Di-tert-butylcyclopentadiene

Di-tert-butylcyclopentadiene
Identifiers
CAS Number	73046-16-9; 114987-03-0;
3D model (JSmol)	Interactive image;
ChemSpider	2835281;
PubChem CID	3599405;
CompTox Dashboard (EPA)	DTXSID70394029;
	InChI InChI=1S/C13H22/c1-12(2,3)10-7-8-11(9-10)13(4,5)6/h7-10H,1-6H3 Key: RADVPPBTEASJRZ-UHFFFAOYSA-N;
	SMILES CC(C)(C)C1C=CC(=C1)C(C)(C)C;
Properties
Chemical formula	C13H22
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). Infobox references

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

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

References

^ Hyster, Todd K. (2015). "1,3-Di-tert-butylcyclopentadiene". Encyclopedia of Reagents for Organic Synthesis: 1–2. doi:10.1002/047084289X.rn01866. ISBN 9780470842898.
^ 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.
^ 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.

[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.

[Walter-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.

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