Generation of α-Phosphinocarbene Complexes and Their Evolution: New Light on Relevant Isomerization Pathways
Résumé
The η1-α-phosphinocarbene complex Cp(CO)2Mn═CR(PHMes) (R = Ph, Me) is generated by nucleophilic attack of MesPH2 at the electrophilic center of the cationic Mn−carbyne complex [Cp(CO)2Mn≡CR]+, followed by deprotonation. One of its identified isomerization pathways to η1-phosphaalkene derivatives is shown to be both base-catalyzed and stereoselective, and to involve a transient phosphidocarbene species engaged in an acid-catalyzed migratory CO-insertion step.