Mechanistic Aspects of Submol % Copper‐Catalyzed CN Cross‐Coupling

Abstract

Carbonnitrogen bond formation can be catalyzed by copper in very low concentrations (≈100 ppm), with mechanistic features that are distinct from those in the high‐concentration regime. The reaction was studied by initial rate kinetics, competitive Hammett studies, and DFT calculations. The deprotonation of the model nucleophile, pyrrole, is limited by mass transfer with the heterogeneous base. The positive reaction order in dimethylethylenediamine was explained by this reagent working not only as a ligand to Cu, but also as a facilitator for mass transfer. The selectivity‐determining step in the competitive Hammett study is oxidative addition. Alternative mechanisms for this step, such as single‐electron transfer, atom transfer, or σ‐bond metathesis, can be excluded based on the observed Hammett behavior and DFT calculations.

Mechanistic Studies of Ullmann‐Type C–N Coupling Reactions: Carbonate‐Ligated Copper(III) Intermediates

“…Recently, a similar negative effect of HPO 4 2− was reported by Lu and co‐workers in Ni‐mediated reactions . In this situation, a greater amount of ligand or nucleophile is required to generate the active species ( 3 b / 3 c ) and for mass transfer ( 6 is insoluble in toluene).…”

Activation of Copper Species on Carbon Nitride for Enhanced Activity in the Arylation of Amines

“…In situ formation of the active species. The mechanism of CuI-catalyzed reaction in homogeneous phase has been both experimentally 58 and computationally [59][60][61] studied in the literature. Our study has shown that a two-fold enhancement in activity can be achieved by introducing metal-free GCN material and that nearly quantitative yields can be obtained after 4 h through doping the lattice of GCN with Fe single atoms.…”

Synthesis of 1‐Vinyl/Arylbenzotriazole 3‐Oxides through a Copper‐Mediated C–N Bond Coupling Reaction

“…The O‐ or N‐arylation mechanism via the copper‐catalyzed coupling reaction has been studied by the Stahl, Norrby, and Das groups by use of density functional theory (DFT) calculations. The reaction involves transmetallation, binding, deprotonation, oxidation, and reductive elimination steps.…”