- Iron-Catalyzed Regiodivergent Hydrostannation of Alkynes: Intermediacy of Fe(IV)-H versus Fe(II)-Vinylidene
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We report an iron system, Cp*Fe(1,2-R2PC6H4X), which controls the Markovnikov and anti-Markovnikov hydrostannation of alkynes by tuning the ionic metal-heteroatom bonds (Fe-X) reactivity. The sequential addition of nBu3SnH to the iron-amido catalyst (1, X = HN-, R = Ph) affords a distannyl Fe(IV)-H species responsible for syn-addition of the Sn-H bond across the CC bond to produce branched α-vinylstannanes. Activation of the C(sp)-H bond of alkynes by an iron-aryloxide catalyst (2, X = O-, R = Cy) affords an iron(II) vinylidene intermediate, allowing for gem-addition of the Sn-H to the terminal-carbon producing β-vinylstannanes. These catalytic reactions exhibit excellent regioselectivity and broad functional group compatibility and enable the large-scale synthesis of diverse vinylstannanes. Many new reactions have been established based on such a synthetic Fe-X platform to demonstrate that the initial step of the catalysis is conveniently controlled by the activation of either the tin hydride or the alkyne substrate.
- Liu, Jianguo,Song, Heng,Wang, Tianlin,Jia, Jiong,Tong, Qing-Xiao,Tung, Chen-Ho,Wang, Wenguang
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supporting information
p. 409 - 419
(2021/01/12)
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- Stereostructure Clarifying Total Synthesis of the (Polyenoyl)tetramic Acid Militarinone B. A Highly Acid-Labile N-Protecting Group for Amides ?
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The 5S, 8′R, and 10′R configurations of militarinone B (3), which is a natural product from Paecilomyces militaris, should equal those in its biosynthetic precursor, militarinone C. The configuration at C-1′ emerged from syntheses of the militarinone B candidates 1′′S- and 1′′R-(5S,8′R,10′R)-3 from the building blocks 9, 11, 14, and 15a while introducing TMB as a more acid-labile N-protecting group for β-ketoamides than DMB. Comparisons of 1′′S- and 1′′R-(5S,8′R,10′R)-3 with natural militarinone B (3; reisolated from Nature) revealed identity versus distinctness.
- Drescher, Christian,Brückner, Reinhard
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p. 6194 - 6199
(2021/08/18)
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- Illuminating Stannylation
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We have developed photoboosted stannylation reactions of terminal alkynes (linear-selective hydrostannylation) and fluoroarenes (defluorostannylation), in which the stannyl anion is photoexcited to an excited triplet (T1) stannyl diradical species. This u
- Sakamoto, Kyoka,Nagashima, Yuki,Wang, Chao,Miyamoto, Kazunori,Tanaka, Ken,Uchiyama, Masanobu
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supporting information
p. 5629 - 5635
(2021/05/04)
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- Magnesium-Catalyzed Stereoselective Hydrostannylation of Internal and Terminal Alkynes
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A regio- and stereoselective magnesium-catalyzed hydrostannylation of internal and terminal alkynes has been developed. Excellent yields and selectivities are obtained for a wide range of terminal and internal symmetrical and unsymmetrical alkynes by usin
- Magre, Marc,Szewczyk, Marcin,Rueping, Magnus
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supporting information
p. 1594 - 1598
(2020/02/22)
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- Synthesis of (Z)-alkene-containing linear conjugated dienyl homoallylic alcohols by a palladium-catalyzed three-component reaction
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A synthesis of (Z)-alkene-containing linear conjugated dienyl homoallylic alcohols by using a palladium-catalyzed three-component reaction has been developed. This method shows good functional-group compatibility and generality, with high diastereoselectivity. Additionally, in many cases, the present method controls the alkene stereochemistry of the newly formed C-C bond and overcomes the inherent preference for (E)-alkene formation, giving (Z, E)- and (Z, Z)-products.
- Horino, Yoshikazu,Sakamoto, Juri,Murakami, Miki,Sugata, Miki
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supporting information
p. 1323 - 1327
(2020/08/21)
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- A Drastic Effect of TEMPO in Zinc-Catalyzed Stannylation of Terminal Alkynes with Hydrostannanes via Dehydrogenation and Oxidative Dehydrogenation
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With a system consisting of a catalytic zinc Lewis acid, pyridine, and TEMPO in a nitrile medium, terminal alkynes coupled with HSnBu3, providing alkynylstannanes with structural diversity. The resulting alkynylstannane, without being isolated, could be directly used for Pd- and Cu-catalyzed transformations to deliver internal alkynes and more intricate tin-atom-containing molecules. Mechanistic studies indicated that TEMPOSnBu3 formed in situ from TEMPO and HSnBu3 works to stannylate the terminal alkyne in collaboration with the zinc catalyst, and that both of dehydrogenation and oxidative dehydrogenation processes are uniquely involved in a single reaction. (Figure presented.).
