水/有机溶剂双相中杏仁醇腈酶促不对称合成(R)-苯乙氰醇

 研究了水／有机溶剂双相中来源于杏仁的（R）－醇腈酶催化苯\r\n甲醛与HCN不对称合成（R）－苯乙氰醇，系统探讨了有机溶剂、水相与\r\n有机溶剂相体积比、水相pH值和反应温度对反应速度、转化率和产物光\r\n学纯度的影响．结果表明，上述因素对醇腈酶促不对称合成（R）－苯\r\n乙氰醇反应均有显著影响．异丙醚为该反应最好的有机溶剂，水相与有\r\n机溶剂相体积比以1／2为宜，适宜的pH值为3．4，最佳反应温度为0～\r\n5℃．在该优化反应条件下，反应转化率和产物的光学纯度均高达99％\r\n以上．

Asymmetric Synthesis of (R)-Mandelonitrile Catalysed by (R)-Oxynitrila se from Almond in Water/Organic Solvent Biphase Systems

The asymmetric synthesis of (R)-mandelonitrile from benzaldehyde and hydrog en cyanide using (R)-oxynitrilase from bitter almond in water/organic solve nt biphase systems was studied. The effects of organic solvents, volume ratio of water phase to organic phase, pH value of aqueous phase and reaction temperatur e on the initial reaction rate, the final conversion and enantiomeric purity of the product were explored. All above mentioned facts had important effects on th e reaction. Diisopropyl ether is found to be the best organic solvent for the re action. The optimum volume ratio of water phase to organic phase, pH and reactio n temperature are 1/2, 3.4 and 0～5 ℃ respectively for the reaction. Under the se conditions, both the conversion rate and enantiomeric excess are as high as 99%.