Intramolecular C-C coupling of 2,6-disubstituted-1-bromoaryls for dihydrophenanthridines

The reaction of 2,6-disubstituted-1-bromoaryl imines with sodium borohydride under reflux condition leads to an intramolecular cyclization through C-Br and C-H coupling without any transition-metal catalyst, furnishing 5,6-dihydrophenanthridine and phenanthridine derivatives.