Efficient and Convergent CouplingRoute for the Short-step Synthesis of Enantiopure 2α-and 2β-Alkylated 1α,25-Dihydroxy-19-norvitaminD3Analogues

Novel efficient synthesis of several enantio-pure 2-alkylated 1α,25-dihydroxy-19-norvitamin D 3 analogues through radical introduction of 2-alkyl chain and C 5 -C 6 position coupling using Julia-type olefination as key steps was established starting from commercially available (-)-quinic acid as a chiral pool.