Huo H, Fu C, Harms K, Meggers E * Philipps-Universität Marburg, Germany and Xiamen
University, P. R. of China
Asymmetric Catalysis with Substitutionally Labile yet Stereochemically Stable Chiral-at-Metal
Iridium(III) Complex.
J. Am. Chem. Soc. 2014;
136: 2990-2993
Key words
chiral-at-metal iridium complexes - imidazoles - indoles
Significance
The widespread use of asymmetric catalysis in academia and industry can be directly
attributed to the vast array of synthetically and commercially available chiral ligands.
However, the utilization of chiral-at-metal complexes in asymmetric catalysis is relatively
underdeveloped. Here, the authors report the efficient synthesis of a chiral-at-iridium
catalyst and its application to an asymmetric Friedel–Crafts reaction.
Comment
The authors present the asymmetric Friedel–Crafts reaction of indoles and acyl imidazole
derivatives using a chiral-at-iridium complex as catalyst. The reaction proceeds with
excellent yields and selectivities by employing a low loading (1–2 mol%) of this interesting
catalyst. The authors suggest that once coordinated, the achiral ligands block the
re face of the indole, resulting in a highly selective si-face attack.
