ORGN 459 |
| We present cationic Rh(I)-catalyzed mild intramolecular [4+2] cycloadditions of ester-tethered diene-yne substrates, which generally show low Diels-Alder reactivity under themal conditions due to the intrinsic nature (transoid vs cisoid) of the ester functional group. The cationic Rh(I) species, which is derived from [Rh(COD)Cl]2 and AgSbF6, and the use of fluorinated alcohols as a solvent efficiently catalyzed intramolecular [4+2] cycloaddition reactions of ester-tethered 1,3-diene-8-yne compounds such as 2-propynyl penta-2,4-dienoate and 2,4-pentadienyl propiolate derivatives. The cationic Rh(I) catalyst-fluorinated alcohols system was also effective in intramolecular [5+2] cycloaddition reactions of ester-tethered vinylcyclopropane-alkyne compounds. We discuss the scope and limitations of the present catalytic system.
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Modern Acetylene Chemistry
8:00 PM-10:00 PM, Tuesday, 12 September 2006 Moscone Center -- Hall D, Poster
Division of Organic Chemistry |
