Activation of Chiral (Salen)TiCl2 Complex by Phosphorane for the Highly Enantioselective Cyanation of Nitroolefins.

We report that phosphorane can activate (salen)TiCl2 complex to achieve unprecedented excellent enantioselectivity and a broad substrate scope in the cyanation of nitroolefins. Our cyanating reagent Me2(CH2Cl)SiCN proves to be more active than TMSCN in this reaction, allowing 11 β-aliphatic nitrolefins and 12 β-CF3 nitroolefins (either β-aryl or aliphatic) to work well to give the corresponding tertiary or quaternary β-nitronitriles with high to excellent enantioselectivity.