Butyllithium, reaction with

Nate 7. An excess of butyllithium is used, as some butyllithium is destroyed by the competing reaction with the THF. 

Methylthiophene is metallated in the 5-position whereas 3-methoxy-, 3-methylthio-, 3-carboxy- and 3-bromo-thiophenes are metallated in the 2-position (80TL5051). Lithiation of tricarbonyl(i7 -N-protected indole)chromium complexes occurs initially at C-2. If this position is trimethylsilylated, subsequent lithiation is at C-7 with minor amounts at C-4 (81CC1260). Tricarbonyl(Tj -l-triisopropylsilylindole)chromium(0) is selectively lithiated at C-4 by n-butyllithium-TMEDA. This offers an attractive intermediate for the preparation of 4-substituted indoles by reaction with electrophiles and deprotection by irradiation (82CC467). 

Modification of functional groups incorporated in a heterocycle is possible via ylide reactions. The 5-methylisoxazole (578) on reaction with n-butyllithium and methanesulfenyl... 

Thiadiazole, 2-methyl-5-pheny 1-reactions with butyllithium, 6, 563... 

Thiophene, bromotetrahydromethyl-pyrolysis, 3, 902 Thiophene, 5-t-butyl-2-methyl-dealkylation, 4, 800 Thiophene, chloro-polymerization, 4, 758 reaction with n-butyllithium, 4, 831 synthesis, 4, 835, 882, 933 Thiophene, 2-chloromercurio-reactions... 

Most other studies have indicated considerably more complex behavior. The rate data for reaction of 3-methyl-l-phenylbutanone with 5-butyllithium or n-butyllithium in cyclohexane can be fit to a mechanism involving product formation both through a complex of the ketone with alkyllithium aggregate and by reaction with dissociated alkyllithium. Evidence for the initial formation of a complex can be observed in the form of a shift in the carbonyl absorption band in the IR spectrum. Complex formation presumably involves a Lewis acid-Lewis base interaction between the carbonyl oxygen and lithium ions in the alkyllithium cluster. 

Thiophenedithiol (170) has been prepared by halogen-metal interconversion between the lithium salt of 4-bromo-3-thiophenethiol and n-butyllithium at —70°C, followed by reaction with sulfur/ IR, NMR, and UV spectra showed that this compound exists in the dithiol form (170). The compound obtained as a by-product in the... 

Dehydration to 2-vinylthiophene is better achieved from 2-(2-thienyl) ethanol with powdered potassium hydroxide in the presence of copper than from 1-(2-thienyl) ethanol. a-Chloro-2-thienylpro-pane undergoes a Wurtz reaction with active iron to give 3,4-di-(2-thienyl) hexane in low yield, which has also been obtained through coupling with n-butyllithium. ... 

The nucleophilic properties of phosphorus in phosphaferrocene were demonstrated by reaction with n-butyllithium occurring at the phosphorus atom (81IC3252 820M312). 

It is noteworthy that carbene function may be manifested in the derivatives of tris(imidazol-l-yl)borate 44 (96AGE310). Its reaction first with n-butyllithium, then with iron(II) chloride, and finally with sodium tetraphenylborate gives the iron(III) carbene derivative 45. 

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