpi.com/journal/catalysts