Copper(I) Phenoxide Complexes in the Etherification of Aryl Halides

Abstract

Was ist der richtige Weg? Kupfer(I)‐Phenoxid‐Komplexe mit Chelatliganden (siehe Bild) sind mögliche Intermediate bei Kupfer‐katalysierten Veretherungen von Arylhalogeniden. Sie wurden nun synthetisiert und vollständig charakterisiert. Es wurde demonstriert, dass die isolierten Komplexe in kinetischer und chemischer Hinsicht plausible Zwischenstufen bei der Synthese von Arylphenylethern sind. Ein Verlauf über Radikale wurde experimentell ausgeschlossen.

Understanding the Heteroatom Effect on the Ullmann Copper-Catalyzed Cross-Coupling of X-Arylation (X = NH, O, S) Mechanism

“…The Gibbs energies computed for the formation of the complexes [(phen)Cu I (XPh)] follow the trend according to the pK a of the nucleophiles, i.e., pK a (PhNH 2 ) = 27.0, pK a (PhOH) = 9.95, and pK a (PhSH) = 6.5. In concordance with the experiments outcomes [60,65] [66,67], Chen et al [42], and Zhang et al [59][60][61]. Our results show that this disproportionation is unfavorable in nonpolar solvents while it becomes favored when the dipolar constant of the solvent increases, in good agreement with previously reported results [59][60][61].…”

A Broadly Applicable Copper Reagent for Trifluoromethylations and Perfluoroalkylations of Aryl Iodides and Bromides

“…[22,23] Thus, if the trifluoromethylation occurs through an aryl radical, then cyclized product 7 should be observed (Scheme 9). [9b,c] Instead, the trifluoromethylarene 4cc was obtained in 91% yield, and cyclized product 7 was not detected by GC/MS analysis. This result implies that the copper-mediated trifluoromethylation reaction proceeds without the intermediacy of an aryl radical from electron transfer and expulsion of iodide.…”

A Broadly Applicable Copper Reagent for Trifluoromethylations and Perfluoroalkylations of Aryl Iodides and Bromides

“…As part of our studies on the structures and reactions of isolated copper complexes that are potential intermediates in cross-coupling reactions, [9] we sought to determine the structure and stability of the proposed [(phen)CuCF 3 ] (1) and to determine the relative reactivity of this complex as a discrete species toward electron-poor and electron-rich iodoarenes. We report two routes to form [(phen)CuCF 3 ] (1) and its higher perfluoroalkyl homologue [(phen)-CuCF 2 CF 2 CF 3 ] (2) in high yield, one route that forms these two complexes as pure, isolated species and one that forms them in high yield in DMF.…”