Conversion of Penta‐Acetyl‐Xylitol to 3‐Acetoxymethylene‐Tetrahydrofuran by a Combined Hetero‐/Homogeneous Tandem Catalyst System

Abstract A tandem catalyst system comprised of trifluoromethanesulfonic (triflic acid, HOTf) or hafnium tetratriflate (Hf(OTf) 4 ) and Ru/C in glacial acetic acid (HOAc) as the solvent at 200 °C and ∼ 7 MPa hydrogen pressure in a batch reactor converts penta‐acetyl‐xylitol ((2 R ,3 R ,4 S )‐pentane‐1,2,3,4,5‐penta‐acetoxy‐pentane) or unprotected xylitol to 3‐acetoxymethylene‐tetrahydrofuran (3‐AMT) in up to 15% yield at full conversion. A comparative analysis by SEM‐EDS and XPS of the fresh commercial Ru/C catalyst versus catalyst reused and recovered after five cycles shows increasing aggregation of ruthenium to larger particles with a concomitant decrease in yield of 3‐AMT to 8%–9% for cycles four and five. 3‐AMT or its hydrolysis product 3‐hydroxymethyl‐tetrahydrofuran (3‐HMT) are valuable synthons for the preparation of agrochemicals, pharmaceuticals, and specialty polyurethanes and polyesters.