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Quantum Chemical Studies of Enantioselective Organocatalytic Reactions
KTH, School of Biotechnology (BIO), Theoretical Chemistry.
2008 (English)Licentiate thesis, comprehensive summary (Other scientific)
Abstract [en]

Density Functional Theory is used in order to shed light on the reaction mechanisms and the origins of stereoselectivity in enantioselective organocatalytic reactions. The reactions investigated are the dipeptide-catalyzed aldol reaction, the cinchona thiourea-catalyzed nitroaldol reaction and the prolinol derivative-catalyzed hydrophosphination reaction. We can justify the stereoselectivity in the reactions from the energies arising from different interactions in the transition states. The major contributions to the energy differences are found to be hydrogen bond-type attractions and steric repulsions. This knowledge will be useful in the design of improved catalysts as well as general understanding of the basis of selection in other reactions.

Place, publisher, year, edition, pages
Stockholm: KTH , 2008. , vii, 30 p.
Series
Trita-BIO-Report, ISSN 1654-2312 ; 2008:6
Keyword [en]
DFT, enantioselective, asymmetric, organocatalysis
National Category
Theoretical Chemistry
Identifiers
URN: urn:nbn:se:kth:diva-4701ISBN: 978-91-7178-934-1 (print)OAI: oai:DiVA.org:kth-4701DiVA: diva2:13513
Presentation
2008-04-29, FB52, Albanova, Roslagstullsbacken 21, Stockholm, 10:15
Supervisors
Note
QC 20101111Available from: 2008-04-22 Created: 2008-04-22 Last updated: 2010-11-11Bibliographically approved
List of papers
1. Density Functional Theory Study of the Stereoselectivity in Small Peptide-Catalyzed Intermolecular Aldol Reactions
Open this publication in new window or tab >>Density Functional Theory Study of the Stereoselectivity in Small Peptide-Catalyzed Intermolecular Aldol Reactions
2008 (English)In: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 19, 1617-1621 p.Article in journal (Refereed) Published
Abstract [en]

The origins of the stereoselection of the dipeptide-catalyzed intermolecular aldol reaction are explored by means of hybrid density functional theory. Transition states were located for the (S)-ala-(S)-ala-catalyzed aldol reaction with cyclohexanone as the donor and benzaldehyde as the acceptor. The calculations reproduce the experimental trends very satisfactorily. It is demonstrated that the main Source of stereoselectivity is the interaction of the N-terminal amino acid side chain of the dipeptide with the cyclohexene ring.

Keyword
asymmetric-synthesis, enantioselective aldol, versatile catalysts, transition-states, amino-acids, proline, aldehydes, water, organocatalysis, mechanism
National Category
Other Basic Medicine
Identifiers
urn:nbn:se:kth:diva-8240 (URN)10.1016/j.tetasy.2008.06.014 (DOI)000258433400016 ()2-s2.0-48949114919 (Scopus ID)
Note
QC 20100716Available from: 2008-04-22 Created: 2008-04-22 Last updated: 2017-12-14Bibliographically approved
2. Enantioselective Organocatalytic Hydrophosphination of α,β-Unsaturated Aldehydes
Open this publication in new window or tab >>Enantioselective Organocatalytic Hydrophosphination of α,β-Unsaturated Aldehydes
Show others...
2007 (English)In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 46, no 24, 4507-4510 p.Article in journal (Refereed) Published
Abstract [en]

Keeping it simple: Optically active phosphine derivatives can be obtained in high yields and in up to 99% ee by using simple chiral amines to catalyze the hydrophosphination of α,β-unsaturated aldehydes (see scheme, green sphere = chiral group). The synthetic utility of this highly chemo- and enantioselective transformation was exemplified by the one-pot asymmetric synthesis of β-phosphine oxide acids.

Keyword
Aldehydes, Asymmetric synthesis, Conjugate addition, Organocatalysis, Phosphanes
National Category
Other Basic Medicine
Identifiers
urn:nbn:se:kth:diva-8241 (URN)10.1002/anie.200700916 (DOI)000247500600018 ()2-s2.0-34250780536 (Scopus ID)
Note
QC 20100716Available from: 2008-04-22 Created: 2008-04-22 Last updated: 2017-12-14Bibliographically approved
3. Organocatalytic Asymmetric Addition of Phosphorus Nucleophiles to α,β-Unsaturated Aldehydes: Mechanism and Scope
Open this publication in new window or tab >>Organocatalytic Asymmetric Addition of Phosphorus Nucleophiles to α,β-Unsaturated Aldehydes: Mechanism and Scope
Show others...
(English)Article in journal (Other academic) Submitted
National Category
Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-8242 (URN)
Note
QS 20120327Available from: 2008-04-22 Created: 2008-04-22 Last updated: 2012-03-27Bibliographically approved
4. Density Functional Theory Study of the Cinchona Thiourea-Catalyzed Henry reaction: Mechanism and Enantioselectivity
Open this publication in new window or tab >>Density Functional Theory Study of the Cinchona Thiourea-Catalyzed Henry reaction: Mechanism and Enantioselectivity
2007 (English)In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 349, no 17-18, 2537-2548 p.Article in journal (Refereed) Published
Abstract [en]

We report a density functional theory investigation of the enantioselective Cinchona thiourea-catalyzed Henry reaction of aromatic aldehydes with nitromethane. We show that two pathways (differing in the binding modes of the reactants to the catalyst) are possible for the formation of the C-C bond, and that they have comparable reaction barriers. The enantioselectivity is investigated, and our results are in agreement with the experimentally observed solvent dependence of the reaction.

Keyword
cinchona alkaloids, density functional theory, enantioselectivity, nitroaldol reaction, organocatalysis
National Category
Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-8243 (URN)10.1002/adsc.200700367 (DOI)000251737500003 ()2-s2.0-37349098707 (Scopus ID)
Note
QC 20100719Available from: 2008-04-22 Created: 2008-04-22 Last updated: 2017-12-14Bibliographically approved

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