CuCN-Mediated Cascade Cyclization of 4‑(2-Bromophenyl)-2-butenoates: A High-Yield Synthesis of Substituted Naphthalene Amino Esters

A new method of CuCN-mediated one-pot cyclization of 4-(2-bromophenyl)-2-butenoates leading to efficient synthesis of substituted naphthalene amino esters including phenanthrene aromatic structural units is described. Deuterium labeling studies establish that this one-pot cascade cyclization proceeds through isomerization of olefin, intramolecular C–C bond cyclization, and aromatization as the key intermediates, all occurring in a single step.