- 1,2-Bisanionic coupling approach to 2,3-disubstituted cyclopentenols and cyclopentenones
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We describe a new approach to 2,3-disubstituted cyclopentenols and cyclopentenones through two consecutive regioselective additions of equal or different electrophiles to a cyclopentene bisanionic synthon. Indeed, on exposure to BuLi, 3-bromo-2-iodocyclopent-2-enol O-TBS ether undergoes iodine-lithium permutation with complete regioselectivity. Successive reaction of the monolithium anion with different C(sp2)- and C(sp 3)-electrophiles affords the corresponding 2-substituted-3- bromocyclopentenol derivative. Subsequent bromo-lithium exchange with t-BuLi, followed by reaction with an equal or different electrophile, affords the desired 2,3-disubstituted cyclopentenol.
- Luparia, Marco,Vadala, Alessandro,Zanoni, Giuseppe,Vidari, Giovanni
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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 of Diketones, Ketoesters, and Tetraketones by Electrochemical Oxidative Decarboxylation of Malonic Acid Derivatives: Application to the Synthesis of cis-Jasmone
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Disubstituted malonic acid derivatives are smoothly converted into diketones and ketoesters in good to excellent yield (68% to 91%) under electrochemical conditions. The scope can be extended to transform trisubstituted bis-malonic acids into tetraketones in 77% to 86% yield. The new method was applied to the total synthesis of cis-jasmone.
- Ma, Xiaofeng,Dewez, Damien F.,Du, Le,Luo, Xiya,Markó, István E.,Lam, Kevin
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- Synthesis of Diketones, Ketoesters, and Tetraketones by Electrochemical Oxidative Decarboxylation of Malonic Acid Derivatives: Application to the Synthesis of cis-Jasmone
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Disubstituted malonic acid derivatives are smoothly converted into diketones and ketoesters in good to excellent yield (68% to 91%) under electrochemical conditions. The scope can be extended to transform trisubstituted bis-malonic acids into tetraketones in 77% to 86% yield. The new method was applied to the total synthesis of cis-jasmone.
- Ma, Xiaofeng,Du, Le,Luo, Xiya,Markó, István E.,Dewez, Damien F.,Lam, Kevin
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p. 12044 - 12055
(2019/03/01)
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- Ti-Crossed-Claisen condensation between carboxylic esters and acid chlorides or acids: A highly selective and general method for the preparation of various β-keto esters
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Ti-crossed-Claisen condensation between a 1:1 mixture of carboxylic esters and acid chlorides promoted by TiCl4-Bu3N-N-methylimidazole proceeded successfully to give various β-keto esters in good yields with excellent selectivities (19 examples, ～48-95% yield; cross/self-selectivity = ～96/4-99/1). The present method was extended to the condensation between a 1:1 mixture of carboxylic acids and carboxylic esters (six examples, ～70-92% yield; cross/self-selectivity = ～91/9-99/1). To demonstrate the utility of the present two Ti-crossed-Claisen condensations, we performed a couple of efficient short-step syntheses of two natural, representative, and useful perfumes, cis-jasmone and (R)-muscone. Copyright
- Misaki, Tomonori,Nagase, Ryohei,Matsumoto, Kunshi,Tanabe, Yoo
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p. 2854 - 2855
(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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- Tandem Thermal Reactions for the Synthesis of Jasmonoids
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A tandem reaction tactic for the preparation of a jasmonoid intermediate consists of pyrolysis of a spiroannulated cyclopentanone. The thermal decomposition actually involves a retro-Diels-Alder reaction and a homo-1,5-hydrogen shift with cleavage of the cyclopropane unit.
