The [3+2] Annulation of CF₃-Ketimines by Re Catalysis: Access to CF₃-Containing Amino Heterocycles and Polyamides

Transition metal catalyzed [3 + 2] annulation of imines with double bonds via directed C-H activation offers a direct access to amino cyclic motifs. However, owing to weak coordination and steric hindrance, trifluoromethylated ketimines have been an unaddressed challenge for TM-catalyzed annulations. Here, a rhenium-catalyzed [3 + 2] annulation of trifluoromethylated ketimines with isocyanates via C(sp²)-H activation has been disclosed. This approach provides an efficient platform for rapid access to a privileged library of CF₃-containing iminoisoindolinones and polyamides by utilizing challenging CF₃-ketimines as the annulation component. The capability of gram scale synthesis, the post-functionalization of the cyclization adduct, the derivation of complex natural molecules and the facile synthesis of polyamides highlight a diversity of synthetic potential of the current methodology.