Regioselective Synthesis of 3-Bromoquinoline Derivatives and Diastereoselective Synthesis of Tetrahydroquinolines via Acid-Promoted Rearrangement of Arylmethyl Azides.

Regioselective synthesis of 3-bromoquinoline derivatives was achieved via a formal [4 + 2]-cycloaddition between N-aryliminium ion, generated from arylmethyl azides, and 1-bromoalkynes. This method could also be applied to other quinoline derivatives using appropriate alkynes. Moreover, the current strategy could be utilized for the diastereoselective synthesis of tetrahydroquinoline derivatives employing alkenyl substrates in good to excellent yields.