ChemInform Abstract: Synthesis of 2,3-Disubstituted Indoles via Palladium-Catalyzed Annulation of Internal Alkynes.

✍ Scribed by R. C. Larock; E. K. Yum; M. D. Refvik

• Publisher: John Wiley and Sons
• Year: 2010
• Weight: 40 KB
• Volume: 30
• Category: Article
• ISSN: 0931-7597
• DOI: 10.1002/chin.199912133

✦ Synopsis

1999

indole derivatives, isoindole derivatives indole derivatives, isoindole derivatives R 0140

12 -133

Synthesis of 2,3-Disubstituted Indoles via Palladium-Catalyzed Annulation of Internal Alkynes.

-Iodoaniline (I) and the corresponding N-acetyl, -methyl, and -tosyl derivatives are coupled with a wide variety of alkynes (30 examples) to provide indoles in good to excellent yields. The best results are obtained by employing an excess of the alkyne and a base and additionally one equivalent of either LiCl or Bu 4 NCl. The reaction is quite regioselective, placing the aryl group of the aniline on the less sterically hindered end of the triple bond and the nitrogen moiety on the more sterically hindered end. The presence of alcohol groups in the alkyne seems to have a particularly strong directing effect. The chemoselectivity of the annulation process is apparently very high, because no products of alkene substitution are formed from the reaction with alkenynol (IVc). -(LAROCK, R. C.; YUM,