Reductones

The present review on reductones encompasses principally literature which has appeared since the publication of Eistert and von Euler's basic monograph in 1957. The structure, analysis, preparation, and properties of reductones are discussed. Particular attention is paid to the aci-reductones some of which represent important natural products. 1. Structure and Tautomerism of Reductones 1.1. Chelate Structure of aci-Reductones 1.2. Problems in the Tautomerism of Reductones 2. Methods of Determination and Derivatives 2.1. Iodometric Titration 2.2. Tillmans' Reagent 2.3. Metal Chelates 2.4. Anils and Dianils 2.5. Oxidation of Reductones 3. Synthesis of Reductones 3.1. Reduction of Vicinal Triketones 3.2. Acetic Anhydride-Potassium Acetate Method 3.3. Hydrolysis-Isomerization of Trihaloketones and Halodiketones 3.4. Copper-Catalyzed Thermolysis of α-Diazo-β-diketones 3.5. Oxidative Isomerization of α,β-Epoxyaldehydes and -ketones 3.6. "α-Acylglycidic Ether Method" 3.7. Direct Introduction of an O-Function 3.8. Introduction of an O-Function by Oxidative Cleavage of a C-C Bond 3.9. Reductones Derived from Sugars 3.10. 1,4-Diketo Endiols 4. Most Important Reductones and their Characteristics