Phase-transfer catalysis nucleophilic aromatic

Interests in the phase transfer catalysis (PTC) have grown steadily for the past several years [68-70]. The use of PTC has recently received industrial importance in cases where the alternative use of polar aprotic solvents would be prohibitively expensive [71-74]. Thus, the potential application of the phase transfer catalyzed aromatic nucleophilic displacement reactions between phenoxide or thiophenoxide and activated systems has... 

There has been a useful review of phase-transfer catalysis in nucleophilic aromatic substimtion. A comparison has been reported of the reactions with nucleophiles of l-chloro-2,4-dinitrobenzene (substimtion) and 4-nitrophenyl diphenyl phosphate (dephosphorylation) in neutral micelles of dodecyl (10) and (23) polyoxyethylene glycol. In the substimtion reaction considerable amounts of ether may be formed by reaction with alkoxide ions at the micellar surface. Differences in reactivity of the two substrates are probably due to differences in their location in the micellar structures. ... 

Perchloro-organic chemistry structure, spectroscopy and reaction pathways, 25, 267 Permutational isomerization of pentavalent phosphorus compounds, 9, 25 Phase-transfer catalysis by quaternary ammonium salts, 15, 267 Phosphate esters, mechanism and catalysis of nucleophilic substitution in, 25, 99 Phosphorus compounds, pentavalent, turnstile rearrangement and pseudorotation in permutational isomerization, 9, 25 Photochemistry of aryl halides and related compounds, 20, 191 Photochemistry of carbonium ions, 9, 129 Photosubstitution, nucleophilic aromatic, 11, 225... 

The first comprehensive study applying phase transfer catalysis to aromatic nucleophilic substitution appeared in 1974 and deals with carbanion nucleophiles derived from phenylalkanenitriles. The catalyst is triethylbenzylammonium chloride (TEBA).39 ... 

BTF is a suitable solvent for conducting heterogeneous reactions with phase transfer catalysis. The reaction of benzyl chloride with sodium cyanide (in toluene and BTF) or potassium cyanide (in acetonitrile and BTF) using two different phase transfer catalysts [70] gave similar yields (12.1 12.2). Aromatic nucleophilic substitution of chloro-2,4-dinitro benzene using potassium fluoride and... 

Synthesis of aromatic ethers has been performed under solvent-free phase-transfer catalysis conditions by reaction of several aryl halides with potassium methoxide or phenoxide in the presence of a catalytic amount of 18-crown-6. The specific MW effects were shown to be very dependent on the nucleophile and on the structure of the aromatic compound (activated or nonactivated, chloride or fluoride) (Eq. (56), Table 4.17) [96, 142]. 

Nucleophilic Substitutions. 7V,7V-Dimethyldithiocarbamoyl-acetonitrile (1) serves as an active methylene compound, because its carbanion is stabilized by sulfur and cyano groups. It can be alkylated stepwise in aqueous sodium hydroxide under phase transfer catalysis (eq 1). The anion undergoes nucleophilic aromatic substitution to give nitroarenes, with elimination of the dithiocarbamate group (eq 2). Nucleophilic addition of (1) to phenyl isothiocyanate also occurs readily. ... 

Solid-liquid phase transfer catalyst 2 for aliphatic and aromatic nucleophilic substitution synergistic effect with Cu in Ullmann synthesis as ligand in homogeneous hydrogenation catalysis (see 1st edition). 

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