title: Methyltriphenylphosphonium bromide
text: # Methyltriphenylphosphonium bromide
  
  Methyltriphenylphosphonium bromide is the organophosphorus compound with the formula $[(C_6H_5)_3PCH_3]Br.$ It is the bromide salt of a phosphonium cation. It is a white salt that is soluble in polar organic solvents.
  
  ## Synthesis and reactions
  
  Methyltriphenylphosphonium bromide is produced by treating triphenylphosphine with methyl bromide:
  
      $Ph_3P$ + $CH_3Br$ → $Ph_3PCH_3Br$
  
  Methyltriphenylphosphonium bromide is the principal precursor to methylenetriphenylphosphorane, a useful methylenating reagent. This conversion is achieved by treating methyltriphenylphosphonium bromide with strong base.
  
      $Ph_3PCH_3Br$ + BuLi → $Ph_3PCH_2$ + LiBr + BuH
  