Enantioselective Nitroso Aldol Reaction Catalyzed by a Chiral Phosphine–Silver Complex

A catalytic asymmetric O-nitroso aldol reaction of alkenyl trifluoroacetates with nitrosoarenes was achieved by using QuinoxP*·AgOAc [(R,R)-QuinoxP* = (–)-(R,R)-2,3-bis(tert-butylmethylphosphino)quinoxaline] as the chiral precatalyst and N,N-diisopropylethylamine as the base precatalyst in the presence of methanol. Optically active α-aminooxy ketones with up to 99 % ee were regioselectively obtained in moderate to high yields by the in situ generated chiral silver enolates.