Lithium-ethylene compounds

Lithium organic compounds were obtained by 2e-reduction of 1,1-diphenyl-ethylene or tetraphenylethylene. The first olefin yielded quantitatively dilithio-1,1,4,4-tetraphenylbutane by dimerization of the intermediate radical anion (Eq. (244) ) whereas the second formed dilithiotetraphenylethane 62 2 K... 

NaNH2 in HMPA reacts at 45-50°C with diphenyl imines. The anion is alkylated in medium yields. In this case, best results are obtained with the use of lithium diethylamide (ref. 37). Tosylhydrazones are converted into ethylenic compounds (Fig. 6) by treatment with NaNH2 in decaline (ref. 38). 

Ethylenic compounds add carbenes, to form cyclopropane derivatives.10 Carbenes can be prepared by treating appropriate halogen compounds with an organometallic compound (e.g., butyllithium), -elimination of lithium chloride resulting ... 

So far, the discussion has covered the use of lithium or lithium compounds as catalysts for the polymerization of olefins or diolefins to solid polymers only. However, it is also possible to polymerize olefins to liquid polymers using catalysts comprised, in part, at least, of lithium compounds. Ziegler and his coworkers (52) reported on the reactions of lithium aluminum hydride with mono-olefins to form lithium aluminum tricycloalkyl hydrides, lithium aluminum tetraalkyls, and so on. According to a later patent (51), such lithium aluminum compounds can be used as catalysts for the polymerization of ethylene to polymers ranging from butene to wax-range solids. 

Regarding other termination reactions of the radical anion 38, the differences of AG with the corresponding reactions of LF(EC)2 are around 1.0 kcal/mol, e.g. 0.3 kcal/mol less negative for the Li carbide (50) generation, 0.6 and 1.4 kcal/mol more negative for lithium ethylene dicarbonate (48) and lithium diethylene dicarbonate (49), respectively, and nearly identical for the R-0-Li compound (51). This implies that the major effect of VC does lie in the initial step of the solvent reduction. 

An equilibrium has been invoked to account for the unusual chemistry of tris(phenylthio)methyl-lithium (74). Compound (74) in Scheme 8 may be made in several ways, and it undergoes cycloaddition with hetero-substituted olefins to give cyclopropanes. A selenium analogue of (74) has also been reported which gives a cyclopropane in 63% yield with l,l-bis(phenylthio)-ethylene. ... 

Quantitative Analysis of All llithium Initiator Solutions. Solutions of alkyUithium compounds frequentiy show turbidity associated with the formation of lithium alkoxides by oxidation reactions or lithium hydroxide by reaction with moisture. Although these species contribute to the total basicity of the solution as determined by simple acid titration, they do not react with allyhc and henzylic chlorides or ethylene dibromide rapidly in ether solvents. This difference is the basis for the double titration method of determining the amount of active carbon-bound lithium reagent in a given sample (55,56). Thus the amount of carbon-bound lithium is calculated from the difference between the total amount of base determined by acid titration and the amount of base remaining after the solution reacts with either benzyl chloride, allyl chloride, or ethylene dibromide. 

When lithium is used as a catalyst in conjunction with a chelating compound such as tetramethylethylenediarnine (TMEDA), telomers are generally obtained from toluene and ethylene (23), where n = 010. 

A second type of soHd ionic conductors based around polyether compounds such as poly(ethylene oxide) [25322-68-3] (PEO) has been discovered (24) and characterized. These materials foUow equations 23—31 as opposed to the electronically conducting polyacetylene [26571-64-2] and polyaniline type materials. The polyethers can complex and stabilize lithium ions in organic media. They also dissolve salts such as LiClO to produce conducting soHd solutions. The use of these materials in rechargeable lithium batteries has been proposed (25). 

Some instances of incomplete debromination of 5,6-dibromo compounds may be due to the presence of 5j5,6a-isomer of wrong stereochemistry for anti-coplanar elimination. The higher temperature afforded by replacing acetone with refluxing cyclohexanone has proved advantageous in some cases. There is evidence that both the zinc and lithium aluminum hydride reductions of vicinal dihalides also proceed faster with diaxial isomers (ref. 266, cf. ref. 215, p. 136, ref. 265). The chromous reduction of vicinal dihalides appears to involve free radical intermediates produced by one electron transfer, and is not stereospecific but favors tra 5-elimination in the case of vic-di-bromides. Chromous ion complexed with ethylene diamine is more reactive than the uncomplexed ion in reduction of -substituted halides and epoxides to olefins. ... 

