Studies on organocatalytic asymmetric Michael addition reactions

Pandya, Keyur M. (2006) Studies on organocatalytic asymmetric Michael addition reactions. Masters thesis, Memorial University of Newfoundland.

[img] [English] PDF - Accepted Version
Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission.

Download (3MB)

Abstract

The development of organocatalysts for asymmetric synthesis continues to be actively investigated in recent years due to the advantages over conventional metal-based catalysts. Research in our laboratory has focused on the development of organocatalysts for fundamental carbon-carbon bond forming reactions, such as the Michael addition reaction. -- The organocatalytic Michael addition of ketones to nitroalkenes is of special interest since the reaction generates two contiguous stereocenters and the products (γ-nitro ketones) are useful synthetic intermediates. We have observed that this reaction is efficiently catalyzed by pyrrolidine-based chiral, secondary diamines as well as triamines. The use of a protic acid in conjunction with the amine catalyst is beneficial and the Michael addition products (syn diastereomers) are obtained with excellent enantioselectivities (up to 99% ee) and diastereoselectivity (up to 50:1 dr) for cyclic ketones and nitroalkenes derived from aromatic aldehydes. Details regarding the effect of changes in the catalyst and protic acid structure, variation of catalyst/protic acid combinations and the scope of the reaction with respect to structural changes in the ketone and nitroalkenes will be discussed. -- In addition, the application of the chiral triamines in Michael reactions involving iminium ion intermediates has been examined. Preliminary results from these studies will be presented. The attempted synthesis of pyrrolidine-based organocatalysts with guanidine-containing side chains as well as catalysts based on the camphor scaffold will also be presented.

Item Type: Thesis (Masters)
URI: http://research.library.mun.ca/id/eprint/11194
Item ID: 11194
Additional Information: Includes bibliographical references.
Department(s): Science, Faculty of > Chemistry
Date: 2006
Date Type: Submission
Library of Congress Subject Heading: Addition reactions; Asymmetric synthesis.

Actions (login required)

View Item View Item

Downloads

Downloads per month over the past year

View more statistics