Fluorinated Alcohols: A New Medium for Selective and Clean Reaction

Abstract Owing to their unique properties (high hydrogen bonding donor ability, low nucleophilicity, high ionizing power and ability to solvate water), fluorinated alcohols, hexafluoroisopropanol (HFIP) and trifluoroethanol (TFE), modify the course of reactions when they are used as solvents, allowing reactions, which usually require the use of added reagents or metal catalysts to be carried out under neutral and mild conditions. New efficient and selective processes were developed for oxidation reactions, in particular with H 2 O 2 , oxirane ring-opening, and aza-Diels-Alder reactions without any catalyst. Products were easily isolated in high yields, and the fluoroalcohols could be directly recovered from the reaction medium and reused. These processes bring an improvement from an environmental point of view, by suppression of effluents, in particular heavy metals and are particularly simple, since most of the reactions do not require any work-up. 1 Introduction 2 Properties of Fluorinated Alcohols 3 Effect of HFIP in Oxidation Reactions 3.1 Activation of Hydrogen Peroxide 3.1.1 Selective Oxidation of Sulfides 3.1.2 Oxidation of Thiols to Disulfides 3.1.3 Epoxidation with Hydrogen Peroxide 3.1.4 Epoxidation with Dioxirane 4 Activation of Oxirane Ring Opening 4.1 Oxirane Ring Opening with Aromatic Amines 4.2 Oxirane Ring Opening with Thiols 4.3 Ring Opening of 1-CF 3 -Substituted Epoxy Ethers with ­Aromatic Amines 4.4 Ring Opening of 1-CF 3 -Substituted Epoxy Ethers with ­Carboxylic Acids 5 Cycloaddition Reactions of Imines 5.1 [4+2] Aza-Diels-Alder 5.2 Nucleophilic Addition/Aza-Diels-Alder Domino Reaction 6 Conclusion