Mechanism of the catalytic carbonylation of aryl halides with a modified cobalt carbonyl

Chemoselectivity of cobalt-catalysed carbonylation—A reliable platform for the synthesis of fluorinated benzoic acids

“…This reaction can proceed in several different ways, two of which are potentially relevant in this system: the classic S N Ar mechanism (via intermediate formation of a Meisenheimer complex) or the radical-anion nucleophilic substitution (S RN 1) involving the electron transfer from the cobalt anionic complex to the aryl halide. We have demonstrated [13] the definite evidence in favor of the S RN 1 mechanism. The chemoselectivity data of fluorinated aryl halide carbonylation could answer the question of actual mechanism of this interaction.…”

“…Alongside with the others, we have studied the reaction of the aryl halide carbonylation catalysed by a modified cobalt carbonyl complex (Scheme 1) [11][12][13][14].…”

“…The key stage of carbonylation process is the reaction between an aryl halide and an anionic cobalt complex leading to the formation of an aryl cobalt complex in the reaction of nucleophilic substitution [13]. This reaction can proceed in several different ways, two of which are potentially relevant in this system: the classic S N Ar mechanism (via intermediate formation of a Meisenheimer complex) or the radical-anion nucleophilic substitution (S RN 1) involving the electron transfer from the cobalt anionic complex to the aryl halide.…”

“…The reaction occurs in the presence of tetracarbonylcobaltate anion and corresponds to the S N 2 mechanism [1][2][3][4]. The activation of aryl halides requires special techniques, including the UV irradiation, the system enrichment with a one-electron reducing agent, or the modification of the Co(CO) 4 À anion [5][6][7][8][9][10][11][12][13][14]. All these early studies demonstrate the ability of the Co(CO) 4 À anion to be an efficient catalyst for the carbonylation of aryl halides in conditions that provide the anion-radical synthetic pathway.…”

Cobalt-Catalyzed Methoxycarbonylation of Substituted Dichlorobenzenes as an Example of a Facile Radical Anion Nucleophilic Substitution in Chloroarenes

“…The reaction of aryl halide methoxycarbonylation catalysed with alkyl cobalt carbonyl complexes (Scheme 1) provides an interesting model to study the principles of the radical anion transformations in aryl halides [16,17,18,19,20,21,22,23].…”