Phenyl bromide iodide

The resting state of this catalytic system was found to be the dimer shown. The migratory insertion is the rate-determining step and not the oxidative addition of aryl halide to a palladium zero species, see Figure 13.17. These kinetics were found for phenyl iodide phenyl bromide already showed less clear-cut kinetics indicating that the oxidative addition is somewhat slower now. The system shown in Figures 13.16-17 gives at least half a million turnovers. 

The dichloride reacts with magnesium phenyl bromide, CeHs.MgBr, in ether solution, with formation of diphenyl telluride, (C6H5)2Te. Tellurium dibromide and di-iodide give a similar result.8 In ether solution the dichloride absorbs bromine and iodine, but the products, presumably the chlorobromide and chloro-iodide, respectively, have not been isolated.9... 

Benzaldehyde and magnesium phenyl bromide or iodide give diphenyl carbinol. 

The possibility of preparing aryl tellurium halides from equimolar amounts of diaryl ditellurium compounds and aryl tellurium trihalides has hardly been explored. Only phenyl tellurium iodide and 2-biphenylyl tellurium bromide could be obtained by this route. The other aryl tellurium halides (including 3,4-dimethoxyphenyl tellurium chloride) decomposed under the reaction conditions to give diaryl tellurium dihalides and tellurium5. 

Treatment of the 1 1 complexes between phenyl tellurium bromide and ethylenethio- or -selenourea with sodium iodide in warm methanol yielded the corresponding phenyl tellurium iodide complexes5. 

The following compounds were obtained from phenyl tellurium iodide or 4-methoxyphenyl tellurium bromide and organic lithium compounds ... 

Unlike alkyl halides, phenyl bromide and iodide reacted only sluggishly with diaryl telluriums. The neat reagents had to be heated at 150° for 40 h to obtain moderate yields of triaryl telluronium halides3. 

Mercury diphenyl has been prepared in a number of ways. The most important methods are by the action of sodium on a mixture of bromobcnzene and mercuric chloride 1 from sodium amalgam and phenyl mercuric iodide 2 by the interaction of phenyl mercuric bromide and potassium sulfide2 or phenyl mercuric acetate and sodium stannite 3 from phenyl magnesium bromide and mercuric chloride 4 by the action of phenyl hydrazine on mercury compounds 5 from mercuric chloride and phenyl arsenious oxide 6 and from diphenyl mercuric ammonium acetate and sulfur compounds.7... 

Two methodologies for the direct C-2 arylation of thiazoles have been reported. The first one is mediated by both palladium and copper <07T1970>. Thus, the C-2 arylation of thiazole and benzothiazole with aryl iodides is carried out using copper iodide (2 equiv.) and a catalytic amount of palladium acetate under base-free conditions. The other method involves copper-catalyzed arylation with aryl iodides in the presence of lithium t-butoxide <07JA12404>. In general, reactions with lithium tert-butoxide provide better yields than those with potassium fert-butoxide. In addition, arylation with phenyl bromide, chloride or tosylate fails to provide any desired arylation products. 

In cyclohexadienylidene 3g however the stereospecifity in the addition to cfs-butene is lost with increasing concentrations of hexafluorobenzene 68D). The ratio of cfs-adduct/ fflMS-adduct drops from 18.0, 4.5 to 2.0 as the mole % of CeFe is increased from 0, 74 to 90%. Solvents with heavy atoms such as methyl-iodide or phenyl-bromide favor also S T conversions in the case of 3g 68b) ... 

Cuprous phenyl, CuPhU—Cuprous iodide is added to a cold solution of magnesium phenyl bromide in ether. Complete solution takes place, and after a time the cuprous phenyl separates out as a white powder. It decomposes at 80° C. and when warmed with benzene is converted quantitatively into diphenyl and metallic copper, the latter appearing as a mirror. With water, benzene and cuprous oxide are formed, and with dilute nitric acid it is changed to nitrobenzene, concentrated nitric acid causing the compound to explode. Cuprous phenyl blackens in a few days, even when kept in a vacuum. 

The interaction of trimethyl boric ester and magnesium metliyi iodide in ether, followed by decomjiosition with acidified water, yields methyl boric acid, as white crystals, very volatile and unstable. It has never been isolated in the pure state, but Michaelis and Becker showed that it exerts a methylating action on magnesium phenyl bromide, the products consisting of phenyl boric acid and toluene. The esters of this acid are readily hydrolysed by cold water. 

Chloromercuriphenyl-a-amino) propionic ethyl ester, 127. 2-Chloromercuriphenylglyoine ethyl ester, bromide, iodide, 127. 5-Chloromerouri-2-phenyl thiophene, 99. 

Metallations of allyl sulfoxides have been achieved at -78 C with n-butyllithium in THP or more efficiently with LDA under similar conditions. - - Alkylations with primary alkyl iodides - - - and allylations with allyl - or phenyl bromides proceed in good yield, usually below -20 C and in less than 6 h. The reaction takes place predominantly at the a-site but there is often competition from y-alkylation leading to a-alkenyl sulfoxides (Scheme 98 Scheme 99). Changing the solvent, or introducing metal ion complexing agents, such as TMEDA were unsuccessful in changing the a y ratios observed in THF. 

Similarly, for reactions of 2-(3-butenyl)phenyl bromide and iodide. D-model equation (7.31) predicts 78% cyclized Grignard reagent and 22% uncyclized. Much less eyeli/ation is observed. 

Even qualitatively, the results for reactions in THF, especially, are striking. In this system, the rate constant for the eyelization of R is a thousand times that for 5-hexenyl halides, where 3-10% eyelization occurs. Despite this, from 2-(3-bu-tenyl)phenyl bromide and iodide in THF, >98% yields of RMgX are obtained, with <1.5% QMgX [1121. This seems inconsistent with a dominant pathway R of any kind. 

Dipole cycloaddition of diazomethane to 2-bromo-3,3,3-trifluoropropene 48 (Scheme 12.6) followed by dehydrobromination affords 41, quantitatively. A copper-catalyzed A-phenylation reaction of 41 with phenyl bromide or iodide under mild conditions provides A-phenyl-3-trifluoromethylpyrazole 47 in excellent yields. 

Under electrochemical reduction conditions, 2-propenyl bromide reacts with benzaldehyde in the presence of a catalytic amount of CrCl2 and Pd(OAc)2 and provides a-isopropenylbenzyl alcohols in moderate yield (Scheme 48). Phenyl bromide and iodide show similar reactivity and provide benzhydrol derivatives in comparable yield. 

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