Aerobic Copper‐Catalyzed Salicylaldehydic Cformyl−H Arylations with Arylboronic Acids

• Published in: Chemistry : a European journal 2021-02, Vol.27 (10), p.3278-3283
• Main Authors: Xiao, Lin, Lang, Tao‐Tao, Jiang, Ying, Zang, Zhong‐Lin, Zhou, Cheng‐He, Cai, Gui‐Xin
• Format: Article
• Language: English
• Subjects: Acids; Carbazole; Carbazoles; Catalysis; Chemistry; chemoselectivity; Coordination compounds; Copper; copper catalysis; Copper compounds; C−C coupling; C−H activation; Estrone; Hydrogen bonds; Phenolic compounds; Phenols; salicylaldehydes; Substrates
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.202004810

We report a challenging copper‐catalyzed Cformyl−H arylation of salicylaldehydes with arylboronic acids that involves unique salicylaldehydic copper species that differ from reported salicylaldehydic rhodacycles and palladacycles. This protocol has high chemoselectivity for the Cformyl−H bond compared to the phenolic O−H bond involving copper catalysis under high reaction temperatures. This approach is compatible with a wide range of salicylaldehyde and arylboronic acid substrates, including estrone and carbazole derivatives, which leads to the corresponding arylation products. Mechanistic studies show that the 2‐hydroxy group of the salicylaldehyde substrate triggers the formation of salicylaldehydic copper complexes through a CuI/CuII/CuIII catalytic cycle. A challenging copper‐catalyzed Cformyl−H arylation of salicylaldehydes with arylboronic acids has been developed. It involves unique salicylaldehydic copper species that differ from reported salicylaldehydic rhodacycles and palladacycles, as well as high chemoselectivity for Cformyl−H bond compared to the phenolic O−H bond based on copper catalysis.