cas 123-35-3, Myrcene | Articles data

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Walker,Hawkins
p. 4209
(1952)
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Acid-catalyzed hydrolysis of alcohols and their β-D-glucopyranosides
The hydrolysis, in model wine at pH 3, of the allylic, homoallylic, and propargylic glycosides, geranylβ-D-glucopyranoside, [3'-(1'-cyclohexenyl)- 1'-methyl-2'-propynyl]-β-D-glucopyranoside, (3'RS,9'SR)(3'-hydroxy-5'- megastigmen-7-yn-9-yl)-β-D-glucopyranoside, (3',5',5'-trimethyl-3'- cyclohexenyl)-β-D-glucopyranoside, E-(7'-oxo-5',8'-megastigmadien-3'-yl)-β- D-glucopyranoside (3-hydroxy-β-damascone-β-D-glucopyranoside), and their corresponding aglycons has been studied. In general, aglycons were more rapidly converted to transformation products than were the corresponding glucosides. Glycoconjugation of geraniol in grapes is a process that reduces the flavor impact of this compound in wine, not only because geraniol is an important flavor component of some wines but also because the rate of formation of other flavor compounds from geraniol during bottle-aging is reduced. However, when flavor compounds such as β-damascenone are formed in competition with flavorless byproducts, such as 3-hydroxy-β-damascone, by acid-catalyzed hydrolytic reactions of polyols, then glycoconjugation is a process that could enhance as well as suppress the formation of flavor, depending on the position of glycosylation. (3'RS,9'SR)-(3'-Hydroxy-5'- megastigmen-7'-yn-9'-yl)-β-D-glucopyranoside hydrolyzed more slowly but gave a higher proportion of β-damascenone in the products than did the aglycon at 50 °C. Reaction temperature also effected the relative proportion of the hydrolysis products. Accelerated studies do not parallel natural processes precisely but only approximate them.
Skouroumounis, George K.,Sefton, Mark A.
p. 2033 - 2039
(2000)
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Palladium-Catalyzed Reactions of Allylic Electrophiles with Organometallic Reagents. A Regioselective 1,4-Elimination and a Regio- and Stereoselective Reduction of Allylic Derivatives
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Matsushita, Hajime,Negishi, Ei-ichi
p. 4161 - 4165
(1982)
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Yasuda,A. et al.
p. 1752 - 1756
(1979)
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Molybdenum- and tungsten-catalyzed allylation of aromatic compounds with allylic esters and alcohols
A novel method to substitute aromatic compounds with allylic groups using oxygen-containing allylic compounds in the presence of molybdenum or tungsten carbonyls under neutral conditions has been developed. The method is applicable to one step synthesis of methyl eugenol.
Shimizu, Isao,Sakamoto, Toshiaki,Kawaragi, Saeko,Maruyama, Yooichiro,Yamamoto, Akio
p. 137 - 138
(1997)
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Haley et al.
p. 264
(1969)
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Preparation of 1-Alkenes by the Palladium-Catalyzed Hydrogenolysis of Terminal Allylic Carbonates and Acetates with Formic Acid-Triethylamine
A useful method for the preparation of 1-alkenes from terminal allylic carbonates and acetates by the palladium-catalyzed reaction with formates is described.Formic acid-triethylamine is a suitable reductant.As catalyst, Pd2(dba)3CHCl3-P(n-Bu)3 gave the best result, 0.05-0.2 molpercent being sufficient (turnover 500-2000).Using this method, various 1-alkenes were prepared in good yields with high selectivity.
Tsuji, Jiro,Minami, Ichiro,Shimizu, Isao
p. 623 - 627
(1986)
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Selective Synthesis of 1,3-Dienic Terpenes in a β-Form through Regioselective 1,4-Elimination of Allylic Ethers
γ-Methyl-substituted allylic ethers proved to be converted into β-substituted dienes exclusively on treatment with t-BuOK in refluxing THF or cyclohexane.
Otera, Junzo,Niibo, Yoshihisa,Okuda, Kazuhiro
p. 1829 - 1832
(1986)
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Thermal behaviour of selected C10H16 monoterpenes
The presented work investigates the thermal behaviour of selected monoterpenes under various reactor temperatures and residence times (carrier gas, reactor inserts). In addition to the analysis of the liquid products by capillary GC and GC-MS, chemical derivatisation techniques (Diels-Alder reaction, hydrogenation) were used to identify the liquid-phase products. A thermal conversion of β-pinene (1), myrcene (2) and limonene (4) in a reaction network is presented and the experimental evidence for the formation of pyrolysis products by a biradical pathway is discussed. The reaction network was modified based on the identification of additional C10H 16 terpene isomers. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
Stolle, Achim,Brauns, Claudia,Nuechter, Matthias,Ondruschka, Bernd,Bonrath, Werner,Findeisen, Matthias
p. 3317 - 3325
(2006)
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Flash vacuum thermolysis of terpenic compounds in the pinane series
The flash pyrolysis of various derivatives (hydrocarbons and oxygenated compounds) in the pinane series has been studied. We observed a high degree of conversion and good selectivity.
Lemee,Ratier,Duboudin,Delmond
p. 1313 - 1318
(1995)
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Tanaka,S. et al.
p. 3252 - 3254
(1975)
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Liu,R.S.H.,Hammond,G.S.
p. 1892 - 1893
(1964)
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Hunt,Hawkins
p. 5618
(1950)
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Novel route to a fruitful mixture of terpene fragrances in particular phellandrene starting from natural feedstock geraniol using weak acidic boron based catalyst
Myrcene, ocimene and in particular phellandrene were selectively generated as products by dehydration of the natural feedstock geraniol over a weak acidic boron pentasil zeolite catalyst in a gas phase reaction. Additionally linalool was formed by rearrangement reaction. The total selectivity of these 4 terpenes is up to 99%.
Eisenacher, Matthias,Beschnitt, Stefan,H?lderich, Wolfgang
p. 214 - 217
(2012)
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Thermal behavior of pinan-2-ol and linalool
Linalool is an important intermediate for syntheses of isoprenoid fragrance compounds and vitamins A and E. One process option for its production is the thermal gas-phase isomerization of cis- and trans-pinan-2-ol. Investigations of this reaction were performed in a flow-type apparatus in a temperature range from 350-600 °C and a residence time range of 0.6-0.8 s. Rearrangement of the bicyclic alcohol led to linalool, plinols arising from consecutive reactions of linalool and other side products. Effects of residence time, temperature, surface-to-volume-ratio, carrier gas, and the presence of additives on yield and selectivity were studied. Furthermore, the effects of such parameters on ene-cyclization of linalool affording plinols were investigated. Results indicate that manipulation of the reaction in order to affect selectivity is difficult due to the large free path length to other molecules in the gas phase. However, conditions have been identified allowing one to increase the selectivity and the yield of linalool throughout pyrolysis of pinan-2-ol.
Leiner, Janne,Stolle, Achim,Ondruschka, Bernd,Netscher, Thomas,Bonrath, Werner
p. 8358 - 8375
(2013)
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Comparative thermolysis of β-and α-pinenes in supercritical ethanol: The reaction characterization and enantiomeric ratios of products
The thermolysis of β-pinene and the co-thermolysis of an equimolar mixture of β-and α-pinenes in supercritical ethanol were carried out. The reaction of β-pinene affords β-myrcene as the major product (>70%). Considerable differences in the temperature dependence of the reaction rate were revealed for the transformations of β-pinene into β-myrcene and of α-pinene into limonene. The pre-exponential factors and the activation energies were calculated. The enantiomeric ratios of the thermolysis products of β-and α-pinenes and limonene were estimated. The starting monoterpenes do not undergo racemization during thermolysis. The thermolysis of enantiomerically pure α-pinene affords racemic (±)-limonene, whereas (-)-β-pinene gives (-)-limonene. The enantiomeric ratio in the latter remains equal to the enantiomeric purity of the starting β-pinene.
Chibiryaev,Yermakova,Kozhevnikov,Sal'nikova,Anikeev
p. 1234 - 1238
(2007)
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Preparation method of myrcene
The method uses geraniol and/or nerol and/or linalool as a raw material, uses a palladium source and an organic phosphine as a catalyst to prepare myrcene, and realizes chemical synthesis of myrcene. The method has the advantages of high catalytic efficiency and high product selectivity.
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Paragraph 0033-0034

