- Stereocontrolled Total Synthesis of (-)-Isocelorbicol and Its Elaboration to Natural Dihydro-β-agarofuran Esters
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The first total synthesis of four naturally occurring dihydro-β-agarofuran esters has been accomplished via a highly stereocontrolled 14-step access to their common core triol, (-)-isocelorbicol. A semipinacol rearrangement of an epoxy alcohol to install a quaternary carbon, diastereoselective conjugate reduction of a spirocyclic butenolide for the establishment of a methyl-bearing chiral center, and ring-closing metathesis to construct the decalin ring system were exploited as the key steps for the high-yielding synthesis of (-)-isocelorbicol.
- Mohri, Tomoyo,Takahashi, Yusuke,Kwon, Eunsang,Kuwahara, Shigefumi,Ogura, Yusuke
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- Lewis-Acid-Mediated Union of Epoxy-Carvone Diastereomers with Anisole Derivatives: Mechanistic Insight and Application to the Synthesis of Non-natural CBD Analogues
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The use of trimethylsilyl trifluoromethanesulfonate as a mild means to unite epoxy-carvone silyl ethers with anisole derivatives to yield products that are structurally similar to the CBD scaffold is reported. Importantly, unlike related methods, this process can utilize both epoxy-carvone diastereomers and does not require the use of air/moisture-sensitive organometallic reagents. Several examples of aryl nucleophiles as well as mechanistic insight based on in silico computational analysis are presented.
- Bailey, Sophia J.,Sapkota, Rishi R.,Golliher, Alexandra E.,Dungan, Barry,Talipov, Marat,Holguin, F. Omar,Maio, William A.
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- Enantiospecific Entry to a Common Decalin Intermediate for the Syntheses of Highly Oxygenated Terpenoids
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Herein, we describe an enantiospecific route to one enantiomer of a common decalin core that is present in numerous highly oxygenated terpenoids. This intermediate is accessed in eight steps from (R)-carvone, an inexpensive, enantioenriched building block, which can be elaborated to the desired bicycle through sequential Fe(III)-catalyzed reductive olefin coupling and Dieckmann condensation. The same synthetic route may be applied to (S)-carvone to afford the enantiomer of this common intermediate for other applications.
- Nagasawa, Shota,Jones, Kerry E.,Sarpong, Richmond
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- Catalytic Performance of Zr-Based Metal–Organic Frameworks Zr-abtc and MIP-200 in Selective Oxidations with H2O2
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The catalytic performance of Zr-abtc and MIP-200 metal–organic frameworks consisting of 8-connected Zr6 clusters and tetratopic linkers was investigated in H2O2-based selective oxidations and compared with that of 12-coordinated UiO-66 and UiO-67. Zr-abtc demonstrated advantages in both substrate conversion and product selectivity for epoxidation of electron-deficient C=C bonds in α,β-unsaturated ketones. The significant predominance of 1,2-epoxide in carvone epoxidation, coupled with high sulfone selectivity in thioether oxidation, points to a nucleophilic oxidation mechanism over Zr-abtc. The superior catalytic performance in the epoxidation of unsaturated ketones correlates with a larger amount of weak basic sites in Zr-abtc. Electrophilic activation of H2O2 can also be realized, as evidenced by the high activity of Zr-abtc in epoxidation of the electron-rich C=C bond in caryophyllene. XRD and FTIR studies confirmed the retention of the Zr-abtc structure after the catalysis. The low activity of MIP-200 in H2O2-based oxidations is most likely related to its specific hydrophilicity, which disfavors adsorption of organic substrates and H2O2.
- Maksimchuk, Nataliya V.,Ivanchikova, Irina D.,Cho, Kyung Ho,Zalomaeva, Olga V.,Evtushok, Vasiliy Yu.,Larionov, Kirill P.,Glazneva, Tatiana S.,Chang, Jong-San,Kholdeeva, Oxana A.
