An HFIP-assisted, cobalt-catalyzed three-component electrophilic C-H amination/cyclization/directing group removal cascade to naphtho[1,2-d]imidazoles.

A concise and efficient method has been developed herein for the synthesis of valuable naphtho[1,2-d]imidazole derivatives. It involves an earth-abundant cobalt-catalyzed electrophilic ortho C-H amination/cyclization/directing group removal cascade with O -benzoloxyamines using paraformaldehyde as a one carbon synthon. Picolinamide has been utilized as a traceless directing group. A boosting effect of HFIP is found in the whole process. The reaction conditions are very simple and allow easy handling, making this methodology valuable and appealing.