(2021/11/19)

A donor-acceptor complex enables the synthesis of: E -olefins from alcohols, amines and carboxylic acids
Olefins are prevalent substrates and functionalities. The synthesis of olefins from readily available starting materials such as alcohols, amines and carboxylic acids is of great significance to address the sustainability concerns in organic synthesis. Metallaphotoredox-catalyzed defunctionalizations were reported to achieve such transformations under mild conditions. However, all these valuable strategies require a transition metal catalyst, a ligand or an expensive photocatalyst, with the challenges of controlling the region- and stereoselectivities remaining. Herein, we present a fundamentally distinct strategy enabled by electron donor-acceptor (EDA) complexes, for the selective synthesis of olefins from these simple and easily available starting materials. The conversions took place via photoactivation of the EDA complexes of the activated substrates with alkali salts, followed by hydrogen atom elimination from in situ generated alkyl radicals. This method is operationally simple and straightforward and free of photocatalysts and transition-metals, and shows high regio- and stereoselectivities.
Chen, Kun-Quan,Shen, Jie,Wang, Zhi-Xiang,Chen, Xiang-Yu
p. 6684 - 6690
(2021/05/31)

Method and Means for Releasing a Terpene Mixture to a Cannabis Flower During Storage
A method and means for releasing a terpene mixture to a Cannabis flower during storage with may be from a cotton pulp card or a two-way humidity pack with an additional terpene blend for keeping a Cannabis flower fresh while naturally increasing the desired terpene levels. The product is a blend of humidity regulating agents infused with terpenes (plant derived) which allows for the product to be paired with herbal material to increase and maintain the relative humidity, while transferring the flavor/aroma/taste terpenes from the package into the herbal material. There are two embodiments, the first is a Terp Pack+Humidity (“Terp Pack+RH”) which contains a herban material to increase and maintain relative humidity, while releasing the infused terenes, and the second is more simply a Terp Pack (“Terp Pack”) which contains no humidity enhancing material and is only a carrier for releasing the terpene mixture.
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(2021/09/17)

Method for synthesizing high-purity 13C2-myrcene from 13C2-geraniol
The invention relates to a method for synthesizing high-purity 13C2-myrcene from 13C2-geraniol. The method comprises the following steps: (1) dissolving 13C2-geraniol in an organic solvent, adding hydrogen peroxide and p-toluenesulfonic acid monohydrate, stirring for reaction, monitoring the reaction process by TLC (Thin Layer Chromatography), after the reaction is completed, concentrating the obtained reaction solution under reduced pressure, and purifying by silica gel column chromatography to obtain an intermediate, (2) dissolving the intermediate in an organic solvent, stirring and heatingto react with potassium tert-butoxide and 18-crown ether-6 dissolved in an organic solvent under the protection of nitrogen, by TLC, monitoring the reaction process, after the reaction is completed,stirring and cooling the obtained reaction liquid, adding diethyl ether for extraction, sequentially cleaning an organic phase with water, a saturated sodium bicarbonate aqueous solution and saturatededible salt water, carrying out drying, and carrying out silica gel column chromatography purification so that high-purity 13C2-myrcene is obtained. According to the method, no metal catalyst or additive is used, the process conditions are mild, and the method has the advantages of being simple, efficient, economical and environmentally friendly and is particularly suitable for synthesis of isotope 13C or 14C labeled myrcene and non-isotope labeled myrcene.
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(2020/08/06)

