Synthesis of gem-difluorinated pentacyclic indenopyrazolopyrazolones via Rh(iii)-catalyzed cascade C-H functionalization/[3+2] dipolar cycloaddition

By using gem-difluorocyclopropenyl acetates as versatile coupling partners, we realized Rh(iii)-catalyzed cascade C-H functionalization/[3 + 2] dipolar cycloaddition of azomethine imines, which delivered various gem-difluorinated pentacyclic indenopyrazolopyrazolone derivatives under mild reaction conditions with specific regio-/diastereo-selectivity and good functional group tolerance. A one-pot three-component reaction and preliminary enantioselective synthesis are also illustrated to further strengthen the potential use of the developed transformation.