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Phosphine production

If aromatic aldehydes or ketones are used, the tertiary phosphine product sometimes rearranges to a mixed phosphine oxide. [Pg.380]

Examples of the intermolecular C-P bond formation by means of radical phosphonation and phosphination have been achieved by reaction of aryl halides with trialkyl phosphites and chlorodiphenylphosphine, respectively, in the presence of (TMSlsSiH under standard radical conditions. The phosphonation reaction (Reaction 71) worked well either under UV irradiation at room temperature or in refluxing toluene. The radical phosphina-tion (Reaction 72) required pyridine in boiling benzene for 20 h. Phosphinated products were handled as phosphine sulfides. Scheme 15 shows the reaction mechanism for the phosphination procedure that involves in situ formation of tetraphenylbiphosphine. This approach has also been extended to the phosphination of alkyl halides and sequential radical cyclization/phosphination reaction. ... [Pg.152]

This reaction was most efficiently catalyzed by platinum 4 mol% of PtLs gave complete conversion of PH(CH2CH2CN)2 to L after 6 h. The rate depended on solvent, increasing in the order acetonitrile < acetone dimethylsulfoxide (DMSO). The solvent also affected the selectivity in acetonitrile, less than 5% of a minor phosphine product, proposed to be the telomer 1 (Scheme 5-4), was produced. More of this by-product was formed in acetone (20%), while in DMSO it was the major product (60%) [8]. [Pg.145]

Similar catalytic reactions allowed stereocontrol at either of the olefin carbons (Scheme 5-13, Eqs. 2 and 3). As in related catalysis with achiral diphosphine ligands (Scheme 5-7), these reactions proceeded more quickly for smaller phosphine substrates. These processes are not yet synthetically useful, since the enantiomeric excesses (ee s) were low (0-27%) and selectivity for the illustrated phosphine products ranged from 60 to 100%. However, this work demonstrated that asymmetric hydrophosphination can produce non-racemic chiral phosphines [13]. [Pg.151]

The initial phosphine products were converted to the phosphine sulfides to protect them from oxidation and readily reconverted to the free phosphines by Raney nickel desulfurization.77... [Pg.126]

Devai I, Delaune RD. 1995. Evidence for phosphine production and emission from Louisiana and Florida marsh soils. Organic Geochemistry 23 277-279. [Pg.264]

Hydroxy-phosphines undergo benzoylation with o-sulfobenzoic anhydride in the presence of bases (Na2C03 or BuLi) affording sulfobenzoylated phosphine products. In such a way several mono- and dihydroxy phosphines could be made soluble in water, exemplified by the chiral bisphosphines 53. It should be noted, that this general method allows the preparation of water-soluble sulfonated derivatives of acid-sensitive phosphines, such as DIOP, too, which are not accessible via direct sulfonation [56]. [Pg.27]

The H-P bond in hypophosphites appears much more reactive than that in the phosphinate products the reactions of alkynes do not form symmetrically dialkenyl-substituted phosphinate R2P(0)(0R ) (R=alkenyl group). [Pg.53]

In the oxidative addition of a fluorinated aryl iodide, 43, to Pd(PPh3)2 (Figure 1.12) [29], F NMR has been used to follow the ds-to-trans isomerization of the ds-bis-phosphine product, 44, to the trans-isomer, 45. The F NMR kinetic study reveals a first order dependence for the rate of isomerization on the concentration of 44. An application of a F NMR kinetic study to the evaluation of the... [Pg.10]

Table 7 Synthesis of a-Methylenelactonesa Substrate Phosphine Product... Table 7 Synthesis of a-Methylenelactonesa Substrate Phosphine Product...
Reactions of R2PCI or RPCI2 with LiBH yield only the borane-coordinated phosphine products". [Pg.106]

In contrast, LiAlH reduction of (Me3Si)jNPNSiMe3 followed by reaction workup in the presence of HjO (or D O) yields a bis(amino)phosphine product . [Pg.110]

Taillefer et al. have reported a one-pot method for the preparation of a, 3-unsaturated organophosphorus compounds through the reaction of lithium diphenylphosphonium diylides with phosphorus electrophiles and aldehydes. In the first step, treatment of diylides (91) with chlorodiphenylphosphine results in the formation of mono-ylide intermediates (92) and (93). Subsequent addition of aldehyde (94) produces either alkenes (95) or phosphines (96) (Scheme 22). The product obtained is critically dependent upon the nature of the ylide substituents and the aldehyde employed. For example, non-stabilised ylide (91a) reacts with chlorodiphenylphosphine and aromatic, heteroaromatic or enolisable aldehydes (94a-f) producing the corresponding phosphines (96), predominantly as the Z isomer. However, with 4-phenylcyclohexanone the only product obtained from (91a) is the alkene, (4-methylenecyclohex-l-yl)benzene. Non-stabilised ylide (91b) reacts with chlorodiphenylphosphine and benzaldehyde (94a) to give primarily alkene product whereas para-nitrobenzaldehyde (94c) yields only the phosphine product. Semi-stabilised ylide (91c), and stabilised ylide (91d), react... [Pg.303]

