An unexpected three-component reaction of 2-alkylenecyclobutanone and N′-(2-alkynylbenzylidene)hydrazide with water

Abstract

The generation of 3-(pyrazolo[5,1-a]isoquinolin-1-yl)propanoic acids via a silver(I)-catalyzed three-component reaction of 2-alkylenecyclobutanone and N′-(2-alkynylbenzylidene)hydrazide with water is reported. This unexpected transformation proceeds through 6-endo cyclization, [3 + 2] cycloaddition, and rearrangement, leading to 3-(pyrazolo[5,1-a]isoquinolin-1-yl)propanoic acids in good yields.