Abstract: The invention relates to a new method of preparing 16-dehydro vitamin D compounds having formula I ##STR1## wherein: R has the epi-configuration or the normal configuration and represents straight or branched C.sub.1-6 -alkyl, C.sub.2-6 -alkenyl, C.sub.3-6 -cycloalkyl, or an aromatic group optionally substituted with halogen, C.sub.1-3 -alkyl or alkoxy,Z is a saturated or unsaturated straight hydrocarbon group or oxahydrocarbon group containing 3-6 C-atoms which may be substituted with OH, F, alkyl (C.sub.1-3) or cycloalkyl (C.sub.3-5),R.sub.1 is hydrogen or an hydroxy protecting group,R.sub.2 is hydrogen or hydroxy, andA and B represent hydrogen or methyl, or together form the methylene group, to the new compounds having this formula and to new intermediates obtainable according to this process.