Preparation of C 2-Symmetric Biaryl Bisiminium Salts and Their Use as Organocatalysts for Asymmetric Epoxidation

The research in this thesis depicts some of the most current developments in the area of asymmetric epoxidation of alkenes using chiral iminium salt catalysts. The first chapter reviews past and present developments in; catalytic asymmetric epoxidation, and covers the application of this reaction towards the kinetic resolution of racemic olefins.Chapter two is separated into two key areas; (i) asymmetric epoxidation as a tool in the kinetic resolution of racemic chromene substrates, and (ii) investigations into the asymmetric epoxidation of new N-protected dihydroquinoline substrates. In the first part of chapter two, the first examples of kinetic resolution in epoxidation reactions using iminium salt catalysts are reported, providing up to 98% ee in the epoxidation of racemic cis-chromenes.The second part of chapter two details the first known examples of asymmetric epoxidation upon nitrogen-protected dihydroquinoline substrates, affording enantioselectivities as high as 73% ee.In both parts of chapter two, non-aqueous epoxidation conditions were employed using Page's dihydroisoquinolinium iminium salt catalyst. The later part of chapter two introduces a biphenylazepinium iminium salt catalyst used under aqueous epoxidation conditions. Chapter three includes experimental data for all the compounds mentioned in chapter two, with chapter four containing HPLC traces to show determination of enantiomeric excess of epoxides, and enantioenriched alkene traces.iii ACKNOWLEDGEMENTS

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Seven-Membered Rings

Meyer

Bissember

Hyland

et al. 2017

Progress in Heterocyclic Chemistry

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Preparation of C 2-Symmetric Biaryl Bisiminium Salts and Their Use as Organocatalysts for Asymmetric Epoxidation

Abstract: 2 BPh 4 N up to 55% ee iminium salt (5 mol%) Oxone (2 equiv) NaHCO 3 (5 equiv) MeCN-H 2 O (10:1) 0 °C, 2 h O

Cited by 5 publications

References 10 publications

ChemInform Abstract: Preparation of C₂‐Symmetric Biaryl Bisiminium Salts and Their Use as Organocatalysts for Asymmetric Epoxidation.

ChemInform Abstract: Preparation of C₂‐Symmetric Biaryl Bisiminium Salts and Their Use as Organocatalysts for Asymmetric Epoxidation.

Recent Advances in Iminium‐Salt‐Catalysed Asymmetric Epoxidation

Seven-Membered Rings

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Preparation of C 2-Symmetric Biaryl Bisiminium Salts and Their Use as Organocatalysts for Asymmetric Epoxidation

Abstract: 2 BPh 4 N up to 55% ee iminium salt (5 mol%) Oxone (2 equiv) NaHCO 3 (5 equiv) MeCN-H 2 O (10:1) 0 °C, 2 h O

Cited by 5 publications

References 10 publications

ChemInform Abstract: Preparation of C2‐Symmetric Biaryl Bisiminium Salts and Their Use as Organocatalysts for Asymmetric Epoxidation.

ChemInform Abstract: Preparation of C2‐Symmetric Biaryl Bisiminium Salts and Their Use as Organocatalysts for Asymmetric Epoxidation.

Recent Advances in Iminium‐Salt‐Catalysed Asymmetric Epoxidation

Seven-Membered Rings

Contact Info

Product

Resources

About

ChemInform Abstract: Preparation of C₂‐Symmetric Biaryl Bisiminium Salts and Their Use as Organocatalysts for Asymmetric Epoxidation.

ChemInform Abstract: Preparation of C₂‐Symmetric Biaryl Bisiminium Salts and Their Use as Organocatalysts for Asymmetric Epoxidation.