Next Article in Journal
Promotional Effect of Cerium and/or Zirconium Doping on Cu/ZSM-5 Catalysts for Selective Catalytic Reduction of NO by NH3
Previous Article in Journal
Ionic Liquids as Bifunctional Cosolvents Enhanced CO2 Conversion Catalysed by NADH-Dependent Formate Dehydrogenase
Open AccessArticle

Urea Activation by an External Brønsted Acid: Breaking Self-Association and Tuning Catalytic Performance

1
Laboratorio de Organocatálisis Asimétrica, Departamento de Química Orgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH) CSIC-Universidad de Zaragoza, C/ Pedro Cerbuna 12, 50009 Zaragoza, Spain
2
Institut für Organische Chemie, Universität Regensburg Universitätsstr. 31, 93053 Regensburg, Germany
3
Institute of Advanced Chemistry of Catalonia-Spanish National Research Council (IQAC-CSIC), Jordi Girona 18-26, 08034 Barcelona, Spain
*
Authors to whom correspondence should be addressed.
Catalysts 2018, 8(8), 305; https://doi.org/10.3390/catal8080305
Received: 8 July 2018 / Revised: 24 July 2018 / Accepted: 25 July 2018 / Published: 28 July 2018
(This article belongs to the Special Issue Hydrogen Bonding Activation)
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. View Full-Text
Keywords: Brønsted acids; Friedel-Crafts; organocatalysis; self-association; synergy; urea Brønsted acids; Friedel-Crafts; organocatalysis; self-association; synergy; urea
Show Figures

Graphical abstract

MDPI and ACS Style

Sonsona, I.G.; Marqués-López, E.; Häring, M.; Díaz, D.D.; Herrera, R.P. Urea Activation by an External Brønsted Acid: Breaking Self-Association and Tuning Catalytic Performance. Catalysts 2018, 8, 305.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop