Cerium(IV) Ammonium Nitrate: A Versatile Oxidant in Synthetic Organic Chemistry

Introduction

Among the various cerium(IV) complexes, cerium(IV) ammonium nitrate (CAN) is one of the most important oxidants in organic synthesis, as it is sufficiently stable in different solvents and is commercially available. It is useful for introducing and removing protecting groups via single-electron transfer or Lewis acid catalysis. [1] CAN serves as a convenient reagent for the generation of radicals from CH-acidic substrates, [2] exhibiting a similar reactivity pattern (+1.61 V vs. NHE) as Mn(III) acetate (+1.51 V vs. NHE). Recently, CAN has been utilized for many synthetic transformations such as debenzylation, [3] oxidation, [4] oxidative free-radical reactions in green media such as water [5] and ionic liquids, [6] carbon-carbon bond formation [7] and halogenation. [8] This reagent has been reviewed [9] for reactions involving carbon-nitrogen, carbon-sulfur, carbon-selenium, and carbon-halogen bond formations. In addition, this reagent is used in the one-pot synthesis of various heterocycles including dihydrofurans, tetrahydrofurans and aminotetralins. [10]

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