Proton Abstraction Mechanism for the Palladium-Catalyzed Intramolecular Arylation

Abstract

Under the usual conditions, the Pd-catalyzed arylation does not involve an electrophilic aromatic substitution reaction. On the basis of DFT calculations, we propose a mechanism for the Pd-catalyzed arylation that involves a proton abstraction by a carbonate or related ligand and that provides a satisfactory explanation for the experimental data.

Mechanisms of C–H bond activation: rich synergy between computation and experiment

“…Echavarren, Maseras and co-workers reported an early combined experimental and theoretical study of such a process, where 10 reacted to give either 11 or 12, depending on the substituents, R (Scheme 3). 68 Their experimental studies suggest the key step to be a C-H activation in which the hydrogen from the phenyl is transferred as a proton, rather than via an electrophilic aromatic substitution mechanism.…”

Direct transition metal-catalyzed functionalization of heteroaromatic compounds

“…84 In this work, an ambident substrate 155 (Scheme 55), which can be intramolecularly arylated at both pyridine and benzene rings, was tested in the arylation reaction conditions. Notably, the reaction yielded regioisomer 156, resulting from arylation of the pyridine ring as the major product.…”

N-heterocyclic carbene tethered amido complexes of palladium and platinum

“…[1][2][3] Wide-ranging applications have been found for bifunctional catalysis, many in asymmetric synthesis, including hydrogenation under H 2 , 4 transfer hydrogenation, 5,6 isomerisation of allylic alcohols, 7 alkene hydroamination, 8 hydrosilylation, 9 Michael addition, 10 C-H activation [11][12][13][14][15] and lactide polymerisation. 16 The most studied of these reactions is the asymmetric transfer hydrogenation between alcohols and carbonyl compounds, catalysed by half-sandwich complexes of Ru, Ir or Rh with a chiral diamine ligand such as N-tosyl-1,2-diphenylethylenediamine.…”