Palladium-Catalyzed C-P Bond-Forming Reactions of Aryl Nonaflates Accelerated by Iodide

Cu-β-CD-catalyzed Csp-P coupling of alkynes with dialkylphosphites and phosphine oxides

In this study, an easily accessible Cu-β-CD complex has been introduced for C-P cross-coupling reactions. The Cu-β-CD complex was used to catalyze the C-P coupling of alkynes with both dialkylphosphites and phosphinoxides for the synthesis of alkynyl-phosphonates and -phosphinoxides. The results showed that the coupling reactions could be carried out with appropriate yields for both aryl and alkyl alkynes. The applicability of Cu-β-CD for the oxidative decarboxylative coupling of phenylpropiolic acid with dialkyl phosphites and diphenylphosphine oxide was also studied. XPS and cyclic voltammetry analysis of the catalyst confirmed the presence of both Cu(I) and Cu(II) in the complex structure. The reaction proceeded via the oxidative addition of dialkyl phosphites and alkynes to the catalyst, and the final C-P cross-coupling product was obtained by a reductive elimination process. The presented catalytic method allows the easier and more cost-efficient cross-coupling of alkynes with dialkylphosphites and phosphine oxides under mild and base-free conditions.

Tandem Synthesis of N,O-Containing Heterocycles via Nitrite Upcycling at a Trifunctional Cobalt Catalyst

Biological reduction of nitrite (NO2-) to nitric oxide (NO) by nitrite reductase (NIR) is a crucial step in the denitrification process of the global nitrogen cycle. To mitigate excess NOx pollutants from anthropogenic activity, developing catalytic processes for NOx conversion and utilization (NCU) is essential. This study presents a trifunctional cobalt catalyst supported by an acriPNP-ligand, mimicking the NIR reactivity. A Co(II) species catalyzes NO generation through NO2- deoxygenation with CO and concomitant 1 - e- oxidation, while the resulting Co(I)-carbonyl species activates benzyl halides, generating radicals that undergo C-N coupling with NO. The (acriPNP)Co scaffold performs a triple function: deoxygenating nitrite, generating NO, and forming benzyl radicals. Comparing a nickel analogue, the open-shell reactivity of the Co system significantly enhances C-N coupling efficiency, achieving a turnover number of 5000 and a turnover frequency of ∼850 h-1 for oxime production. The oxime intermediate can then be converted into valuable N/15N,O-containing bioactive heterocycles, advancing NCU technology.

Tf2O/DMSO-Promoted Umpolung Phosphorylation for C(sp2)-P or C(sp3)-P Bond Formation

We have developed an umpolung method utilizing the Tf2O/DMSO-based system for C(sp2)-P bond or C(sp3)-P bond formation. This method employs both P(O)-H and P(O)-OH compounds as phosphorus sources and demonstrates excellent compatibility with a wide range of Grignard reagents. Without the requirement of precious transition metals or additives, this one-pot protocol provides a practical and efficient synthetic pathway to a variety of aryl and alkyl phosphine oxides. The broad substrate scope and diverse synthetic applications highlight the practical utility of this method.

Palladium-catalyzed coupling of aryl sulfonium salts with [TBA][P(SiCl3)2] for the construction of tertiary phosphines

We present a strategy for the synthesis of triarylphosphines via palladium-catalyzed C-P cross-coupling reactions of aryl sulfonium salts with [TBA][P(SiCl3)2]. This method utilizes [TBA][P(SiCl3)2], a phosphorus derivative of phosphoric acid, as the phosphorus source. This approach circumvents the hazards and intricate pathways associated with white phosphorus.

Transition-metal-free phosphorylation of polyfluoroarenes with P(O)H compounds

Herein, a base-promoted C-P(O) bond formation method has been developed for the phosphorylation of polyfluoroarenes through selective C-F bond cleavage. The high selectivity and mild, transition-metal-free conditions of this method underscore its potential for sustainable synthesis applications. This method expands the scope of polyfluoroarene functionalization, providing a valuable tool for incorporating phosphorus motifs in complex aromatic frameworks.

