Catalytic Enantioselective O‑Nitrosocarbonyl Aldol Reaction of β‑Dicarbonyl Compounds

The first example of a Cu-catalyzed asymmetric O-nitrosocarbonyl aldol reaction is described. This novel protocol allows convenient access to highly enantioenriched α-hydroxy-β-ketoesters including the antibacterial natural product kjellmanianone (up to 99% ee). MnO₂ was introduced as a mild efficient oxidant for the in situ generation of nitrosocarbonyl species from hydroxamic acid derivatives.