Iron-catalyzed electrochemical C–H perfluoroalkylation of arenes

Abstract

A new iron-catalyzed reaction for the coupling of perfluoroalkyl iodides (RFI) with aromatic substrates is described. The perfluoroalkylated arene products are obtained in good to excellent yields in the presence of a [(bpy)Fe(ii)] catalyst (10%) electrochemically regenerated or generated from [(bpy)Fe(iii)] at room temperature. The development, scope, and preliminary mechanistic studies of these transformations are reported.

General C(sp2)–C(sp3) Cross-Electrophile Coupling Reactions Enabled by Overcharge Protection of Homogeneous Electrocatalysts

“…Illustrated in Figure c, CV of complex 4 in the presence of added alkyl electrophile reveals a reduction event with a catalytic current at the precise potential of the electrochemical reaction. Reduction of analogous nickel halides is known to generate low-valent metal centers that mediate rapid halogen abstraction from alkyl halides to form carbon-centered radicals. ,− The resulting radical is likely captured by the Ni­(aryl) complex 2 and subsequently coupled to the aryl fragment. , Radical clock experiments reveal trapping of the radical to be dependent on the concentration of Ni in solution, which is consistent with a bimetallic mechanism for electrophile activation and coupling (see the SI, Figure S4). ,, Overall, these data reveal that while a cathodic potential of −1.9 V must be reached for effective XEC coupling, the Ni­(aryl) intermediate is susceptible to rapid decomposition from reduction at potentials below −2 V.…”

Noble metal-free bis-tridentate benzimidazole zinc(ii) and iron(ii) complexes for selective CO2photoreduction

“…4, an EPR signal at g = 2.003 was observed when the solution was irradiated for 3 min, which was similar to other pyridine-containing organic radicals. 54,55 Hence, the generation of radical anions is mostly probable during photocatalysis. However, elucidating the interaction between ligand-based radical anion and CO 2 should be further conducted by more methods.…”

External oxidant-free cross-coupling: electrochemically induced aromatic C–H phosphonation of azoles with dialkyl-H-phosphonates under silver catalysis

“…Thus, new electrochemical reactions of the C(sp 2 )-H phosphorylation [20][21][22][23][24][25][26][27] have been proposed in recent years. The progress of electroorganic synthesis in this field is described in numerous reviews 22,23,[28][29][30][31][32] and papers concerning some recent advances in C-H functionalization, such as fluoroalkylation, [33][34][35][36][37][38] amination, [39][40][41][42] aziridination, 43 oxygenation, [44][45][46] arylation, 47 alkylation, 48 amino-oxygenation, 49 etc. The first electrochemical oxidative phosphorylation of benzoxazoles in the presence of a 3d metal catalyst was reported in 2016.…”