Synthesis of Diamido N‑Heterocyclic Imines (DAC = NH) Via Staudinger or Reductive N–N Bond Cleavage Approach

This report communicates the first examples of N-heterocyclic imines based on electrophilic diamido carbenes (DACs). While 2 is prepared by classical Staudinger synthesis, 4 is obtained via an unusual reductive N–N bond cleavage of an azine by HCl. The exocyclic CN bond lengths in 2 and 4 are substantially shorter than those based on N-heterocyclic carbenes and cyclic (alkyl)(amino)carbene reflecting the electrophilic character of DACs.