The Experts below are selected from a list of 1860 Experts worldwide ranked by ideXlab platform
Yongmin Zhang - One of the best experts on this subject based on the ideXlab platform.
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Samarium Diiodide Mediated Coupling of Aroyl Chlorides
Chinese Journal of Chemistry, 2010Co-Authors: Zhi-farig U, Yongmin ZhangAbstract:α, α'-Stilbenediol dibenzoate compounds were synthesized in moderate to good yields through the coupling of aroyl chloride promoted by Samarium Diiodide under mild conditions.
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Synthesis of 1,3-diaryl-3-aminopropynes via the dethiolation of thioamides promoted by the Samarium/Samarium Diiodide mixed reagent
Journal of Chemical Research-s, 2005Co-Authors: Weixing Qian, Yongmin ZhangAbstract:Promoted by the Samarium/Samarium Diiodide mixed reagent, the C-H insertion of phenyl acetylene via the dethiolation of N,N-disubstituted aromatic thioamides was successfully performed to afford 1,3-diaryl-3-aminopropynesin good yields.
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A novel stereospecific aminocyclopropanation via the dethiolation of thioamides promoted by the Samarium/Samarium Diiodide mixed reagent
Journal of Chemical Research-s, 2005Co-Authors: Weixing Qian, Yongmin ZhangAbstract:The stereospecific aminocyclopropanation of styrene via the dethiolation of N,N-disubstituted aromatic thioamides promoted by the Samarium/Samarium Diiodide mixed reagent has been successfully performed.
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One‐Pot Syntheses of Amides from N‐Acylation of Nitroarenes with Esters Mediated by Samarium Diiodide
Synthetic Communications, 2004Co-Authors: Xiaoxia Wang, Hongyun Guo, Guanqun Xie, Yongmin ZhangAbstract:Abstract Mediated by Samarium Diiodide, various amides were prepared directly from nitroarenes and esters under mild conditions in a one‐pot procedure.
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Synthesis of trans-stilbenes utilising decarbonylation of α-chloro chloroformates mediated by Samarium Diiodide
Journal of Chemical Research, 2003Co-Authors: Yongmin ZhangAbstract:A new synthesis of trans-stilbenes has been achieved by decarbonylation of α-chloro chloroformates mediated by Samarium Diiodide in THF; this one pot reaction is completed within a few minutes at room temperature.
Hans-ulrich Reissig - One of the best experts on this subject based on the ideXlab platform.
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towards the core structure of strychnos alkaloids using Samarium Diiodide induced reactions of indole derivatives
Chemistry: A European Journal, 2013Co-Authors: Steffen Gross, Christine Beemelmanns, Hans-ulrich ReissigAbstract:This report describes the development of a first and second generation approach towards the synthesis of the ABCEG pentacyclic core structure of Strychnos alkaloids. First, we discuss a sequential approach applying a series of functional group transformations to prepare suitable precursors for cyclization reactions. These include attempts of Samarium Diiodide-induced cyclizations or a Barbier-type reaction of a transient lithium organyl, which successfully led to a tetracyclic key building block earlier used for the synthesis of strychnine. Secondly, we account our first steps towards the development of an atom-economical Samarium Diiodide-induced cascade reaction using “dimeric” indolyl ketones as cyclization precursors. In this context, we discuss plausible mechanisms for the Samarium Diiodide-induced cascade reaction as well as transformations of the obtained tetracyclic dihydroindoline derivatives.
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Samarium Diiodide induced ketyl het arene cyclisations towards novel n heterocycles
Chemical Society Reviews, 2011Co-Authors: Christine Beemelmanns, Hans-ulrich ReissigAbstract:In this tutorial review we discuss recent advances in the field of ketyl-(het)arene cyclisations promoted by Samarium Diiodide and related processes. Couplings of Samarium ketyls with carbon–carbon multiple bonds are perhaps the most useful reactions to create carbocycles and heterocycles of various ring sizes. They have also successfully been exploited for the synthesis of biologically active compounds or natural products. In this article we intend to summarise our diversity orientated approaches towards nitrogen heterocycles and emphasize other approaches with SmI2 as well as electrochemical cyclisation methods providing similar N-heterocycles. We also briefly discuss our recently published formal total synthesis of strychnine employing a new Samarium Diiodide induced cascade reaction as key step. All these examples demonstrate the high synthetic potential of Samarium ketyl-(het)arene cyclisations for the preparation of various types of important heterocyclic compounds.
