- ALLYLSTANNATION. II. A TOTAL "cis-PREFERENCE" IN THE ADDITION OF n-Bu2ClSnCH(CH3)CH=CH2 TO ALDEHYDES
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1-Buten-3-yldi-n-butylchlorotin, formed by redistribution of (E/Z)-2-butenyltri-n-butyltin and Bu2SnCl2, reacts readily with neat RCHO (R = C2H5, C2H5(CH3)CH, (CH3)2CH, (CH3)3C and C6H5) to give high yields (80-100percent) of alcohols of the type RCH(OH)C
- Gambaro, Alessandro,Ganis, Paolo,Marton, Daniele,Peruzzo, Valerio,Tagliavini, Giuseppe
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Read Online
- Bismuth mediated barbier synthesis of α-homoallylic alcohols via a sigmatropic rearrangement in [bmim][HSO4]
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A novel protocol for the Bismuth metal mediated regioselctive crotylation of aldehydes yielding α-homoallylic alcohols has been developed using 20mol% [bmim][HSO4] as a metal activator, as well as a mediator for regioconversion from the initially formed γ-regiomer. The present protocol minimizes the use of conventional solvents and proceeds with good yields and excellent regioselectivities.
- Chatterjee, Sucheta,Dey, Papiya,Kanojia, Seema V.,Chattopadhyay, Subrata,Goswami, Dibakar
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supporting information
p. 765 - 775
(2020/12/13)
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- Nickel-catalyzed remote hydrosilylation of unconjugated enones with bulky triphenylsilane
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Herein we describe a nickel-catalyzed remote hydrosilylation of unconjugated enones with bulky triphenylsilane. A range ofZ-silyl enol ethers are obtained as major isomers due to the process of nickel triggered alkene isomerization. Notably, some specific
- Chen, Xue,Jin, Hongwei,Liu, Yunkui,Wang, Zhen,Zhou, Bingwei,Zhou, Jinyong
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supporting information
p. 8021 - 8024
(2021/10/04)
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- Palladium-catalyzed double-bond migration of unsaturated hydrocarbons accelerated by tantalum chloride
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The operationally simple palladium-catalyzed double-bond migration without heteroatom-containing coordinating functional groups is described. Addition of TaCl5 as a second catalyst greatly enhanced the migration efficiency to provide β-alkylsty
- Murai, Masahito,Nishimura, Kengo,Takai, Kazuhiko
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supporting information
p. 2769 - 2772
(2019/03/23)
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- Indium-mediated allylation of carbonyl compounds in ionic liquids: Effect of salts in ionic liquids
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The In-mediated allylation of carbonyl compounds can be performed in various types of solvents including ionic liquids. However, we have found that in [bmim][BF4] (where bmim = 1-butyl-3-methylimidazolium), the In-mediated coupling of crotyl bromide with benzaldehyde gives a complex mixture, and some additives, such as halides and amines, are crucial for the successful conversion to the corresponding γ-adduct. Instead, the addition of alcohols or water promotes the formation of the α-adduct. An asymmetric induction with up to 62% enantiomeric excess (ee) was observed employing cinchonidine as an additive in a binary solvent consisting of an ionic liquid and dichloromethane.
- Hirashita, Tsunehisa,Takahashi, Fusako,Noda, Takayuki,Takagi, Yuji,Araki, Shuki
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- Hot water-promoted cyclopropylcarbinyl rearrangement facilitates construction of homoallylic alcohols
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In refluxing 9 : 1 (v/v) H2O-1,4-dioxane and without an additional catalyst, the rearrangements of various types of cyclopropyl carbinols were attempted. It was found that the reactions generally gave homoallylic alcohols in good to very high chemical yields. Rearrangements of bicyclic or tricyclic cyclopropyl carbinols readily gave the desired ring-expanded cyclic homoallylic alcohols which are difficult to synthesize by other means.
- Li, Pei-Fang,Yi, Cheng-Bo,Qu, Jin
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p. 5012 - 5021
(2015/05/05)
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- Prins cyclization of α-bromoethers under basic conditions
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α-Bromoethers have been found to undergo Prins-type cyclization under basic conditions and without the need to add a promoter. The products are those derived from a Markovnikov addition on the pendant alkene. However, the stereochemistry and even the structure of the products sometimes differ from those expected with the classical Lewis-acid-catalyzed Prins reaction of acetals.
- Arpin, Patrice,Hill, Bryan,Larouche-Gauthier, Robin,Spino, Claude
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supporting information
p. 1193 - 1201
(2014/01/06)
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- Highly stereoselective synthesis of z-homoallylic alcohols by kinetic resolution of racemic secondary allyl boronates
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α to Z: Racemic α-chiral allyl boronates, which are readily synthesized from the respective primary allyl halides, undergo a highly efficient kinetic resolution in a face- and Z-selective allylation of aldehydes catalyzed by the chiral Bronsted acid (R)-TRIP (see scheme; Epin=tetraethylethylene glycol). Copyright
- Incerti-Pradillos, Celia A.,Kabeshov, Mikhail A.,Malkov, Andrei V.