- Kai, Yuichi,Oku, Shinya,Sakurai, Kyoko,Tani, Tomohiro,Tsuchimoto, Teruhisa
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- Z-Selective Hydrostannylation of Terminal and Internal C-C Triple Bonds Initiated by the Trityl Cation
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A metal-free method for the anti-addition of n-Bu3SnH across terminal and internal alkynes, including related α,β-unsaturated carboxyl compounds, is reported. The reaction is initiated by the trityl salt [Ph3C]+[B(C6F5)4]- and proceeds through β-tin-stabilized vinyl cations. Their reduction by hydride transfer from n-Bu3SnH explains the high Z-selectivity in the formation of the vinyl stannanes.
- Forster, Francis,Rendón López, Victoria M.,Oestreich, Martin
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supporting information
p. 2656 - 2659
(2018/09/10)
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- Ynamide Carbopalladation: A Flexible Route to Mono-, Bi- and Tricyclic Azacycles
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Bromoenynamides represent precursors to a diversity of azacycles by a cascade sequence of carbopalladation followed by cross-coupling/electrocyclization, or reduction processes. Full details of our investigations into intramolecular ynamide carbopalladation are disclosed, which include the first examples of carbopalladation/cross-coupling reactions using potassium organotrifluoroborate salts; and an understanding of factors influencing the success of these processes, including ring size, and the nature of the coupling partner. Additional mechanistic observations are reported, such as the isolation of triene intermediates for electrocyclization. A variety of hetero-Diels-Alder reactions using the product heterocycles are also described, which provide insight into Diels-Alder regioselectivity.
- Campbell, Craig D.,Greenaway, Rebecca L.,Holton, Oliver T.,Walker, P. Ross,Chapman, Helen A.,Russell, C. Adam,Carr, Greg,Thomson, Amber L.,Anderson, Edward A.
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supporting information
p. 12627 - 12639
(2015/09/01)
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- Novel catalyst system for hydrostannation of alkynes
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A catalyst system was developed for the highly regio-and stereoselective hydrostannation of a range of alkynes with tributylstannane under mild conditions. The active catalytic species was generated from a stable diruthenium complex by illuminating household fluorescent light (30 W) at room temperature.
- Gupta, Sreya,Do, Youngshil,Lee, Jin Hee,Lee, Miryeong,Han, Junghoon,Rhee, Young Ho,Park, Jaiwook
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p. 1267 - 1271
(2014/04/03)
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- A one-pot allylation-hydrostannation sequence with recycling of the intermediate tin waste
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A one-pot allylation and hydrostannation of alkynals where the tin byproduct formed in the first step of the reaction is recycled and used in the second step of the sequence is presented. Specifically, a BF3· OEt2-promoted allylstannation of the aldehyde moiety in the alkynal is followed by the introduction of polymethylhydrosiloxane (PMHS) and catalytic B(C6F5)3, which convert the tin byproduct of the allylation into Bu3SnH, which then hydrostannates the alkyne in the molecule. 119Sn and 11B NMR data suggest an organotin fluoride species is formed during the allylation step and involved in the tin recycling step.
- Ghosh, Banibrata,Amado-Sierra, Maria Del Rosario I.,Holmes, Daniel,Maleczka, Robert E.
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supporting information
p. 2318 - 2321
(2014/05/20)
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- Non-Pd transition metal-catalyzed hydrostannations: Bu3SnF/PMHS as a tin hydride source
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Molybdenum, cobalt, nickel, ruthenium, and rhodium catalyzed alkyne hydrostannations using in situ generated Bu3SnH were studied. In most cases, Bu3SnF+polymethylhydrosiloxane (PMHS) performed well as the in situ source of Bu3/
- Maleczka Jr., Robert E.,Ghosh, Banibrata,Gallagher, William P.,Baker, Aaron J.,Muchnij, Jill A.,Szymanski, Amy L.
