Benzylpotassium is an
organopotassium compound with the formula C
6H
5CH
2K. It is an orange powder. Like organo-alkali metal reagents in general, benzyl potassium is highly reactive, so much so that it reacts with most solvents. It is highly air sensitive.
Synthesis
One early synthesis proceeds by two-step
transmetallation reaction via ''p''-tolylpotassium:
:(CH
3C
6H
4)
2Hg + 2 K → 2 CH
3C
6H
4K + Hg
:CH
3C
6H
4K → KCH
2C
6H
5
A modern synthesis involves the reaction of
butyllithium Butyllithium may refer to one of 5 isomeric organolithium reagents of which 3 are commonly used in chemical synthesis:
* ''n''-Butyllithium, abbreviated BuLi or nBuLi
* ''sec''-Butyllithium, abbreviated ''sec''-BuLi or sBuLi, has 2 stereoisomers, ...
,
potassium ''tert''-butoxide, and
toluene
Toluene (), also known as toluol (), is a substituted aromatic hydrocarbon. It is a colorless, water-insoluble liquid with the smell associated with paint thinners. It is a mono-substituted benzene derivative, consisting of a methyl group (CH3) ...
.
[{{cite journal , doi = 10.1016/0022-328X(87)80117-1, title = Lithium-potassium exchange in alkyllithium/potassium t-pentoxide systems, journal = Journal of Organometallic Chemistry, volume = 326, pages = 1, year = 1987, last1 = Lochmann, first1 = L, last2 = Trekoval, first2 = J] Although
potassium hydride
Potassium hydride, KH, is the inorganic compound of potassium and hydrogen. It is an alkali metal hydride. It is a white solid, although commercial samples appear gray. It is a powerful superbase that is useful in organic synthesis. It is sold ...
can also be used as a strong base for preparing potassium salts, benzyl potassium has the advantage of being molecular and hence more fast-acting.
References
Potassium compounds
Benzyl compounds