The Theoretical Investigation Of Oxidative Kinetic Resolution Of Secondary Alcohols Catalyzed By (-)-sparteine-Pt Complexes

Chiral alcohols are ubiquitous in chemical industry, such as synthetic organic chemistry, agricultural chemicals and pharmaceutical industry. For the past 10 years, highly efficient asymmetric hydrogenation of prochiral ketones to attain chiral alcohols, Besides that, oxidative kinetic resolution of secondary alcohols is also another feasible approach giving chiral alcohols. Recently, remarkable progress has been made in oxidative kinetic resolution of secondary alcohols by chiral amine and phosphine ligands combine with Pd, however, rarely for Pt. So, the mechanism of oxidative kinetic resolution of secondary alcohols (1-phenylethanol) catalyzed by (-)-sparteine-PtC;2 complexes is characterized in detail both in gas phase and solution.The whole paper consists of four chapters. Chapter 1 is mainly about the development of oxidative kinetic resolution of secondary alcohols, followed by the mechanism study for the reaction of PH2- with OCS and CS2 in gas-phase.In chapter 2, The theory of quantum chemistry and calculation methods of this paper that offer us with userful and reliable quantum methods. The systems have been investigated using Density Functional Theory (DFT), second-order M(?)ller-Plesset perturbation theory and Transition States Theory. The structures of the reagents, products and transition states along the reaction paths have been obtained together with the potential energy surface and thermodynamic datum. The reaction mechanism has been discussed using these data which provide effective informations for expenments.In chapter 3, theoretical study of oxidative kinetic resolution of secondary alcohols (1-phenylethanol) catalyzed by (-)-sparteine-PtCl2 complexes is characterized in detail in both gas phase and solution. The results indicate that the reaction processes comprise the coupling 1-phenylethanol with catalysts, deprotonation and P-hydride elimination whether it is (R)-phenylethanol or (S)-phenylethanol. Meanwhile, the P-hydride elimination acts as the determining step in the reaction. As compared the structures and energies of (R)-phenylethanol with (S)-phenylethanol catalyzed by (-)-sparteine-PtCl2 complexes in gaseous phase, the strong interactions of P-agostic and hyper conjugation effect of Pt-Oâ†'C-Hβin the determining step generate the more stable state of TS2R, also the selectivity is calculated of 15.18. Moreover, the effects of toluene and chloroform solvents are investigated by PCM method. Our calculations show an increase in dielectric strength, however, the decrease of the energies for rate determining step as well as the selectivity. (-)-sparteine-PtCl2 is not a good catalyst when compared to the (-)-sparteine-PdCl2 complexes in oxidative kinetic resolution of secondary alcohols.In chapter 4, the mechanism for the reaction of PH2- with OCS and CS2 have been characterized in detail,using the second-order M(?)ller-Plesset perturbation theory (MP2) combine with 6-311++G(d,p) basis sets, together with DFT(B3LYP) theory, also the single-point energies have also been refined at the CCSD/6-311++G(d,p) level to get more accurate energies using the MP2/6-311++G(d,p) optimized geometries. The favorable rotes are chose for products H2PS+CO, PCO-+H2S, PCS-+H2O, H2PCOS and PCS-+H2S, H2PCOS, PS-+H2CS. The results indicate that the main products of H2PS-+CO are attribute to the low energies and the least one transition state; products PCO-+H2S are apt to the second pathways of the Channel 2, a less products of H2PCOS could be exist. The products PCS-+H2O could not be detected for the higher energies of intermediates and transition states of both channels. As to the reaction of PH2-+CS2, the main products are PCS-+H2S, H2P+COS and PS+H2CS2 are less ones. The comparison between the products to attain the well results with experiments.