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Potassium t-Butoxide

Other Names:

Potassium tert-butoxide

Potassium tert-butylate

Potassium 2-methylpropan-2-olate


General Information:


CAS Number: 865-47-4

Molecular Weight: 112.21 g/mol

Appearance: White solid

Chemical Formula: KOC(CH3)3

Potassium t-butoxide (t-BuOK) is a strong, non-nucleophilic base. The pKa of its conjugate acid is about 17. Similar bases include sodium t-butoxide (t-BuONa) and lithium t-butoxide (t-BuOLi).

Common Uses:

Base in Wittig reactions

Procedure excerpt:

To a solution of the SM (5.22 g, 29.0 mmol) and methyl triphenylphosphonium bromide (12.4 g, 34.8 mmol) in THF (100 mL) was added tBuOK (1.0M in THF, 34.8 mL, 34.8 mmol) . . .

[full procedure]


Potassium t-butoxide (t-BuOK) is a strong alkoxide base. It is a hygroscopic powder that should be stored and handled under an inert atmosphere.


1) Patent Reference: WO2010045258, page 82, (12.0 MB)

2) Wikipedia: Potassium tert-butoxide (link)

3) Potassium tert-butoxide (link)

4) Reich, H. J.; Rigby, J. H.; Handbook of Reagents for Organic Synthesis, Acidic and Basic Reagents