Enantioselective Friedel-Crafts alkylation of indole derivatives catalyzed by new Yb(OTf)3-pyridylalkylamine complexes as chiral Lewis acids

Org Biomol Chem. 2011 Jan 21;9(2):497-503. doi: 10.1039/c0ob00461h. Epub 2010 Nov 11.

Abstract

New Yb(OTf)(3)-pyridylalkylamine complexes have been employed as chiral Lewis acids in the enantioselective Friedel-Crafts alkylation of indole derivatives with trifluoropyruvates. The influence of the substituents as well as the configuration of the ligands have been studied and allowed us to reach enantiomeric excesses up to 83%.