Asymmetric Hydrogenation of Aromatic Ketones Catalyzed by the TolBINAP/DMAPEN−Ruthenium(II) Complex: A Significant Effect of <i>N</i>-Substituents of Chiral 1,2-Diamine Ligands on Enantioselectivity
mode of enantioface selection was interpreted by using transition state models based on the X-ray structure of the catalyst precursor. The chiral catalyst effected the hydrogenation of alkyl aryl ketones and arylglyoxal dialkyl acetals to afford the chiral alcohol in >99% ee in the best cases. Hydrogenation of racemic benzoin methyl ether with the chiral catalyst through dynamic kinetic resolution gave
Efficient isomerization: The title reaction was catalyzed by the [RuCl2(S)‐tol‐binap}(R)‐dbapen}]/KOH system in ethanol at 25 °C (see scheme). A series of E‐ and Z‐configured aromatic and aliphatic allylic alcohols, including a simple primary alkyl‐substituted compound (E)‐3‐methyl‐2‐hepten‐1‐ol, were transformed into the chiral aldehydes with at least 99 % ee. dbapen=2‐dibutylamino‐1‐phenylethylamine