- Zinc(II) Catalysed Conjugate Addition of Grignard Reagents to α,β-Unsaturated Ketones
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Zinc(II)-diamine complexes are efficient catalysts for the conjugate additions of Grignard reagents to various α,β-unsaturated ketones.
- Jansen, Johan F. G. A.,Feringa, Ben L.
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- Highly enantioselective cyclization using cationic Rh(I) with chiral ligand
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Highly diastereoselective cyclization (> 99% de) of 3R (or S) 3,4-disubstituted 4-pentenals into the corresponding 3,4-cis(or trans)-disubstituted cyclopentanone and highly enantioselective cyclization (> 99% ee) of 4-substituted 4-pentenals into 3-substi
- Wu,Funakoshi,Sakai
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- LILY OF THE VALLEY ODORANT
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The present invention relates to the field of perfumery. More particularly, it relates to a compound of formula (I) as defined herein below, and its uses as perfuming ingredient, to control arthropods or as antimicrobial ingredient. Therefore, following what is mentioned herein, the present invention comprises the invention compound as part of a perfuming composition or of a perfumed consumer product. Moreover, the present invention relates to a properfume compound suitable to release the compound of formula (I).
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Page/Page column 31
(2021/10/22)
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- CuI-Catalysed Enantioselective Alkyl 1,4-Additions to (E)-Nitroalkenes and Cyclic Enones with Phosphino-Oxazoline Ligands
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Catalytic enantioselective conjugate additions of simple alkyl groups to nitroalkenes or cyclic enones that result in the formation of tertiary C–C bonds are described. For these stereoselective addition reactions, new chiral phosphino-oxazoline ligands w
- Shin, Minkyeong,Gu, Minji,Lim, Sung Soo,Kim, Min-Jae,Lee, JuHyung,Jin, HyeongGyu,Jang, Yun Hee,Jung, Byunghyuck
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p. 3122 - 3130
(2018/07/06)
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- Catalytic enantioselective conjugate addition of Grignard reagents to cyclic enones using C1-1,1′-bisisoquinoline-based chiral ligands
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New highly constrained chiral C1-1,1′-bisisoquinoline ligands were examined in the enantioselective conjugate addition of Grignard reagents to cyclohexenone and cyclopentenone. The desired 1,4-adducts were obtained in excellent yield and moderate enantiomeric excess (up to 35%). Copyright Taylor & Francis Group, LLC.
- Qi, Gao,Judeh, Zaher M.A.
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experimental part
p. 1585 - 1592
(2012/05/04)
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- Synthesis and AChE inhibitory activity of new chiral tetrahydroacridine analogues from terpenic cyclanones
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This work describes the enantioselective synthesis of a new series of terpenic chiral 9-aminotetrahydroacridine analogues. Several chiral ketones were synthesized from natural monoterpenes in an optically active form and subjected to the cyclodehydration reactions with anthranilonitrile in the presence of BF3·Et2O as catalyst. The 9-aminotetrahydroacridine analogues were tested as acetylcholinesterase (AChE) inhibitors. Based on qualitative structure-activity relationship some trends are suggested.
- Santos Pisoni, Diego dos,Sobieski da Costa, Jessé,Gamba, Douglas,Petzhold, Cesar Liberato,César de Amorim Borges, Antonio,Ceschi, Marco Antonio,Lunardi, Paula,Saraiva Gon?alves, Carlos Alberto
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experimental part
p. 526 - 535
(2010/04/06)
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- Chiral phosphinoazomethinylate salts as new 'one-step available' ligands for copper-catalyzed asymmetric conjugate addition
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Herein, we report the use of phosphinoazomethinylate salts as chiral efficient ligands for the copper-catalyzed asymmetric conjugate addition (ACA) of dialkylzinc to various enones. These tridentate P,N,O ligands are straightforwardly obtained in a one-step procedure from commercially available enantiopure α-aminoacids. Performing the conjugate addition in the greener AcOEt solvent, high enantioselectivities were reached for both cyclic and acyclic enones ranging between 72% to 98% ee and 96% to >99%, respectively. The 2/1 Cu/ligand ratio required to obtain high enantioselectivities, led us to envisage a copper-copper bi-metallic catalytic system for this transformation.
