TETRAHEDRON: ASYMMETRY Tetrahedron: Asymmetry 14 (2003) 3081–3093 Pergamon TETRAHEDRON: ASYMMETRY REPORT NUMBER 61 Ionic liquids and chirality: opportunities and challenges Christine Baudequin, a Je ´rome Baudoux, a Jocelyne Levillain, b Dominique Cahard, a Annie-Claude Gaumont b, * and Jean-Christophe Plaquevent a, * a UMR 6014 de l’IRCOF (Institut de Recherche en Chimie Organique Fine), Universite ´ de Rouen, rue Tesnie `re, F -76821 Mont Saint Aignan Cedex, France b UMR 6507 Laboratoire de Chimie Mole ´culaire et Thioorganique, ENSICAEN-ISMRA, Universite ´ de Caen, 6 bd du Mare ´chal Juin, F -14050 Caen, France Received 26 June 2003; accepted 24 July 2003 Abstract—This review deals with recent advances in the investigation of ionic liquids (ILs) in the field of chirality, i.e. asymmetric synthesis and new chiral solvents. © 2003 Elsevier Ltd. All rights reserved. Contents 1. Introduction 3081 2. Asymmetric synthesis and catalysis in ILs 3082 2.1. Asymmetric synthesis in ILs 3082 2.1.1. Asymmetric aldol reactions 3082 2.1.2. Asymmetric allylation reactions 3083 2.1.3. Asymmetric Mannich type reaction 3083 2.1.4. Asymmetric fluorination reactions 3084 2.2. Asymmetric catalysis in ILs 3084 2.2.1. Asymmetric hydrogenation 3084 2.2.2. Asymmetric synthesis of cyanohydrins 3085 2.2.3. Asymmetric cyclopropanation 3086 2.2.4. Asymmetric allylic substitution 3086 2.2.5. Asymmetric ring-opening of epoxides 3086 2.2.6. Asymmetric epoxidation of alkenes 3087 2.2.7. Asymmetric dihydroxylation of alkenes 3087 3. Asymmetric biocatalysis in ILs 3087 4. Chiral ionic liquids: synthesis and applications 3089 5. Outlook 3091 References 3092 1. Introduction One of the main fields of interest for further studies in chemistry is the avoidance of toxic and environmentally unfriendly organic solvents. In this context, much attention has been devoted recently to the quest for novel reaction media. Ionic liquids (ILs), ion containing liquids, which combine good and tuneable solubility properties with a negligible vapor pressure and excellent thermal stabilities have rapidly found a place of choice as valuable substitutes for many volatile solvents. 1 The common classes of ILs comprise: alkylammonium salts, alkyl pyridinium salts and N,N -dialkyl imidazolium salts (Scheme 1). Numerous organic, 2 organometallic 2,3 and bio- catalyzed 3c,4 reactions have been performed with suc- cess in these new media. Owing to their unique properties, it soon became apparent that ILs are more * Corresponding authors. E-mail: jean-christophe.plaquevent@ univ-rouen.fr 0957-4166/$ - see front matter © 2003 Elsevier Ltd. All rights reserved. doi:10.1016/S0957-4166(03)00596-2