Halides, aryl, with active microwaves

Aryl triflates were shown to react directly with secondary amines in A -methylpyr-rolidine solvent using microwave irradiation. Activated halides can be converted to diethylamino compounds ArX ArNMc2 by treatment with HMPA. Anihne derivatives react with activated aromatic rings, in the presence of tetrabutylammo-... 

A more recent publication by Weigand and Pelka has disclosed a polymer-bound Buchwald-Hartwig amination [40], Activated, electron-deficient aryl halides were coupled with conventional PS Rink resin under microwave irradiation. Subsequent acidic cleavage afforded the desired aryl amines in moderate to good yields (Scheme 7.22). Commercially available Fmoc-protected Rink amide resin was suspended in 20% piperidine/N,N-dimethylformamide at room temperature for 30 min to achieve deprotection. After washing and drying, the resin was placed in a silylated microwave vessel and suspended in dimethoxyethane (DME)/tert-butanol... 

In a related study, Srivastava and Collibee employed polymer-supported triphenyl-phosphine in palladium-catalyzed cyanations [142]. Commercially available resin-bound triphenylphosphine was admixed with palladium(II) acetate in N,N-dimethyl-formamide in order to generate the heterogeneous catalytic system. The mixture was stirred for 2 h under nitrogen atmosphere in a sealed microwave reaction vessel, to achieve complete formation of the active palladium-phosphine complex. The septum was then removed and equimolar amounts of zinc(II) cyanide and the requisite aryl halide were added. After purging with nitrogen and resealing, the vessel was transferred to the microwave reactor and irradiated at 140 °C for 30-50 min... 

A new method of synthesis of A-alkylphthalimides (79) via alkylation of phthalim-ide in dry media under microwave irradiation was carried out by Bodgal et al. (1996). The reactions were performed by simply mixing phthalimide with an alkyl halide adsorbed on potassium carbonate to give a good yield of the product. Yadav and Subba Reddy (2000) reported a novel and efficient synthesis of A-arylamines (80) by the reaction of activated aryl halides with secondary amines in the presence of... 

Aryl halides are converted to phenols if activating groups are present or if exceedingly strenuous conditions are employed. When the reaction is carried out at high temperatures, cine substitution is observed, indicating a benzyne mechanism. The reaction has been done using NaOH on Montmorillonite KIO and AgNOa with microwave irradiation. ... 

The reaction between aryl halides and cuprous cyanide is called the Rosenmund-von Braun reaction Reactivity is in the order I > Br > Cl > F, indicating that the SNAr mechanism does not apply. Other cyanides (e.g., KCN and NaCN) do not react with aryl halides, even activated ones. This reaction has been done in ionic liquids using CuCN. ° The reaction has also been done in water using CuCN, a phase transfer catalyst, and microwave irradiation. 

Fluoride-free Hiyama cross-coupling reactions of phenyltrimethoxysilane with aryl halides was performed in water using sodium hydroxide as activator at 110°C under microwave heating [32]. The reaction was catalyzed by poly (N-viityl-2-pyrrolidone) (PVP)-stabilized colloidal palladium NPs. The reaction proceeds quickly under microwave heating (6 min). 

The N-aiylindole subunit is an important species in many biologically active and pharmaceutically important compounds, which display antiestrogen, analgesic, antiallergic, antinticrobial and neuroleptic activity. Xu and Fan (2008) carried out nticrowave-assisted nucleophilic aromatic substitution reaction of indoles with fluo-ro- and chloro-substituted aryl halides to synthesize N-arylindoles via C(sp )-N(sp ) bond formation in the presence of K2CO3 or Cs COj under microwave irradiation (420 W). Reaction was completed within 25-40 min with good yields (46-94%). 

An efficient Stille cross-coupling reaction catalyzed by ortho-palladated complex of tribenzylamine was carried out by Hajipour et al. (2012) under microwave irradiation. The catalytic activity of [Pd CgH2N(CH2Ph)2) (m-Br)]2 complex as an efficient and stable catalyst (nonsensitive to air and moisture) in Stille cross-coupling reaction of various aryl halides with phenyltributyltin under microwave irradiation was investigated. The substituted biaryl halides were produced in excellent yields in short reaction times using a catalytic amount of this complex at 100°C. 

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