ABSTRACT
As a unique organofluorine fragment, gem-difluoromethylated motifs have received widespread attention. Here, a convenient and efficient synthesis of aryldifluoromethyl aryl ethers (ArCF2OAr') was established via Nickel-catalyzed aryloxydifluoromethylation with arylboronic acids. This approach features easily accessible starting materials, good tolerance of functionalities, and mild reaction conditions. Diverse late-stage difluoromethylation of many pharmaceuticals and natural products were readily realized. Notably, a new difluoromethylated PD-1/PD-L1 immune checkpoint inhibitor was conveniently synthesized and showed both improved metabolic stability and enhanced antitumor efficacy. Preliminary mechanistic studies suggested the involvement of a Ni(I/III) catalytic cycle.
