- 2-METHYLENE-3-ALKOXYCYCLOPENTANONES AS REACTIVE INTERMEDIATES AND THEIR APPLICATION TO THE SYNTHESES OF DIHYDROJASMONE, CIS-JASMONE AND (+/-)-JASMOLONE
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Dihydrojasmone and cis-jasmone were synthesized in high yields by the Michael addition of lithium di-n-butylcuprate and bromomagnesium di-1-butenylcuprate, respectively, to 2-methylene-3-methyl-3-methoxy-methyloxycyclopentanone. (+/-)-Jasmolone was also synthesized by the Michael addition of dialkenylcuprate to 2-methylene-3-methyl-3-methoxymethyloxy-4-ethoxyethyloxycyclopentanone.
- Takahashi, Takashi,Hori, Kimihiko,Tsuji, Jiro
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- Coupling Reactions of 1-Tributylstannyl-1-octen-3-ol Catalyzed by Palladium: The Synthesis of PGB1 and Coriolic Acid
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The palladium catalyzed coupling of (S)-E-1-tributylstannyl-1-octen-3-ol (3) with 2-(6-carbethoxyhexyl)-3-iodo-2-cyclopenten-1-one gave a 70percent yield of the (S)-ethyl ester of PGB1.Coriolic acid was synthesized in 75percent yield by coupling 3 with Z-10-iododecenoic acid, demonstrating the tolerance of this coupling reaction to the carboxylic acid function.
- Stille, J.K.,Sweet, Mark P.
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- Utilization of Basic Alumina in a One-Pot Synthesis of 1,4-Diketones, 1,4,7-Triketones, and Dihydrojasmone by Conjugate Addition of Nitroalkanes to Enones
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The one-pot synthesis of functionalized 1,4-diketones was achieved in good yields by conjugate addition of primary nitroalkanes to α,β-unsaturated carbonyl compounds on basic alumina without solvent, followed by in situ oxidation with 30percent aqueous hydrogen peroxide in methanol.The one-pot syntheses of 1,4,7-triketones and dihydrojasmone are also reported.
- Ballini, Roberto,Petrini, Marino,Marcantoni, Enrico,Rosini, Goffredo
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- Unusual endoperoxide isomerizations: a convenient entry into 2-vinyl-2-cyclopentenones from saturated fulvene endoperoxides
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An unusual peroxide base-promoted isomerization is uncovered. Saturated endoperoxides derived from fulvenes give rise to 2-vinyl-2-cyclopentenones upon treatment with DBU in CH2Cl2 in a one-pot reaction. This methodology is applied to a convenient synthesis of dihydrojasmone. Moreover, functional groups placed on the side chain at C-6 participate in the base-catalyzed isomerizations via conjugate attack at the enone moiety to give 2-cyclopentenones carrying oxygen heterocycles at C-2.
- Erden, Ihsan,?cal, Nüket,Song, Jiangao,Gleason, Cindy,G?rtner, Christian
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- A new synthesis of methyl 3-oxo-2-pentyl-1-cyclopentene-1-acetate
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The 92:8 equilibrium mixture of (±)-trans-methyl dihydrojasmonate (1) and its cis-isomer is transformed in 63% overall yield into the title compound 4 by epoxidation of the derived enol acetate 2 with peracetic acid/Na2CO3 in toluene and heating the resulting α-acetoxy epoxide 3 in MeOH in the presence of catalytic amounts of methanesulfonic acid.
- Crawford,Rautenstrauch,Uijttewaal
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- A SIMPLE SYNTHESIS OF DIHYDROJASMONE
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Acetalization of a γ-substituted α,β-unsaturated ketone, followed by acid hydrolysis gave a cyclopentenone.
- Liu, Shing-Hou
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- Development of modified Pauson-Khand reactions with ethylene and utilisation in the total synthesis of (+)-taylorione
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Two complementary Pauson-Khanol annulation protocols for use with the gaseous alkene, ethylene, are described. These N-oxide promoted reactions (10 examples) are shown to proceed under both mild autoclave condition or, more conveniently, at atmospheric pressure. The developed methodology has been utilised as the key transformation in the total synthesis of the sesquiterpene (+)-taylorione which has been realised in a good overall yield from readily available (+)-2-carene.
- Donkervoort, Johannes G.,Gordon, Alison R.,Johnstone, Craig,Kerr, William J.,Lange, Udo
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- α,β-Unsaturated ketones via copper(II) bromide mediated oxidation
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A protocol for effecting a rapid Saegusa-type oxidation of enol acetates is reported. This new method relies on the in situ elimination of an α-bromo intermediate to generate α,β-unsaturated ketones using copper(II) bromide. The methodology developed was applied to a range of substrates including a cyclohexanone, which could be directly converted to the corresponding phenol derivative. A catalytic system in which a non-masked ketone was successfully oxidised using substoichiometric CuBr2 was also developed as a proof of principle.
