Efficient Methods for the Synthesis of Benzopyrano[3,4-<i>c</i>]pyrrolidines by Catalyzed 1,3-Dipolar Cycloaddition of Azomethine Ylides with 3-Substituted Coumarins
Abstract With triethylamine as a catalyst, the 1,3-dipolarcycloaddition of azomethine ylides with 3-substituted coumarins proceeded smoothly under mild conditions to afford the desired products benzopyrano[3,4-c]pyrrolidines in good to excellent yields.