Fast and mild palladium(ii)-catalyzed 1,4-oxidation of 1,3-dienes via activation of molecular oxygen with a designed cobalt(ii) porphyrin

Abstract

The use of a Co(porphyrin)-amide ligand, , in the palladium(II)-catalyzed 1,4-diacetoxylation of conjugated dienes under O2 results in aerobic oxidation. The catalyst was highly active under O2, and the 1,4-diacetoxylation reaction could also be performed under air.

Electrocatalytic Dioxygen Reduction by Carbon Electrodes Noncovalently Modified with Iron Porphyrin Complexes: Enhancements from a Single Proton Relay

“…The tetra(aryl)porphyrins were synthesized from benzaldehyde, the appropriate arylaldehyde, pyrrole, and aL ewis acid catalyst according to literature methods. [30] The spectroscopic properties matched those previously reported for aryl = phenyl, [31] 2-pyridyl, [32] 2-carboxylic acid, [33] and 2-hydroxyphenyl. [34] Porphyrins were metallated according to literature methods and the reaction progress was monitored by UV/Vis spectroscopy.…”

Open-air oxidative Heck reactions at room temperature

“…The oxidative Heck arylation differs from the more established palladium(0)-catalyzed Heck arylation [1][2][3] in the initial catalytic step, generating the essential arylpalladium intermediate by a transmetallation reaction instead of the usual oxidative addition process. Despite the need for smooth regeneration of palladium(II) after each catalytic turnover, [4][5][6] the increasing interest in these halide-free oxidative methodologies is illustrated by the large number of recent publications. [7][8][9][10][11] In this area, a number of miscellaneous transmetallation substrates have been investigated as suitable arylating agents, [7][8][9][10]12 although few can compete with arylboronic acids regarding stability, low toxicity and commercial availability.…”

Palladium(II) Catalyzed Cyclization-Carbonylation-Cyclization Coupling Reaction of (ortho-Alkynyl Phenyl) (Methoxymethyl) Sulfides Using Molecular Oxygen as the Terminal Oxidant

“…Bäckvall and coworkers have conducted extensive studies of the palladium(II)-mediated oxidative 1,4-addition of nucleophiles to conjugated dienes [7,8]. p-Benzoquinone is the most common stoichiometric oxidant used in these reactions, but Bäckvall and coworkers also developed a redox-coupled catalytic system to enable the use of molecular oxygen as the terminal oxidant for aerobic palladium-catalyzed oxidations [9][10][11].…”