The chemistry of the himachalenes and atlantones from Cedrus

Abstract

Synthesis and functionalization of natural products are useful procedures to access and develop new and interesting molecules with biological properties. In this review we discuss the major sesquiterpenes isolated from the essential oil of cedar, which represents a family of abundant and inexpensive natural materials. Some total synthesis and chemical transformations described in the literature have been included.

Chemical Modification of Biomarkers through Accelerated Degradation: Implications for Ancient Plant Identification in Archaeo-Organic Residues

“…The predominant compounds present in the fresh Cedrus atlantica oil were sesquiterpenes with the himachalene carbon skeleton generally found in the genus cedar [ 50 , 51 , 52 , 53 , 54 ], with the bicyclic sesquiterpene hydrocarbons α- γ- and β-himachalenes (#24, #29, #32) forming the largest peaks. Other constituents of the himachalane series, such as himachalene-1,4-diene (#30), α- and γ-dehydro-ar-himachalene (#33, #38), ar-himachalene (#39), oxidohimachalene (#47), (#55), and himachalol (#63) were detected in low amounts.…”

BF3·OEt2-Catalyzed Rearrangement of Epoxy-Himachalenes: Access to New Biosourced N-Acetamide-Based Himachalenes

“…513, 475 cm -1 . 3b,7,3b,4,5,6,7,7a,4] 3287, 3034, 2953, 2917, 1635, 1542, 1441, 1368, 1318, 1300, 1253, 1212, 1012, 790, 598, 536 cm -1 . N-{(1R,3aR,3bS,7aR,7bS)-1-Hydroxy-1,3b,7,7-tetramethyldecahydro-3aH-cyclopenta[3,4]cyclobuta[1,2]…”

“…This oil consists mainly of bicyclic sesquiterpene hydrocarbons, particularly 20% of -cis-and 50% -himachalene, respectively. 4 For sev-eral years, these sesquiterpenes have been the subject of research, especially their total synthesis 5 and their chemical transformation by different types of organic reactions such as gem-dihalogenocyclopropanation, alkene oxidation, halogenation addition, and hydrochlorination/dehydrohalogenation. [6][7][8] The epoxidation of himachalenes remains the most studied reaction since it provides new enantiomerically pure oxygenated compounds.…”

“…[6][7][8] The epoxidation of himachalenes remains the most studied reaction since it provides new enantiomerically pure oxygenated compounds. 5 The selective reactivity of both double bonds of -and -himachalenes in different reaction conditions (epoxidation, gem-cyclopropanation, oxidation, etc. ) is of some interest.…”

“…) is of some interest. 5 Indeed, epoxidation of -cis-and -himachalenes is stereo-and regioselective, the most substituted -side double bond being the most reactive. 4 In addition, the rearrangement of epoxides to carbonyl or nitrogen compounds represents an useful synthetic transformation, and hence several products could be obtained according to the nature of epoxides, catalysts, and reaction conditions.…”