Abstract
Several metallocenium derivatives were prepared including N-ferrocenium-N′-phenylthiourea tetrakis-[3,5-bis(trifluoromethyl)phenyl]borate (BArF4, 4a), N-methylferrocenium-N′-phenylthiourea BArF4 (4b) and N-cobaltocenium-N′-phenylthiourea BArF4 (5). These compounds are competent catalysts for the Friedel-Crafts alkylation of indoles with trans-β-nitrostyrenes, and are much more active than their reduced non-charged forms. The iron derivatives are less stable than the cobalt analog and were generated and used in situ whereas the cobalt-containing thiourea was isolated and characterized by X-ray crystallography. All three of these metallocenium salts have Lewis and Brønsted acidic sites which were exploited in tandem to afford charge-activated catalysts.
Original language | English (US) |
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Pages (from-to) | 1788-1793 |
Number of pages | 6 |
Journal | Organic and Biomolecular Chemistry |
Volume | 22 |
Issue number | 9 |
DOIs | |
State | Published - Feb 5 2024 |
Bibliographical note
Publisher Copyright:© 2024 The Royal Society of Chemistry.
PubMed: MeSH publication types
- Journal Article