Synthesis of Acridines and Phenazines

Ellman and coworkers reported a new [3+3] annulation reaction for the preparation of acridines and phenazines by Rh(III)-catalyzed C-H amination of aromatic imines and azobenzenes with aromatic azides. The reaction mechanism proceeds by C-H activation followed by intramolecular electrophilic aromatic substitution and aromatization to offer the respective products. Equations (5.81)-(5.83) illustrate that a broad range of acridines and phenazines can be generated with diverse functionality [44]. 

You et al. developed a simple and convenient method for the synthesis of cinno-lines 87 by Rh-catalyzed oxidative C-H activation/cyclization of azo compounds with alkynes [45]. In this reaction, -Bu acts as a leaving group and also promotes the C-N reductive elimination however, the reaction works only for aliphatic internal alkynes with moderate yield (Eq. (5.84)). 

---