Aryloxide anions

Alkoxide or aryloxide anions are also reputed to be inactive in Sr I reactions. There is, however, one example of such a reaction at an sp carbon the nitro-derivative of 4-nitrocumyl reacts with phenoxide and 1-methyl-2-naphthoxide ions yielding the corresponding ethers (Kornblum et al., 1967). A similar reaction has been reported for halobenzenes in t-butyl alcohol upon stimulation by sodium amalgam (Rajan and Sridaran, 1977). This reaction could not, however, be reproduced (Rossi and Pierini, 1980) and other attempts to make phenoxide ions react at sp carbons have been equally unsuccessful (Ciminale et al, 1978 Rossi and Bunnett, 1973 Semmelhack and Bargar, 1980). It has been found, more recently, that phenoxide ions react with a series of aryl halides under electrochemical induction, but that the coupling occurs at the p- or o-phenolic carbon rather than at the phenolic oxygen (Alam et al, 1988 Amatore et al, 1988). This is... 

For diastereoisomeric 2-chloro-4-isopropyl-5,5-dimethyl-1,3,2x -dioxaphosphorinanes, the displacement of chlorine by aryloxide anions proceeds readily complete inversion was observed with the weakest nucleophile examined,viz., 4-nitro-phenoxide, a feature already recorded for less substituted 1,3,2-dioxaphosphorinanes, and a comparison of the inversion, or retention (as observed with other nucleophiles) ratios with those for other cyclic phosphorus(V) chlorides in the same series suggests that the 4-isopropyl group exerts an appreciable steric control on the stereochemistry of the displacement process. 

Free alkoxide and aryloxide anions are Bronsted bases with pK values of the corresponding alcohols ranging from 5 to 20 in water. The basicity is highly dependent on the electronic properties of the alkyl or aryl moieties. For example, the pK value of hexafluoro-tert-butanol, (CF3)jMeCOH, is 9.6, which is considerably lower than the pK value of tert-butanol (19.2), but roughly the same as that of phenol (9.9). Such differences in electronic, as well as steric, environments often leads to the different structures and reactivity patterns for compounds containing similar ancillary ligands, but different alkoxides or aryloxides. 

In an unusual reaction, anhydrous [LnCb] (Ln = Nd or Er) was reacted with [NaOCeH3Ph2-2,6] in 1,3,5-tri-im-butylbenzene at 300°C to generate [NaLn(OAr)4] which reacts with DME to form the discrete tetra-aryloxide anions. ... 

For example, reacting the 4-isomer with sodium phenoxide at room temperature produced ring-opening mixtures of ester acids. This not only resulted in consumption of aryloxide anions but simultaneously generated materials which were not susceptible to nitro-displacement. 

Figure 12.7 Ruthenium complexes with increased rigidity of the chelate ring (31, 32), and fluoro aryloxide anionic ligands (33-35).

Oxygen-Gontaining Organics. Neutral and anionic oxygen-containing organic molecules form complexes with thorium. Recent work has focused on alkoxides (72), aryloxides, and carboxylates however, complexes with alcohols, ethers, esters, ketones, aldehydes, ketoenolates, and carbamates are also well known. 

In some cases the problem is relatively simple. For example the binding of organic, nucleophilic anions, e.g. aryloxides or areneimidazolide anions, can be estimated from the spectral shifts which occur when the ion is transferred from water to micelles (Sepulveda, 1974 Bunton and Sepulveda, 1979 ... 

The six high spin Fe sites in the [(Fe6S5X5)(M(CO)3)2]" anions are antiferromagnetically coupled as evidenced by the reduced ambient temperature magnetic moments, and the temperature dependence of the isotropically shifted resonances in the aryloxide derivatives. 

Acid catalyzed Sehiff base condensation of 2,6-diformyl-p-cresol and TETA (triethylenetetraamine) with Pr3+ as the template cation (in methanol) afforded a 1 1 product containing a tetraclinching alcohol (Eq. 9b, Table 9) [132]. One of the carbonyl groups was acetylated under mild acidic conditions. The 10-coord-ination around Pr3 + achieved by one aryloxide site, one imine and three amino nitrogen, two bidentate nitrate anions and one molecule of methanol is best described as a bicapped square antiprism. 

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