d－生物素的立体专一性全合成研究

STUDIES ON STEREOSPECFIC TOTAL SYNTHESIS OF d-biotin

对ｃｏｎｆａｉｏｎｅ的ｄ－生物素（１）全合成进行了改进，从半胱氨酸计算，总收率３．７％。５与４－溴代三苯膦丁酸甲酯进行Ｗｉｔｔｉｇ－Ｓｃｈｌｏｓｓｅｒ缩合反应可立体专一性地转化成反式－烯（６）。以叠氮三甲基硅烷代替叠氮化锂亲核进攻９分子中Ｃ３－溴原子，可显著地提高顺式－叠氮内酰胺１０的收率。

A modified stereospecific total synthesis of d-biotin from L-(+)-cysteine based on Confalone’ s method was described, Witting-Schlosser olefination of the aldehyde(5) with Witting reagent derived from carbomethoxypropyl-triphenylphosphonium bromide ,after acidic work-up,furnished transolefin(6 ) stereospecifically in 72% yield.Treatment of the bromolactam(9) with azidotrimethylsilane instead of lithium azide via SN2 nucleophilic substitution increased the yield of cis azido lactam(10).The overall yield of d-biotin was 3.7%from cysteine.