An efficient synthesis of indol-3-yl benzonaphthyridines via copper(II) triflate-catalyzed heteroannulation

An efficient and convenient method for the synthesis of indol-3-yl benzo[b][1,6]- and benzo[c][2,7]naphthyridines via copper(II) triflate-catalyzed heteroannulation is reported. This method gives new analogues of indole containing benzonaphthyridines from easily accessible starting materials. This reaction proceeds under mild conditions.