The stereocontrolled reduction of α- and β-keto esters using micro green algae was accomplished by a combination of the cultivation method and the introduction of an additive. The reduction of ethyl pyruvate and ethyl benzoylformate by the photoautotrophically cultivated Chlorella sorokiniana gave the corresponding alcohol in high e.e. (>99% e.e. (S) and >99% e.e. (R), respectively). In the presence of glucose as an additive, the reduction of ethyl 3-methyl-2-oxobutanoate by the heterotrophically cultivated C. sorokiniana afforded the corresponding (R)-alcohol. On the other hand, the reduction in the presence of ethyl propionate gave the (S)-alcohol. Ethyl 2-methyl-3-oxobutanoate was reduced in the presence of glycerol by the photoautotrophically cultivated C. sorokiniana or the heterotrophically cultivated C. sorokiniana to the corresponding syn-(2R,3S)-hydroxy ester with high diastereo- and enantiomeric excess (e.e.). Some additives altered the stereochemical course in the reduction of α- and β-keto esters.
通过结合培养方法和添加剂,利用微型绿藻实现了α-和β-
酮酯的立体控制还原。光能自养培养的小球藻还原
丙酮酸乙酯和
苯甲酰甲酸乙酯时,可获得高浓度的相应
醇类(分别为 >99% 的浓度 (S) 和 >99% 的浓度 (R))。在有
葡萄糖作为添加剂的情况下,异养培养的苏氏小球藻还原 3-甲基-2-氧代
丁酸乙酯,可得到相应的(R)-醇。另一方面,在有
丙酸乙酯存在的情况下进行还原则会产生 (S)-醇。2- 甲基-
3-氧代丁酸乙酯在有
甘油存在的情况下,被光能自养的高粱苣苔或异养的高粱苣苔还原成相应的对映体和非对映体过量(e.e.)的合成-(2R,3S)-羟基酯。一些添加剂改变了α-和β-
酮酯还原的立体
化学过程。