Molecular Mechanisms of Regio-and Stereoselections in the Reactions of Charcogen Coumpounds

点击翻译按钮获取中文摘要

As the interests of chemists expands to chemistry of the elements with higher atomic numbers, there appear many cases which cannot be interpreted by the valence concept that has been developed mainly for the first row elements. In this research, we have thoroughly reinvestigated the presenting reactivity theories and proposed a novel theoretical treatment of reactivity. We have defined the reactive orbital for each reactant molecule that participates actively in the formation of new bonds with a reagent, being localized around the reaction sites. In this way, we are able to estimate the local electron-donating and accepting potentials of the reaction sites, making it feasible to compare the reactivity of different molecules. With a view to proving the applicability of this theory and to making clearer the difference between charcogen componds and compounds with other elements around, we have applied the theory to the subsituent effects in the carbon pi conjugated species in which ample … More experimental data are available. It has been demonstrated that our new theory interprets the experimental observations much more satisfactorily compared with the existing theories. We have also applied the theory to the reaction of allylic compounds, obtaining successful results. To disclose the molecular mechanism and the factors controlling the reaction path for an asymmetric induction in sigmatropic rearrangements of selenium compounds, we have carried out ab initio MO calculations. Calculation have also been carried out on the reaction between methkyllithium and oxazolines having a ferrocenyl group, elucidating the reason why lithium adds preferentially to the nitrogen center. The results of these works are being prepared for publishing.On the experimental side, we have synthesized for the first time optically active [R,S ; R,S] - and [S,R ; S,R]-Bis [2- [1- (dimethyamino) ethyl] ferrocenyl] Diselenides and have demonstrated asymmetric selenoxide elimination and asymmetric [2,3] sigmatropic rearrangement take place very efficiently.To study asymmetric catalytic reacttions by the use of transition metal complexes, we have synthesized a variety of charcogen compounds having ferrocenyl groups. It was been shown hydrosilylation of ketones by using Rh (I) complexes having chiral ligands gives chiral alcohols at high yields. Less