- Secondary amides as hydrogen atom transfer promoters for reactions of samarium diiodide
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Two secondary amides (N-methylacetamide and 2-pyrrolidinone) were used as additives with SmI2 in THF to estimate the extent of N-H bond weakening upon coordination. Mechanistic and synthetic studies demonstrate significant bond-weakening, providing a reagent system capable of reducing a range of substrates through formal hydrogen atom transfer.
- Chciuk, Tesia V.,Li, Anna M.,Vazquez-Lopez, Andres,Anderson, William R.,Flowers, Robert A.
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supporting information
p. 290 - 293
(2017/11/27)
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- Carbonylation of organic halides with carbon monoxide mediated by samarium diiodide. Improvement and mechanistic investigations
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Under an atmospheric pressure of carbon monoxide, photoinduced reductive carbonylation of organic halides (RX) with samarium diiodide (SmI2) occurs to afford the corresponding unsymmetrical ketones (RC(O)CH2R) in good yields. Mechanistic insight into this carbonylation, especially the pathway for the generation of an acylsamarium species (RC(O)SmI2) as a key intermediate, is also investigated in detail.
- Tomisaka, Yuri,Harato, Nami,Sato, Masahiro,Nomoto, Akihiro,Ogawa, Akiya
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p. 1444 - 1446
(2007/10/03)
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- Samarium/N-bromosuccinimide-induced reductive dimerization of carbonyl compounds
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Stereoselective reductive coupling of carbonyl compounds has been achieved using samarium/N-bromosuccinimide in methanol. The combination of these agents has proved a powerful addition to the arsenal of samarium-based reductants currently utilized.
- Banik, Bimal K.,Banik, Indrani,Samajdar, Susanta,Cuellar, Rogelio
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p. 2319 - 2322
(2007/10/03)
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- Influence of HMPA on reducing power and reactivity of SmBr2
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(matrix presented) Addition of HMPA to SmBr2 in THF produces a reactant with an estimated redox potential of -2.63 ± 0.01 V (vs Ag/AgNO3). This powerful reductant is capable of reducing ketimines and alkyl chlorides at room temperature. Although the structure of the reductant has not been established, it is nonetheless a powerful addition to the arsenal of samarium-based reductants currently utilized.
- Knettle, Brian W.,Flowers II, Robert A.
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p. 2321 - 2324
(2007/10/03)
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- Direct Preparation of Lanthanoid Ester Homoenolates from 3-Halo Esters and Lanthanoid Metals: Their Homo-Reformatsky-Type Reaction with Carbonyl Compounds
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The direct reaction of ethyl 3-bromopropionate (2a) or 3-iodopropionate (2b) with lanthanoid metals (La, Ce, Nd, Sm) in tetrahydrofuran produces lanthanoid ester homoenolates (3), which react with ketones to give γ-lactones in good yields under mild conditions.The isolation of 3-phenylseleno (8a), 3-phenyltelluro (8b), and 3-tri-n-butylstannyl esters (10) from the reaction with diphenyl diselenide (7a), ditelluride (7b), and tri-n-butyltin iodide (9), respectively, suggests the formation of the lanthanoid ester homoenolate.
- Fukuzawa, Shin-ichi,Sumimoto, Norifumi,Fujinami, Tatsuo,Sakai, Shizuyoshi
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p. 1628 - 1631
(2007/10/02)
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- ORGANOCERIUM REAGENTS FROM IODINE ACTIVATED CERIUM METAL AND ORGANIC IODIDES: THEIR REACTIONS WITH CARBONYL COMPOUNDS
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Cerium metal activated by a trace of iodine reacted smoothly with alkyl, allyl, and aryl iodides to give the corresponding organocerium reagents.The reaction of the organocerium reagents thus prepared in situ with carbonyl compounds gave not only Grignard-type adducts but also reduction and reductive coupling products.
- Fukuzawa, Shin-ichi,Fujinami, Tatsuo,Sakai, Shizuyoshi
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p. 179 - 186
(2007/10/02)
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- A Facile and Direct Synthesis of γ-Lactones from Methyl β-Bromopropionate and Ketones mediated by Lanthanoid Metals
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ψ-Lactones were easily prepared from the direct reaction of methyl β-bromopropionate with ketones mediated by lanthanoid metals; a lanthanoid metal ester homoenolate (β-lanthanoid metal substituted ester) is postulated as a reaction intermediate.
- Fukuzawa, Shin-ichi,Fujinami, Tatsuo,Sakai, Shizuyoshi
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p. 475 - 476
(2007/10/02)
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- Divalent Lanthanide Derivatives in Organic Synthesis. 1. Mild Preparation of SmI2 and YbI2 and Their Use as Reducing or Coupling Agents
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The facile synthesis of SmI2 and YbI2 from corresponding metals in THF is described.The reactivity of these potentially powerful reducing agents toward a variety functional groups is tested.Epoxides and sulfoxides are deoxygenated.Aldehydes are selectively reduced in presence of ketones.Alkyl halides or tosylates are converted into alkanes.Only coupling products are obtained from benzylic or allylic halides.In the presence of a SmI2-THF solution, tertiary alcohols are easily obtained from reactions between ketones and alkyl halides.In a similar manner, SmI2 promotes straightforward alkylation of ketones by alkyl sulfonates.Selective addition of polyfunctional halides or tosylates to ketones may be performed.In these reactions, catalytic amounts of FeCl3 enhance the reactivity.
- Girard, P.,Namy, J. L.,Kagan, H. B.
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p. 2693 - 2698
(2007/10/02)
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