Silver trifluoroacetate as a bifunctional reagent for palladium-catalyzed oxidative carbonylative [4 + 1] annulation of aromatic acids

AgTFA is disclosed as a bifunctional reagent, i.e. unprecedented in-situ CO source and oxidant in oxidative carbonylative annulation. The simple operation enables silver to be recovered easily and make AgTFA superior to other transition-metal carbonyl agents.