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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| Format: | Thesis-Doctor of Philosophy |
| Language: | English |
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Nanyang Technological University
2022
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| Online Access: | https://hdl.handle.net/10356/154700 |
| _version_ | 1826113058723856384 |
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| author | Song, Runjiang |
| author2 | Robin Yonggui Chi |
| author_facet | Robin Yonggui Chi Song, Runjiang |
| author_sort | Song, Runjiang |
| collection | NTU |
| 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. |
| first_indexed | 2024-10-01T03:17:18Z |
| format | Thesis-Doctor of Philosophy |
| id | ntu-10356/154700 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T03:17:18Z |
| publishDate | 2022 |
| publisher | Nanyang Technological University |
| record_format | dspace |
| spelling | ntu-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 |
| spellingShingle | Science::Chemistry Song, Runjiang Carbene-catalyzed dynamic kinetic resolutions and cycloaddition reactions via acylazolium intermediates |
| title | 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_short | Carbene-catalyzed dynamic kinetic resolutions and cycloaddition reactions via acylazolium intermediates |
| title_sort | carbene catalyzed dynamic kinetic resolutions and cycloaddition reactions via acylazolium intermediates |
| topic | Science::Chemistry |
| url | https://hdl.handle.net/10356/154700 |
| work_keys_str_mv | AT songrunjiang carbenecatalyzeddynamickineticresolutionsandcycloadditionreactionsviaacylazoliumintermediates |