Waste-free synthesis of condensed heterocyclic compounds by rhodium-catalyzed oxidative coupling of substituted arene or heteroarene carboxylic acids with alkynes.
The direct oxidative coupling of 2-amino- and 2-hydroxybenzoic acids with internal alkynes proceeds efficiently in the presence of a rhodium/copper catalyst system under air to afford the corresponding 8-substituted isocoumarin derivatives, some of which exhibit solid-state fluorescence. Depending on conditions, 4-ethenylcarbazoles can be synthesized selectively from 2-(arylamino)benzoic acids. The oxidative coupling reactions of heteroarene carboxylic acids as well as aromatic diacids with an alkyne are also described.
Shimizu
Masaki
M
Department of Applied Chemistry, Faculty of Engineering, Osaka University, Suita, Osaka 565-0871, Japan.
Hirano
Koji
K
Satoh
Tetsuya
T
Miura
Masahiro
M