Conjugated Enones Participated Cyclizations And Reduction Catalyzed By Organocatalyst And Synthesis Of New Chiral Tertiary Phosphines

This thesis mainly consists of three parts.In the first part, we have developed a novel asymmetric [3+3] cycloaddition of β-ketoesters and 2-(1-alkynyl)-2-alken-l-ones for the construction of polysubstituted 4H-pyrans by using cyclohexyldiamine-based bifunctional thiourea-tertiary amine as catalyst. Under this mild and eco-friendly conditions, a wide range of polysubstituted 4H-pyrans were obtained in moderate yields with good enatioselectivities.In the second part, during the course of asymmetric nucleophilic phosphines catalysis, we have discovered that Ph2PMe can serve as reducing agent for the selective reduction C=C of 3-aroyl acrylates and 2-ene-1,4-diones in the presence of water. This method has show good functional group tolerance and diverse 1,4-diketone products were obtained in moderate to excellent yields. In addition, we also have developed a one-pot strategy for the synthesis of a wide range of 2,5-substituted pyrroles.In the third part, our group focused on the synthesis of chiral methylpropane-2-sulfinamide phosphine catalysts. The catalysts based on diphenyl methyl phosphine or triphenylphosphine still have limitations for some recations because of their weaker nucleophilicity. Therefore, we tried to synthesize a new type of P-chirogenic compounds based on dimethyl phenyl phosphine. The enantioselective [4+1] cycloaddtion of conjugated enones catalyzed by this new P-chirogenic organocatalysts were preliminarily studied. Futher studies are still in progress.