Photocatalytic Carbon–Carbon σ‑Bond Anaerobic Oxidation of Ketones with Water by Rhodium(III) Porphyrins

Photocatalytic carbon–carbon σ-bond oxidation of unstrained ketones by water using rhodium­(III) porphyrin catalyst was accomplished. The catalysis yielded the corresponding one-carbon-less carbonyl compound and H₂ with up to 30 turnovers in both aliphatic and cyclic ketones with α substituents. No carbon loss was observed in aromatic ketone. Mechanistic studies suggest that (Ph₃P)­Rh^III(ttp)­OH (ttp = tetratolylporphyrinato dianion) is the key intermediate in the carbon–carbon σ-bond anaerobic oxidation

Room Temperature Catalyst System for the Hydroarylation of Olefins

A simple protocol for the hydroarylation of olefins to yield diarylmethine products is described. A Friedel–Crafts-type synthetic strategy allows direct access to biorelevant products in high atom efficiency. A combination of substoichiometric amounts of TMSCl and ZnBr₂ promotes a rapid hydroarylation process at ambient temperature. The method is high yielding and is amenable to scale-up protocols

Mild and Selective C(CO)–C(α) Bond Activation of Ketones with Rhodium(III) Porphyrin β‑Hydroxyethyl

Rhodium­(III) porphyrin β-hydroxyethyl, Rh^III(ttp)­CH₂CH₂OH (ttp = 5,10,15,20-tetratolylporphyrinato dianion), was found to serve as a precursor of the highly reactive Rh^III(ttp)­OH for the C­(CO)–C­(α) bond activation (CCA) of ketones under mild and aerobic conditions of 25–50 °C

Visible Light Photocatalysis of Carbon–Carbon σ‑Bond Anaerobic Oxidation of Ketones with Water by Cobalt(II) Porphyrins

Co^II(por) (por = porphyrinato dianion) reacted selectively with isopropyl ketones at the carbon (CO)–carbon (α) bond at room temperature to give high yields of Co^III(por) acyls and the corresponding oxidized carbonyl compounds in up to 89% yields. Co^III(por)­OH is proposed to be the C–C bond activation (CCA) intermediate. The stoichiometric reaction is further developed into the photocatalytic CCA using both UV and visible light sources (λ 405 nm). Under ambient conditions, the photocatalytic C–C oxidation of 2,6-dimethylcyclohexanone gives 2-heptanone in up to 24 turnovers in the presence of isopropyl alcohol as the H atom donor and H₂O as the oxidant. Various isopropyl ketones successfully undergo photocatalysis