Hydrocarbons, hydrocarbon phosphonium salts

Benzylphosphonates have been used in the synthesis of polymethoxy-stilbenes and of (174) and (175). The hydrocarbon (175) obtained in this way was much easier to purify than that prepared using the bis-phosphonium salt. 

The fluorescence of a range of polycyclic aromatic hydrocarbons is found to be quenched in the presence of alkyltriphenyl-phosphonium salts via electron-transfer from the hydrocarbon to... 

Phosphonium salts, e.g. (124), derived from polynuclear hydrocarbons and used as intermediates in helicine synthesis, have been prepared by the reaction of the appropriate benzylic alcohol with triphenylphosphine hydrobromide.120 Similarly, the salt (125), of value as an intermediate in carotenoid synthesis, has been prepared by the reaction of a precursor allylic alcohol with triphenylphosphine hydrobromide.121 Bromomethyl a-diketones react with triphenylphosphine to form... 

The Heck reaction is a C-C coupling reaction where an unsaturated hydrocarbon or arene halide/triflate/sulfonate reacts with an alkene in presence of a base and Pd(0) catalyst so as to form a substituted alkene. Kaufmann et al. showed that the Heck reaction carried out in presence of ILs such as tetra-alkyl ammonium and phosphonium salts without the phosphine ligands, resulted in high yields of product. They attributed the activity to the stabilizing effect of ammonium and phosphonium salts on Pd(0) species. Carmichael et al. used ionic liquids containing either A,A -dialkylimidazolium and A-alkylpyridinium cations with anions such as halide, hexafluorophosphate or tetrafiuoroborate to carry out reactions of aryl halide and benzoic anhydride with ethyl and butyl acrylates in presence of Pd catalyst. An example of iodobenzene reacting with ethyl acrylate to give trans-et vy cinnamate is shown in Scheme 14. 

For the phosphonium salt, [(C4)4P][CiS03], in toluene and ethylbenzene, the immiscibility was observed only in a very narrow area of the hydrocarbon high mole fraction [54]. 

The mono-substituted butadiene 66 was needed with a trans alkene in the middle. So disconnection 61a looks good and the allyl phosphonium salt 65 did indeed give E-66 though in poor yield. These low molecular weight hydrocarbons are difficult to isolate as they are volatile. 

The following reaction between a phosphonium salt, base, and an aldehyde gives a hydrocarbon Q Hi2 with the 200 MHz NMR spectrum shown. Give a structure for the product and comment on its stereochemistry. You are not expected to discuss the chemistry ... 

The alkaline cleavage of quaternary phosphonium salts is a well-documented reaction, which represents one of the most important methods for preparing phosphine oxides. Hydrocarbons are the other products of this reaction (equation 8). ... 

A cyclic phosphonium salt fJ) was obtained, in addition to other products, when red phosphorus was treated with 1,4-diiodobutane at 210 °C for 3 h in the presence of catalytic amounts of iodine Alkylation of elemental phosphorus with hydrocarbon halides are summarized in Table 1. 

The alkaline hydrolysis of phosphonium salts gives phosphine oxides and hydrocarbons resulting from the most stable carbanions in each case. O Benzyl tris(2-pyridyl)phosphonium bromide (17) undergoes rapid alkaline hydrolysis at room temperature to give good yields of benzylbis(2-pyridyl) phosphine oxide and pyridine. ... 

Figure 25 shows a specific example of extraction of furfural using a hydrocarbon solvent. Sharma (1988) has considered several other examples of reactions which would profit from introduction of an additional phase. Sharma (1988) has also provided several examples of liquid-liquid reactions of industrial interest which could benefit from the addition of substances such as quaternary ammonium and phosphonium salts, crown ethers and trialkyl amines, which function as phase transfer catalysts, significantly enhancing the reaction rates and in some cases improving the reaction selectivity. 

In the presence of hydroxyl ions phosphonium salts decompose preferentially into the phosphine oxide and a hydrocarbon or into the alkylidenephosphor-ane.90 However, (alkoxycarbonylalkyl)phosphonium salts (readily obtained from <%-halo esters and tributyl- or triphenyl-phosphine) decompose when... 

The liquid clathrate phase will dissolve substances that act as olefin hydrogenation catalysts, creating homogeneous hydrogenation catalysts.Polymerization catalysts comprised of stable liquid clathrate aluminoxane, aromatic solvents, and organic, inorganic, or organometallic compounds were described.Liquid clathrate compositions comprised of a metal halide, a quaternary ammonium salt, a quaternary phosphonium salt, or a ternary sulfonium salt an aluminum trihalide and an aromatic hydrocarbon have proven useful as reusable aluminum catalysts in Friedel-Crafts reactions. 

For the synthesis of spheroidene (97) two different phosphonium salts are needed. The C15-phosphonium salt 70 for the hydrocarbon end group is prepared in one step from commercially available (all- )-farnesol (71) and triphenylphosphine hydrobromide [61] (Scheme 22). 

Alkyl phosphonium halides are decomposed by strong heating to give tertiary phosphines (6.32), whereas phosphonium hydroxides easily give phosphine oxide and hydrocarbon (6.109). The action of heat on triphenyl ((-alkoxycarbonyl alkyl) phosphonium salts is to produce ylids (6.391) (Section 6.10). 

Under the action of water, most phosphonium ylids wiU undergo hydrolysis to hydrocarbon and phosphine oxide in the same way as phosphonium salts (6.102, 6.371), which are most certainly formed as intermediates. 

Butyllithium is an unsuitable base on account of its sensitivity to air and moisture. In the process the phosphonium salt precursor (formed from the alcohol, Ph3P and hydrogen halide), together with aldehyde in methanol, are treated with methanolic sodium methoxide at — 30 C. After reaction the solution is neutralized with dilute sulphuric acid, the Vitamin A ester extracted into a hydrocarbon solvent and isolated after removal of solvent by distillation. 

A very simple process can be used for the synthesis of the C20 hydrocarbon axerophthene (568) (Newton et aL, 1978). When retinol (1), retinyl methyl ether (571), or retinyl acetate (9) was reacted with triphenylphosphine and an acid, a C20 phosphonium salt [for e.g., the hydrogen sulfate (95) (Nurrenbach and Pommer, 1969 Surmatis etaL, 1969)], was obtained (Pommer, 1960 Schwieter et aL, 1966). Alkaline hydrolysis of this product gave axerophthene (568). 

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