[15935-94-1] C₂₁H₁₉P (MW 302.36)

InChI = 1S/C21H19P/c1-2-18-22(19-12-6-3-7-13-19,20-14-8-4-9-15-20)21-16-10-5-11-17-21/h2-18H,1H2

InChIKey = KTXDDSBSRMDZLM-UHFFFAOYSA-N

(Wittig reagent for 1,3-diene synthesis² and Michael addition reaction³)

Physical Data: ¹³C and ³¹P NMR solution studies,⁴ X-ray structures of the molybdenum and tungsten complexes,⁵ and the heat of formation (ΔH) have been reported.⁶

Solubility: sol THF,⁷ toluene.⁸

Form Supplied in: prepared in situ and used directly.

Preparative Methods: this Wittig reagent is generally prepared from Allyltriphenylphosphonium Bromide or chloride by treatment with n‐Butyllithium or Phenyllithium.^{2, 3, 9} Structurally related analogs have been prepared by the similar methods: 2-butenylidenetriphenylphosphorane;¹⁰ 3-methyl-2-butenylidenetriphenylphosphorane;¹⁰ (E)-2-octenylidenetri phenylphosphorane;¹¹ (E)-pentadienylidenetriphenylphosphorane;¹¹ (E)-2,4-hexadienylidenetriphenylphosphorane;¹² 2-alkynylidenetriphenylphosphorane;¹² allylidenetributylphosphorane.¹³ γ-Alkyl-substituted allylidenetriphenylphosphorane can be also obtained by the reaction of diisobutylaluminum alkylideneamide with methylidenetriphenylphosphorane.¹⁴

Handling, Storage, and Precautions: must be prepared and transferred under inert gas (Ar or N₂) to exclude oxygen and moisture.