Radical Alkynyltrifluoromethylation of Alkenes Initiated by an Electron Donor–Acceptor Complex

Radical alkynyltrifluoromethylation of alkenes with actylenic triflones has been achieved. This radical chain reaction is initiated by a catalytic amount of an electron-donor-acceptor complex composed of Togni's reagent and N-methylmorpholine. This transformation proceeds under exceptionally mild and operationally simple conditions. A variety of alkenes are compatible in this protocol including aliphatic alkenes, vinyl ethers, enecarbamates, styrenes, and even acrylates, providing diverse β- trifluoromethyl alkynes in good to excellent yields.