Benzylpotassium is an
organopotassium compound
Organosodium chemistry is the chemistry of organometallic compounds containing a carbon to sodium chemical bond. The application of organosodium compounds in chemistry is limited in part due to competition from organolithium compounds, which are ...
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 Transmetalation (alt. spelling: transmetallation) is a type of organometallic reaction that involves the transfer of ligands from one metal to another. It has the general form:
:M1–R + M2–R′ → M1–R′ + M2–R
where R and R′ can be, but ...
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) at ...
.
[{{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 com ...
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