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p. 6985 - 6992
(2021/03/17)
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- Activation of H2O2over Zr(IV). Insights from Model Studies on Zr-Monosubstituted Lindqvist Tungstates
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Zr-monosubstituted Lindqvist-type polyoxometalates (Zr-POMs), (Bu4N)2[W5O18Zr(H2O)3] (1) and (Bu4N)6[{W5O18Zr(μ-OH)}2] (2), have been employed as molecular models to unravel the mechanism of hydrogen peroxide activation over Zr(IV) sites. Compounds 1 and 2 are hydrolytically stable and catalyze the epoxidation of C?C bonds in unfunctionalized alkenes and α,β-unsaturated ketones, as well as sulfoxidation of thioethers. Monomer 1 is more active than dimer 2. Acid additives greatly accelerate the oxygenation reactions and increase oxidant utilization efficiency up to >99%. Product distributions are indicative of a heterolytic oxygen transfer mechanism that involves electrophilic oxidizing species formed upon the interaction of Zr-POM and H2O2. The interaction of 1 and 2 with H2O2 and the resulting peroxo derivatives have been investigated by UV-vis, FTIR, Raman spectroscopy, HR-ESI-MS, and combined HPLC-ICP-atomic emission spectroscopy techniques. The interaction between an 17O-enriched dimer, (Bu4N)6[{W5O18Zr(μ-OCH3)}2] (2′), and H2O2 was also analyzed by 17O NMR spectroscopy. Combining these experimental studies with DFT calculations suggested the existence of dimeric peroxo species [(μ-?2:?2-O2){ZrW5O18}2]6- as well as monomeric Zr-hydroperoxo [W5O18Zr(?2-OOH)]3- and Zr-peroxo [HW5O18Zr(?2-O2)]3- species. Reactivity studies revealed that the dimeric peroxo is inert toward alkenes but is able to transfer oxygen atoms to thioethers, while the monomeric peroxo intermediate is capable of epoxidizing C?C bonds. DFT analysis of the reaction mechanism identifies the monomeric Zr-hydroperoxo intermediate as the real epoxidizing species and the corresponding α-oxygen transfer to the substrate as the rate-determining step. The calculations also showed that protonation of Zr-POM significantly reduces the free-energy barrier of the key oxygen-transfer step because of the greater electrophilicity of the catalyst and that dimeric species hampers the approach of alkene substrates due to steric repulsions reducing its reactivity. The improved performance of the Zr(IV) catalyst relative to Ti(IV) and Nb(V) catalysts is respectively due to a flexible coordination environment and a low tendency to form energy deep-well and low-reactive Zr-peroxo intermediates.
- Abramov, Pavel A.,Carbó, Jorge J.,Chesalov, Yuriy A.,Eltsov, Ilia V.,Errington, R. John,Evtushok, Vasilii Yu.,Glazneva, Tatyana S.,Ivanchikova, Irina D.,Kholdeeva, Oxana A.,Maksimchuk, Nataliya V.,Maksimov, Gennadii M.,Poblet, Josep M.,Solé-Daura, Albert,Yanshole, Vadim V.,Zalomaeva, Olga V.
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p. 10589 - 10603
(2021/09/02)
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- Epoxy-amine oligomers from terpenes with applications in synergistic antifungal treatments
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A bis-epoxide monomer was synthesised in two steps from (R)-carvone, a terpenoid renewable feedstock derived from spearmint oil, and used to prepare β-aminoalcohol oligomers in polyaddition reactions with bis-amines without requiring solvent or catalyst. A sub-set of the resultant materials were readily water soluble and were investigated for antifungal activity in combination with the fungicide iodopropynyl-butylcarbamate (IPBC) or the antifungal drug amphotericin B. The oligo-(β-aminoalcohol)s alone were inactive against Trichoderma virens and Candida albicans but in combination with IPBC and amphotericin B demonstrated synergistic growth-inhibition of both fungi. Quantitative analysis showed that the presence of the terpene-based oligomers decreased the minimum inhibitory concentration (MIC) of IPBC by up to 64-fold and of amphotericin B by 8-fold. The efficacy of the combined formulation was further demonstrated with agar disk diffusion assays, which revealed that IPBC and amphotericin B reduced the growth of the fungi, as shown by zones of inhibition, to a greater extent when in the presence of the oligo-(β-aminoalcohol)s. These data suggest potential future use of these renewable feedstock derived oligomers in antifungal material and related biomedical applications.
- O'Brien, Dara M.,Vallieres, Cindy,Alexander, Cameron,Howdle, Steven M.,Stockman, Robert A.,Avery, Simon V.
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supporting information
p. 5222 - 5229
(2019/09/13)
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- A versatile, RCM based approach to eudesmane and dihydroagarofuran sesquiterpenoids from (-)-carvone: A formal synthesis of (-)-isocelorbicol
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An enantiospecific and diversity oriented approach to a range of functionalized eudesmane, nor-, iso-, and dihydroagarofuran frameworks from (-)-carvone is delineated. The cornerstone of this approach is the installation of the quaternary carbon center through reductive opening of the carvone epoxide and setting-up of RCM reaction to generate the bicyclic eudesmane framework. Various options like carbocation mediated oxycyclization and intramolecular hydroxy directed epoxide opening have been explored for the construction of the bridged tetrahydrofuran moiety. Among the several eudesmane and dihydroagarofurans accessed during the present study, one has been previously elaborated to isocelorbicol, thus constituting its formal synthesis.
- Senthil Kumaran,Mehta, Goverdhan
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p. 1718 - 1731
(2015/03/30)
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- Comparative anticonvulsant study of epoxycarvone stereoisomers
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Stereoisomers of the monoterpene epoxycarvone (EC), namely (+)-cis-EC, (-)-cis-EC, (+)-Trans-EC, and (-)-Trans-EC, were comparatively evaluated for anticonvulsant activity in specific methodologies. In the pentylenetetrazole (PTZ)-induced anticonvulsant test, all of the stereoisomers (at 300 mg/kg) increased the latency to seizure onset, and afforded 100% protection against the death of the animals. In the maximal electroshock-induced seizures (MES) test, prevention of tonic seizures was also verified for all of the isomers tested. However, the isomeric forms (+) and (-)-Trans-EC showed 25% and 12.5% inhibition of convulsions, respectively. In the pilocarpine-induced seizures test, all stereoisomers demonstrated an anticonvulsant profile, yet the stereoisomers (+) and (-)-Trans-EC (at 300 mg/kg) showed a more pronounced effect. A strychnine-induced anticonvulsant test was performed, and none of the stereoisomers significantly increased the latency to onset of convulsions; the stereoisomers probably do not act in this pathway. However, the stereoisomers (+)-cis-EC and (+)-Trans-EC greatly increased the latency to death of the animals, thus presenting some protection. The four EC stereoisomers show promise for anticonvulsant activity, an effect emphasized in the isomers (+)-cis-EC, (+)-Trans-EC, and (-)-Trans-EC for certain parameters of the tested methodologies. These results serve as support for further research and development of antiepileptic drugs from monoterpenes.
