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.