- Sharley, James S.,Collado Pérez, Ana María,Ferri, Estela Espinos,Miranda, Amadeo Fernandez,Baxendale, Ian R.
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- Cyclopentenones from γ-Nitroalkanoic Acids. Dihydrojasmone Synthesis
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Treatment of γ-nitroalkanoic acids with polyphosphoric acid or P2O5-MeSO3H led to cyclopentenones.
- Ho, Tse-Lok
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- A Novel Acetonylation of Carbonucleophiles via Palladium-Catalyzed Allylation with Isopropyl 2-Methylene-3,5-dioxahexyl Carbonate
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Carbonucleophiles such as malonate esters, β-keto esters, phenylacetate ester, and phenylacetonitrile were acetonylated in high yields by allylation with isopropyl (or methyl) 2-methylene-3,5-dioxahexyl carbonate (4b or 4a) in the presence of palladium-phosphine catalyst under neutral conditions, followed by acidic hydrolysis.Adopting this procedure dihydrojasmone (7) was prepared from ethyl 3-oxononanoate (6) in an overall yield of 72percent.
- Ikeda, Isao,Gu, Xue-Ping,Okuhara, Toshio,Okahara, Mitsuo
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- RUTHENIUM HYDRIDE-CATALYZED DOUBLE BOND MIGRATION OF 2,5-DIMETHOXY-2,5-DIHYDROFURANS. A NEW PROCESS FOR THE PREPARATION OF γ-KETOESTERS
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γ-Ketoesters are obtained in excellent yields by means of double bond migration of 2,5-dimethoxy-2,5-dihydrofurans mediated by a ruthenium hydride complex, HRuCl(PPh3)3(C6H5CH3) or HRuCl(CO)(PPh3)3, and subsequent hydrolysis in acidic media.
- Hirai, Kenji,Suzuki, Hiroharu,Kashiwagi, Hiroshi,Moro-Oka, Yoshihiko,Ikawa, Tsuneo
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- A New Synthesis of Vinyl Sulphides by Lewis Acid Promoted Reaction of trimethylsilanes with Trisubstituted Alkenes
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Treatment of the α0chloro-α-silyl sulphides (1) or (5) with trisubstituted alkenes (6) in the presence of SnCl4 gave the vinyl sulphides (7) or (8), the formation of which involves a carbenium ion rearrangement controlled by the silyl group.
- Ishibashi, Hiroyuki,Nakatani, Hiroshi,Sakashita, Hiroshi,Ikeda, Masazumi
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- Photo-Fries-type rearrangement of cyclic enamides. An efficient route to structurally diverse five-membered enaminones
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A simple, efficient and user-friendly protocol for the preparation of structurally diverse enaminones from enamides has been developed. The strategy is based on a photo-induced intramolecular Fries-type rearrangement. The photochemical transformation proceeds under mild reaction conditions, applies to a broad substrate range, is highly economic, and limits the amount of waste produced. The proposed methodology was used as a key step in the synthesis of dihydrojasmone an important fragrance compound.
- Furman, Bart?omiej,Szcze?niak, Piotr
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p. 1898 - 1901
(2022/02/19)
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- Synthesis of Pyrethroids and Jasmonoids through Palladium-Catalyzed Cross-Coupling Reactions
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The synthesis of jasmone and related jasmonoids and pyrethroids is described. These compounds play a defensive role in plants and share a common cyclopentenone core with variations in the side chains. Jasmone, cinerone, allylrethrone, and derivatives were synthesized through -allyl palladium cross-coupling of stannane derivatives. With selective hydrogenation, dihydrojasmone, and dihydrocinerone were also synthesized.
- Heguaburu, Viviana,Pandolfi, Enrique,Parpal, Florencia,Paullier, Ana Paula
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- Synthesis method of dihydrojasmonone
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The invention discloses a synthesis method of dihydrojasmonone, belongs to the technical field of perfume synthesis, aims to solve the problems that raw materials are difficult to prepare and high in price, and the fragrance of a product is impure, and relates to a method for synthesizing dihydrojasmonone by reacting halogenated n-hexane and magnesium chips under a solvent condition to generate an n-hexyl Grignard reagent under anhydrous and nitrogen protection, carrying out catalytic coupling on the n-hexyl Grignard reagent and acetyl propionyl chloride through vanadium trichloride to generate undecane-2,5-dione, and carrying out condensation ring closing on undecane-2,5-dione under an alkaline condition. In the synthesis route, the used raw materials are cheap and easy to obtain, and other auxiliary reagents are all industrial basic raw materials, so that the price is low; reaction steps are short, and reaction conditions are simple; and in addition, the reaction yield is relatively high and is kept at 64-72%, and the purity is relatively high and is kept at about 98%, so that the method is suitable for realizing industrial production and has relatively high application value.
