Gold catalyzed [3+2] cycloaddition of N-allenyl amides with azomethine imines

Gold(I) catalyzed [3+2] cycloaddition of azomethine imines with N-allenyl amides was developed to provide two types of pyrazolyl based bicyclic heterocycles. Both pyrazolidin-3-one derived and dihydroisoquinoline derived azomethine imines reacted smoothly with N-allenyl amides to give 6-methylene bipyrazolidin-1-ones and 1-methylene hexahydropyrazolo[5,1-a] isoquinolines in moderate to good yields.