Synthesis of Azolo[1,3,5]triazines via Rhodium(III)-Catalyzed Annulation of N-Azolo Imines and Dioxazolones.

A wide range of azolo[1,3,5]triazines were obtained by Rh(III)-catalyzed annulation of N-azolo imines and dioxazolones. The reaction proceeds by the first catalytic C-H amidation of an imidoyl C-H bond followed by cyclodehydration. Good yields were obtained for N-azolo imines derived from aminoazoles and aromatic and heteroaromatic aldehydes. A range of dioxazolone amidating reagents were employed to introduce aryl, heteroaryl, and alkyl substituents. The reaction was also performed with a benchtop setup at 1 mmol scale using microwave heating.