环糊精介入酵母细胞催化芳香酮的不对称还原反应

Asymmetric Reduction of Aromatic Ketones by Yeast Cells Catalyzed in the Presence of Cyclodextrins

以苯乙酮、苯丙酮、4-甲基苯乙酮和4：氯苯乙酮为底物，研究了酵母细胞催化芳香酮的不对称还原反应，分别考察了添加剂β-环糊精和羟丙基-β-环糊精对酵母细胞催化芳香酮的不对称还原反应的影响，结果表明芳环上取代基的空间效应和电子效应对转化率和对映体过量值有显著的影响．环糊精是通过提高酵母液的催化效率和对底物形成包结来影响反应结果的，其中底物芳环对位有无取代基是添加剂影响反应结果的关键因素．环糊精加入量根据底物的不同在3-20mmol／L之间较合适．

The asymmetric reduction of aromatic ketones catalyzed by yeast cell was studied using acetophenone, propiophenone, 4＇-methylacetophenone and 4＇-choloracetophenone as substrates. The influences of additive β-cyclodextrin and hydroxypropyl-β-cyclodextrin on asymmetric reduction of aromatic ketones were also investigated respectively. The results show that the conversion rate and the enantiomeric excess value were markedly affected by both steric effect and electronic effect of substituted group. The reaction results were affected by cyclodextrions through enhancing the catalytic efficiency of yeast fermentation broth and inclusion with the substrate, among which p-substituted group of the substrate aromatic cycle is the key factor. Suitable amount of joined cyclodextrins is 3-10 mmol/L according as different substrates.