Aryl and alkyl beta-heteroatom-trisubstituted vinyl triflones react with THF and cyclohexane to undergo trifluoromethyl radical-mediated C-H functionalization reactions to afford E and Z beta-heteroatom-trisubstituted olefins. Most reactions proceed with both high yield and high stereospecificity (retention of configuration). beta-Substituents which have been employed in this study are iodine, bromine, fluorine, benzoate, ethylcarbonate, and phthalimide. beta-Substituents bearing powerful electron-releasing groups such as alkoxy or amino render the vinyl triflone unreactive.