Tert-Butyllithium

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Tert-Butyllithium

IUPAC name	2-Lithio-2-methylpropane
Other names	tert-Butyllithium
Identifiers
CAS number	[594-19-4]
Properties
Molecular formula	C₄H₉Li
Molar mass	64.05 g/mol
Appearance	colorless solid
Density	0.66 g·cm^-3
Melting point	36-40 °C
Solubility in water	decomp by water
Solubility	alkanes
Hazards
Main hazards	flammable
Related compounds
Related compounds	N-Butyllithium, sec-Butyllithium
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

tert-Butyllithium is the chemical compound with the formula (CH₃)₃CLi. This organolithium compound is used as an extremely strong base in certain applications of organic synthesis. The compound exists as a cluster, is capable of deprotonating many carbon acids, including benzene.

tert-Butyllithium is extremely flammable and ignites spontaneously in air. It must be kept and handled under a dry nitrogen atmosphere. Even with standard dry nitrogen conditions (such as a Schlenk line), this presents a hazard - if the ^tBuLi is drawn into a syringe through a septum, when the needle is removed the tip of the needle will catch fire - while this is not always a problem, the combustion can block the tube, leaving the chemist holding a tube of very dangerous solution with no means of delivering it back to the nitrogen atmosphere. The solution is to keep the tip of the needle in an inert atmosphere. A short glass tube, with a septum in each end, flushed with inert gas, is pierced with the needle and then the tip is drawn into the tube after the liquid has been drawn.

[edit] Chemical properties

The lithium carbon bond in tert-Butyllithium is strongly polarised. Chemically, it behaves like a carbanion, which can be showed by the resonance structures:^[1]

Similar to n-Butyllithium, tert-Butyllithium can be used for the exchange of lithium with halogenes and for the deprotonation of amines and activated C-H compounds. tert-Butyllithium can attack the alpha position of ethers. In the following example this is shown for tetrahydrofuran that decomposes within a few minutes at room temperature: