Catalytic and Highly Enantioselective Friedel−Crafts Alkylation of Aromatic Ethers with Trifluoropyruvate under Solvent-Free Conditions

Highly enantioselective Friedel−Crafts alkylation of simple and aromatic ethers (4a−l) with 3,3,3-trifluoropyruvate (3) was accomplished by using chiral (4R,5S)-DiPh-BOX(1b)−Cu(OTf)2 complex (1 mol %) as a catalyst under solvent-free conditions. Excellent yields and enantioselectivities (90−93% ee, after recrystallization up to 99% ee) of the Friedel−Crafts alkylation products were obtained.