A metal-free picolinamide assisted electrochemical ortho-trifluoromethylation of arylamines

Review and Theoretical Analysis of Fluorinated Radicals in Direct CAr-H Functionalization of (Hetero)arenes

We highlight key contributions in the field of direct radical CAr- H (hetero)aromatic functionalization involving fluorinated radicals. A compilation of Functional Group Transfer Reagents and their diverse activation mechanisms leading to the release of radicals are discussed. The substrate scope for each radical is analyzed and classified into three categories according to the electronic properties of the substrates. Density functional theory computational analysis provides insights into the chemical reactivity of several fluorinated radicals through their electrophilicity and nucleophilicity parameters. Theoretical analysis of their reduction potentials also highlights the remarkable correlation between electrophilicity and oxidizing ability. It is also established that highly fluorinated radicals (e.g. ⋅OCF3) are capable of engaging in single-electron transfer (SET) processes rather than radical addition, which is in good agreement with experimental literature data. A reactivity scale, based on activation barrier of addition of these radicals to benzene is also elaborated using the high accuracy DLPNO-(U)CCSD(T) method.

Transition-metal-free electrochemical oxidative C(sp2)-H trifluoromethylation of aryl aldehyde hydrazones

A simple protocol of metal-free C-H trifluoromethylation of hydrazones via electrolysis was developed. This environment-friendly transformation showed high efficiency, good tolerance, and scaled-up functionalization, providing the desired products in moderate to good yields. At the same time, a high yield can be obtained for the substrates either bearing an electron-donating group or an electron-withdrawing group by using different trifluoromethyl reagents. In addition, the radical mechanism was confirmed by the control experiment.

Fe-catalyzed hydroxytrifluoromethylation of α-(trifluoromethyl)styrenes with CF3SO2Na: facile access to α,β-bistrifluoromethyl tertiary alcohols

A mild and practical Fe-catalyzed hydroxytrifluoromethylation of α-(trifluoromethyl)styrenes with CF₃SO₂Na in the presence of K₂S₂O₈ and air was developed. The reaction proceeded efficiently at room temperature without β-fluoride elimination and afforded the corresponding α,β-bistrifluoromethyl tertiary alcohols in good to excellent yields.