Metal Cocatalyzed Tandem Alkynylative Cyclization Reaction of in Situ Formed N-Iminoisoquinolinium Ylides with Bromoalkynes via C-H Bond Activation

Silver triflate and copper(I) iodide cocatalyzed direct alkynylation and cyclization reaction of in situ formed N-iminoisoquinolinium ylides with bromoalkynes is described. The reaction proceeds efficiently through a combination of C-H activation and subsequent tandem reaction in one pot, leading to diverse H-pyrazolo[5,1-a]isoquinolines in good yields under mild reaction conditions.