Synthetic models of 2-oxoglutarate-dependent oxygenases

The 2-oxoglutarate (2OG)-dependent oxygenases utilize dioxygen and 2OG to oxidize a wide variety of substrates. Over the past two decades, a number of Fe(ii)-containing model systems of structural relevance to 2OG-dependent enzymes utilizing tripodal ligand frameworks and 2-oxo acids have provided great insight into the reactivity of these enzymes. Like the 2OG-dependent enzymes, the model complexes react with dioxygen and carry out the oxidative decarboxylation of a 2-oxoacid to generate a potent oxidant that is likely to be an Fe(iv)O intermediate. Over the past 12 years, many Fe(iv)O complexes have been synthesized, spanning a variety of ligand motifs, coordination geometries and spin states. This chapter reviews the synthetic strategies applied to generating both functional models of the reactions carried out by 2OG-dependent enzymes, as well as spectroscopic models of relevance to transient reaction intermediates. A focus is given to advances in understanding of the enzymatic reaction obtained from studying the reactivity of these synthetic systems.