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Published on: March 25, 2017
Observable azacyclobutenone ylides with antiaromatic character from 2-diazoacetyl-azaaromatics
Nanyan Fu1, Annette D Allen, Shinjiro Kobayashi
1Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada.
Journal of the American Chemical Society
|April 25, 2007
Summary
New azacyclobutenone ylides were generated and characterized using laser flash photolysis. These novel compounds exhibit significant antiaromatic character in their four-membered rings and reduced aromaticity in their six-membered rings.
Area of Science:
- Organic Chemistry
- Photochemistry
- Physical Chemistry
Background:
- Azacyclobutenone ylides are reactive intermediates.
- Their generation and characterization are crucial for understanding novel chemical structures.
Purpose of the Study:
- To generate and characterize novel azacyclobutenone ylides.
- To investigate the electronic and aromatic properties of these ylides.
Main Methods:
- Laser flash photolysis of diazoacetylpyridine and diazoacetylpyridazine derivatives.
- Spectroscopic identification using IR and UV-Vis spectroscopy.
- Nuclear Magnetic Resonance (NMR) spectroscopy and computational NICS calculations.
Main Results:
- Successfully generated and identified azacyclobutenone ylides 2, 11, 14, 17, 19, and 21.
- Characterized by distinct IR and UV-Vis spectra, with ylide 21 showing notable persistence.
- Calculated NICS values and observed bond alternation suggest strong antiaromaticity in the four-membered rings and reduced aromaticity in the six-membered rings.
Conclusions:
- The study demonstrates the successful generation of novel azacyclobutenone ylides.
- These ylides possess unique electronic properties, indicating antiaromatic character.
- Findings contribute to the understanding of aromaticity and electronic structure in cyclic organic compounds.
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