Neopentyl lithium

Cavell also reported alkyl derivatives. Tetrabenzyl zirconium was found to react separately with one molar equivalent of two parent methanes to afford complexes 135 and 136 in excellent yields.66 The 13C NMR chemical shifts of the methandiide centres in 135 (Ad = adamantyl) and 136 of 82.8 and 84.4 ppm are clearly different from the dichloride congeners and reflect the substitution of the chlorides by alkyls. The corresponding hafnium dialkyl 137 was also prepared from 133 and neopentyl lithium and the methanide resonance for this complex appeared at 71.6 ppm in its 13C NMR spectrum.63 Noteably, these alkyls displayed far greater stability than their homoleptic tetraalkyl cousins. 

Alkane Carbon-Hydrogen Bond Activation), such behavior might not be expected of a monophosphine. However, in the reaction of [Rh(/u.-Cl)(COE)2]2 with four equivalents of PhCH2CH2PBu 2, this is observed as the product in (18) and conversion to (19) occurs on chloride abstraction (see also (174), Section 42). " A related situation is obtained when [Rh(/x-Cl)(Bu 2PCH2PBu 2)]2 is treated with neopentyl lithium where the highly unsaturated, 14-electron metal in the product, (20), is stabilized by an agostic interaction. ... 

A conceptual process for ethylene dimerization in the presence of tantalum or niobium based catalysts has been developed by MIT researchers [6-8]. The technology is based on a metal hydride-based homogeneous catalyst that selectively dimerizes ethylene to butene-1. The particular catalyst is neopentylidene complex of tantalum or niobium. The preparation of the homogeneous catalyst is rather a complex process the tantalum complex is prepared by reacting tri-neopentyl tantalum dichloride, Ta(CH2CMe3)3Cl2 and neopentyl lithium LiCH2CMe3 in octane solvent to yield thermally stable neopentylidene tantalum catalyst in quantitative yield. 

Reduction of [Yb(C5Me5)2DME]PF was performed with KH in DME at 20°C. Formation of Yb(C5Mc5)2DME with rapid hydrogen evolution was observed. A similar reaction occurs when neopentyl lithium was used instead of KH (Watson et al., 1981). 

Neopentyl alcohol has been made by lithium aluminum hydride reduction of trimethylacetic acid and by treating ferf-butyl-magnesium chloride with methyl formate. ... 

As first described by Krizan and Martin,6 the in situ trapping protocol, i.e., having the base and electrophile present in solution simultaneously, makes it possible to lithiate substrates that are not applicable in classical ortho-lithiation reactions.7 Later, Caron and Hawkins utilized the compatibility of lithium diisopropylamide and triisopropyl borate to synthesize arylboronic acid derivatives of bulky, electron deficient neopentyl benzoic acid esters.8 As this preparation illustrates, the use of lithium tetramethylpiperidide instead of lithium diisopropylamide broadens the scope of the reaction, and makes it possible to functionalize a simple alkyl benzoate.2... 

The reduction of di(neopentyl)gallium chloride with lithium naphthalide was reported to afford the gallium clusters (Ga-CH2CMe3) , but their structures are hitherto unknown. It was assumed that different species with up to 12 gallium... 

The reduction of free acids to alcohols became practical only after the advent of complex hydrides. Lithium aluminum hydride reduces carboxylic acids to alcohols in ether solution very rapidly in an exothermic reaction. Because of the presence of acidic hydrogen in the carboxylic acid an additional equivalent of lithium aluminum hydride is needed beyond the amount required for the reduction. The stoichiometric ratio is 4 mol of the acid to 3 mol of lithium aluminum hydride (Equation 12, p. 18). Trimethylacetic add was reduced to neopentyl alcohol in 92% yield, and stearic acid to 1-octadecanol in 91% yield. Dicarboxylic sebacic acid was reduced to 1,10-decanedioI even if less than the needed amount of lithiiun aluminum hydride was used [968]. 

Neopentyl sulfides have been prepared by alkylation of sodium sulfide with neopentyl tosylate in high-boiling polar solvents,4,5 or in low yields by reduction of alkyl 2,2-dimethylpropanethioate with the combination of lithium aluminum hydride and a large excess of boron trifluoride-etherate. ... 

Reaction of the diol with p-toluenesulfonyl chloride in pyridine, however, produced the ditosylate in nearly quantitative yield. SN2 displacements by chloride on neopentyl tosylate, which bears certain structural similarities to the ditosylate precursor of CAMPHOS, have been shown to give good yields of neopentyl chloride. However, when l,2,2-trimethyl-l,3-bis(hydroxymethyl)-cyclopentane ditosylate was allowed to react with sodium chloride in hexa-methylphosphoramide, in an attempt to form the dichloride, only N, A -dimethyl-p-toluenesulfonamide was isolated. Reaction of the ditosylate with lithium chloride in ethoxyethanol was exothermic and HC1 was evolved but the dichloride was not isolated. The isolated product contained at least one oleflnic bond. Similarly, in N, TV-dimethylformamide, lithium chloride and the ditosylate gave a product that decomposed on distillation. Faced with such repeated failures, a dihalide route to CAMPHOS was abandoned in favor of a more direct approach reaction of the ditosylate with diphenylphosphide anion. 

In the reaction of the neopentyl iodide radical probe 108 with lithium propiophenone in HMPA, the O-substituted 109 (66%) and the C-substituted 110 compounds (11%) were... 

Fluorination of carbanions. These reagents selectively fluorinate a broad variety of carbanions in fair to good yield. Oxygen and nitrogen anions are not affected. The base can be NaH, KH, orn-BuLi, although lithium enolates are less reactive than potassium enolates. Nonpolar solvents are preferable to DMF, THF, or ether. Strongly basic anions can effect p-elimination of HF from 1 when R - CH,. Elimination is suppressed when R = neopentyl or norbomyl. 

Organometallic compounds of magnesium, mercury, or lithium have been treated with iodine or bromine to form organic halides. The method has been successful for obtaining neopentyl iodide where other methods have failed (92%). It has been found convenient in the synthesis of 9-iodoanthracene (53%) and certain heterocyclic halides. ... 

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