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p. 4000 - 4008
(2013/06/27)
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- 2,2′-azobis(2-methylpropionitrile)-mediated alkyne hydrostannylation: Reaction mechanism
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Not as radical as you think: The free-radical hydrostannylation of alkynes has been extensively studied and while every published mechanism involves solely radical intermediates, this appears not to be correct. Trace molecular oxygen is necessary for any radical-mediated hydrostannylation to occur with a wide selection of alkynes, thus leading to a proposed hybrid single-electron transfer/radical propagation mechanism. AIBN=2,2′-azobis(2- methylpropionitrile). Copyright
- Oderinde, Martins S.,Froese, Robert D. J.,Organ, Michael G.
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p. 11334 - 11338
(2013/11/06)
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- NOVEL HEXATRIENE- -CARBONYL COMPOUND
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A label with which labeling is easy when labeling a molecule, i.e., a label that has a high reaction rate upon labeling and that produces a high reaction yield, as well as a precursor for the production of the label are provided. This is achieved by a hex
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Page/Page column 105
(2009/12/23)
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- Lewis acid-catalyzed hydrometalation and carbometalation of unactivated alkynes
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Hydrosilylation, hydrostannation, carbosilylation, and carbostannation of unactivated alkynes with organosilanes, or organostannanes proceed effectively in the presence of catalytic amounts of Lewis acids to produce the corresponding vinylsilyl or vinylst
- Asao, Naoki,Yamamoto, Yoshinori
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p. 1071 - 1087
(2007/10/03)
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- Hydrostannation of C-C multiple bonds with Bu3SnH prepared in situ from Bu3SnCl and Et3SiH in the presence of Lewis acid catalysts
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A number of alkynes 5, allene 11 and alkene 13 smoothly underwent hydrostannation with tributyltin hydride 1, prepared in situ from tributylchlorostannane 6 and triethylsilane 7 in the presence of catalytic amounts of Lewis acids.
- Gevorgyan, Vladimir,Liu, Jian-Xiu,Yamamoto, Yoshinori
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- A new synthesis of iron(0) vinylketene complexes
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Reaction of vinyllithium reagents generated from vinylstannanes [(E)-RCH=CHSnBu3 (R = Ph, SiPh3, SiMe3, n-C5H11), 1a-d] with [Fe(CO)4L] (L = CO, PPh3) followed by an ethyl triflu
- Gibson, Susan E.,Ward, Mark F.,Kipps, Martin,Stanley, Paul D.,Worthington, Paul A.
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p. 263 - 264
(2007/10/03)
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- Lewis Acid Catalyzed trans-Hydrostannylation of Acetylenes
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A Lewis acid such as ZrCl4 or HfCl4 catalyses the hydrostannylation of acetylenes 1 to produce the trans-hydrostannylatiom products 2 regio- and stereo-selectively.
- Asao, Naoki,Liu, Jian-Xiu,Sudoh, Tomoko,Yamamoto, Yoshinori
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p. 2405 - 2406
(2007/10/03)
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- Stannyl-cupration of Acetylenes and the Reaction of the Intermediate Cuprates with Electrophiles as a Synthesis of Substituted Vinylstannanes
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Stannyl-cupration of acetylenes followed by electrophilic attack with a variety of electrophiles gives E-vinylstannanes.These can be used either to form acetylenes, thus achieving overall the addition of an ethynyl group, or to form carbon-carbon bonds in Stille reactions.
- Barbero, Asuncion,Cuadrado, Purificacion,Fleming, Ian,Gonzalez, Ana M.,Pulido, Francisco J.,Rubio, Rosa
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p. 1657 - 1662
(2007/10/02)
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- (Trialkylstannyl)dimethylsilane as a New Precursor of Dimethylsilylene: A Novel Synthesis of 3,4-Disubstituted 1-Silacyclopenta-2,4-dienes
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In the presence of triphenylphosphinepalladium complexes, (trialkylstannyl)dimethylsilane rapidly reacted at room temperature with terminal acetylenes to give 3,4-disubstituted 1-silacyclopenta-2,4-dienes in moderate yield.The formation of 1-silacyclopentadiene derivatives is evidence for the generation of dimethylsilylene species from (trialkylstannyl)dimethylsilane.
- Ikenaga, Kazutoshi,Hiramatsu, Kouji,Nasaka, Norimitsu,Matsumoto, Satoshi
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p. 5045 - 5047
(2007/10/02)
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- The Stannyl-Cupration of Acetylenes and the Reaction of the Intermediate Cuprates with Electrophiles as a Synthesis of Substituted Vinylstannanes
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Stannyl-cupration of acetylenes followed by electrophilic attack with a variety of electrophiles gives vinylstannanes.
