The direct oxidative diene cyclization and related reactions in natural product synthesis

• Juliane Adrian,
• Leona J. Gross and
• Christian B. W. Stark

Beilstein J. Org. Chem. 2016, 12, 2104–2123, doi:10.3762/bjoc.12.200

• considered in complement [4][5][6]. Oxidative cyclization – Historical background In 1924 Kötz and Steche reported on an investigation of the constitution of the monoterpene geraniol (1, R = H) [7]. Though the overall structure was known at that time, the position of one of the two C–C-double bonds within

Mechanistic investigations on six bacterial terpene cyclases

• Patrick Rabe,
• Thomas Schmitz and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2016, 12, 1839–1850, doi:10.3762/bjoc.12.173

• interesting molecular properties. Particularly obvious is their often characteristic aroma that contributes to the typical flavour of many essential oils from plants. This is exemplified by the monoterpene α-pinene that occurs in form of both enantiomers in pine trees, while (R)-(+)-limonene is found in

• much later, with the first described compounds being geosmin [3] and 2-methylisoborneol [4], two irregular terpenoids that represent a degraded sesquiterpene [5] and a methylated monoterpene [6], respectively. These compounds have a musty or earthy aroma and are responsible for the smell of freshly

Selective bromochlorination of a homoallylic alcohol for the total synthesis of (−)-anverene

• Frederick J. Seidl and
• Noah Z. Burns

Beilstein J. Org. Chem. 2016, 12, 1361–1365, doi:10.3762/bjoc.12.129

• homoallylic alcohol. Critical factors for optimization of this reaction are highlighted. The utility of the product bromochloride is demonstrated by the first total synthesis of an antibacterial polyhalogenated monoterpene, (−)-anverene. Keywords: enantioselective catalysis; halogenation; natural products

Efficient syntheses of climate relevant isoprene nitrates and (1R,5S)-(−)-myrtenol nitrate

• Sean P. Bew,
• Glyn D. Hiatt-Gipson,
• Graham P. Mills and
• Claire E. Reeves

Beilstein J. Org. Chem. 2016, 12, 1081–1095, doi:10.3762/bjoc.12.103

• monoterpene nitrate (1R,2S)-(−)-myrtenol nitrate. Keywords: atmospheric chemistry; exchange reaction; halide; isoprene nitrate; monoterpene; Introduction Understanding the chemistry of the biosphere and its interaction with the atmosphere is fundamental to Earth System science. Such is the importance of

• monoterpenes account for a large percentage of the total emissions that are not non-methane VOCs. Furthermore although monoterpene emissions (127 Tg C yr−1) are significant lower than isoprene [6] (viz. 600 Tg C yr−1) they are nonetheless gaining in significance and are now considered to be important

• to monoterpene derived O-nitrate ester synthesis was undertaken using (1R,5S)-(−)-myrtenol (84) which was quickly and efficiently converted into the corresponding optically active 1° alkyl bromide 85 which, due to its instability, was used ‘as is’ [55]. Employing our standard silver nitrate

A practical way to synthesize chiral fluoro-containing polyhydro-2H-chromenes from monoterpenoids

• Oksana S. Mikhalchenko,
• Dina V. Korchagina,
• Konstantin P. Volcho and
• Nariman F. Salakhutdinov

Beilstein J. Org. Chem. 2016, 12, 648–653, doi:10.3762/bjoc.12.64

• -fluorohexahydro-2H-chromenes under the developed conditions, the reaction occurs with inversion of configuration. Keywords: chirality; fluorine; halo-Prins reaction; isopulegol; monoterpene; Introduction Recently, we have found that a reaction between para-mentha-6,8-dien-2,3-diol (1) and aromatic aldehydes in

Thermal and oxidative stability of the Ocimum basilicum L. essential oil/β-cyclodextrin supramolecular system

• Daniel I. Hădărugă,
• Nicoleta G. Hădărugă,
• Corina I. Costescu,
• Ioan David and
• Alexandra T. Gruia

Beilstein J. Org. Chem. 2014, 10, 2809–2820, doi:10.3762/bjoc.10.298

• properties, and its antimicrobial [19] biological effects. Moreover, the anticancer potential of basil components has been studied [24]. These sensory and pharmaceutical properties of basil are primarily due to the presence of essential oil components, which consist of monoterpene hydrocarbons (e.g., β

