Licentiate Thesis

Quantum Chemical Studies of Enantioselective Organocatalytic Reactions

Defence

Defendant: Peter Hammar

Time: Tuesday 2008-04-29, 10:15

Place: FB51, AlbaNova

Opponents: Dr. Timofei Privalov, Dept. of Organic Chemistry, Stockholm University and Dr. Pekka Mark, Dept of Theoretical Chemistry, Royal Inst. of Technology, Stockholm

Supervisor: Dr. Fahmi Himo

Abstract

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.

2008, ISBN 978-91-7178-934-1

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