Reactivity of phospha-Wittig reagents towards NHCs and NHOs
Gupta P., Siewert JE., Wellnitz T., Fischer M., Baumann W., Beweries T., Hering-Junghans C.
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 PMe3can be displaced by NHCs or NHOs. Interestingly, phosphinidene-like reactivity results in a subsequent C(sp2)-H activation of the exocyclic CH2group in NHOs. This concept was further extended to allyl-apended NHOs, which resulted in phosphine-substituted allyl species.