Cross-coupling by a noncanonical mechanism involving the addition of aryl halide to Cu(II)

• 成果类型: Article
• 署名作者: Delaney, Connor P.; Lin, Eva; Huang, Qinan; Yu, Isaac F.; Rao, Guodong; Tao, Lizhi; Jed, Ana; Fantasia, Serena M.; Puentener, Kurt A.; Britt, R. David; Hartwig, John F.
• 署名单位: University of California System; University of California Berkeley; University of California System; University of California Davis; Roche Holding; University of California System; University of California Berkeley
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-10042
• DOI: 10.1126/science.adi9226
• 发表日期: 2023-09-08
• 页码: 1079-+
• 关键词: (hetero)aryl chlorides; copper-complexes; amination; ligands; chemistry; path

摘要

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.