Assisted by Hydrogen-Bond Donors: Cinchona Quaternary Salts as Privileged Chiral Catalysts for Phase-Transfer Reactions

Abstract

AbstractThis short review is devoted to asymmetric phase-transfer reactions that employ hybrid ammonium Cinchona catalysts supported by possessing hydrogen-bond donor groups. We present recent advances utilizing this type of catalyst in the field of biphasic reaction systems. The main emphasis is placed on the advantages of additional functional groups present in the structure of the catalyst, such as hydroxy, amide, (thio)urea or squaramide.1 Introduction2 Phase-Transfer Hybrid Cinchona Catalysts with a Free Hydroxy Group3 (Thio)urea Hybrid Cinchona Catalysts4 Hybrid Amide-Based Catalysts Bearing a Cinchona Scaffold5 Conclusions