The asymmetric synthesis and reactions of α-functionalised organometallic reagents
This thesis describes the development of new methods for the asymmetric synthesis of α-alkoxy and α-amino organometallic reagents. Two approaches were taken: (i) sulfoxide → magnesium exchange; (ii) asymmetric lithiation-trapping using chiral bases. A review of this area is provided in Chapter One....
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ndltd-bl.uk-oai-ethos.bl.uk-5816942017-10-04T03:17:59ZThe asymmetric synthesis and reactions of α-functionalised organometallic reagentsRayner, PeterO'Brien, Peter2013This thesis describes the development of new methods for the asymmetric synthesis of α-alkoxy and α-amino organometallic reagents. Two approaches were taken: (i) sulfoxide → magnesium exchange; (ii) asymmetric lithiation-trapping using chiral bases. A review of this area is provided in Chapter One. Chapter Two details the synthesis of α-alkoxy sulfoxides A in 99:1 er by asymmetric lithiation using s-BuLi and chiral diamines and trapping with Andersen’s sulfinate. In addition, an investigation into the lack of stereospecificity at sulfur during the trapping process is presented. Finally, a sulfoxide → magnesium exchange was used to convert the α-alkoxy sulfoxides into α-alkoxy Grignard reagents B and subsequent trapping allows access to a range of products as single enantiomers. The remarkable configurational stability of α-alkoxy Grignard reagents when compared to their organolithium counterparts is of particular note. Attempts to use a similar method to synthesise α-amino sulfoxides in 99:1 er is described in Chapter Three. Furthermore, insights are given into the surprising instability of unsubstituted α-amino sulfoxides. Novel α-amino sulfoxides C were designed to prohibit sulfoxide elimination. From the isolatable α-amino sulfoxides, the synthesis and reactions of α-amino Grignard reagents D in 99:1 er via sulfoxide → magnesium exchange is reported. In Chapter Four, an investigation into the mechanism of the asymmetric lithiation trapping of N-thiopivaloyl azetidine E using s-BuLi and chiral diamines is presented. The configurational stability of the organolithium intermediate F was determined at −78°C and the scope of electrophilic trapping was investigated.547University of Yorkhttp://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.581694http://etheses.whiterose.ac.uk/4554/Electronic Thesis or Dissertation |
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547 Rayner, Peter The asymmetric synthesis and reactions of α-functionalised organometallic reagents |
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This thesis describes the development of new methods for the asymmetric synthesis of α-alkoxy and α-amino organometallic reagents. Two approaches were taken: (i) sulfoxide → magnesium exchange; (ii) asymmetric lithiation-trapping using chiral bases. A review of this area is provided in Chapter One. Chapter Two details the synthesis of α-alkoxy sulfoxides A in 99:1 er by asymmetric lithiation using s-BuLi and chiral diamines and trapping with Andersen’s sulfinate. In addition, an investigation into the lack of stereospecificity at sulfur during the trapping process is presented. Finally, a sulfoxide → magnesium exchange was used to convert the α-alkoxy sulfoxides into α-alkoxy Grignard reagents B and subsequent trapping allows access to a range of products as single enantiomers. The remarkable configurational stability of α-alkoxy Grignard reagents when compared to their organolithium counterparts is of particular note. Attempts to use a similar method to synthesise α-amino sulfoxides in 99:1 er is described in Chapter Three. Furthermore, insights are given into the surprising instability of unsubstituted α-amino sulfoxides. Novel α-amino sulfoxides C were designed to prohibit sulfoxide elimination. From the isolatable α-amino sulfoxides, the synthesis and reactions of α-amino Grignard reagents D in 99:1 er via sulfoxide → magnesium exchange is reported. In Chapter Four, an investigation into the mechanism of the asymmetric lithiation trapping of N-thiopivaloyl azetidine E using s-BuLi and chiral diamines is presented. The configurational stability of the organolithium intermediate F was determined at −78°C and the scope of electrophilic trapping was investigated. |
author2 |
O'Brien, Peter |
author_facet |
O'Brien, Peter Rayner, Peter |
author |
Rayner, Peter |
author_sort |
Rayner, Peter |
title |
The asymmetric synthesis and reactions of α-functionalised organometallic reagents |
title_short |
The asymmetric synthesis and reactions of α-functionalised organometallic reagents |
title_full |
The asymmetric synthesis and reactions of α-functionalised organometallic reagents |
title_fullStr |
The asymmetric synthesis and reactions of α-functionalised organometallic reagents |
title_full_unstemmed |
The asymmetric synthesis and reactions of α-functionalised organometallic reagents |
title_sort |
asymmetric synthesis and reactions of α-functionalised organometallic reagents |
publisher |
University of York |
publishDate |
2013 |
url |
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.581694 |
work_keys_str_mv |
AT raynerpeter theasymmetricsynthesisandreactionsofafunctionalisedorganometallicreagents AT raynerpeter asymmetricsynthesisandreactionsofafunctionalisedorganometallicreagents |
_version_ |
1718543168437223424 |