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Carbocation Catalysis: Oxa-Diels-Alder Reactions of Unactivated Aldehydes and Simple Dienes
KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi. Sohag University, Egypt.
KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.ORCID-id: 0000-0003-1933-4193
2015 (engelsk)Inngår i: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, nr 30, s. 6610-6614Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The versatility of the trityl cation (TrBF<inf>4</inf>) as a highly efficient Lewis acid organocatalyst is demonstrated in the oxa-Diels-Alder reaction of various unactivated aromatic and aliphatic aldehydes and simple unactivated dienes, such as isoprene and 2,3-dimethylbutadiene. The transformation proceeds smoothly to give 3,6-dihydropyrane adducts in high to moderate yields with catalyst loadings down to 1.0 mol-% under mild reaction conditions. In contrast to most previously reported strategies, this protocol does not require substrate functional group activation, neither by electron-deficient aldehydes (2-oxo aldehydes) or electron-rich dienes (methoxy or amino-butadiene).

sted, utgiver, år, opplag, sider
Wiley-VCH Verlagsgesellschaft, 2015. nr 30, s. 6610-6614
Emneord [en]
Carbocations, Cycloaddition, Organocatalysis, Trityl ion
HSV kategori
Identifikatorer
URN: urn:nbn:se:kth:diva-175061DOI: 10.1002/ejoc.201501112ISI: 000363339600005Scopus ID: 2-s2.0-84945478847OAI: oai:DiVA.org:kth-175061DiVA, id: diva2:881626
Merknad

QC 20151211

Tilgjengelig fra: 2015-12-11 Laget: 2015-10-09 Sist oppdatert: 2018-09-26bibliografisk kontrollert
Inngår i avhandling
1. Carbocation Catalysis for Organic Synthesis
Åpne denne publikasjonen i ny fane eller vindu >>Carbocation Catalysis for Organic Synthesis
2018 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

The most common view of carbocations in organic chemistry is that they are short-lived intermediates in several fundamental reactions, e.g. the classic SN1-reaction. However, carbocations that can delocalize their positive charge can be stable enough to be isolated and used as Lewis acid catalysts, phase transfer catalysts or oxidants in various reactions. The theme of this thesis concerns applying trityl cations as Lewis acid catalysts in different organic reactions. The first chapter presents a general introduction of the field of Lewis acids, the characteristics and applications of carbocations in different organic reactions, and the aims of this thesis. The second chapter describes the carbocation-catalyzed asymmetric Diels–Alder reactions assisted by chiral counteranions. The third chapter shows that carbocations can be utilized as catalysts in oxa-Diels–Alder reactions with unactivated aldehydes and dienes as substrates. The fourth chapter investigates the application of carbocation catalysis in bromination reactions for selective functionalization at the benzylic position and on the aromatic ring, respectively. The fifth chapter highlights that carbocation-catalyzed aldehyde–olefin metathesis reactions can be achieved in high yields by suppressing the decomposition of both starting materials and products.

sted, utgiver, år, opplag, sider
Stockholm: KTH Royal Institute of Technology, 2018. s. 54
Serie
TRITA-CBH-FOU ; 2018:44
Emneord
carbocation, trityl cation, Lewis acid catalyst, enantioselective, chiral counteranion, oxa-Diels–Alder, bromination, aldehyde–olefin metathesis
HSV kategori
Forskningsprogram
Kemi
Identifikatorer
urn:nbn:se:kth:diva-235422 (URN)978-91-7729-966-0 (ISBN)
Disputas
2018-10-26, F3, Lindstedtsvägen 26, Stockholm, 14:00 (engelsk)
Opponent
Veileder
Merknad

QC 20180926

Tilgjengelig fra: 2018-09-26 Laget: 2018-09-26 Sist oppdatert: 2018-09-26bibliografisk kontrollert

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