Cationic Co(I)-intermediates for hydrofunctionalization reactions: Regio- A nd enantioselective cobalt-catalyzed 1,2-hydroboration of 1,3-dienes
Much of the recent work on catalytic hydroboration of alkenes has focused on simple alkenes and styrene derivatives with few examples of reactions of 1,3-dienes, which have been reported to undergo mostly 1,4-additions to give allylic boronates. We find that reduced cobalt catalysts generated from 1,n-bis-diphenylphosphinoalkane complexes [Ph2P-(CH2)n-PPh2]CoX2; n = 1-5) or from (2-oxazolinyl)phenyldiarylphosphine complexes [(G-PHOX)CoX2] (G = 4-substituent on oxazoline ring) effect selective 1,2-, 1,4-, or 4,3-additions of pinacolborane (HBPin) to a variety of 1,3-dienes depending on the ligands chosen. Conditions have been found to optimize the 1,2-additions. The reactive catalysts can be generated from the cobalt(II)-complexes using trimethylaluminum, methyl aluminoxane, or activated zinc in the presence of sodium tetrakis[(3,5-trifluoromethyl)phenyl]borate (NaBARF). The complex, (dppp)CoCl2, gives the best results (ratio of 1,2-to 1,4-addition >95:5) for a variety of linear terminal 1,3-dienes and 2-substituted 1,3-dienes. The [(PHOX)CoX2] (X = Cl, Br) complexes give mostly 1,4-addition with linear unsubstituted 1,3-dienes, but, surprisingly, selective 1,2-additions with 2-substituted or 2,3-disubstituted 1,3-dienes. Isolated and fully characterized (X-ray crystallography) Co(I)-complexes, (dppp)3Co2Cl2 and [(S,S)-BDPP]3Co2Cl2, do not catalyze the reaction unless activated by a Lewis acid or NaBARF, suggesting a key role for a cationic Co(I) species in the catalytic cycle. Regio- A nd enantioselective 1,2-hydroborations of 2-substituted 1,3-dienes are best accomplished using a catalyst prepared via activation of a chiral phosphinooxazoline-cobalt(II) complex with zinc and NaBARF. A number of common functional groups, among them,-OBn,-OTBS,-OTs, N-phthalimido-groups, are tolerated, and er's > 95:5 are obtained for several dienes including 1-alkenylcycloalk-1-enes. This operationally simple reaction expands the realm of asymmetric hydroboration to provide direct access to a number of nearly enantiopure homoallylic boronates, which are not readily accessible by current methods. The resulting boronates have been converted into the corresponding alcohols, potassium trifluororoborate salts, N-BOC amines, and aryl derivatives by C-BPin to C-aryl transformation.
Duvvuri, Krishnaja,Dewese, Kendra R.,Parsutkar, Mahesh M.,Jing, Stanley M.,Mehta, Milauni M.,Gallucci, Judith C.,Rajanbabu
supporting information
p. 7365 - 7375
(2019/05/16)

SnCl2-catalyzed synthesis of carbamates from renewable origin alcohols
Effects of structure and reactivity of renewable origin alcohols in the conversion and selectivity of the SnCl2-catalyzed reactions in the presence and absence of urea were assessed. Convenient simple and suitable method for the synthesis of carbamates from renewable origin alcohols and urea in one-step are provided. We have assessed the activity of SnCl2 catalyst, a commercially affordable Lewis acid, in reactions of urea alcoholysis with different natural origin alcohols (geranyl, neryl, bornyl, cinnamyl, α-terpinyl and benzyl alcohols), aiming to synthesize carbamates, which are biologically active compounds, building blocks in organic synthesis and raw material to synthesize polyurethanes. The low cost of urea, the water tolerant catalyst and phosgene free reaction are positive aspects of this carbamates synthesis process. The different reaction pathways were assessed. A mechanism was proposed based on FT-IR experiments and experimental data.
da Silva, Márcio José,Chaves, Diego Morais
p. 1169 - 1180
(2019/01/28)

Structural and functional insights into asymmetric enzymatic dehydration of alkenols
The asymmetric dehydration of alcohols is an important process for the direct synthesis of alkenes. We report the structure and substrate specificity of the bifunctional linalool dehydratase isomerase (LinD) from the bacterium Castellaniella defragrans that catalyzes in nature the hydration of β-myrcene to linalool and the subsequent isomerization to geraniol. Enzymatic kinetic resolutions of truncated and elongated aromatic and aliphatic tertiary alcohols (C5-C15) that contain a specific signature motif demonstrate the broad substrate specificity of LinD. The three-dimensional structure of LinD from Castellaniella defragrans revealed a pentamer with active sites at the protomer interfaces. Furthermore, the structure of LinD in complex with the product geraniol provides initial mechanistic insights into this bifunctional enzyme. Site-directed mutagenesis confirmed active site amino acid residues essential for its dehydration and isomerization activity. These structural and mechanistic insights facilitate the development of hydrating catalysts, enriching the toolbox for novel bond-forming biocatalysis.
Nestl, Bettina M.,Geinitz, Christopher,Popa, Stephanie,Rizek, Sari,Haselbeck, Robert J.,Stephen, Rosary,Noble, Michael A.,Fischer, Max-Philipp,Ralph, Erik C.,Hau, Hoi Ting,Man, Henry,Omar, Muhiadin,Turkenburg, Johan P,Van Dien, Stephen,Culler, Stephanie J.,Grogan, Gideon,Hauer, Bernhard
p. 275 - 281
(2017/02/23)

Sodium Diisopropylamide in Tetrahydrofuran: Selectivities, Rates, and Mechanisms of Alkene Isomerizations and Diene Metalations
Sodium diisopropylamide in tetrahydrofuran is an effective base for the metalation of 1,4-dienes and isomerization of alkenes. Dienes metalate via tetrasolvated sodium amide monomers, whereas 1-pentene is isomerized by trisolvated monomers. Facile, highly Z-selective isomerizations are observed for allyl ethers under conditions that compare favorably to those of existing protocols. The selectivity is independent of the substituents on the allyl ethers; rate and computational data show that the rates, mechanisms, and roles of sodium-oxygen contacts are substituent-dependent. The competing influences of substrate coordination and solvent coordination to sodium are discussed.
Algera, Russell F.,Ma, Yun,Collum, David B.
supporting information
p. 11544 - 11549
(2017/08/30)