Reaction of 2-chloromethyl-4//-pyrido[l,2-u]pyrimidine-4-one 162 with various nitronate anions (4 equiv) under phase-transfer conditions with BU4NOH in H2O and CH2CI2 under photo-stimulation gave 2-ethylenic derivatives 164 (01H(55)535). These alkenes 164 were formed by single electron transfer C-alkylation and base-promoted HNO2 elimination from 163. When the ethylenic derivative 164 (R = R ) was unsymmetrical, only the E isomer was isolated. Compound 162 was treated with S-nucleophiles (sodium salt of benzyl mercaptan and benzenesulfinic acid) and the lithium salt of 4-hydroxycoumarin to give compounds 165-167, respectively. 

A rather complex fused isoindoline (87) has been found to show good anorectic activity. This substance differs from other anorectic agents by not being a p-phenethylamine analogue. Preparation of this compound starts by reaction of a substituted benzoyl-benzoic acid (82) with ethylene diamine. The product (84) can be rationalized as being the aminal from the initially obtained monoamide 83. This is then subjected to reduction with lithium aluminum hydride... 

Triphenyl- [1] and trimethylvinylsilane [2] as well as l,l-bis(trimethylsilyl)ethylene [3] are known to react with lithium metal in THF yielding 1,4-dilithiobutane derivatives by a dimerizing Schlenk addition. Interestingly, by using hexane as the solvent trimethylvinylsilane 1 does not yield the dimer product 2 but a 1 1 -mixture of the corresponding vinyllithium compound 3 and the lithioalkyne 4... 

Starting with l,l-bis(trimethylsilyl)ethylene (5) in hexane or diethyl ether as the solvent we obtained another dimeric product, a monolithiumorganic compound 8 which was shown not to be formed by lithium hydride elimination from the 1,4-dilithiobutane derivative 6, the only product in THF as the solvent. Obviously the vinyllithium derivative 7, primarily formed in the same manner as vinyllithium from ethylene [4], in contrast to vinyllithium [4] does not add further lithium atoms but adds itself to the starting material 5 yielding 8 ... 

Redox shuttles based on aromatic species were also tested. Halpert et al. reported the use of tetracyano-ethylene and tetramethylphenylenediamine as shuttle additives to prevent overcharge in TiS2-based lithium cells and stated that the concept of these built-in overcharge prevention mechanisms was feasible. Richardson and Ross investigated a series of substituted aromatic or heterocyclic compounds as redox shuttle additives (Table 11) for polymer electrolytes that operated on a Li2Mn40g cathode at elevated temperatures (85 The redox potentials of these... 

A new development in silsesquioxane ehemistry is the eombination of sil-sesquioxanes with cyclopentadienyl-type ligands. Reeently, several synthetie routes leading to silsesquioxane-tethered fluorene ligands have been developed. The scenario is illustrated in Seheme 47. A straightforward aeeess to the new ligand 140 involves the 1 1 reaction of 2 with 9-triethoxysilylmethylfluorene. Alternatively, the chloromethyl-substituted c/oxo-silsesquioxane derivative 141 can be prepared first and treated subsequently with lithium fluorenide to afford 140. Compound 141 has been used as starting material for the preparation of the trimethylsilyl and tri-methylstannyl derivatives 142 and 143, respeetively, as well as the novel zirconoeene complex 144. When activated with MAO (methylalumoxane), 144 yields an active ethylene polymerization system. 

These catalysts require temperatures above 100° and usually 150-200° for reasonable rates. Alkylsodium compounds at their decomposition temperatures (50-90°) have also been used by Pines and Haag (9). Lithium reacted with ethylene diamine has also been reported by Reggel et al. (4) as a catalyst for this reaction. The homogeneous system thus formed seems to lower the temperature requirement to 100° (4), whereas the use of potassium amide in liquid ammonia requires 120° (S). Sodium reacted with ethylene diamine has been reported to be an ineffective catalyst (4)- The most active catalyst systems reported so far are high-surface alkali metals and activated-alumina supports. They are very effective at or near room temperature (10-12). 

This is a catalytic-chain mechanism because the agent which adds to the olefins is regenerated in the last step.The addition reaction of the anion to the olefin is similar to the noncatalytic reaction of alkyllithium compounds with ethylene as reported by Ziegler and Gellert 37) and by Bartlett et al. 38). In this reaction (5), the less stable secondary and tertiary alkyl lithium compounds add most readily. 

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