Synthesis of aryldifluoromethyl aryl ethers via nickel-catalyzed suzuki cross-coupling between aryloxydifluoromethyl bromides and boronic acids

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. Aryldifluoromethyl aryl ethers (ArCF2OAr') are powerful structural motifs to improve druggability, however, their targeted synthesis remains challenging. Here, the authors report the efficient synthesis of ArCF2OAr' motifs via nickel-catalyzed aryloxydifluoromethylation with arylboronic acids, and their application in the total synthesis of a difluoromethylated PD-1/PD-L1 immune checkpoint inhibitor with enhanced antitumor efficacy over the non-fluoro congener.

Automated summary

A convenient and efficient synthesis of aryldifluoromethyl aryl ethers (ArCF2OAr') was achieved via Nickel-catalyzed aryloxydifluoromethylation with arylboronic acids. This method offers easily accessible starting materials, good tolerance of functionalities, and mild reaction conditions. The synthesized compounds were successfully applied in the total synthesis of a difluoromethylated PD-1/PD-L1 immune checkpoint inhibitor with improved metabolic stability and enhanced antitumor efficacy.