Dearomatization of 3‐Nitroindoles by a Phosphine‐Catalyzed Enantioselective [3+2] Annulation Reaction

• Published in: Angewandte Chemie International Edition Vol. 58; no. 16; pp. 5427 - 5431
• Main Authors: Li, Kaizhi, Gonçalves, Théo P., Huang, Kuo‐Wei, Lu, Yixin
• Format: Journal Article
• Language: English
• Published: WEINHEIM Wiley 08.04.2019; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: [3+2] annulation; Chemical reactions; Chemistry; Chemistry, Multidisciplinary; cyclopentaindolines; dearomatization; Enantiomers; nitroindoles; Organic chemistry; organocatalysis; Phosphine; Physical Sciences; Science & Technology; ASYMMETRIC DEAROMATIZATION; DIELS-ALDER; CRYSTAL-STRUCTURE; dearomatization; 3-ISOTHIOCYANATO OXINDOLES; [3+2] annulation; nitroindoles; INDOLES; CASCADE REACTION; organocatalysis; cyclopentaindolines; CONSTRUCTION; CYCLOADDITION REACTION; DERIVATIVES; ACCESS
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201900248

The dearomatization of 3‐nitroindoles through a chiral‐phosphine‐mediated [3+2] annulation reaction is described. This method makes use of readily available 3‐nitroindoles as an aromatic feedstock and rapidly delivers a wide range of cyclopentaindoline alkaloid scaffolds in a highly enantioselective manner. Notably, phosphine‐triggered cyclization has not been utilized previously in a dearomatization process. A disruptive influence: Variously substituted 3‐nitroindoles underwent dearomatization in a phosphine‐catalyzed asymmetric [3+2] annulation reaction with allenoates (see scheme). This method makes use of 3‐nitroindoles as a readily available aromatic feedstock and provides access to a wide range of cyclopentaindolines in a highly enantioselective manner.