In organophosphorus chemistry, the Kinnear–Perren reaction (sometimes the Clay-Kinnear-Perren reaction) is used to prepare alkylphosphonyl dichlorides (RP(O)Cl2) and alkylphosphonate esters (RP(O)(OR')2).
[1] The reactants are alkyl chloride, phosphorus trichloride, and aluminium trichloride as catalyst.
[2] The reaction proceeds via the alkyltrichlorophosphonium salt: Reduction of this trichlorophosphonium intermediate with aluminium powder gives alkyldichlorophosphines (RPCl2).
Partial hydrolysis of the same intermediate gives the alkylphosphonyl dichloride: The reaction was first reported by Clay[3] and expanded upon by Kinnear and Perren, who demonstrated that the four chlorinated methanes (CH4−xClx) give the corresponding CH3-, CH2Cl-, CHCl2-, and CCl3-substituted derivatives.
They also demonstrated workup with hydrogen sulfide to give the alkylthiophosphoryl dichlorides.