Phosphine oxides arylation

A wide variety of high-performance polymeric materials have been synthesized by incorporating thermally stable moieties such as sulfone, ketone, or aryl or alkyl phosphine oxide in addition to the ether linkage in poly(arylene ether)s. 

Other phosphorous compounds, as shown in Table 8, were resolved by the same procedure. The three isomeric phosphinates 27b-d containing a methyl group attached to the aryl substituent could also be resolved, irrespective of the methyl position. From the related phosphine oxides 28a d, however, only those with R=H (28a) and R=m-CH (28c) could be well resolved no satisfactory resolution could be obtained for the other isomers of 28. The efficiency of the optical resolution of alkylaryl-substituted sulfoxides and selenoxides was found to depend similarly on the type of substitution on the aryl ring. 

Nickel and palladium complexes also catalyze the formation of the carbon-phosphorus bonds in phosphorus(V) and phosphorus(III) compounds. Indeed, this chemistry has become a common way to prepare phosphine ligands by the catalytic formation of phosphine oxides and subsequent reduction, by the formation of phosphine boranes and subsequent decomplexation, or by the formation of phosphines directly. The catalytic formation of both aryl and vinyl carbon phosphorus bonds has been accomplished. 

Thiophosphonate phosphinate phosphinothioc amide phosphine oxide Figure 8-4. Some Wittig reagents. Fg = H, alkyl, aryl, or other functional groups. 

Tan also found that guanidine 21, acting as a base to activate the o [3], X [3] tautomers of diaryl phosphine oxides, catalyzes the asymmetric phospha-Michael reachon of aryl nitroalkenes (Scheme 5.42) [76]. He later employed 21 to realize highly enantioselective Michael additions of dithiomalonate and 3-keto thioesters with a range of acceptors, including maleimides, cyclic enones, furanone, and acyclic 1,4-dicarbonylbutenes [77]. 

At low temperatures dioxetane adducts with trivalent phosphorus have been isolated by Bartlett and coworkers. These cyclic phosphoranes gradually decompose to give the corresponding epoxide and phosphine oxide (Scheme 39) (73JA6486). Aryl-substituted phosphines... 

Triarylphosphines were prepared by the reaction between lithium diphenylphosphide in THF and m-and p-iodotoluene (or the corresponding bromo compounds), 4-bromobiphenyl and p-dibromobenzene in yields of 70-80% (isolated after oxidation, as the phosphine oxides).143 The absence of cine substitution products is a synthetic advantage and would have been taken as a prima facie indication that the displacements are examples of the 5rn1 reaction, had the mechanism been recognized at the time. Operation of the radical ion mechanism in DMSO, or liquid ammonia, in which marginally improved yields are obtained, was confirmed by Swartz and Bunnett,48 but no extension to the scope of the reaction was made. Rossi and coworkers have developed a procedure for one-pot preparation of triarylphosphines starting from elemental phosphorus (Scheme 6).146 As an example of the synthesis of a symmetrical tri-arylphosphine, triphenylphosphine (isolated as its oxide) was obtained in 75% yield, with iodobenzene as the aryl halide (ArX in Scheme 6, steps i-iii only). Unsymmetrical phosphines result from the full sequence of reactions in Scheme 6, and p-anisyldiphenylphosphine (isolated as its oxide) was produced in 55% yield, based on the phosphorus used, when chlorobenzene (ArX) and p-methoxyanisole (AiOC) were used. 

Carbamoyl methyl Phosphine Oxide Derivatives The physicochemical properties of various aryl derivatives of CMPO have been investigated at the Vernadsky Institute of Geochemistry and Analytical Chemistry. Extraction of americium and lanthanides from nitric acid with solutions of diphenyl- and dibutyl-(diethylcarbamoylmethyl) phosphine oxides (Ph2Et2-CMPO and Bu2Et2-CMPO) in dichloroethane have been investigated as a function of the concentrations of the extractants and nitric acid (110, 111). The observed dependences are characterized... 

When the bis(pentahalophenyl)aurate(I) salt is treated with thallium(I) hexafluoropho-sphate in the presence of OPPh3, the phosphine oxide is incorporated into the polymeric chain affording species with different stoichiometry depending on the aryl group (see Scheme 6).151... 

Chan has reported that substitution of the 1,3-propa-dioxy ether linkage with a (25,35)-buta-dioxy ether linkage, as in 114, resulted in complete atropdiastereoselective coupling of the aryl units (Scheme 12.42). Reduction of the phosphine oxide (/ )-115 resulted in (R)-116 in 96% yield. This procedure eliminates a resolution step.140... 

Amino and functional aromatic phosphates, phosphonates, and phosphine oxides have also been used as reactive components to impart flame retardancy to cured epoxy resins. Phosphine oxides are particularly hydrolytically stable and several studies have been reported, for example, of the curing of epoxy resins with bis(aminophenyl) alkyl and aryl phosphine oxides65-67 (Structure 5.19). The relative performances of epoxies cured with aromatic diamine hardeners containing phosphine oxide, phosphinate, phosphonate, or phosphate units have recently been assessed.68 Aromatic phosphine oxides have been functionalized also with maleimide and hydroxyl groups for use as epoxy resin hardeners.69,70... 

Pd[P(o-tolyl)3]2] underwent oxidative addition of aryl halides to provide the unusual dimeric aryl halide complexes [Pd[P(o-tolyl)3](Ar)(Br) 2 (Eq. (44)) [77,102]. It is unusual for phosphine-ligated aryl halide complexes formed by oxidative addition to be dimeric. These oxidative addition products were isolated and structurally characterized. They remain dimeric in solution, as determined by solution molecular weight measurements, but react as the monomers, as described below. 

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