A general, straightforward and odourless ring-opening reaction allows the preparation of β-hydroxy sulfides from in situ generated S-alkylisothiouronium salts in urea–choline chloride-based deep eutectic solvent (DES). In addition, reaction of epoxides with thiourea in DES yields the corresponding thiiranes.
Key words
deep eutectic solvent - epoxide - odourless thiol chemistry