Catalytic and highly enantioselective Friedel-Crafts alkylation of aromatic ethers with trifluoropyruvate under solvent-free conditions

Structure: see text] 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.