关键词: 胆甾醇, 立体选择性, 锇, 维生素D3, 猪去氧胆酸, 羟基化合物, 合成药, 骨质疏松症, 不对称反应

A stereoselective synthesis of (24R,25R)-2425,26-trihydroxycholesterol, which is an important intermediate for the synthesis of vitamin D3 analog, through 7 steps, from I (R = H) was reported. The key step is osmium-catalyzed asym. dihydroxylation of compound I (R = 4-ClC6H4CO). The total yield is 40%.

Key words: CHOLESTEROL, STEREOSELECTIVITY, OSMIUM, VITAMIN D3, HYODEOXYCHOLIC ACID, HYDROXYL COMPOUNDS