Iodination of remote ortho-C-H bonds of arenes via directed S(E)Ar: a streamlined synthesis of tetrahydroquinolines.

A new strategy for the synthesis of tetrahydroquinolines (THQs) via the sequential functionalizations of remote C-H bonds is reported. This method uses a single picolinamide directing/protecting group to effect Pd-catalyzed γ-C(sp(3))-H arylation, metal-free ε-C(sp(2))-H iodination, and Cu-catalyzed intramolecular C-N cross-coupling. The overall sequence is efficient and versatile, and offers a streamlined synthesis of THQs with complex substitution patterns from readily available aryl iodide and aliphatic amine precursors.