Mechanochemically Initiated Achmatowicz Rearrangement.

The Achmatowicz rearrangement converts furfuryl alcohols, obtainable from renewable carbohydrates, into 6-hydroxy-2H-pyrane-3(6H)-ones, which are versatile intermediates for organic synthesis. We describe here the first examples of a solvent-free mechanochemical Achmatowicz rearrangement. Furfuryl alcohols were prepared from furfurals using mechanochemically initiated reductions and Reformatsky reactions. Mechanochemical reaction conditions for the Achmatowicz rearrangement of the obtained furfuryl alcohols were optimized and applied to a series of derivatives, yielding the corresponding rearrangement products in yields of 39 to 95%. [ABSTRACT FROM AUTHOR]