Hydrogen‐Bonding Interactions in the Ley–Griffith Oxidation: Practical Considerations for the Synthetic Chemist

Abstract

The Ley–Griffith oxidation, which is catalyzed by tetra‐n‐propylammonium perruthenate (TPAP, nPr4N[RuO4]), is a popular method for not only controlled oxidation of primary alcohols to aldehydes, but also a host of other synthetically useful transformations. While the fundamental reaction mechanism has recently been elucidated, several key hydrogen‐bonding interactions between the reagents were implicated but not investigated. Herein the prevalence of H‐bonding between the co‐oxidant N‐methylmorpholine N‐oxide (NMO), the alcohol substrate, water and the perruthenate catalyst is established. These observations help to rationalize the importance of drying the reagents and lead to several practical suggestions.

Synthesis and Structures of Ruthenium Carbonyl Complexes Bearing Pyridine-Alkoxide Ligands and Their Catalytic Activity in Alcohol Oxidation

“…It is well-known that transition metal complexes play a crucial role in oxidation process. Many transition metal catalysts including ruthenium (Shapley et al, 2000; Lybaert et al, 2017; Sarbajna et al, 2017; Moore et al, 2019), palladium (Stahl, 2004; Sigman and Jensen, 2006; Ho et al, 2018), copper (Velusamy et al, 2006; Jehdaramarn et al, 2018; Lagerspets et al, 2019), and iron (Coleman et al, 2010; Stanje et al, 2018) have been reported for promoting the oxidation of alcohols. Among them, ruthenium compounds are intensively studied because of their rich structures and various valence states.…”

Two Simple and Highly Efficient Variants of the Griffith‐Ley Oxidation of Alcohols

“…[5] In contrast to this, high reaction states were postulated in the literature to drive the Griffith-Lay oxidation. [2,6] In course of a study on the oxidation of alcohols from natural resources, we were looking for catalyst systems giving optimum yields and selectivities in the dehydrogenation of alcohols to aldehydes and ketones in the presence of a reasonably priced oxidizing agent. We therefore revived the protocol of Sharpless and co-workers under these basic conditions.…”