Electrochemically driven regioselective C-H phosphorylation of group 8 metallocenes

Recent advances in the electrochemical synthesis of organophosphorus compounds

In this review, we describe recent advances in electrochemical green methods for the synthesis of various organophosphorus compounds through the formation of phosphorus-carbon, phosphorus-nitrogen, phosphorus-oxygen, phosphorus-sulfur, and phosphorus-selenium bonds. The impact of different electrodes is also discussed in this matter. Graphite, platinum, RVC, and nickel electrodes have been used extensively for the electrochemical synthesis of organophosphorus compounds. The recent advances in the electrochemical synthesis of organophosphorus compounds have made this method a promising method for preparing various structures. This review is an introduction to encourage scientists to use electrosynthesis as a green, precise, and low-cost method to prepare phosphorous structures.

Potassium Phosphate-Mediated Synthesis of C4-Phosphorylated Quinolines via Cascade Cycloisomerization of Ynones

A cascade phosphorylation cycloisomerization of readily accessible ynones and diphenylphosphine oxides facilitated by potassium phosphate is described, allowing for the straightforward synthesis of C4-phosphorylated quinoline scaffolds. The formation of a C-P bond and a C-N bond is achieved in a single procedure without the need for pre-assembled quinoline cores prior to phosphorylation. This transformation operates without the requirement for metals or oxidants and exhibits excellent compatibility with various functional groups. Furthermore, antimicrobial activity evaluation demonstrated that the synthesized C4-phosphorylated quinoline derivatives exhibited potent inhibitory activity against Staphylococcus aureus.

Selective Synthesis of Mono- and Bis-Phosphorylated (Dihydro)pyrans via TMSCl-Mediated Cascade Phosphorylation Cycloisomerization of Enynones

A chlorotrimethylsilane (TMSCl)-mediated cascade phosphorylation and cycloisomerization of enynones with diphenylphosphine oxides is presented. This methodology enables the highly selective synthesis of monophosphorylated 2H-pyrans and bisphosphorylated dihydropyrans through precise solvent-reagent stoichiometry control. The strategy demonstrated excellent functional group compatibility and high yields (up to 96%), providing facile access to structurally diverse phosphorylated heterocycles with potential applications in medicinal chemistry and materials science.

NaIO4/air-initiated phosphorylation of alcohols with H-phosphine oxides for the construction of P(O)-O bonds in water

A facile and efficient protocol for P(O)-O bond formation was discovered through NaIO4/air-initiated phosphorylation of alcohols with H-phosphine oxides in water. This reaction showed good functional group tolerance and a broad substrate scope, providing an alternative method for constructing P(O)-O bonds. Mechanistic studies suggested that a phosphoryl radical-involving process from H-phosphine oxides facilitated the phosphorylation of alcohols under air.

Electrochemical Synthesis of Phosphorylated Indoles and Trp-Containing Oligopeptides

Cp2Fe-mediated electrochemical synthesis of phosphorylated indoles and Trp-containing oligopeptides has been developed, which eliminates the need for external oxidants and yields the desired products in moderate to excellent yields under mild conditions. Importantly, the synthetic applicability was further demonstrated through its easy scalability and the anticancer activity of the product. Remarkably, it presents the first electrochemical protocol to access the phosphorylation of indoles and Trp-containing oligopeptides.

Electrochemical N-Aroylation of Sulfoximines by Using Benzoyl Hydrazines with H2 Generation

Developed here is a robust electrochemical cross-coupling reaction between aroyl hydrazine and NH-sulfoximine via concomitant cleavage and formation of C(sp2 )-N bonds with the evolution of H2 and N2 as innocuous by-products. This sustainable protocol avoids the use of toxic reagents and occurs at room temperature. The reaction proceeds via the generation of an aroyl and a sulfoximidoyl radical via anodic oxidation under constant current electrolysis (CCE), affording N-aroylated sulfoximine. The strategy is applied to late-stage sulfoximidation of L-menthol, (-)-borneol, D-glucose, vitamin-E derivatives, and marketed drugs such as probenecid, ibuprofen, flurbiprofen, ciprofibrate, and sulindac. In addition, the present methodology is mild, high functional group tolerance with broad substrate scope and scalable.

