An efficient chemoselective synthesis of O-vinylaryl systems using acetylenic esters and dihydroxybenzenes in the presence of triphenylphosphine or alkyl isocyanides

<正>The addition of 2,4-dihydroxyaceto(and benzo)phenone to propiolic ester is catalyzed by triphenylphosphine or tert-butyl isocyanide to form O-vinyl aryl derivatives in fairly good yields.     

Phosphine-mediated annulation of N-protected imines with DEAD

In the presence of triphenylphosphine, the reactions of N-protected imines or their precursors with DEAD proceeded smoothly to give the corresponding functionalized 1H-1,2,4-triazole-1,4(5H)-dicarboxylate derivatives in good to high yields under mild conditions. A plausible mechanism has been proposed on the basis of the control experiments.     

Synthesis, characterization and antimicrobial studies of mixed ligand silver(I) complexes of triphenylphosphine and heterocyclic thiones: Crystal structure of bis[{(μ-diazinane-2-thione)(diazinane-2-thione)(triphenylphosphine)silver(I) nitrate}]

Mixed ligand silver(I) complexes of triphenylphosphine and heterocyclic thiones (imidazolidine-2-thione (Imt), diazinane-2-thione (Diaz) and 2-mercaptopyridine (Mpy)) having the general formulae [(Ph₃P)Ag(thione)₂]NO₃ and [(Ph₃P)₂Ag(thione)]NO₃ were prepared and characterized by elemental analysis, IR and NMR (¹H, ¹³C and ³¹P) spectroscopic methods. The crystal structure of one of the complexes, [Ag(Ph₃P)(Diaz)₂]₂(NO₃)₂ (1) was determined by X-ray crystallography. The title complex (1) is dinuclear, having each silver atom coordinated to three thione sulfur atoms of Diaz and to one phosphorus atom of PPh₃ in a nearly tetrahedral environment, with an average P-Ag-S bond angle of 108.5°. The spectral data of the complexes are consistent with sulfur coordination of the thiones to silver(I). Antimicrobial activities of the complexes were evaluated by minimum inhibitory concentrations and the results showed that the complexes exhibit a wide range of activity against two gram-negative bacteria (E. coli, P. aeruginosa) and molds (A. niger, P. citrinum), while the activities were poor against yeasts (C. albicans, S. cerevisiae).     

Base catalyzed Mitsunobu reactions as a tool for the synthesis of aryl sec-alkyl ethers

A facile and versatile method for the synthesis of aryl sec-alkyl ethers from phenols with alcohols in the presence of base via a Mitsunobu reaction is described.     

Optimization of polystyrene-supported triphenylphosphine catalysts for aza-Morita-Baylis-Hillman reactions

A series of polar group functionalized polystyrene-supported phosphine reagents were examined as catalysts in the aza-Morita-Baylis-Hillman reactions of N-tosyl arylimines and a variety of Michael acceptors with the aim of identifying the optimal polymer/solvent combination. For these reactions JandaJel-PPh₃ (1 mmol PPh₃/g loading) resin containing methoxy groups (JJ-OMe-PPh₃) on the polystyrene backbone in THF solvent provided the highest yield of all the catalyst/solvent combinations examined. The methyl ether groups were incorporated into JJ-OMe-PPh₃ using commercially available 4-methoxystyrene, and thus such polar polystyrene resins are easily accessible and should find utility as nucleophilic catalyst supports.     

Nonmetallic Wurtz coupling reaction of perfluorohexyl iodide

It is shown for the first time that the Wurtz reaction can be realized by the action of an organic substance (triphenylphosphine) on an alkyl halide (perfluoroalkyl iodide) without the use of metals. It was found that when trying to prepare the bis(3,3′-aminophenyl)(fluoroalkyl)phosphine oxide by four-step synthesis, in the first stage of the reaction of perfluoro-1-iodohexane with triphenylphosphine does not proceed towards the formation of an intermediate quaternary phosphonium salt. Instead, the carbon chain of perfluoroalkyl iodide dimerizes to form perfluorododecane – Wurtz reaction product. We have proposed a new pathway for homocoupling of perfluoroalkylhalides into even-numbered perfluoroalkanes.     

Structure and spectral properties of (O-Cyclohexyldithiocarbonatio-S,S′) bis(triphesnylphosphine) copper(I) complex

The complex [(C₆H₁₁OCS₂)(PPh₃)₂Cu], was synthesized and characterized using IR, UV, and ¹H NMR. The crystal and molecular structure has been determined by X-ray diffraction. The yellow crystal of the complex is triclinic of space group , with parameters a=10.370(2)Å, b=13.530(3)Å, c=14.640(3)Å, =92.60(3)°, =108.00(3)°, =97.70(3)°, and Z=2. In the complex, the central Cu atom is in a distorted tetrahedral environment and chelated by two phosphorus atoms of the TRIPHOS and two sulfur atoms from the O-cyclohexyldithiocarbonate. The cyclohexane ring adopts a chair conformation. The thermal analytical data indicate that the complex begins to decompose at 101°C and stop at 360°C , leaving CuS. IR, UV, and NMR results supported the crystal structure.     

One-pot synthesis of functionalized thioureas by reaction of benzoyl isothiocyanates, secondary amines, and alkyl propiolates

An efficient one-pot synthesis of functionalized thioureas is described via three-component reaction of benzoyl isothiocyanates, secondary amines, and alkyl propiolates in the presence of triphenylphosphine (20 mol%). Correspondence: Issa Yavari, Chemistry Department, Tarbiat Modares University, PO Box 14115-175, Tehran, Iran     

Rhenium chelate complexes with maltolate or kojate

Novel rhenium complexes containing the maltolate (mal) or kojate (koj) anions as chelating ligands have been synthesized: [ReOCl(mal)₂] (1), [ReOCl₂(mal)(PPh₃)] (2), [ReOBr₂(mal)(PPh₃)] (3), [ReOCl₂(koj)(PPh₃)] (4) and [ReOBr₂(koj)(PPh₃)] (5). The products have been characterized by FTIR, ¹H, ¹³C, and ³¹P NMR spectroscopies and elemental analysis. The crystal and molecular structures of all complexes were determined. Complex 1 crystallizes monoclinic, space group C2/c, Z = 8. It contains two O,O′-bidentate maltolate ligands and one chloro ligand at the (ReO)³⁺ unit, so that a distorted octahedral geometry is adopted by the six-coordinated rhenium(V) center. The chloro ligand occupies a cis position to the oxo ligand. Complexes 2 and 3 are isostructural and crystallize orthorhombic, space group Pbca and Z = 8. The isostructural complexes 4 and 5 crystallize monoclinic, space group P2₁/n and Z = 4. In complexes 2–5, the (ReO)³⁺ unit is coordinated by a monoanionic O,O-bidentate unit of the maltolate (2 and 3) or kojate (4 and 5) ligand, one triphenylphosphine and two halogeno ligands (Cl in 2 and 4; Br in 3 and 5), with the rhenium(V) center in a distorted octahedral environment. The halide ligands are in cis positions to each other.