- Salgado, Paula Regina Rodrigues,Da Fonsêca, Diogo Vilar,Braga, Renan Marinho,De Melo, Cynthia Germoglio Farias,Andrade, Luciana Nalone,De Almeida, Reinaldo Nóbrega,De Sousa, Dami?o Pergentino
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p. 19660 - 19673
(2015/12/23)
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- Total synthesis of schilancitrilactones B and C
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The first total syntheses of schilancitrilactones B and C have been accomplished in 17 steps (longest linear sequence) from commercially available materials. Key steps include an intramolecular radical cyclization to provide the seven-membered ring, late-stage iodination, and an intermolecular radical addition reaction to complete the total synthesis. In step: The first total syntheses of schilancitrilactones B and C have been accomplished by using an intramolecular radical cyclization to provide the seven-membered ring, late-stage iodination, and an intermolecular radical addition reaction as key steps. The approach provides a sequence for the syntheses of compounds related to the schilancitrilactones, as well as their derivatives and analogues.
- Wang, Liang,Wang, Hengtao,Li, Yihang,Tang, Pingping
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supporting information
p. 5732 - 5735
(2015/09/21)
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- Design and synthesis of simple, yet potent and selective non-ring-A pyripyropene A-based inhibitors of acyl-coenzyme A: Cholesterol acyltransferase 2 (ACAT2)
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A series of pyripyropene A-based compounds were designed and synthesized by opening the upper section of the A-ring, which significantly simplifies the structure and synthesis from commercially available starting materials. Representative compound (-)-3 exhibited potent activity against ACAT2 and greater selectivity for ACAT2 than for ACAT1.
- Zhan, Yang,Zhang, Xiao-Wei,Xiong, Ying,Li, Bo-Liang,Nan, Fa-Jun
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supporting information
p. 747 - 751
(2016/01/12)
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- Titanocene-promoted stereoselective eliminations on epoxy alcohols derived from R-(-)-carvone
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The reaction of several stereoisomeric epoxy alcohols, obtained from R-(-)-carvone, and their corresponding formates, acetates, and benzoates, promoted by Cp2TiCl has been studied. The different outcomes of the reaction of epoxy derivatives are rationalized in terms of mechanistically biased processes. The radicals emerging from oxirane cleavage provide two types of reaction: dehydroxylation (deoxycarbonylation) and dehydrogenation. The results offer considerable support for the radical elimination theory of hydroxyl, formyloxyl, and acetoxyl groups. The inability of tertiary radicals to be reduced by the Ti(III) complex is demonstrated unequivocally.
- Fernández-Mateos,Herrero Teijón,Rubio González
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p. 1611 - 1616
(2013/02/25)
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- Application of the Rodriguez-Pattenden photo-ring contraction: Total synthesis and configurational reassignment of 11-gorgiacerol and 11-epigorgiacerol
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A stereospecific photochemical ring contraction was used as the key step in the first total synthesis of the marine pseudopteranyl diterpene 11-gorgiacerol and its 11-epimer. The synthesis allowed the correction of the configurations that had been misassigned in the literature. In addition, some novel pseudopteranyl derivatives have been made.
- Weinstabl, Harald,Gaich, Tanja,Mulzer, Johann
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supporting information; experimental part
p. 2834 - 2837
(2012/07/28)
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- Unique salt effect on highly selective synthesis of acid-labile terpene and styrene oxides with a tungsten/Hcatalytic system under acidic aqueous conditions
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Acid-labile epoxides such as terpene and styrene oxides are effectively synthesized in high yields with good selectivities using tungsten-catalyzed hydrogen peroxide epoxidation in the presence of NaO The salt effect is thought to originate with the addition of a saturated amount of NaOto aqueous H this addition strongly inhibited the undesired hydrolysis of the acid-labile epoxy products, despite the biphasic conditions of substrate as oil phase and Has acidic aqueous phase.