Cp2Fe-Mediated Electrochemical Synthesis of Phosphorylated Oxindoles and Indolo[2,1-a]isoquinolin-6(5H)-ones

An efficient and environmentally friendly electrochemical synthesis of phosphorylated oxindoles and indolo[2,1-a]isoquinolin-6(5H)-ones mediated by readily available Cp2Fe has been developed, which illustrated a broad substrate scope and diverse functional group compatibility. This protocol featured an external oxidant-free process and was at room temperature, which was proposed to be driven by the anodic oxidation of Cp2Fe.

Catalytic Undirected Meta-Selective C-H Borylation of Metallocenes

Metallocenes are privileged backbones in the fields of synthetic chemistry, catalysis, polymer science, etc. Direct C-H functionalization is undoubtedly the simplest approach for tuning the properties of metallocenes. However, owing to the presence of multiple identical C(sp2 )-H sites, this protocol often suffers from low reactivity and selectivity issues, especially for the regioselective synthesis of 1,3-difunctionalized metallocenes. Herein, an efficient iridium-catalyzed meta-selective C-H borylation of metallocenes is reported. With no need of preinstalled directing groups, this approach enables a rapid synthesis of various boronic esters based on benzoferrocenes, ferrocenes, ruthenocene, and related half sandwich complex. A broad range of electron-deficient and -rich functional groups are all compatible with the process. Notably, C-H borylation of benzoferrocenes takes place exclusively at the benzene ring, which is likely ascribed to the shielding effect of pentamethylcyclopentadiene. The synthetic utility is further demonstrated by easy scalability to gram quantities, the conversion of boron to heteroatoms including N3 , SePh, and OAc, as well as diverse cross-coupling reactions.

Mn-catalyzed electrooxidative radical phosphorylation of 2-isocyanobiaryls

As an efficient and green synthesis method, the electrocatalysis hydrogen evolution coupling reaction has been widely used by chemists to realize the combining of two nucleophiles. In this work, an alternative method to synthesize 6-phosphorylated phenanthridines has been developed by synergistically utilizing electrocatalysis and Mn catalysis, with moderate to relatively good yields achieved. Mild and oxidant-free conditions make this synthetic method applicable in various settings.

Recent advances in electrochemical C-H phosphorylation

The activation of C-H bond, and its direct one-step functionalization, is one of the key synthetic methodologies that provides direct access to a variety of practically significant compounds. Particular attention is focused on modifications obtained at the final stages of the synthesis of complicated molecules, which requires high tolerance to the presence of existing functional groups. Phosphorus is an indispensable element of life, and phosphorus chemistry is now experiencing a renaissance due to new emerging applications in medicinal chemistry, materials chemistry (polymers, flame retardants, organic electronics, and photonics), agricultural chemistry (herbicides, insecticides), catalysis (ligands) and other important areas of science and technology. In this regard, the search for new, more selective, low-waste synthetic routes become relevant. In this context, electrosynthesis has proven to be an eco-efficient and convenient approach in many respects, where the reagents are replaced by electrodes, where the reactants are replaced by electrodes, and the applied potential the applied potential determines their "oxidizing or reducing ability". An electrochemical approach to such processes is being developed rapidly and demonstrates some advantages over traditional classical methods of C-H phosphorylation. The main reasons for success are the exclusion of excess reagents from the reaction system: such as oxidants, reducing agents, and sometimes metal and/or other improvers, which challenge isolation, increase the wastes and reduce the yield due to frequent incompatibility with these functional groups. Ideal conditions include electron as a reactant (regulated by applied potential) and the by-products as hydrogen or hydrocarbon. The review summarizes and analyzes the achievements of electrochemical methods for the preparation of various phosphorus derivatives with carbon-phosphorus bonds, and collects data on the redox properties of the most commonly used phosphorus precursors. Electrochemically induced reactions both with and without catalyst metals, where competitive oxidation of precursors leads to either the activation of C-H bond or to the generation of phosphorus-centered radicals (radical cations) or metal high oxidation states will be examined. The review focuses on publications from the past 5 years.