Phosphines acetone

The M4L6 anionic host complex 4 by Raymond et al. efficiently traps and stabilizes reactive gnests, such as a tropylium cation, " phosphine-acetone adducts, iminium... 

In general, peroxomonosulfates have fewer uses in organic chemistry than peroxodisulfates. However, the triple salt is used for oxidizing ketones (qv) to dioxiranes (7) (71,72), which in turn are useful oxidants in organic chemistry. Acetone in water is oxidized by triple salt to dimethyldioxirane, which in turn oxidizes alkenes to epoxides, polycycHc aromatic hydrocarbons to oxides and diones, amines to nitro compounds, sulfides to sulfoxides, phosphines to phosphine oxides, and alkanes to alcohols or carbonyl compounds. 

A mixture of l,4-dibromo-2,5-bis(3-sulfonatopropoxy)benzene 61 (0.78 g, 1.39 mmol), 60 (0.23 g, 1.39 mmol), Na2C03 (0.99 g) in doubly distilled water (47 mL), and DMF (20 mL) was heated at 85°C until the solids were completely dissolved. The resulting solution was cannulated to a 200-mL Schlenk flask with tris[(sulfonatophenyl)phosphine]palladium(0) (0.045 g) and the mixture was stined at 85°C for 10 h. The reaction mixture was concentrated to 25 mL by boiling and filtered. The filtrate was added dropwise to cold acetone (250 mL) to precipitate out the polymer. The polymer was collected by filtration, redissolved in a minimum of hot water, and reprecipitated by cooling. After repeating this procedure twice, the polymer was redissolved in distilled water and dialyzed for 72 h in 3500 gmol 1 cutoff membrane. After drying under vacuum, polymer 63 was obtained in 64% (0.42 g). 

Acetylene is a simple asphyxiant and anaesthetic. Pure acetylene is a colourless, highly flammable gas with an ethereal odour. Material of commercial purity has an odour of garlic due to the presence of impurities such as phosphine. Its physical properties are shown in Table 9.4. Acetylene, which condenses to a white solid subliming at -83°C, is soluble in its own volume of water but highly soluble in acetone. 

The rate of solvolysis of the phosphinic chlorides (83a, b) in trifluoro-acetic acid and aqueous acetone (the composition of the latter solvent being chosen such that the rate of S nI solvolysis of Bu Cl was the same in both) have been examined to assess the possible operation of an 5 n1(P) ionization mechanism. In the more nucleophilic aqueous acetone solvent,... 

It is often said that the property of acidity is manifest only in the presence of a base, and NMR studies of probe molecules became common following studies of amines by Ellis [4] and Maciel [5, 6] and phosphines by Lunsford [7] in the early to mid 80s. More recently, the maturation of variable temperature MAS NMR has permitted the study of reactive probe molecules which are revealing not only in themselves but also in the intermediates and products that they form on the solid acid. We carried out detailed studies of aldol reactions in zeolites beginning with the early 1993 report of the synthesis of crotonaldehyde from acetaldehyde in HZSM-5 [8] and continuing through investigations of acetone, cyclopentanone [9] and propanal [10], The formation of mesityl oxide 1, from dimerization and dehydration of... 

Interestingly, when analogous phosphine adducts were tested, very poor catalytic activity was obtained (Table 10.4, entries 6 and 7). On the other hand, the NHC-cationic complex [IrCp (ITM)(NCMe)2][OTf]2 25 proved highly efficient for the Oppenauer-type oxidation of a large range of secondary as well as primary alcohols in acetone (e.g.. Table 10.4, entries 4, 5, 8-10). 

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]. 

Table 10 Impact of the chelating phosphine on levels of enantioselectivity in rhodium-catalyzed intramolecular hydrosilylation with [Rh(P-P)(acetone)2]+.

The lustrous black crystals of trirhenium nonabromide are not rapidly degraded on exposure to the atmosphere the crystals can be stored over desiccants for months without evidence of decomposition. The bromide dissolves fairly slowly and sparingly in ether and acetone. In methanol, the bromide gives yellow-orange solutions, but it is solvolyzed within minutes. Similarly, the bromide dissolves in water at room temperature to yield a violet solution which darkens rapidly, yielding a black precipitate, presumably the hydrated dioxide.9 Contrary to published work,10 the bromide does dissolve in ammonia with solvolysis, as is evidenced by lines attributable to ammonium bromide in x-ray diffraction data of the solid residue recovered from liquid ammonia solutions.11 Trirhenium nonabromide reacts with Lewis bases such as phosphines and amines to form a series of complexes of the type (base) 3Re3Br9.6... 

The red and orange forms of RhCl[P(C6H5)3]3 have apparently identical chemical properties the difference is presumably due to different crystalline forms, and possibly bonding in the solid. The complex is soluble in chloroform and methylene chloride (dichloromethane) to about 20 g./l. at 25°. The solubility in benzene or toluene is about 2 g./l. at 25° but is very much lower in acetic acid, acetone, and other ketones, methanol, and lower aliphatic alcohols. In paraffins and cyclohexane, the complex is virtually insoluble. Donor solvents such as pyridine, dimethyl sulfoxide, or acetonitrile dissolve the complex with reaction, initially to give complexes of the type RhCl[P(C6H6)3]2L, but further reaction with displacement of phosphine may occur. 

A new class of phosphines (30) containing only an axial element of chirality (atropisomerism) has been made (253, 254). An in situ 1 1 rhodium/2,2-bis(diphenylphosphinomethyl)-1,1 -binaphthyl system (30a) hydrogenated a-acetamidocinnamic acid to a 54% ee (S) using 50 atm H2, the solvent not being recorded (253). The corresponding diphenyl-phosphinite system (30b) in toluene-acetone was particularly effective (76% ee) for hydrogenation (95 atm) of a-acetamidocinnamic and a-acet-amidoacrylic esters (254). 

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