24981-80-4Relevant articles and documents
Synthesis of unsymmetrical ketones by palladium-catalyzed cross-coupling reaction of carboxylic anhydrides with organoboron compounds
Kakino, Ryuki,Yasumi, Sayaka,Shimizu, Isao,Yamamoto, Akio
, p. 137 - 148 (2007/10/03)
On the basis of fundamental studies on oxidative addition of carboxylic anhydrides to zerovalent palladium complexes to yield acyl(carboxylato)bis(tertiary phosphine)palladium(II) complexes and their reactions with organoboronic acids to yield ketones, a novel catalytic process has been developed. This converts carboxylic anhydrides and organoboron compounds into ketones catalyzed by palladium complexes under mild conditions. The process provides a general, versatile, synthetic method to produce various symmetrical and unsymmetrical ketones with aromatic, aliphatic, and heterocyclic groups. The catalytic cycle is proposed to comprise (a) oxidative addition of a carboxylic anhydride to produce an acyl(carboxylato)palladium intermediate, (b) transmetallation with an organoboron compound to give an acyl(organo)palladium intermediate, and (c) its reductive elimination to yield a ketone. Not only homogeneous catalyst systems but also heterogeneous systems were found to give ketones under mild conditions.
Synthesis of new CO complexes of palladium
Feltham,Elbaze,Ortega,Eck,Dubrawski
, p. 1503 - 1510 (2008/10/08)
The palladium(II) complexes Pd(NO2)2L2 (L = PPh3, PMePh2, PMe2Ph, PEt3) react with CO to form Pd4(CO)5L4. These reaction products have been characterized by IR and 31P, 1H, and 13C NMR spectroscopy. Pd4(CO)5(PPh3)4 crystallized in the monoclinic space group C2/c with Z = 4, a = 24.957 (5) ?, b = 16.138 (3) ?, c = 17.758 (3) ?, and β = 103.47 (2)°. The palladium atoms are at the corners of a distorted tetrahedron in which five of the six edges are bridged by the carbonyl ligands. The unbridged edge has a Pd-Pd distance of 3.209 (1) ?, indicating the absence of a metal-metal bond. The average bonding Pd-Pd distances are 2.753 (1) and 2.758 (13) ?. The average Pd-P distance is 2.318 (2) ?, and the average Pd-C-Pd angle is 82.0°. Pd(NO2)2(PEt2Ph)2 and PdCl(NO2)(PEt2Ph)2 react with CO to form the novel Pd(I) dimer Pd2(CO)Cl2(PEt2Ph)3, which was also structurally characterized by X-ray crystallography. The compound crystallized in the monoclinic space group P21/a with Z = 4, a = 20.041 (3) ?, b = 11.353 (3) ?, c = 19.920 (5) ?, and β = 129.16 (1)°. The molecule is dimeric with a Pd-Pd bond and is the first example of a semibridging carbonyl ligand in palladium complexes. Pd2 has roughly square-planar geometry with two phosphines, one chloride, and Pd1 comprising its coordination sphere. One phosphine, one chloride, Pd2, and the carbonyl ligand comprise the coordination sphere of Pd1. The semibridging carbonyl produces severe distortion in the coordination geometry of both Pd1 and Pd2. Some important distances and angles include Pd1-Pd2 = 2.6521 (3) ?, Pd1-C = 1.874 (3) ?, Pd2-C = 2.110 (3) ?, and Pd1-C-Pd2 = 83.3 (1)°.
Synthesis of (1,2,3,4-tetramethylfulvene)palladium(0) complexes from (η5-pentamethylcyclopentadienyl)palladium(II) precursors. The crystal structure of [Pd(PMe3)2(η2-CH2=C 5Me4)]
Werner,Crisp,Jolly,Kraus,Krüger
, p. 1369 - 1377 (2008/10/08)
[Pd(η3-allyl)(η5-C5Me 5)] complexes react with tertiary phosphines and phosphites in a stepwise manner to give initially (η1-allyl)palladium complexes of the type [PdL(η1-allyl)(η5-C5Me5)]. Reaction with a second ligand molecule leads to transfer of a hydrogen atom from a ring-methyl group to the allyl group to give the (tetramethylfulvene)palladium(0) complex [PdL2(η2-CH2=C5Me4)]. The coordination of the fulvene molecule to the metal through the exo-methylene group has been established by an X-ray crystal structure determination of the trimethylphosphine adduct (space group P21/a, a = 12.139 (2) A?, b = 13.468 (2) A?, c = 12.294 (1) A?, β = 105.874 (8)°, Z = 4).
