β-氨基酮不对称还原反应的理论研究  

Theoretical Study on the Enantioselective Reductions of β-Aminoketones

作　　者：樊建芬[1] 王秋霞[1] 沈宗旋[1] 

机构地区：[1]苏州大学化学系,苏州215006

出　　处：《Chinese Journal of Structural Chemistry》2004年第2期213-218,共6页结构化学（英文）

摘　　要：本文用AM1半经验分子轨道方法,首次从热力学和动力学角度研究了(R)-4-苄基-5,5-二苯基-1,3,2口恶唑硼烷催化还原系列β-氨基酮的反应,获得了CBS 反应机理各步的反应热及第二、第四步骤的反应活化能,结果表明第二步(催化配合物的形成)和第四步(产物的形成和催化剂的释放)为吸热反应,且第四步反应吸热较多,且活化能远高于第二步,同时发现CBS反应机理中第二步为控制反应产物构型取向的决定步骤,根据第二步反应中生成R和S型催化配合物的活化能之差可推测β-氨基酮分子中羰基对位推电子基的存在有利于获得高光学活性的氨基醇产物。The AMI-SCF MO method has been applied to study the enantioselective reduction of a series of b- aminoketones catalyzed by (R)-4-benzyl-5,5-diphenyl-1,3,2-oxazaborolidine, which contains four steps according to the CBS mechanism. The heat of reaction for each step and the activation energies of steps 2 and 4 of the enantioselective reduction have been obtained. It was found that steps 2 and 4 are endothermic, and their transition states and activation energies have been obtained and computed, respectively. The difference between the activation energies of step 2 resulting in R and S enantiomers (DEa) can be used to predict the optical activity of the final product of the enantioselective reduction.

关 键 词：β—氨基酮 不对称还原反应 AMI半经验分子轨道方法 热力学 动力学 反应机理 (R)—4—苄基—5 5—二苯基—1 3 2噁唑硼烷 

分 类 号：O621.25[理学—有机化学]