25-HydroxyvitaminD2 as synthesized conveniently and stereoselectively for the first time by utilizing Sharpless' chiral epoxidation and the subsequent regio- and stereoselective methylation with lithium dimethylcuprate to introduce the desired chirality at C(24) and the reductive elimination of the vicinal hydroxy sulfone to introduce stereoselectively the E double bond at C(22) of the target molecule
The present invention is directed to novel processes for the preparation of paricalcitol to novel intermediates used in these processes, and to processes for preparation of the novel intermediates.