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Paragraph 0040-0047
(2021/07/31)
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- Synthesis method of high-content dihydrojasmonic spice (by machine translation)
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The synthetic method comprises the following steps: 2 - octanol serving as a solvent and di-tert-butyl peroxide as an initiator, and refluxing to separate t-butyl alcohol and water, vacuum distillation to obtain 2 - octyl 2 - (3H) furanone, and then dehydrating and dehydrating 5 - methyl -5 - hexyl -2 -2 -5 - (3H) furanone molecules under the action of a solid acid catalyst to recover the dihydrojasmonic spice product after the reflux reaction is carried out 5 . The synthesis method provided by the invention has the advantages of relatively simple steps, no acid waste water generation and high total yield, and moreover, the content of the product and the dihydrojasmonone synthesized through the synthetic method provided by the invention is higher than 98% and above. (by machine translation)
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Paragraph 0018; 0030; 0038-0041
(2020/07/13)
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- Method for synthesizing dihydrojasmone under alkaline condition
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The invention discloses a method for synthesizing dihydrojasmone under an alkaline condition, which comprises the following steps of: adding alkali liquor into a reaction kettle provided with a mechanical stirrer, a water segregator and a reflux condenser pipe, uniformly stirring, heating, refluxing, dropwise adding methyl 3-oxo-2-pentyl-1-cyclopentene-1-acetate into a reaction kettle at the dropwise adding rate of 12-15 g/min, then carrying out a reaction process for 4-6 h under the reflux condition of 80-100 DEG C, carrying out standing and layering so that an organic phase 1 is obtained after a water phase is separated out, adding a sodium sulfate aqueous solution into the organic phase 1, stirring for 10-30 minutes, standing for layering, separating out a water phase to obtain an organic phase 2, carrying out reduced pressure distillation on the organic phase 2, and collecting fractions to obtain dihydrojasmones. Compared with the traditional process, the synthetic method has the advantages that the reaction conditions are simple, the dihydrojasmones can be synthesized under common heating reflux conditions, the synthetic steps are simple and convenient, the yield of the dihydrojasmones prepared by the synthetic method is high, and the purity of the prepared dihydrojasmones is high and can reach 99.5%.
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Paragraph 0026-0035
(2020/11/12)
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- Preparation method of low-cost dihydrojasmone
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The invention discloses a preparation method of low-cost dihydrojasmone. The preparation method includes the following steps of 1, chlorination, 2, dechlorination and 3, decarboxylation. Compared withconventional techniques, the preparation method of the low-cost dihydrojasmone has the advantages that raw materials are cheap and easy to obtain, auxiliary reagents are industrial basic raw materials, reaction conditions are simple, complex reaction conditions are not required, and the yield is high, so that the price is low and the industrial production is easily realized.
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Paragraph 0008; 0009
(2019/04/13)
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- DEHYDROGENATION REACTION
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The present invention relates to the field of organic synthesis and more specifically it concerns a process for the dehydrogenation of compound of formula (I) catalyzed by palladium (Pd0) in elemental metallic form.
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Page/Page column 11-12
(2018/04/02)
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- Chemo-Enzymatic Oxidative Rearrangement of Tertiary Allylic Alcohols: Synthetic Application and Integration into a Cascade Process
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A chemo-enzymatic catalytic system, comprised of Bobbitt's salt and laccase from Trametes versicolor, allowed the [1,3]-oxidative rearrangement of endocyclic allylic tertiary alcohols into the corresponding enones under an Oxygen atmosphere in aqueous media. The yields were in most cases quantitative, especially for the cyclopent-2-en-1-ol or the cyclohex-2-en-1-ol substrates without an electron withdrawing group (EWG) on the side chain. Transpositions of macrocyclic alkenols or tertiary alcohols bearing an EWG on the side chain were instead carried out in acetonitrile by using an immobilized laccase preparation. Dehydro-Jasmone, dehydro-Hedione, dehydro-Muscone and other fragrance precursors were directly prepared with this procedure, while a synthetic route was developed to easily transform a cyclopentenone derivative into trans-Magnolione and dehydro-Magnolione. The rearrangement of exocyclic allylic alcohols was tested as well, and a dynamic kinetic resolution was observed: α,β-unsaturated ketones with (E)-configuration and a high diastereomeric excess were synthesized. Finally, the 2,2,6,6-tetramethyl-1-piperidinium tetrafluoroborate (TEMPO+BF4?)/laccase catalysed oxidative rearrangement was combined with the ene-reductase/alcohol dehydrogenase cascade process in a one-pot three-step synthesis of cis or trans 3-methylcyclohexan-1-ol, in both cases with a high optical purity. (Figure presented.).
