ORGN 529 |
| The formation of biaryls is an important synthesis in organic chemistry. There have been a variety of synthetic methods, from the classic Ullmann or Gomberg-Bachmann reactions to the most common Suzuki coupling, which generate biaryls in moderate to good yields. However, there are problems with the methodologies, including the need to make specific precursors as well as functional group compatibility in the reactions. It has been shown that N-aromatic nitrosamides can decompose in benzene to give biaryls. The method originally developed by Grieve and Hey in generating nitrosamides from N-aromatic acetamides was modified and applied in our work to achieve milder conditions and avoid the isolation of nitrosamide intermediates, which are carcinogens, while maintaining its moderate to good yields. In our approach, N-aromatic nitrosamides were generated in situ from acetamides at 0°C in AcOH/Ac2O using NaNO2 before being allowed to react with a reactive aromatic solvent such as benzene on warming to room temperature. The reactive solvent is used as the extraction solvent in the workup. The method has demonstrated equal or better yields of biaryls (53-81% isolated yields) compared to Grieve and Hey's work, as well as good functional group compatibility. In summary, the method of the formation of biaryls is inexpensive, simple and convenient, and tolerant of a variety of functional groups. |
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Heterocycles, Aromatics, Metal-Mediated Reactions and Syntheses, Materials, Devices, and Switches
8:00 PM-10:00 PM, Wednesday, 29 March 2006 Georgia World Congress Center -- Ex. Hall B4, Poster
Division of Organic Chemistry |