Silver triflate–copper(ii) acetate cooperative catalysis in a cascade reaction for concise synthesis of 2-carbonyl H-pyrazolo[5,1-a]isoquinolines

A cascade reaction of N'-(2-alkynylbenzylidene)hydrazide with allenoate in the presence of dioxygen co-catalyzed by silver triflate and copper(II) acetate under mild conditions is described, which provides an efficient approach to 2-carbonyl H-pyrazolo[5,1-a]isoquinolines.