A general and efficient method for the palladium-catalysed conversion of allylic alcohols into their corresponding dienes
A general method was established, converting a broad range of allylic alcohols directly and quantitatively into their corresponding dienes. The developed protocol allows the direct use of allylic alcohols, circumventing the need for their derivatisation into more reactive precursors, thereby minimising waste production with water as the sole co-product.
Ostrowski, Karoline A.,Vogelsang, Dennis,Vorholt, Andreas J.
p. 1302 - 1305
(2016/03/09)

Method for preparing ambrotone
The invention relates to a method for preparing ambrotone. The method includes steps of 1, synthesizing 3-methyl-3-pentene-2-ketone; 2, carrying out diene addition for preparing ambrotone intermediates; 3, carrying out cyclization reaction to prepare the ambrotone. Diene addition for preparing the ambrotone intermediates is carried out without catalysts by the aid of high-temperature gas-phase reaction. The method has the advantages that the ambrotone is prepared from raw materials beta-pinene, butanone and acetaldehyde, other organic solvents are omitted, high-pollution and high-carcinogenesis substances such as benzene and toluene are omitted, accordingly, the cost can be lowered, the quality of products can be effectively improved, the application range of the products can be effectively expanded, and Diels-Alder condensation reaction is carried out by the aid of the high-temperature gas-phase reaction; the Diels-Alder condensation reaction is carried out by the aid of the high-temperature gas-phase reaction or atomized small-molecule water drop and gas phases, catalysts such as Lewis acid or proton acid are omitted at reaction steps, accordingly, the production cost can be lowered, technological equipment can be simplified, post-reaction treatment working procedures can be shortened, and the purpose of zero sewage discharge can be truly achieved.
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Paragraph 0077; 0079; 0082; 0085; 0088; 0092

(2017/09/12)

Mutant polypeptides and uses thereof
The present disclosure provides novel polypeptides with 3-buten-2-ol dehydratase activity, polypeptides with catalytic activity in the conversion of 3-methyl-3-buten-2-ol to isoprene, and crystal structure data for one of such polypeptides. Methods of making and using the polypeptides and their related crystal structure data are also provided.
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Page/Page column 43

(2016/01/25)

Isotope sensitive branching and kinetic isotope effects to analyse multiproduct terpenoid synthases from Zea mays
Multiproduct terpene synthases TPS4-B73 and TPS5-Delprim from Zea mays exhibit isotopically sensitive branching in the formation of mono- and sesquiterpene volatiles. The impact of the kinetic isotope effects and the stabilization of the reactive intermediates by hyperconjugation along with the shift of products from alkenes to alcohols are discussed.
Gatto, Nathalie,Vattekkatte, Abith,K?llner, Tobias,Degenhardt, J?rg,Gershenzon, Jonathan,Boland, Wilhelm
supporting information
p. 3797 - 3800
(2015/03/30)

Ring-Opening Reactions of α- And β-Pinenes in Pressurized Hot Water in the Absence of Any Additive
Reactions of α- and β-pinenes in pressurized hot water were examined in a batch reactor made of a SS316 1/2-in. tube at temperatures of 250-400 C, pressures of 4-30 MPa, and reaction times of 1-30 min in the absence of any additive under an argon atmosphere. The maximum yields of limonene from α-pinene were ca. 70% in 20 min at 300 C or 1 min at 400 C. Limonene was obtained from β-pinene in ca. 16% yield for 30 min at 300 C and 1 min at 400 C. Reversible production of myrcene in 14% yield and formation of unidentified C20 dimer fractions were noted for 1 min at 370 C from β-pinene. The conversion of α-pinene to limonene took place under anhydrous conditions, albeit at slightly lower yield of 65% compared to processes conducted in the presence of water, where increased limonene yield of 70% was observed for 1 min at 400 C. The conversion of β-pinene to limonene under anhydrous conditions was limited to 6.1% in contrast to 11.9% in the presence of water for 7 min at 370 C. In the presence of oxygen, p-cymene was formed in 23% and 24% yield at the expense of limonene from α- and β-pinenes, respectively, for 30 min at 400 C.
Kawahara, Tomomi,Henmi, Yui,Onda, Natsu,Sato, Toshiyuki,Kawai-Nakamura, Akiko,Sue, Kiwamu,Iwamura, Hiizu,Hiaki, Toshihiko
supporting information
p. 1485 - 1491
(2014/01/06)

