Microwave- or Microreactor-Assisted Conversion of Furfuryl Alcohols into 4-Hydroxy-2-cyclopentenones

The conversion of a variety of furfuryl alcohols, derived from renewable non edible resources such as bran, into 4-hydroxy-2-cyclopentenones was accomplished using microwave irradiation. In subcritical water (220 degrees C, 15.5 bar) without the need for any catalyst the reaction proceeds approximately two orders of magnitude faster with up to twice the yield compared to methods previously reported that apply conventional heating techniques. For the parent furfuryl alcohol the process could be transferred to a microreactor, allowing the synthesis of 4-hydroxy-2-cyclopentenone in a continuous flow system on multigram scale.