Longifolene

Longifolene is a common sesquiterpene. It is an 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. It is a tricyclic chiral molecule. The enantiomer commonly found in pines and other higher plants exhibits a positive optical rotation of +42.73°. The other enantiomer is found in small amounts in certain fungi and liverworts.

Occurrence

Terpentine obtained from Pinus longifolia (obsolete name for Pinus roxburghii Sarg.) contains as much as 20% of longifolene. Longifolene is also one of two most abundant aroma constituents of lapsang souchong tea, because the tea is smoked over pinewood fires. ==Biosynthesis==

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. ==Synthesis and related chemistry==

Synthesis and related chemistry

The laboratory characterization and synthesis of longifolene has long attracted attention. It reacts with borane to give the derivative dilongifolylborane, which is a chiral hydroborating agent. ==References==

Source: Wikipedia ↗

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