A 1,6-ring closure mechanism for (+)-δ-cadinene synthase?
Recombinant (+)-δ-cadinene synthase (DCS) from Gossypium arboreum catalyzes the metal-dependent cyclization of (E,E)-farnesyl diphosphate (FDP) to the cadinane sesquiterpene δ-cadinene, the parent hydrocarbon of cotton phytoalexins such as gossypol. In contrast to some other sesquiterpene cyclases, DCS carries out this transformation with >98% fidelity but, as a consequence, leaves no mechanistic traces of its mode of action. The formation of (+)-δ-cadinene has been shown to occur via the enzyme-bound intermediate (3R)-nerolidyl diphosphate (NDP), which in turn has been postulated to be converted to cis-germacradienyl cation after a 1,10-cyclization. A subsequent 1,3-hydride shift would then relocate the carbocation within the transient macrocycle to expedite a second cyclization that yields the cadinenyl cation with the correct cis stereochemistry found in (+)-δ-cadinene. An elegant 1,10-mechanistic pathway that avoids the formation of (3R)-NDP has also been suggested. In this alternative scenario, the final cadinenyl cation is proposed to be formed through the intermediacy of trans, trans-germacradienyl cation and germacrene D. In addition, an alternative 1,6-ring closure mechanism via the bisabolyl cation has previously been envisioned. We report here a detailed investigation of the catalytic mechanism of DCS using a variety of mechanistic probes including, among others, deuterated and fluorinated FDPs. Farnesyl diphosphate analogues with fluorine at C2 and C10 acted as inhibitors of DCS, but intriguingly, after prolonged overnight incubations, they yielded 2F-germacrene(s) and a 10F-humulene, respectively. The observed 1,10-, and to a lesser extent, 1,11-cyclization activity of DCS with these fluorinated substrates is consistent with the postulated macrocyclization mechanism(s) en route to (+)-δ-cadinene. On the other hand, mechanistic results from incubations of DCS with 6F-FPP, (2Z,6E)-FDP, neryl diphosphate, 6,7-dihydro-FDP, and NDP seem to be in better agreement with the potential involvement of the alternative biosynthetic 1,6-ring closure pathway. In particular, the strong inhibition of DCS by 6F-FDP, coupled to the exclusive bisabolyl- and terpinyl-derived product profiles observed for the DCS-catalyzed turnover of (2Z,6E)-farnesyl and neryl diphosphates, suggested the intermediacy of α-bisabolyl cation. DCS incubations with enantiomerically pure [1- 2H1](1R)-FDP revealed that the putative bisabolyl-derived 1,6-pathway proceeds through (3R)-nerolidyl diphosphate (NDP), is consistent with previous deuterium-labeling studies, and accounts for the cis stereochemistry characteristic of cadinenyl-derived sesquiterpenes. While the results reported here do not unambiguously rule in favor of 1,6- or 1,10-cyclization, they demonstrate the mechanistic versatility inherent to DCS and highlight the possible existence of multiple mechanistic pathways.
Faraldos, Juan A.,Miller, David J.,Gonzalez, Veronica,Yoosuf-Aly, Zulfa,Cascon, Oscar,Li, Amang,Allemann, Rudolf K.
supporting information; experimental part
p. 5900 - 5908
(2012/05/07)

Cyclization of citronellal in a supercritical solvent in a flow reactor in the presence of Al2O3
The reactivity of citronellal under supercritical solvent conditions in a flow reactor in the presence of Al2O3 is examined. It is shown that at 160°C, the main transformation product of citronellal is isopulegol, and when the temperature is increased to 190°C, they are monoterpenes with a para-menthane framework and myrcene. Pleiades Publishing, Ltd., 2012.
Anikeev,Il'Ina,Volcho,Salakhutdinov
p. 1917 - 1919
(2013/01/15)

Enantioselective construction of all-carbon quaternary centers by branch-selective Pd-catalyzed allyl-allyl cross-coupling
The Pd-catalyzed cross-coupling of racemic tertiary allylic carbonates and allylboronates is described. This reaction generates all-carbon quaternary centers in a highly regioselective and enantioselective fashion. The outcome of these reactions is consistent with a process that proceeds by way of 3,3′-reductive elimination of bis(η1-allyl)palladium intermediates. Strategies for distinguishing the product alkenes and application to the synthesis of (+)-α-cuparenone are also described.
Zhang, Ping,Le, Hai,Kyne, Robert E.,Morken, James P.
supporting information; experimental part
p. 9716 - 9719
(2011/08/04)

Kinetics of thermal conversions of monoterpenic compounds in supercritical lower alcohols
The most important information concerning thermal conversions of vegetable terpenes (α-pinene, β-pinene, turpentine, and cis-verbenol) in supercritical lower alcohols is systematized. The kinetics of selected reactions is reported and is compared with the kinetics of the same reactions in the gas and liquid phases. Thermodynamic calculations of the phase states and kinetic parameters are presented for a number of multicomponent multiphase systems containing terpenes and lower alcohols. The effect of the supercritical solvent pressure on the rate and selectivity of the selected reactions is reported.
Anikeev,Ermakova,Chibiryaev,Kozhevnikov
scheme or table
p. 162 - 193
(2010/09/04)

Linalool dehydratase-isomerase, a bifunctional enzyme in the anaerobic degradation of monoterpenes
Castellaniella (ex Alcaligenes) defragrans strain 65Phen mineralizes monoterpenes in the absence of oxygen. Soluble cell extracts anaerobically catalyzed the isomerization of geraniol to linalool and the dehydration of linalool to myrcene. The linalool dehydratase was present in cells grown on monoterpenes, but not if grown on acetate. We purified the novel enzyme ～1800-fold to complete homogeneity. The native enzyme had a molecular mass of 160 kDa. Denaturing gel electrophoresis revealed one single protein band with a molecular mass of 40 kDa, which indicated a homotetramer as native conformation. The aerobically purified enzyme was anaerobically activated in the presence of 2 mM DTT. The linalool dehydratase catalyzed in vitro two reactions in both directions depending on the thermodynamic driving forces: a water secession from the tertiary alcohol linalool to the corresponding acyclic monoterpene myrcene and an isomerization of the primary allylalcohol geraniol in its stereoisomer linalool. The specific activities (Vmax) were 140 nanokatals mg-1 for the linalool dehydratase and 410 nanokatals mg-1 for the geraniol isomerase, with apparent Km values of 750 μM and 500 μM, respectively. The corresponding open reading frame was identified and revealed a precursor protein with a signal peptide for a periplasmatic location. The amino acid sequence did not affiliate with any described enzymes. We suggest naming the enzyme linalool dehydratase-isomerase according to its bifunctionality and placing it as a member of a new protein family within the hydrolyases (EC 4.2.1.X).
Brodkorb, Danny,Gottschall, Matthias,Marmulla, Robert,Lueddeke, Frauke,Harder, Jens
experimental part
p. 30436 - 30442
(2011/11/12)

