噻唑烷并手性(口恶)唑硼烷催化芳香酮的不对称还原反应的量子化学研究

采用量子化学从头计算方法研究了噻唑烷并手性口恶唑硼烷催化剂催化芳香酮的不对称还原反应 .选用Hartree Fock方法 ,在STO 3g基组下对体系进行了全优化计算 .该催化剂具有扭曲的椅式构型 ,反应中首先在N原子处与硼烷配位生成催化剂 硼烷加合物 ,然后再与芳香酮形成具有 3种构型的催化剂 硼烷 芳香酮加合物 ,其中最有利于H转移并决定还原产物手性的构型具有次低的能量 .H转移后形成的催化剂 烷氧基硼烷加合物中含有一个稳定的B O B N四元环 .

Quantum chemical study on enantioselective reduction of aromatic ketones catalyzed by chiral thiazolidino [3,4-c] oxazaborolidine

The ab initio molecular orbital method is employed to study the Enantios elective Reduction of aromatic ketones catalyzed by chiral thiazolidino [3,4-c ]oxazaborolidine. All the calculated systems are optimized completely at HF/S TO-3G level. The catalyst is a twisted chair structure and reacts with borane t o form catalyst-borane adduct, then this adduct and aromatic ketone form cataly s t-borane-ketone adduct. The catalyst-borane-ketone adduct has three differen t co nfigurations, but the configuration which is of the greatest advantage to a hydr ide transfer from the borane moiety to the carbonyl carbon is the one with the n ext low energy. After the hydride transfer, there is a catalyst-alkoxyborane a d duct with a B-O-B-N 4-membered ring formed, the 4-membered ring is stable, although there is strong tensile stress in the 4-membered ring.