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Continuous Flow Chemistry: Reaction of Diphenyldiazomethane with p-Nitrobenzoic Acid
Published on: November 15, 2017
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Chemoenzymatic Dynamic Kinetic Resolution of Amines in Fully Continuous-Flow Mode
Emese Farkas1, Márk Oláh1, Attila Földi1
1Department of Organic Chemistry and Technology , Budapest University of Technology and Economics , Műegyetem rkp. 3 , H-1111 Budapest , Hungary.
Organic Letters
|December 14, 2018
Summary
This study presents a novel continuous-flow system for lipase-mediated dynamic kinetic resolution of benzylic amines. The process achieves moderate to good yields with excellent enantiomeric purity using immobilized enzymes and catalysts.
Area of Science:
- Biocatalysis and organic synthesis
- Flow chemistry applications
- Enzyme immobilization techniques
Background:
- Dynamic kinetic resolution (DKR) is crucial for synthesizing enantiopure compounds.
- Continuous-flow systems offer advantages in process control and scalability for chemical reactions.
- Lipase B from Candida antarctica is a versatile biocatalyst for esterification and amidation reactions.
Purpose of the Study:
- To develop and demonstrate a fully continuous-flow system for lipase-mediated DKR of benzylic amines.
- To optimize reaction conditions for yield and enantioselectivity in the flow system.
- To investigate the use of immobilized enzymes and heterogeneous racemization catalysts in flow.
Main Methods:
- Utilized sol-gel immobilized lipase B from Candida antarctica as the biocatalyst.
- Employed palladium on 3-aminopropyl-functionalized silica as the racemization catalyst.
- Conducted the DKR of benzylic amines in a continuous-flow reactor using isopropyl 2-ethoxyacetate as the acylating agent, ammonium formate as hydrogen/nitrogen source, and 2-methyl-2-butanol as solvent under regulated pressure.
Main Results:
- Achieved moderate to good yields for the DKR of various benzylic amines (1a-g).
- Obtained excellent enantiomeric excesses in the synthesized products.
- Demonstrated the feasibility and efficiency of the fully continuous-flow DKR system.
Conclusions:
- The developed continuous-flow system enables efficient lipase-mediated DKR of benzylic amines.
- The combination of immobilized enzymes and heterogeneous catalysts is effective in a flow setup.
- This approach offers a scalable and sustainable method for producing enantiopure benzylic amines.
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