Regio- and stereoselective cyclization reactions of unsaturated silyl enol ethers by photoinduced electron transfer - Mechanistic aspects and synthetic approach

Hintz S, Mattay J, van Eldik R, Fu WF (1998)
European Journal of Organic Chemistry (8): 1583-1596.

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Zeitschriftenaufsatz | Veröffentlicht | Englisch
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Abstract / Bemerkung
Oxidative photoinduced electron transfer (PET) reactions have been performed with various silyl enol ethers and silyloxy-2H-chromones bearing an olefinic or silylacetylenic side chain, The reactions result in regioselective ring closure with the formation of bi- to tetracyclic ring systems with a well-defined ring juncture, e.g. perhydrophenanthrenones 13 or benzo-annellated xanthenones 24. Our investigations have focussed on the optimization of this cyclization method with regard to irradiation time and product yield. The irradiation times could be reduced by using the cosensitized PET method. Modifying the substrate at the silyl group led to enhanced yields. In addition, we found that solvent and pressure dependences are important tools, allowing control of the regiochemistry. Both the synthesis of 6-endo products by radical cationic reaction pathways, as well as 5-exo ring closure by radical intermediates was achieved. Mechanistic details, including findings from deuterium labelling experiments, are discussed.
Erscheinungsjahr
Zeitschriftentitel
European Journal of Organic Chemistry
Zeitschriftennummer
8
Seite
1583-1596
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Hintz S, Mattay J, van Eldik R, Fu WF. Regio- and stereoselective cyclization reactions of unsaturated silyl enol ethers by photoinduced electron transfer - Mechanistic aspects and synthetic approach. European Journal of Organic Chemistry. 1998;(8):1583-1596.
Hintz, S., Mattay, J., van Eldik, R., & Fu, W. F. (1998). Regio- and stereoselective cyclization reactions of unsaturated silyl enol ethers by photoinduced electron transfer - Mechanistic aspects and synthetic approach. European Journal of Organic Chemistry(8), 1583-1596.
Hintz, S., Mattay, J., van Eldik, R., and Fu, W. F. (1998). Regio- and stereoselective cyclization reactions of unsaturated silyl enol ethers by photoinduced electron transfer - Mechanistic aspects and synthetic approach. European Journal of Organic Chemistry, 1583-1596.
Hintz, S., et al., 1998. Regio- and stereoselective cyclization reactions of unsaturated silyl enol ethers by photoinduced electron transfer - Mechanistic aspects and synthetic approach. European Journal of Organic Chemistry, (8), p 1583-1596.
S. Hintz, et al., “Regio- and stereoselective cyclization reactions of unsaturated silyl enol ethers by photoinduced electron transfer - Mechanistic aspects and synthetic approach”, European Journal of Organic Chemistry, 1998, pp. 1583-1596.
Hintz, S., Mattay, J., van Eldik, R., Fu, W.F.: Regio- and stereoselective cyclization reactions of unsaturated silyl enol ethers by photoinduced electron transfer - Mechanistic aspects and synthetic approach. European Journal of Organic Chemistry. 1583-1596 (1998).
Hintz, S, Mattay, Jochen, van Eldik, R, and Fu, WF. “Regio- and stereoselective cyclization reactions of unsaturated silyl enol ethers by photoinduced electron transfer - Mechanistic aspects and synthetic approach”. European Journal of Organic Chemistry 8 (1998): 1583-1596.