Synthesis of Spiro[4.5]decane CF-Ring Analogues of 1α,25-Dihydroxyvitamin D₃

Abstract

A novel series of analogues of calcitriol (1) is developed featuring a spirocyclic central core resulting from C18/C21-connection and C15/C16-deletion (2a, 2b). The synthesis of the key intermediate involves an Eschenmoser rearrangement of an enantiomerically pure bromo-substituted cyclohexenol.