With aryl halides groups

When allene derivatives are treated with aryl halides in the presence of Pd(0), the aryl group is introduced to the central carbon by insertion of one of the allenic bonds to form the 7r-allylpalladium intermediate 271, which is attacked further by amine to give the allylic amine 272. A good ligand for the reaction is dppe[182]. Intramolecular reaction of the 7-aminoallene 273 affords the pyrrolidine derivative 274[183]. 

The group of Ley has reported on the use of palladium-doped perovskites as recyclable and reusable catalysts for Suzuki couplings [151]. Microwave-mediated cross-couplings of phenylboronic acid with aryl halides were achieved within 1 h by utilizing the supported catalyst (0.25 mol% palladium) in aqueous 2-propanol (Scheme 7.127). The addition of water was crucial as attempted transformations in non-aqueous mixtures did not proceed. 

The regioselective arylation occurs when the reaction of 2-arylpyridines with aryl halides is conducted with the aid of the ruthenium(ii)-phosphine complex as catalyst (Equation (66)).81 The ortho-position to the 2-pyridyl group is arylated predominantly. The aromatic imines are also arylated with the same catalytic system.82... 

Ishikura and co-workers have done extensive work on the utility of indolylborates such as lithium triethyl(l-methylindol-2-yl)borate (136), prepared as shown from 1-methylindole, in Suzuki-like Pd-catalyzed reactions [147-157]. For example, 136 couples smoothly with aryl halides to afford 2-arylindoles 137 [147]. The amount of 2-ethyl-1-methylindole by-product, formed by ethyl group migration, can be minimized by refluxing the mixture. At room temperature 2-ethyl-1-methylindole is the major product. More recent work by Ishikura extended these couplings to the (removable) A-Boc analog of 136 with comparable yields to those obtained with 136 [157]. 

Ohta s group investigated the heteroaryl Heck reaction of thiophenes and benzothiophenes with aryl halides [127] and chloropyrazines [128]. Addition of the electrophiles invariably took place at C(2) as exemplified by the formation of arylbenzothiophene 156 from the reaction of benzothiophene and p-bromobenzaldehyde [127]. As expected, the heteroaryl Heck reaction of 2-thienylnitrile, an activated thiophene, with iodobenzene afforded the arylation product 157 [129],... 

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... 

The first report of resin capture in solution-phase chemical library synthesis involved the covalent capture of solution-phase Ugi reaction products onto a functionalized polystyrene resin.73 Excess reactants, reagents, and reagent byproducts were washed away from the resin-captured intermediates. Further manipulation and release afforded purified solution-phase products for screening. More recently the same group reported on resin capture as a technique for the preparation of tetrasubstituted olefin libraries.74 75 As illustrated in Scheme 5, m-vinyl di-boryl esters were reacted with aryl halides (R3ArX) in parallel Suzuki reactions, leading to solution-phase intermediates. Another Suzuki reaction, this time with the... 

Displacement reactions with nitrite ion do not work well with aryl halides. However, displacement of the diazonium group is a practical route to nitroarenes (the Sandmeyer reaction), as described in Section 23-10B ... 

The reaction is used chiefly with alkyl halides, although when certain acidic groups are present in the nucleus in the o- or p-position to the halogen, the reaction gives satisfactory results with aryl halides. 

Vinyl substitution of primary or secondary allylic alcohols with aryl halides usually produces 3-aryl aldehydes or ketones, respectively. The reaction is believed to involve an addition of the intermediate arylpalladium halide to die double bond, placing the aryl group mainly on the more distant carbon from the hydroxy group, followed by palladium hydride elimination, a reverse readdition and another elimination with a hydrogen atom on the carbon bearing the hydroxy group. The product is probably a ir-com-plex of the enol which ultimately either dissociates or collapses to a a-complex with palladium on the... 

Nucleophilic substitution reactions can occur with aryl halides, provided that strong electron-withdrawing groups (deactivators) are located ortho and/or para to the carbon atom that s attached to the halogen. (This arrangement makes the carbon susceptible to nucleophilic attack.)... 

During arylations of carbon nucleophiles with aryl halides in the presence of palladium triarylphosphine complexes products containing the aryl group of the phosphine can result (Scheme8.16). These reactions proceed via reversible arylation of the Pd-bound phosphine, which occurs at temperatures above 50 °C, particularly readily in the presence of iodide [11] (see Section 8.2). Electron-deficient aryl groups usually migrate less readily than electron-rich groups [23, 25],... 

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