title: McCormack reaction
text: # McCormack reaction
  
  The McCormack reaction is a method for the synthesis of organophosphorus compounds. In this reaction, a 1,3-diene and a source of $R_2P^+$ are combined to give phospholenium cation. The reaction is named after W. B. McCormack, a research chemist at duPont.
  
  An illustrative reaction involves phenyldichlorophosphine and isoprene:
  
  The reaction proceeds via a pericyclic [2+4]-process. The resulting derivatives can be hydrolyzed to give the phosphine oxide. Dehydrohalogenation gives the phosphole.
  
  