Bromo phosphine

A large variety of phosphorus derivatives can also be used. R2PCI can be used to give a quaternary phosphonium salt directly. Cyclic phosphinous chlorides are also effective and some examples have already been mentioned. Also, the different reactivities of chloro and bromo phosphines, the former giving largely 2-phosphoIene and the latter 3-phos-pholene derivatives, should be noted. 

Treatment of RuC13-a H20 with o-CH2=CHQH4EPh2 (E = P, As) gives [RuX2(L-L)2] (X = Cl, Br), The compound [RuCl2(SP)2] (E = P) exists in three isomeric forms all with both vinyl groups coordinated, two with tram chlorides and hence cis and trans phosphines, the most stable isomer having structure (203). The bromo phosphine and the arsine complexes exist only in form... 

Highly coloured anions are formed on the addition of alkali metals to triphenyl and pentaphe-nyl phospholes. Thus potassium reacts with pentaphenylphosphole in boiling dioxan to give potassium tetraphenyl phosphole containing the reddish violet anion indicated in (6.871). If water is added, 2,3,4,5 tetraphenylphosphole is obtained, and, with methyl iodide, 1,T dimethyl 2,3,4,5, tetraphospholium iodide, mp=297°C. Dibromo alkanes give bromo phosphines and with sulphur... 

On the other hand, the halohydrin (chloro and bromo) 908 is converted into a ketone via oxidative addition and //-elimination in boiling benzene with catalysis by Pd(OAc)2 and tri(o-tolyl)phosphine in the presence of K2C03[765,766],... 

More recent examples have employed a milder reagent system, triphenyl-phosphine and dibromotetrachloroethane to generate a bromo-oxazoline, which is subsequently dehydrohalogenated. Wipf and Lim utilized their method to transform intermediate 11 into the 2,4-disubstituted system of (+)-Hennoxazole k Subsequently, Morwick and coworkers reported a generalized approach to 2,4-disubstituted oxazoles from amino acids using a similar reagent combination, triphenylphosphine and hexachloroethane. ... 

Soderberg and coworkers have developed a palladium-phosphine-catalyzed reductive iV-het-eroannuladon of 2-nitrostyrenes forming indoles in good yields For example, reaction of 6-bromo-2-nitrostyrene with carbon monoxide in the presence of a catalytic amount of palladium diacetate (6 mol% and triphenylphosphine 124 mol% in acetonitrile at 30 gives 4-bromoindole in 86% yield fEq 10 62 Several functional groups, such as esters, ethers, bromides, tnflates, and additional nitro groups, have been shown to be compatible with the reaction conditions... 

A novel route to indoles and quinolines has been developed by sequential Wiltig and Heck reactions <96CC2253>. Thus, treatment of o-bromo- or iodo-lV-lrifluoroaceiylanilines (86) with a stabilized phosphorane affords the corresponding enamines 87 as a mixture of isomers. Cyclization to 88 is effected by heating with palladium acetate, tri phenyl phosphine, and bu.se. 

Primary phosphines (R-PHj) are an important ciass of compounds in organophosphorus chemistry. Aithough discovered over a century ago, their chemistry and appiications have gained prominence in recent years. This review discusses recent deveiopments on synthesis, moiecuiar structure, properties, and appiications of primary phosphines. In particular, discussions on synthesis and properties emphasize recent results from our laboratory on the chemical architecture of amide, thioether, and carboxylate functionalized primary bisphos-phines. The utility of bromo- and aminopropyl phosphines (X(CH2)3PH2 X=Br or NH2) as building blocks to produce designer primary phosphines that display exceptional oxidative stability is described. The review also discusses the utility of carboxylate functionalized primary phosphines for incorporation on to peptides and their potential applications in catalysis and biomedicine. 