- Ho, Tse-Lok,Shyu, Kuo-Feng
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p. 319 - 321
(2007/10/03)
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- Photoinduced Electron Transfer Reactions of α-Cyclopropyl- And α-Epoxy Ketones. Tandem Fragmentation-Cyclization to Bi-, Tri-, and Spirocyclic Ketones
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Reductive photoinduced electron transfer (PET) reactions have been performed with various bicyclic a-cyclopropyl-substituted ketones and tertiary amines. The reaction resulted in a regioselective cleavage of one cyclopropyl bond under formation of an exocyclic radical with an endocyclic enolate unit. In the case of bicyclic ketones with an unsaturated side chain, various bicyclic, spirocyclic, and tricyclic products are accessible via radical cyclization, depending on the position of the alkenyl substituent. In addition to triethylamine, W-silylated amines have also been used as electron donors, leading to a variety of compounds, among them are silylated fragmentation products, indicating that a proton is transferred from not only the amine radical cation but also the cationic silyl group. The intramolecular Paternoe-Buechi reaction has also been studied for cyclopropane derivatives of the jasmone type leading to tetracyclic oxetanes. Finally, α-epoxy-substituted ketones have been investigated under PET conditions, yielding ring-opened products.
- Kirschberg, Thorsten,Mattay, Jochen
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p. 8885 - 8896
(2007/10/03)
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- Cyclopent-2-en-1-ones from [3 + 2]-annulation of 3-ethoxycarbonyl-2-propenylidene(triphenyl)phosphorane and glyoxals: Synthesis of cis-jasmone
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3-Ethoxycarbonyl-2-propenylidene(triphenyl)phosphorane (2) reacted with glyoxal monohydrates (5) to give 2-substituted 5-ethoxycarbonylcyclopent-2-en-1-ones (6) by [3 + 2]-annulation reaction in the presence of a base. Compounds 6 were easily converted to 2-substituted cyclopent-2-en-1-ones by deethoxycarbonylation. An application of the annulation to synthesis of cis-jasmone is also described.
- Islam, Md. Saiful,Kawano, Tomikazu,Hatanaka, Minoru,Ueda, Ikuo
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p. 5735 - 5738
(2007/10/03)
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- Synthesis of cis-Jasmone
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cis-Jasmone 1, an important olfactive ingredient of jasmine flower oil, was synthesized by starting from methyl 3-formylpropionate 2 in a 24 percent overall yield in 7 steps.
- Tsukasa, Hidetaka
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p. 1181 - 1182
(2007/10/02)
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- 2,3-Dihalo-1-(phenylsulfonyl)-1-propenes as Versatile Reagents for the Synthesis of Annulated Furans and Cyclopentenones
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2,3-Dihalo-1-(phenylsulfonyl)-1-propenes (DBP and DIP) are conveniently prepared by treating 1-(phenylsulfonyl)-1,2-propadiene with the appropriate halogen.These novel reagents undergo reaction with a variety of simple β-dicarbonyl anions to give substituted and annulated furans.When the reaction is carried out in polar solvents, 2,3,4-trisubstituted furans are formed.The reaction proceeds by an initial addition-elimination of the carbanion onto the vinyl carbon of the unsaturated sulfone which is followed by intramolecular ring closure on the enolate oxygen atom.When sodium methoxide is used as the base, the initially produced adduct undergoes deacylation and subsequent cyclization to give a 2,4-disubstituted furan.The synthetic utility of the method is demonstrated by a synthesis of (R)-menthofuran.Treatment of DIP with various trimethylsilyl enol ethers in the presence of silver tetrafluoroborate give alkylation products derived from SN2 displacement of the terminal halide.These compounds readily cyclize with base to produce an isomeric set of furans.Anions derived from 1,3-dicarbonyls substituted in the C-2 position are found to induce a complete reversal in the mode of ring closure.The major products obtained are 3--substituted cyclopentenones.The internal displacement reaction leading to the furan ring apparently encounters an unfavorable A1,3-interaction in the transition state when a substituent group is present at the 2-position of the dicarbonyl compound.This steric interaction is not present in the transition state leading to the cyclopentene ring.An efficient synthesis of cis-jasmone was carried out using this methodology.
