Longifolene
| Longifolene | |
| Names | |
|---|---|
| IUPAC name
(1R,2S,7S,9S)- 3,3,7-trimethyl- 8-methylenetricyclo- [5.4.0.02,9]undecane
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| Identifiers | |
475-20-7  |
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| ChEBI | CHEBI:49282  |
| ChemSpider | 1406720 |
| Jmol 3D model | Interactive image |
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| Properties | |
| C15H24 | |
| Molar mass | 204.36 g/mol |
| Density | 0.928 g/cm3 |
| Boiling point | 254 °C (489 °F; 527 K) (706 mm Hg) |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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 verify (what is ?) |
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| Infobox references | |
Longifolene is the common (or trivial) chemical name of a naturally occurring, oily liquid hydrocarbon found primarily in the high-boiling fraction of certain pine resins. The name is derived from that of a pine species from which the compound was isolated,[1] Pinus longifolia (obsolete name for Pinus roxburghii Sarg.)[2]
Chemically, longifolene is a tricyclic sesquiterpene. This molecule is chiral, and the enantiomer commonly found in pines and other higher plants exhibits a positive optical rotation of +42.73°. The other enantiomer (optical rotation −42.73°) is found in small amounts in certain fungi and liverworts.
Longifolene is used in organic synthesis for the preparation of dilongifolylborane,[3] a chiral hydroborating agent.
Longifolene is also one of two most abundant aroma constituents of lapsang souchong tea, because the tea is smoked over pine fires.[4]
Total syntheses
Due to the compact tricyclic structure and lack of functional groups, Longifolene is an attractive target for research groups highlighting new synthetic methodologies. Notable syntheses are by Corey,[5][6] McMurray,[7] Johnson,<[8] Oppolzer,[9] and Schultz.[10]
| Longifolene total synthesis by Corey.svg |
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The Johnson biosynthesis has since been validated as feasible using modern quantum mechanical computational methods. The subsequent cationic cascade mechanism has been shown to go through a non-classical cation intermediate.[11]
Biosynthesis
The biosynthesis of longifolene begins with farnesyl diphosphate (1) (also called farnesyl pyrophosphate) by means of a cationic polycyclization cascade. Loss of the pyrophosphate group and cyclization by the distal alkene gives intermediate 3, which by means of a 1,3-hydride shift gives intermediate 4. After two additional cyclizations, intermediate 6 produces longifolene by a 1,2-alkyl migration.
Use
The borane derivative dilongifolylborane is used in organic synthesis as a chiral hydroborating agent.[12]
External links
References
- ↑ Naffa, P.; Ourisson, G. Bulletin de la Société chimique de France, 1954, 1410.
- ↑ Simonsen, J. L. J. Chem. Soc. 1920, 117, 570.
- ↑ Jadhav, P. K.; Brown, H. C. J. Org. Chem. 1981, 46, 2988.
- ↑ Shan-Shan Yao； Wen-Fei Guo； YI Lu； Yuan-Xun Jiang, "Flavor Characteristics of Lapsang Souchong and Smoked Lapsang Souchong,a Special Chinese Black Tea with Pine Smoking Process", Journal of Agricultural and Food Chemistry, Vol. 53, No.22, (2005)
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- ↑ Ho, Gregory J. Org. Chem. 2005, 70, 5139 -5143.
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