Efficient Access to Trifluoromethyl Diarylpyrrolines and their N‐Oxides through Enantioselective Conjugate Addition of Nitromethane to β,β‐Disubstituted Enones

The cupreidinium salt 1 catalyzes the highly enantioselective conjugate addition of nitromethane to β-aryl-β-trifluoromethyl aryl enones (2). The biologically important chiral pyrrolines 4 and N-oxide 5, having a trifluoromethylated all-carbon quaternary chiral center, were easily synthesized from the key intermediate (R)-3 in high to excellent yields. M.S.=molecular sieves.