- Method for synthesizing bark beetle pheromone
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The bark beetle pheromone is (1S, 4R) -4 - isopropyl -1 - methyl -2 -cyclohexene -1 - alcohol, and the synthetic method comprises the following steps: forming a clathrate compound with (S)- (-) - limonene and carrying out catalytic hydrogenation reaction
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Paragraph 0026-0027; 0031-0032
(2021/09/01)
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- Cobalt-Catalyzed Desymmetric Isomerization of Exocyclic Olefins
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Chiral cyclic olefins, 1-methylcyclohexenes, are versatile building blocks for the synthesis of pharmaceuticals and natural products. Despite the prevalence of these structural motifs, the development of efficient synthetic methods remains an unmet challenge. Herein we report a novel desymmetric isomerization of exocyclic olefins using a series of newly designed chiral cobalt catalysts, which enables a straightforward construction of chiral 1-methylcyclohexenes with diversified functionalities. The synthetic utility of this methodology is highlighted by a concise and enantioselective synthesis of a natural product, β-bisabolene. The versatility of the reaction products is further demonstrated by multifarious derivatizations.
- Lan, Yu,Liu, Qiang,Liu, Shihan,Liu, Xufang,Rong, Xianle
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supporting information
p. 20633 - 20639
(2021/12/17)
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- Scalable Total Synthesis of (-)-Vinigrol
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Vinigrol is a structurally and stereochemically complex natural product that displays various potent pharmacological activities, including the capability to modulate TNF-α. A new and efficient synthetic route toward this natural product has been developed to complete the asymmetric synthesis of (-)-vinigrol and provide over 600 mg of material, manifesting the power of macrocyclic stereocontrol and transannular Diels-Alder reaction.
- Yu, Xuerong,Xiao, Lianghong,Wang, Zechun,Luo, Tuoping
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supporting information
p. 3440 - 3443
(2019/03/07)
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- Identification of an Asexual Reproduction Inducer of Phytopathogenic and Toxigenic Fusarium
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Asexual and sexual reproduction are the most important biological events in the life cycle of phytopathogenic and toxigenic Fusarium and are responsible for disease epidemics. However, the signaling molecules which induce the asexual reproduction of Fusarium are unknown. Herein we describe the structure elucidation, including the absolute configuration, of Fusarium asexual reproduction inducer (FARI), a new sesquiterpene derivative, by spectroscopic analysis, total synthesis, and conidium-inducing assays of synthetic isomers. We have also uncovered the universality of FARI among Fusarium species. Moreover, a mechanism-of-action study suggested that the Gpmk1 and LaeA signaling pathways are required for conidium formation induced by FARI; conversely, the Mgv1 of mitogen-activated protein kinase is not involved in conidium formation. FARI exhibited conidium-inducing activity at an extremely low dose and high stereoselectivity, which may suggest the presence of a stereospecific target.
- Qi, Jianhua,Cheng, Lihong,Sun, Yujuan,Hirata, Yushi,Ushida, Naoki,Ma, Zhonghua,Osada, Hiroyuki,Nishikawa, Toshio,Xiang, Lan
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supporting information
p. 8100 - 8104
(2018/06/04)
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- Selective carvone hydrogenation to dihydrocarvone over titania supported gold catalyst
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Selective hydrogenation of natural carvone to industrially valuable dihydrocarvone was carried out at 100°C under hydrogen pressure over a 1.9wt.% Au/TiO2 catalyst. The gold catalyst has demonstrated high activity as well as stereo- and chemoselectivity in conjugated C=C double bond hydrogenation with predominant formation of trans-dihydrocarvone. The catalytic activity and trans-to cis-isomers ratio were shown to strongly depend on the solvent. In a range of C1 - C3 alcohol solvents both catalytic activity and trans-to cis-dihydrocarvone ratio increased following the order: 2-propanol a nearly complete carvone conversion (90%) after 13h in the case of methanol, with the trans-to cis-dihydrocarvone ratio being about 1.8. Based on the transition state theory a quantitative description of trans-to cis-dihydrocarvone ratio variations in different solvents was made.
- Demidova,Suslov,Simakova,Simakova,Volcho,Salakhutdinov,Murzin
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p. 189 - 194
(2015/03/14)
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- Microwave assisted bi-functional activation of β-bromo-tert-alcohols
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Microwave-assisted dehydration-oxidation of β-bromo-tert-alcohols to afford 2,3-unsaturated ketones in good yield is reported. The reaction of substrates with DMSO in 1:1 ratio (w/v) is promoted by ZnS in a solvent-free condition. A concurrent bi-functional activation of trans-vicinal bromo- and hydroxyl groups with ZnS is elucidated. This is a new observation under microwave and applies to β-bromo-tert-alcohols derived from 1,4-disubstitued-1-cyclohexenes. It is very useful in the synthesis of 2,3-unsaturated ketones derived from monoterpenes which are valuable flavour compounds. [Figure not available: see fulltext.]