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New Samarium Diiodide-induced cyclizations
Pure and Applied Chemistry, 2011Co-Authors: Christine Beemelmanns, Hans-ulrich ReissigAbstract:Samarium Diiodide (SmI 2 ) smoothly promotes the cyclizations of suitably substi- tuted carbonyl compounds with styrene subunits leading to benzannulated cyclooctenes. The intramolecular Samarium ketyl addition to arene or hetarene moieties enables a new, efficient, and highly stereoselective entry to dearomatized products such as hexahydronaphthalenes, steroid-like tetra- or pentacyclic compounds, or dihydroindole derivatives. The usefulness of the developed SmI 2 -induced cyclization method was demonstrated by the shortest formal total synthesis of the alkaloid strychnine.
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Medium-sized carbocycles by Samarium Diiodide-induced carbonyl-alkene cyclizations.
Organic letters, 2009Co-Authors: Jakub Saadi, Dieter Lentz, Hans-ulrich ReissigAbstract:Intramolecular Samarium Diiodide-induced carbonyl−alkene or carbonyl−alkyne coupling reactions afforded without high dilution conditions 9- and 10-membered benzannulated carbocycles of type II and III in surprisingly good yields and stereoselectivities. A novel Samarium Diiodide-mediated cascade process leading to tricyclic compounds of type IV was also observed. Bisbenzannulated 10- and 11-membered carbocycles were prepared in very good yields.
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Samarium Diiodide-induced couplings of carbonyl compounds with methoxyallene leading to 4-hydroxy 1-enol ethers.
Organic letters, 2003Co-Authors: Alexandra Hölemann, Hans-ulrich ReissigAbstract:A surprising Samarium Diiodide-induced coupling reaction of carbonyl compounds with methoxyallene provided 4-hydroxy 1-enol ethers, which are versatile synthetic building blocks. In this coupling reaction, methoxyallene serves as an acrolein equivalent, which cannot directly be employed.
Jimmin Fang - One of the best experts on this subject based on the ideXlab platform.
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The reactions of acylferrocenes with Samarium Diiodide: reduction, deoxygenation, reductive coupling and rearrangement
Journal of Organometallic Chemistry, 1999Co-Authors: Shean-jeng Jong, Jimmin Fang, Chun-hsu LinAbstract:Abstract Acylferrocenes reacted with Samarium Diiodide in the presence of water to give the corresponding (α-hydroxyalkyl)ferrocenes or alkylferrocenes depending on the reaction time and temperature. On treatment with Samarium Diiodide in the absence of water, ferrocenecarbaldehyde underwent a reductive coupling to give pinacols, whereas acetylferrocene yielded 3,3-diferrocenyl-2-butanone and 2,3-diferrocenyl-2-butene via the subsequent rearrangement and deoxygenation.
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Cooperative Catalysis of Samarium Diiodide and Mercaptan in a Stereoselective One-Pot Transformation of 5-Oxopentanals into δ-Lactones
Organic Letters, 1999Co-Authors: Jue-liang Hsu, And Chao-tsen Chen, Jimmin FangAbstract:We demonstrate a general method for conversion of various 5-oxopentanals to substituted δ-lactones and 1-oxa-2-decalones by the synergistic catalysis of Samarium Diiodide and 2-propanethiol (or dis...
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Coupling Reactions and Coupling−Alkylations of Thiophenecarbaldehydes Promoted by Samarium Diiodide
The Journal of Organic Chemistry, 1999Co-Authors: Shyh-ming Yang, Jimmin FangAbstract:The coupling reactions of 2-thiophenecarbaldehyde with aromatic or aliphatic aldehydes were promoted by Samarium Diiodide in the presence of hexamethylphosphoramide to give C-5 hydroxyalkylation products. The coupling reactions of 3-thiophenecarbaldehyde occurred at C-2, and the subsequent alkylations occurred at the sulfur atom, accompanied by a concurrent opening of the thiophene ring to afford γ-lactols. Double hydroxyalkylations of 2- and 3-thiophenecarbaldehydes were also carried out under appropriate reaction conditions. Synthetic applications of these thiophenecarbonyl coupling products were demonstrated, for example, by elaboration to furans, butenolides, and thiophene-fused polycyclic compounds.