Comprehensive kinetic and mechanistic considerations for the gas-phase behaviour of pinane-type compounds
The thermal behaviour of selected pinane-type compounds, α-pinene (1), β-pinene (2), pinane (3) and nopinone (4), has been investigated. The conversion of the bicyclic starting materials to their acyclic and monocyclic isomers as well as the consecutive reactions of the acyclic main isomerisation products are discussed. The conversion of 1-4 in a reaction network is presented and the experimental evidence for the formation of pyrolysis products by a biradical pathway is discussed. In addition to these results a kinetic model describing the isomerisation of the bicyclic compounds to their acyclic and monocyclic isomers is presented. A good correlation between kinetic simulations and experimental data is revealed. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
Stolle, Achim,Ondruschka, Bernd,Bonrath, Werner
p. 2310 - 2317
(2008/02/08)

Zeolite Assisted Dehydration of Terpenic Alcohols : Convenient Synthesis of 1,3-Dienes and Oxepane
Terpenic alcohols undergo facile dehydration over H-ZSM-5 to yield 1,3-dienes, such as farnesenes, ocimene, myrcene and isoprene. Studies on homoallylic alcohol (1e) gave oxepane (2e).
Reddy, P. Veera,Bhat, Sujata V.
p. 688 - 689
(2007/10/03)

Cis-1,4-poly-β-myrcene; The structure of the polymeric fraction of mastic resin (Pistacia lentiscus L.) elucidated
The polymer fraction of mastic resin from Pistacia lentiscus L. was isolated and purified by extraction and Size Exclusion Chromatography. The molecular weight distribution of the polymer was broad and stretched up to 100,000 Da. The structure was characterised as 1,4-poly-β-myrcene, predominantly present in the cis-conformation. The compound is the first known example of a naturally occurring polymer of a monoterpene.
Van Den Berg, Klaas Jan,Van Der Horst, Jerre,Boon, Jaap J.,Sudmeijer, Olof O.
p. 2645 - 2648
(2007/10/03)

Medium- and sensitizer-dependent radical cation reactions: Deprotonation in fluid solution and solid matrices
Radical cations generated by photo-induced electron transfer in solution or by chemical oxidation in the channels of a redox-active zeolite (NaZSM-5) may be deprotonated, giving rise to neutral radicals. In solution, the geminate radical anion or an added nucleophile (methanol) may serve as the proton acceptor. Deprotonations in solution are not efficient; the corresponding products may be suppressed by several competing intra- or bi-molecular reactions. Although methanol serves as the base deprotonating at least one radical cation, it often is more efficient as a nucleophile, thereby depressing deprotonation. Deprotonations in the zeolite are more effective, presumably, because competing reactions with outside reagents are precluded. Occasionally, NaZSM-5 zeolites promote complex reaction sequences, such as the conversion of p-propylanisole to the radical cation of anethole or the deprotonation-ring opening of 1,2-diphenylcyclopropane radical cation to exo,exo-diphenylallyl radical. Acta Chemica Scandinavica 1997.
Roth, Heinz D.,Weng, Hengxin,Zhou, Dahui,Lakkaraju, Prasad S.
p. 626 - 635
(2007/10/03)

NORBORNENE COMPOUNDS HAVING CHAIN POLYENE GROUPS AND UNSATURATED ETHYLENIC COPOLYMER PRODUCED WITH THE USE OF THE SAME
The chain polyene-group containing norbornene compound of the invention is represented by the formula [I]: wherein n is an integer of 1 to 5, R1is an alkyl group of 1 to 5 carbon atoms, and R2and R3are each independently a hydrogen atom or an alkyl group of 1 to 5 carbon atoms. The unsaturated ethylene copolymer of the invention is a random copolymer of 30 to 92 % by mol of (i) ethylene units, 6 to 70 % by mol of (ii) specific α-olefin units and 0.1 to 30 % by mol of (iii) units derived from the norbornene compound [I], where the molar ratio of (i)/(ii) is in the range of 40/60 to 92/8 and the unit (iii) is represented by the specific formula, and has an intrinsic viscosity [η] of 0.05 to 10 dl/g. The novel unsaturated ethylene copolymer is excellent in weathering resistance, heat resistance and ozone resistance and has a high vulcanizing rate.
-
(2008/06/13)

Evidence for a cyclic mechanism in (η3-allyl)palladium chemistry. Promotion of β-hydride elimination by unsaturated organometallics
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Keinan, Ehud,Kumar, Sandeep,Dangur, Vered,Vaya, Jacob
p. 11151 - 11152
(2007/10/02)

ON THE DIRECT METALATION OF ISOPRENE
Isoprene has been metalated in tetrahydrofuran with an excess of sterically hindered potassium dialkylamides, prepared by combining equimolar amounts of the corresponding lithium amide and potassium tert-butoxide.Subsequent reaction with oxirane, alkyl bromides, and pivaldehyde gave the expected coupling products in reasonable yields.Coupling with (CH3)2CHCH2CH=O and (CH3)2C=CHCH=O afforded the bark beetle pheromones (+/-)-ipsenol and (+/-)-ipsdienol in low yields.
Klusener, P. A. A.,Tip, L.,Brandsma, L.
p. 2041 - 2064
(2007/10/02)

Mixed metal bases as promoters of 1,4-eliminations
When treated with the LIDAKOR mixture, allyl type ethers very readily undergo 1,4-elimination to afford conjugated dienes (3 - 73). In typical cases, the reaction is brought about stereo- and regioselectively (2 and 7, respectively). Under suitable conditions, lithium dimethylamide or even lithium diisopropylamide adds to the dienes generated in situ thus leading to a variety of new allyl amines (5-8).
Margot, Christian,Matsuda, Hiroyuki,Schlosser, Manfred
p. 2425 - 2430
(2007/10/02)

Facile Synthesis of Trifluoromethyl Ketones by Palladium-Catalyzed Carroll Type Reaction
Distannoxane-catalyzed transesterification of ethyl 4,4,4-trifluoroacetoacetate with allylic alcohols gave the corresponding allylic esters, which were subjected to palladium-catalyzed decarboxylation-allylation to give trifluoromethyl ketones.
Shimizu, Isao,Ishii, Hirotoshi,Tasaka, Atsuma
p. 1127 - 1128
(2007/10/02)

