Phosphine, methyl compound with

The base-catalysed reaction of methyl phosphinate, MeOPfOjHj, with tetraphenyl-cyclopentadienone leads mainly to (75) via attack of H formed by decomposition of the phosphinate. No compounds with carbon-phosphorus bonds were detected, unlike reactions with other and P nucleophiles. 

Notable examples of general synthetic procedures in Volume 47 include the synthesis of aromatic aldehydes (from dichloro-methyl methyl ether), aliphatic aldehydes (from alkyl halides and trimethylamine oxide and by oxidation of alcohols using dimethyl sulfoxide, dicyclohexylcarbodiimide, and pyridinum trifluoro-acetate the latter method is particularly useful since the conditions are so mild), carbethoxycycloalkanones (from sodium hydride, diethyl carbonate, and the cycloalkanone), m-dialkylbenzenes (from the />-isomer by isomerization with hydrogen fluoride and boron trifluoride), and the deamination of amines (by conversion to the nitrosoamide and thermolysis to the ester). Other general methods are represented by the synthesis of 1 J-difluoroolefins (from sodium chlorodifluoroacetate, triphenyl phosphine, and an aldehyde or ketone), the nitration of aromatic rings (with ni-tronium tetrafluoroborate), the reductive methylation of aromatic nitro compounds (with formaldehyde and hydrogen), the synthesis of dialkyl ketones (from carboxylic acids and iron powder), and the preparation of 1-substituted cyclopropanols (from the condensation of a 1,3-dichloro-2-propanol derivative and ethyl-... 

Complexes of the type (L)AuR have been isolated with a large variety of donors L, including predominantly tertiary phosphines and isocyanides. The dinuclear complex (dppm)(AuMe)2 has been prepared by treatment of (dppm)(AuCl)2 with MeLi and structurally characterized.17 Examples (L)AuR with a carbene ligand L are also known. A simple methyl compound was prepared from the chloride complex with dimethylmagnesium (Equation (l)).18... 

Some research groups have investigated effects of substituents less common in organic chemistry. Quin and co-workers (127,128) determined a-SCSs of tri-and tetravalent phosphorus substituents in n-alkyl and cyclohexyl derivatives (Tables 5 and 6). The difference between -PH2 and -P(CH3)2 effects is easily explained by 3-SCS(CH3) (about 10 ppm for each methyl) this approach, however, is not satisfactory for P(OCH3)2 and PC12, since it would suggest a-SCS values of ca. 16 (found 21.4) and ca. 22 (found 32.5), respectively, for those two substituents. A stereochemical dependence similar to that of X = CH3 and OH seems to exist only for the primary phosphine (X = PH2) and the compounds with tetravalent phosphorus substituents, whereas the a-SCS values of the tri-valent functions are quite similar in many cases, regardless of their stereochemical position. 

Tris trifluoromethyl phosphine bums in air, but, unlike its methyl analogue, has not so far been found to form addition compounds with sulphur, carbon disulphide or silver iodide. With chlorine it forms the addition compound P(CF3)3Cl2 (b.p. 94°), and there is some indication that an addition compound of lower stability may be formed with bromine. With either of these halogens at higher temperatures, partial replacement of CF3 by halogen occurs and a similar reaction occurs with iodine, yielding some P(CF3)2l and P(CF3)l2. 

Similarly, the (5R)-5-deoxy-5-C-[(RS)-(ethoxy)phenylphosphinyl] compound 78 was prepared47 (69% yield) from 73 and ethyl phenyl-phosphinate (76). Also, condensation of the 3-O-methyl compound 74 with 75 and 76 (R" = OMe) respectively gave the (5RS)-5-C-[(RS)-phos-phinyl] compounds 79 (75% yield) and 80 (46% yield). 

