吡咯烷并手性噁唑硼烷催化芳香酮的不对称还原机理的量子化学研究

不对称催化还原;吡咯烷并手性噁唑硼烷催化芳香酮的不对称还原机理的量子化学研究

Quantum Chemical Study on the Mechanism of Enantioselective Reduction of Aromatic Ketone Catalyzed by Chiral Pyrrolidino [3,4-c] oxazaborolidine

In quantum chemical studies on enantioselective reductions small model molecules are comonly used to substitute the reactants as reported in literatures. It results in certain neglect of important chemical information. In this paper, the semi empirical AM1 molecular orbital method is used to study the enantioselective reduction of aromatic ketone catalyzed by chiral pyrrolidino oxazaborolidine without model substituents. As illustrated, this enantioselective reduction is exothermic . In the transition states of hydrogen atom from the borane moiety to the carbonyl carbon of aromatic ketone, there is a 6 membered B-N-B-H-C-O ring in a twisted chair structure . The controlling step for the reduction is the decomposition of the catalyst:alkoxyborane which contains a B-O-B-N ring.