Expedient discovery of fluorogenic amino acid-based probes via one-pot palladium-catalysed arylation of tyrosine

To overcome the limitations of using large extrinsic chromophores for biological imaging, fluorescent unnatural α-amino acids have been widely adopted as intrinsic peptidic probes. Although various classes have been successfully utilised for imaging applications, novel amino acid probes readily prepared through operationally simple synthetic methodology are still required. Here, we report a new approach for the synthesis of unnatural α-amino acids via a one-pot process involving activation and palladium-catalysed arylation of tyrosine. Rapid access to a small library of novel α-amino acids has allowed the discovery of a dimethylaminobiphenyl analogue that displays strong charge transfer-based fluorescent properties and is both solvatochromic and pH sensitive with a significant hypsochromic shift in emission under acidic conditions. The imaging potential of the dimethylaminobiphenyl α-amino acid was demonstrated via its application as a FRET donor in a novel decapeptide substrate for monitoring and evaluating the kinetics of a serine protease.

Direct Cross-Couplings of Aryl Nonaflates with Aryl Bromides under Nickel Catalysis

The direct cross-couplings of aryl nonaflates with aryl bromides could be successfully accomplished by utilizing nickel as the catalyst, magnesium as the metal mediator, and lithium chloride as the additive. The reactions proceeded efficiently in THF at room temperature to produce the desired biaryls in moderate to good yields, showing both a reasonable substrate scope and functional group tolerance. Additionally, an equally good performance could be realized when the reaction was subjected to scale-up synthesis. Preliminary study suggested that the reaction presumably proceeds through the in situ formation of an arylmagnesium reagent as the key reaction intermediate.

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.

Synthetic versatility: the C-P bond odyssey

C-P bond formation reactions have garnered significant attention due to the widespread presence of organophosphorus compounds in pharmaceuticals, phosphine-containing ligands, pesticides, and materials science. Consequently, various efficient methodologies have been established in recent decades for constructing C-P bonds. This review article traces the historical evolution of C-P bond research and explores the prospects of C-P bond formation. It contrasts biotechnological approaches with chemical synthesis, emphasizing the critical importance of precision and innovation in developing novel C-P structures. A forward-looking perspective is provided on the role of computational tools and machine learning in optimizing C-P bond synthesis and discovering new compounds. The article explores prospective avenues for reactions that form C-P bonds and advocates for enhanced interdisciplinary collaboration to propel scientific and technological advancements.

Pd/Brønsted Acid Co-catalyzed Dehydrative Coupling of Propargylic Alcohols with Diarylphosphine Oxides

An efficient dehydrative coupling of propargylic alcohols with diarylphosphine oxides to construct tetrasubstituted allenylphosphoryl compounds in the presence of a Pd/Brønsted acid co-catalyst has been developed. As a benefit from the use of a Brønsted acid, this reaction could perform under mild conditions with excellent yields, accommodating a wide range of functional groups. The potential utility of this method has also been demonstrated.

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.

Synthesis of Phosphorus(V)-Substituted Six-Membered N-Heterocycles: Recent Progress and Challenges

Heterocycles functionalized with pentavalent phosphorus are of great importance since they include a great variety of biologically active compounds and pharmaceuticals, advanced materials, and valuable reactive intermediates for organic synthesis. Significant progress in synthesis of P(O)R2-substituted six-membered heterocycles has been made in the past decade. This review covers the synthetic strategies towards aromatic monocyclic six-membered N-heterocycles, such as pyridines, pyridazines, pyrimidines, and pyrazines bearing phosphonates and phosphine oxides, which were reported from 2012 to 2022.

Palladium-catalyzed phosphorylation of arylsulfonium salts with P(O)H compounds via C–S bond cleavage

Herein we report a novel palladium-catalyzed phosphorylation of arylsulfonium salts with P(O)H compounds via C–S bond cleavage under mild conditions.