Design of novel organocatalysts for asymmetric carbon-carbon bonds formation reactions

In this project, a siloxy serine organocatalyst was developed for the asymmetric aldol reaction and Mannich reactions using either water or ionic liquids as the reaction medium. The synthesis of the organocatalyst using Z-protected serine amino acid was economical and operationally simple. In...

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Main Author: Teo, Yong Chua
Other Authors: National Institute of Education
Format: Research Report
Language:English
Published: 2011
Subjects:
Online Access:http://hdl.handle.net/10356/42739
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author Teo, Yong Chua
author2 National Institute of Education
author_facet National Institute of Education
Teo, Yong Chua
author_sort Teo, Yong Chua
collection NTU
description In this project, a siloxy serine organocatalyst was developed for the asymmetric aldol reaction and Mannich reactions using either water or ionic liquids as the reaction medium. The synthesis of the organocatalyst using Z-protected serine amino acid was economical and operationally simple. In chapter 2, the siloxy serine organocatalyst was shown to function as an efficient organocatalyst for the asymmetric aldol reaction using cyclic ketones as substrates in water. The direct aldol reaction between a selection of aromatic aldehydes and cyclohexanone resulted in good yields and high enantioselectivities (up to 98%) of anti-configured aldol products. In addition, the catalyst was also able to catalyze the preparation of syn-configured aldol products using TBDPSO-protected hydroxy acetone with a variety of aldehydes. The recyclability of this organocatalyst was also demonstrated using similar substrate scopes by extending the direct aldol reaction to the ionic liquid [bmim][BF4]. It is worth to note that the organocatalyst can be reused up to four times with comparable yields and selectivities (up to 92% ee). Comparable results were also obtained in the case TBDPSO-protected hydroxy acetone as the aldol donor.
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spelling ntu-10356/427392020-11-01T06:06:48Z Design of novel organocatalysts for asymmetric carbon-carbon bonds formation reactions Teo, Yong Chua National Institute of Education DRNTU::Science::Chemistry::Organic chemistry::Organic synthesis In this project, a siloxy serine organocatalyst was developed for the asymmetric aldol reaction and Mannich reactions using either water or ionic liquids as the reaction medium. The synthesis of the organocatalyst using Z-protected serine amino acid was economical and operationally simple. In chapter 2, the siloxy serine organocatalyst was shown to function as an efficient organocatalyst for the asymmetric aldol reaction using cyclic ketones as substrates in water. The direct aldol reaction between a selection of aromatic aldehydes and cyclohexanone resulted in good yields and high enantioselectivities (up to 98%) of anti-configured aldol products. In addition, the catalyst was also able to catalyze the preparation of syn-configured aldol products using TBDPSO-protected hydroxy acetone with a variety of aldehydes. The recyclability of this organocatalyst was also demonstrated using similar substrate scopes by extending the direct aldol reaction to the ionic liquid [bmim][BF4]. It is worth to note that the organocatalyst can be reused up to four times with comparable yields and selectivities (up to 92% ee). Comparable results were also obtained in the case TBDPSO-protected hydroxy acetone as the aldol donor. RP5/06 2011-01-10T04:37:47Z 2011-01-10T04:37:47Z 2010 2010 Research Report http://hdl.handle.net/10356/42739 en 33 p. application/pdf
spellingShingle DRNTU::Science::Chemistry::Organic chemistry::Organic synthesis
Teo, Yong Chua
Design of novel organocatalysts for asymmetric carbon-carbon bonds formation reactions
title Design of novel organocatalysts for asymmetric carbon-carbon bonds formation reactions
title_full Design of novel organocatalysts for asymmetric carbon-carbon bonds formation reactions
title_fullStr Design of novel organocatalysts for asymmetric carbon-carbon bonds formation reactions
title_full_unstemmed Design of novel organocatalysts for asymmetric carbon-carbon bonds formation reactions
title_short Design of novel organocatalysts for asymmetric carbon-carbon bonds formation reactions
title_sort design of novel organocatalysts for asymmetric carbon carbon bonds formation reactions
topic DRNTU::Science::Chemistry::Organic chemistry::Organic synthesis
url http://hdl.handle.net/10356/42739
work_keys_str_mv AT teoyongchua designofnovelorganocatalystsforasymmetriccarboncarbonbondsformationreactions