Theoretical Studies On Metal-Bisoxazoline Catalyzed Asymmetric 1,3-Dipolar Cycloaddition Reactions

1,3-dipolar cycloaddition reaction is the most useful reaction in fundmental theory of organic chemistry and organic synthesis. The 1,3-dipolar cycloaddition of nitrones with alkenes is one of the most studied reactions, among all the cycloadditions. It provides the most efficient method to prepare isoxazolidines that are widely used as starting compounds in organic synthesis, in particular for building natural products.The rapid developments of complex in the field of catalytic enantioselective 1,3-dipolar cycloaddition reactions which have occurred during the recent years are reported.A series of catalysis has been applied for 1,3-dipolar cycloaddition reactions of nitrons with electron-deficient and electron-rich alkenes, respectively. In several cases a high degree of control of both thediastereoiosmer and enantioselectivity has been achieved in both Diels-Alder reactions and 1,3-dipolar cycloaddition reactions.In this thesis, theoretical study approach has been used to study with Materials Stodio on the workstation sgi3800.Theoretical investigations are carried out on the cycloaddition reaction between vinyl ethyl ether and the pro-formed complexes which formed by the reaction of chiral copper(II)- or zinc(II)-bisoxazolines with N-benzyl-C-ethoxylcarbonyl nitrone. The influences of the frontier molecular orbitals and optimizing geometry of the pro-formed complexes on the reaction rates and endo/exo selectivity are discussed, and a reasonable explanation about the steroselectivity of 1,3-dipolar cycloaddition reaction in the presence of copper (II)- or zinc(II)-bisoxazolines catalyst is given. The influence of catalytic and no-catalytic reaction rate on the steroselectivity is also discussed.