A-Butyllithium

Diisopropylamine (Merck AC, D-Darmstadt) is distilled from calcium hydride and stored over molecular sieves (3 A). Butyllithium (15% solution in hexane) was purchased from Merck AG, D-Darmstadt. 

Several workers (l. 2,3,4) have used H nmr to study the propagating chain end in the polymerization of 1,3-butadiene (1,3 BD) with a butyllithium initiator. They concluded that the poly(butadienyl) lithium chain end is virtually ICO percent 1,4 with no 1,2 structures, even though 1,2 units are incorporated in the chain. The lithium is bonded to the carbon, and there is no evidence of a T allyl type of delocalized bonding involving the Y carbon. However, the presence of vinyl in-chain units was taken as evidence for the presence of an undetectable amount of the 7 bonded chain ends in equilibrium with the bonded chain ends. Glaze and coworkers (3) further suggested that the stereochemical course of allyllithium reactions may depend on the aggregation of the reactive species. 

Butylpotassium and butylcesium deprotonate furan at the 2-position (75BSF1302), but butyllithium is the reagent of choice. When furan is treated with butyllithium the reactions in Scheme 114 occur (77JCS(P1)887>. The conditions, however, may be controlled to yield predominantly the mono- or the di-lithio derivative. By carbonation and esterification of the reaction mixture obtained by treatment of furan with butyllithium and TMEDA (1 1 1) in ether at 25 °C for 30 min, a 98% yield of methyl furan-2-carboxylate is obtained. Similarly, a butyllithium TMEDA furan ratio of 2.5 2.5 1 in boiling hexane for 30 min results in 91% of dimethyl furan-2,5-dicarboxylate and 9% of the monoester. Competition experiments indicate that furan reacts with butyllithium faster than thiophene under non-ionizing conditions but that the order is reversed in ether or in the presence of TMEDA. 

Isotactic Polystyrene. The familiar steam molding of pre-expanded particles has so far not been applied successfully to isotactic polystyrene. However, the polymer has been foamed, according to three disclosed methods. For example, finely divided acetone-insoluble polymer, with a melting point in excess of 200°C., is blended with a liquid selected from methylene chloride, aromatic hydrocarbons, or halogenated aromatic hydrocarbons. This blend is then heated (84). A mixture of molten polymer and methyl chloride, propane, or butane is suddenly depressurized (8). Foam may also be generated in a continuous manner directly from a butyllithium-initiated polymerization conducted in the presence of a 4/1 blend of benzene and petroleum ether (15). 

The action of buQ Uithium on thioanisole in THF generates (phenylthio)methyllithium in a low yield of 35%. - Corey and Seebach found that reaction of equimolar amounts of bu Uithium, DABCO and thioanisole in THF at 0 "C produces (phenylthio)methyllithium in ca. 97% yield. Dimethyl sulfide can be metalated with a butyllithium-TMEDA complex at room temperature (equation 1). Treatment of chloromethyl p-tolyl sulfide with magnesium produces the corresponding Grignard reagent a reaction temperature between 10 and 20 C is crucial for its efficient generation (equation 2). ... 

Cyclopropyl phenyl selenides are inert towards lithium diisopropylamide (LDA) and lithium tetra-methylpiperidide (LiTMP) (Scheme 14, a). Butyllithiums instead react on the selenium atom and pro-duce butyl cyclopropyl selenides and phenyllithium rather than cyclopropyllithiums and butyl phenyl selenides (Scheme 14, b). 

The reaction, at low temperature, of a butyllithium excess on the monohalogenated diphos-phiranes(2f- g) in diethylether, causes ring opening by cleavage of the P—P bond and leads to a quantitative formation of 1,3-diphosphapropenes (Scheme 5) <89NJC315>. The reaction is stereospecific and gives only the trans isomers. 

If the methylation is performed on Cs[CBi 1H12]13 instead of the commercial Me3NH[CBnHi2], using 1.5 equiv of a-butyllithium and 2 equiv of methyl iodide, it proceeds to completion and a second step is not required. 

A. 4,4 -Bis[(trimethylsilyl)methyl]-2,2 -bipyridine. A 500-mL, two-necked, round-bottomed flask (Note 1), equipped with a nitrogen inlet, magnetic stirrer, and rubbei septum is charged with tetrahydrofuran (THF) (90 mL) (Note 2) and diisopropyiamine (9.8 mL, 69.7 mmol) (Note 3). The reaction mixture is cooled to -78X and a solution a butyllithium (n-BuLi) (1.7 M in hexanes, 36.0 mL, 61.4 mmol) (Note 4) is added. The solution is stirred at -78°C for 10 min, warmed to 0°C and stirred for 10 min, ther cooled back to -78°C. A solution of 4,4,-dimethyl-2,2 -bipyridine (5.14 g, 27.9 mmol)... 

Pyrrole A-hydrogen is much more acidic (p 17.5) than that of a comparable saturated amine, say pyrrolidine (p 44), or aniline 30.7), and of the same order as that of 2,4-dinitroaniline. Any very strong base will effect complete conversion of an A-unsubstituted pyrrole into the corresponding pyrryl anion, perhaps the most convenient being commercial A -butyllithium in hexane, however, reactions at nitrogen can proceed via smaller, equilibrium concentrations of pyrryl anion, as in the formation of 1-chloropyrrole (in solution) by treatment with sodium hypochlorite or the preparation of 1-f-butoxycar-bonylpyrrole. ... 

In the case of poly(ethylene terephthalate) film exposed to allyl alcohol, the film is treated with a butyllithium solution to form the nucleophilic alkoxide ion. This film is then derivatized with the cyanuric chloride. The hydroxyl end groups of polyethylene glycol are reacted with butyllithium to form the alkoxide derivative and... 

Manabe S. Enantioselective [2,3]-sigmatropic rearrangement mediated by a butyllithium-chiral ligand complex. J. Chem. Soc., Chem. Commun. 1997 (8) 737 738. 

Fif ure 2. Dipropylene glycols resulting from a-butyllithium cleavage of polyfpropylene oxide)... 

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