Synthesis of 1α,25-dihydroxyvitamin D3 analogues with α-hydroxyalkyl substituents at C12

▸ New vitamin D analogues with a second α-side chain at C12 were synthesized. ▸ Functionalization at C12 by Johnson-Claisen rearrangement of an allylic alcohol. ▸ A-ring and triene system built by tandem Pd-catalysed cyclization and Suzuki coupling.