Di-tert-butylcyclopentadiene is an organic compound with the formula (Me<sub>3</sub>C)<sub>2</sub>C<sub>5</sub>H<sub>4</sub>, where Me = methyl. It is a colorless liquid that is soluble in organic solvents. The compound is the conjugate acid of the di-tert-butylcyclopentadienyl ligand, (Me<sub>3</sub>C)<sub>2</sub>C<sub>5</sub>H<sub>3</sub><sup>âÂÂ</sup> (sometimes abbreviated Cp<sup>â¡âÂÂ</sup>). Two regioisomers of di-tert-butylcyclopentadiene exist, depending on the relative location of the double bonds.
Di-tert-butylcyclopentadiene is prepared by alkylation of cyclopentadiene with tert-butyl bromide under phase-transfer conditions.
It is the precursor to many metal complexes, such as the olefin polymerization catalyst ((Me<sub>3</sub>C)<sub>2</sub>C<sub>5</sub>H<sub>3</sub>)TiCl<sub>3</sub>.
The conjugate base of di-tert-butylcyclopentadiene reacts with a third equivalent of tert-butyl bromide to give (Me<sub>3</sub>C)<sub>3</sub>C<sub>5</sub>H<sub>3</sub>: