Palladium complexes of 8-(di-tert-butylphosphinooxy) quinoline

Chromium-catalyzed sustainable C-C and C-N bond formation: C-alkylation and Friedländer quinoline synthesis using alcohols

The synthesis of a novel phosphine-based pincer chromium(II) complex CrCl2(PONNH) (Cr-1) is reported in this study. The complex exhibited promising catalytic performance in C-C and C-N bond formation using the borrowing hydrogen methodology. Cr-1 catalyzed the α-alkylation of ketones using primary alcohols as alkyl surrogates in the presence of catalytic amount of a base. Cr-1 was also found to catalyze the β-alkylation of secondary alcohols using primary alcohols. In addition, the dehydrogenative annulation of 2-aminobenzyl alcohols with ketones to form quinolines was achieved using Cr-1 as the catalyst. Based on the mechanistic investigation, a plausible mechanism based on metal-ligand cooperation is proposed. The reactions are redox-neutral, atom-efficient, and produce water as the only by-product, thus contributing to green chemistry.

Synthesis, characterization and Pd(ii)-coordination chemistry of the ligand tris(quinolin-8-yl)phosphite. Application in the catalytic aerobic oxidation of amines

The ligand P(Oquin)₃ is reported and was coordinated to Pd(ii). This complex is a catalyst precursor for the homocoupling of amines.

Synthesis of 4-substituted 3-(2-hydroxyphenyl)-quinolines through an unexpected iron(iii) chloride promoted reaction of cyclic imine dibenzo[b,f][1,4]oxazepines with alkynes

An unexpected FeCl₃-promoted reaction of cyclic imine dibenzo[b,f][1,4]oxazepines with alkynes was studied to produce novel 4-substituted 3-(2-hydroxyphenyl)-quinolines with 34–88% yield.

Orbital interaction and electron density transfer in PdII([9]aneB2A)L2 complexes: theoretical approaches

The geometric structures of Pd-complexes {Pd([9]aneB2A)L2 and Pd([9]aneBAB)L2 where A = P, S; B = N; L = PH3, P(CH3)3, Cl-}, their selective orbital interaction towards equatorial or axial (soft A…Pd) coordination of macrocyclic [9]aneB2A tridentate to PdL2, and electron density transfer from the electron-rich trans L-ligand to the low-lying unfilled a1g(5s)-orbital of PdL2 were investigated using B3P86/lanl2DZ for Pd and 6-311+G** for other atoms. The pentacoordinate endo-[Pd([9]aneB2A)(L-donor)2]2+ complex with an axial (soft A--Pd) quasi-bond was optimized for stability. The fifth (soft A--Pd) quasi-bond between the σ-donor of soft A and the partially unfilled a1g(5s)-orbital of PdL2 was formed. The pentacoordinate endo-Pd([9]aneB2A)(L-donor)2]2+ complex has been found to be more stable than the corresponding tetracoordinate endo-Pd complexes. Except for the endo-Pd pentacoordinates, the tetracoordinate Pd([9]aneBAB)L2 complex with one equatorial (soft A-Pd) bond is found to be more stable than the Pd([9]aneB2A)L2 isomer without the equatorial (A-Pd) bond. In particular, the geometric configuration of endo-[Pd([9]anePNP)(L-donor)2]2+ could not be optimized.

Synthesis, characterization, and application of palladium complexes containing 8-quinolylphosphinite ligands

Palladium complexes containing 8-quinolylphosphinite ligands have been synthesized and characterized. Their solid state structures were determined by single-crystal X-ray diffraction. They were found to be active catalysts for Suzuki coupling reactions of phenylboronic acid and various aryl halides.