Organocatalytic Hat Trick: 1,5,7-Triazabicyclo[4.4.0]dec-5-ene (TBD)-Catalyzed Synthesis of Cyclic Imides via an Amidation–Cyclization–Elimination Cascade

1,5,7-Triazabicyclo[4.4.0]dec-5-ene (TBD) was used for the synthesis of cyclic imides via an amidation–cyclization–elimination cascade. This organocatalytic transformation features both the traditional reactivity of TBD and its unprecedented C–C bond cleavage capability, allowing rapid and efficient access to cyclic imides. This method is compatible with the late-stage functionalization of complex molecules and the synthesis of bioactive molecules. Both experimental and computational approaches were employed to gain a better understanding of the reaction mechanism.