Metal-catalyzed biomimetic aerobic oxidation of organic substrates

The use of molecular oxygen (O2) as terminal oxidant in transition metal-catalyzed oxidative reactions is an appealing and challenging approach in organic chemistry. In these oxidations, the reoxidation of the reduced form of the metal catalyst by O2 is the key and challenging step, due to the triplet ground state of O2 and the high energy barrier for electron transfer. Inspired by (i) the electron transfer chain (ETC) in aerobic respiration and (ii) metalloenzymes for oxidations in Nature, organic chemists have developed metal-catalyzed biomimetic oxidations. In this chapter, two biomimetic approaches for transition metal-catalyzed aerobic oxidations are summarized, including: (i) biomimetic oxidation by multistep electron transfer pathways inspired by the respiratory chain and (ii) biomimetic oxidation by rational design of metal complexes that mimic metalloenzymes. The first type of aerobic oxidative transformations discussed include Wacker oxidations, alkyne oxidations, CH functionalizations, and dehydrogenative oxidations of alcohols and amines. The second type of aerobic oxidations include iron-, copper- and manganese- osmium- and vanadium-catalyzed reactions.