CL : Vol. 36 (2007) , No. 9 p.1082

Asymmetric Catalytic Redox System: Tethered Bis(8-quinolinolato) (TBOx) Chromium(III/II) Complexes

1) Department of Chemistry, the University of Chicago

(Received July 3, 2007)

The TBOxCr^IIICl/TBOxCr^II system is ideal for catalytic asymmetric redox process. Because of the electron density of the TBOxH ligand high turnover numbers are expected, hence allowing decrease in the chromium catalyst loadings and acceleration of the reaction rate. High reactivity and high diastereo-/enantioselectivity are shown in asymmetric pinacol coupling reactions of aldehydes, asymmetric NH allylation reaction of aldehydes, asymmetric allenylation reactions of aldehydes, and some other reactions. These proceed exceedingly efficiently catalyzed by the TBOxCr^IIICl redox system due to the well-designed chiral environment of the ligands and the cis-β configuration of the center Cr metal.

TBOxCr<sup>III</sup>Cl/TBOxCr<sup>II</sup> system is an ideal for catalytic asymmetric redox system. Because of the electron density of the TBOxH ligand, high turnover numbers are expected and hence allow decrease in the chromium catalyst loadings and acceleration of the reaction rate. Furthermore, high reactivity and high diastereo-/enantioselectivity are shown in asymmetric pinacol coupling reactions of aldehydes, asymmetric NH allylation reaction of aldehydes, asymmetric allenylation reactions of aldehydes, and some other reactions, which proceed exceedingly efficiently catalyzed by the TBOxCr<sup>III</sup>Cl redox system, due to the well-designed chiral environment of the ligands and the cis-β configuration of the center Cr metal.

TBOxCr^IIICl/TBOxCr^II system is an ideal for catalytic asymmetric redox system. Because of the electron density of the TBOxH ligand, high turnover numbers are expected and hence allow decrease in the chromium catalyst loadings and acceleration of the reaction rate. Furthermore, high reactivity and high diastereo-/enantioselectivity are shown in asymmetric pinacol coupling reactions of aldehydes, asymmetric NH allylation reaction of aldehydes, asymmetric allenylation reactions of aldehydes, and some other reactions, which proceed exceedingly efficiently catalyzed by the TBOxCr^IIICl redox system, due to the well-designed chiral environment of the ligands and the cis-β configuration of the center Cr metal.