Variable Reactivity of a N-Heterocyclic Phosphenium Complex: P−C Bond Activation or “Abnormal” Deprotonation

Abstract The reaction of an N‐heterocyclic phosphenium complex of manganese with MeLi/Et 3 NHCl under formal addition of CH 4 to the Mn=P double bond can be reversed upon UV photolysis, providing a rare example for selective P−C(alkyl) bond activation. Action of LDA on the phosphenium complex does not proceed via attack at phosphorus but rather via C4‐deprotonation to yield a unique P‐analogue of an “abnormal” carbene. A transmetalation product of the original complex was fully characterized. The C‐metalation is also applicable to bis‐phosphenium complexes of other metals.