| Autor: |
Aitken, R. Alan, Al-Awadi, Nouria A., Balkovich, Mark E., Bestmann, Hans Jürgen, Clem, Oliver, Gibson, Scott, Groß, Andreas, Kumar, Ajith, Röder, Thomas |
| Zdroj: |
European Journal of Organic Chemistry; March 2003, Vol. 2003 Issue: 5 p840-847, 8p |
| Abstrakt: |
Both ketone- and ester-stabilised phosphorus ylides undergo Michael addition to vinyl ketones to give the β,δ'-dioxo ylides 3 and 5, respectively, although in the latter case careful temperature control is required to avoid an undesired side-reaction. Under conditions of flash vacuum pyrolysis at 650 °C the ylides 3 generally undergo Ph3PO extrusion to afford the γ,δ-alkynyl ketones 14, although these are found to partly undergo a secondary fragmentation. In contrast, the ylides 5 react under the same conditions to give the synthetically useful 1,3-dienes 20 by way of cyclobutenes. Rate constants for the reaction of selected ylides 3 and 5 are reported. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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