1,3,5-Hexatriene

1,3,5-Hexatriene
	trans-1,3,5-hexatriene
Identifiers
CAS Number	2235-12-3 mixture of cis and trans isomers; 821-07-8 E isomer; 2612-46-6 Z isomer;
3D model (JSmol)	Interactive image;
ECHA InfoCard	100.017.082
EC Number	218-789-7;
PubChem CID	145521;
CompTox Dashboard (EPA)	DTXSID3062283 ;
	InChI InChI=1S/C6H8/c1-3-5-6-4-2/h3,6H,1-2,5H2 Key: KHQKGRVDIZQGHT-UHFFFAOYSA-N;
	SMILES C=CCC=C=C;
Properties
Chemical formula	C6H8
Molar mass	80.130 g·mol−1
Appearance	yellow liquid
Boiling point	80–80.5 °C (176.0–176.9 °F; 353.1–353.6 K)
Refractive index (nD)	1.5103–1.5119
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

1,3,5-Hexatriene refers to a pair of organic compounds with the formula CH₂=CHCH=CHCH=CH₂. The compound is normally obtained as a mixture of cis- and trans-isomers.

Preparation

It can be prepared by several methods, an optimized procedure involves dehydration of 1,5-hexadiene-3-ol, which is obtained from allyl Grignard reagent and acrolein.^[1]

The compound has been off interest theoretically, e.g. the Woodward-Hoffmann Rules. 1,3-cyclohexadiene undergoes photoinduced conrotatory ring-opening to give 1,3,5-hexatriene.^[2]

Reactions

Protonation of 1,3,5-hexatriene gives the transient methylpentadienyl cation. It undergoes nitration, reminiscent of the behavior of benzene. With maleic anhydride, it undergoes Diels-Alder reaction.^[3]

Related compounds

Diphenylhexatriene
1,3,5,7-Octatetraene, a colorless solid, can be prepared by a related procedure involving pentadienal in place of acrolein.^[4]^[5]

References

^ Hwa, Jesse C. H.; Sims, Homer (1961). "1,3,5-Hexatriene". Organic Syntheses. 41: 49. doi:10.15227/orgsyn.041.0049.
^ Deb, Sanghamitra; Weber, Peter M. (2011). "The Ultrafast Pathway of Photon-Induced Electrocyclic Ring-Opening Reactions: The Case of 1,3-Cyclohexadiene". Annual Review of Physical Chemistry. 62: 19–39. doi:10.1146/annurev.physchem.012809.103350. PMID 21054174.
^ Woods, G. F.; Bolgiano, N. C.; Duggan, D. E. (1955). "The Chemistry of 1,3,5-Hexatriene". Journal of the American Chemical Society. 77 (7): 1800–1803. Bibcode:1955JAChS..77.1800W. doi:10.1021/ja01612a023.
^ Woods, G. Forrest.; Schwartzman, Louis H. (1949). "1,3,5,7-Octatetraene". Journal of the American Chemical Society. 71 (4): 1396–1399. doi:10.1021/ja01172a073.
^ Yoshida, H.; Tasumi, M. (1988). "Infrared and Raman spectra of trans,trans-1,3,5,7-octatetraene and normal-coordinate analysis based on ab initio molecular orbital calculations". The Journal of Chemical Physics. 89 (5): 2803–2809. doi:10.1063/1.454982.

[1] Hwa, Jesse C. H.; Sims, Homer (1961). "1,3,5-Hexatriene". Organic Syntheses. 41: 49. doi:10.15227/orgsyn.041.0049.

[2] Deb, Sanghamitra; Weber, Peter M. (2011). "The Ultrafast Pathway of Photon-Induced Electrocyclic Ring-Opening Reactions: The Case of 1,3-Cyclohexadiene". Annual Review of Physical Chemistry. 62: 19–39. doi:10.1146/annurev.physchem.012809.103350. PMID 21054174.

[3] Woods, G. F.; Bolgiano, N. C.; Duggan, D. E. (1955). "The Chemistry of 1,3,5-Hexatriene". Journal of the American Chemical Society. 77 (7): 1800–1803. Bibcode:1955JAChS..77.1800W. doi:10.1021/ja01612a023.

[4] Woods, G. Forrest.; Schwartzman, Louis H. (1949). "1,3,5,7-Octatetraene". Journal of the American Chemical Society. 71 (4): 1396–1399. doi:10.1021/ja01172a073.

[5] Yoshida, H.; Tasumi, M. (1988). "Infrared and Raman spectra of trans,trans-1,3,5,7-octatetraene and normal-coordinate analysis based on ab initio molecular orbital calculations". The Journal of Chemical Physics. 89 (5): 2803–2809. doi:10.1063/1.454982.

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