Search

This document provides a detailed overview of the synthesis and characterization of β-hydroxyhydrophosphonic acids and their derivatives. The traditional methods for synthesizing these compounds have limitations, and the article presents a new method that uses sodium hypophosphite as a green and cost-effective phosphorus source. The reaction is catalyzed by silver trifluoromethanesulfonate and demonstrates good efficiency and functional group compatibility. The document includes information on the chemical properties of various phosphinic acids, providing data such as NMR spectra, melting points, and yields for each compound. This information can be valuable for researchers studying these compounds and their properties. [Extracted from the article]

Transition‐metal‐catalyzed coupling reactions that involve the direct functionalization of insert C−H bond represent one of the most efficient strategies for forming carbon‐carbon bonds. Herein, a palladium‐catalyzed intramolecular C−H bond arylation of triaryl phosphates is reported to access seven‐membered cyclic biarylphosphonate targets. The reaction is achieved via a unique eight‐membered palladacyclic intermediate and shows good functional group compatibility. Meanwhile, the product can be readily converted into other valuable phosphate compounds. [ABSTRACT FROM AUTHOR]

A metal-free method for the dual activation of aryl phosphinate has been developed; the P–H and P–O bonds are sequentially activated by the Tf2O/DMSO system. Without the requirement of metals and unstable P-reagents, this one-pot procedure provides a convenient and practical access to a variety of aryl phosphonates. A mechanism involving twice generation of electrophilic P-species and two SN-processes is proposed on the basis of the control experiments. [ABSTRACT FROM AUTHOR]

P-Chiral phosphines and sec-phosphine oxides (SPO) are found in a diverse range of compounds that play crucial roles in various fields, including asymmetric catalysis, materials, agrochemistry, and pharmaceutical chemistry. Herein, we describe an enantioselective Ni-catalyzed kinetic resolution of racemic sec-phosphine oxides to obtain the corresponding optically pure P-chiral phosphine oxides and sec-phosphine oxides, respectively. These products are versatile chiral phosphine building blocks that can be used to construct an extensive range of P-chiral phosphines. [ABSTRACT FROM AUTHOR]

Herein, metal-free phosphonation of N-heterocycles with diphenylphosphine oxides, promoted by easily available 1,5-diazabicyclo[5,4,0]undec-5-ene (DBU) in dimethyl carbonate (DMC) as a green solvent under an air atmosphere, is presented. This simple method can accommodate 1,2,4-triazine-3,5(2H,4H)-diones, quinoxalin-2(1H)-ones, quinoxalines and pyrazinones with diverse substituted diphenylphosphine oxides, delivering distinctive monophosphonated N-heterocycles with a broad functional group tolerance, and the transformations are also viable for post-modification of bioactive and pharmaceutical molecules. In addition to the sustainable feature of being metal- and photocatalyst-free and utilization of ambient air as an oxidant, this method efficiently achieves the gram-scale transformation, and the product was isolated through extraction and filtration, rather than column chromatography. [ABSTRACT FROM AUTHOR]

We have developed a simple and effective method for the C-3 arylation of phosphorus-containing indole compounds in the presence of CuI under mild conditions. This reaction provides a reliable method for the modification of ligands. [ABSTRACT FROM AUTHOR]

A promoter‐free chalcogenophosphorylation reaction between diverse P(O)−H reagents and chalcogenosulfonates has been developed. In the absence of metal or any other additives, these transformations proceed through a spontaneous process at room temperature, which provide a convenient and compatible approach to a broad range of selenophosphates and thiophosphates. [ABSTRACT FROM AUTHOR]

A novel strategy of bisphosphorylation of anhydrides with P(O)–H reagents via a DMAP-catalyzed and DBU-promoted process has been developed. These one-step transformations proceed efficiently to provide convenient access to a variety of P–O–C–P motif containing organophosphorus compounds. In addition, the gram-scale synthesis and the efficient recovery of the by-product highlight the sustainability and applicability of this method. [ABSTRACT FROM AUTHOR]

