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 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 ...

: :Ph₃P + CH₃Br → Ph₃PCH₃Br 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 :Ph₃PCH₃Br + BuLi → Ph₃PCH₂ + LiBr + BuH

References

Quaternary phosphonium compounds Bromides