Neutral ionic liquid [hmim]Br as a green reagent and solvent for the mild and efficient dehydration of benzyl alcohols into (E)-arylalkenes under microwave irradiation

A mild and efficient, ionic-liquid-assisted, green protocol for the dehydration of benzyl alcohols into the corresponding (E)-arylalkenes under microwave irradiation has been developed. The method utilizes a neutral and recyclable ionic liquid (1-hexyl-3-methylimidazolium bromide) as a reagent and solvent to cleanly provide a wide range of olefins without the need of harsh and expensive Brønsted/Lewis acids. The method was extended to the efficient conversion of acetylated/benzoylated derivatives of benzyl alcohol into their corresponding (E)-arylalkenes.