Catalytic Aerobic Oxidations
CHAPTER 2: Aerobic Oxidation Reactions Using Metal-based Homogeneous Systems
Published:14 Jul 2020
Molecular oxygen is the reagent of choice for many organic reactions, including the oxidation of a variety of substrates. The importance of carbonyl and carboxylic compounds has boosted research on alternative approaches based on more sustainable reagents. To this end, aerobic oxidative approaches have emerged as a promising option to other entries involving Friedel-–Crafts acylation, Claisen condensation, esterification or amidation reactions. In comparison with the use of heterogeneous catalysts and organocatalysts, homogeneous catalysts provide considerably higher substrate : catalyst ratios and selectivities. This chapter summarizes the most remarkable reports on the use of homogeneous catalysts for the molecular oxygen-mediated oxidation of alcohols, active methylene compounds and oxidative cleavage of unsaturated hydrocarbons, with a focus on palladium, copper and ruthenium catalysts. Special attention will be paid to aspects such as catalyst amounts, the need for co-catalysts, the pressure of oxygen or air required and reaction media.