- Hachiya, Houjin,Kon, Yoshihiro,Ono, Yutaka,Takumi, Kiyoshi,Sasagawa, Naoki,Ezaki, Yoichiro,Sato, Kazuhiko
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experimental part
p. 1672 - 1678
(2012/07/16)
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- Total synthesis and absolute configuration of malyngamide W
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A concise enantioselective synthesis of malyngamide W (1) and its 2′-epimer was described. The strategy was based on three key steps: (1) ozonolysis of compound 11 which was derived from (R)-(-)-carvone 8, followed by copper-iron-catalyzed rearrangement to give the key cyclohex-2-enone intermediate 5, (2) Nozaki-Hiyama-Kishi coupling reaction between aldehyde 4 and iodide 14 to afford alcohol 3, and (3) asymmetric (R)-CBS reduction of the ketone functionality in compound 21 to establish the C-2′ chiral center in the target compound 1. The absolute configuration of malyngamide W (1) was thus confirmed via the synthesis of 1 and 2′-epi-1.
- Qi, Xian-Liang,Zhang, Jun-Tao,Feng, Jian-Peng,Cao, Xiao-Ping
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supporting information; experimental part
p. 3817 - 3824
(2011/06/21)
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- Synthesis of bicyclo[4.2.0]octan-2-ol, a substructure of solanoeclepin A
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A sesterterpenoid solanoeclepin A (1) has a unique structure including a bicyclo[4.2.0]octane substructure, for which a new synthetic methodology is explored particularly to cyclize functionalized cyclobutane rings. An optically active (R)-carvone and a racemic cyclohexenone were each converted into the respective epoxyvinylsulfones, and then subjected to the heteroatom-directed conjugate addition (HADCA) by a lithium acetylide nucleophile. The intermediate carbanions from HADCA were used for the following epoxide opening reaction yielding the four-membered carbocyclic products.
- Isobe, Minoru,Niyomchon, Supaporn,Cheng, Chia-Yi,Hasakunpaisarn, Anuch
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supporting information; experimental part
p. 1847 - 1850
(2011/04/25)
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- An effective synthesis of acid-sensitive epoxides via oxidation of terpenes and styrenes using hydrogen peroxide under organic solvent-free conditions
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An efficient epoxidation process for various terpenes and styrenes using a hydrogen peroxide-tungsten catalytic system with organic solvent-and halide-free conditions was developed. In the presence of the catalytic system, Na 2WO4, PhP(O)(OH)2, and [Me(n-C 8H17)3N]HSO4, and under weak acidic conditions, hydrogen peroxide successfully epoxidized -pinene to -pinene oxide in 95% selectivity at 91% conversion, while the previously published conditions utilizing NH2CH2P(O)(OH)2 as a promoter provided no epoxide. Georg Thieme Verlag Stuttgart.
- Kon, Yoshihiro,Hachiya, Houjin,Ono, Yutaka,Matsumoto, Tomohiro,Sato, Kazuhiko
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experimental part
p. 1092 - 1098
(2011/05/14)
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- Unique salt effect on the high yield synthesis of acid-labile terpene oxides using hydrogen peroxide under acidic aqueous conditions
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Acid-labile epoxides such as -pinene oxide are (effectively) synthesized in high yield from the epoxidation of terpenes with aqueous H2O 2 catalyzed by Na2WO4, [Me(n-C 8H17)3N]HSO4, and PhP(O)(OH) 2 in the presence of Na2SO4 as an auxiliary additive under organic solvent-free conditions at ambient temperature. Origin of the salt effect is considered that the addition of a saturated amount of Na2SO4 to aqueous H2O2 strongly inhibited the undesired hydrolysis of the acid-labile epoxide products, despite the highly acidic reaction conditions. Georg Thieme Verlag Stuttgart · New York.
- Hachiya, Houjin,Kon, Yoshihiro,Ono, Yutaka,Takumi, Kiyoshi,Sasagawa, Naoki,Ezaki, Yoichiro,Sato, Kazuhiko
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scheme or table
p. 2819 - 2822
(2012/01/02)
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- Structure-function relationships and crystal structures of the vitamin D receptor bound 2α-methyl-(20S,23S)- and 2α-methyl-(20S,23R)- epoxymethano-1α,25-dihydroxyvitamin D3
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The vitamin D nuclear receptor is a ligand-dependent transcription factor that controls multiple biological responses such as cell proliferation, immune responses, and bone mineralization. Numerous 1α,25(OH)2D 3 analogues, which exhibit low calcemic side effects and/or antitumoral properties, have been synthesized. We recently showed that the synthetic analogue (20S,23S)-epoxymethano-1α,25-dihydroxyvitamin D 3 (2a) acts as a 1α,25(OH)2D3 superagonist and exhibits both antiproliferative and prodifferentiating properties in vitro. Using this information and on the basis of the crystal structures of humanVDRligand binding domain (hVDRLBD) bound to 1α,25(OH)2D3, 2α-methyl-1α,25(OH) 2D3, or 2a, we designed a novel analogue, 2α-methyl-(20S,23S)-epoxymethano-1α,25-dihydroxyvitamin D 3 (4a), in order to increase its transactivation potency. Here, we solved the crystal structures of the hVDR LBD in complex with the 4a (C23S) and its epimer 4b (C23R) and determined their correlation with specific biological outcomes.
