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Title: Application of the stereodivergent oxy-michael cyclisation to the synthesis of natural products and organocatalytic asymmetric aldol reactions in water
Author: Hsiao, Yin-Ting
ISNI:       0000 0004 7227 1168
Awarding Body: University of York
Current Institution: University of York
Date of Award: 2017
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This work outlines two different projects. The first project was the study of a stereodivergent oxy-Michael cyclisation and its application towards the synthesis of natural products, diospongin A, diospongin B and psymberin/ircinistatin A. The α,β-unsaturated thioesters under TBAF-mediated conditions gave the 2,6-trans-tetrahydropyran; under acid-mediated conditions gave the 2,6-cis-tetrahydropyran. The 4-hydroxyl group is crucial for the stereodivergence; when the hydroxyl group was removed or protected the stereodivergence vanished. The second project was the study of (L)-proline benzyl ester-catalysed asymmetric aldol reactions in water. The reaction was carried out in a pH 7 buffered aqueous solution of cyclohexanone and a series of aryl aldehydes to provide anti aldol products in 7-89% ee. The aldol reaction between various ketone donors with 4-nitrobenzaldehyde under the same conditions were also developed to provide products in 13-61% ee.
Supervisor: Clarke, Paul Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available