Formation of a conjugated oxametallacyclohexadiene by dyotropic rearrangement of bis(2-furyl)zirconocene

Abstract

Bis(2-furyl)zirconocene (1), obtained from Cp₂ZrCl₂(Cp =η-cyclopentadienyl) and 2-furyl-lithium, cleanly undergoes dyotropic rearrangement at 185°C to yield the metallacyclic oxazirconacyclohexadiene derivative (2); complex (2) reacts with dimethyl acetylenedicarboxylate at 105°C in a Diels–Alder/retro-Diels–Alder reaction sequence to produce (Cp₂ZrO)₃ and dimethyl 3-(2-furyl)phthalate (4).