- Antony, Pierre,Sigüeiro, Rita,Huet, Tiphaine,Sato, Yoshiteru,Ramalanjaona, Nick,Rodrigues, Luis Cezar,Mouri?o, Antonio,Moras, Dino,Rochel, Natacha
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scheme or table
p. 1159 - 1171
(2010/07/10)
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- Total synthesis of (+)-chinensiolide B via tandem allylboration/ lactonization
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(Chemical Equation Presented) The chinensiolides are a family of guaiane type α-methylene γ-lactone natural products recently isolated from Ixeris chinensis Nakai, a plant used in Chinese folk medicine. The first enantioselective total synthesis of (+)-chinensiolide B was accomplished in 15 steps for the longest linear sequence with an overall yield of 6.7% starting from inexpensive and readily available (R)-carvone. A highly stereoselective and E/Z-selective tandem allylboration/lactonization reaction between two highly functionalized partners was exploited as a key step. The synthesis also highlights several solutions to chemoselectivity issues arising from the reactive α-methylene γ-lactone. For instance, a ring-closing metathesis formed the requisite seven-membered ring in a chemoselective fashion while avoiding the reactivity of the conjugated α-methylene unit.
- Elford, Tim G.,Hall, Dennis G.
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scheme or table
p. 1488 - 1489
(2010/04/04)
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- Chiral building blocks from R-(-)-carvone: N-bromosuccinimidemediated addition-sceletal rearrangement of (-)-cis-carveol
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Synthetically valuable bicyclic blocks 5, 7 and 9 were prepared by the oxidative cleavage of the double bond of 4 with the RuCl3-NaIO4 system and O3.
- Valeev, Ruslan F.,Selezneva, Nataliya K.,Starikova, Zoya A.,Pankrat'ev, Evgenii Yu.,Miftakhov, Mansur S.
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scheme or table
p. 77 - 79
(2010/06/19)
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- VITAMIN D RECEPTOR ACTIVATORS AND METHODS OF MAKING
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The invention relates to compounds that are vitamin D receptor activators, compositions comprising such compounds, methods of using such compounds and compositions, processes for preparing such compounds, and intermediates obtained during such processes.
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Page/Page column 36
(2009/05/28)
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- Total synthesis of (-)-incarvilline and (-)-incarvillateine
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An enantioselective, concise total synthesis of (-)-incarvilline and (-)-incarvillateine has been achieved in longest linear 9 steps (24.3% overall yield) and in 11 steps (16.5% overall yield) from (-)-carvone, respectively. The present synthesis features a notable Favorskii rearrangement of the O-protected chlorohydrin derivative of (-)-carvone to construct four of the five contiguous stereocenters on the bicyclic piperidine moiety and DMAP-catalyzed esterification of incarvilline with α-truxillic acid anhydride to generate incarvillateine skeleton.
- Zhang, Fengying,Jia, Yanxing
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scheme or table
p. 6840 - 6843
(2009/12/06)
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- An improved asymmetric synthesis of malyngamide U and its 2′-epimer
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(Chemical Equation Presented) An accelerated and improved asymmetric synthesis of malyngamide U (1) and its 2′-epimer (2′-epi-1) was accomplished from readily available n-hexanal, ethanolamine and (R)-(-)-carvone. The key steps involveda Johnson-Claisen rearrangement in the synthesis of an unsaturated carboxylic acid 4 and an aldol reaction in the construction of the skeleton of 1 and 2′-epi-1. There are 13 steps in the synthesis, with a 2.7% overall yield for 1 and a 0.4% yield for 2′-epi-1.
- Feng, Jian-Peng,Shi, Zi-Fa,Li, Yang,Zhang, Jun-Tao,Qi, Xian-Liang,Chen, Jie,Cao, Xiao-Ping
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p. 6873 - 6876
(2008/12/22)
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- Facile epoxidation of α,β-unsaturated ketones with cyclohexylidenebishydroperoxide
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Cyclohexylidenebishydroperoxide was successfully used as the oxygen source for the oxidation of α,β-unsaturated ketones for the first time. The corresponding epoxides were obtained in excellent yields under the Weitz-Scheffer reaction conditions.
- Jakka, Kavitha,Liu, Jinyun,Zhao, Cong-Gui
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p. 1395 - 1398
(2007/10/03)
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- Opening of epoxide rings catalyzed by niobium pentachloride
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The behavior of several epoxides when treated with NbCl5 was studied. In general, the studied epoxides reacted rapidly with NbCl5, giving, in most cases, more than one product (chlorohydrins, products containing solvent residues, as well as rearrangement products). A detailed study was performed to verify the effects of the temperature (rt, 0°C, or -78°C) and of the NbCl5 molar concentration on the composition of the products, yield, and time required for the reactions. Copyright Taylor & Francis Group, LLC.
- Constantino, Mauricio Gomes,Lacerda Jr., Valdemar,Invernize, Paulo Roberto,Filho, Luiz Carlos Da Silva,Da Silva, Gil Valdo Jose
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p. 3529 - 3539
(2008/03/13)
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- Short new route to the chiral spiro-tetrahydrofuran subunit common to some terpenoids
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Synthetic strategy based on a stereoselective iodoetherification reaction of a carvone-derived hydroxyalkene unit has been developed for the asymmetric synthesis of the key spiro-tetrahydrofuran subunit common to some naturally occurring terpenoids. Copyright Taylor & Francis, Inc.
