Geometry-dependent divergence in the gold-catalyzed redox cascade cyclization of o-alkynylaryl ketoximes and nitrones leading to isoindoles.
We report geometry-dependent cyclizations of o-alkynylaryl ketoximes and nitrones catalyzed by gold complexes. (E)-Ketoximes undergo N-attack to give isoquinoline-N-oxides. In sharp contrast, (Z)-ketoximes undergo unprecedented O-nucleophilic attack, followed by a redox cascade leading to a novel catalytic entry to isoindoles of diverse scope. The structure of an isoindole was unambiguously supported by X-ray crystallography. We demonstrated the generality of the isoindole synthesis from either (Z)-oximes or nitrones, and presented a mechanistic model of this redox cascade based on the reaction profiles of various substrates.
Department of Chemistry, Hanyang University, 133-791, Seoul, Korea.
Hyun-Suk
HS
Yeom
Youngun
Y
Lee
Ji-Eun
JE
Lee
Seunghoon
S
Shin