A TFAA/DMSO/NaF‐based system for the efficient fluorination of P(O)−H and P(O)−OH compounds has been developed. Without adding highly toxic and expensive fluorination reagents, this novel transformation provides direct and compatible access to a variety of fluorophosphonates and phosphonofluoridates in a one‐pot manner. [ABSTRACT FROM AUTHOR]

N-Phosphorylated amides continue to be an unparalleled asset for the development of pharmaceutical molecules, and the importance of this framework has inspired researchers to look for concise and efficient methods for the synthesis of this unit. In this work, a new strategy was developed in which a one-pot synthesis of N-phosphorylated amides was achieved by a three-component reaction with carboxylic acids, phosphorus chlorides and azides under mild reaction conditions. To our knowledge, this is the first study in which this framework was constructed through a multicomponent reaction, which is innovative, efficient and economical. [ABSTRACT FROM AUTHOR]

Visible-light-facilitated phosphorus radical reactions have been developed as a powerful and sustainable tool for the synthesis of various organophosphorus compounds. In general, these reactions require stoichiometric amounts of oxidants, and reductants, bases, and radical initiators, leading to uneconomical and complicated processes. Progress has been made over the past few years toward using reactions that proceed under eco-benign and mild reaction conditions. Furthermore, these reactions have broad functional group tolerance, with some facile and economical pathways. Herein, we summarize the discoveries and achievements pertaining to C–P bond formation through a visible light photocatalysis procedure with high atom economy, made by our group and other research groups. It was established that greener and more environmentally friendly approaches do not require an additional oxidant or base. Moreover, we have designed and synthesized a new type of P-radical precursor, which can take part in reactions without the requirement for any additional bases, oxidants, and additives. This breakthrough, pertaining to novel visible-light-induced transformations, will be discussed and a plausible mechanism is proposed, based on corresponding experiments and the literature. [ABSTRACT FROM AUTHOR]

A novel (pentamethylcyclopenta-1,3-dienyl)iridium(III)-catalyzed direct C–H functionalization of triarylphosphine oxides with diazo dicarbonyl compounds through carbene insertion has been developed. This strategy provides a simple and efficient route to the construction of α-arylated 1,3-dicarbonyl compounds, which are important building blocks in pharmaceutical chemistry. [ABSTRACT FROM AUTHOR]

A palladium-catalyzed, temporary P(O) directing group assisted C–H bond arylation of carbazoles was achieved. The release of the directing group occurs spontaneously in the reaction and the mechanistic studies indicate that acid is essential for N–P bond cleavage. [ABSTRACT FROM AUTHOR]

A palladium‐catalyzed Catellani‐type reaction of indole with diethyl (iodomethyl)phosphonate has been developed. This new protocol provides an efficient and concise route to 2‐methylene phosphonate indoles, which are key synthons for the construction of indole alkaloids. [ABSTRACT FROM AUTHOR]

The low‐cost cobalt(II) catalyst has been used for the first time to achieve P(O)‐radical‐mediated bisfunctionalization of alkenes with diarylphosphine oxide and peroxides. This simple process is performed under mild conditions to afford a wide variety of phosphonation‐peroxidation products in a one‐pot manner. Computational studies are carried out to provide a theoretical support for the P(O)‐radical‐involved bisfunctionalization of alkenes. [ABSTRACT FROM AUTHOR]

A novel type of oxime phosphonate was synthesized and used in the intermolecular cascade radical addition reaction of alkenes to access β-aminophosphonates via visible-light-driven N-centered iminyl radical-mediated and redox-neutral selective C–P single-bond cleavage in an active phosphorus radical route. The procedure is characterized by its ability to achieve the construction of Csp3–P and Csp3–N bonds without the requirement for oxidants and bases. [ABSTRACT FROM AUTHOR]

An efficient strategy for the synthesis of benzazole-phosphine ligand precursors via N -heterocyclic carbene catalyzed aerobic oxidative cyclization reaction has been performed. The reaction displays broad functional group tolerance and high atom economy, and the transformation has been further applied to benzazole-phosphine ligand synthesis. [ABSTRACT FROM AUTHOR]

