Photocycloadditions in disparate chemical environments.

We elucidate the wavelength dependence of a photocycloaddition by (i) accessing action plots dependent on the reactivity relative to the number of absorbed photons, (ii) establishing the effect on substrate concentration on photochemical reactivity and (iii) determining wavelength-dependent reactivity as a function of the solvent environment, comparing acetonitrile with dimethyl sulfoxide.