Many diorganogold(III) compounds with tertiary phosphines and arsines are now known. It has been shown previously (Section 1II,B) that the reactions of [AuRL] complexes with alkyl halides usually produced [AuXL] and a triorganogold(lll) species. In certain instances, however, the expected [AuXR2L] compounds were formed (46, 194, 195), notably in the reactions of [AuMeL] (L = PMe3, PMe2Ph, or AsPh3) with methyl iodide. 

Many studies on the direct reaction of methyl chloride with silicon-copper contact mass and other metal promoters added to the silicon-copper contact mass have focused on the reaction mechanisms.7,8 The reaction rate and the selectivity for dimethyldichlorosilane in this direct synthesis are influenced by metal additives, known as promoters, in low concentration. Aluminum, antimony, arsenic, bismuth, mercury, phosphorus, phosphine compounds34 and their metal complexes,35,36 Zinc,37 39 tin38-40 etc. are known to have beneficial effects as promoters for dimethyldichlorosilane formation.7,8 Promoters are not themselves good catalysts for the direct reaction at temperatures < 350 °C,6,8 but require the presence of copper to be effective. When zinc metal or zinc compounds (0.03-0.75 wt%) were added to silicon-copper contact mass, the reaction rate was potentiated and the selectivity of dimethyldichlorosilane was enhanced further.34 These materials are described as structural promoters because they alter the surface enrichment of silicon, increase the electron density of the surface of the catalyst modify the crystal structure of the copper-silicon solid phase, and affect the absorption of methyl chloride on the catalyst surface and the activation energy for the formation of dimethyldichlorosilane.38,39 Cadmium is also a structural promoter for this reaction, but cadmium presents serious toxicity problems in industrial use on a large scale.41,42 Other metals such as arsenic, mercury, etc. are also restricted because of such toxicity problems. In the direct reaction of methyl chloride, tin in... 

Since only one methyl group is present in the phosphine part of adduct 5b, treatment of this compound with sec-butyllithium generates a single lithium derivative. Its reaction with selected aldehydes was tested as described in Scheme 5. 

With solutions of methyllithium in diethyl ether, either commercially available or prepared from lithium and methyl chloride, the checkers obtained lithium bis(lrimethylsilyl)phosphide-bisttetrahydrofuran) in only 40 or S0% yield. Therefore they advise preparing the compound with ii-butyllithium as described in the literature. The submitters report reproducible yields of 80%. Since excess tris(trimethyIsilyl)phosphine can easily be removed by recrystallization of the product, a slight deficiency of methyllithium is recommended. 

Although the starting methyl compound exists as a mixture of the geometrical isomers, the acetyl derivative occurs only with the acyl group cis to the nitrogen atom of the pyridine ligand. Kinetic studies have shown that the rate of CO insertion decreases as the Lewis base character of the tertiary phosphine increases. 

MERCURY(n) NITRATE (10045-94-0, anhydrous 7783-34-8, monohydrate) Hg(N03)2 H,0 Noncombustible solid. Light sensitive. A powerful oxidizer accelerates the burning of combustible materials. Violent reaction, or may form explosive materials, with reducing agents, including hydrides, nitrides, phosphorus, stannous chloride, and sulfides alkyl esters (forms explosive alkyl nitrates) combustible materials (especially if finely divided), phosphinic acid, hypophosphoric acid, metal powders petroleiun hydrocarbons. Forms heat- and/or shock-sensitive compounds with acetylene (forms explosive mercmy acetylide), ethanol and other alcohols (may form explosive mercury fulminates), ferrocene, isobutene, phosphine gas (forms heat- and shock-sensitive precipitate) potassiiun cyanide, sulfur. Incompatible with strong acids, acetic anhydride, ammonia, ammonium hexacyanofenate(II), organic azides, citric acid, hydrazinium perchlorate, isopropyl chlorocarbonate, nitrosyl perchlorate, sodium thiosulfate, sulfamic acid, thiocyanates, hydrozoic acid, methyl isocyanoacetate, sodium peroxyborate, trinitrobenzoic acid, urea nitrate. Aqueous solution corrodes metals. 

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