Potassium Carboxylates by Direct Carbonylation of Potassium Alkoxides
Reaction of the K+ alkoxide of linalool (1) in benzene with CO at 425-440 bar and 120-130 degC for 12-30 h gave the K+ salt of 2,6-dimethyl-2-vinyl-5-heptenoic acid (4a) in a ca. 25percent yield based on ca. 65percent converted alkoxide.Reaction of the + 18-crown-6> alkoxide of 1 with CO at 50-55 bar and 40 degC for 90-140 h gave a mixture containing mainly the + 18-c-6> salts of 4a (ca. 62percent) and of the homogeranic acids 3a and 6a (together ca. 27percent of the mixture) in a ca. 35percent combined yield based on 50-60percent converted alkoxide.The uncomplexed or complexed K+ alkoxide of (S)-1 gave, with ca. 85percent net retention, the K+ salt of (S)-4a.Reaction of the + 18-c-6> alkoxide of geraniol (2) with CO at 50 bar and 40 degC for 65-70 h gave myrcene (10) and geranyl formate (11) in a ca. 40-50percent yield each based on ca. 85percent converted alkoxide.Reaction of the + 18-c-6> alkoxide of 3-pentyl-1,4-pentadien-3-ol (14) at 50 bar and r.t. for 70 h gave a mixture of the + 18-c-6> salts of 2-pentyl-2-vinyl-3-butenoic acid (15a) (67percent) and the 4-pentyl-2,4-hexadienoic acids 18a and l9a (together 23percent of the mixture) in a ca. 90percent combined yield based on ca. 65percent converted alkoxide.
Rautenstrauch, Valentin
p. 593 - 599
(2007/10/02)

Hydrolysis od Bismetallic Complexes of Linalyldiphosphate and their Participation in the Biosynthesis of Cyclic Monoterpenes
The allylic diphosphate ester linalyldiphosphate forms mono- and bis-metallic complexes with Mg(2+) and Mn(2+).Complexes of the trianion of the ligand are 50 to 100 times more stable than those of the dianion.Mg(2+) and Mn(2+) are bound in the monometallic complex 1E3 and 1E4 times more strongly than in the bismetallic species.The rate constant of the uncatalysed hydrolysis of linalyldiphosphate at pH 7.0 is 1.2 x E4 s-1, which is higher than reported values for the primary diphosphates.Mg(2+) and Mn(2+) affect its rate of hydrolysis and it is shown that the rate enhancement observed is a function of the concentration of the bismetallic complexes.The rate of cyclic terpene hydrocarbon biosynthesis catalysed by carbocyclase from Citrus limonum also correlates with the concentration of the bismetallic complexes.Linalyl monophosphate, which is not a substrate for carbocyclase hydrolyses at a rate proportional to the concentration of the monometallic complex of Mn(2+).The neutral charge of this complex, as opposed to the positively charged bismetallic complex of linalyl diphosphate may be an explanation of the absence of utilization of this complex as a substrate.It appears from the data presented and from previous evidence that bismetallic complexes of allylic diphosphates are the most reactive species in their hydrolysis and the only reactive species in the enzymic cyclizaton of these precursors of monoterpenes.
Portilla, Gloria,Rojas, M. Cecilia,Chiong, Evaristo,Cori, Osvaldo
p. 1479 - 1484
(2007/10/02)

Photochemical Transformations VI: Organic Iodides (Part 5) - Templet Effect of Transition Metal Ions on Photocyclization of Some Olefinic Acyclic Terpene Iodides
Photocyclization of citronellyl iodide in the presence of certain transition metal salts especially CuCl, results in a significant increase (from 16percent to 35percent) in the yield of the cyclization products.Similar results have been obtained with geranyl and neryl iodides (11, 17).This enhancement of cyclization/elimination ratio is sought to be explained in terms of a templet effect of the transition metal ion.
Subbarao, Kanury V.,Damodaran, N. P.,Dev, Sukh
p. 1008 - 1011
(2007/10/02)

2-Allylisourea as an Effective Agent for Direct α-Allylation of Ketone and Aldehyde Assisted by Palladium(0) under Neutral Conditions
Direct α-allylation of a variety of ketones and aldehydes with 2-allylisourea took place in the presence of a catalytic amount of a palladium(0) complex under neutral and mild conditions.Scope and limitations of this novel method have been investigated.
Inoue, Yoshio,Toyofuku, Masanori,Taguchi, Masaaki,Okada, Shin-ichi,Hashimoto, Harukichi
p. 885 - 892
(2007/10/02)

A PRACTICAL SYNTHESIS OF MYRCENOL BY PALLADIUM COMPLEX-CATALYZED ELIMINATION REACTION
A Palladium complex-catalyzed elimination reaction of allyl amines was studied to establish a practical process for production of myrcenol.The catalytic elimination occurred smoothly with the cationic Pd(II) complexes.Among a variety phosphorous ligands, the tetramethylene and the pentamethylene diphosphine ligands proved to be the best ligand with respects to the catalytic activity and selectivity.
Kumobayashi, Hidenori,Mitsuhashi, Shigeru,Akutagawa, Susumu,Ohtsuka, Sei
p. 157 - 160
(2007/10/02)

Rearrangement of Linalool, Geraniol, and Nerol and Their Derivatives
Acid-catalyzed conversion of linalool into geraniol, nerol, and α-terpineol is slower than the corresponding reactions of geraniol and nerol, because the tertriary linalyl carbocation reverts to linalool rather than going forward to rearranged products.The linalyl carbocation does not lose its stereochemical identity, and oxygen exchange of linalool is faster than rearrangement or cyclization.Solvolyses of linalyl esters and chloride are faster than those of the geranyl and neryl derivatives.These solvolyses are different from acid heterolysis of linalool in that there is extensive racemization of linalool, but cyclization to α-terpineol goes with considerable retention of configuration.Participation by the 6,7-double bond controls the stereochemistry of linalool heterolysis and solvolysis of linalyl esters, but it does not markedly affect the reaction rates.
Cori, Osvaldo,Chayet, Liliana,Perez, Luz Maria,Bunton, Clifford A.,Hachey, David
p. 1310 - 1316
(2007/10/02)