- Padwa, Albert,Ishida, Masaru,Muller, Cheryl L.,Murphree, S. Shaun
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p. 1170 - 1178
(2007/10/02)
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- Hydroacylation of Alkyl Vinyl Ketones and Acrylic Esters Using Organotetracarbonylferrates. Synthesis of 1,4-Dicarbonyl Compounds
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Alkyl vinyl ketones and acrylic esters were hydroacylated with organotetracarbonylferrates to the corresponding 1,4-diketones and 4-oxo carboxylic acid derivatives in good yield in dipolar aprotic solvents such as N,N-dimethylacetamide.Addition of 18-crown-6 improved the yield. cis-Jasmone and γ-jasmolactone were synthesized by use of these reactions.
- Yamashita, Masakazu,Tashika, Haruyoshi,Uchida, Masaya
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p. 1257 - 1261
(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 facile synthesis of 1,4-diketones
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1,4-Diketones may conveniently be synthesized by the addition of 2-methylcyclopropenyllithium to N-methoxy-N-methylcarboxamides followed by hydrolysis of intermediate cyclopropyl ketone adducts on silica gel. The new method has been applied to the synthesis of cis-jasmone.
- Bergman,Nilsson,Wickberg
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p. 2783 - 2786
(2007/10/02)
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- NEW METHOD FOR SYNTHESIS OF cis-JASMONE
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A new method for the synthesis of cis-jasmone was developed on the basis of the regioselective and stereoselective alkylation of the enolic isobutyl ether of 1,3-cyclopentanedione.
- Lis, L. G.,Zheldakova, T. A.,Pap, A. A.,Lakhvich, F. A.
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p. 1452 - 1455
(2007/10/02)
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- A NEW ROUTE TO DISUBSTITUTED CYCLOPENTENONES USING 2,3-DIBROMO-1-(PHENYLSULFONYL)-1-PROPENE AS A PIVOTAL REAGENT
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2,3-Dibromo-1-(phenylsulfonyl)-1-propene acts as a dielectrophile towards 1,3-diketones and β-ketoesters providing an entry into a variety of 2,3-disubstituted cyclopentenones including cis-jasmone.
- Murphree, S. Shaun,Muller, Cheryl L.,Padwa, Albert
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p. 6145 - 6148
(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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- (Z)-7-NITRO-3-HEPTENE AS CENTRAL INTERMEDIATE FOR THE SYNTHESIS OF JASMONE, METHYL JASMONATE, AND γ-JASMONOLACTONE
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(Z)-7-Nitro-3-heptene is used as central intermediate in the synthesis of jasmone (13), methyl jasmonate (15), and γ-jasmonolactone (16), three jasmin constituents.Conjugate addition of the title compound, by heterogeneous catalysis, to methyl vinyl ketone, or acrolein, or methyl acrylate, followed by Nef reaction, affords (Z)-undec-8-ene-2,5-dione, (Z)-1,4-dioxo-dec-7-ene, and (Z)-4-oxo-dec-7-enoic acid methyl ester respectively, which are easily converted into jasmone, methyl jasmonate and γ-jasmonolactone.
- Ballini, Roberto,Petrini, Marino,Marotta, Emanuela
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p. 575 - 584
(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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- A NEW READY ROUTE TO 1,4-KETOALDEHYDES AND 1,4-DIKETONES WITH APPLICATION TO THE SYNTHESIS OF Z-JASMONE AND DIHYDROJASMONE
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A new three-step synthesis in good overall yield of 1,4-ketoaldehydes and 1,4-diketones is described.The method involves two sequential coupling reaction of reagents with S-phenyl carbonochloridothioate in the presence of nickel(II) or iron(III) complexes as catalysts.Application of this reaction to the synthesis of Z-jasmone and dihydrojasmone is also described.
- Fiandanese, V.,Marchese, G.,Naso, F.
