N-Selective Difluoromethylation of 4-Hydroxyquinolines

N-selective difluoromethylation of 4-hydroxyquinolines is a formidable challenge due to competing N- and O-difluoromethylation pathways. Herein, we present a mild, efficient, and scalable protocol using BrCF₂CO₂H and LiO^tBu for the selective N-difluoromethylation of 4-hydroxyquinolines. This method tolerates reactive functional groups such as carboxylic acid, ester, and amide. A series of N-deuterodifluoromethyl analogues (−CF₂D) is also synthesized.