Longifolene
From Wikipedia, the free encyclopedia
| (+)-Longifolene | |
|---|---|
 |
|
| IUPAC name | (1R,2S,7S,9S)-3,3,7-trimethyl -8-methylenetricyclo- [5.4.0.02,9]undecane |
| Identifiers | |
| CAS number | [475-20-7] |
| SMILES | C=C1C3(C)C2CC C1C2C(C)(C)CCC3 |
| Properties | |
| Molecular formula | C15H24 |
| Molar mass | 204.36 g/mol |
| Density | 0.928 g/cm3 |
| Boiling point |
254 °C (706 mm Hg) |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and 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 some primitive plants like fungi and liverworts.
Longifolene is used in organic synthesis for the preparation of dilongifolylborane,[3] a chiral hydroborating agent.
[edit] 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[4][5], McMurray[6], Johnson[7], Oppolzer[8], and Schultz[9].
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.[10]
[edit] 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.
[edit] 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.
- ^ Corey, E. J. et al. J. Am. Chem. Soc. 1961, 83, 1251.
- ^ Corey, E. J. et al. J. Am. Chem. Soc. 1964, 86, 478.
- ^ McMurray, J. E.; Isser, S. J. J. Am. Chem. Soc. 1972, 94, 7132.
- ^ Volkermann, R. A.; Andrews, G. C.; Johnson, W. S. J. Am. Chem. Soc. 1975, 97, 4777-4779.
- ^ Oppolzer, W.; Godel, T. J. Am. Chem. Soc. 1978, 100, 2584.
- ^ Schultz, A. G. et al. J. Org. Chem. 1985, 50, 915.
- ^ Ho, Gregory J. Org. Chem. 2005, 70, 5139 -5143.
- Dev, S. Acc. Chem. Res. 1981, 14, 82-88.