- Wencel, Joanna,Rix, Diane,Jennequin, Thomas,Labat, Stephane,Crevisy, Christophe,Mauduit, Marc
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p. 1804 - 1809
(2008/12/21)
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- Conjugate reduction of α,β-unsaturated carbonyl compounds catalyzed by a copper carbene complex
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(Matrix presented) An N-heterocyclic carbene copper chloride (NHC-CuCl) complex (2) has been prepared and used to catalyze the conjugate reduction of α,β-unsaturated carbonyl compounds. The combination of catalytic amounts of 2 and NaOt-Bu with poly(methy
- Jurkauskas, Valdas,Sadighi, Joseph P.,Buchwald, Stephen L.
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p. 2417 - 2420
(2007/10/03)
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- Access to optically pure 4- and 5-substituted lactones: A case of chemical-biocatalytical cooperation
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Optically pure or highly enantiomerically enriched 4- and 5-substituted lactones are rather difficult to obtain. Chemical or enzymatic syntheses alone are not particularly successful. A combination of chemical catalysis and biocatalysis, however, provides a convenient route to a variety of these useful chiral compounds. In this paper we describe the synthesis of several optically pure 4- and 5-substituted lactones obtained via whole cell-catalyzed Baeyer-Villiger oxidations of highly enantiomerically enriched 3-alkyl cyclic ketones. Such chiral ketones are readily accessed by recently developed copper-catalyzed asymmetric conjugate reductions of the corresponding enones. A very high proximal regioselectivity and complete chirality transfer was obtained by employing biological Baeyer-Villiger oxidations, using recombinant E. coli strains that overexpress cyclopentanone monooxygenase (CPMO). A comparative study showed that CPMO gives superior results to those obtained with cyclohexanone monooxygenase (CHMO) catalyzed oxidations.
- Wang, Shaozhao,Kayser, Margaret M.,Jurkauskas, Valdas
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p. 6222 - 6228
(2007/10/03)
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- Highly practical and enantioselective Cu-catalyzed conjugate addition of alkylzinc reagents to cyclic enones at ambient temperature
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(Matrix presented) A new ligand for Cu-catalyzed enantioselective additions of dialkylzincs to cyclic enones has been developed. In addition to providing good to excellent enantioselectivities with a range of cyclic enones and dialkylzincs, the ligand has several notworthy features: it can be readily prepared in just two steps, is an air-stable crystalline solid, and provides optimal performance at ambient temperature.
- Krauss, Isaac J.,Leighton, James L.
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p. 3201 - 3203
(2007/10/03)
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- A Radical Carbon-carbon Bind Forming Reaction: Indium Mediated Radical Addition to β-Substituted Conjugated Alkenes in Aqueous Media
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Indium-mediated 1,4-addition of alkyl radical to β-substituted conjugated alkenes in aqueous media has been developed. The reaction affords 1,4-addition products to various α,β-enones regiospecifically in high isolated yields.
- Jang, Doo Ok,Cho, Dae Hyan
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p. 631 - 633
(2007/10/03)
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- Chiral diselenide ligands for the asymmetric copper-catalyzed conjugate addition of Grignard reagents to enones
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The copper-catalyzed conjugate addition of Grignard reagents to enones in the presence of chiral diselenide oxazoline ligands has been studied and found to provide good yields and useful levels of asymmetric induction.