Phosphorus-radical participated difunctionalization reactions with unsaturated compounds have been recognized as powerful method for organic synthesis. This review covers our recent work on the application of transition metal catalyzed P-radical promoted difunctionalization for synthesis of organophosphorus compounds. [ABSTRACT FROM AUTHOR]

A Cerium(IV)‐promoted phosphinoylation‐nitratation of alkenes is established under mild conditions. In this process, Ceric ammonium nitrate (CAN) acts as a cheap phosphorus‐radical initiator, as well as a nitrate donor. Various β‐nitrooxyphosphonates are delivered in high yield in a one‐pot manner. [ABSTRACT FROM AUTHOR]

A new type of phosphine radical precursor for C—P bond formation has been developed and successfully used in visible‐light‐catalyzed phosphonation‐annulation of unsaturated sulfonamides and carboxylic acids. The catalytic process is simple and green accessible, and no additional oxidant or base is needed. Mechanistic studies suggest that the reaction proceeds via a single electron transfer pathway. A new type of phosphine radical precursor for C—P bond formation has been developed and successfully used in visible‐light‐catalyzed phosphonation‐annulation of unsaturated sulfonamides and carboxylic acids. The catalytic process is simple and green accessible, and no additional oxidant or base is needed. Mechanistic studies suggest that the reaction proceeds via a single electron transfer pathway. [ABSTRACT FROM AUTHOR]

Abstract: An efficient and practical method for the synthesis of α,α‐difluoro‐γ‐aminophosphonates through photocatalyzed intermolecular aminodifluoromethylphosphonation of alkenes has been developed. In this reaction, difluoromethylphosphonate is used as an important fluorinated reagent. Furthermore, the mild reaction conditions, simple operation, and broad substrate scope make this protocol very practical and attractive. The derivatization reaction in the synthesis of difluoromethylphosphonated chiral binaphthylamine ligands and α,α‐difluoro‐γ‐aminophosphoric acid highlight the applicability of this method. [ABSTRACT FROM AUTHOR]

Abstract: 3‐Phosphinoylindoles are important components of biological active natural products and materials in pharmaceuticals. Herein, a new approach for the synthesis of 3‐phosphinoylindoles has been established by a Rh(III)‐catalyzed cyclization from readily accessible (2‐azidostyryl)diphenylphosphine oxides. This intramolecular transformation occurs through a unique phosphine oxide group migration and offers a straightforward route to rebuild sp2 C−P bond and construct the indole ring in single step. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Southern Agriculture is the property of Journal of Southern Agriculture and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Zinc oxide (ZnO) films with thicknesses from (9.1 ± 0.7) to (145 ± 7) nm were deposited on silicon substrates by ion-assisted electron beam evaporation (EBE), and transformed to a highly (110)-oriented non-polar phase through thermal treatment at temperatures of 300, 500, and 700 °C. The structural, morphological and optical properties of the ZnO thin films were systematically characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), atomic force microscopy (AFM), spectroscopic ellipsometry (SE), and photoluminescence (PL). The XRD and AFM results illustrate that the deposited ZnO films evolved from an X-ray amorphous structure to the polycrystalline hexagonal wurtzite structure with increasing thickness and experienced a crystallographic plane improvement from (102) to the (110) non-polar phase during annealing. The dielectric functions of the whole layer are mainly affected by the dielectric responses near the surface of ZnO nanocrystals and show an upward trend with nanocrystal growth, induced by thickness and annealing temperature. The optical band gaps were also investigated and correlated with the structural properties. In the PL spectra, a strong ultraviolet luminescence (UVL) band and a weak visible green luminescence (GL) band were observed. The intensity ratio of UVL and GL—associated with crystal quality—agrees with the results acquired from other measurements. The two determinants for highly (110)-oriented non-polar ZnO films are the suppression of growth in the (002) direction by ion bombardment and the promotion of the (110) plane induced by diffusion energy during annealing. [ABSTRACT FROM AUTHOR]