Chlorobenzene complexes

Treatment of the labile chlorobenzene complex [Re(ClPh)(NO)(PPh3)Cp ]BF4 with HC=CC CSiMe3 gave two inseparable rotamers of [Re( ) -HC2C=CSiMe3) (NO)(PPh3)Cp ]BF4. ... 

Fig. 6. Molar percentages of aromatic compounds in a typical reaction mixture at 120°C with reactants H,PtCI and benzene in water-trifluoroacetic acid solution ( ) benzene ( ) benzene complex (A) chlorobenzene complex (O) chlorobenzene ( ) total. [Reproduced from Sanders el al. (84).]...

Intermolecular Nucleophilic Substitution with Heteroatom Nucleophiles. A patent issued in 1965 claims substitution for fluoride on fluorobenzene-Cr(CO)3 in dimethyl sulfoxide (DMSO) by a long list of nucleophiles including alkoxides (from simple alcohols, cholesterol, ethylene glycol, pinacol, and dihydroxyacetone), carboxylates, amines, and carbanions (from triphenyhnethane, indene, cyclohexanone, acetone, cyclopentadiene, phenylacetylene, acetic acid, and propiolic acid). In the reaction of methoxide with halobenzene-Cr(CO)3, the fluorobenzene complex is ca. 2000 times more reactive than the chlorobenzene complex. The difference is taken as evidence for a rate-limiting attack on the arene ligand followed by fast loss of halide the concentration of the cyclohexadienyl anion complex does not build up. In the reaction of fluorobenzene-Cr(CO)3 with amine nucleophiles, the coordinated aniline product appears rapidly at 25 °C, and a carefiil mechanistic study suggests that the loss of halide is now rate limiting. 

The SjvAr reaction is another attractive method for diaryl ether synthesis, and reactions of o-nitro- and o-cyanofluorobenzenes with phenols were reported . 7r-Complexation of aryl halides with transition metals activates the aromatic nuclei toward S fAr. Segal employed a ruthenium chlorobenzene complex in the poly(aryl ether) synthesis , and the methodology was extensively studied by Pearson, Rich and their coworkers using manganese complex and later iron and ruthenium complexes in natural product synthesis " . The intramolecular substitution of an aromatic chloride with a phenylalanine derivative takes place at room temperature without racemization (equation 27). 

Ph2P(CH2)3CgH5 ] in chlorobenzene at 130°C and, in higher yield, by exhaustive anodic oxidation and subsequent spontaneous in situ reduction of the presumed labile ruthenium(iii) species. However, we have consistently been unable to reproduce the thermal reaction, either under the stated conditions or in CH2Cl2/thf at 120°C. In refluxing chlorobenzene the p-cymene is displaced and we have obtained NMR spectroscopic evidence for the formation of a chlorobenzene complex, but attempts to isolate it failed. 

While arenetricarbonylchromium complexes are deactivated to electrophilic substitution with respect to the free arene, their susceptibility to nucleophilic substitution is enhanced. The chlorobenzene complex, for example, undergoes ready substitution by sodium methoxide. In this way it resembles l-chloro-4-nitrobenzene. 

In some cases, however, products corresponding to other addition pathways can be isolated. The chlorobenzene complex 42 reacts with a nucleophile prepared from 3-ethoxy-6-methylpyridazine-l-oxide to give the product from a addition... 

Chlorobenzene reacts with alkenes with bimetallic catalyses of Ni and Pd. Chlorobenzene is converted in situ into iodobenzene (14) by the Ni-cataiyzed reaction of Nal at 140 "C. NiBr2, rather than the Ni(0) complex, is found to be a good catalyst. Then the Pd-catalyzed reaction of the iodobenzene with acrylate takes place) 15]. 

BenZotrichloride Method. The central carbon atom of the dye is supphed by the trichloromethyl group from iJ-chlorobenzotrichloride. Both symmetrical and unsymmetrical triphenyhnethane dyes suitable for acryhc fibers are prepared by this method. 4-Chlorobenzotrichloride is condensed with excess chlorobenzene in the presence of a Lewis acid such as aluminium chloride to produce the intermediate aluminium chloride complex of 4,4, 4"-trichlorotriphenylmethyl chloride (18). Stepwise nucleophihc substitution of the chlorine atoms of this intermediate is achieved by successive reactions with different arylamines to give both symmetrical (51) and unsymmetrical dyes (52), eg, N-(2-chlorophenyl)-4-[(4-chlorophenyl) [4-[(3-methylphenyl)imino]-2,5-cyclohexadien-l-yhdene]methyl]benzenaminemonohydrochloride [85356-86-1J (19) from. w-toluidine and o-chloroaniline. 

All of the chlorobenzenes are now produced by chlorination of benzene in the Hquid phase. Ferric chloride is the most common catalyst. Although precautions are taken to keep water out of the system, it is possible that the FeCl3H20 complex catalyst is present in most operations owing to traces of moisture in benzene entering the reactor. This FeCl3H20 complex is probably the most effective catalyst (13). 

Wilkes and co-workers have investigated the chlorination of benzene in both acidic and basic chloroaluminate(III) ionic liquids [66]. In the acidic ionic liquid [EMIM]C1/A1C13 (X(A1C13) > 0.5), the chlorination reaction initially gave chlorobenzene, which in turn reacted with a second molecule of chlorine to give dichlorobenzenes. In the basic ionic liquid, the reaction was more complex. In addition to the... 

The selective insertion of diphenylacetylene in the cyciopaiiadated sulfide complex 1 leads to the stable organometallic complex 2, which can be depalladated with silver(I) tetrafluoroborate to give a mixture of the dibenzothiepinium salt 3 and the dibenzo[Z>,z ]thiepin 4.91 Demethyla-tion of 3 to yield 4 is complete after refluxing overnight in chlorobenzene. The synthetic scope of this method for thiepin derivatives is limited due to their thermal instability, but the method is very suitable for the synthesis of 1//-2-benzothiopyrans.91... 

Hatada et have indicated that PVAc prepared in aromatic solvents (benzene, chlorobenzene) at 60 °C has fewer branch points than the polymer prepared in ethyl acetate under similar conditions. They attributed this observation to complexation of the propagating radical in the aromatic solvents and the... 

More than twenty years ago, Nesmeyanov s group showed that chlorine can be substituted by a variety of nucleophiles in FeCp(r 6-PhCl)+ [83, 84]. Indeed the chlorine substituent in the chlorobenzene (even) ligand is 1000 times more reactive than when it is located on the cyclopentadienyl (odd) ligand [85]. The FeCp+ is a good withdrawing group which is equivalent to two nitro groups in terms of activation. The reactions proceed under ambient conditions with primary or secondary amines and have been extended to other substituted chloroarene complexes [86, 87] Eq. (22), Table 2. 

Protonation of the TMM complexes with [PhNMe2H][B(C6Fs)4] in chlorobenzene at —10 °C provided cationic methallyl complexes which are thermally robust in solution at elevated temperatures as determined by NMR spectroscopy. In contrast, addition of BfCgFsls to the neutral TMM precursors provided zwitterionic allyl complexes (Scheme 98). Surprisingly, it was found that neither the cationic nor the zwitterionic complexes are active initiators for the Ziegler-Natta polymerization of ethylene and a-olefins. °°... 

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