Preparation of 1,2,3,4-Tetramethylpentafulvene by Hydride Anion Abstraction from Lithium Pentamethylcyclopentadienide Employing Tritylchloride

A novel synthesis of 1,2,3,4-tetramethylpentafulvene based on hydride abstraction from pentamethylcyclopentadienide anion by means of trityl cation is described. Thus, Li[C₅Me₅)] (6) is treated with tritylchloride for 12 hours at 5°C in a toluene/THF solvent mixture (1:1), LiCl is then precipitated by treatment with pentane, and the co-product triphenylmethane is effectively removed by crystallization at -30°C. 1,2,3,4-Tetramethylpentafulvene is reliably obtained in >80% yield by this very simple method. The thus prepared fulvene was used for the synthesis of bis[η ⁵-(diarylphosphinomethyl)tetramethylcyclopentadienyl]ZrCl₂ complexes.

fulvene synthesis - hydride abstraction - metallocenes - organometallic reagents - cyclopentadienes - organometallic reagents - lithium