Direct, Catalytic Enantioselective Nitroaldol (Henry) Reaction of Trifluoromethyl Ketones:  An Asymmetric Entry to α-Trifluoromethyl-Substituted Quaternary Carbons

Herein we describe the first direct, catalytic enantioselective nitroaldol (Henry) reaction of simple α-trifluoromethyl ketones with nitromethane using a chiral monometallic lanthanum(III) triflate salt complex, namely [(Δ,S,S,S)-Binolam]₃·La(OTf)₃, as enantioselective catalyst. The resulting α-trifluoromethyl tertiary nitroaldols were obtained in moderate to high yields (up to 93%) and enantioselectivities (up to 98% ee). These adducts are versatile chiral building blocks and may be reduced (NiCl₂/NaBH₄) to their β-amino-α-trifluoromethyl tertiary alcohols without loss of enantiomeric purity.