Selective Oxidations by Peroxide-Based Reagents

Combination of α-siloxyalkyl peroxybenzoates with a catalytic amount of transition metal salts exhibited mono-oxygen transfer abilities. Their oxidizing abilities are strongly dependent on the nature of the metal salts used. Fe³⁺ was a powerful catalyst for alkane oxidation, whereas Cu²⁺ effected olefin epoxidation. α-Siloxyalkyl hydroperoxide could be attached to organic substrates through a peroxy ester linkage. Upon exposure of such peroxy esters to an appropriate metal salt, regioselective oxidation of the substrates was accomplished in an intramolecular fashion. By using anhydrous ethereal hydrogen peroxide, biologically important hydroperoxides such as a thymidine 4′-hydroperoxide analog and 12-hydroperoxyicosatetraenoic acid ester were prepared. Photolysis of N-2-hydroperoxyalkylphthalimides generated free hydroxyl radical effectively. The "photo-Fenton-reagent" was utilized as an efficient DNA cleaving agent. 1. Introduction 2. Remote Oxidation for Site-Selective Functionalization 2.1. Concept 2.2. Selective Hydrocarbon Oxidation by α-Siloxyalkyl Peroxy Ester-Iron(III) Perchlorate 2.3. Epoxidation of Olefins by α-Siloxyalkyl Peroxy Ester-Copper(II) Trifluoroacetate 2.4. Palladium(II)-Catalyzed Oxidation by α-Siloxyalkyl Peroxybenzoate 3. Selective Synthesis of Biologically Important Hydroperoxides 3.1. Synthesis and Chemistry of a Thymidine 4′-Hydroperoxide Analog 3.2. Synthesis of Hydroperoxyicosatetraenoic Acid (HPETE) 4. Photo-Induced Hydroxyl Radical Generation from N-2-Hydroperoxyalkylphthalimide 5. Conclusion