Dichlorobis nickel

Neopentyl sulfides, 58, 146 Neopentyl tosylate, 58, 147 Nickle cathode, 57, 92 Nickle(U) chloride hexahydrate, 58, 128 Nickel, dichlorobis(triphenylphosphine), 58, 133... 

Chloromethyltrimethylsllane Silane, (chloromethyl)trimethyl- (8,9) (2344-80-1) Dichlorobis(triphenylphosphine)nickel Nickel, dichlorobis(triphenylphosphine)-... 

Dimethyl-I,l -biphenyl has been prepared by a wide variety of procedures, but few of these are of any practical synthetic utility Classical radical biarjl syntheses such as the Gomberg reaction or the thermal decomposition of diaroyl peroxides give complex mixtures of products m which 4,4 dimethyl-l.l -biphenyl is a minor constituent A radical process maj also be involved in the formation of 4,4 dimethyl-1, l -biphenyl (13%) by treatment of 4-bromotoluene with hydrazine hydrate 5 4,4 -Dimethyl-l,l -biphenyl has been obtained in moderate to good yield (68-89%) by treatment of either dichlorobis(4-methyl phenyl)tellurium or l,l -tellurobis(4-methylbenzene) with degassed Raney nickel in 2 methoxyethyl ether 6... 

A complex reaction takes place when dichlorobis(triphenylphosphine)-nickel (5) is treated with excess methylmagnesium bromide in ether. Detectable amounts of benzene, toluene, and biphenyl are formed, together with mixed phosphines. Nickel appears to be necessary for the substitution reaction since triphenylphosphine alone does not react with the Grignard reagent. 

Tris (triphenylphosphine) nickel, tris (tri-p-tolylphosphine) nickel, and bis (1,3-diphenylphosphinepropane) nickel proved to be good catalysts, the first being slightly more effective. The tricyclohexylphosphine complex was a very poor catalyst, and bis (cyclooctadiene) nickel did not catalyze cyanation. Cyanation of several substituted aromatic halides in the presence of Ni[P(C6H5)3]3 prepared by reducing dichlorobis (triphenylphosphine) nickel (II) 2 with a powdered manganese iron (80 20) alloy (Reaction 3) is reported in Table II. 

Dichlorobis(triphenylphosphine)-palladium(II), 103 Methyl (trifluoromethylsulfonyl)-methyl sulfone, 193 Nickel carbonyl, 198 Palladium(II) acetate, 232... 

The synthesis and reactivity of a series of nickelacyclopentane compounds with a range of tertiary phosphine ligands was reported by Grubbs et ol. Compounds of type 69 were prepared by the reaction of 1,4-dilithiobutane with the appropriate dichlorobis(tertiaryphosphine)nickel(II) complex, and isolated as yellow crystals in ca. 40% yield78 (dppe = bis(diphenyl) (phosphinoethane). 

Dichlorobis(tricyclohexylphosphine)nickel is first prepared by the following procedure, which is a slight modification of the original synthesis of Turco, Scatturin, and Giacometti.7 A solution of tricyclohexylphosphine (14.0 g, 0.050 mol) in benzene (50 mL) and ethanol (300 mL) is added slowly to a solution of nickel dichloride hexahydrate (5.9 g, 0.025 mol) in ethanol (100 mL) at room temperature in a nitrogen or an argon atmosphere. A reddish, crystalline precipitate deposits immediately. After the addition is complete, the mixture is left for a few hours, then the product is filtered off, washed with ethanol, and dried in vacuo. (Yield 16.4 g 95%.)... 

Powdered sodium tetrahydroborate(l -) (0.37 g, 0.01 mol) is added in three portions at about 30-min intervals to a suspension of dichlorobis(tri-isopropylphosphine)nickel (4.5 g, 0.01 mol) in diethyl ether (300 mL) and 95% ethanol (50 mL) in a 500-mL three-necked flask with an argon inlet and a gas bubbler vented to the hood. The reaction mixture is stirred with a magnetic stirring bar at 20° for approximately 5 hr. Gas evolution is observed, and the nickel complex dissolves gradually. After all the nickel compound is dissolved, the solution is filtered into a 500-mL two-necked flask and the solvent is removed under reduced pressure. The yellow residue is extracted with petroleum ether (200 mL), and the solution is washed with two 50-mL portions of water. The petroleum layer is separated, dried with 15 g of anhydrous sodium sulfate, which is washed with two 10-mL portions of the solvent which are added to the petroleum extract the combined extract is then filtered and concentrated in vacuo. The saturated solution (approximately 100 mL) is cooled to —78° in a Dry lce-2-propanol mixture overnight. The crystals which are formed are filtered, washed with a small amount (approximately 10 mL) of petroleum ether at 0°, and dried in vacuo to give brown crystals, mp 65-66° (decomposes). (Yield 2.5 g, 60%.) Anal. Calcd. for Cl8H43ClNiP2 C, 52.1 H, 10.4 Ni, 14.1. Found C, 52.3 H, 9.7 Ni, 14.1. 

Dichlorobis(cyclopentadienyl)titanium-Lithium borohydride, 146 Dichlorobis(cyclopentadienyl)titanium-Trlalkylaluminum, 146-147 Dichloro (1,1 -bis(diphenylphosphine)fer-Tocene] palladium(II), 147 Dichlorobis triphenylphosphine)nickel(II),... 

Catalytic hydrosilylation of alkenes performed in the presence of a chiral catalyst results in the formation of chiral silanes. Initially platinium catalysts of the type L PtCl2, L = (/ )-benzyl-(methyl)phenylphosphine (BMPP) or (/ )-methyl(phenyl)propylphosphine and 1,1-disubstituted prostereogenic alkenes, such as a-methylstyrene, 2,3-dimethyl-l-butene and 2-methyl-l-butene, were used however, the stereoselectivity was low4,5. A slightly higher stereoselectivity is obtained when dichlorobis[(/ )-benzyl(methyl)phenylphosphine]nickel [Ni(BMPP)2Cl2] is used as the catalyst. Note that two chiral silanes are formed in this reaction, both of which are products of anti-Markovnikov addition. The major product is the expected dichlorosilane 3, while the byproduct is an anomalous chlorosilane 4 both products were separated by fractional distillation and the major product methylated to give the trimethylsilanes 56 7. 

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