Butyllithium in Diethyl Ether

Lithium containing 1-2 % of sodium must be used. Analytically pure lithium gives lower yields. 

The remaining lithium is immediately destroyed by adding 150 ml of ethanol (containing about 30 % of water). 

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The alkylations proceeded much more slowly, when ethyl- or butyllithium in diethyl ether, prepared from the alkyl bromides, had been used for the metallation of allene, in spite of the presence of THF and HMPT as co-solvents. 

When treated with butyllithium in diethyl ether at —50°C, bromobenzene undergoes the permutational exchange of the halogen against the metal only slowly, but rapidly at 0 °C. The transformation is complete after a few seconds if conducted in tetrahydrofuran at —75 °C. lodobenzene reacts instantaneously in any case. 

TABLE 21. Chloro-, bromo- and iodo-substituted aryUithiums Li—R by halogen/metal permutation between bromoarenes and butyllithium in diethyl ether... 

The dibromoalkene S-40 can be prepared from S-ethyl lactate by introduction of the MEM (methoxyethoxymethyl) protecting group, reduction to the O-protected lactaldehyde and Corey-Fuchs carbonyl olefination (Scheme 19). The l -enantiomer of 40 is available analogously from f -isobutyl lactate and serves as the reagent in the enantiomeric series. The lithium carbenoid S-41 is generated from S-40 by treatment with n-butyllithium in diethyl ether and reacted with aliphatic and aromatic aldehydes in tetrahydrofuran. High diastereoselectivities are reached, as shown in Scheme 19 . ... 

Lithio-l-methoxyallene 183 ° , readily accessible by deprotonation of methoxyal-lene with n-butyllithium in diethyl ether, turned out to be a versatile C-3 building blocL It adds to aldehydes and ketones giving hydroxyaUcylated allenes 184, which undergo a ring-closure reaction under basic conditions. Thus, 3-methoxy-2,5-dihydrofurans 185 are obtained. Subsequent acid hydrolysis leads to the formation of dihydro-3(2//)-... 

Brandsma and coworkers were able to show that meta- (59a) and para-dilithiated benzene (59b) are accessible via iodine-lithium exchange, using n-butyllithium. Therefore, 1,3- and 1,4-diiodobenzene (58a and 58b) respectively were reacted with two equivalents of n-butyllithium in diethyl ether at low temperatures (Scheme 21). The polyUthiation was confirmed by trapping reactions with dimethyl disulphide. The same reactions, starting from the corresponding dibromobenzenes, had led only to monolithiated benzenes. 

When hexachloro-1,3-butadiene (81) is reacted with four equivalents of n-butyllithium in diethyl ether, a series of lithiation and elimination reactions gives l,4-dilithio-l,3-butadiyne (82) in good yields (Scheme 30). Ijadi-Maghsoodi and Barton verified this by derivatization with various chlorosilanes in yields up to 94%". ... 

In our group, the tin-lithium exchange has been used to synthesize the doubly lithiated dimethyl sulphane 99 by the reaction of bis(tributylstannomethyl)sulphane (98) with two equivalents of n-butyllithium in diethyl ether". Two equivalents of tetrabutylstannane are cleaved off in this reaction (Scheme 34). 

Variously substituted siloles of type 129 could be synthesized by Tamao and coworkers by the reaction of l,4-diaryl-l,4-dilithio-l,3-butadienes of type 128 with chlorosilanes . The l,l -spirobisilole 130 was accessible by reaction of the diphenyl snbstitnted dilithium compound 128a with tetramethoxysilane (Scheme 47). All of the dilithium compounds 128a-e were obtained by reaction of 2,5-diaryltellurophenes 127a-e with i-butyllithium in diethyl ether. 

Like their sulfur counterparts (Section 3.2.4.4.2.), 1 -lithiocyclopropyl selenides 1, as generated by reductive lithiation of bis(selanyl)cyclopropanes 173 with butyllithium in diethyl ether or tetrahydrofuran, react with aldehydes or ketones to give /Lhydroxy selenides 2, which rearrange to cyclobutanones 3 on treatment with p-toluenesulfonic acid in wet benzene.174 175 The method was used in a total synthesis of a-cuparenone.175... 

