- Copper/palladium-catalyzed 1,4 reduction and asymmetric allylic alkylation of α,β-unsaturated ketones: Enantioselective dual catalysis
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Cooperative efforts: The catalytic coupling of the two organometallic intermediates is possible through a Cu/Pd-based dual catalysis (see scheme; LG=leaving group), in which the CuI catalytic cycle generates catalytically the starting material
- Nahra, Fady,Mace, Yohan,Lambin, Dominique,Riant, Olivier
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Read Online
- Cycloalkenone Synthesis via Lewis Acid Catalyzed Retro Diels-Alder Reactions of Norbornene Derivatives: Synthesis of 12-Oxophytodienoic Acid
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Norbornene derivatives of type 1 undergo retro Diels-Alder reactions at or below ambient temperature in the presence of methylaluminium dichloride and a reactive dienophile.Application of the cycloreversion methodology to the synthesis of 12-oxophyt
- Grieco, Paul A.,Abood, Norman
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Read Online
- Hydroxy chalcogenide-promoted Morita-Baylis-Hillman Alkylation reaction: Intermolecular applications with alkyl halides as electrophiles
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Hydroxysulfides acted as catalysts to promote the Morita-Baylis-Hillman alkylation reaction of cyclohexenones and dihydropyridinones. The procedure worked efficiently with a variety of halides as electrophiles. Side reactions were in competition with the MBH alkylation, but fine-tuning the reaction conditions minimized their occurence.
- Gradillas, Ana,Belmonte, Efres,Da Silva, Rondes Ferreira,Perez-Castells, Javier
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p. 1935 - 1941
(2014/04/03)
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- Hydroxy Chalcogenide-Promoted Morita-Baylis-Hillman Alkylation Reaction: Intermolecular Applications with Alkyl Halides as Electrophiles
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Hydroxysulfides acted as catalysts to promote the Morita-Baylis-Hillman alkylation reaction of cyclohexenones and dihydropyridinones. The procedure worked efficiently with a variety of halides as electrophiles. Side reactions were in competition with the
- Gradillas, Ana,Belmonte, Efres,Da Silva, Rondes Ferreira,Prez-Castells, Javier
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p. 1935 - 1941
(2015/10/05)
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- Versatile CuI/Pd0 dual catalysis for the synthesis of quaternary α-allylated carbonyl compounds: Development, mechanistic investigations and scope
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We report herein a versatile cooperative dual catalysis reaction based on a CuI/Pd0 system. Mechanistic investigation shows that every component plays a crucial role in determining the reaction outcome. The reaction is successfully extended to various substrates; such as α,β-unsaturated ketones, malonates and coumarins. The strategy tolerates different substitution patterns and affords good yields for each family of substrates.
- Nahra, Fady,Mace, Yohan,Boreux, Arnaud,Billard, Francois,Riant, Olivier
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p. 10970 - 10981
(2014/09/17)
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- From vinyl pyranoses to carbasugars by an iron-catalyzed reaction complementary to classical Ferrier carbocyclization
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Starting from vinyl pyranoses an iron-catalyzed tandem isomerization- intramolecular aldolization reaction was developed to prepare cyclohexenone derivatives bearing substituents on the double bond, and it has been applied in a short synthesis of 4-epi-ga
- Mac, Dinh Hung,Samineni, Ramesh,Petrignet, Julien,Srihari, Pabbaraja,Chandrasekhar, Srivari,Yadav, Jhillu Singh,Gree, Rene
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supporting information; experimental part
p. 4717 - 4719
(2010/01/16)
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- Lithium naphthalenide induced reductive selenenylation of α-cyano ketones: A regiocontrolled process for α-phenylseleno ketones and one-pot conversion into enone system
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An efficient procedure for the regiocontrolled synthesis of α-phenylseleno ketones has been developed, making use of the lithium naphthalenide induced reductive selenenylation of the α-cyano ketone system as a key operation. Moreover, seleno ketones thus generated in situ, upon subsequent treatment with hydrogen peroxide and acetic acid, could be further converted into the corresponding enones with a high degree of regioselectivity, presumably due to the lithium salt mediated selenoxide syn-elimination process. Georg Thieme Verlag Stuttgart.