- Brenna, Elisabetta,Crotti, Michele,De Pieri, Matteo,Gatti, Francesco G.,Manenti, Gabriele,Monti, Daniela
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p. 3677 - 3686
(2018/06/04)
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- Iodine-Catalyzed Iso-Nazarov Cyclization of Conjugated Dienals for the Synthesis of 2-Cyclopentenones
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Molecular iodine was identified as an efficient catalyst for the cycloisomerization of conjugated dienals to substituted 2-cyclopentenones. DFT calculations suggested an unexpected concerted character for this cyclization.
- Marsili, Lucía A.,Pergomet, Jorgelina L.,Gandon, Vincent,Riveira, Martín J.
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supporting information
p. 7298 - 7303
(2018/11/25)
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- METHODS OF PREPARING a,?-UNSATURATED OR a-HALO KETONES AND ALDEHYDES
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Copper(II) bromide mediated oxidation of acylated enol and use of the reaction in the synthesis of α,β-unsaturated or α-bromo ketones or aldehydes are disclosed. The method provides an efficient and practical process for manufacturing dehydrohedione (DHH) and many other versatile α,β-unsaturated or α-bromo ketones or aldehydes in large scales to avoid using precious metal compounds.
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Paragraph 0087; 0116; 0117; 0120; 0121
(2017/07/14)
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- Oxidative conversion of silyl enol ethers to α,β-unsaturated ketones employing oxoammonium salts
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The oxidative conversion of silyl enol ethers to α,β-unsaturated ketones using a less-hindered class of oxoammonium salts (AZADO +BF4-) is described. The reaction proceeds via the ene-like addition of oxoammonium salts to silyl enol ethers.
- Hayashi, Masaki,Shibuya, Masatoshi,Iwabuchi, Yoshiharu
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supporting information; experimental part
p. 154 - 157
(2012/02/16)
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- Highly selective hydrogenation of carbon-carbon multiple bonds catalyzed by the cation [(C6Me6)2Ru2(PPh 2)H2]+: Molecular structure of [(C 6Me6)2Ru2(PPh2)(CHCHPh)H] +, a possible intermediate in the case of phenylacetylene hydrogenation
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The dinuclear cation [(C6Me6)2Ru 2(PPh2)H2]+ (1) has been studied as the catalyst for the hydrogenation of carbon-carbon double and triple bonds. In particular, [1][BF4] turned out to be a highly selective hydrogenation catalyst for olefin functions in molecules also containing reducible carbonyl functions, such as acrolein, carvone, and methyljasmonate. The hypothesis of molecular catalysis by dinuclear ruthenium complexes is supported by catalyst-poisoning experiments, the absence of an induction period in the kinetics of cyclohexene hydrogenation, and the isolation and single-crystal X-ray structure analysis of the tetrafluoroborate salt of the cation [(C6Me6)2Ru2(PPh 2)-(CHCHPh)H]+ (2), which can be considered as an intermediate in the case of phenylacetylene hydrogenation. On the basis of these findings, a catalytic cycle is proposed which implies that substrate hydrogenation takes place at the intact diruthenium backbone, with the two ruthenium atoms acting cooperatively in the hydrogen-transfer process.
- Tschan, Mathieu J.-L.,Suess-Fink, Georg,Cherioux, Frederic,Therrien, Bruno
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p. 292 - 299
(2007/10/03)
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- PROCESS FOR PRODUCTION OF SUBSTITUTED CYCLOPENTANONE
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A substituted cyclopentanone represented by the formula (2) can be produced by hydrogenating the double bond in a compound represented by the formula (1) in the presence of a transition metal catalyst by using a carboxylic acid or a specific concentration of a carboxylic acid ester as a solvent. This process can produce a substituted cyclopentanone which is useful as an jasmine-flavored fragrance, an intermediate in the production of the fragrance or the like, in a simple and inexpensive manner at a high cis-form ratio; (1) wherein R1 and R2 represent a substituent having 1 to 8 carbon atoms; and (2) wherein R3 and R4 represent a substituent having 1 to 8 carbon atoms, may be the same as R1 and R2, and may be the same as each other.
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Page/Page column 76
(2008/06/13)
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- Highly chemoselective hydrogenation method using novel finely dispersed palladium catalyst on silk-fibroin: Its preparation and activity
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A palladium-fibroin complex (Pd/Fib) was prepared by soaking silk-fibroin in MeOH solution of Pd(OAc)2 for 2 days (under Ar atmosphere) - 4 days (under air). Pd(OAc)2 was gradually absorbed by fibroin and the rapid reduction of fibroin conjugated Pd(OAc)2 proceeded with MeOH as a reductant at room temperature to be the Pd(0) complex. Pd/Fib catalyzed chemoselective hydrogenation of acetylenes, olefins and azides in the presence of aromatic ketones and aldehydes, halides, N-Cbz protective groups and benzyl esters which are readily hydrogenated using Pd/C or Pd/C(en) as a catalyst.
