A 2‐Phosphonio‐Substituted 1‐Phospha‐1‐alkene: Resonance between P^{<scp>III</scp>} Alkene and P^<scp>V</scp> Ylide

Abstract

How realistic is a resonance of the type A ↔ B ↔ C? This question could be answered from the NMR spectroscopic data of 1, the first representative of the 2-phosphonio-substituted 1-phospha-1-alkenes. A considerable amount of the resonance structures B and C was found in the actual structure of 1 (R = 2,4,6-tBu3C6H2).