Design and Application of Chiral Hydrogen Bond Donors for Enantioselective Catalysis

ABSTRACT: The bare hydrogen atom, a proton, functioning in the Brønsted-Lowry sense, is perhaps the oldest catalyst used to promote chemical reactions. In contrast, the Lewis acid property of a hydrogen atom bonded to an electronegative atom, most evident in hydrogen bonds, remained little utilized for catalysis. Indeed, for asymmetric catalysis, the concept of Lewis acid catalysis became synonymous with metal-based catalysis. Hydrogen bonds, while of central importance for biomolecules, played until recently a minor role in the promotion of chemical reactions. This situation changed dramatically about ten years ago, with reports of small hydrogen bond donor molecules that functioned as effective catalysts for enantioselective reactions. In this presentation, I will describe some of the results that have come out of my lab within this rapidly evolving field of catalysis.