- Kannan, Nandini,Rangaswamy, Manjunatha Javagal,Kemapaiah, Bettadaiah Bheemanakere
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p. 1405 - 1410
(2015/11/09)
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- Eco-friendly kinetic separation of trans-limonene and carvomenthene oxides
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Kinetic separation of trans-limonene oxide and trans-carvomenthene oxide was achieved in high yield by selective ring opening of their cis-epoxides in the presence of InCl3 catalyst in water. Catalytic activity of InCl3 was conserved
- Santosh Kumar, S Chandrappa,Manjunatha, Javagal Rangaswamy,Srinivas, Pullabhatla,Bettadaiah, Bheemanakere Kemapaiah
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p. 875 - 880
(2014/07/07)
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- Selective reduction of dienes/polyenes using sodium borohydride/catalytic ruthenium(III) in various liquid amide aqueous mixtures
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An efficient method to effect selective reduction of several structurally diverse dienes and an unsymmetrical triene is reported. The reduction is facile at 0 °C in a liquid amide aqueous solution containing sodium borohydride in the presence of 15 mol % ruthenium(III) chloride. The chemoselectivity of the reaction is controlled by proper choice of the liquid amide solvent.
- Babler, James H.,Ziemke, David W.,Hamer, Robert M.
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p. 1754 - 1757
(2013/04/10)
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- FRAGRANCES WITH NOTE OF LILY OF THE VALLEY
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A compound of formula (I) is described and use thereof as fragrance, especially as lily-of-the-valley fragrance and/or as an agent for increasing the substantivity and/or the retention of a fragrance preparation and/or as a fixative.
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Paragraph 0267; 0268; 0269
(2013/04/13)
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- Reduction of carbon-carbon double bonds using organocatalytically generated diimide
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(Chemical Equation Presented) An efficient method has been developed for the reduction of carbon-carbon double bonds with diimide, catalytically generated in situ from hydrazine hydrate. The employed catalyst is prepared in one step from riboflavin (vitamin B2). Reactions are carried out in air and are a valuable alternative when metal-catalyzed hydrogenations are problematic.
- Smit, Christian,Fraaije, Marco W.,Minnaard, Adriaan J.
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supporting information; experimental part
p. 9482 - 9485
(2009/04/06)
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- Determination of the absolute configuration of quercivorol, (1S,4R)-p-menth-2-en-1-ol, an aggregation pheromone of the ambrosia beetle Platypus quercivorus (Coleoptera: Platypodidae)
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A pair of enantiomers of trans-p-menth-2-en-1-ol, an aggregation pheromone of Platypus quercivorus, was synthesized from (S)- and (R)-limonene. The retention time of the aggregation pheromone from the insect coincided with that of (1S,4R)-p-menth-2-en-1-ol synthesized from (S)-limonene from GC analyses with a chiral column, enabling the absolute configuration of the aggregation pheromone to be determined as (1S,4R).
- Kashiwagi, Takehiro,Nakashima, Tadakazu,Tebayashi, Shin-Ich,Kim, Chul-Sa
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p. 2544 - 2546
(2008/02/08)
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- Synthesis of (1S,4R)-4-isopropyl-1-methyl-2-cyclohexen-1-ol, the aggregation pheromone of the ambrosia beetle Platypus quercivorus, its racemate, (1R,4R)- and (1S,4S)-isomers
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(S)-Perillyl alcohol was converted to (R)-cryptone (91.5-93% ee) in six steps, which was then treated with methyllithium to give (1S,4R)-4-isopropyl-1-methyl-2-cyclohexen-1-ol, the aggregation pheromone of the ambrosia beetle Platypus quercivorus. The racemic pheromone was also prepared by methylation of (±)-cryptone. Both (1R,4R)- and (1S,4S)-isomers (98% ee) of the pheromone were synthesized from the enantiomers of dihydrolimonene oxide.
