A simple, modular synthesis of substituted pyridines
Songbai Liu1, Lanny S Liebeskind
1Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, USA.
Journal of the American Chemical Society
|May 10, 2008
Summary
A new modular method synthesizes highly substituted pyridines using a copper-catalyzed cascade reaction. This efficient process involves cross-coupling, electrocyclization, and air oxidation, yielding pyridines in good to excellent amounts.
Area of Science:
- Organic Chemistry
- Synthetic Chemistry
- Heterocyclic Chemistry
Background:
- Pyridines are crucial heterocyclic compounds in pharmaceuticals and materials science.
- Efficient synthesis of highly substituted pyridines remains a challenge in organic chemistry.
Purpose of the Study:
- To develop a simple, modular, and efficient method for preparing highly substituted pyridines.
- To explore a novel cascade reaction for pyridine synthesis.
Main Methods:
- A three-step cascade reaction involving N-iminative copper-catalyzed cross-coupling, electrocyclization, and air oxidation.
- Utilized alkenylboronic acids and alpha,beta-unsaturated ketoxime O-pentafluorobenzoates as starting materials.
- Demonstrated good functional group tolerance with readily available starting materials.
Main Results:
- Achieved moderate to excellent isolated yields (43-91%) of highly substituted pyridines.
- The cascade reaction proceeded efficiently, forming the pyridine core in a single operation.
- The method proved to be versatile, accommodating a range of functional groups.
Conclusions:
- The disclosed method provides a straightforward and modular approach to highly substituted pyridines.
- This novel cascade reaction offers a valuable tool for synthetic chemists.
- The high yields and functional group tolerance make this method attractive for various applications.
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