- Barbero, Asuncion,Cuadrado, Purificacion,Fleming, Ian,Gonzalez, Ana M.,Pulido, Francisco J.
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p. 351 - 353
(2007/10/02)
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- Regioselective Hydrostannation of Terminal Acetylenes under Transition Metal Catalysis
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Rhodium complexes (RhClL3, RhCl(CO)L2, 2; L = PPh3) catalyze hydrostannation of terminal acetylenes (RCCH; R = Ph, Me3Si, R1OC(R2)R3), and R1OCH2CH2; R1 = THP, OAc; R1, R
- Kikukawa, Kiyoshi,Umekawa, Hideto,Wada, Fumio,Matsuda, Tsutomu
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p. 881 - 884
(2007/10/02)
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- Preparation of vinylstannanes via the Peterson reaction
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The condensation of anions derived from (phenylthio)(tri-n-butylstannyl)(trimethylsilyl)methane (2a), tert-butyl (tri-n-butylstannyl)(trimethylsilyl)acetate (2b), and (tri-n-butylstannyl)(trimethylsilyl)methane (2c) with carbonyl compounds was used to com
- Ager, David J.,Cooke, Glen E.,East, Michael B.,Mole, Susan J.,Rampersaud, Ashraff,Webb, Victoria J.
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p. 1906 - 1908
(2008/10/08)
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- INTERET DE LA DEUTERIATION DES MOLECULES ORGANOSTANNIQUES EN RMN DE 119Sn. I. ACCES AUX CONSTANTES DE COUPLAGE nJ(SnD) ET APPLICATION A L'ETUDE STRUCTURALE DE VINYL ET D'ALLYLETAINS
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The selective deuteration of organotin compounds gives FT 119Sn NMR a new proficiency, since it allows direct access to nJ(SnD) coupling constants.Usually nJ(SnD) is easily apparent for n=1, 2, 3 and sometimes 4 (allyltin compounds).This criterion has been successfully applied for qualitative and subsequently quantitative analysis of vinyltin and allyltin compounds.In the first series, the stereochemistry of alkyne deuterostannation has been easily explored, the assignments of configurations being made directly from 3J(SnD) on the basis of 3J(SnD)trans > 3J(SnD)cis.In the second series, the method appears to be the best tool for simultaneous study of regiochemistry and stereochemistry in the substitution of 3-deutero-5-methyl-2-cyclohexenyl toluene sulphonates by trialkylstannyl anions.The choice between regioisomers was made on the basis of 2J(SnD) > 4J(SnD).A further aspect of this work is the observation of isotopic effects on 119Sn chemical shifts which were tentatively rationalized considering inductive, steric or hyperconjugative contribution of deuterium.
- Quintard, Jean-Paul,Degueil-Castaing, Marie,Dumartin, Gilles,Barbe, Bernard,Petraud, Michel
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- SYNTHESIS OF ORGANOTRIALKYLSTANNANES. THE REACTION BETWEEN ORGANIC HALIDES AND HEXAALKYLDISTANNANES IN THE PRESENCE OF PALLADIUM COMPLEXES
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The aryl halides YC6H4X (X=Br or I) have been shown to react with the distannanes (R3Sn)2 (R=n-Bu or Me) in toluene in the presence of or to give the compounds YC6H4SnR3 for (a) R=n-Bu, Y=H, p-OMe, o-Me, p-Me, m-Cl, p-Cl, m-CN, p-COCH3 and m-NO2, and (b) R=Me, Y=H, p-OMe, p-Me, p-CN, p-COCH3, m-NO2 and p-NO2.Benzyl halides YC6H4CH2X (X=Cl or Br) similarly give YC6H4CH2SnR3 for (a) R=n-Bu, Y=H, m-OMe, p-OMe, m-Cl, m-CN, and m-NO2, and (b) R=Me, Y=m-Cl, m-CN, p-CN and m-NO2.These reactions are of special value as preparative procedures in cases in which Grignard or organolithium reagents cannot be used.Allyl chloride and bromide were likewise shown to react with (n-Bu3Sn)2 to give CH2=CHCH2SnBu3, but n-BuCl and n-BuBr gave only a trace of n-Bu4Sn.The mixed dimetallo species n-Bu3SnSiMe3 was shown to react with aryl bromides YC6H4Br (X=H, p-OMe, p-Me, or p-Cl) to give the arylsilicon compounds YC6H4SiMe3, with no aryltin products.
- Azizian, Hormoz,Eaborn, Colin,Pidcock, Alan
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