Organolithium reagents butyllithium

The reaction of butyllithium with 1-naphthaldehyde cyclohexylimine in the presence of (/C )-l,2-diphenylethane-1,2-diol dimethyl ether in toluene at —78 °C, followed by treatment with acetate buffer, gave 2-butyl-1,2-dihydronaphthalene-l-carbaldehyde, which was then reduced with sodium borohydride in methanol to afford (1 R,2.S)-2-butyl-1 -hydroxymcthyl-1,2-dihydronaphthalene in 80% overall yield with 91 % ee83. Similarly, the enantioselective conjugate addition of organolithium reagents to several a,/J-unsaturated aldimines took place in the presence of C2-symmetric chiral diethers, such as (/, / )-1,2-butanediol dimethyl ether and (/, / )- ,2-diphenylethane-1,2-diol dimethyl ether. 

The first stable silaallene, 56, was synthesized in 1993 " " by the intramolecular attack of an organolithium reagent at the /f-carbon of a fluoroalkynylsilane (Scheme 16). Addition of two equivalents of r-butyllithium in toluene at O C to compound 54 gave intermediate 55. The a-lithiofluorosilane then eliminated lithium fluoride at room temperature to form the 1-silaallene 56, which was so sterically hindered that it did not react with ethanol even at reflux temperatures. 1-Silaallene 56 was the first, and so far the only, multiply bonded silicon species to be unreactive toward air and water. The X-ray crystal structure and NMR spectra of 56 is discussed in Sect. IVA. 

Alternatively, organolithium reagents of the type (CH3)3SiCH(Li)Z, where Z is a carbanion-stabilizing substituent, can be prepared by deprotonation of (CH3)3SiCH2Z with -butyllithium. 

How well an organolithium reagent fares as an exchange component depends on its basicity. Thus, tert-butyllithium outperforms iec-butyllithium, which in turn is superior to butyllithium. MethyUithium is the least reactive alkyllithium but still surpasses phenyl-lithium, at least at low concentrations, i.e. the order is ... 

Standard organolithium reagents such as butyllithium, ec-butyllithium or tert-butyllithium deprotonate rapidly, if not instantaneously, the relatively acidic hydrocarbons of the 1,4-diene, diaryhnethane, triarylmethane, fluorene, indene and cyclopentadiene families and all terminal acetylenes (1-alkynes) as well. Butyllithium alone is ineffective toward toluene but its coordination complex with A/ ,A/ ,iV, iV-tetramethylethylenediamine does produce benzyllithium in high yield when heated to 80 To introduce metal into less reactive hydrocarbons one has either to rely on neighboring group-assistance or to employ so-called superbases. 

This reagent was obtained either from Aldrich Chemical Company, Inc., or Lithium Corporation of America, Bessemer City, NC. A technical data sheet is available from the suppliers. Solutions of ca. 2 M were titrimetrically analyzed for active alkyllithium by the tosylhydrazone method. It is advisable to make certain that the organolithium reagent to be used was prepared in pentane solution. This evaluation can be easily accomplished by the gas chromatographic analysis of the organic layer obtained from the hydrolysis, under a nitrogen atmosphere, of the tert-butyllithium solution to be used. Isobutane and pentane should comprise essentially all of the... 

Conjugate addition to a, -unsaturated esters.1 The unsaturated esters of this phenol undergo ready conjugate addition with a variety of organolithium reagents, with t-butyllithium providing the only exception. The adducts are oxidatively hydrolyzed to carboxylic acids by CAN (10, 162). 

Methylmagnesium N-cyclohexyliso-propylamide, 189 with organolithium reagents f-Butyllithium, 58 Lithium acetylide, 44 with functionalized carbon reagents Alkyldimesitylboranes, 8 Di- x-carbonylhexacarbonyIdicobalt, 99... 

Rli-rRNH2. Various organolithium reagents are converted into the corresponding primary amines by treatment with 2 equiv. each of methoxyamine and methyllithium in hexane-ether. Yields are in the range 55 95%. Omission of methyllithium or substitution by n-butyllithium markedly reduces the yield. In fact, use of methoxyamine alone for amination of organometallics was first reported in... 

Acyliron complexes have found many applications in organic synthesis [40]. Usually they are prepared by acylation of [CpFe(CO)2] with acyl chlorides or mixed anhydrides (Scheme 1.13). This procedure affords alkyl, aryl and a,P-unsaturated acyliron complexes. Alternatively, acyliron complexes can be obtained by treatment of [Fe(C5Me5)(CO)4]+ with organolithium reagents, a,P-Unsaturated acyliron complexes can be obtained by reaction of the same reagent with 2-alkyn-l-ols. Deprotonation of acyliron complexes with butyllithium generates the corresponding enolates, which can be functionalized by reaction with various electrophiles [40]. 

Several asymmetric 1,2-additions of various organolithium reagents (methyllithium, n-butyllithium, phenyllithium, lithioacetonitrile, lithium n-propylacetylide, and lithium (g) phenylacetylide) to aldehydes result in decent to excellent ee% (65-98%) when performed in the presence of a chiral lithium amido sulfide [e.g. (14)], 75 The chiral lithium amido sulfides invariably have exhibited higher levels of enantioselectivity compared to the structurally similar chiral lithium amido ethers and the chiral lithium amide without a chelating group. 

Other common, and commercially available, organolithium reagents include n-butyllithium and phenyllithium, and they react with both aldehydes and ketones. Note that addition to an aldehyde gives a secondary alcohol while addition to a ketone gives a tertiary alcohol. 

It is a tertiary alcohol with the hydroxyl group flanked by two identical R (= butyl) groups. The chemists who wanted to make the compound knew that an ester would react twice with the same organolithium reagent, so they made it from this unsaturated ester (known as methyl methacrylate) and butyllithium. 

It is sometimes more convenient to prepare organolithium reagents by halogen-lithium exchange between an aryl halide and butyllithium (BuLi). The reaction takes place because the aryllithium is more stable than butyllithium an sp- carbon is better able to stabilize a negative charge than an sp carbon (Scheme 10.2). Butyllithium is available commercially in bulk quantities. 

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