Carbocations as Lewis Acid Catalysts in Diels-Alder and Michael Addition Reactions
2014 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 20, no 4, 1066-1072 p.Article in journal (Refereed) Published
In general, Lewis acid catalysts are metal-based compounds that owe their reactivity to a low-lying empty orbital. However, one potential Lewis acid that has received negligible attention as a catalyst is the carbocation. We have demonstrated the potential of the carbocation as a highly powerful Lewis acid catalyst for organic reactions. The stable and easily available triphenylmethyl (trityl) cation was found to be a highly efficient catalyst for the Diels-Alder reaction for a range of substrates. Catalyst loadings as low as 500ppm, excellent yields, and good endo/exo selectivities were achieved. Furthermore, by changing the electronic properties of the substituents on the tritylium ion, the Lewis acidity of the catalyst could be tuned to control the outcome of the reaction. The ability of this carbocation as a Lewis acid catalyst was also further extended to the Michael reaction.
Place, publisher, year, edition, pages
2014. Vol. 20, no 4, 1066-1072 p.
carbocations, catalysis, Diels-Alder reactions, Michael addition, organocatalysis, tritylium ions
IdentifiersURN: urn:nbn:se:kth:diva-141061DOI: 10.1002/chem.201304160ISI: 000329548000022ScopusID: 2-s2.0-84892615130OAI: oai:DiVA.org:kth-141061DiVA: diva2:695578
FunderSwedish Research Council
QC 201402112014-02-112014-02-072014-04-25Bibliographically approved