Butyllithium reagents

Butyllithium reagents, with chromium, 5, 382 Butyl(tri-2-pyridyl)stannane, preparation, 3, 827 ft-Butylvanadium(III) complex, preparation, 5, 19... 

Titrate the butyllithium reagent immediately before using it to prepare a lithium amide. 

The solvent for the reaction with the alkali metal, metal hydride, and so on, is often the alcohol itseh. However, on occasion, such as when the alcohol is not a liquid or when other functional groups with which the alkoxide anion might react are present, ethers or hydrocarbons are used as solvents. Commercially available butyllithium reagents are sold as solutions in hydrocarbon solvents. 

Alkyllithium bases are generally less suitable for deprotofiation of compounds with strongly electron-withdrawing groups such as C=0, COOR and CsN. In these cases lithium dialkylamides, especially those with bulky groups (isopropyl, cyclohexyl), are the reagents of choice. They are very easily obtained from butyllithium and the dialkylamine in the desired solvent. 

These conditions are so harsh that they are applicable only to indoles with the most inert substituents. Cyclization can be achieved at much lower temperatures by using alkyllithium reagents as the base. For example, treatment of o-methylpivalanilide with 3 eq. of n-butyllithium at 25 C gives 2-terr-butylindole in 87% yield[2]. These conditions can be used to make... 

Caution tevt-Butyllithium ie pyvophovia in air exaeee quantities of the reagent in the syringe should be discarded oery carefully- The checkers used the reagent available from Aldrich Chemical Company Ltd., England and standardized it by double titration with ethylene dibromide and hydrochloric acid. ... 

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