- Ikawa, Takashi,Sajiki, Hironao,Hirota, Kosaku
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p. 2217 - 2231
(2007/10/03)
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- Rhodium-catalyzed intramolecular hydroacylation of 5- and 6-alkynals: Convenient synthesis of α-alkylidenecycloalkanones and cycloalkenones
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A novel intramolecular hydroacylation of 5- and 6-alkynals leading to α-alkylidenecycloalkanones was accomplished by using cationic a rhodium(I)/BINAP complex. For all cyclizations described, a single (E)-olefin isomer was obtained. At elevated temperature, hydroacylation and double bond migration of 5- and 6-alkynals proceeded in a one-pot reaction to give cycloalkenones. An intramolecular hydroacylation of a 7-alkynal was unsuccessful. This method represents an attractive new route to highly functionalized α-alkylidenecycloalkanones and cycloalkenones.
- Takeishi, Kenzo,Sugishima, Koudai,Sasaki, Kaori,Tanaka, Ken
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p. 5681 - 5688
(2007/10/03)
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- Unexpected reaction of 2,3-epoxy sulfonates: Novel formation of two enones with reversed substituents at α- and β-positions from the single isomer
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The 2,3-epoxy sulfonates gave two types of enones with reversed substituents at the α- and β-positions under neat and weakly acidic conditions. The reaction mechanism is also discussed.
- Fujioka, Hiromichi,Ohba, Yusuke,Futamura, Junko,Kita, Yasuyuki
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p. 453 - 462
(2007/10/03)
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- The rearrangement of 2,3-epoxysulfonates and its application to natural products syntheses: Formal synthesis of (-)-aphanorphine and total syntheses of (-)-α-herbertenol and (-)-herbertenediol
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The Lewis acid treatment of 2,3-epoxysulfonates with 2,3-dialkyl substituents or 2-alkyl-3-aryl substituents produced the rearrangement products via C3-cleavage of the oxirane ring in high yields. On the other hand, 2-aryl-3-alkyl-2,3-epoxysulfonates produced the products via C2-cleavage of the oxirane ring. The sulfonyloxy groups of the α-sulfonyloxy ketones, having a chiral benzylic quaternary carbon center obtained by the rearrangement of 2-alkyl-3-aryl-2,3-epoxysulfonates, were reductively eliminated to give the ketones with a chiral benzylic quaternary carbon center. The method was applied to the formal synthesis of (-)-aphanorphine and total syntheses of (-)-α-herbertenol and (-)-herbertenediol.
- Kita, Yasuyuki,Futamura, Junko,Ohba, Yusuke,Sawama, Yoshinari,Ganesh, Jnaneshwara K.,Fujioka, Hiromichi
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p. 5917 - 5924
(2007/10/03)
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- Compounds having protected hydroxy groups
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The present invention relates to compounds with protected hydroxy groups of formula (I) These compounds are precursors for organoleptic agents, such as fragrances, and masking agents and for antimicrobial agents. When activated, the compounds of formula (I) are cleaved and form one or more organoleptic and/or antimicrobial compounds.
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- Compounds having protected hydroxy groups
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The present invention relates to compounds with protected hydroxy groups of formula (I) These compounds are precursors for organoleptic agents, such as fragrances, and masking agents and for antimicrobial agents. When activated, the compounds of formula (I) are cleaved and form one or more organoleptic and/or antimicrobial compounds.
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- Precursors for fragrant ketones and fragrant aldehydes
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The present invention refers to fragrance precursors of formula I for a fragrant ketone of formula II and one or more fragrant aldehydes or ketones of formula III and IV, These fragrance precursors are useful in perfumery, especially in the fine and functional perfumery.
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- Beta-ketoester compounds
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The beta-ketoesters of formula I are useful as precursors for organoleptic compounds, especially for flavors, fragrances and masking agents and antimicrobial compounds.
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- Ketone precursors for organoleptic compounds
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The invention discloses ketones of formula I: wherein, Y is an optionally substituted alkyl, cycloalkyl, or cycloalkylalkyl, wherein each alkyl group is straight or branched and each alkyl and cycloalkyl group is saturated or unsaturated; R1is hydrogen or a C1-6alkyl group that is substituted, saturated or unsaturated, straight or branched; A is a chromophoric substituted aromatic ring or ring system; n is an integer; and with the proviso that formula I is not 2-ethoxy-1-phenyl-ethanone. These compositions are useful for the delivery of organoleptic compounds, especially of flavors, fragrances, masking agents and antimicrobial compounds.