Chapter 5 discusses recent developments in the synthesis and properties of primary phosphines. The utility of bromo and aminopropyl phosphines as well as that of carboxylate functionahzed primary bisphosphines, the latter for incorporation onto peptides and for their potential apphcations in catalysis, is under-hned by K. V. Katti, N. Pillarsetty and K. Raghuraman. 

Bromo-j3-nitrostyrene and triphenylphosphine in dry benzene gave the phosphonium bromide (47). Using methanol as the solvent, the rearranged product (48) was formed, possibly via an azirine intermediate. Substituted -bromo-/3-nitrostyrenes yield the phosphoranes (49) and a phosphonium salt. When the aryl group is electron-donating, the reaction follows a different course to form the styrene (50) by initial attack of the phosphine on halogen. 

Various mixed tridentate ligands with P,N,0/S/N donor sets have been explored in Ni11 chemistry. For example, condensation of 2-(diphenylphosphino)aniline with substituted (5-chloro-, 5-nitro, 5-bromo-, 5-methoxy-, and 3-methoxy-) salicylaldehydes yields (253).697 The deprotonated ligand coordinates through its P,N,0 donor set in a square planar geometry with some distortion, which is probably due to the bulk of the phosphine group and to the bite angle of the P,N chelate. 

Greater durability of the colloidal Pd/C catalysts was also observed in this case. The catalytic activity was found to have declined much less than a conventionally manufactured Pd/C catalyst after recycling both catalysts 25 times under similar conditions. Obviously, the lipophilic (Oct)4NCl surfactant layer prevents the colloid particles from coagulating and being poisoned in the alkaline aqueous reaction medium. Shape-selective hydrocarbon oxidation catalysts have been described, where active Pt colloid particles are present exclusively in the pores of ultramicroscopic tungsten heteropoly compounds [162], Phosphine-free Suzuki and Heck reactions involving iodo-, bromo-or activated chloroatoms were performed catalytically with ammonium salt- or poly(vinylpyrroli-done)-stabilized palladium or palladium nickel colloids (Equation 3.9) [162, 163],... 

Bromo-3-phenylpropane Benzene, (3-bromopropyl)- (8,9) (637-59-2) Triphenylphosphine Phosphine, triphenyl- (8,9) (603-35-0)... 

The rates of dehalogenation of a-bromo- and a-iodo-m-cyanobenzylphenyl-sulphones (89) by a number of sterically hindered phosphines in aqueous DMF have... 

That the second option can also be successfully used has recently been revealed by our synthesis of 2-methoxyphenazine (117) [90]. The reduction of o-bromo-o -nitrodiphenylamine 132 accessible via intermolecular Pd-catalyzed JV-arylation provides the o-amino-o -bromodiphenylamine 133, which can then be cyclized to give 117 in a Pd-catalyzed intramolecular AT-arylation by employing Pd2(dba)3 as the Pd complex and 134 as the phosphine ligand. It should be noted that the outcome of both the intermolecular and the intramolecular AT-arylations heavily depends on the appropriate choice of the Pd complex as well as the phosphine. Ether cleavage leads to 2-hydroxyphenazine (9). 

Also a pyridazin-3(2//)-one, namely 4-bromo-5-methoxy-2-(4-trifluoromethylphenyl)pyridazin-3(2//)-one 169, has been successfully tackled (Equation 27) <2005JHC427>. In this case, the use of a tri(2-furyl)phosphine rather than a triphenylphosphine-based palladium catalyst was essential to achieve high yields. 

Catalytic hydrogenation of (23-12) over palladium on charcoal results in the scission of the weak N—O bond and the formation of amino alcohol (24-1). This is converted to a pyrrolidine by an internal alkylation reaction. Thus, reaction of the intermediate with carbon tetrabromide and triphenyl phosphine presumably converts the alcohol to a bromide internal displacement by the primary amine forms the five-membered ring (24-2). Alkylation of that amine with the complex bromo amide (24-3) then affords the endothehn antagonist atrasentan (24-4) [25]. 

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