Allylidenetriphenylphosphorane is used as a wittig reagent for 1,3-diene synthesis and Michael addition reaction.
Allylidenetriphenylphosphorane is generally prepared from Allyltriphenylphosphonium Bromide
or chloride by treatment with n-Butyllithium or Phenyllithium. Structurally related analogs have been
prepared by the similar methods: 2-butenylidenetriphenylphosphorane; 3-methyl-2-
butenylidenetriphenylphosphorane; (E)-2-octenylidenetriphenylphosphorane; (E)-
pentadienylidenetriphenylphosphorane; (E)-2,4-hexadienylidenetriphenylphosphorane; 2-
alkynylidenetriphenylphosphorane; allylidenetributylphosphorane. γ-Alkyl-substituted
allylidenetriphenylphosphorane can be also obtained by the reaction of diisobutylaluminum
alkylideneamide with methylidenetriphenylphosphorane.
Allylidenetriphenylphosphorane must be prepared and transferred under inert gas (Ar or N2) to
exclude oxygen and moisture.