• %) and methylchavicol (6) (19.6%), from oxygenated monoterpene and phenolic derivative compound classes, respectively. Limonene (1) was the most important component from the monoterpene class (0.5%), while other monoterpene derivatives in the O. basilicum L. essential oil were eucalyptol (2), camphor (5

Stereoselective synthesis of perillaldehyde-based chiral β-amino acid derivatives through conjugate addition of lithium amides

• Zsolt Szakonyi,
• Reijo Sillanpää and
• Ferenc Fülöp

Beilstein J. Org. Chem. 2014, 10, 2738–2742, doi:10.3762/bjoc.10.289

• addition was observed. Amino ester 11 was obtained as a single product and transformed to the corresponding amino acids 10A and 10D in good yields on the gram scale. Keywords: asymmetric synthesis; β-amino acid; chiral; Michael addition; monoterpene; Introduction In the past decade, cyclic β-amino acids

• ][34]. From this aspect, chiral, monoterpene-based α,β-unsaturated esters might be excellent starting materials, in which the natural monoterpene skeleton may serve as the chiral origin for the stereoselective construction of the β-amino acid moiety. Our present aim was the synthesis of new, limonene

Application of cyclic phosphonamide reagents in the total synthesis of natural products and biologically active molecules

• Thilo Focken and
• Stephen Hanessian

Beilstein J. Org. Chem. 2014, 10, 1848–1877, doi:10.3762/bjoc.10.195

• inflammation and traumatic bleeding. The leaves and stems of this plant contain oleoside-type secoiridoid glucosides with structurally interesting tetrasubstituted cyclopentanoid monoterpene units [116]. Two representative examples of these glycosides are nudifloside A (151) and D (13), which share a common

Selective allylic hydroxylation of acyclic terpenoids by CYP154E1 from Thermobifida fusca YX

• Anna M. Bogazkaya,
• Clemens J. von Bühler,
• Sebastian Kriening,
• Alexandrine Busch,
• Alexander Seifert,
• Jürgen Pleiss,
• Sabine Laschat and
• Vlada B. Urlacher

Beilstein J. Org. Chem. 2014, 10, 1347–1353, doi:10.3762/bjoc.10.137

• hydroxylation reactions leading to synthetically relevant intermediates [5][6][7][8][9][10][11]. In addition to chemical catalysts a range of enzymes has been studied for selective allylic hydroxylation of alkenes [12][13]. Among biosynthetic routes selective allylic hydroxylation of monoterpene olefines to

Isocyanide-based multicomponent reactions towards cyclic constrained peptidomimetics

• Gijs Koopmanschap,
• Eelco Ruijter and
• Romano V.A. Orru

Beilstein J. Org. Chem. 2014, 10, 544–598, doi:10.3762/bjoc.10.50

• -3CR-approach with enantiopure monoterpene-based β-amino acids [43] (19, Scheme 8), giving 22 as major isomer [44]. The stereoselectivity for 22 was explained by the steric effects of the dimethyl bridge that might prefer a Re-attack of the isocyanide. Compared to methanol, again the reaction in water

A new intermediate in the Prins reaction

• Shinichi Yamabe,
• Takeshi Fukuda and
• Shoko Yamazaki

Beilstein J. Org. Chem. 2013, 9, 476–485, doi:10.3762/bjoc.9.51

• produced when pinene (a bicyclic monoterpene) was heated with paraformaldehyde. However, Prins performed the first rather comprehensive study of the reactions between formaldehyde and hydrocarbons with C=C double bonds [2][3]. These were styrene, pinene, camphene and anethole. As a catalyst, sulfuric acid

Stereoselective synthesis of trans-fused iridoid lactones and their identification in the parasitoid wasp Alloxysta victrix, Part I: Dihydronepetalactones

• Nicole Zimmermann,
• Robert Hilgraf,
• Lutz Lehmann,
• Daniel Ibarra and
• Wittko Francke

Beilstein J. Org. Chem. 2012, 8, 1246–1255, doi:10.3762/bjoc.8.140

• analysis (GC/CIMS) showed the molecular mass of the compound to be M+ = 168, while high resolution mass spectrometry (GC/HRMS) proved its atomic composition to be C10H16O2, suggesting an oxygenated monoterpene as the target structure. The fragmentation pattern, exhibited in the 70 eV EI-mass spectrum