- Braga, Antonio L,Silva, Sandra J.N,Lüdtke, Diogo S,Drekener, Roberta L,Silveira, Claudio C,Rocha, Joao B.T,Wessjohann, Ludger A
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p. 7329 - 7331
(2007/10/03)
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- Asymmetric 1,4-reductions of and 1,4-additions to enoates and related systems
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One aspect of the present invention relates to methods for the transition-metal-catalyzed asymmetric 1,4-addition of a nucleophile, e.g., hydride, to cyclic and acyclic enoates and enones. In certain embodiments of the methods of the present invention, th
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- Highly Diastereoselective Intermolecular β-Addition of Alkyl Radicals to Chiral 2-(Arylsulfinyl)-2-cycloalkenones
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The diastereoselectivity of intermolecular β-addition of alkyl radicals to 2-(arylsulfinyl)-2-cycloalkenones depends largely upon the structure of the arylsulfinyl group. The reaction of 2-cyclopentenones or 2-cyclohexenones having a sterically bulky arylsulfinyl group such as (3,5-di-tert-butyl-4-methoxyphenyl)sulfinyl, (2,4,6-triisopropylphenyl)sulfinyl or (2,4,6-trimethylphenyl)sulfinyl group gives 3-alkyl-2-(arylsulfinyl)-1-cyclopentanones or 3-alkyl-2-(arylsulfinyl)-1-cyclohexanones in excellent yields and with high diastereoselectivity. Both the X-ray crystallographic analysis and the NOE experiment in the 1H NMR spectrum of (S)-2-[(2,4,6-triisopropylphenyl)sulfinyl]- and (S)-2-[(2,4,6-trimethylphenyl)sulfinyl]-2-cyclopentenone reveal an effective shielding of one of the olefin faces at the β-position by o-isopropyl and o-methyl groups. The addition of bidentate Lewis acids reverses the stereoselection through chelating the intermediates to give the addition products with high diastereoselectivity.
- Mase, Nobuyuki,Watanabe, Yoshihiko,Ueno, Yoshio,Toru, Takeshi
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p. 7794 - 7800
(2007/10/03)
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- Asymmetric catalytic intramolecular hydroacylation of 4-substituted pent-4-enals to β-substituted cyclopentanones
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The catalyst, [Rh(S,S-Me-duphos)(acetone)2]+, rapidly and efficiently converts 4-substituted pent-4-enals bearing primary and secondary substituents to the corresponding cyclopentanones and for a variety of substituents the ee was found to range from 93 to 96% at 25°C.
- Barnhart, Richard W.,McMorran, David A.,Bosnich
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p. 589 - 590
(2007/10/03)
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- Asymmetric catalysis. Asymmetric catalytic intramolecular hydroacylation of 4-pentenals using chiral rhodium diphosphine catalysts
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Catalysts of the type [Rh(chiral diphosphine)]+ convert 4-substituted 4-pentenals into the corresponding 3-substituted cyclopentanones with generally high turnover numbers and frequencies at 25 °C. The enantioselectivities of various substituted 4-pentenals with two chiral diphosphines have been explored. It was found that with the binap catalyst, almost complete enantioselectivity is observed for 4-pentenal substrates bearing 4-substituted tertiary substituents and for ester groups. Ketonic substituents give very high enantioselectivities. The mechanism of intramolecular hydroacylation has been explored, and it is suggested that an important consideration for obtaining high turnover frequencies is related to the acyl-alkyl reductive elimination mechanism which is inferred to occur by a process similar to ester hydrolysis. The origin of the enantioselection is discussed in terms of the interactions between the phenyl groups of the phosphine and the substituent of the pentenal.
- Barnhart, Richard W.,Wang, Xianqi,Noheda, Pedro,Bergens, Steven H.,Whelan, John,Bosnich
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p. 1821 - 1830
(2007/10/02)
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- ASYMMETRIC SYNTHESIS USING ENANTIOMERICALLY PURE 2-(p-ANISYLSULFINYL)-2-CYCLOALKENONES
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Conjugate additions of many organometallic reagents to 2-(p-anisylsulfinyl)-2-cycloalkenones, 2, proceed with much greater diastereoselectivity than additions to the corresponding 2-(p-tolylsulfinyl)-2-cycloalkenones, 7.Complexation of 2 with zinc dibromide followed by addition of various Grignard reagents lead, after reductive removal of the sulfoxide, to 3-substituted cycloalkanones of higher optical purity than those obtained from 7.Addition of methyltitanium triisopropoxide to 2-(p-anisylsulfinyl)-2-cyclohexenone, 2b, in the absence of zinc dibromide, proceeds with virtually complete asymmetric induction.
- Posner, Gary H.,Frye, Leah L.,Hulce, Martin
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p. 1401 - 1408
(2007/10/02)
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- ORGANOCOPPER CONJUGATE ADDITION REVISITED
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An efficient organocopper conjugate addition based on the use of equimolar amounts of an enone and an entering group is described.
- Suzuki, M.,Suzuki, T.,Kawagishi, T.,Noyori, R.
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p. 1247 - 1250
(2007/10/02)
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