Research On Desymmetrization Of Polyhydroxylated Compounds Mediated By Chiral Brnsted Acid

Desymmetrization of polyhydroxylated compounds mediated by chiral Bronsted acid is studied in this thesis which is composed of four parts:Part 1:Asymmetric transacetalization catalysed by new Bronsted acidsAsymmetric transacetalization catalysed by new Bronsted acids for the synthesis of Glycerol derivatives is reported. Moderate yields and high enantioselectivity were obtained.Part 2:Desymmetrization of prochiral allenic diols by cooperative binary catalysis of Pd(OAc)2 and chiral phosphoric acidThe first non-enzymatic desymmetrization of prochiral allenic diols via cooperative binary catalysis of Pd(OAc)2 and (R)-STRIP is reported. This method gave quickly access to a series of optically active disubstituted dihydrofurans through 5-endo-trig cyclizations. High yields and good to excellent enantioselectivity were obtained with a broad range of substrate scope.Part 3:Catalytic enantioselective manipulation of tetrol:general approach to chiral vicinal all-carbon quaternary stereogenic centersHighly enantioselective catalytic protocol for selective manipulation of tetrol through chiral phosphoric acid mediated oxidative desymmetrization is reported. This efficient approach provides a generally efficient access to vicinal all-carbon quaternary stereogenic centers structural motifs, as well as structure containing vicinal tertiary and all-carbon quaternary stereocenters. Gram-scale reaction further demonstrating the synthetic utility of this method is documented.Part 4:Research on chemical transformations of chiral compounds with vicinal all-carbon quaternary stereogenic centers and total synthesis of HybocarponeIn this part, research on chemical transformations of chiral compounds with vicinal all-carbon quaternary stereogenic centers is reported. We also report the preliminary attempt to the total synthesis of natural product Hybocarpone and the core furan structure of Hybocarpone with two vicinal quaternary carbon centers was built up.