Stereoselective introduction of hydroxy groups into the cholesterol side chain. Preparation of (24R)- and (24S)-24,25-dihydroxy- and (25R)- and (25S)-25,26-dihydroxyvitamin D3 by asymmetric synthesis
Stereoselective introduction of hydroxy groups into the cholesterol side chain. Preparation of (24R)- and (24S)-24,25-dihydroxy- and (25R)- and (25S)-25,26-dihydroxyvitamin D3 by asymmetric synthesis
复制标题
将羟基立体选择性引入胆固醇侧链。
DOI：
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发表时间：
1983
期刊：
影响因子：
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通讯作者：
N. Ikekawa
中科院分区：
文献类型：
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作者：
N. Koizumi;M. Ishiguro;M. Yasuda;N. Ikekawa
通过烯丙醇(4)的不对称环氧化反应合成的24,25-环氧-26-羟基-3β-四氢吡喃氧胆碱-5-烯（7a）和（8a），以及烯酮(6)的不对称还原合成的24-羟基-3β-四氢吡喃氧胆碱-5,25-二烯（11）和（12），立体选择性地转化为25,26-和24,25-二羟基胆固醇衍生物，可转化为25,26-和24,25-二羟基维生素D3。发现26-苯甲酰氧基-24,25-环氧化物（7b）， （8b），（25）和（26）具有高度立体选择性的环氧化物裂解，并在C-24位点保留。
24,25-Epoxy-26-hydroxy-3β-tetrahydropyranyloxycholest-5-enes (7a) and (8a), prepared by asymmetric epoxidation of the allylic alcohol (4), and 24-hydroxy-3β-tetrahydropyranyloxycholesta-5,25-dienes (11) and (12), synthesized by asymmetric reduction of the enone (6), were stereoselectively converted into 25,26- and 24,25-dihydroxycholesterol derivatives, which could be transformed into 25,26- and 24,25-dihydroxyvitamin D3. The highly stereoselective epoxide cleavage of 26-benzoyloxy-24,25-epoxides (7b), (8b), (25), and (26) was found to proceed with retention at C-24.