丹参素冰片酯的不对称合成研究

目的 不对称合成丹参素冰片酯。方法 以3,4-二羟基苯甲醛为原料，经苄基保护及 Knoevenagel 缩合反应得到(E)-3-(3,4-二苄氧基苯基)丙烯酸(3)，经过酰化反应得到酰氯后与天然冰片反应生成(E)-3-(3,4-二苄氧基苯基)丙烯酸冰片酯(4)，通过Sharpless不对称双羟化反应构建手性中心，得到高光学纯度的3-(3,4-二苄氧基苯基)-2,3-二羟基丙酸冰片酯衍生物(5)，最后经选择性催化加氢及脱保护得到目标产物。结果与结论 目标化合物经高效液相手性色谱柱分析ee为97%，所得化合物的结构通过1H-NMR、13C-NMR、MS证实，该合成方法操作简单、条件温和、光学产率高。

Asymmetric synthesis of Danshensu borneol ester

The asymmetric synthesis of Danshensu borneol ester(1) was achieved. Intermediate (E)-3-(3,4-dibenzyloxyphenyl) acrylic acid (3) has been synthesized by taking 3,4-dihydroxybenzaldehyde as starting material, which was reacted with benzyl chloride and propandioic acid. Treatment of (3) with thionyl chloride and borneol to attain (E)-3-(3,4-dibenzyloxyphenyl)acrylic acid borneol ester (4) in the mild conditions. Then the asymmetric synthesis of chiral molecule 3-(3,4-dibenzyloxyphenyl)-2,3-dihydroxy propionic acid borneol ester (5) was achieved by Sharpless asymmetric dihydroxylation of (4) in excellent enantionmeric excesses. Finally, selective hydrogenation of (5) provides the desired product (1). The enantionmeric excesses (ee=97%) have been analysed by the chiral HPLC columns. The structure of products were characterized by 1H-NMR, 13C-NMR and high-resolution MS techniques. The method contains the merits of easy manipulation and high enantioselectivity.