- Chattopadhyay, Shital K.,Karmakar, Swastik,Sarkar, Kaushik
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p. 2125 - 2132
(2007/10/03)
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- NOVEL INTERMEDIATES FOR SYNTHESIS OF VITAMIN D DERIVATIVES
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The present invention provides a novel intermediate for synthesizing vitamin D derivatives by using a less expensive material. That is, the present invention provides a compound which is synthesized by using carvone as a starting material and which is represented by the following formulae.
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Page/Page column 9; 14
(2008/06/13)
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- A novel boron trifluoride etherate mediated deep-seated rearrangement of an α,β-epoxyketone
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Acid catalysed reaction of carvone epoxide 2 resulted in dimeric products 3 and 4, in contrast to the expected ring contraction product. Reaction of β-methylcarvone epoxides 8 and 11 with acids furnished 2-acetyl-4- isopropenylcyclopentanones 9 and 14 containing a stereodefined quaternary carbon atom. On the other hand, the reaction of epoxides 8 and 11 with boron trifluoride etherate lacks the stereoselectivity and in addition, anti-epoxide 8 furnished lactone 18 via an unusual deep seated rearrangement.
- Srikrishna, Adusumilli,Ramasastry, Sripada S. V.
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p. 2973 - 2979
(2007/10/03)
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- Synthesis of (+)- and (-)-isocarvone
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The first synthesis of 5-isopropenyl-3-methyl-cyclohex-2-enone, (isocarvone) (2), in enantiomerically pure form is reported. Both enantiomers of 2 can be produced by manipulation of carboxylic acid 5, which is available from R-(-)-carvone (1). These materials provide new chiral building blocks that could be used in total synthesis of natural products and related optically active compounds.
- González, Miguel A.,Ghosh, Subhash,Rivas, Fatima,Fischer, Derek,Theodorakis, Emmanuel A.
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p. 5039 - 5041
(2007/10/03)
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- Stereoselective synthesis of enantiomerically pure, orthogonally protected 2-methylenecyclohexane-1,3,5-triols and 2,4,6-trihydroxycyclohexanones
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The triply silyl protected 2-methylenecyclohexane-1,3,5-triols 1a-c (C-1: tert-butyldimethylsilyl, TBDMS; C-3: trimethylsilyl, TMS; C-5: tert-butyldiphenylsilyl, TBDPS) were prepared from (R)-(-)-carvone in seven synthetic steps (overall yields: 29-53%). Ozonolysis in the presence of triethylamine yielded the triply protected 2,4,6-trihydroxycyclohexanones 2a-c (85%-quant.). The configuration of the products was proven by NOESY studies and by chemical correlation.
- Kirsch, Stefan,Bach, Thorsten
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p. 1827 - 1836
(2007/10/03)
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- A general, ring closure metathesis based enantiospecific approach to polyfunctional eudesmane, eremophilane and agarofuran sesquiterpenoids
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An enantiospecific and stereo- and functional group diversity oriented approach to eudesmane, eremophilane and agarofuran sesquiterpenoids from (-)-carvone has been devised. RCM has been employed as the key reaction to generate the highly functionalized eudesmane framework. Further elaboration of the eudesmane framework to agarofurans and biogenetic-type rearrangement to eremophilanes is outlined.
- Mehta, Goverdhan,Kumaran, R. Senthil
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p. 7055 - 7059
(2007/10/03)
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- Highly efficient epoxidation of α,β-unsaturated ketones by hydrogen peroxide with a base hydrotalcite catalyst prepared from metal oxides
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The base hydrotalcite, prepared from MgO and Al2O3, acted as a highly efficient catalyst for the epoxidation of α,β-unsaturated ketones using aqueous hydrogen peroxide as an oxidant. This heterogeneous epoxidation has the advantages of a high efficiency of H2O2 utilization without organic solvents, a simple workup procedure, and reusability of the hydrotalcite catalyst.
- Honma, Takayuki,Nakajo, Michiko,Mizugaki, Tomoo,Ebitani, Kohki,Kaneda, Kiyotomi
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p. 6229 - 6232
(2007/10/03)
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- Epoxidation of α,β-Unsaturated Ketones Using Hydrogen Peroxide in the Presence of Basic Hydrotalcite Catalysts
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The basic layered hydrotalcites have been used as catalysts for the epoxidation of α,β-unsaturated ketones in heterogeneous reaction media using hydrogen peroxide as an oxidant. A wide variety of α,β-unsaturated ketones were oxidized to the corresponding epoxyketones in excellent yields under mild reaction conditions. For example, 2-cyclohexen-1-one gave 2,3-epoxycyclohexanone in 91% yield at 40°C for 5 h with high efficiency in hydrogen peroxide. The catalytic activity of the hydrotalcites increased as the basicity of their surfaces increased. In the case of the epoxidation of less reactive substrates, adding a cationic surfactant such as n-dodecyltrimethylammonium bromide (DTMAB) to the above oxidation system accelerated the epoxidation reaction. These hydrotalcite catalysts were easily separated from the reaction mixture and were reusable.