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p. 3587 - 3590
(2007/10/02)
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- MICHAEL ADDITION OF NOVEL ACYL ANION EQUIVALENTS GENERATED BY THE ELECTROREDUCTION OF OXAZOLINIUM SALTS TO ACTIVATED OLEFINS
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Electroreduction of oxazolinium salts gave novel acyl anion equivalents (AAEs), and the Michael addition of these AAEs to activated olefins has been found to be promoted effectively by the addition of chlorotrimethylsilane into the reaction system.This reaction was applied to the synthesis of cis-jasmone and dihydrojasmone.
- Shono, Tatsuya,Kashimura, Shigenori,Yamaguchi, Yoshihide,Kuwata, Fumitaka
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p. 4411 - 4414
(2007/10/02)
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- A MILD AND STEREOSPECIFIC CONVERSION OF VICINAL DIOLS INTO OLEFINS VIA 2-METHOXY-1,3-DIOXOLANE DERIVATIVES
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An efficient and practical method for the stereospecific synthesis of olefins from vicinal diols via the corresponding 2-methoxy-1,3-dioxolanes is reported.
- Ando, Masayoshi,Ohhara, Hiroshi,Takase, Kahei
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p. 879 - 882
(2007/10/02)
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- A New, Short Synthesis of Z-Jasmone
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Z-Jasmone (1) was prepared from ethylene ketal of O,O-diethyl-4-oxo-pentanephosphonate (2) in four steps in 36percent overall yield.A key step in this synthesis is the oxygenation of the α-phosphonate carbanion generated from the monoalkylation product of 2 with Z-3-hexen-1-yl iodide (3). - Keywords: Z-Jasmone Synthesis, Ethylene Ketal, O,O-diethyl-4-oxo-pentanephosphonate, Z-3-Hexen-1-yl Iodide
- Mikolajczyk, Marian,Midura, Wanda
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p. 263 - 264
(2007/10/02)
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- JASMONOIDS: PART 1. DICARBANION ALKYLATION APPROACH TO SYNTHESIS OF Z-JASMONE/DIHYDROJASMONE
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Application of the dicarbanion alkylation strategy to 2-acetyl-4-methyl-butyrolactone 1 has resulted in a 4 step/5 step synthesis of dihydrojasmone 6a/z-jasmone 7 respectively.
- Reddy, R. Thimma,Nayak, U. R.
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p. 713 - 722
(2007/10/02)
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- NOVEL SYNTHESES OF JASMONE AND ALLYLRETHRONE
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Jasmone and Allylrethrone were obtained from cyclopentadiene in three steps.
- Liu, Zhu-Jin,Rong, Guo-Bin
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p. 871 - 876
(2007/10/02)
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- AN EFFICIENT ROUTE TO 2-(FORMYLMETHYL)-CYCLOPENTEN-3-ONE AND ITS 1-METHYL-CONGENER
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We describe a five-step synthesis of 2-(formylmethyl)-cyclopenten-3-one (1a) and its 1-methyl congener (1b) from 6-methylhept-5-ene-2-one by way of the respective 2-(3-methylbut-2-enyl)-cyclopenten-3-ones (5) and selective ozonolysis of these intermediates.
- Armstead, David A.,Mann, John
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p. 1147 - 1152
(2007/10/02)
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- NEW SYNTHETIC METHOD OF (Z)-4-ALKENOIC ACIDS USING RING-OPENING REACTION OF (Z)-4-HEXENOLIDE WITH ORGANOCOPPER REAGENT
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(Z)-4-Hexenolide reacted regioselectively with diorganocuprates to give (Z)-4-alkenoic acids in high yields.Synthetic utility was demonstrated by the convenient synthesis of cis-jasmone.
- Fujisawa, Tamotsu,Umezu, Kazuto,Kawashima, Masatoshi
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p. 1795 - 1798
(2007/10/02)
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- A NEW ROUTE TO 2,3-DIALKYLATED CYCLOPENTENONES. AN EFFICIENT SYNTHESIS OF cis-JASMONE
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An efficient synthesis of 2,3-dialkylated cyclopentenoids, starting from acyclic precursors, is reported.The synthetic approach has been applied to the preparation of cis-jasmone.
