Cross-coupling by a noncanonical mechanism involving the addition of aryl halide to Cu(II).
Science
; 381(6662): 1079-1085, 2023 Sep 08.
Article
in En
| MEDLINE
| ID: mdl-37676958
Copper complexes are widely used in the synthesis of fine chemicals and materials to catalyze couplings of heteroatom nucleophiles with aryl halides. We show that cross-couplings catalyzed by some of the most active catalysts occur by a mechanism not previously considered. Copper(II) [Cu(II)] complexes of oxalamide ligands catalyze Ullmann coupling to form the C-O bond in aryl ethers by concerted oxidative addition of an aryl halide to Cu(II) to form a high-valent species that is stabilized by radical character on the oxalamide ligand. This mechanism diverges from those involving Cu(I) and Cu(III) intermediates that have been posited for other Ullmann-type couplings. The stability of the Cu(II) state leads to high turnover numbers, >1000 for the coupling of phenoxide with aryl chloride electrophiles, as well as an ability to run the reactions in air.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Science
Year:
2023
Document type:
Article
Affiliation country:
United States
Country of publication:
United States