I. Introduction and Scope 3837 II. Oxidation Strategies 3838 III. Lewis Acids as Oxidation Catalysts 3839 A. Oxidations by Single Electron Abstraction 3839 B. Oxidations by an Assembly of Lewis Acid, Lewis Basic and Redox Centers 3841 1. Vanadium-Based Systems 3842 2. Metal Oxides Other than Vanadium 3844 C. Oxidations via Lewis Acid−Base Adducts 3847 1. Oxidations in Homogeneous Phase 3848 2. Oxidations in Biphasic Fluorous Systems 3854 3. Heteropolyacids as Oxidation Catalysts 3855 4.