With aryl halides, and the

The reactions between i-dinitrobenzene or 1,3,5-trinitrobenzene, aryl halides, and copper(I) oxide in quinoline 17-19, 21) provide a simple synthesis of nitrobiphenyls uncontaminated by symmetrical biphenyls. These couplings may be related to the Ullmann reaction, the decarboxylative coupling of benzoic acids with aryl halides, and the preparation of ethers from phenols 165). Although no intermediates... 

Other methods to reduce polycyclic quinones to arenes that have met with some success include SnCU/HCl, 58 Zn/NH3, 59Zn/pyridine/MeC02H, NaBH4/BF3-Et20, 6 and NaBH4 in MeOH. All of these methods are compatible with aryl halides and the latter two are also compatible with aryl ethers, anilines and phenols. lO-Arylmethylene-9-anthrones have also been reduced to anthracenes with dibo-rane (Scheme 75). ... 

Diaryl ketones. V-Pyrazylaldimines couple with aryl halides and the products are readily hydrolyzed to the ketones. 

In the reaction of Q,/3-unsaturated ketones and esters, sometimes simple Michael-type addition (insertion and hydrogenolysis, or hydroarylation, and hydroalkenylation) of alkenes is observed[53,54]. For example, a simple addition product 56 to methyl vinyl ketone was obtained by the reaction of the heteroaromatic iodide 55[S5]. The corresponding bromide affords the usual insertion-elimination product. Saturated ketones are obtained cleanly by hydroarylation of o,/3l-unsaturated ketones with aryl halides in the presence of sodium formate, which hydrogenolyses the R—Pd—I intermediate to R— Pd—H[56]. Intramolecular hydroarylation is a useful reaction. The diiodide 57 reacts smoothly with sodium formate to give a model compound for the afla-toxin 58. (see Section 1.1.6)[57]. Use of triethylammonium formate and BU4NCI gives better results. 

Harrwig and Bnchwidd have developed a new methodology for aryladon of amines or phenols with aryl halides and palladium catiilysts This reacdon provides a very useful strategy for the preparadon of various heterocyclic compounds such as phenazines, as shown in Scheme... 

How- does this reaction take place Although it appears superficially similar to the SN1 and S 2 nucleophilic substitution reactions of alkyl halides discussed in Chapter 11, it must be different because aryl halides are inert to both SN1 and Sj 2 conditions. S l reactions don t occur wdth aryl halides because dissociation of the halide is energetically unfavorable due to tire instability of the potential aryl cation product. S]sj2 reactions don t occur with aryl halides because the halo-substituted carbon of the aromatic ring is sterically shielded from backside approach. For a nucleophile to react with an aryl halide, it would have to approach directly through the aromatic ring and invert the stereochemistry of the aromatic ring carbon—a geometric impossibility. 

This reaction is similar to 13-1 and, like that one, generally requires activated substrates. With unactivated substrates, side reactions predominate, though aryl methyl ethers have been prepared from unactivated chlorides by treatment with MeO in HMPA. This reaction gives better yields than 13-1 and is used more often. A good solvent is liquid ammonia. The compound NaOMe reacted with o- and p-fluoronitrobenzenes 10 times faster in NH3 at — 70°C than in MeOH. Phase-transfer catalysis has also been used. The reaction of 4-iodotoluene and 3,4-dimethylphenol, in the presence of a copper catalyst and cesium carbonate, gave the diaryl ether (Ar—O—Ar ). Alcohols were coupled with aryl halides in the presence of palladium catalysts to give the Ar—O—R ether. Nickel catalysts have also been used. ... 

A useful new method of preparing arylphosphonates (123) involves the reaction of trialkyl phosphites with aryl halides in the presence of a nickel catalyst.The suggested mechanism is via the nickel complex (124), and is non-radical. 

We have found that palladacycles 2 and 5 also react with aryl halides but the reaction pathway follows a different course in the absence (complex 2) or in... 

Palladium-catalyzed hydroarylation of sterically hindered PTAD adduct 157 with aryl halides in the presence of triphenylarsine, sodium acetate, and DMSO provides a 1 1 mixture of 170 and 171. The same reaction done with sodium fluoride and formic acid provides mixtures containing 171 as the major product. Apparently, the use of sodium fluoride as a base allows the selective formation of the opening products 171 in good yields (Equation 19). Similarly, the 2,3-phthalazine-l,4-dione adduct 172 provides the corresponding products 173 and 174 (Equation 20) <2002AGE3375>. 

