Photochemical Formation of [3,3,2]Propellanes from 1,5-Dimethylenecycloalkanes

Abstract

Photolysis of the dienes 10,13-imethylenetricyclo[6,3,3,0^2,7]tetradeca-2,4,6-triene and 1,5-dimethylenecyclooctane results in cyclization to the corresponding [3,3,2]propellane structure. The latter reaction provides a convenient synthesis of [3,3,2]propellane from cycloocta-1,5-diene. In contrast 2,6-dimethylenebicyclo[3,3,1]nonane is converted into 2-methyl-6-methylenebicyclo[3,3,1]non-2-ene under similar conditions.