Regioselective Synthesis of Pyrazole Triflones Based on Triflyl Alkyne Cycloadditions

The regioselective synthesis of pyrazole triflones has been achieved by 1,3-dipolar cycloaddition of triflyl alkynes and hydrazonoyl chloride in the presence of Hunig's base. Pyrazolo[5,1-a]isoquinoline triflones were also regioselectively synthesized for the first time via tandem 1,3-dipolar cycloaddition/oxidative aromatization between triflyl alkynes and C,N-cyclic azomethine imines.