To produce a tetrahydrofuran derivative useful as an intermediate for pharmaceuticals from easily available raw materials on an industrial scale at a low cost without using highly toxic expensive reagents by reductively cyclizing a specific derivative using a metallic catalyst in the presence of an acidic substance and water.

The objective derivative of formula II (e.g. 2-hydroxy-4- benzyltetrahydrofuran) is produced by the reductive cyclization of a 4- hydroxybutanonitrile derivative of formula I [R1 to R6 are each H, a (substituted) alkyl, an aryl or an aralkyl] [e.g. (R)-3-benzyl-4- hydroxybutanonitrile] with a metallic catalyst (e.g. Raney nickel) in the presence of an acidic substance (e.g. acetic acid) and water. The reaction is carried out preferably in a solvent such as a water-ethanol mixture in a hydrogen atmosphere at about 10-100°C under a hydrogen pressure of about 1-100kg/m2.