Planar-Chiral Thioureas as Hydrogen-Bond Catalysts
作者:Jakob F. Schneider、Florian C. Falk、Roland Fröhlich、Jan Paradies
DOI:10.1002/ejoc.200901353
日期:2010.4
The synthesis of the first enantiopure planar-chiralthioureacatalysts is herewith described. New catalysts 1-3 were applied in asymmetric transformations, such as the Friedel-Crafts alkylation of indole, as well as in the transfer hydrogenation of nitroolefins. Bifunctional catalysts 2 and 3 exhibit enhanced activity in the investigated reactions, demonstrating their potential for organic synthesis
(S)-(-)- and (R)-(+)-4-Methyl-2-hydroxymethyl[2]paracyclo-[2](5,8)quinolinophane: Novel N,O-Planar Chiral Catalysts for the Enantioselective Addition of Diethylzinc to Aldehydes
Novel planar chiral N,O-ligands derived from (R)-(+)-and (S)-(-)-2,4-dimethyl[2]paracyclo[2](5,8)quinolinophane were synthesized and employed as catalyst in the enantioselective addition of diethylzinc to aromatic aldehydes. On the basis of the ee values, ranging from 30% to 75%, and the configuration of the obtained 1-phenyl-1-propanols a plausible structure of the transition state for the alkylation