Double Arbuzov Reaction. Synthesis of Bis(ω-cyanoalkyl)phosphinic Acids

A general method for the synthesis of symmetric bis(ω-cyanoalkyl)phosphinic acids from ammonium hypophosphite was proposed. The reaction of bis(trimethylsilyl)hypophosphite generated in situ with the ω-bromoalkylnitrile molecule according to the Arbuzov reaction and the subsequent silylation of the hydrophosphoryl intermediate leads to the formation of bis(trimethylsilyl)phosphonite. The latter reacts with the second ω-haloalkylnitrile molecule by the Arbuzov reaction with the formation of the second phosphorus-carbon bond.