Gold-Catalyzed Formal [3 + 2] Cycloaddition of Ynamides with 4,5-Dihydro-1,2,4-oxadiazoles: Synthesis of Functionalized 4-Aminoimidazoles
作者:Wei Xu、Gaonan Wang、Ning Sun、Yuanhong Liu
DOI:10.1021/acs.orglett.7b01469
日期:2017.6.16
A gold-catalyzed formal [3 + 2] cycloaddition of ynamides with 4,5-dihydro-1,2,4-oxadiazoles has been developed. The reaction provides a concise and regioselective access to highly functionalized 4-aminoimidazoles likely via the formation of an α-imino gold carbene intermediate followed by cyclization. 4,5-Dihydro-1,2,4-oxadiazole was found to act as an efficient N-iminonitrene equivalent in these
Δ2-1,2,4-Oxadiazoline durch Kondensation von Amidoximen mit Ketonen und Aldehyden
作者:Jürgen Lessel
DOI:10.1002/ardp.19933260703
日期:——
Ketone und aromatische Aldehyde cyclisieren in Eisessig mit aromatischen Amidoximen des Typs 1 zu Δ2‐1,2,4‐Oxadiazolinen 3, in neutralen Solventien hingegen bleibt die Reaktion aus. Dieses unterschiedliche Verhalten wird durch MNDO‐Berechnungen erklärt; als reaktive Spezies sind die protonierten Carbonylverbindungen anzunehmen.
Tf<sub>2</sub>NH-catalyzed formal [3 + 2] cycloaddition of oxadiazolones with ynamides: a simple access to aminoimidazoles
作者:Yingying Zhao、Yancheng Hu、Xincheng Li、Boshun Wan
DOI:10.1039/c7ob00701a
日期:——
Oxadiazolones are first employed as the three-atom coupling partners in the Tf2NH-catalyzed cycloaddition with ynamides. This formal [3 + 2] cycloaddition allows a rapid synthesis of aminoimidazoles with a broad substrate scope. The approach also features a metal-free catalytic cycloaddition process, which may find applications in the synthesis of bioactive molecules. Besides, the resulting N-methyl