Co-Catalyzed atom transfer radical addition of bromodifluoroacetamides, expanding the scope of radical difluoroalkylation.

The atom transfer radical addition (ATRA) of bromodifluoroacetamides to arylalkynes and terminal alkenes was conducted using von Wangelin's Co catalyst system (CoBr2/1,2-bis(diphenylphosphino)benzene/Zn) in acetone/H2O at 30 °C to afford the corresponding functionalized difluoroacetamides in 33-89% yields. Moreover, the Co catalyst was successfully applied to the tandem addition/cyclization of 1,6-diene and -enyne substrates and intramolecular ATRA of N-allyl and N-propargyl bromodifluoroacetamides, significantly expanding the scope of radical difluoroalkylation.

Synthesis of difluoromethylated diarylmethanes via Fe(OTf)3-catalyzed Friedel-Crafts reaction of 2,2-difluoro-1-arylethyl phosphates.

The Fe(OTf)3-catalyzed Friedel-Crafts reaction of 2,2-difluoro-1-arylethyl phosphates with electron-rich (hetero)arenes afforded difluoromethylated diarylmethanes. Control experiments showed that Fe(OTf)3 behaves as the Lewis acid, and that the phosphate leaving group and o- or p-alkoxy substituents on the substrates are necessary for the Fe(OTf)3-catalyzed reaction to proceed under mild conditions.