- Yamaguchi, Kazuya,Mori, Kohsuke,Mizugaki, Tomoo,Ebitani, Kohki,Kaneda, Kiyotomi
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p. 6897 - 6903
(2007/10/03)
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- A new carvone based construction of the ring-A of taxoids
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A synthesis of the fully functionalized A-ring of taxoids from the commercially available monoterpenic chiron R-carvone is outlined. In this approach, regio- and stereoselective restructuring of alkyl substituents and functionalities is effected on the periphery while retaining the six membered core of carvone.
- Mehta, Goverdhan,Chattopadhyay, Shital K.,Umarye, Jayant D.
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p. 4881 - 4884
(2007/10/03)
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- A novel and enantioselective approach to the synthesis of cyclohexane carbocyclic nucleosides starting from (-)-carvone
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3,5-dihydroxy-4-(hydroxymethyl)-1-cyclohexanyl adenine has been synthesized starting from (-)-carvone. The adenine base was introduced via Mitsunobu reaction. Conformational analysis showed that the base still adopts the equatorial position at the expense of three axial substituents.
- Wang, Jing,Herdewijn, Piet
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p. 591 - 592
(2007/10/03)
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- Lithium naphthalenide induced reductive cleavage of α,β-epoxy ketones: An efficient procedure for the preparation of β-hydroxy ketones
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Lithium naphthalenide presents itself as a mild and efficient reagent for the cleavage of α,β-epoxy ketones to give the corresponding β-hydroxy ketones in good yields.
- Jankowska, Renata,Mhehe, George L.,Liu, Hsing-Jang
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p. 1581 - 1582
(2007/10/03)
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- Inverse phase transfer catalysis. III.- Optimization of the epoxidation reaction of α,β-unsaturated ketones by hydrogen peroxide
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The epoxidation of chalcone using hydrogen peroxide in the presence of a base in a two-phase medium system following the so-called Inverse Phase Transfer Catalysis (IPTC) process was investigated. Careful examination of various parameters including surfactant concentration, pH, H2O2 decomposition side-reactions and epoxide ring-opening, allowed us to determine optimal experimental conditions.
- Boyer, Bernard,Hambardzoumian, Araik,Roque, Jean-Pierre,Beylerian, Norair
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p. 6147 - 6152
(2007/10/03)
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- Enantioselective approach to the synthesis of cyclohexane carbocyclic nucleosides
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(R)-(-)-Carvone was used as starting material for the synthesis of a new series of 2-(hydroxymethyl)-cyclohexane-1,3-diol nucleosides. The enantioselective precursors of the nucleoside analogues were obtained via a stereo- and regioselective hydroboration reaction. The compounds have equatorial oriented base moieties despite the presence of three other axial substituents.
- Wang, Jing,Busson, Roger,Blaton, Norbert,Rozenski, Jef,Herdewijn, Piet
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p. 3051 - 3058
(2007/10/03)
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- Microwave Promoted Epoxidation of α,β-Unsaturated Ketones in Aqueous Sodium Perborate
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A series of α,β-unsaturated ketones has been treated with sodium perborate in water and 1,4-dioxane under microwave irradiation to produce α,β-epoxyketones in good yields.
- Sharifi, Ali,Bolourtchian, Mohammad,Mohsenzadeh, Farshid
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p. 668 - 669
(2007/10/03)
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- Bryostatin: A novel asymmetric synthesis of the C27-C34 fragment starting from (R)-carvone as chiral template
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(R)-Carvone is a suitable chiral template for the synthesis of differently protected (4S,6R,7R)-trihydroxy-1-octyne derivatives, the C27-C34 fragment of bryostatins. Also other potentially interesting chiral building blocks are described.
- De Brabander,Kulkarni,Garcia-Lopez,Vandewalle
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p. 1721 - 1724
(2007/10/03)
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- (R)-Carvone as chiral template for the synthesis of some polyols
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Some (4S,6R,7R) 4,6,7-trihydroxyheptyl derived building blocks have been obtained from (R)-carvone as the chiral template.A key-step is the Baeyer-Villiger oxidation of a suitable intermediate.
- Brabander, J. De,Kulkarni, B. A.,Garcia-Lopez, R.,Vandewalle, M.
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p. 665 - 670
(2007/10/03)
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- Efficient and versatile synthesis of A-ring precursors of 1α,25-dihydroxyvitamin D3 and analogues. Application to the synthesis of Lythgoe-Roche phosphine oxide
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An efficient, versatile synthesis of Lythgoe-Phosphine Oxide has been developed starting from l-carvene. The key steps are rupture of protected epoxide 7 to give dicarbonyl compound 8, preparation of vinylic triflate 2, and palladium-catalysed cyclization-carbonylation of vinylic triflate 2.
- Mourino, Antonio,Torneiro, Mercedes,Vitale, Cristian,Fernandez, Sara,Perez-Sestelo, Jose,Anne, Sofia,Gregorio, Carlos
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p. 4713 - 4716
(2007/10/03)
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- Practical epoxidation of α,β-unsaturated ketones with tetra-n-butylammonium peroxydisulfate
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α,β-Unsaturated ketones reacted with tetra-n-butylammonium peroxydisulfate in the presence of hydrogen peroxide and base in acetonitrile at 25 °C to give the corresponding epoxides in excellent yields.
