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Chiral Lewis base catalyzed enantioselective acetylcyanation of α-oxo esters
KTH, Skolan för kemivetenskap (CHE), Kemi.
KTH, Skolan för kemivetenskap (CHE), Kemi.
KTH, Skolan för kemivetenskap (CHE), Kemi.
KTH, Skolan för kemivetenskap (CHE), Kemi.ORCID-id: 0000-0002-1743-7650
2009 (engelsk)Inngår i: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, Vol. 23, s. 3917-3922Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Acetyl cyanide adds to alkyl benzoylformates and to 2-oxoalkanoates to yield enantioenriched acylated cyanohydrins in one step in the presence of a catalytic amount of a chiral base. The reaction is accelerated by Lewis acids and by the addition of a catalytic amount of methanol. Under optimized conditions, 94% of a 94:6 mixture of the O-acetylated and non-protected cyanohydrins was formed from, methyl benzoylformate in the presence of cinchonidine; from, this mixture the acylated compound with 66% ee was isolated in 77% yield. Ethyl pyruvate and ierf-butyl 2-oxobutanoate were more reactive, and essentially full conversion to the products with 69 and 82% ee, respectively, was achieved. The reaction proceeds by a non-selective addition of cyanide ion to give the non-protected cyanohydrin followed by a dynamic kinetic resolution to provide the enantioenriched acetylated product.

sted, utgiver, år, opplag, sider
2009. Vol. 23, s. 3917-3922
Emneord [en]
Acylation; Addition reactions; Asymmetric catalysis; Cyanides; Kinetic resolution; Lewis bases
HSV kategori
Identifikatorer
URN: urn:nbn:se:kth:diva-10366DOI: 10.1002/ejoc.200900055ISI: 000269103600014Scopus ID: 2-s2.0-68049139704OAI: oai:DiVA.org:kth-10366DiVA, id: diva2:216256
Merknad

Tidigare titel: Chiral Lewis Base-Catalyzed Enantioselective Acetylcyanation of α-Ketoesters QC 20100818

Tilgjengelig fra: 2009-05-07 Laget: 2009-05-07 Sist oppdatert: 2017-12-13bibliografisk kontrollert
Inngår i avhandling
1. New Methods for Chiral Cyanohydrin Synthesis
Åpne denne publikasjonen i ny fane eller vindu >>New Methods for Chiral Cyanohydrin Synthesis
2009 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

This thesis deals with method development in asymmetric catalysis and specifically syntheses of enantioenriched O-functionalized cyanohydrins.

The first part describes the development of a method for the synthesis of O‑alkoxycarbonylated and O-acylated cyanohydrins. Ethyl cyanoformate and acyl cyanides were added to aldehydes in a reaction catalyzed by a chiral dimeric Ti-salen complex together with a tertiary amine. High yields and enantioselectivities were in most cases obtained. Mechanistic studies were performed and a reaction mechanism was proposed. ­

The second part describes a method in which the undesired minor enantiomer in a Lewis acid–Lewis base-catalyzed acylcyanation is continuously recycled into prochiral starting material. Close to enantiopure O‑acylated cyanohydrins were obtained in high yields.

The third part deals with asymmetric acylcyanations of ketones. Acetyl cyanide was found to add to α‑ketoesters in a reaction catalyzed by a chiral Lewis base. Yields up to 77% and 82% ee were obtained.

The final part describes an enzymatic method for high-throughput analysis of O‑acylated cyanohydrins. The enantiomeric excess and conversion were determined for products obtained from a number of aromatic and aliphatic aldehydes.

sted, utgiver, år, opplag, sider
Stockholm: KTH, 2009. s. 54
Serie
Trita-CHE-Report, ISSN 1654-1081 ; 2009:12
Emneord
acyl cyanides, asymmetric synthesis, biocatalysis, cyanide, cyanohydrins, dual activation, enzymes, high-throughput screening, Lewis acid, Lewis base, metal catalysis, minor enantiomer recycling, salen, titanium
HSV kategori
Identifikatorer
urn:nbn:se:kth:diva-10205 (URN)978-91-7415-263-0 (ISBN)
Disputas
2009-05-08, F3, Lindstedtsvägen 26, Stockholm, 10:00 (engelsk)
Opponent
Veileder
Merknad
QC 20100818Tilgjengelig fra: 2009-05-07 Laget: 2009-04-06 Sist oppdatert: 2010-09-22bibliografisk kontrollert

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