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Rhodium‐Catalyzed CH Annulation of Nitrones with Alkynes: A Regiospecific Route to Unsymmetrical 2,3‐Diaryl‐Substituted Indoles
Author(s) -
Yan Hao,
Wang Haolong,
Li Xincheng,
Xin Xiaoyi,
Wang Chunxiang,
Wan Boshun
Publication year - 2015
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201503997
Subject(s) - annulation , regioselectivity , rhodium , chemistry , indole test , nitrone , aryl , alkyne , stereochemistry , ring (chemistry) , catalysis , medicinal chemistry , combinatorial chemistry , organic chemistry , cycloaddition , alkyl
The direct CH annulation of anilines or related compounds with internal alkynes provides straightforward access to 2,3‐disubstituted indole products. However, this transformation proceeds with poor regioselectivity in the synthesis of unsymmetrically 2,3‐diaryl substituted indoles. Herein, we report the rhodium(III)‐catalyzed CH annulation of nitrones with symmetrical diaryl alkynes as an alternative method to prepare 2,3‐diaryl‐substituted N‐unprotected indoles with two different aryl groups. One of the aryl substituents is derived from NC‐aryl ring of the nitrone and the other from the alkyne substrate, thus providing the indole products with exclusive regioselectivity.