苯甲酮不对称还原反应的理论研究

本文用AM1分子轨道方法研究了1,3,2-噁唑硼烷对苯甲酮的不对称催化还原.反应经历了噁唑硼烷-硼烷配合物的形成及其与苯甲酮的结合、氢转移及脱去噁唑硼烷形成手性产物二级醇-硼烷配合物四步过程.获得了各步的反应热、速度控制步骤的过渡态结构和位能曲线及其相应的反应活化能,计算发现反应机理中的第3步氢转移产物有四员环结构特征.

Theoretical Study on the Enantioselective Reduction of Phenyl Methyl Ketone

The enantioselective reduction of phenyl methyl ketone catalyzed by 1,3,2-oxazaborolidine has been studied by AM1-SCF MO method. The reaction goes through the formation of oxazaborolidine-borane adduct and its coordination with phenyl methyl ketone, H transfer and formation of secondary alcohol-borane complex by elimination of oxazaborolidine. The reaction heat of each step has been computed. The transition state, potential energy curve and corresponding activation energy of the velocity-controlling step were obtained. Meanwhile, it was found that the product of hydrogen transfer in the third step of enantioselective reduction of phenyl methyl ketone is characterized by the structure with a tetra-atomic ring.