An Efficient Route to Phenylselenoethers in the Presence of Ag2O

An efficient protocol for the preparation of phenylselenoethers from unsaturated alcohols using phenylselenenyl halides at room temperature was developed. The procedure employs phenylselenenyl chloride and bromide, some Δ ⁴- and Δ ⁵-alkenols and Ag₂O, as an additive, to generate the tetrahydropyrans or tetrahydrofurans. This method permits the preparation of cyclic phenylselenoethers in high yields and under extremely mild conditions.