The Theorical Study On The Formation About β-CD-Styrene Oxide And β-CD-N-Tosyl-2-Phenyl-Aziridine, And HBr-Induced Ring Opening Of Styrene Oxide In The Presence Of β-CD

The primary quantum study on the formation aboutβ-CD-styrene oxide andβ-CD-N-tosyl-2-phenyl-aziridine, and the HBr-induced ring opening of styrene oxide in the presence ofβ-CD is carried out.Firstly, the quantum chemistry methods were employed to study supramolecular systems ofβ-CD-N-tosyl-2-phenyl-aziridine andβ-CD-styrene oxide. The results show that, when the phenyl groups of styrene oxide and N-tosyl-2-phenyl-aziridine are inclined to the secondary rim ofβ-CD, the systems are more stable. And the property of electron density analyzed by topological study indicates that hydrogenbond was formed between the host and guest molecules when the phenyl group of guest molecules point to the secondary rim ofβ-CD. As a result, it is suggested that the orientation effect on styrene oxide and N-tosyl-2-phenyl-aziridine in the inner phase ofβ-CD might mostly be attributed to the dipole action and H-bond action between the host and guest molecules.Then the reaction mechanisms about styrene oxide, in a free state or encaged in the cavity ofβ-CD, induced opening its ring by HBr were theoretically investigated with the quantum chemistry calculation methods. Under usual conditions, the main ring opened addition product will be 2-bromine-2-phenylethanol and undergoing two different pathways. However, after that the styrene oxide driven by the force of dipole-dipole interactions was contained in the inner of P-CD, the dominant product will be 2-bromine-1-phenylethanol involved in a concerted process. The causes which result in the regioselectivity have been analyzed according to the reaction environment.