μ-Oxo-bis[(octacosafluoro-meso-tetraphenylporphyrinato)iron(iii)] - synthesis, crystal structure, and catalytic activity in oxidation reactions

Markovnikov-Selective Cobalt-Catalyzed Wacker-Type Oxidation of Styrenes into Ketones under Ambient Conditions Enabled by Hydrogen Bonding

The replacement of palladium catalysts for Wacker-type oxidation of olefins into ketones by first-row transition metals is a relevant approach for searching more sustainable protocols. Besides highly sophisticated iron catalysts, all the other first-row transition metal complexes have only led to poor activities and selectivities. Herein, we show that the cobalt-tetraphenylporphyrin complex is a competent catalyst for the aerobic oxidation of styrenes into ketones with silanes as the hydrogen sources. Remarkably, under room temperature and air atmosphere, the reactions were exceedingly fast (up to 10 minutes) with a low catalyst loading (1 mol %) while keeping an excellent chemo- and Markovnikov-selectivity (up to 99 % of ketone). Unprecedently high TOF (864 h-1 ) and TON (5,800) were reached for the oxidation of aromatic olefins under these benign conditions. Mechanistic studies suggest a reaction mechanism similar to the Mukaiyama-type hydration of olefins with a change in the last fundamental step, which controls the chemoselectivity, thanks to a unique hydrogen bonding network between the ethanol solvent and the cobalt peroxo intermediate.

Recent advances in iron-catalysed coupling reactions for the construction of the C(sp2)-C(sp2) bond

The advancement of transition-metal-catalyzed coupling reactions has been demonstrated as a highly effective strategy for the formation of carbon-carbon bonds, which serve as the fundamental basis for organic synthetic chemistry. Given that iron represents one of the most economical and ecologically sustainable metallic elements available, the exploration and enhancement of iron-catalysed coupling reactions have garnered increasing interest within the scientific community. In recent years, numerous iron-catalysed reactions have been reported, showcasing their efficacy in establishing C-C bonds. In this minireview, we present a systematic analysis of C(sp²)-C(sp²) bond formation via iron-catalysed coupling reactions as documented in the extant literature.