Grignard reagents fail to react with dihydro-1,3-oxazines unsubstituted at C-2, but n-butyllithium in diethyl ether yields 2-butyltetrahydro-l,3-oxazines. However, the reaction is solvent-dependent and in THF the ring is opened to give isocyanides (69TL5151). 

Red crystals of compound 134 were isolated from the lithiation of diphosphirane 133 with -butyllithium in diethyl ether at -70°C. The formation of the 1,3-diphosphaallyl anion results from a P-P bond cleavage. In the product the exo-exo position of the aryl groups confirms the theoretically predicted conrotatory anionic ring opening. A cr-allyl character agrees with the P-Li coupling constants (Equation 11) <1996JOM(514)37>. 

The reaction of the azetidinium salt 1 with an excess of butyllithium in diethyl ether at room temperature for 24 hours produced a mixture of six amines in 80% yield, among which the formation of l-dimethylamino-2,2-dimethylcyclopropane (6) has been shown. But, due to... 

FormylbenzotelluropheneP Benzotellurophene (2.3 g, 10 mmol) is dissolved in 15 mL of dry diethyl ether, and a solution of 11 mmol of n-butyllithium in diethyl ether is added dropwise. The mixture is stirred for 0.5 h and then 1.0 g (14 mmol) of dimethylformamide in 10 mL of diethyl ether is added. The yellow product is isolated by normal work-up of the reaction mixture yield 1.5 g (60%) m.p. 108°C. 

Imidazoles substituted in the 1-position, e.g. 1-methylimidazole, react with -butyllithium in diethyl ether to form the corresponding 2-lithioimidazoles [113] ... 

N-Methylindole (180) and -butyllithium were mixed in flow over 15 min at room temperature. To newly formed lithio species 181 was added a stoichiometric amount of carbon dioxide via a mass flow controller. After less than 1 min, a solution of -butyllithium in diethyl ether was added the reaction flowed through the column for 10 min at room temperature and was quenched with 1 M HCl to afford the desired ketone in 79% yield. Of particular note is the observation that the organolithium in the second addition was found to be far more reactive as a solution in diethyl ether compared to THF (14AG(I)8416). 

It is worth mentioning that the substituted cyclohexanone was also formed from the iodocyanopentane when lithiated with n-butyllithium in diethyl ether. The halogen exchange reaction is obviously much faster than nitrile addition for the organolithium reagent (see also the reaction mentioned on p.96. 

Under the optimized conditions, allyl 2-bromophenyl ethers were treated with 2.0 equiv. of tert-butyllithium in diethyl ether at —78 °C to afford allyl 2-lithiophenyl ethers 166, which were stable at low temperature. Addition of TMEDA to the reaction mixture, followed by warming to 0°C, and subsequent treatment with various electrophiles led to the functionalized dihydrobenzofuran derivatives 165 in moderate to good yields (Scheme 10.53, path A). It is interesting to note that the 1,3-elimination pathway (Scheme 10.53, path B) could be avoided. Furthermore, this intramolecular carbolithiation reaction was completely diastereoselective, and only the trans diastereomers were obtained. This stereochemistry was explained considering the chairlike transition state 166 in which the a-substituent predominantly occupies a pseudoequatorial position resulting in high levels of... 

The base-promoted rearrangement of 2-halo-1,1-diarylethenes (2,2-diarylvinyl halides) was discovered by Paul Fritsch and his research associates Wilhelm Buttenberg and Heinrich Wiechell more than a century ago. 2-Chloro-l,l-diphenylethene heated in a sealed tube with an ethanolic solution of sodium ethoxide to 200 °C was found to produce a mixture of tolane (diphenylacetylene) and 2-ethoxy-l,l-diphenylethene. The alkyne was obtained in much higher yield with fused potassium hydroxide or with potassium amide in liquid ammonia. Tolane is formed instantaneously and quantitatively when 2-chloro-l,l-diphenylethene is treated with n-butyllithium in diethyl ether at -35 or at -75 The same happens when... 

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