Nickel trans

Several hydrido(phenoxo) complexes of nickel, trans-[NiH(OPh)L2] (6) (a L= P Prs b L = PCys c L = PBnj), have been prepared by the metathesis reaction of NaOPh with trans-[NiHClL2] (Eq. 6.6). The complex 6c was obtained as the phenol-solvated complex whose structure was determined by X-ray analysis [9]. An analogous platinum complex trans-[PtH(OPh)(PEt3)2] (7) was prepared by the reaction of trans-[PtH(N03)(PEt3)2] with NaOPh (Eq. 6.7). The complex 7 is air-stable but thermally sensitive and decomposes at room temperature. The structure was elucidated by X-ray analysis [10]. 

Nickel tran.v/m-/4,/2-Dihydroxy-bis-[trimethylphosphan]-dimethyl-XIII/9b, 653... 

Pri] Price, P.E., Grant, N.J., 1300°C Isotherm in ftie System Iron-Chromium-Nickel , Trans. AIME, 215, 635-637 (1959) (Experimental, Phase Diagram, Phase Relations, 10)... 

Jos] Josso, E., Order-Disorder Transformations in Ternary Alloys (in French), Rev. Metall, 49, 111-Til (1952) (Experimental, Phase Relations, Magn. Prop., Meehan. Prop., 15) [1952Pal] Palmer, E.W., Wilson, F.H., Constitution and Properties of some Iron-Bearing Cupro-Nickels , Trans. Amer. Inst. Min. Met Eng., 194, 55-64 (1952) (Experimental, Meehan. Prop., Morphology, Phase Relations, 8)... 

Fra] Fraker, A.C., Stadelmaier, H.H., The q Carbides of Molybdenum-Iron, Molybdenum-Cobalt and Molybdenum-Nickel , Trans. AIME, 245, 847-850 (1969) (Phase Diagram, Crys. Structure, Experimental, Morphology, 20)... 

While many other metals can be used for transmetalation from alkyl- and alkenylzirconocenes [4], the synthetically most important protocols include cross-couplings after zirconium palladium and zirconium- nickel trans-metalations, and carbon-carbon bond formation after zirconium zinc and zirconium copper transmetalations. Recent advances in these transformations and their synthetic scope are discussed in more detail below. 

Twelve-membered rings have been obtained using coordination catalysts. The transJmns,ds-cyc. ododec2Lti ien.e has been prepared with a tetrabutyl titanate—diethylalurninum chloride catalyst (48,49) and with a chromium-based system (50). The trans,trans,trans-isom.e-i. has been prepared with a nickel system. 

K. M. Gorbunova and A. A. Nikiforova, Phjsiochemical Principles of (Chemical) Nickel Plating Academy of Sciences, Moscow, 1960 (Engl, trans. available from U.S. Government Office of Technical Services, Washington, D.C., 1963). 

Deuterium [7782-39-0] M 4. Passed over activated charcoal at -195° [Maciver and Tobin J Phys Chem 64 451 I960], Purified by diffusion through nickel [Pratt and Rogers, J Chem Soc, Faraday Trans 192 1589 1976], Always check deuterium for radioactivity to find out the amount of tritium in it (see D2O below). 

Among the J ,J -DBFOX/Ph-transition(II) metal complex catalysts examined in nitrone cydoadditions, the anhydrous J ,J -DBFOX/Ph complex catalyst prepared from Ni(C104)2 or Fe(C104)2 provided equally excellent results. For example, in the presence of 10 mol% of the anhydrous nickel(II) complex catalyst R,R-DBFOX/Ph-Ni(C104)2, which was prepared in-situ from J ,J -DBFOX/Ph ligand, NiBr2, and 2 equimolar amounts of AgC104 in dichloromethane, the reaction of 3-crotonoyl-2-oxazolidinone with N-benzylidenemethylamine N-oxide at room temperature produced the 3,4-trans-isoxazolidine (63% yield) in near perfect endo selectivity (endo/exo=99 l) and enantioselectivity in favor for the 3S,4J ,5S enantiomer (>99% ee for the endo isomer. Scheme 7.21). The copper(II) perchlorate complex showed no catalytic activity, however, whereas the ytterbium(III) triflate complex led to the formation of racemic cycloadducts. 

In the presence of bis(lriphenylphosphane)nickel dichloride both tram-1 and m-1 react with methylmagnesium bromide affording cis-2, trans-2 and 3 in a 19 1 5 ratio72c. It should be noted that the methyl group is introduced at the sterically more hindered carbon and this... 

In Gegenwart von Tetrakis-[pyridin]-nickel-diperchlorat oder Nickel(II)-chlorid in Athanol mit Tetrabutylammonium-perchlorat als Leitsalz erhalt man unter partieller Hy-drierung und Oligomerisation aus Butadien-(1,3) all-trans-Hexadecatetraen-(1,6,10, J4) in Gegenwart von Bis-[triphenylphosphin]-nickel(II)-chlorid wird Octatrien-(l,3,7) er-halten4. 

The reductive amination of ketones can be carried out under hydrogen pressure in the presence of palladium catalysts. However, if enantiopure Q -aminoketones are used, partial racemization of the intermediate a-amino imine can occur, owing to the equilibration with the corresponding enam-ine [102]. Asymmetric hydrogenation of racemic 2-amidocyclohexanones 218 with Raney nickel in ethanol gave a mixture of cis and trans 1,2-diamino cyclohexane derivatives 219 in unequal amounts, presumably because the enamines are intermediates, but with excellent enantioselectivity. The two diastereomers were easily separated and converted to the mono-protected cis- and trans- 1,2-diaminocyclohexanes 220. The receptor 221 has been also synthesized by this route [103] (Scheme 33). 

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