Eco-efficient electrocatalytic C–P bond formation

Abstract

The development of practical, efficient and atom-economical methods of formation of carbon-phosphorus bonds remains a topic of considerable interest for the current synthetic organic chemistry and electrochemistry. This review summarizes selected topics from the recent publications with particular emphasis on phosphine and phosphine oxides formation from white phosphorus, chlorophosphines in electrocatalytic processes using aryl, hetaryl or perfluoroalkyl halides as reagents. This review includes selected highlights concerning recent progress in modification of catalytic systems for aromatic C–H bonds phosphonation involving metal-catalyzed ligand directed or metal-induced oxidative processes. Furthermore, a part of this review is devoted to phosphorylation of olefins with white phosphorus under reductive conditions in water-organic media. Finally, we have also documented recent advances in ferrocene C–H activation and phosphorylation.

Redox-Induced Aromatic C–H Bond Functionalization in Metal Complex Catalysis from the Electrochemical Point of View

“…From the viewpoint of implementation, electrochemical reactions have several advantages: mild conditions, high rates, selectivity, and convenient operational control through switching current density and potential. Electrochemical methods can be recommended for the preventive protection of the environment, because they do not require any special reagents [13][14][15][16][17][18][19][20][21][22][23][24][25][102][103][104].…”

“…Also, ligand-directed substitution at the C-H bond in 2-phenylpyridine, which was earlier employed for acetoxylation and perfluoroalkylation under electrochemical conditions [23,24] in the presence of Pd(II) acetate, proved to be effective in the case of phosphorylation [13][14][15]25]. The introduction of the phosphonate group is based on the electrochemical oxidation of a mixture of palladium acetate, phenylpyridine, and diethyl phosphite at room temperature, with phenylpyridine orto-phosphonate being obtained without special external oxidants (Scheme 10).…”

“…presence of Pd(II) acetate, proved to be effective in the case of phosphorylation [13][14][15]25]. The introduction of the phosphonate group is based on the electrochemical oxidation of a mixture of palladium acetate, phenylpyridine, and diethyl phosphite at room temperature, with phenylpyridine orto-phosphonate being obtained without special external oxidants (Scheme 10).…”

“…In most cases, however, oxidative C-H transformations still rely on the presence of super-stoichiometric amounts of oxidants, which can be problematic in terms of functional group tolerance, waste generation, and cost. Electrochemical oxidation can be a cheaper, greener, and more controllable alternative to these oxidative reactions [13][14][15][16][17][18][19][20][21][22][23][24][25].…”

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.…”