Anion-Binding Catalysis

3(Thio)urea and Squaramide‐Catalyzed Anion‐Binding Catalysis with Halogen Anions

Matthew A. Horwitz and Véronique Gouverneur

University of Oxford, Department of Chemistry, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK

3.1 Introduction

The synthetic possibilities offered by anion‐binding catalysis with halogen anions have grown exponentially since the advent of this research area [1–4]. The conceptual evolution of this line of research began with the development of catalytic asymmetric methods that relied on noncovalent interactions between organocatalysts and electrophiles. In this regard, this chapter details the establishment of the accepted S_N1‐type mechanism that has been proposed in many systems, whereby the catalyst ...