Li salts

PdCb, and the allylated lactone 232 is formed. Regeneration ofPdCl2 as shown by 231 makes the reaction catalytic. In this reaction, use of the Li salt 227 of 4-pentynoic acid (223) is recommended. Reaction of lithium 3-octynoate (233) with allyl chloride affords the unsaturated lactone 234, which is converted into the 7-keto acid 235 by hydrolysis[126]. 

Fig. 3. Pseudocyclic structure of 12-Li+ salt on the basis of the CPK model. (Cited from Ref.I7>)...

The Li salt Li2[Ga2Brg] can be obtained" from LiBr and GaBrj at 250°C. 

N-silylated imines 509 react with the Li salts of tosylmethylisonitriles to give 4,5-disubstituted imidazoles in moderate yields [93]. Acetylation of N-trimethylsilyl imines 509 with acetyl chloride and triethylamine affords 72-80% of the aza-dienes 510 these undergo readily Diels-Alder reactions, e.g. with maleic anhydride at 24 °C to give 511 [94] or with dimethyl acetylenedicarboxylate to give dimethyl pyridine-3,4-dicarboxylates [94] (Scheme 5.29). 

The product is 2,7-octadien-l-oI which can be dehydrogenated/hydrogenated internally to give 7-octenal, which can be hydroformylated to the dialdehyde, nonadialdehyde, and then hydrogenated to nonadiol. The initial product can be hydrogenated to 1-octanol the dialdehyde can be oxidized to the diacid. The catalyst used is Pd modified with the Li salt of monosulphonated triphenylphosphine. 

Betzemeier et al. (1998) have used f-BuOOH, in the presence of a Pd(II) catalyst bearing perfluorinated ligands using a biphasic system of benzene and bromo perfluoro octane to convert a variety of olefins, such as styrene, p-substituted styrenes, vinyl naphthalene, 1-decene etc. to the corresponding ketone via a Wacker type process. Xia and Fell (1997) have used the Li salt of triphenylphosphine monosulphonic acid, which can be solubilized with methanol. A hydroformylation reaction is conducted and catalyst recovery is facilitated by removal of methanol when filtration or extraction with water can be practised. The aqueous solution can be evaporated and the solid salt can be dissolved in methanol and recycled. 

Tadic et al. studied the polymer poly-vynilidene fluoride/hexa-fluoropropylene ( PVdF/HFP ) containing lithium salt solution in Ethylene carbonate/diethylene carbonate ( EC/DEC )- In order to understand better the effect of anion size in the electrolyte, two Li salts were compared, namely LiN(CF3S02)2 (termed Liimide by the authors) and LiN(C2F5S02)2 (termed Libeti ). 

Figure 4.26. Yield distributions of 478 keV Li y-ray and 197 keV F y-ray for 4MeV protons in gel polymer samples containing different Li salts. The F y-ray yield is divided by 40. (After Tadic et al. 2000.)...

The Na salts in THF showed an intermediate behavior, and their spectra revealed an interesting temperature dependence. At + 25°C the spectra were very similar to those of the Li salts, but at - 52°C they had changed to the appearance of the spectra of the K salts. The spectra indicate a fast equilibrium 60 (X = Na) 61 with the latter favored by decreasing temperature. Analysis of the temperature dependence of individual chemical shifts allowed the evaluation of AH°, -6.9 kcal/mol, and AS0, -30 e.u., for this equilibrium (i.e., the contact-ion pairs are favored by entropy but disfavored by enthalpy). A similar effect may explain the temperature dependence of the NMR spectrum of 56. 

The Li salts of 59c and d, in which R has a greater donor capacity, exist solely as solvent-separated ion pairs. 

Structural data of phospholide ions themselves are scarce. The lithium salt of the tetramethylphospho-lide ion, which is in fact an y -complex, and the K salt of the 2,4,5-tri-terf-butyl-l,3-diphospholide an-ion have been reported. Also the structure of the Li salt of the 2,5-bis(ferf-butyl)-l,3,4-triphospholide ion has been obtained In all these structures the bond lengths are equalized (CC, 1.396—1.424 A CP, 1.690-1.752 A). 

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