ORGN 285 |
| Verdazyl radicals have recently been used to control the polymerization of styrene and acrylate monomers by taking advantage of the fact that these radicals do not react with the double bonds of these monomers to initiate polymerization. However, the chemistry of verdazyl radicals has not been extensively studied. We have found that verdazyl radical 1 is readily transformed into an azomethine imine, which undergoes cycloaddition reactions with dipolarophiles to produce unique heterocyclic structures. However, when the ketene equivalent dipolarophile, 1 chloroacrylonitrile, was reacted with 1, the unexpected major product was 2, the addition product of 1 to the 1 chloroacrylonitrile double bond to form a captodative radical, probably the driving force for the reaction, followed by elimination of HCl. In this presentation we will demonstrate the scope of this reaction as it pertains to various 1,1-disubstituted olefins containing electron-withdrawing and electron-donating substituents, rationalize the Z-configuration and show whether the reaction can be extended to the nitroxide family of stable radicals.
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Heterocycles and Aromatics
8:00 AM-11:40 AM, Tuesday, April 8, 2008 Morial Convention Center -- Rm. R06, Oral
Division of Organic Chemistry |
