Clay-Supported Copper(II) and Iron(III) Nitrates: Novel Multi-Purpose Reagents for Organic Synthesis

Abstract

Partial dehydration in acetone activates iron(III) or copper(II) nitrate. These activated nitrato complexes, with covalent metal-ligand bonds, are stabilized in a convenient form by impregnation upon a modified montmorillonite clay (K10). These mild and inexpensive reagents offer versatile applications to organic synthesis. As sources of nitrosonium cations (NO⁺), they perform a number of useful functional group interconversions. They effect also the regioselective mononitration of phenols. 1. Introduction 2. Rational Design of the Clayfen and Claycop Reagents 3. The Reagents 4. Oxidation of Alcohols 5. Oxidative Coupling of Thiols 6. Comments on the Unique Characteristics of the Nitrosonium Ion (NO⁺) 7. Carbonyl Group Deprotections 8. Synthesis of Azides and Iminophosphoranes 9. Aromatization of 1,4-Dihydropyridines 10. Regioselective Nitration of Phenols 11. Other Applications and Prospects 12. Addendum