Abstract: The invention relates to a process for the preparation of (4-hydroxy-6-oxo-tetrahydro-pyran-2-yl)-acetonitrile from 6-X-substituted-methyl-4-hydroxy-tetrahydro-pyran-2-one, wherein X stands for a leaving group, by reacting 6-X-substituted-methyl-4-hydroxy-tetrahydro-pyran-2-one with a cyanide ion in water and by subsequent lowering of the pH to a pH between 0 and 5. (4-hydroxy-6-oxo-tetrahydro-pyran-2-yl)-acetonitrile and other compounds obtainable from (4-hydroxy-6-oxo-tetrahydro-pyran-2-yl)-acetonitrile may suitably be used in the preparation of a pharmaceutical preparation, more in particular in the preparation of statins, more in particular in the preparation of Atorvastatine or a salt thereof, for instance its calcium salt. The invention also relates to (4-hydroxy-6-oxo-tetrahydro-pyran-2-yl)-acetonitrile and other compounds obtainable therefrom.