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- A novel tandem [2 + 2] cycloaddition-Dieckmann condensation with ynolate anions. Efficient synthesis of substituted cycloalkenones and naphthalenes via formal [n + 1] cycloaddition
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A novel tandem [2 + 2] cycloaddition-Dieckmann condensation via ynolate anions is described. Ynolate anions are useful for the formation of reactive β-lactone enolates via a pathway not involving the enolization of the corresponding β-lactones. The [2 + 2] cycloaddition of ynolate anions with δ- or σ-keto esters, followed by Dieckmann condensation, gives bicyclic β-lactones, which are easily decarboxylated to produce synthetically useful 2,3-disubstituted cyclopentenones and cyclohexenones in one pot. This tandem reaction was applied to a novel, one-pot synthesis of highly substituted naphthalenes.
- Shindo,Sato,Shishido
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p. 7818 - 7824
(2007/10/03)
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- A three-component coupling approach to cyclopentanoids
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A new approach to 2,3-disubstituted cyclopentenones has been developed. This approach consists of a two-step protocol involving the cyclization of a Z-vinyl bromide under Barbier type conditions to form a cyclopentenol, which is then oxidatively rearranged to generate the cyclopentenone. The Z-vinyl bromide is in turn derived from a ruthenium catalyzed three-component coupling of an alkyne, an enone, and a HBr equivalent. A range of 2,3-disubstituted cyclopentenones has been generated, including short syntheses of jasmone and dihydrojasmone. Further applicability of this strategy is shown in the total syntheses of tetrahydrodicranenone B, rosaprostol, and a selective COX-2 inhibitor.
- Trost,Pinkerton
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p. 7714 - 7722
(2007/10/03)
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- Synthesis of vinyl nonaflates derived from β-ketoesters, 1/4 b-diketones or α-diketones and their palladium-catalyzed cross-coupling reactions with organozinc halides
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Cyclic and acyclic β-ketoesters 4, a typical cyclic α-diketone 5 and a typical cyclic β-diketone 6 were converted to the corresponding vinyl nonaflates of general formula 7, 8 and 9, respectively, by reaction with 1.2- 1.5 equiv of NaH in DMF at 20-55 °C followed by treatment with 1.15-1.30 equiv of perfluoro-1-butanesulfonyl fluoride at 20 °C. These vinyl nonaflates, which were purified by MPLC on silica gel, proved to be excellent electrophiles in Pd-catalyzed cross-coupling reactions with aryl-, 1-alkynyl- and alkylzinc chlorides. A variety of cyclic and acyclic tetrasubstituted α,β-unsaturated esters which included stereoisomerically pure compounds, a 2-substituted 3-aryl-2-cyclopentenone and naturally-occurring dihydrojasmone were cleanly synthesized by these smooth and selective cross-coupling reactions.
- Bellina, Fabio,Ciucci, Donatella,Rossi, Renzo,Vergamini, Piergiorgio
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p. 2103 - 2112
(2007/10/03)
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- Reaction of cyclic α-hydroxy epoxides with a strong base: A new 1,2-rearrangement, evidence for a carbenoid pathway
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Several substituted five- and six-membered cyclic α,β-unsaturated ketones are readily available by treatment of the corresponding α-hydroxy epoxides with an organolithium reagent. The reaction involves a new carbenoid 1,2-alkyl rearrangement. Evidence for the carbenoid intermediate has been obtained by an intramolecular trapping of the highly reactive species.
- Doris, Eric,Dechoux, Luc,Mioskowski, Charles
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p. 12700 - 12704
(2007/10/03)
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- Chemoselective conversion of conjugated nitroalkenes into ketones by sodium borohydride-hydrogen peroxide: A new synthesis of 4-oxoalkanoic acids, dihydrojasmone and (±)exo-brevicomin
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A new, simple, cheap, and practical procedure for the direct transformation of α,β-unsaturated nitroalkenes into ketones has been realized by the NaBH4/H2O2 system. By this method, other functional groups such as C-C double bonds, ketals or aromatic nitro groups were preserved. Application of this methodology to the preparation of 4-oxoalkanoic acids, dihydrojasmone, and (±)-exobrevicomin is also reported.
- Ballini,Bosica
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p. 723 - 726
(2007/10/02)
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- Oxidation of Ethers by NO3(radical) Generated from NO3- with Anodic Oxidation
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A radical NO3 generated by anodic oxidation of NO3- was found to be an effective species to the oxidation of ethers to the corresponding carboxylic acids and ketones, and this reaction was successfully applied to the synthesis of dihydrojasmone.