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supporting information
p. 5338 - 5341
(2013/06/05)
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- Allylation reactions of aldehydes with allylboronates in aqueous media: Unique reactivity and selectivity that are only observed in the presence of water
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Zn(OH)2-catalyzed allylation reactions of aldehydes with allylboronates in aqueous media have been developed. In contrast to conventional allylboration reactions of aldehydes in organic solvents, the α-addition products were obtained exclusively. A catalytic cycle in which the allylzinc species was generated through a B-to-Zn exchange process is proposed and kinetic studies were performed. The key intermediate, an allylzinc species, was detected by HRMS (ESI) analysis and by online continuous MS (ESI) analysis. This analysis revealed that, in aqueous media, the allylzinc species competitively reacted with the aldehydes and water. An investigation of the reactivity and selectivity of the allylzinc species by using several typical allylboronates (6a, 6b, 6c, 6d) clarified several important roles of water in this allylation reaction. The allylation reactions of aldehydes with allylboronic acid 2,2-dimethyl-1,3-propanediol esters proceeded smoothly in the presence of catalytic amounts of Zn(OH)2 and achiral ligand 4d in aqueous media to afford the corresponding syn-adducts in high yields with high diastereoselectivities. In all cases, the α-addition products were obtained and a wide substrate scope was tolerated. Furthermore, this reaction was applied to asymmetric catalysis by using chiral ligand 9. Based on the X-ray structure of the Zn-9 complex, several nonsymmetrical chiral ligands were also found to be effective. This reaction was further applied to catalytic asymmetric alkylallylation, chloroallylation, and alkoxyallylation processes and the synthetic utility of these reactions has been demonstrated. Still waters run deep: The Zn(OH)2-catalyzed allylation of aldehydes with allylboronates in aqueous media exclusively afford the α-addition products. This reaction was also applied to alkylallylation, chloroallylation, and alkoxyallylation reactions. The role of water is discussed. Copyright
- Kobayashi, Shu,Endo, Toshimitsu,Yoshino, Takumi,Schneider, Uwe,Ueno, Masaharu
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supporting information
p. 2033 - 2045
(2013/09/23)
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- Cobalt-salen complex-catalyzed oxidative generation of alkyl radicals from aldehydes for the preparation of hydroperoxides
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Catalytic generation of alkyl radicals from aldehydes via oxidative deformylation was realized using a cobalt-salen complex with H2O 2. The deformylation was thought to proceed through homolytic cleavage of peroxohemiacetal intermediates to provide even primary alkyl radicals under mild conditions. Variously substituted and functionalized hydroperoxides were obtained from corresponding aldehydes in good yield.
- Watanabe, Eiichi,Kaiho, Atsushi,Kusama, Hiroyuki,Iwasawa, Nobuharu
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supporting information
p. 11744 - 11747
(2013/09/02)
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- High regiocontrol in the zinc-mediated crotylation of aldehydes and ketones: A straightforward and facile approach to linear homoallylic alcohols in DMPU
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The α-regioselectivity of carbonyl crotylation is a long-standing problem in the realm of C-C bond formation reactions. We demonstrate that zinc-mediated crotylation of aldehydes and ketones can afford α-linear homoallylic alcohols exclusively to provide
- Zhao, Li-Ming,Wan, Li-Jing,Jin, Hai-Shan,Zhang, Shu-Qing
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scheme or table
p. 2579 - 2584
(2012/06/04)
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- Intramolecular nucleophilic attack at silicon in o-silylbenzyl alcohols. Generation of allyl and benzyl anion equivalents
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Substituted silyl ethers of o-bromobenzyl alcohols and the derived o-silylbenzyl alcohols were used to transfer allyl and benzyl groups from silicon to the electrophiles benzaldehyde and benzophenone in excellent yields. γ-Oxidosilane intermediates (and possibly hypercoordinated silicon intermediates) are postulated.
- Hudrlik, Paul F.,Hudrlik, Anne M.,Jeilani, Yassin A.
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experimental part
p. 10089 - 10096
(2012/02/13)
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- Titanocene(III)-promoted Barbier-type crotylation of carbonyl compounds
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A mild, highly regio-and stereoselective method for the crotylation of aldehydes and ketones mediated/catalyzed by titanocene(III) is described. Optimized conditions permit the selective generation of γ-adducts in high yields together with high stereoselectivity, with a predominance of anti stereoisomers.
