Pd/C-Catalyzed Dehydrogenative [3+2] Cycloaddition for the Synthesis of Functionalized Tropanes

A Pd/C-catalyzed cascade approach for the synthesis of attractive benzo-fused tropanes was developed. The reaction proceeds through a sequential Pd/C-catalyzed dehydrogenative formation of azomethine ylides from amines and 1,3-dipolar cycloaddition. It allows the generation of structurally complex benzo-fused tropanes in good yields with excellent diastereoselectivities under mild reaction conditions. Preliminary results of asymmetric version of the reaction reveal that the copper catalyst and chiral monophosphoramidite ligand can furnish optically active products with moderate ee.