Solid-liquid phase transfer catalysis without solvent: an improvement for chiral Michael addition of N-acetylaminomalonate to chalcone

Abstract Solid-liquid phase transfer catalysis (PTC) without added solvent efficiently promotes chiral Michael addition when the reaction is achieved in presence of quaternary salts derived from (+) or (−) N-methyl ephedrine. Enantiomeric excesses are significantly increased by “omitting” the organic solvent during the reaction.