Studies on fluoroalkylation and fluoroalkoxylation. Part 10. Electron-transfer induced reactions of perfluoroalkyl iodides and the dialkyl malonate anion and β-fragmentation of the halotetrafluoroethyl radical

Fluoroalkyl iodides, XCF2CF2I (X=F, perfluoroalkyl group) (1), react readily with malonic ester anion (2) in DMF to give (3), 1-hydroperfluoroalkane (4) and dimer of the anion (5). The reaction is accelerated by UV irradiation and partly suppressed by p-DNB. Diallyl ether (DAE) can trap the radical intermediates to afford five-membered ring products. Interestingly, in the case of 1 ( X = Cl, I ) the same reaction mainly yielded tetrafluoroethylene and 5 instead of 3 and 4. The radical intermediate XCF2CF·2 ( X=Cl ) can also be trapped by DAE to yield tetrahydrofuran derivatives. All these results can be rationalized in terms of the SRN1 mechanism.