Process for preparing 24-homo-vitamin-D-derivatives

24-Homo-vitamin D derivatives of the formula I are described, in which R is a hydrogen atom, a hydroxyl or an acyloxy group with 1 to 8 carbon atoms, R and R are, independently of one another, a linear or branched alkyl group having 1 to 4 carbon atoms, a trifluoromethyl group or together are a saturated carbocyclic ring which is formed with carbon atom 25 and has 3 to 9 carbon atoms, R and R are, independently of one another, a hydrogen atom or an acyl group having 1 to 8 carbon atoms, and A and B are each a hydrogen or together are a second bond, and n is 1, 2, 3, 4 or 5 and to a process for their production, pharmaceutical compositions containing them and their use for the preparation of medicines. The compounds have proliferation-inhibiting and cell-differentiating action.