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phenyl carbonyl coupling reactions promoted by Samarium Diiodide and hexamethylphosphoramide
Journal of Organic Chemistry, 1997Co-Authors: Jiannshyng Shiue, Jimmin FangAbstract:By mediation of Samarium Diiodide and hexamethylphosphoramide, benzaldehydes and acetophenones underwent self- and cross-couplings to give the products having linkages at the para-carbons of phenyl rings and the carbonyl groups. The phenyl−carbonyl coupling of 2,5-dimethoxybenzaldehyde generated a Sm(III)−enolate intermediate, which was trapped by alkyl halides in a stereospecific manner to give uncommon 1,4-dialkyl-2,5-cyclohexadiene-1-carboxaldehydes. The benzaldehydes bearing tethered carbonyl chains proceeded with intramolecular phenyl−carbonyl couplings to afford fused benzocycles.
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Phenyl−Carbonyl Coupling Reactions Promoted by Samarium Diiodide and Hexamethylphosphoramide
Journal of Organic Chemistry, 1997Co-Authors: Jiannshyng Shiue, Jimmin FangAbstract:By mediation of Samarium Diiodide and hexamethylphosphoramide, benzaldehydes and acetophenones underwent self- and cross-couplings to give the products having linkages at the para-carbons of phenyl rings and the carbonyl groups. The phenyl−carbonyl coupling of 2,5-dimethoxybenzaldehyde generated a Sm(III)−enolate intermediate, which was trapped by alkyl halides in a stereospecific manner to give uncommon 1,4-dialkyl-2,5-cyclohexadiene-1-carboxaldehydes. The benzaldehydes bearing tethered carbonyl chains proceeded with intramolecular phenyl−carbonyl couplings to afford fused benzocycles.
Tadahiro Kudo - One of the best experts on this subject based on the ideXlab platform.
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Facile deoxygenation of dicarbonyl compounds using a Samarium Diiodide-additive system.
Chemical & pharmaceutical bulletin, 2005Co-Authors: Yasuko Kamochi, Tadahiro Kudo, Toshinobu Masuda, Akira TakadateAbstract:The reduction of α- and β-dicarbonyl compounds was investigated with Samarium Diiodide in the presence of additive. Diketones and ketocarboxylic acids were easily reduced at room temperature to give the mono-alcohols in good to excellent yield, and ketoester afforded the saturated ester as the major product in moderate yield. These reductions containing the reductive deoxygenation can be rapidly performed under the facile and mild conditions by this method.
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Rapid reduction of a variety of organic functionalities including a new selective reduction with Samarium Diiodide
Yakugaku zasshi : Journal of the Pharmaceutical Society of Japan, 2000Co-Authors: Yasuko Kamochi, Tadahiro KudoAbstract:This review deals with the rapid reduction of a variety of organic functionalities, including a new selective reduction of carboxylic acid, with Samarium Diiodide in the presence of additives under mild conditions. The single electron donor ability of Samarium Diiodide can be enhanced with ligands around Sm2+ when sufficient electrons are supplied from the ligands. Mechanistic consideration of this enhancement led to our finding that carboxylic acid, ester, amide, nitrile, pyridine and other functionalities were rapidly reduced with Samarium Diiodide in the presence of a base, acid, water and methanol as ligands at room temperature in good yields. Particularly, these systems directly reduced carboxylic acid into alcohol and a Samarium Diiodide--85% phosphoric acid system immediately reduced an aromatic primary amide to aldehyde in good yield. Pyridines were reduced to piperidines with a Samarium Diiodide-base or water system in excellent yields; also, the aromatic nucleus of phenol derivatives was rapidly reduced with a Samarium Diiodide-base system. Furthermore, these organic functionalities were rapidly reduced with an Sm or Yb metal-hydrochloric acid system. Aliphatic and aromatic carboxylic acids with a coexisting aldehyde or that bearing a formyl group were selectively reduced to the corresponding alcohols with a new Samarium Diiodide-Samarium triflate-methanol-base or water system within a few minutes at room temperature in good to almost quantitative yield.