- Shono, Tatsuya,Yamamoto, Yoshinari,Takigawa, Katsuya,Maekawa, Hirofumi,Ishifune, Manabu,Kashimura, Shigenori
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p. 1045 - 1048
(2007/10/02)
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- Catalytic Reaction. 1. Catalytic 1,4-Hydrogenation of α,β-Unsaturated Aldehydes and Ketones using SC-1 Nickel Boride
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Ex-situ generated Sc-1 nickelboride (SC-1 Ni2B), prepared by refluxing nickel chloride and sodium borohydride in methanol, is used in the selective 1,4-hydrogenation of α,β-unsaturated ketones and aldehydes at one atmospheric pressure.Previous studies of in-situ generated Ni2B have had the disadvantage of the undesirable side reaction of sodium borohydride with the various functional groups.In contrast, our catalyst cleanly gives the corresponding saturated aldehyde or ketone with no detectable amounts of saturated alcohol.Furthermore, the degree of substitution of the double bond plays a significant role in the rate of hydrogenation.While unsaturated carbonyl compounds containing di- and tri- substituted duoble bonds are readily hydrogenated, tetrasubstituted double bond containing carbonyl compounds are highly unreactive.
- Belisle, Christopher M.,Young, Yvette M.,Singaram, Bakthan
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p. 5594 - 5598
(2007/10/02)
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- SIMPLE PREPARATION OF 3-METHYL-2-PENTYL-2-CYCLOPENTEN-1-ONE (DIHYDROJASMONE)
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A two-step method has been developed for the preparation of 2,5-undecanedione, which is a reported precursor of dihydrojasmone, by the condensation of heptanoyl chloride and methallyl chloride and subsequent reaction of the product, 1,2-dichloro-2-methyl-4-decanone, with sodium methylate in methanol with subsequent acid work-up of the reaction mixture.
- Sorokin, V. L.,Kulinkovich, O. G.
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p. 930 - 932
(2007/10/02)
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- Electroorganic Chemistry. 140. Electroreductively Intra- and Intermolecular Couplings of Ketones with Nitriles
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Electroreduction of γ- and δ-cyano ketones in i-PrOH with Sn cathode gave α-hydroxy ketones and their dehydroxylated ketones as the intramolecularly coupled products.Guaiazulene, (-)-valeranone, polyquinanes, dihydrojasmone, methyl dihydrojasmonate, and rosaprostol have been synthesized by utilizing this electroreductive intramolecular coupling of γ- and δ-cyano ketones in one of the key steps.Similarly, electroreduction of a mixture of ketone and nitrile gave the corresponding intermolecularly coupled product.The product obtained by the electroreductive intermolecular coupling of (+)-dihydrocarvone with acetonitrile has been found to be the precursor of an effective chiral ligand for the enantioselective addition of diethylzinc to aldehydes.
- Shono, Tatsuya,Kise, Naoki,Fujimoto, Taku,Tominaga, Naoto,Morita, Hiroshi
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p. 7175 - 7187
(2007/10/02)
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- Synthesis of 2,3,5-trisubstituted-2-cyclopentenones via base induced cyclization of alpha-chloro unsaturated ketones
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2,3,5-trisubstituted-2-cyclopentenones or 2,3-disubstituted-2-cyclopentenones (such as cis-jasmone) are prepared by contacting a 3-chloro-3,4-disubstituted-4-pentene-2-one with a strong base. Methods of preparing the reactants are also disclosed.
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- A NEW SYNTHESIS OF DIHYDROJASMON
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Strictly controlled hydrolysis of 5-methylene-4,5-dihydrofurans 3 allows an efficient approach to 2-acetonyl-1,3-dicarbonyl compounds 4, key intermediates in the synthesis of cyclopentenone derivatives.
- Antonioletti, Roberto,Bonadies, Francesco,Scettri, Arrigo
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p. 233 - 234
(2007/10/02)
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- Base-Induced Cyclization of α-Chloro- β,γ-Unsatured Ketones. Facile Synthesis of Tri- and Tetrasubstituted 2-Cyclopenten-1-ones
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Base-induced cyclization of fully substituted α-chloro β,γ-unsatured ketones results in substituted cyclopentenones.Potassium tert-butoxyde, lithium diisopropylamide, sodium hydroxide, and ammonium hydroxide can be used as the base for this process.In the case of ammonium hydroxide , it is proposed that initial formation of an enamine is followed by an intramolecular SN2'reaction of the enamine carbon.For all other bases, the reaction most likely proceeds through a ketone enolate.Application of this novel cyclization has been extended to the synthesis of several 2,3-substituted, 2,3,5-trisubstituted, and 2,3,5,5-tetrasubstituted 2-cyclopenten-1-ones.
