Silver-catalyzed C-3 arylthiodifluoromethylation and aryloxydifluoromethylation of coumarins

A facile silver-catalyzed oxidative decarboxylation of arylthiodifluoroacetic acids or aryloxydifluoroacetic acids with coumarins/quinoxalin-2(1H)-ones was developed. This transformation provided a series of C-3 aryloxydifluoromethylated or arylthiodifluoromethylated coumarins/quinoxalin-2(1H)-ones containing various functional groups in moderate to good yields, featuring good functional group tolerance, easily accessible starting materials and operational simplicity.