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Published on: August 17, 2016
Chiral lithium binaphtholate aqua complex as a highly effective asymmetric catalyst for cyanohydrin synthesis
Manabu Hatano1, Takumi Ikeno, Takashi Miyamoto
1Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8603, Japan.
Journal of the American Chemical Society
|August 4, 2005
Summary
A new catalytic system using chiral lithium complexes enables highly enantioselective synthesis of aromatic cyanohydrins. This cost-effective method is suitable for large-scale production, offering improved stereochemistry compared to dry systems.
Area of Science:
- Organic Chemistry
- Catalysis
- Asymmetric Synthesis
Background:
- Cyanohydrins are versatile synthetic intermediates.
- Enantioselective synthesis is crucial for pharmaceuticals and fine chemicals.
- Existing methods for enantioselective cyanohydrin synthesis can be complex or costly.
Purpose of the Study:
- To develop a highly enantioselective and cost-effective method for synthesizing aromatic cyanohydrins.
- To investigate the use of chiral lithium binaphtholate complexes as catalysts.
- To compare the performance of aqua/alcohol complexes with "dry" catalytic systems.
Main Methods:
- Development of chiral lithium binaphtholate aqua or alcohol complexes.
- Application of these complexes as catalysts in the reaction of aromatic aldehydes with cyanide sources.
- Gram-scale synthesis of cyanohydrins.
- Analysis of enantiomeric excess and absolute stereochemistry of the products.
Main Results:
- Achieved highly enantioselective cyanohydrin synthesis with aromatic aldehydes.
- Demonstrated the catalyst's suitability for process chemistry and gram-scale production.
- Observed significant improvements in enantiomeric excess compared to previous methods.
- Noted an interesting changeover in absolute stereochemistry with the new catalytic systems.
Conclusions:
- Chiral lithium binaphtholate aqua or alcohol complexes provide a simple, inexpensive, and effective catalyst for enantioselective cyanohydrin synthesis.
- The developed method is suitable for industrial applications and gram-scale synthesis.
- The use of aqua or alcohol ligands leads to distinct stereochemical outcomes compared to anhydrous systems.
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