Copper, Silver and Sodium Salt‐Mediated Quaternization by Arylation: Syntheses of N‐Heterocyclic Carbene Precursors and 6‐ H ‐Phenanthridine Derivatives

We have developed a Cu II ‐, Ag I ‐, and NaOTf‐mediated intramolecular quaternization by arylation reactions to synthesize a variety of N‐heterocyclic carbene (NHC) precursors with a benzene‐fused backbone. The methodology also provides a convenient alternative route for the synthesis of 6‐ H ‐phenanthridine derivatives. A novel silver–NHC complex was prepared by treatment of Ag 2 O with the free carbene, which was in situ prepared from the deprotonation of a representative quinazolinonium salt.