Cu(OTf) 2 Enhanced Intramolecular Nucleophilic N -Arylation of 2-Amino-3-arylquinolines.

In the presence of Cu(OTf) 2 (5 mol %) and KO t Bu, a synergistic effect of the N -arylation process on 2-amino-3-arylquinolines is observed. Within 4 h, this method provides a wide variety of norneocryptolepine analogues with good to excellent yields. Overall, a double heteroannulation strategy for the synthesis of indoloquinoline alkaloids from nonheterocyclic precursors is demonstrated. Mechanistic investigations establish that the reaction proceeds via the S N Ar pathway. Despite moderate yields, the one-pot, two-step double heteroannulation illustrates that this procedure is highly atom-efficient. Neocryptolepine, a natural product, is also synthesized from indoloquinoline. A brief study of the photophysical properties of selected norneocryptolepine analogues is also discussed.