Lewis acids have been used as a mediator or a catalyst so far mainly for activation of heteroatom-containing compounds like carbonyl compounds, imines and alkyl halides. In contrast, we have been focusing on developing new carbon-carbon bond forming reactions utilizing activation of hydrocarbons by a metal sulfonate catalyst. In this context, we found that arenes as well as heterocyclic arenes add to alkynes in the presence of indium triflate [In(OTf)3, Tf = SO2CF3] as a catalyst. These findings are followed by development of facile synthesis of aryl- and heteroarylannulated[a]carbazoles by the reaction of propargyl ethers with 2-aryl- and 2-heteroarylindoles. In addition to the above reactions, metal Inflates catalyzed dimerization of vinylarenes with the aid of a palladium catalyst (activation of C = C), nucleophilic substitution using a pyrrolyl group as a carbon leaving group (activation of C-C) and oxidative coupling between lactams and heterocyclic arenes (activation of C-H).
|Number of pages||14|
|Journal||Yuki Gosei Kagaku Kyokaishi/Journal of Synthetic Organic Chemistry|
|Publication status||Published - Jul 2006|
- Heterocyclic arene
- Lewis acid
- Metal triflate