- Cainelli, Gianfranco,Panunzio, Mauro,Plessi, Laura,Martelli, Giorgio,Spunta, Giuseppe
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p. 327 - 330
(2007/10/02)
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- A Short Synthesis of Dihydrojasmone, cis- and trans-Jasmones
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The titled jasmones were synthesized from N,N'-dimethyl-2-oxo-1,3-propanedisulfoanilide, a new three carbon building block for organic preparation.
- Ogura, Fumio,Otsubo, Tetsuo,Sakamoto, Tetsuo,Yamaguchi, Hachiro
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p. 1691 - 1692
(2007/10/02)
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- A NEW ROUTE TO 1,4-DIKETONES AND ITS APPLICATION TO (Z)-JASMONE AND DIHYDROJASMONE SYNTHESIS.
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(Z)-Jasmone, dihydrojasmone and other 3-methylcyclopent-2-en-1-ones are easily synthetized starting from aldehydes and 1-(2-methyl-1,3-dioxolane-2-yl)-2-nitroethane as reagent for 3-ketobutyl anion synthon.Nitro-aldol condensation is the chainleghtening reaction followed by oxidation and denitration via p-toluenesulfonylhydrazones of the corresponding α-nitroketones.Removal of protecting groups gives 1,4-diketones which are then cyclized with alkali.
- Rosini, Goffredo,Ballini, Roberto,Sorrenti, Pietro
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p. 4127 - 4132
(2007/10/02)
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- CYCLOPENTENONES FROM 1,2-DISILOXYCYCLOBUTENE VIA SILYLATED 1-VINYLCYCLOPROPANOLS. APPLICATION TO THE SYNTHESIS OF DIHYDROJASMONE AND CIS-JASMONE
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An effective synthesis of 2,3-disubstituted 2-cyclopentenones involves C4 - C3 ring contraction of the readily available 1,2-disiloxycyclobutene followed by thermal C3 - C5 ring enlargement of trimethylsiloxyvinyl-cyclopropanes.To illustrate the convenience of this new approach the total syntheses of 2-methyl-3-p-tolyl-2-cyclopentenone, dihydrojasmone, and cis-jasmone are reported.
- Salauen, J.,Almirantis, Y.
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p. 2421 - 2428
(2007/10/02)
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- A Convenient Preparative Method of Jasmone and its Related Compounds
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The reaction of (Z)-hept-4-enoic acid (1) with vinylmagnesium bromide gave (Z)-undeca-1,8-dien-5-one (2).The oxidation of the terminal vinylic group of (2) affords (Z)-undec-8-ene-2,5-dione (3).Jasmone (4) was obtained by the usual alkali cyclization of (3).A variety of alkylcyclopentenones were prepared by the same method.
- Watanabe, Shoji,Fujita, Tsutomu,Suga, Kyoichi,Haibara, Michio
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p. 1739 - 1741
(2007/10/02)
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- Reaction of β-halo α,β-unsaturated ketons with cuprate reagents. Efficient syntheses of β,β-dialkyl ketones and β-alkyl α,β-unsaturated ketones. A synthesis of (Z)-jasmone
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Treatment of the 3-halo-2-cyclohexen-1-ones 11-15 and 17 with an excess of lithium dimethylcuprate provided good to excellent yields of the corresponding 3,3-dimethylcyclohexanones 21-24.Similar reactions involving the β-bromo cyclopentenones 19 and 20 stopped at the monoaddition stage, producing the cyclopentenones 40 and 43.Reaction of the β-bromo cyclohexenones 12 and 15 with 1.1 equiv. of lithium dimethylcuprate did not effect clean conversion of these substrates into the corresponding 3-methyl-2-cyclohexen-1-ones.When a series of β-bromo enones 12, 14-19were allowed to react with the lithium (phenylthio)(alkyl)cuprates 44-47, the correspondig β-alkyl enones were, in general, produced cleanly and efficiently.However, reaction of 3-bromo-2-methyl-2-cyclopenten-1-one (19) with the cuprate reagent 44 gave mainly the β-phenylthio enone 49.This undesired result could be avoided by employing, in the place of 19, The β-iodo cyclopentenone 50, which reacted smoothly with 44 to give a high yield of 2,3-dimethyl-2-cyclopenten-1-one (40).Reaction of 3-bromo-2-cyclohexen-1-one (14) with 3 equiv. of the mixed vinylcuprate reagent 48 gave 3-(3-butenyl)-2-cyclohexen-1-one (32).Alkylation of 1,3-cyclopentanedione with (Z)-1-chloro-2-pentene afforded compound 51, which was converted into the β-bromo enone 52.Treatment of the latter substance with lithium dimethylcuprate provided (Z)-jasmone (53).
