Urea activation by an external brønsted acid: Breaking self-association and tuning catalytic performance
In this work, we hypothesize that Brønsted acids can activate urea-based catalysts by diminishing its self-assembly tendency. As a proof of concept, we used the asymmetric Friedel–Crafts alkylation of indoles with nitroalkenes as a benchmark reaction. The resulting 3-substituted indole derivatives w...
| Authors: | ; ; ; ; |
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| Format: | Article |
| Status: | Published version |
| Publication date: | 2018 |
| Country: | España |
| Institution: | Universidad de Zaragoza |
| Repository: | Zaguán. Repositorio Digital de la Universidad de Zaragoza |
| OAI Identifier: | oai:zaguan.unizar.es:74967 |
| Online Access: | http://zaguan.unizar.es/record/74967 |
| Access Level: | Open access |
| Summary: | In this work, we hypothesize that Brønsted acids can activate urea-based catalysts by diminishing its self-assembly tendency. As a proof of concept, we used the asymmetric Friedel–Crafts alkylation of indoles with nitroalkenes as a benchmark reaction. The resulting 3-substituted indole derivatives were obtained with better results due to cooperative effects of the chiral urea and a Brønsted acid additive. Such synergy has been rationalized in terms of disassembly of the supramolecular catalyst aggregates, affording a more acidic and rigid catalytic complex. |
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