Biologically inspired nonheme iron complex-catalyzed cis-dihydroxylation of alkenes modeling Rieske dioxygenases

The development of selective catalytic oxidation systems for alkene cis-dihydroxylation under environmentally benign conditions is an important goal that has long been pursued in the fields of synthetic and biomimetic chemistry and catalysis. Excellent examples for cis-dihydroxylation of alkenes are naturally occurring nonheme iron-dependent Rieske dioxygenases capable of performing aerobic regio- and stereoselective cis-dihydroxylation that is involved in the degradation of aromatics, with both oxygen atoms of O₂ incorporated into the cis-dihydrodiol product. Inspired by the structural features of the nonheme iron enzyme center and the reaction mechanisms that underlie their efficacy to catalyze cis-dihydroxylation utilizing O₂ and NADH as co-substrates, numerous nonheme iron complexes have been designed as the functional models of Rieske dioxygenases and demonstrated that those nonheme iron models catalyze the cis-dihydroxylation of alkenes with H₂O₂ as a terminal oxidant, yielding the cis-dihydrodiol products selectively. In this review, we describe recent developments of biologically inspired nonheme iron complexes for cis-dihydroxylation catalysis together with the evolution of the postulated reaction mechanisms to rationalize the experimental observations and the dichotomy between alkene cis-dihydroxylation and epoxidation, with particular emphasis on the structure–reactivity correlation of catalysts. These studies would provide important insights into the fundamental reaction pathways in enzymatic reactions and contribute to the rational design of efficient and selective bioinspired cis-dihydroxylation catalysts.