Palladium-free Wacker-inspired oxidation: challenges and opportunities in catalysis

Abstract

Palladium-catalysed Wacker-type oxidation of olefins to ketones or aldehydes is one of the most prominent homogeneous reactions globally, even performed at a multi-tonne scale. From a fundamental and from an applied point of view, it is extremelly appealing to replace palladium catalysts by other metal-based catalysts to increase the levels of efficiency, selectivity and sustainability, particularly looking at the reactivity of welldefined first-row transition metal complexes as catalysts. In this case, the role of the ligand(s) coordinating to the metal(s) play a major role to control selectivity and activity thanks to unique mechanistic considerations. This mechanistically-driven feature article emphasizes the advantages and disadvantages of current existing approaches. Besides main efforts devoted to homogeneous catalysis, heterogenous systems and biocatalysis have also been studied as they offer complementary strategies. This contribution overall presents an up-todate analysis of key contributions while highlighting missing gaps for future developments in this important and exciting field..