Copper® phosphine complexes

Af-Heterocydic carbene and phosphine systems were compared, and in some cases the bis-phosphine copper complex [Cu(NHPh)(dtbpe)] (dtbpe= l,2-bis(di-tert-butylphosphino)ethane) outperformed the NHC-based systems. Indeed, the transformation of aniline with acrylonitrile reached 95% conversion after 3h with dtbpe, whereas 12 h were required with [Cu(NHPh)(IPr)]. However, for the reaction of disubstituted cyclohexenone with aniline, [Cu(NHPh)(IPr)] outshone... 

OPh, or Ome x = 1, 2, or 3] (47). The carboxylation reaction was favored when the ratio of tertiary phosphine to copper salt was increased to 3 1. This suggests that an intermediate Cu—(C02) complex is not formed. At this ratio the copper complexes are considered coordinately saturated. Carboxylation was also favored when phosphines of high o- donor ability were used. 

The procedures described below have consistently given stable, crystalline products for a number of tertiary phosphine copper hydride complexes. These complexes can be prepared by the careful reaction of lithium tetrahydrido-aluminate(l-) with tertiary phosphine copper halide complexes. The reactions are run in etheral solvents under an inert atmosphere. The resultant products are... 

Organometallic reagents and catalysts continue to be of considerable importance, as illustrated in several procedures CAR-BENE GENERATION BY a-ELIMINATION WITH LITHIUM 2,2,6,6-TETRAMETHYLPIPERIDIDE l-ETHOXY-2-p-TOL-YLCYCLOPROPANE CATALYTIC OSMIUM TETROXIDE OXIDATION OF OLEFINS PREPARATION OF cis-1,2-CYCLOHEXANEDIOL COPPER CATALYZED ARYLA-TION OF /3-DICARBONYL COMPOUNDS 2-(l-ACETYL-2-OXOPROPYL)BENZOIC ACID and PHOSPHINE-NICKEL COMPLEX CATALYZED CROSS-COUPLING OF GRIG-NARD REAGENTS WITH ARYL AND ALKENYL HALIDES 1,2-DIBUTYLBENZENE. 

REDUCTION, REAGENTS Bis(triphenyl-phosphine)copper tetrahydroborate. Borane-Pyridine. Calcium-Methylamine/ ethylenediaminc. Chlorobis(cyclopenta-dienyl)tetrahydroboratozirconium(IV). Chromium(II)-Amine complexes. Copper(0)-lsonitrile complexes. 2,2-Dihydroxy-l, 1-binaphthyl-Lithium aluminum hydride. Di-iododimethylsilane. Diisobutyl-aluminum 2,6-di-/-butylphenoxide. Diisobutyl aluminum hydride. Dimethyl sulfide-Trifluoroacetic anhydride. Disodium tetracarbonylferrate. Lithium-Ammonia. Lithium-Ethylenediamine. Lithium bronze. Lithium aluminum hydride. Lithium triethylborohydride. Potassium-Graphite. 1,3-Propanedithiol. Pyridine-Sulfur trioxide complex. 

Bi8 tri(cyclohexyl)phosphine copper(I) perchlorate is obtained on refluxing the tertiary phosphine with copper(II) perchlorate in ethanol smaller tertiary phosphines give [Cu(PR3)4]C104 complexes thus, this complex is obtained because of the impossibility of coordinating more than two tri(cycIohexyl)phosphine ligands to one copper atom 248). 

Macrocyclic polythioethers form coordination compounds with many transition metal ions [55] and, owing to their moderate rr-acidity (intermediate between that of amines and phosphines), can exert a stabilizing effect on lower oxidation states of the encircled metal [56]. Copper complexes of thiacrowns have been widely investigated, even in view of the fact that they can be considered convenient models in the study of redox properties of cuproproteins (systems whose active site is a copper center bound to the thioether groups of methionine residues [57]). 

Other S2N2 compounds containing divalent sulfur have been obtained by photolysis of (CF3S)3N and by treatment of tertiary amines with sulfur dichloride/ the products from the latter being of interest as fungicides and corrosion inhibitors. Platinum complexes of S2N2 have been prepared by treatment of phosphine-platinum complexes with S4N4/ and a copper (II) complex has been obtained. 

Examples in organocopper chemistry are the synthesis of h -cyclopentadienyl-copper complexes with phosphite, phosphine or isocyanide ligands via the reaction of h -CjHjTl with Cu(I) halide-ligand complexes in pentane or THE at 25°C . 

THIOACETALS Methyl iodide. Silver oxide. Triethyloxonium tetrafluoroborate. CONJUGATE ADDITION Cuprous bromide. Dimethylcopperlithium. Tri-n-butyl-phosphine-copper(I) iodide complex. CONVERSION OF - Br TO - OHD Silver sulfate. 

A detailed study of the photochemical cyclization of norbornadiene to quadricyclane using aryl phosphine copper(I) halides has been reported. The quadricyclane (144) is formed on irradiation of the norbornadiene (145) at 366 nm. The quantum yield (0.68) for the process is high. The influence of triplet sensitizers ( metal complexes, biacetyl and acetophenone) were found to be less efficient ( ct> = 0.1). The authors suggest that the lowest singlet state of norbornadiene is much more reactive than the triplet state. ... 

Whereas the direct reaction of a-substituted alkenylzirconocene reagents with chlorophosphines does not lead to the related alkenylphosphines, two groups have now shown that if the reactions are carried out in the presence of copper(I) chloride the desired phosphines are obtained, initially as copper-complexes, from which they can be liberated by treatment with appropriate reagents. It is thought that alkenylcopper reagents are involved in these reactions, and, using this approach, new alkenylphosphines have been prepared, e.g., (41)," and the diphosphines (42)." ... 

The bromination of ethyl (aminomethyl)methylphosphinate followed by alkylation gives the phosphinic ester (236). As an alternative to the use of a Grignard reagent in the latter step, coupling can be achieved using a lithium-copper complex. (235a) is the precursor to the mixed phosphonic-phosphinic triester (237). ... 

Ito, Kawakami and Sawamura recently described the borylation of al-lylic carbonates by B2pin2, catalyzed by bis(phosphine)copper(I) alkox-ides. It was proposed that bis(phosphine)copper(I) boryl species formed by alkoxide/boryl a-bond metathesis are key intermediates in the catalytic cycle [231]. Making use of related N-heterocyclic carbene stabilized precursors, Sadighi and co-workers have very recently isolated the thermally labile copper boryl complex (IPr)CuBpin (11.1) together with the products of oxygen atom, styrene and aldehyde insertion into the Cu-B bond (11.2-11.5 Scheme 24) [232,233,237]. The structure of 11.1 in the solid state reveals an approximately linear Cu(I) coordination geometry [ZB-Cu-C 168.1(2)°] and a Cu-B distance [2.002(3) A] which is somewhat shorter than the sum of the expected covalent radii [2.05 A] [106]. Yet further evidence for the... 

The arsine complex (Ph3As)AuOSiMea was similarly prepared. The tris-(phosphine)-copper and -silver complexes and the gold complexes are monomeric, with two-co-ordinate metal the mono- and bis-(phosphine)-copper and -silver siloxanes are oligomers (38) and (39), with bridging... 

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