TY - JOUR AU - Sonsona, I.G. AU - Marqués-López, E. AU - Häring, M. AU - Díaz, D.D. AU - Herrera, R.P. T1 - Urea activation by an external brønsted acid: Breaking self-association and tuning catalytic performance LA - eng PY - 2018 T2 - Catalysts SN - 2073-4344 VL - 8 IS - 8 PB - MDPI AG PP - Basel AB - 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. DO - 10.3390/CATAL8080305 UR - https://portalciencia.ull.es/documentos/5fa08028299952440aae78cf DP - Dialnet - Portal de la Investigación ER -