Photocycloaddition of enynones (4-acylbut-1-en-3-ynes) to alkenes.
The title compounds undergo regio- and diastereoselective [2+2]-cycloaddition at the olefinic C-C bond on irradiation (350 nm) in the presence of either methacrylonitrile or 2,3-dimethylbuta-1,3-diene, affording hitherto unknown 1-cyclobutylalk-1-yn-3-ones or 1-bicyclo[4.2.0]octylalk-1-yn-3-ones, respectively.
Inhülsen
Inga
I
Chemistry Department, University of Hamburg, D-20146 Hamburg, Germany.
Margaretha
Paul
P