The intermolecular coupling of lactams and acyclic amides has also been reported. Reactions of carbamates with aryl halides occurred in the presence of catalysts ligated by P(/-Bu)3.78 Both carbamates and amides coupled with aryl halides in the presence of a catalyst bearing Xantphos.90 In addition, the coupling of lactams with aryl halides has been successful. A combination of Pd(OAc)2 and DPPF first formed A-aryl lactams in good yields from 7-lactams, but the arylation of amides was improved significantly by the use of Xantphos (Equations (20) and (21)).90 91 The reaction of aryl halides with vinyligous amides has also been reported 92... 

In addition, the reactions of dialkoxyboranes, such as pinacolborane, with aryl halides and base have been reported.182,183 The yields are lower for reactions of this reagent in some cases than they are for reactions of the diboron reagent, but good yields are obtained from aryl bromides in most cases. Dialkoxyboranes are less expensive than the analogous diboron compounds, but the diboron compound is very stable thermally and is stable in air. 

The palladium-catalyzed arylations of aromatic carbonyl compounds such as ketones,67,67a amides (Equation (60)),68 and aldehydes69 with aryl halides and triflates give the multiple arylation products similarly. 

A recent report has shown that tricyclopropylbismuth can be utilized in the cross-coupling reaction with aryl halides and triflates [57]. Representative examples are shown in Scheme 38. Addition of a base activator and excess of the bismuth reagents are necessary to obtain the coupling products in good yields, although more than one cyclopropyl group was transferred when 0.5 equivalents of... 

Mowery and DeShong reported on the use of siloxanes 72 (Figure 16) as versatile transmetallation agents for Pd(dba)3-catalyzed couplings with aryl halides and allylic alcohol derivates, in the presence of TBAF and at high temperature (95 They later used aryl silatrane 73 (Figure 16) as a suitable partner for the fluoride-promoted... 

Aryl ketones can also be prepared by C-acylation of support-bound arylstannanes with acyl halides (Entry 4, Table 12.1). The reaction conditions are mild and suitable for selective chemical transformations of polystyrene-bound intermediates. As an alternative, resin-bound arylstannanes can be converted into benzophenones by treatment with aryl halides and carbon monoxide ([(Pd(PPh3)4], DMSO, 80 °C, 18 h-3 d [8]). 

The report by Bunnett and coworkers107 of substitution of halide by MeCOCth" or PhS- ions in vinyl bromides or iodides appears to be the only synthetic application of the SrnI reaction at vinylic sites. The reactions, particularly with benzenethiolate ion, are slower than those of aryl halides and the yields are not as good. Tautomers or mixtures of products result in the reactions with MeCOCH2 (e.g. equation 32). 

Recently, Taillefer et al. reported an Fe/Cu cooperative catalysis in the assembly of N-aryl heterocycles by C—N bond formation [90]. Similarly, Wakharkar and coworkers described the N-arylation of various amines with aryl halides in the presence of Cu—Fe hydrotalcite [91]. Interestingly, Correa and Bolm developed a novel and promising ligand-assisted iron-catalyzed N-arylation of nitrogen nucleophiles without any Cu co-catalysts (Scheme 6.19) [92]. Differently substituted aryl iodides and bromides react with various amides and N-heterocycles. The new catalyst system consists of a mixture of inexpensive FeCl3 and N,N -dimethylethylenediamine (dmeda). Clearly, this research established a useful starting point for numerous future applications of iron-catalyzed arylation reactions. 

The Miyaura borylation reaction enables the synthesis of boronates by cross-coupling of bis(pinacolato)diboron (B2pin2) with aryl halides and vinyl halides. 

Pivsa-Art, S. Satoh, T. Kawamura, Y. Miura, M. Nomura, M. Palladium-catalyzed arylation of azole compounds with aryl halides in the presence of alkali metal carbonates and the use of Cul in the reaction. Bull. Chem. Soc. 

Kappe and Stadler have invented a microwave protocol enabling quick access to triaryl phosphines via coupling of diphenylphosphine with aryl halides and triflates [107]. Because of the value of phosphine ligands in assorted transition metal-catalyzed reactions, convenient routes for their pro-... 

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