Cells of the fungus, Geotrichum candidum, were immobilized on a water-absorbing polymer and used for stereoselective oxidation and reduction in an organic solvent using cyclohexanone, cyclopentanol or alkan-2-ols as additive. Enantiomerically pure (R)-1-arylethanols were obtained by the stereoselective oxidation of racemic 1-arylethanols, whereas enantiomerically pure (S)-1-arylethanols were obtained by the reduction of the corresponding ketones, in contrast to reduction in water by the free cells in which (R)- or (S)-1-arylethanols were produced in low ee.The reaction mechanism was investigated by measuring the partition of the substrates and products between the organic phase and aqueous phase in the polymer around which the cells were immobilized. Deuterated compounds were used to determine the role of the additives.
将真菌地霉菌(Geotrichum candidum)的细胞固定在
水吸收性聚合物上,并用于在有机溶剂中以
环己酮、
环戊醇或烷-2-醇作为添加剂进行立体选择性氧化和还原反应。通过立体选择性氧化外消旋1-芳基
乙醇,获得了对映体纯的(R)-1-芳基
乙醇,而通过对相应的酮进行还原,获得了对映体纯的(S)-1-芳基
乙醇,这与自由细胞在
水中的还原反应不同,后者仅产生低ee值的(R)-或(S)-1-芳基
乙醇。通过测量细胞固定在聚合物周围的有机相和
水分相中底物和产物的分布,研究了反应机制。使用
氘代化合物来确定添加剂的作用。