- Piers, Edward,Cheng, Kin Fai,Nagakura, Isao
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p. 1256 - 1263
(2007/10/02)
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- Synthesis of cis-Jasmone via the Retroaldol-aldol Condensation of 3-(cis-3-hexenyl)-2-cyclopentenone in an Autoclave
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cis-Jasmone was efficiently synthesized from 2-cyclopentenone.The treatment of cyclopentenone with sodium p-toluenesulfinate gave 3-(p-tolylsulfonyl)cyclopentanone in a 92.5percent yield.The alkylation of the sulfone, after the protection of the ketone, with cis-1-bromo-3-hexene, followed by desulfonylation with 5percent hydrochloric acid in tetrahydrofuran, afforded 3-(cis-3-hexenyl)-2-cyclopentenone in a good yield.The retroaldol-aldol condensation of the cyclopentenone in a stainless steel autoclave in presence of 5percent sodium hydroxide yielded cis-jasmone in a 80percent yield.
- Yoshida, Takashi,Saito, Shojiro
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p. 3931 - 3932
(2007/10/02)
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- Jasmonoid Synthesis from cis-4-Heptenoic Acid
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Jesmonoids with cis-2-pentenyl side-chain such as cis-jasmone, methyl jasmonate, and jasmolone were easily synthesized from cis-4-heptenoic acid obtained by the ring opening reaction of β-propiolactone with di-cis-butenylcuprate.
- Sato, Toshio,Kawara, Tatsuo,Sakata, Kazumi,Fujisawa, Tamotsu
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p. 505 - 508
(2007/10/02)
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- 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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p. 1189 - 1192
(2007/10/02)
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- β-KETOLACTONE SYNTHONS. SHORT EFFICIENT SYNTHESES OF JASMONOIDS.
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The cyclopentanoid β-ketolactone 2, serving as the equivalent of a specific enolate of a 3-alkyl cyclopentanone, has been converted to several jasmonoid substances.
- Goldsmith, David J.,Thottathil, John K.
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p. 2447 - 2450
(2007/10/02)
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- SYNTHESE DE MONODIOXOLANNES DE DICETONES-1,4 ET DE DICETONES-1,4 AU MOYEN DES ANHYDRIDES MIXTES CARBOXYLIQUES ET CARBONIQUES: APPLICATION A LA PREPARATION DE LA DIHYDROJASMONE, DE LA Z-JASMONE ET DE LA DEHYDROJASMONE
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Levulinic acid 1 is easily converted by two steps into mixed carboxylic and carbonic anhydride 3 which reacts with the organolithium reagent issued from trimethylsilyl esters.Monoethylene acetal of 1,4-diketones 4 can be prepared; it is also possible to obtain 1,4-diketones 5 in one step by hot acid hydrolysis.The preparation of the dihydrojasmone 6d, Z-jasmone 6e and dehydrojasmone 6f shows the efficiency of the process.
- Moreau, J.-L.,Couffignal, R.,Arous-Chtara, R.