- Mori, Kenji
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p. 2133 - 2142
(2007/10/03)
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- Preparation and molecular and electronic structures of iron(0) dinitrogen and silane complexes and their application to catalytic hydrogenation and hydrosilation
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Reduction of the five-coordinate iron(II) dihalide complexes ( iPrPDI)FeX2 (iPrPDI = ((2,6-CHMe 2)2C6H3N=CMe)2C 5H3N; X = Cl, Br) with sodium amalgam under 1 atm of dinitrogen afforded the square pyramidal, high spin iron(0) bis(dinitrogen) complex (iPrPDI)Fe(N2)2. In solution, ( iPrPDI)Fe(N2)2 loses 1 equiv of N2 to afford the mono(dinitrogen) adduct (iPrPDI)Fe(N2) 2. Both dinitrogen compounds serve as effective precatalysts for the hydrogenation and hydrosilation of olefins and alkynes. Effecient catalytic reactions are observed with low catalyst loadings (≤0.3 mol %) at ambient temperature in nonpolar media. The catalytic hydrosilations are selective in forming the anti-Markovnikov product. Structural characterization of a high spin iron(0) alkyne and a bis(silane) σ-complex has also been accomplished and in combination with isotopic labeling studies provides insight into the mechanism of both catalytic C-H and catalytic C-Si bond formation.
- Bart, Suzanne C.,Lobkovsky, Emil,Chirik, Paul J.
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p. 13794 - 13807
(2007/10/03)
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- Stereoselective synthesis of (6R)- and (6S)-diosphenol and Ψ-diosphenol
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Methods are discussed for the stereoselective synthesis of the (R)-and (S)-enantiomers of the diosphenols (5)-(8) by utilizing the commercially available stereoisomers (9), (12), (23) and (25) of carvone and limonene, respectively, as chiral starting materials.
- Schneider, David F,Viljoen, Murray S
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p. 5307 - 5315
(2007/10/03)
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- Asymmetric synthesis of the tricyclic core of NGF-inducing cyathane diterpenes via a transition-metal-catalyzed [5 + 2] cycloaddition.
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[reaction: see text] A concise asymmetric synthesis of the tricyclic core of cyathane diterpenes is described, based on a novel transition-metal-catalyzed intramolecular [5 + 2] cycloaddition of ynone-vinylcyclopropane 10 (assembled from commercially avai
- Wender,Bi,Brodney,Gosselin
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p. 2105 - 2108
(2007/10/03)
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- Periplanone Total Synthesis via Intramolecular Pinacol Coupling
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We have carried out an enantioselective synthesis of (-)-periplanone C by a route involving titanium-induced, intramolecular pinacol coupling reaction of 1,10 keto aldehyde as the key step.The coupling occurs with predictable stereochemistry to give a mix
- McMurry, John E.,Siemers, Nathan O.
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p. 4505 - 4508
(2007/10/02)
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- A convergent synthesis of triquinane sesterterpenes. Enantioselective synthesis of (-)-retigeranic acid A
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The total synthesis of enantiomerically pure (-)-retigeranic acid A has been achieved in a convergent manner from (R)-(+)-pulegone and (S)-(-)-limonene. In the pivotal coupling step, the Grignard reagent derived from optically pure bromide 46 was found to
- Wright,Drtina,Roberts,Paquette
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p. 5806 - 5817
(2007/12/18)
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- Synthesis and Chiroptical Properties of Some Piperidin-2-ones
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The synthesis of optically pure (R)-(+)-4-isopropylpiperidin-2-one, (R)-(+)-4-isopropyl-4-methylpiperidin-2-one, and (R)-(+)-5-methylpiperidin-2-one in high yields from monocyclic terpene precursors are described.The CD spectra of these compounds are reported, and the chiroptical properties of δ-lactams are examined in terms of current theories for the amide chromophore.It is concluded that slight, conformationally induced nonplanarity of the amide chromophore is responsible for signs of the longest wavelenght bands in the CD spectra of these and related compounds.
- Jackman, L. M.,Webb, R. Lee,Yick, H. C.
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p. 1824 - 1831
(2007/10/02)
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- Reaction of (+)carvomenthol tosylate with KCN in aprotic solvents; (1S,2R,4S) 1-methyl-4-isopropylcyclohexane-2-carbonitrile
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Reaction of (+)carvomenthol tosylate with KCN in pyridine solution was proved to produce a mixture of hydrocarbons; in DMF additionally a small quantity of alcohols was obtained.However, in DMSO sterically homogeneous (-)(1S,2R,4S) 1-methyl-4-isopropylcyclohexane-2-carbonitrile ((-)neocarvomenthyl carbonitrile) was the main product.The structure of the compound obtained was determined on the basis of spectral data, elemental analysis, and chemical transformations which indicated configurational relation of the title compound to the known (-)(1S,2R,4S) neocarvomenthyl amine.
- Rykowski, Zbigniew
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p. 2271 - 2278
(2007/10/02)
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