Highly enantioselective dimerization of α,β-enones catalyzed by a rigid quaternary ammonium salt

The chiral quaternary ammonium salt 1 served as a phase-transfer catalyst for the enantioselective dimerization of alpha,beta-enones, providing a route for the asymmetric syntheses of chiral 1,5-dicarbonyl compounds and alpha-alkylated gamma-keto acids.