α-氯丙酸乙酯对映体与β-环糊精的主客体相互作用

Host-Guest Interactions of β-Cyclodextrin with Enantiomers of Ethyl α-Chloropropionates

运用量子力学PM3方法模拟α-氯丙酸乙酯((R/S)-ECPA)与β-环糊(β-CD)的主客体相互作用,探讨(R/S)-ECPA在β-CD上的手性识别机理.结果表明,(R/S)-ECPA对映体与β-CD形成稳定结合物的结合方式完全不同,(R)-ECPA位于β-CD空腔宽口端,形成缔合物;(S)-ECPA插入β-CD空腔内形成包结物.而且,(S)-ECPA与β-CD的结合稳定能低于(R)-ECPA与β-CD的结合稳定能.在(R/S)-ECPA与β-CD结合物中,(R/S)-ECPA中的手性碳接近葡萄糖单元的C2和C3.(R/S)-ECPA与β-CD之间的手性识别与葡萄糖单元的C2和C3所提供的手性环境和(R/S)-ECPA与β-CD结合的紧密程度密切相关.

Host-guest interactions of fl-cyclodextrin （β-CD） with enantiomers of ethyl α-chloropropionates （（R/S）- ECPA） were simulated using the quantum mechanics PM3 method. The chiral recognition mechanism of （R/S）-ECPA enantiomers on β-CD was investigated. Modeling results showed that the stabilization of complexes formed by （R/S）- ECPA enantiomers andfl-CD were different. （R）-ECPA was located on the cavity wide mouth end ofβ-CD to form an associated molecule, but （S）-ECPA inserted into the β-CD cavity to form an inclusion molecule. The stabilization energy of the （S）-ECPA and β--CD complex was lower than that of the （R）-ECPA and β-CD complex. The chiral carbon in the ECPA of （R/S）-ECPA and β-CD complexes was close to the C2 and C3 in the glucose unit. The chiral recognition mechanism was thus closely related to the chiral environment provided by C2 and C3 in the glucose unit and the degree of （R/S）-ECPA and β-CD inclusion.