Vanadium Pentafulvene Complexes: Synthon for Unprecedented VanadoceneIIIDerivatives

Abstract

AbstractThe benzene ligand at CpV(η6−C6H6) (1) is exchanged for pentafulvenes. Using sterically demanding pentafulvenes gives a clean exchange reaction, yielding vanadium pentafulvene (2 aand2 b) and benzofulvene complexes (3 aand3 b). The molecular structures of the target compounds suggest a π‐η5:σ‐η1coordination mode with a vanadiumIIIcenter. With the sterically low demanding 6,6‐dimethylpentafulvene, a C−H activation at the leaving ligand is observed, yielding the ring‐substituted vanadoceneII4. The reactivity of the pentafulvene complexes was investigated. A series of unprecedented vanadoceneIIIcompounds were synthesized: Under mild conditions, E−H splitting of 4‐tert‐butylphenol, diphenylamine, and 2,6‐diisopropylaniline yield well characterized examples of rare vanadoceneIIIphenolate and amide complexes. Insertion reactions into the V−Cexobond of the pentafulvene complexes by multiple bond containing substrates were found for acetone, 4‐chlorobenzonitril andN,N’‐dicyclohexylcarbodiimide.