SYNTHESE STEREOSELECTIVE DE DIENES CONJUGUES A PARTIR D'ALCOOLS α-ALLENIQUES
The reaction of a Grignard reagent with an α-allenic phosphate leads exclusively in every studied case to 1,3-dienes.A high stereoselectivity is observed for the formation of both double bonds; particularly, the organometallic species attacks preferentially in a trans direction from a group located on the terminal allenic carbon.In the case of the esters of secondary alcohols, it is more difficult to determine the factors which govern the stereochemistry of the other double bond.The Z configuration is then favoured in the reaction phosphate + RMgX but the E configuration is predominant in the reaction acetate + R2CuLi.
Djahanbini, Dariouche,Cazes, Bernard,Gore, Jacques
p. 3645 - 3656
(2007/10/02)

SYNTHESIS OF 2-SUBSTITUTED 1,3-BUTADIENYL COMPOUNDS BY PALLADIUM-CATALYZED REGIOSELECTIVE 1,2-ELIMINATION REACTION OF METHYLVINYLCARBINOL ACETATES
Alkylation of the dianion of 3-methyl-3-buten-2-ol, followed by acetylation and palladium-catalyzed 1,2-elimination reaction of the so obtained methylvinylcarbinol acetates allows to synthesize regioselectively 2-substituted 1,3-butadienyl compounds having high isomeric purity.
Carpita, Adriano,Bonaccorsi, Fabrizio,Rossi, Renzo
p. 5193 - 5196
(2007/10/02)

α-HALOALKANESULFONYL BROMIDES IN ORGANIC SYNTHESIS. 4. REGIOSELECTIVE γ-DEPROTONATION OF α,β-UNSATURATED SULFONES. A SIMPLE SYNTHESIS OF 2-ALKYL-1,3-BUITADIENES
A simple method for converting 2-methyl-1-alkenes into 2-alkyl-1,3-butadienes is described.Evidence for complexation of lithium cations by sulfonyl groups in the course of reactions of α,β-unsaturated sulfones with LiOt-Bu is presented.
Block, Eric,Eswarakrishnan, Venkatachalam,Gebreyes, Kassu
p. 5469 - 5472
(2007/10/02)

COPPER INDUCED SOLVOLYSIS OF SULFUR COMPOUNDS
The displacement of a phenylthio group by an acetate ion some allylic or α-alcoxy sulfides and thioacetals was cleanly performed by treating them with a mixture of copper powder and cupric acetate in acetic acid.
Uguen, D.
p. 541 - 542
(2007/10/02)

A New Synthesis of Olefins via the Elimination Reaction of β-Tributylstannyl Organosulfur Compounds
Organosulfur compounds on treatment with butyllithium in tetrahydrofuran followed by tributylstannylmethyl iodide 1 afforded olefins.The reaction was found to proceed via the destannylsulfurization of the initially formed β-stannyl organosulfur compounds.Thus, allyl 2-pyridyl sulfides 2 or allyl phenyl sulfones 12 were converted into 1,3-dienes 4.Compounds 13 and 15 were converted into the olefins 14 and 17.Furthermore, the reaction was applied to the synthesis of α-substituted vinyl sulfides 24 and allene 27.The stereochemistry of the double bond is discussed.Keywords - destannylsulfurization; allyl 2-pyridyl sulfide; allyl phenyl sulfone; synthesis of olefin; 1,3-diene; vinyl sulfide; β-tributylstannyl organosulfur compound.
Ochiai, Masahito,Ukita, Tatsuzo,Fujita, Eiichi,Tada, Shin-ichi
p. 1829 - 1839
(2007/10/02)

PHOTOCHEMICAL TRANSFORMATIONS-III; ORGANIC IODIDES (Part 3): GERANYL AND NERYL IODIDES AND 2(E),6(E)- AND 2(Z),6(E)-FARNESYL IODIDES
Solution photolysis of geranyl and neryl iodides, and 2(E),6(E)- and 2(Z),6(E)-farnesyl iodides has been carried out.Products arising from simple elimination as well as ?-participation are formed.Thus, both geranyl and neryl iodides furnished, besides some unidentified compounds, myrcene, cis-ocimene, limonene and terpinolene, though in different proportions.Likewise, the sesquiterpene analogues yielded different amounts of trans-β-farnesene, β-bisabolene, trans-α-bisabolene and ar-curcumene.Results have been discussed in terms of ionic intermediates.
Saplay, K. M.,Damodaran, N. P.,Dev, Sukh
p. 2999 - 3004
(2007/10/02)

MOLYBDENUM CATALYZED ELIMINATIONS OF ALLYLIC ACETATES. NEW DIENE SYNTHESIS
Allyl acetates smoothly eliminate the elements of acetic acid in the presence of O,N-bis(trimethylsilyl)acetamide and molybdenum hexacarbonyl; a simple sequence permits elaboration of saturated aldehydes into α,β,γ,δ-dienoates which resulted in a four step synthesis of trichonine.
Trost, Barry M.,Lautens, Mark,Peterson, Brian
p. 4525 - 4528
(2007/10/02)

CROSS-COUPLING REACTION OF ALLYL BROMIDES WITH ORGANOTIN REAGENTS CATALYZED BY ZINC CHLORIDE
Myrcene and β-farnesene have been synthesized by the zinc chloride catalyzed coupling reaction of (2-methylene-3-butenyl)trimethyltin with prenyl bromide and geranyl bromide, respectively; vitamin K1 was synthesized by a similar coupling reaction.
Godschalx, J. P.,Stille, J. K.
p. 1905 - 1908
(2007/10/02)