Copper-Catalyzed Selective Benzylic C-O Cyclization of N-o-Tolylbenzamides: Synthesis of 4H-3,1-Benzoxazines

A novel Selectfluor-mediated copper-catalyzed highly selective benzylic C-O cyclization for the synthesis 4H-3,1-benzoxazines is reported. The predominant selectivity for a benzylic C(sp(3))-H over an aromatic C(sp(2))-H bond in N-o-tolylbenzamides is achieved.