Transition Metal Catalysis in Aerobic Alcohol Oxidation
CHAPTER 9: Asymmetric Oxidation of Alcohols and Phenol Derivatives with Air as Oxidant
Published:21 Oct 2014
Transition metal catalysis is a cornerstone of modern asymmetric synthesis. Recently, late transition metal complexes have attracted increasing attention because of their unique redox properties in aerobic oxidation catalysis. Among them, ruthenium, iridium and iron complexes have been found to serve as efficient catalysts for the asymmetric oxidation of aliphatic and aromatic hydroxy compounds using dioxygen in air as an oxidant, to afford optically active organic substances such as alcohols, esters, symmetric and non-symmetric 1,1′-biarenols, and cyclic α,β-unsaturated ketones. The use of dioxygen that is ubiquitous in air renders these oxidation reactions green and practical, because it is highly atom efficient and available without energy consumption for transport. In this chapter, enantioselective oxidative transformations, including kinetic resolution of secondary alcohols, desymmetrization of meso-diols, asymmetric coupling and dearomatization of aromatic hydroxy compounds, which use ruthenium, iridium and iron complexes as catalysts and air as oxidant, are described.