Synthesis of Fluorine-Containing 6-Arylpurine Derivatives via Cp*Co(III)-Catalyzed C-H Bond Activation.

CpCo(III)-catalyzed (Cp=pentamethylcyclopentadienyl) C-H bond functionalization of 6-arylpurines using gem-difluoroalkenes and allyl fluorides is described. The reaction with gem-difluoroalkenes afforded monofluoroalkenes with high (Z)-selectivity, while the reaction with allyl fluorides led to C-H allylation in moderate (Z)-selectivity. Both reactions proceeded using a user-friendly single-component catalyst Cp*Co(CHCN) in fluorinated alcohol solvents without any additives. Robustness was also demonstrated by a preparative-scale reaction under air.