Part 1: development of a base-free methodology for the NHC-catalyzed intermolecular stetter reaction. Part 2: Chiral anion mediated asymmetric stetter reaction

Part I: Development of a base-free methodology for the NHC- catalyzed Intermolecular Stetter Reaction. We succeeded in developing a base-free methodology for the NHC-catalyzed intermolecular Stetter reaction by employing CsF as a dual Lewis acid/base activating reagent, achieving the desired 1,4...

Full description

Saved in:
Bibliographic Details
Main Author: Choo, Joy En
Other Authors: Loh Teck Peng
Format: Theses and Dissertations
Language:English
Published: 2010
Subjects:
Online Access:http://hdl.handle.net/10356/42099
Tags: Add Tag
No Tags, Be the first to tag this record!
Institution: Nanyang Technological University
Language: English
id sg-ntu-dr.10356-42099
record_format dspace
spelling sg-ntu-dr.10356-420992023-02-28T23:35:42Z Part 1: development of a base-free methodology for the NHC-catalyzed intermolecular stetter reaction. Part 2: Chiral anion mediated asymmetric stetter reaction Choo, Joy En Loh Teck Peng School of Physical and Mathematical Sciences DRNTU::Science::Chemistry::Organic chemistry::Organic synthesis Part I: Development of a base-free methodology for the NHC- catalyzed Intermolecular Stetter Reaction. We succeeded in developing a base-free methodology for the NHC-catalyzed intermolecular Stetter reaction by employing CsF as a dual Lewis acid/base activating reagent, achieving the desired 1,4-dicarbonyl structural scaffold under ultrasonication reaction condition. Generally, moderate to excellent yields were obtained. Yields were especially good when highly reactive Michael acceptors were employed in conjuction with an aromatic carbinol carrying electron withrdrawing subtituents. In all cases, this transformation only generated the desired 1,4-dicarbonyl product with no observation of benzoin products as commonly observed with other reaction routes. Unfortunately, sterically hindered carbinols and α-substituted Michael acceptors are not well tolerated in this reaction. Part II: Chiral anion mediated Stetter Reaction. A preliminary study was carried out on the feasibility of inducing an enantioselective Stetter reaction by chiral anions. Several reports show that highly efficient enantioselective induction could be obtained with chiral cations and anions when there exists a tight ion contact pair in the chemical transformation. We propose that such intimate ion pairing might be possible in the key breslow intermediate for chiral anion mediated enantioselectivity in the Stetter reaction. ​Master of Science 2010-09-16T08:20:23Z 2010-09-16T08:20:23Z 2009 2009 Thesis http://hdl.handle.net/10356/42099 en 119 p. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic DRNTU::Science::Chemistry::Organic chemistry::Organic synthesis
spellingShingle DRNTU::Science::Chemistry::Organic chemistry::Organic synthesis
Choo, Joy En
Part 1: development of a base-free methodology for the NHC-catalyzed intermolecular stetter reaction. Part 2: Chiral anion mediated asymmetric stetter reaction
description Part I: Development of a base-free methodology for the NHC- catalyzed Intermolecular Stetter Reaction. We succeeded in developing a base-free methodology for the NHC-catalyzed intermolecular Stetter reaction by employing CsF as a dual Lewis acid/base activating reagent, achieving the desired 1,4-dicarbonyl structural scaffold under ultrasonication reaction condition. Generally, moderate to excellent yields were obtained. Yields were especially good when highly reactive Michael acceptors were employed in conjuction with an aromatic carbinol carrying electron withrdrawing subtituents. In all cases, this transformation only generated the desired 1,4-dicarbonyl product with no observation of benzoin products as commonly observed with other reaction routes. Unfortunately, sterically hindered carbinols and α-substituted Michael acceptors are not well tolerated in this reaction. Part II: Chiral anion mediated Stetter Reaction. A preliminary study was carried out on the feasibility of inducing an enantioselective Stetter reaction by chiral anions. Several reports show that highly efficient enantioselective induction could be obtained with chiral cations and anions when there exists a tight ion contact pair in the chemical transformation. We propose that such intimate ion pairing might be possible in the key breslow intermediate for chiral anion mediated enantioselectivity in the Stetter reaction.
author2 Loh Teck Peng
author_facet Loh Teck Peng
Choo, Joy En
format Theses and Dissertations
author Choo, Joy En
author_sort Choo, Joy En
title Part 1: development of a base-free methodology for the NHC-catalyzed intermolecular stetter reaction. Part 2: Chiral anion mediated asymmetric stetter reaction
title_short Part 1: development of a base-free methodology for the NHC-catalyzed intermolecular stetter reaction. Part 2: Chiral anion mediated asymmetric stetter reaction
title_full Part 1: development of a base-free methodology for the NHC-catalyzed intermolecular stetter reaction. Part 2: Chiral anion mediated asymmetric stetter reaction
title_fullStr Part 1: development of a base-free methodology for the NHC-catalyzed intermolecular stetter reaction. Part 2: Chiral anion mediated asymmetric stetter reaction
title_full_unstemmed Part 1: development of a base-free methodology for the NHC-catalyzed intermolecular stetter reaction. Part 2: Chiral anion mediated asymmetric stetter reaction
title_sort part 1: development of a base-free methodology for the nhc-catalyzed intermolecular stetter reaction. part 2: chiral anion mediated asymmetric stetter reaction
publishDate 2010
url http://hdl.handle.net/10356/42099
_version_ 1759853773034881024