Oxiranes react smoothly with thiourea in the presence of β-cyclodextrin in water at room temperature under neutral conditions to afford the corresponding thiiranes in excellent yields; the β-cyclodextrin can be recycled.
A simple and efficient method for the conversion of oxiranes to thiiranes using ammonium thiocyanate (NH4SCN) under solvent- and catalyst-free conditions is described. These conditions enable clean and fast conversion of oxiranes to the corresponding thiirane.