- Mathew, Jacob
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p. 713 - 716
(2007/10/02)
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- Regioselectivity of Rhodium(II)-Catalyzed Decomposition of 1-Alkyl-1-(diazoacetyl)alkenes. Synthesis of 2-Alkyl-2-cyclopentenones and 2-Alkylidenecyclopentanones
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The synthesis of 1-alkyl-1-(diazoacetyl)alkenes and their dirhodium tetraacetate catalyzed transformation into 2-cyclopentenones and 2-alkylidenecyclopentanones are described.The competitive, intramolecular carbon-hydrogen insertion at two γ centers is discussed.
- Ceccherelli, Paolo,Curini, Massimo,Marcotullio, Maria Carla,Rosati, Ornelio,Wenkert, Ernest
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p. 7065 - 7070
(2007/10/02)
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- Process for preparing oxocyclopentene derivatives
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A process for preparing oxocyclopentenes of the formula: STR1 wherein R1 is hydrogen, lower alkyl or lower alkenyl and R2 is hydrogen, lower alkyl, lower alkenyl, lower alkynyl, substituted or unsubstituted aryl, ar(lower)alkyl, thienyl or cycloalkyl, which comprises subjecting a furan-carbinol of the formula: STR2 wherein R1 is as defined above and R3 is hydrogen, lower alkyl, lower alkenyl, lower alkynyl, substituted or unsubstituted aryl, ar(lower)alkyl, thienyl or cycloalkyl to rearrangement, subjecting the resultant hydroxycyclopentenone of the formula: STR3 wherein R1 and R3 are each as defined above to hydrogenation and subjecting the resulting hydroxycyclopentanone of the formula; STR4 wherein R1 and R2 are each as defined above to dehydration.
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- ELECTROREDUCTIVE INTRAMOLECULAR COUPLING OF γ- AND δ-CYANOKETONES
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Electroreduction of γ- and δ-cyanoketones in i-PrOH gave cyclized products α-hydroxyketones and their dehydroxylated ketones, and this reaction was applied to the synthesis of dihydrojasmone, methyl dihydrojasmonate, and Rosaprostol.
- Shono, Tatsuya,Kise, Naoki
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p. 1303 - 1306
(2007/10/02)
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- Syntesis of 2-Cycloalken-1-ones
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The bromination of 2-alkyl- and 2-phenyl-1-cycloalkanones with N-bromosuccinimide and subsequent dehydrobromination with aniline gave the corresponding 2-cycloalken-1-ones.
- Shimazaki, Makoto,Huang, Zhi-Hui,Goto, Mikiko,Suzuki, Noriko,Ohta, Akihiro
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p. 677 - 678
(2007/10/02)
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- An Effective and Selective Conjugate Propargylation Reaction of Stannylallenes to α,β-Unsaturated Carbonyl Compounds and α-Nitro Olefins
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Stannylallenes (1) reacted with α,β-unsaturated carbonyl compounds and α-nitro olefins in the presence of TiCl4 to give the corresponding conjugate propargylation products.Thus, the reaction of 1 with cyclic and acyclic α,β-unsaturated carbonyl compounds (2) gave β-propargylic ketones (3) in high yields.With α-nitro olefins (4), two types of products, β-propargylic nitroalkanes (5) and α-propargylic ketones (6), were obtained selectively depending on the presence or absence of the α-substituent of 4.Transformation of the products (6) to cyclopentenone derivatives (10 and 12) are also described.
- Haruta, Jun-ichi,Nishi, Koichi,Matsuda, Satoshi,Akai, Shuji,Tamura, Yasumitsu,Kita, Yasuyuki
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p. 4853 - 4859
(2007/10/02)
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- A Novel Route to Substituted Cyclopent-2-en-1-one; Application to the Synthesis of cis-Jasmone and Dihydrojasmone
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A short and efficient synthesis of cis-jasmone and dihydrojasmone has been achieved by the reaction of sulphur-stabilized carbanions with ethyl 2-chloro-2,3-dialkylbut-3-enoates.
- Mathew, Jacob,Alink, Ben
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p. 684 - 686
(2007/10/02)
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- Syntheses of Jasmone, Jasmonic Acid and some Analogues from Alkyne-cobalt Complexes via the Khand Reaction.
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The Khand reactions of the hexacarbonyldicobalt complexes of 2-octyne and of Z-oct-5-en-2-yne with ethylene lead directly to jasmone and dihydrojasmone. 2-Pentyl- and Z-2-pentenylcyclopent-2-en-1-one, known intermediates in the synthesis of jasmonic and dihydrojasmonic acid or their esters, have been obtained similarly from 1-heptyne and hept-4-en-1-yne respectively.These and related cyclopentenones have been converted into new analogues of methyl jasmonate, of interest as potential plant growth regulators.
- Billington, David C.,Bladon, Peter,Helps, I. Malcolm,Pauson, Peter L.,Thomson, William,Willison, Debra
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p. 2601 - 2623
(2007/10/02)
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