Formation of a Vinyliminium Palladium Complex by C−C Coupling in Vinylcarbene Palladium Aryl Complexes

Pentafluorophenyl palladium complexes 3 and 5 bearing a vinylcarbene ligand slowly decompose on
heating by migratory insertion to give Pd(0) and the vinyliminium salts (Et2NC(C6F5)CHCHPh)X
(X = Br, BF4). However, the presence of triphenylphosphine in complex 4 stabilizes 7, a compound
with a CC Pd-bound vinyliminium moiety, where there is a strong preference for the CC versus the
CN coordination.