ChemInform Abstract: Synthesis of 24-Oxavitamin D3 and 1α-Hydroxy-24-oxavitamin D3

Coupling of the CD fragment, ketone 6 (obtained by partial synthesis from vitamin D2), either directly (Horner-Wittig route) or via the derived enol triflate (dienyne route) with the appropriate A-ring fragment, phosphine oxide anion 7 or enyne 10, is the key step in the syntheses of 24-oxavitamin D3 (1d) and 1α-hydroxy-24-oxavitamin D3 (1e), respectively. © 1993.