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p. 307 - 310
(2007/10/02)
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- New Routes to cis-Jasmone and Dihydrojasmone via 1,4-Diketones Exploiting the Mobile Activating Sulfonyl Group
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cis-Jasmone(1a) and dihydrojasmone(1b) are synthesized starting from cis-3-hexen-1-yl phenyl sulfone (6a) and n-hexyl phenyl sulfone (6b), respectively, through 1,4-diketones 3a,b.The key intermediates in these syntheses are the diketo sulfones 7a,b, which are prepared by two methods.The reaction of dilithiosulfones 12a,b with γ-valerolactone in tetrahydrofuran in the presence of hexamethylphosphoramide at -78 deg C gives the hydroxy keto sulfones 13a,b in satisfactory yields and the successive oxidation of these compounds with Jones reagent in acetone affords 7a,b in very good yields.On the other hand, the reaction of 12a,b with ethyl levulinate ethylene ketal gives the partially protected diketo sulfones 17a,b, from which 7a,b are obtained by removal of the protecting group.Cleavage of the carbon-sulfur bond in 7a,b, accomplished by aluminum amalgam in aqueous tetrahydrofuran, affords 3a,b which are then cyclized to 1a,b by heating over basic alumina in benzene.
- Mussatto, Maria Cristina,Savoia, Diego,Trombini, Claudio,Umani-Ronchi, Achille
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p. 4002 - 4005
(2007/10/02)
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- Synthesis of Dihydrojasmone and cis-Jasmone
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2-Ethoxycarbonyl-4-methoxycarbonyl-3-methyl-2-cyclopentenone (1), prepared readily from methyl acetoacetate, may be utilized for facile preparations of dihydro- and cis-jasmone.Compound 1 reacted with pentyl iodide and 1-bromo-2-pentyne in the presence of sodium hydride to give 2-ethoxycarbonyl-4-methoxycarbonyl-3-methyl-3-cyclopentenone (2) and 2-ethoxycarbonyl-4-methoxycarbonyl-3-methyl-2-(2-pentynyl)-3-cyclopentenone (3), respectively.Decarbalkoxylations of compound 2 and 3 afforded dihydrojasmone (4) and dehydrojasmone (5), respectively.Catalytic hydrogenation of dehydrojasmone (5) over a Pd-CaCO3 catalyst gave cis-jasmone (6).Keywords: methyl acetoacetate; ethyl γ-bromoacetoacetate; 2-cyclopentenone-2,4-dicarboxylate; dihydrojasmone; dehydrojasmone; cis-jasmone
- Kato, Tetsuzo,Kimura, Hitoshi,Masuko, Takashi,Shimosuka, Yasuhisa
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p. 349 - 351
(2007/10/02)
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- Abnormal Nazarov Reaction. A New Synthetic Approach to 2,3-Disubstituted 2-Cyclopentenones
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Acid-catalyzed reaction of β,β'-disubstituted cross conjugated dienones or the corresponding ethylene acetals gives mainly 2,3-disubstituted 2-cyclopentenones in stead of the simple Nazarov cyclization products, 3,4-disubstituted 2-cyclopentenones.This transformation is explained in terms of electrocyclic ring-closure, addition of hydroxylic solvent(s), tautomerization of the resulting 2-hydroxycyclopentanone intermediates, followed by solvolysis and isomerization.Based on this working hypothesis a new route to jasmonoids is disclosed which involves acid-treatment of the acyloin disilyl ethers derived from substituted glutarates.
- Hirano, Shigeo,Takagi, Seiji,Hiyama, Tamejiro,Nozaki, Hitosi
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p. 169 - 173
(2007/10/02)
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- Process for the preparation of cyclic ketones
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New process for the preparation of cyclic ketones possessing interesting organoleptic properties and including methyl 2-(cis-pent-2-enyl)-3-oxo-cyclopentylacetate and 3-methyl-2-(cis-pent-2-enyl)-cyclopent-2-enone, better known in the perfume industry as cis-methyl jasmonate and cis-jasmone respectively.
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