- Zhu, Jia-Liang,Ko, Yen-Chun,Kuo, Chun-Wei,Shia, Kak-Shan
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p. 1274 - 1278
(2008/01/08)
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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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- A Novel Palladium-Catalyzed Intramolecular Redox Reaction
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matrix presented A new type of palladium-catalyzed redox reaction is described, forming enones from 2-(2-bromobenzyl)-ketones with an overall loss of HBr. The scope and limitations of the reaction are demonstrated by a series of cyclic and acyclic substra
- Hoegenauer, Klemens,Mulzer, Johann
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p. 1495 - 1497
(2007/10/03)
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- Strictly regiocontrolled α-monosubstitution of cyclic carbonyl compounds with alkynyl and alkyl groups via Pd-catalyzed coupling of cyclic α-iodoenones with organozincs
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The conditions for the Pd-catalyzed cross coupling of cyclic α-iodoenones, such as 2-iodo-2-cyclohexenone, with alkynylzincs have been optimized. The use of tris(o-furyl)phosphine (TFP) as a ligand and DMF as a solvent has led to the formation of α-alkynylenones in excellent yields. This optimized procedure has been applied to the synthesis of (±)-harveynone and (±)-tricholomenyn A in high yields. Investigation of related α-alkylation reactions using alkylzincs has revealed the following. Methylzinc and primary alkylzinc derivatives readily undergo Pd-catalyzed cross coupling with α-iodoenones. Although (s-Bu)2Zn also undergoes Pd-catalyzed cross coupling, only the n-Bu-substituted products were obtained, α-Benzylation and α-homobenzylation can proceed satisfactorily, whereas allylzinc and propargylzinc derivatives undergo only addition to the carbonyl group. Although some promising results have been obtained in α-homoallylation and α-homopropargylation, these reactions need to be further improved. (C) 2000 Elsevier Science Ltd.
- Negishi, Ei-Ichi,Tan, Ze,Liou, Show-Yee,Liao, Baiqiao
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p. 10197 - 10207
(2007/10/03)
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- Applications of the β-azidonation reaction to organic synthesis. α,β- Enones, conjugate addition, and γ-lactam annulation
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The β-azido functionalization reaction provides a mechanistically different enone synthesis that involves treatment of 2 with fluoride anion to effect desilylation and concomitant β-elimination to give 3. Table 1 lists a number of examples of the direct conversion of a TIPS enol ether into the corresponding α,β-enone via a β-azido TIPS enol ether. The β-azido group can be ionized with Me3Al or Me2AlCl and the intermediate enonium ion trapped by a variety of nucleophiles such as an allylstannane, electron-rich aromatics, TMS enol ethers, Et2AlCN, Me2AlCCR, Me4AlLi, and vinylaluminum reagents to give the products listed in Table 2. The diastereoselectivity of the reaction of a 4-substituted enonium ion with indole shows an unusual increase of selectivity with increasing temperature. Reduction of the azide 2 provides access to β-amino TIPS enol ethers 5, which, for example, can be converted into a cinnamide derivative and cyclized via a putative 'ene' process into a γ-lactam.
- Magnus, Philip
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p. 12486 - 12499
(2007/10/03)
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- Regioselective Preparation of α,β-Unsaturated Ketones via the Direct Dehydrogenation of Triisopropylsilyl Enol Ethers
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Treatment of the triisopropyl enol ethers 1a-h with ceric ammonium nitrate in dimethylformamide at 0 deg C afforded the α,β-unsaturated ketones 2a-h in 63-98percent yield.
- Evans, P. Andrew,Longmire, James M.,Modi, Dilip P.
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p. 3985 - 3988
(2007/10/02)
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- A General Synthesis of 2-Substituted Cyclohex-2-enones
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A new synthesis of 2-substituted cyclohex-2-enones has been achieved using a sequence involving the aldol reaction of the aluminium enolate derived from thiolate addition to cyclohex-2-enone, followed by dehydration, rearrangement and desulfurisation.
