Asymmetric Friedel–Crafts reactions of indoles or pyrroles with coumarin-3-carboxylates catalyzed by Cu(OTf)2 complexes with chiral bis(oxazoline) ligands have been developed. The highest ee (up to 82%) was achieved for indole with a nitro derivative of coumarin-3-carboxylate.
Key words
enantioselective catalysis - BOX ligands - copper - 3,4-dihydrocoumarins - asymmetric Friedel–Crafts reaction