1539093-70-3Relevant academic research and scientific papers
Cobalt-catalysed reductive C-H alkylation of indoles using carboxylic acids and molecular hydrogen
Cabrero-Antonino, Jose R.,Adam, Rosa,Junge, Kathrin,Beller, Matthias
, p. 6439 - 6450 (2017/08/29)
The direct CH-alkylation of indoles using carboxylic acids is presented for the first time. The catalytic system based on the combination of Co(acac)3 and 1,1,1-tris(diphenylphosphinomethyl)-ethane (Triphos, L1), in the presence of Al(OTf)3 as co-catalyst, is able to perform the reductive alkylation of 2-methyl-1H-indole with a wide range of carboxylic acids. The utility of the protocol was further demonstrated through the C3 alkylation of several substituted indole derivatives using acetic, phenylacetic or diphenylacetic acids. In addition, a careful selection of the reaction conditions allowed to perform the selective C3 alkenylation of some indole derivatives. Moreover, the alkenylation of C2 position of 3-methyl-1H-indole was also possible. Control experiments indicate that the aldehyde, in situ formed from the carboxylic acid hydrogenation, plays a central role in the overall process. This new protocol enables the direct functionalization of indoles with readily available and stable carboxylic acids using a non-precious metal based catalyst and hydrogen as reductant.
Gold-catalyzed annulations of allenes with N-hydroxyanilines to form indole derivatives with benzaldehyde as a promoter
Kawade, Rahul Kisan,Huang, Po-Han,Karad, Somnath Narayan,Liu, Rai-Shung
supporting information, p. 737 - 740 (2014/01/23)
Gold-catalyzed syntheses of 2,3-disubstituted indole derivatives from N-hydroxyanilines and allenes are described; these reactions require benzaldehyde as an additive to generate nitrones in situ. Our control experiments indicate that nitrones and water were indispensable in the reactions whereas N-hydroxyanilines alone were inactive nucleophiles. This synthetic method is compatible with allenes and N-hydroxyanilines with a reasonable range, further highlighting its synthetic utility.
