Methyltriphenylphosphonium bromide is the
organophosphorus compound
Organophosphorus compounds are organic compounds containing phosphorus. They are used primarily in pest control as an alternative to chlorinated hydrocarbons that persist in the environment. Some organophosphorus compounds are highly effective in ...
with the formula
6H5)3PCH3">C6H5)3PCH3r. It is the bromide salt of a
phosphonium
In polyatomic cations with the chemical formula (where R is a hydrogen or an alkyl, aryl, or halide group). These cations have tetrahedral structures. The salts are generally colorless or take the color of the anions.
Types of phosphonium ...
cation. It is a white salt that is soluble in polar organic solvents.
Synthesis and reactions
Methyltriphenylphosphonium bromide is produced by treating
triphenylphosphine
Triphenylphosphine (IUPAC name: triphenylphosphane) is a common organophosphorus compound with the formula P(C6H5)3 and often abbreviated to P Ph3 or Ph3P. It is widely used in the synthesis of organic and organometallic compounds. PPh3 exists a ...
with
methyl bromide
Bromomethane, commonly known as methyl bromide, is an organobromine compound with formula C H3 Br. This colorless, odorless, nonflammable gas is produced both industrially and biologically. It has a tetrahedral shape and it is a recognized ozon ...
:
:Ph
3P + CH
3Br → Ph
3PCH
3Br
Methyltriphenylphosphonium bromide is the principal precursor to
methylenetriphenylphosphorane
Methylenetriphenylphosphorane is an organophosphorus compound with the formula Ph3PCH2. It is the parent member of the phosphorus ylides, popularly known as Wittig reagents. It is a highly polar, highly basic species.
Preparation and use
Methylen ...
, a useful methylenating reagent. This conversion is achieved by treating methyltriphenylphosphonium bromide with strong base.
[{{cite journal, doi = 10.1080/00397918508063883, title = The Wittig Reaction Using Potassium-tert-butoxide High Yield Methylenations of Sterically Hindered Ketones, year = 1985, last1 = Fitjer, first1 = Lutz, last2 = Quabeck, first2 = Ulrike, journal = Synthetic Communications, volume = 15, issue = 10, pages = 855–864]
:Ph
3PCH
3Br + BuLi → Ph
3PCH
2 + LiBr + BuH
References
Quaternary phosphonium compounds
Bromides