AuCl-catalyzed [4+2] benzannulation between o-alkynyl(oxo)benzene and benzyne.
[Structure: see text] The AuCl-catalyzed benzannulation of o-alkynyl(oxo)benzenes with benzenediazonium 2-carboxylate proceeds under mild conditions and a variety of anthracene derivatives, having a ketone group at the 9-position, are produced in good to high yields. The reaction proceeds most probably through the [4+2] cycloaddition between benzyne and benzopyrylium auric ate complex, which would be generated by the gold-induced electrophilic cyclization of o-alkynyl(oxo)benzenes.
Asao
Naoki
N
Department of Chemistry, and Research and Analytical Center for Giant Molecules, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan. asao@mail.tains.tohoku.ac.jp
Sato
Kenichiro
K