- Sancho-Sanz, Iris,Miguel, Delia,Millan, Alba,Estevez, Rosa E.,Oller-Lopez, Juan L.,Alvarez-Manzaneda, Enrique,Robles, Rafael,Cuerva, Juan M.,Justicia, Jose
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experimental part
p. 732 - 735
(2011/03/20)
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- Aldehyde allylation with allylboronates providing α-addition products
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Zn(OH)2-catalyzed allylation reactions of allylboronates with aldehydes proceeded smoothly in aqueous media; when α-substituted allylboronates were employed, the α-addition products were obtained exclusively, and syn-adducts were formed selecti
- Kobayashi, Shu,Endo, Toshimitsu,Schneider, Uwe,Ueno, Masaharu
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scheme or table
p. 1260 - 1262
(2010/07/05)
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- The catalyzed desulfinylative allylation of carbonyl compounds with alk-2-enesulfonyl chlorides and silyl alk-2-enesulfinates
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Coupling up with sulfonyl chlorides: An ene reaction of alkenes with SO2·BCl3 permits the one-pot conversion of simple alkenes into b,g-unsaturated sulfonyl chlorides or sulfinic silyl esters. These compounds can then be used as nucleophilic allylating agents with aldehydes and ketones to generate the corresponding homoallylic alcohols (see scheme) with good chemo-and diastereoselectivity in the presence of a suitable catalyst and reducing agent.
- Volla, Chandra M. R.,Markovic, Dean,Laclef, Sylvain,Vogel, Pierre
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supporting information; experimental part
p. 8984 - 8988
(2010/10/02)
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- Silver oxide as a novel catalyst for carbon-carbon bond-forming reactions in aqueous media
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Silver oxide was found to be an excellent catalyst for allylation reactions of allyltributyltins with aldehydes in aqueous media. Despite the very low solubility of silver oxide in the media, the reactions proceeded smoothly, and the catalyst was recovere
- Ueno, Masaharu,Tanoue, Arata,Kobayashi, Shu
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supporting information; experimental part
p. 652 - 653
(2011/01/10)
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- Synthesis, characterization and primary evaluation of the synthetic efficiency of supported vinyltins and allyltins
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Supported vinyltins and allyltins grafted to an insoluble cross-linked polystyrene matrix were prepared using methods usually employed in solution, like hydrostannylation of alkynes, transmetallation of a tin halide with organomagnesium or organozinc reagents, and substitution of an allyl halide by a supported stannylanion or SN2′ substitution of a supported β-stannylacrolein acetal by cyanocopper reagents in the presence of boron trifluoride etherate. The insoluble grafted organotin reagents were analysed by HRMAS NMR, allowing an unambiguous assignment of their isomeric distribution or the identification of side products. When involved in Stille cross-coupling reactions (vinyltins) or in addition on aldehydes (allyltins), these supported reagents exhibit similar reactivity and similar stereoselectivity when compared to the tributyltin analogues, with the advantage to prevent problems due to the contamination by tin residues.
- Kerric, Gaelle,Grognec, Erwan Le,Fargeas, Valérie,Zammattio, Fran?oise,Quintard, Jean-Paul,Biesemans, Monique,Willem, Rudolph
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experimental part
p. 1414 - 1424
(2010/07/04)
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- Crotylation of aldehydes by crotyltins: Discrimination between mechanisms involving transmetallation or simple lewis acid assistance through the consideration of the stereochemistry of the corresponding homoallylic alcohols
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In the reaction of crotyltins with aldehydes in the presence of metal salts, the double consideration of the syn/anti ratio of the branched homoallylic alcohols and the Z/E ratio of their linear regioisomers is proposed as a way to discriminate between a reaction mechanism involving a transmetallation step and a reaction mechanism involving simple Lewis acid activation of the aldehyde. The formation of branched syn isomers along with Z-linear isomers as major compounds is considered to be indicative of a reaction occurring under Lewis acid assistance, whereas preference for the branched anti isomers together with E-linear isomers is considered to be indicative of a transmetallation step prior to crotylation. For reactions performed in the presence of CeCl3·7H2O/NaI, the Lewis acid assistance was shown to be the exclusive or highly prevalent pathway. Moreover, in regards to the selectivity, the regiopreference depends on the nature of the crotyltin. Whereas soluble crotyltin preferentially leads to Z-linear adducts, polymer-supported crotyltin affords the syn-branched adducts probably due to a lower 1,3-metallotropy. For reactions performed in the presence of InX 3, simple Lewis acid assistance and transmetallation appear to be competitive processes; the first one is favoured with aromatic aldehydes especially in dichloromethane, whereas transmetallation appears to be prevalent with poorly reactive aldehydes especially with InBr3 in acetonitrile. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Fargeas, Valerie,Zammattio, Francoise,Chretien, Jean-Mathieu,Bertrand, Marie-Jo,Paris, Michael,Quintard, Jean-Paul
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scheme or table
p. 1681 - 1688
(2009/04/07)
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- Gallium-mediated allyl transfer from bulky homoallyl alcohol to aldehydes or alkynes: Control of dynamic σ-allylgalliums based on retro-allylation reaction
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A new method for the preparation and control of dynamic σ-allylgalliums is disclosed. Upon treatment with a Grignard reagent and gallium trichloride, bulky homoallyl alcohols undergo gallium-mediated retro-allylation reaction to provide σ-allylgallium reagents. The σ-allylgallium reagents generated were applied to carbonyl allylation. The retro-allylation reaction generates (Z)- and (E)-σ-crotylgalliums stereospecifically, starting from erythro- and threo-homoallyl alcohols, respectively. The stereochemically defined crotylgallium reagents effected stereoselective allylation of aldehydes. Allylgallation reaction of alkynes with the allylgallium reagents prepared by retro-allylation is also described.