- Armitage, Mark A.,Lathbury, David C.,Mitchell, Michael B.
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p. 1551 - 1552
(2007/10/02)
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- SYNTHESES DE CYCLOHEXENONES α-SUBSTITUEES VIA LA THERMOLYSE DE CETOSULFOXYDES TERTIAIRES
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The sulfenylation-dehydrosulfenylation method, combined with carbon-carbon bond forming reactions, has been applied to the synthesis of some α-functionalized cyclohexenones 3.Hence, the sodium anion of the 2-methylthiocyclohexanone in THF reacts with primary, allyl and benzyl halides as well as with Michael acceptors to lead to the tertiary ketosulfides 1a-j.Further oxidation by NaIO4 and thermolysis in boiling toluene of the resulting sulfoxides 2 have been performed.The scope and limitations of this strategy are also discussed. Key Words: α-functionalized cyclohexenones; tertiary ketosulfides and ketosulfoxides; sulfenylation and deshydrosulfenylation; thermolysis.
- Barillier, Daniel,Benhida, Rachid,Vazeux, Michel
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- A Novel Vinyl Anion Equivalent. An Extremely Short Synthesis of 2-Substituted 2-Cycloalkenones and Prostaglandin Key Intermediates via Destannylselenenylation
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The preparation of a novel vinyl anion equivalent and a new destannylselenenylation procedure are described.The conjugate addition of (tributylstannyl)lithium to 2-(phenylseleno)-2-cycloalkenones, followed by the trapping of the resulting enolates with al
- Kusuda, Shinya,Watanabe, Yoshihiko,Ueno, Yoshio,Toru, Takeshi
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p. 3145 - 3152
(2007/10/02)
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- New Trialkylsilyl Enol Ether Chemistry: New Regiospecific Methodology for the Synthesis of α,β-Unsaturated Cyclic Ketones
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Treatment of TIPS enol ethers with PhIO/TMSN3 followed by desilylation/elimination with fluoride ion gives good yields of the α,β-unsaturated ketone.
- Magnus, Philip,Evans, Andrew,Lacour, Jerome
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p. 2933 - 2936
(2007/10/02)
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- PHOTOCLEAVAGE OF CARBON-TIN BOND ACTIVATED BY NEIGHBORING
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β-Stannyl ketones underwent various types of reaction upon UV-irradiation, depending upon the substitution pattern of the substrate, and upon the solvent used.
- Sato, Tadashi,Takezoe, Kohji
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p. 4003 - 4006
(2007/10/02)
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- 2-CYANO-6-METHOXYTETRAHYDROPYRAN, A USEFUL PROTECTED CYANOHYDRIN FOR 2-SUBSTITUTED CYCLOHEXENONE SYNTHESIS
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The title compound 1, easily prepared from commercially available glutaraldehyde, is a protected cyanohydrin useful as synthon for the preparation of 2-substituted cyclohexenones.
- Laredo, Georgina Cecilia,Maldonado, Luis Angel
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p. 179 - 182
(2007/10/02)
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- 2,3a,5,6,7,7a-HEXAHYDRO-3H,4H-BENZOTHIOPHENE-3,4-DIONE AND CYCLOPENTA-TETRAHYDROTHIOPHENE-3,4-DIONE ENOLATE ANIONS AS SYNTHETIC EQUIVALENTS TO CYCLOHEX-2-ENONE AND CYCLOPENT-2-ENONE C-2-CARBANIONS.
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An efficient procedure for α-alkylation of cyclohex-2-enone and cyclopent-2-enone involving a base-promoted tandem of retrograde Dieckmann-Michael reactions of the C-alkylated derivatives of the title heterocycles is presented.
- Baraldi, Pier Giovanni,Barco, Achille,Benetti, Simonetta,Pollini, Gian Piero,Zanirato, Vinicio
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p. 4291 - 4294
(2007/10/02)
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