A new strategy for the synthesis of (1R,3R,7E,22E)-19-nor-9,10-secoergosta-5,7,22-trieno-1,3,25-triol (paricalcitol) was developed. Three advanced intermediates (synthon A, synthon CD and synthon S) were used as precursors. The paricalcitol produced showed high enantiomeric purity and met pharmaceutical requirements.