Carbene-catalyzed dynamic kinetic resolutions and cycloaddition reactions via acylazolium intermediates

This thesis focuses on exploring the reactivity of N-heterocyclic carbene (NHC) catalyst-derived acylazolium intermediates. In particular, the thesis is mainly focused on NHC-catalyzed dynamic kinetic resolution (DKR) and cycloaddition reactions through formation of acylazolium intermediates. It con...

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Main Author: Song, Runjiang
Other Authors: Robin Yonggui Chi
Format: Thesis-Doctor of Philosophy
Language:English
Published: Nanyang Technological University 2022
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Online Access:https://hdl.handle.net/10356/154700
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spelling sg-ntu-dr.10356-1547002023-02-28T23:35:46Z Carbene-catalyzed dynamic kinetic resolutions and cycloaddition reactions via acylazolium intermediates Song, Runjiang Robin Yonggui Chi School of Physical and Mathematical Sciences robinchi@ntu.edu.sg Science::Chemistry This thesis focuses on exploring the reactivity of N-heterocyclic carbene (NHC) catalyst-derived acylazolium intermediates. In particular, the thesis is mainly focused on NHC-catalyzed dynamic kinetic resolution (DKR) and cycloaddition reactions through formation of acylazolium intermediates. It contains three chapters: Chapter 1 provides a brief review on the history and development of NHCs in organic catalysis. A number of classical reactive intermediates and key reaction modes in NHC catalysis are summarized. Literature studies closely related to the thesis work are introduced. Chapter 2 describes an NHC-catalyzed DKR and transesterification reaction for asymmetric synthesis of optically enriched α-aryloxycarboxylic esters with up to 99% yield and 99:1 er value. The facile interconversion between two NHC-activated diastereomeric acylazolium intermediates allows for highly efficient DKR to occur. The products from our strategy can readily undergo further transformations to produce chiral herbicides and other functional molecules. Chapter 3 presents a highly chemo- and enantioselective organocatalytic tandem reaction between hydroxylamines and bromoenals. The reaction provides access to isoxazolidin-5-ones in good yields and satisfactory enantioselectivities. Chapter 4 provides the conclusion and perspective of this thesis, including potential scientific and real-world applications derived from our study. Doctor of Philosophy 2022-01-06T03:20:23Z 2022-01-06T03:20:23Z 2022 Thesis-Doctor of Philosophy Song, R. (2022). Carbene-catalyzed dynamic kinetic resolutions and cycloaddition reactions via acylazolium intermediates. Doctoral thesis, Nanyang Technological University, Singapore. https://hdl.handle.net/10356/154700 https://hdl.handle.net/10356/154700 10.32657/10356/154700 en This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0). application/pdf Nanyang Technological University
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Science::Chemistry
spellingShingle Science::Chemistry
Song, Runjiang
Carbene-catalyzed dynamic kinetic resolutions and cycloaddition reactions via acylazolium intermediates
description This thesis focuses on exploring the reactivity of N-heterocyclic carbene (NHC) catalyst-derived acylazolium intermediates. In particular, the thesis is mainly focused on NHC-catalyzed dynamic kinetic resolution (DKR) and cycloaddition reactions through formation of acylazolium intermediates. It contains three chapters: Chapter 1 provides a brief review on the history and development of NHCs in organic catalysis. A number of classical reactive intermediates and key reaction modes in NHC catalysis are summarized. Literature studies closely related to the thesis work are introduced. Chapter 2 describes an NHC-catalyzed DKR and transesterification reaction for asymmetric synthesis of optically enriched α-aryloxycarboxylic esters with up to 99% yield and 99:1 er value. The facile interconversion between two NHC-activated diastereomeric acylazolium intermediates allows for highly efficient DKR to occur. The products from our strategy can readily undergo further transformations to produce chiral herbicides and other functional molecules. Chapter 3 presents a highly chemo- and enantioselective organocatalytic tandem reaction between hydroxylamines and bromoenals. The reaction provides access to isoxazolidin-5-ones in good yields and satisfactory enantioselectivities. Chapter 4 provides the conclusion and perspective of this thesis, including potential scientific and real-world applications derived from our study.
author2 Robin Yonggui Chi
author_facet Robin Yonggui Chi
Song, Runjiang
format Thesis-Doctor of Philosophy
author Song, Runjiang
author_sort Song, Runjiang
title Carbene-catalyzed dynamic kinetic resolutions and cycloaddition reactions via acylazolium intermediates
title_short Carbene-catalyzed dynamic kinetic resolutions and cycloaddition reactions via acylazolium intermediates
title_full Carbene-catalyzed dynamic kinetic resolutions and cycloaddition reactions via acylazolium intermediates
title_fullStr Carbene-catalyzed dynamic kinetic resolutions and cycloaddition reactions via acylazolium intermediates
title_full_unstemmed Carbene-catalyzed dynamic kinetic resolutions and cycloaddition reactions via acylazolium intermediates
title_sort carbene-catalyzed dynamic kinetic resolutions and cycloaddition reactions via acylazolium intermediates
publisher Nanyang Technological University
publishDate 2022
url https://hdl.handle.net/10356/154700
_version_ 1759853788078800896