Cleavage of ethers

Abstract

The scope and limitations of reagents for the cleavage of ethers are discussed. The reagents are conveniently classified in the five main headings. Selectivity patterns of some of the reagents are discussed in cases where sufficient data has been given in the literature. 1. Introduction 2. Acidic Reagents 2.1. Bronsted Acids 2.2. Lewis Acids 3. Basic Reagents 3.1. Alkali Hydroxides 3.2. Alkali Alkoxides 3.3. Alkali Amides 3.4. Alkali Metals 3.5. Organo-Alkali Metal Compounds 3.6. Sodium Cyanide/Dimethyl Sulfoxide 3.7. Sodium Ethanethiolate 3.8. Sodium Thiocresolate 3.9. Lithium Iodide 3.10. Sodium Benzeneselenolate 4. Miscellaneous Reagents 4.1. Iodotrimethylsilane 4.2. Iodotrichlorosilane 4.3. Dichloroiodomethylsilane 4.4. Bromotrimethylsilane 4.5. Alkylthiotrimethylsilanes 4.6. Ethanethiol or Ethanedithiol/Boron Trifluoride Etherate 4.7. Aluminium Halide/Thiol Systems 4.8. Acetyl Iodide and Pivaloyl Iodide 4.9. Diiodomethyl Ether/Hydrogen Iodide 5. Reductive Cleavage of Ethers 5.1. Lithium Tris[t-butoxy]aluminium Hydride/Triethylborane Complex 5.2. Hydrogenolysis 6. Oxidative Cleavage of Ethers 6.1. Ceric Ammonium Nitrate 6.2. Silver Oxide 6.3. Dichlorodicyanoquinone 6.4. Tris[p-bromophenyl]ammonium Hexachloroantimonate 7. Photochemical Cleavage of Ethers 8. Selectivity in Ether Cleavage 8.1. Stereoelectronic Characteristics of the Ether-Cleaving Agent 8.2. Structural Features of the Groups Cleaved 8.3. Molecular Environment of the C-O Bond not Undergoing Cleavage 9. Addendum