Phospha-Wittig Reagents Rediscovered

Phospha-Wittig reagents, RPPMe₃ (R = Mes* 2,4,6-tBu₃-C₆H₂; ^MesTer 2,6-(2,4,6-Me₃C₆H₂)-C₆H₃; ^DipTer 2,6-(2,6-iPr₂C₆H₃)-C₆H₃), can be considered as phosphine-stabilized phosphinidenes. In this study we show that PMe₃ can be displaced by NHCs or NHOs. Interestingly, phosphinidene-like reactivity results in a subsequent C(sp²)-H activation of the exocyclic CH₂ in NHOs. This concept was further extended to allyl-apended NHOs, which results in phosphine-substituted allyl species.