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Sulfonium ylide epoxidation reactions: methylene transfer
Benjamin R Bellenie1, Jonathan M Goodman
1Unilever Centre for Molecular Science Informatics, Department of Chemistry, Lensfield Road, Cambridge, UK CB2 1EW.
Chemical Communications (Cambridge, England)
|April 30, 2004
Summary
Chiral sulfides derived from D-mannitol efficiently create terminal epoxides with high enantioselectivity. This study introduces the first double asymmetric induction in sulfonium methylide epoxidation, alongside an improved ylide generation method.
Area of Science:
- Organic Chemistry
- Asymmetric Synthesis
- Catalysis
Background:
- Epoxides are crucial synthetic intermediates.
- Asymmetric epoxidation is vital for producing enantiomerically pure compounds.
- Sulfonium ylides are effective reagents for epoxidation.
Purpose of the Study:
- To develop a novel method for synthesizing chiral epoxides.
- To achieve double asymmetric induction in sulfonium methylide epoxidation.
- To improve the generation of sulfonium ylides for enhanced efficiency.
Main Methods:
- Utilizing a D-mannitol derived chiral sulfide as a catalyst precursor.
- Employing sulfonium methylide chemistry for epoxidation reactions.
- Optimizing reaction conditions for improved yields and enantioselectivity.
Main Results:
- Terminal epoxides were synthesized with up to 76% enantiomeric excess (ee).
- The first successful demonstration of double asymmetric induction in this reaction class was achieved.
- An improved protocol for generating sulfonium ylides was developed, enhancing accessibility and reactivity.
Conclusions:
- The D-mannitol derived chiral sulfide provides an effective route to enantiomerically enriched terminal epoxides.
- This work represents a significant advancement in asymmetric epoxidation methodology.
- The improved ylide generation method broadens the applicability of sulfonium ylide chemistry.