Elevated by the support: 2‐Alkynyl aniline cycloisomerization to indole is catalyzed by cationic Au NPs on a carbon support. Electroneutral and rich 2‐aryl indoles are further converted into 3,3′‐biindoles by oxidative homocoupling that is readily catalyzed by the Au NPs on carbon, and exclusively but also somewhat sluggishly by the carbon support.

No abstract

Cycloisomerization of 2-Alkynylanilines to Indoles Catalyzed by Carbon-Supported Gold Nanoparticles and Subsequent Homocoupling to 3,3'-Biindoles. -The cycloisomerization of 2-alkynyl substituted anilines (I) is studied using a heterogeneous gold on carbon catalysts. Slightly modified conditions with higher Au loadings and pretreatment with HNO3/HCl allows direct synthesis of 3,3'-biindoles as well as the cyclooctatetraene. -(PEREA-BUCETA, J. E.; WIRTANEN, T.; LAUKKANEN, O.-V.; MAEKELAE, M. K.; NIEGER, M.; MELCHIONNA, M.; HUITTINEN, N.; LOPEZ-SANCHEZ*, J. A.; HELAJA, J.; Angew. Chem., Int. Ed. 52 (2013) 45, 11835-11839, http://dx.doi.org/10.1002/anie.201305579 ; Dep. Chem., Univ. Liverpool, Liverpool L69 7ZD, UK; Eng.) -Mais 14-128