Synthesis Of Chiral Organocatalysts And Their Applications In Asymmetric Michael Addition Reactions And Enantioselective Hydrophosphonylation Of Imines

Part 1 Design and Synthesis of Chiral Organocatalysts and their Applications in theAsymmetric Michael Addition Reactions of Ketones (aldehydes) to NitroolefinsⅠSynthesis of Chiral Betti Bases and their Applications in the Asymmetric MichaelAddition ReactionsEnantiomerically pure derivatives of Betti base, which catalyzed the Michael additionof cyclohexanone to nitroolefins with high diastereoselectivity (up to＞99: 1) andenantioselectivity (up to＞99% ee), were designed and prepared. The influence of thestructure and the loading of the catalyst, the amount of the additive, and the structure of thesubstrate have also been examined.ⅡSynthesis of Novel Chiral Thiourea-Pyrrolidine Catalyst and its Application in theAsymmetric Michael Addition ReactionsThe direct Michael addition reaction of ketones/ aldehydes with nitroolefins, catalyzed by a novel chiral pyrrolidine-thiourea catalyst is described. The desired1, 4-adducts were obtained in satisfactory yields with morderate enantioselectivities. Somefactors influencing diastereoselectivity and enantioselectivity were discussed.Part 2 Elementary study of enantioselective hydrophosphonylation of iminesSome new chiral organic catalysts were synthesized from natural L-phenylalanine andcinchona alkaloid, respectively. The influence of the structure of catalysts on theenantioselective hydrophosphonylation of imines was studied elementarily. In addition, HPAs were found to be efficient catalysts for one-pot three-component synthesis ofα-amino phosphonates in good yields. The influence of the loading of HPAs, reactionsolvent, the structure of aldehydes and amines were studied. Part 3 Preparation of Supported Proline-derived Chiral Catalysts And TheirCatalytic Application in Asymmetric Aldol ReactionsTwo new silica-supported methylcellulose-chiral small organic molecule complexeshave been prepared and found to be effective catalysts for asymmetric aldol reactions ofacetone with benzaldehydes at room temperature. The desired aldol adducts were obtainedin good yield with ee up to 86.8%. These catalysts were very stable and could be recycledfor several times.