[1.1.1]Propellane: Reaction with free radicals

[1.1.1]Propellane is more reactive towards free radicals than bicyclo[1.1.0]butane, and much more reactive than bicyclo[2.1.0]pentane. Therefore, the reactivity is not determined by strain energy relief or the HOMO energy. The addition of acetaldehyde is unique in that a 1:2 adduct is formed. A number of other additions are described, and provide convenient routes to 1,3-disubstituted bicyclo[1.1.1]pentanes.