Preparation and biological activity of 24-epi-26,26,26,27,27,27-hexafluoro- 1 alpha,25-dihydroxyvitamin D2.

A new fluorinated analog of vitamin D2, 24-epi-26,26,26,27,27,27-hexafluoro- 1 alpha,25-dihydroxyvitamin D2, was efficiently synthesized starting from (R)-4-isopropyl-3-propionyl-2- oxazolidinone with high stereochemical control. In all four physiological test systems, the fluorinate vitamin D2 analog was found to be slightly less active than 1 alpha,25-dihydroxyvitamin D3.