- Kim, Yong Hae,Hwang, Je Pil,Yang, Seung Gak
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p. 3009 - 3012
(2007/10/03)
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- A versatile cobalt(II)-Schiff base catalyzed oxidation of organic substrates with dioxygen: Scope and mechanism
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Cobalt(II) complex 1a-f derived from Schiff bases act as efficient catalysts during the oxidation of wide range of organic substrates(e.g. alkenes, alcohols, benzylic compounds and aliphatic hydrocarbons) with dioxygen in the presence of aliphatic aldehydes or ketones or ketoesters. EPR studies on 1a-f complexes suggest that the aliphatic carbonyl compounds promote the formation of a cobalt(II)-superoxo species responsible for the oxidation of organic compounds. These studies also demonstrate the role of ligands on cobalt in controlling the chemoselectivity of these oxidations. A plausible mechanistic rational is also provided for these oxidations.
- Punniyamurthy,Bhatia, Beena,Reddy, M. Madhava,Maikap, Golak C.,Iqbal, Javed
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p. 7649 - 7670
(2007/10/03)
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- KF adsorbed on alumina effectively promotes the epoxidation of electron deficient alkenes by anhydrous t-BuOOH
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KF adsorbed on alumina (KF-Al2O3) has been studied in detail for the epoxidation of electron deficient alkenes with anhydrous t-BuOOH. Aqueous base sensitive functional groups survive the reagent. Cyclopentenones are oxidized in decent to quantitative yields without showing any observable aldol products. α,β,γ,δ-Dienones are regioselectively oxidized at the α,β-position. Unlike aqueous alkaline H2O2, KF-Al2O3 is non-stereospecific and offers a mixture of cis and trans oxides from most acyclic enones. Except for the oxidation of α,β-unsaturated lactones and for the difference in reaction rates, the present reagent is, in general, similar to the t-BuOOH-DBU combination.
- Yadav,Kapoor
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p. 3659 - 3668
(2007/10/03)
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- Total synthesis of (-)-Ampullicin and (+)-lsoampullicin two growth regulators from Ampulliferina sp. no. 27
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The growth regulators (-)-Ampullicin (1) and (+)-isoampullicin (2) have been synthesized utilizing carbaldehyde (25) as the chiral source and N-tertbutoxycarbonyl-3-methyl-2-(trimethylsiloxy)pyrrole (33) as the five-carbon homologative reagent. The synthesis of (1) and (2) is discussed in the context of retrosynthetic analysis. Carbaldehyde (25), has been prepared from both enantiomers of carvone, either (7) or (9), by application of a 15-step sequence with 4.7% and 5.4% overall yields respectively.
- Rico, Rosario,Bermejo, Francisco
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p. 7889 - 7892
(2007/10/02)
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- 1,8-diazabicyclo[5.4.0]undec-7-ene: A remarkable base in the epoxidation of α,β-unsaturated-δ-lactones and other enones with anhydrous t-BuOOH
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1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) has been studied for the epoxidation of electron deficient alkenes with anhydrous t-BuOOH (TBHP) in dichloroethane. Steric demands are higher than that for alkaline H2O2 DBU is recognised as a remarkable base in these oxidations as other bases such as triethyl amine, diisopropylethyl amine, and 1,4-diazabicyclo[2.2.2]octane (DABCO) are absolutely inefficient. DBU is effective in promoting the oxidation of α,β-unsaturated δ-lactones where most of conventional methods either fail or perform poor.
- Yadav,Kapoor
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p. 8573 - 8584
(2007/10/02)
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- Synthesis of the four epimeric tosylates of (5R)-2,3-epoxy-5-isopropenyl-cyclohexanol
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Described is the synthesis of the four optically pure epoxytosylates 5, 6, 9 and 12, each with four chiral centers determined, from a single starting material, (R)(-) carvone.
- Jones Jr.,Kover
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p. 3907 - 3921
(2007/10/03)
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- Hydrotalcite-Promoted Epoxidation of Electron-Deficient Alkenes with Hydrogen Peroxide
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A synthetic anionic clay, hydrotalcite (Mg/Al=2.8), promotes the epoxidation of electrondeficient alkenes with H2O2.With open-chain, α,β-unsaturated carbonyl compounds 3-hydroxy-1,2-dioxolanes are also obtained.
- Cativiela, Carlos,Figueras, Francois,Fraile, Jose M.,Garcia, Jose I.,Mayoral, Jose A.
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p. 4125 - 4128
(2007/10/02)
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- Stereoselective Favorskii Rearrangement of Carvone Chlorohydrin; Expedient Synthesis of (+)-Dihydronepetalactone and (+)-Iridomyrmecin
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(+)-Dihydronepetalactone and (+)-iridomyrmecin were synthesized from the stereoselective Favorskii rearrangement product of (+)-carvone chlorohydrin.
- Lee, Eun,Yoon, Cheol Hwan
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p. 479 - 482
(2007/10/02)
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