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Novel and facile reduction of phenol derivatives with Samarium Diiodide-base system
Tetrahedron Letters, 1994Co-Authors: Yasuko Kamochi, Tadahiro KudoAbstract:Abstract Phenol was rapidly reduced with Samarium Diiodide-base system in the presence of protic solvent at room temperature to afford 3-cyclohexen-1-ol accompanied by cyclohexanol. The similar reduction of 4-methoxyphenol and 2-naphthol gave 4-hydroxycyclohexanone and 1,2,3,4-tetrahydro-2-naphthol in excellent yield, respectively.
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The novel reduction of pyridine derivatives with Samarium Diiodide
HETEROCYCLES, 1993Co-Authors: Yasuko Kamochi, Tadahiro KudoAbstract:Pyridine was rapidly reduced into piperidine with Samarium Diiodide in the presence of water at room temperature in excellent yield. On the similar reactions of pyridine derivatives bearing chloro, amino and cyano functionalities with Samarium Diiodide−H 2 O−THF system, these functionalities were partly eliminated with this system to afford pyridine or piperidine. Furthermore, pyridinecarboxamides were reduced with this system to give the corresponding methylpyridines and 2-pyridinecarboxylic acid was reduced to give 2-methylpyridine as the major products
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Reductions of carboxylic acids and their derivatives using Samarium Diiodide-acid system
Tetrahedron, 1992Co-Authors: Yasuko Kamochi, Tadahiro KudoAbstract:Abstract Carboxylic acid was converted to alcohol in a facile-rapid reduction using Samarium Diiodide in protic solvent under a basic or acidic medium at room temperature in high yield. A similar reaction of ester and anhydride reduced to the corresponding alcohol as the major products and nitrile afforded amine. Amide was rapidly reduced under a basic medium to afford alcohol, but the reduction with Samarium Diiodide-acid system of amide gave aldehyde in quantitative yield.
Jean-louis Namy - One of the best experts on this subject based on the ideXlab platform.
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Samarium Diiodide promoted reactions of a diphenyl α-iminoketone, a new synthesis of some pyrrole derivatives
Tetrahedron, 2001Co-Authors: Sorin Farcas, Jean-louis NamyAbstract:Abstract The reduction of a diphenyl α-iminoketone with Samarium Diiodide has been studied. A fast two-electron transfer gives a Samarium (Z)-enamidolate, which is protonated to afford an α-aminoketone or reacted with a variety of ketones to furnish pyrrole derivatives. Possible mechanisms are proposed.
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Samarium Diiodide nickel Diiodide an efficient system for homo and heterocoupling reactions of imines
Tetrahedron Letters, 1999Co-Authors: Fouzia Machrouhi, Jean-louis NamyAbstract:Abstract Samarium Diiodide in the presence of a catalytic amount of nickel Diiodide mediates a very fast dimerization of imines into vicinal diamines and the mixed coupling of imines and ketones to give β-amino alcohols.
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Samarium Diiodide/NICKEL Diiodide AN EFFICIENT SYSTEM FOR HOMO AND HETEROCOUPLING REACTIONS OF IMINES
Tetrahedron Letters, 1999Co-Authors: Fouzia Machrouhi, Jean-louis NamyAbstract:Abstract Samarium Diiodide in the presence of a catalytic amount of nickel Diiodide mediates a very fast dimerization of imines into vicinal diamines and the mixed coupling of imines and ketones to give β-amino alcohols.
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Nucleophilic acylation of esters by acid chlorides mediated by Samarium Diiodide: Formation and use of Samarium enediolates
Tetrahedron Letters, 1997Co-Authors: Fouzia Machrouhi, Jean-louis Namy, Henri B. KaganAbstract:Abstract Acid chlorides react with esters in the presence of Samarium Diiodide and catalytic amounts of NiI 2 to afford Samarium enediolates which can further react with electrophiles such as water or aldehydes to give respectively α-ketols or α-dihydroxyketones.
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Preparation and reactions of Samarium Diiodide in nitriles
Tetrahedron, 1996Co-Authors: Béatrice Hamann, Jean-louis Namy, Henri B. KaganAbstract:Abstract Samarium Diiodide can be prepared from Samarium metal in various nitriles. Because of its chemical inertness pivalonitrile is the most suitable solvent. Organic reactions mediated by SmI 2 are slower than in THF, but selectivities are often improved. Reactions are greatly accelerated by addition of catalytic amounts of some transition metal salts.
