Asymmetric α-chlorination of β-ketoesters using bifunctional ammonium salt catalysis

Chiral urea-quaternary ammonium salt hybrid organocatalysts were tested for their capability to control asymmetric α-chlorination reactions of β-ketoesters. After a careful screening we identified a structurally simple catalyst derivative that allowed us to obtain enantiomeric ratios up to 90:10 under operationally simple conditions using just 1 mol% of the catalyst. Graphical abstract