Photocycloadditionen von 2-donorsubstituierten Propennitrilen an Cumarinderivate - Photocycloadditions of 2-donor substituted propenenitriles to coumarin derivatives

by Neubauer, Stefan

Abstract (Summary)
Reactions of photoexcited coumarins and their thia analogues with captodative alkenes have been investigated, with special emphasis on the nature of the excited states and the specific influence of the substrates on regio- and stereoselectivity of the observed [2+2]-photocycloadditions. Aside of two coumarin thiones all coumarins investigated regioselectively add captodative alkenes at the pyranone moeity giving rise to head-to-tail [2+2]-photocycloadducts with donor-endo adducts as prevailing isomers. The observed regio- and stereoselectivities can be best explained if a 1,4-biradical is assumed as intermediate in the photocycloaddition.
Bibliographical Information:

Advisor:Prof. Dr. Dietrich Döpp

School:Universität Duisburg-Essen, Standort Essen

School Location:Germany

Source Type:Master's Thesis

Keywords:chemie gerhard mercator universitaet


Date of Publication:05/22/2001

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