Application Of Chiral Bridged Phenoxo-alkoxo Lanthanide And Aluminium Complexes On Asymmetric Epoxidation And Enantioselective1,4-addition Ofα,β-unsaturated Ketones To Diethyl Phosphite

The application of a series of lanthanide and aluminum complexes supported by bridged phenoxo alkoxo ligand on asymmetric epoxidation and enantioselective1,4-addition of α, βunsaturated ketones to diethyl phosphite. The bridged phenoxo alkoxo ligand used in this thesis is ((S)-2,4-di-tert-butyl-6-((2-(hydroxydiphenylmethyl) pyrrolidin-1-y1) methyl) phenol), and is abbreviated as H2L1.1. Chiral bridged phenoxo alkoxo lanthanide-lithium heterobimetallic complexes catalyzed asymmetric epoxidation of α, βunsaturated ketonesBridged phenoxo alkoxo lanthanide-lithium complexes [LnL2][{(THF)3Li}2(μ-Cl)][Ln=Yb (1), Y (2), Sm(3), Nd(4), Lu (5)] were found to be highly efficient catalysts for asymmetric epoxidation of α,β-unsaturated ketones to give the corresponding chiral epoxides with medium to high activity and excellent enantioselectivity under mild conditions. These catalysts show a wide range of scope to α,β-unsaturated ketones.2. Synthesis of chiral lanthanide and aluminum complexes supported by bridged phenoxo alkoxo ligand and their catalytic activity on enantioselective phospha-Michael addition of α,β-unsaturated ketones to diethyl phosphite.1. Reaction of anhydrous SCCI3with L1Li2in a1:2molar ratio in THF generated the scandium chloride L’ScClCTHF)(6).2. Reaction of complexes6with NaN(TMS)2in a1:1molar ratio afforded the unexpected complex L1Sc(L1H)(7). However, the reaction of mother liquid of complex6with NaN(TMS)2in a1:1molar ratio gave the complex[L1Sc(μ-OH)]2(THF)2(8).3. The complex L’AlMe (9) was prepared according to the literature in high isolated yield. However, the reaction of Et3A1with H2L1in1:1molar ratio in THF afforded complex [L’Al(μ-OH)]2(10). Complex10is similar to the complex (L1Al)2(μ-OH)(μ-OCH2CF3)(11), which was prepared by Feng Tao. 4. Complexes1-4,9and11were found to be highly efficient catalysts for asymmetric phospha-addition of aromatic aldehyde and diethyl phosphate, but the products have low enantioselectivity.5. Complexes1-6,9and10were found to be efficient catalysts for asymmetric phospha-Michael addition of α,β-unsaturated ketones and diethyl phosphate. Complexs1-4were found to be highly efficient catalysts for this asymmetric reaction, but the products have low enantioselectivity. However, when we chose complex6,78%yields and98%e.e. were achieved as we perform the reaction at-30℃.