The results from reactions with phenyllithium and phenylsodium indicated that the phosphorus-derived organophosphides were of complex structure (6). The alkyl halide reactions demonstrated the presence of structural units having two phenyl groups bonded to phosphorus, yet only small yields of diphenylphosphine were obtained on hydrolysis. Lithium diphenylphosphide was thus ruled out as an important intermediate, since it hydrolyzes cleanly to diphenylphosphine. Moreover, hydrolysis of the organophosphide from plienylsodium and phosphorus failed to give simple phosphine products at all, but reaction of the sodium... [Pg.3]

Binuclear reductive elimination processes from saturated hydride complexes to yield 17-electron products have been established for electrocatalytic dihydrogen evolution systems [6, 129]. Analogous processes have been shown to occur from 19-electron hydride complexes to yield saturated products. Compounds [CpCoH(PR3)2] (R = Ph, Et, OMe) and [CpCoH(L-L)]+ (L-L = dppe, dmpe, and Ph2PCH=CHPPh2), undergo one-electron reduction processes followed by the production of H2 and the expected 18-electron Co(l) bis-phosphine products. In the presence of protons, catalytic H2 evolution was shown [25]. Although the one electron reduction process for the monophosphine derivatives is irreversible at all investigated scan rates (possibly due to phosphine decoordination from the... [Pg.174]

Preparation of poly(ethylenediphenylphosphine) PE-PPh2 [152] To a suspension of oligomer (30 mmol) was added (10.6 mL, 13.3 g, 60 mmol) of chlorodiphenylphosphine at 25 °C. After stirring for 1 h the mixture was heated to 90 °C and vigorously stirred for an additional 12 h. Cooling precipitated the crude product which was placed in Soxhlet apparatus and extracted into the toluene solution. Cooling the hot toluene solution produces a crude phosphine product free of any insoluble salts. This substance was suspended in toluene and allowed to react with trichlorosilane (19.5 g, 145 mmol) for 24 h at 25 °C. The bulk of the excess trichlorosilane was removed under reduced pressure. After the solid oligomer was isolated by filtration, it was suspended in KOH (150 mL... [Pg.489]

In a fire or during waste incineration, P-red is easily oxidised to phosphorus oxides, which do not lead to phosphine production. The phosphorus oxides remain as polymeric phosphoric acid or phosphates in the bottom ash or can be removed in the flue gas treatment system of incinerators. [Pg.34]

As expected, the reaction rate is faster for smaller phosphines and in many cases other phosphine products are formed, identified by P NMR spectroscopy, especially with dcpe as the ligand in the catalyst. Hydrophosphination also occurs for most of the substrates in the absence of catalyst but more slowly than in the catalysed process. [Pg.296]

Upon protonating salts la and Ic in the presence of mono-dentate phosphines, an interesting balance of reactivity was observed. When using the secondary phosphine PHPh2 the expected bis-phosphine product 4c was obtained from protonation of Ic. Simply replacing this phosphine in the reaction mixture with the tertiary phosphine PPha afforded complex 7b, in... [Pg.29]

Metal substituent phosphine product product product product... [Pg.29]

Deoxygenation and Desulfurization. Hexachlorodisilane has been shown to effect the stereospecific reduction of phosphine oxides to phosphines with inversion of configuration (eq 1 ), although short reaction times are required to prevent chemical racemization of the phosphine products under the reaction conditions. This protocol complements trichlorosilane which, under appropriate conditions, reduces phosphine oxides with retention of configuration. Reductions of bridged bicyclic phosphine oxides and cyclic halophospholene oxides by hexachlorodisilane have also been reported. [Pg.309]


See other pages where Phosphine production is mentioned: [Pg.153]    [Pg.31]    [Pg.192]    [Pg.93]    [Pg.96]    [Pg.397]    [Pg.193]    [Pg.1854]    [Pg.146]    [Pg.323]    [Pg.64]    [Pg.1853]    [Pg.193]    [Pg.146]    [Pg.3647]    [Pg.395]    [Pg.78]    [Pg.34]    [Pg.1087]    [Pg.1090]    [Pg.1090]    [Pg.250]    [Pg.31]    [Pg.126]    [Pg.1087]    [Pg.1090]    [Pg.1090]   
See also in sourсe #XX -- [ Pg.421 , Pg.500 ]




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