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|Section2= }} 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,〔Naffa, P.; Ourisson, G. ''Bulletin de la Société chimique de France'', 1954, 1410.〕 ''Pinus longifolia'' (obsolete name for ''Pinus roxburghii'' Sarg.)〔Simonsen, J. L. ''J. Chem. Soc.'' 1920, ''117'', 570.〕 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,〔Jadhav, P. K.; Brown, H. C. ''J. Org. Chem.'' 1981, ''46'', 2988.〕 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.〔(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) )〕 ==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, McMurray, Johnson,< Oppolzer, and Schultz. 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.〔Ho, Gregory ''J. Org. Chem.'' 2005, ''70'', 5139 -5143.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Longifolene」の詳細全文を読む スポンサード リンク
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