A comparative analysis of the functionalisation of unactivated cycloalkanes using alkynes and either sunlight or a photochemical reactor

Using a standard mercury vapour lamp or sunlight, the synthetically difficult task of introducing functionality into unactivated cycloalkanes through C-C bond formation is accomplished in the presence of a soluble or supported photomediator and an alkyne bearing an electron-withdrawing group. The reaction involves the regiospecific addition of a photochemically generated cycloalkyl radical to the β-carbon of the alkyne. The use of solar radiation and a potentially recyclable polymer-bound photomediator for this fundamentally important synthetic process is particularly attractive from the clean/green chemistry perspective.