Cobalt-catalysed reductive C-H alkylation of indoles using carboxylic acids and molecular hydrogen
Cabrero-Antonino, JR; Adam, R; Junge, K; Beller, M
| HERO ID | 4641298 |
|---|---|
| In Press | No |
| Year | 2017 |
| Title | Cobalt-catalysed reductive C-H alkylation of indoles using carboxylic acids and molecular hydrogen |
| Authors | Cabrero-Antonino, JR; Adam, R; Junge, K; Beller, M |
| Journal | Chemical Science |
| Volume | 8 |
| Issue | 9 |
| Page Numbers | 6439-6450 |
| Abstract | 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. |
| Doi | 10.1039/c7sc02117h |
| Pmid | 29163930 |
| Wosid | WOS:000408168600067 |
| Is Certified Translation | No |
| Dupe Override | No |
| Is Public | Yes |
| Language Text | English |