光学活性的19-失碳-1α,25-二羟基维生素D_3 A环关键中间体的合成

Synthesis of an Optically Active Intermediate of A ring for 19 Nor 1α,25 Dihydroxyvitamin D 3

报道以价廉易得的Ｄ（＋）木糖为手性源，经５步反应，立体选择性地合成１９失碳１α，２５二羟基维生素Ｄ３Ａ环关键中间体（２Ｓ，４Ｓ）１，５二氯２，４戊二醇（５）的方法．该方法具有收率高。

Synthesis of an optically active intermediate of A ring for 19 nor 1α,25 dihydroxyvitamin D 3 has been achieved in 5 steps,starting from readily available,inexpensive D (+) xylose.The new method is comparatively more favourable than the previors method as regards to the yield and the price of the reagent.