COPPER (I) CATALYSIS OF OLEFIN PHOTOREACTIONS -9. PHOTOBICYCLIZATION OF alpha -, beta -, AND gamma -ALKENYLALLYL ALCOHOLS.

Article abstract of DOI:10.1021/ja00368a014

Cyclobutylcarbinyl alcohols of the bicyclo left bracket 3. 2. 0 right bracket heptane ring system are produced by UV irradiation of alpha -, beta -, and gamma -alkenylallyl alcohols in the presence of copper (I) trifluoromethanesulfonate (CuOTf). endo-2-Hydroxy epimers of bicyclo left bracket 3. 2. 0 right bracket heptan-2-ols are generated stereoselectively. This result as well as the effect of CuOTf on the **1H NMR spectrum of 4,4-dimethyl-1,6-heptadien-3-ol suggests that coordination of two C equals C bonds and the hydroxyl group with a single copper (I) is important. The derived bicyclo left bracket 3. 2. 0 right bracket heptan 2-ones fragment cleanly at 580 degree C to afford cyclopent-2-en-1-ones. Geometric isomerization competes with photobicyclization of (E)- and (Z)-octa-2,7-dien-1-ols.