Arylations tris phosphite

C-H Arylation. Tris(l,l,l,3,3,3-hexafluoro-2-propyl)-phosphite (P[OCH(CF3)2]3) serves as a ligand in C-H activation reactions of aromatic compounds. For exartple, under the catalytic influence of RhCl(CO) P[OCH(CF3)2]3 2 and Ag2C03, the direct arylation of heteroarenes and arenes takes place with iodoarenes to afford a range of biaryls in good yields and with high selectivity. Thiophenes (eq 1), furans, pyrroles, indoles, and alkoxybenzenes are viable in this reaction. Instead of heteroarenes or arenes, allylsilanes also react with iodoarenes in the presence of RhCl(CO) P[OCH(CF3)2]3 2 catalyst to furnish the corresponding arylation product (eq 2) ... 

Tris(fluorosulfuroyl)fluoromethane (329) reacted with bis(diethylamido)benzyl phosphite to yield an intermediate (330) which extruded a molecule of SO2 to give as final product the bis(fluorosulfonyl) compound (331). The kinetics and mechanism of the reaction of fluorinated tricoordinate phosphorus compounds (332) and aryl 2,2,2-trifluoroethyl sulfenates (333) have been reviewed. ... 

Representative compounds of importance in polypropylene stabilization are tris( mixed nonyl phenyl) phosphite and dilauryl thiodipropionate-(DLTDP). The aryl phosphite is used in film grade resins and in other... 

The results are shown in Figure 1. PPP was comparable with the tris(nonylphenyl) phosphite in preventing process degradation, although it wasn t quite as effective. The unstabilized base resin, however, became soupy, discolored, and had a melt flow rate of more than 10 after four passes. Aryl phosphite and the PPP gave considerably less discoloration, and melt flow readings of 3.9 and 4.7, respectively, after four passes through the extruder. 

Tetracarbonyl cations [Cr(CO)4(L2)]+, where L2 represents arylphosphines, alkyl, or aryl phosphites, or a bidentate ligand with phosphorus or arsenic donor atoms, have been produced by both chemical and electrochemical means. However, oifly one of these complexes, namely, tra i -[Cr(CO)4(PPh3)2]+, is stable enough to be isolated as the perchlorate salt. Exposure to light and moisture produces tra i -Cr(CO)4(PPh3)2 via disproportionation. Just as easily isolated, but somewhat less sensitive, are the [Cr(CO)3(PR3)3]+ cations. " Oxidation with a silver ion or NO+ converts the /uc-(R3 = Me2Ph, (OMe)3) and mer-(R3 = (OMe)3, (OMe)2Ph, (OPh)3) complexes into Cr products with mer structures. Light and heat promote the formation of reduced wer-Cr(CO)3 (PR3)3. These tetra(carbonyl) and tri(carbonyl) cations have been the subject of ESR spectroscopy and theoretical study. 

Treatment of aryl tellurium halides with base (ethanolic potassium hydroxide , aqueous sodium hydroxide, triethylamine , tris[(-propyl] phosphite , triphenylphosphane ) leads to the formation of diaryl ditellurium compounds (p. 273). In the hydrolytically induced disproportionation reactions, aryl tellurinic acids are the other tellurium-containing products ... 

Organophosphorus compounds (OPs) are utilized on a large scale as flame retarding agents and plasticizers in a variety of products, such as plastic materials, rubbers, varnishes, lubricants, hydraulic fluids, and other industrial applications. This family of chemicals consists of alkylated and arylated phosphate or phosphonate esters and related compounds such as phosphites, phosphines, and related dimeric forms as well as ionic forms (Figure 31.2). " The low volatility of phosphoric acid and derivatives makes it the preferred choice of the phosphorus based FRs. These FRs are most effective in polymers that char readily. Also halogenated phosphate esters, such as tris(l-chloroisopropyl) phosphate (TCPP), and tris(2-chloroethyl) phosphate (TCEP), are widely used. These combine the properties of both the halogen and the phosphorus compounds. 

One might expect that a phosphorus reagent having for R an aryl group activated for bimolecular nucleophilic substitution (68) by electron- withdrawing substituents might participate in a Michaelis-Arbuzov reaction. Kamai and Koshkina (159), who prepared a number of chloro-and nitro-substituted derivatives of triphenyl phosphite, found this to be the case for both ortho and para isomers of tris(monochlorophenyl) phosphite, which reacted with alkyl halides to furnish phosphonates. On the other hand, tris(2,4,6-trichlorophenyl) phosphite and tris(2,4-dichlorophenyl) phosphite (155) gave only complexes with methyl iodide however, lower reaction temperatures were employed. 

The Michaelis-Arbuzov-like coupling of aryl bromides and tris(trimethylsilyl) phosphite occurs quite quickly in the presence of NiCl2 at 150 for pentachloro- and pentafluoro-pyridines, the coupling takes place at the 4-position, but the presence of a CN... 

Apart from palladacycles, a number of catalyst systems are currently known that show productivities up to 100,000 for Heck and Suzuki reactions of all kinds of aryl bromides. It is important to note that coupling reactions of electron-deficient aryl bromides (e.g., 4-bromoacetophenone), which are often used in academic laboratories, are not suitable as test reactions to judge the productivity of a new catalyst, because simple palladium salts without any Ugand give turnover numbers up to 100,000 with these substrates. Recently, palladium complexes in combination with sterically congested basic phosphines (e.g., tri-tcrt-butylphosphine), carbenes, and also phosphites led to productive palladium catalysts for the activation of various aryl chlorides. 

Dietz [51, 52] demonstrated that use of phosphites as additives in the reprocessing of post-consumer scrap PET resulted in reduction of discoloration, lowered development of acid end groups, and reduced acetaldehyde formation. Particular additives investigated were tris(2,4-di- -butylphenyl)phosphite, distearylpentaerythritoldiphosphite and bis(2,4-di- butylphenyl)pentaerythritoldiphosphite. The use of aryl phosphites for this purpose was also examined by Solera [53] and Pfaendner and co-workers [54]... 

The air-stabilities of the complexes in Table I vary widely. Isocyanide complexes and complexes of the alkyl phosphines are very air sensitive or pyrophoric. The aryl phosphine complexes are moderately air sensitive the phosphite complexes can be handled in air but should be stored in an inert atmosphere. The phosphite complexes are insoluble in polar solvents such as alcohols and water, and soluble in hydrocarbons. Aryl phosphine complexes are soluble in aromatic solvents or tetrahydrofuran and insoluble in alkanes and alcohols. The alkyl phosphine complexes are soluble in ethers and hydrocarbons the triethylphosphine complex dissociates to the deep-purple tris complex, and is protonated by alcohols. 

The Hiyama-Hatanaka cross-coupling reaction is a more recent arylation coupling reaction that was reported by these workers in 1988 [12e, 31]. These workers demonstrated that trimethylsilylethy-lene reacts with aryl halides in the presence of a Pd(0) catalyst, a base, and a source of fluoride ion to give styrene derivatives [12e]. The source of Pd can be (it-CjHjPdCOj, Pd(Ph3P)4, or even Pdjfdbalj the base could be a hydroxide, an acetate, a phosphane, or a phosphite and the source of the fluoride ion could be tris(diethylamino)sulfonium difluoro(trimethyl)silicate (TASF), tetrabutylammonium fluoride (TBAF) or even KF (See Scheme 1.14a). The role of this reagent is shown in the catalytic cycle... 

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