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3D model (JSmol)
  • InChI=1S/C13H22/c1-12(2,3)10-7-8-11(9-10)13(4,5)6/h7-10H,1-6H3
  • CC(C)(C)C1C=CC(=C1)C(C)(C)C
Molar mass 178.319 g·mol−1
Boiling point 100–105 °C (212–221 °F; 373–378 K) 30 torr
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Di-tert-butylcyclopentadiene is an organic compound with the formula (Me3C)2C5H4, 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, (Me3C)2C5H3}}[1] (sometimes abbreviated Cp). Two regioisomers of di-tert-butylcyclopentadiene exist, depending on the relative location of the double bonds.

Synthesis and reactions[edit]

Di-tert-butylcyclopentadiene is prepared by alkylation of cyclopentadiene with tert-butyl bromide under phase-transfer conditions.[2]

It is the precursor to many metal complexes, such as the olefin polymerization catalyst ((Me3C)2C5H3)TiCl3.[3]

The conjugate base of di-tert-butylcyclopentadiene reacts with a third equivalent of tert-butyl bromide to give (Me3C)3C5H3:

(Me3C)2C5H4 + NaH → Na(Me3C)3C5H3 + H2
Na(Me3C)2C5H3 + Me3CBr → (Me3C)3C5H3 + NaBr


  1. ^ Hyster, Todd K. (2015). "1,3-Di-tert-butylcyclopentadiene". Encyclopedia of Reagents for Organic Synthesis: 1–2. doi:10.1002/047084289X.rn01866. ISBN 9780470842898.
  2. ^ Reiners, Matthias; Ehrlich, Nico; Walter, Marc D. (2018). Synthesis of 1,3,5-Tri-tert-Butylcyclopenta-1,3-diene and Its Metal Complexes Na{1,2,4-(Me3C)3C5H2} and Mg{η5-1,2,4-(Me3C)3C5H2)2. Inorganic Syntheses. Vol. 37. p. 199. doi:10.1002/9781119477822.ch8. S2CID 105376454.
  3. ^ Nomura, Kotohiro; Naga, Naofumi; Miki, Misao; Yanagi, Kazunori; Imai, Akio (1998). "Synthesis of Various Nonbridged Titanium(IV) Cyclopentadienyl−Aryloxy Complexes of the Type Cp′Ti(OAr)X2 and Their Use in the Catalysis of Alkene Polymerization. Important Roles of Substituents on both Aryloxy and Cyclopentadienyl Groups". Organometallics. 17 (11): 2152–2154. doi:10.1021/OM980106R.