Yanagisawa A1, Fujinami T, Oyokawa Y, Sugita T, Yoshida K.
Org Lett. 2012 May 18;14(10):2434-7. doi: 10.1021/ol300146k. Epub 2012 May 8.A catalytic asymmetric N-nitroso aldol reaction of γ,δ-didehydro-δ-lactones with nitrosoarenes was achieved using chiral tin dibromide as the chiral precatalyst and sodium ethoxide as the base precatalyst in the presence of ethanol. Optically active α-hydroxyamino ketones with up to 99% ee were regioselectively obtained in moderate to high yields from various δ-aryl-substituted γ,δ-didehydro-δ-valerolactones and o-substituted nitrosoarenes.