- Hayashi, Sayuri,Hirano, Koji,Yorimitsu, Hideki,Oshima, Koichiro
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p. 505 - 513
(2008/02/06)
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- SnCl2-mediated carbonyl allylation of aldehydes and ketones in ionic liquid
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In ionic liquid [bmim]BF4, SnCl2·2H 2O acts as an inexpensive and efficient metal salt for carbonyl allylation. By applying ionic liquid, some previously reported serious operational problems associated with the SnCl2-mediated allylation reaction are avoided. Furthermore, ketones, which are less reactive than aldehydes, can also be allylated in high yields with this system.
- Tang, Long,Ding, Li,Chang, Wei-Xing,Li, Jing
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p. 303 - 306
(2007/10/03)
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- Iridium-catalyzed carbonyl allylations by allylic alcohols with Tin(II) chloride
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Iridium complex [IrCl(cod)]2 can function as a catalyst for the allylation of aldehydes and ketones by allylic alcohols upon addition of an equimolar amount of SnCl2 in THF-H2O; the reaction is carried out between room temperature and 50 °C to give the corresponding homoallylic alcohols. Georg Thieme Verlag Stuttgart.
- Masuyama, Yoshiro,Chiyo, Toshiya,Kurusu, Yasuhiko
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p. 2251 - 2253
(2007/10/03)
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- Synthesis of 4-substituted homoallylic alcohols via a one-pot tandem Lewis-acid catalyzed crotylboration-[3,3]-sigmatropic rearrangement
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Crotylboration of aldehydes with E- or Z-crotylboronates in the presence of catalytic amounts of indium triflate provides the corresponding 4-substituted homoallylic alcohols. The Royal Society of Chemistry 2005.
- Ramachandran, P. Veeraraghavan,Pratihar, Debarshi,Biswas, Debanjan
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p. 1988 - 1989
(2007/10/03)
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- Allylation of aldehydes promoted by the cerium(III) chloride heptahydrate/sodium iodide system: The dependence of regio- and stereocontrol on the reaction conditions
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The cerium(III) chloride heptahydrate/sodium iodide complex (CeCl 3·7 H2O/NaI) acts as a useful promoter in the carbon-carbon bond forming reaction by addition of allyltributylstannanes to aldehydes. The reaction of 2-butenyltributyl
- Bartoli,Giuliani,Marcantoni,Massaccesi,Melchiorre,Lanari,Sambri
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p. 1673 - 1680
(2007/10/03)
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- Efficient allylation of aldehydes promoted by carboxylic acids
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A variety of carboxylic acids have been screened for mediating the allylation of aldehydes with allytributyltin in different solvents. A novel, general, and practical method of allylation of aldehydes promoted by carboxylic acids under mild reaction condi
- Li, Gui-Long,Zhao, Gang
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p. 4272 - 4278
(2007/10/03)
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- Rh-catalyzed enantioselective diboration of simple alkenes: Reaction development and substrate scope
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The rhodium-catalyzed reaction between bis(catecholato)diboron and simple alkenes results in the syn addition of the diboron across the alkene. The resulting 1,2-bis(boronate) is subsequently oxidized to provide the 1,2-diol. In the presence of enantiomerically enriched Quinap ligand, high enantioselection in the diboration can be achieved. The reaction is highly selective for trans- and trisubstituted alkenes and can be selective for some monosubstituted alkenes as well. The development of this reaction is described as is the substrate scope and experiments that are informative about the reaction mechanism and competing pathways.
- Trudeau, Stephane,Morgan, Jeremy B.,Shrestha, Mohanish,Morken, James P.
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p. 9538 - 9544
(2007/10/03)
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- Barbier-type reaction mediated with tin nano-particles in water
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Tin nano-particles are employed in the Barbier-type allylation reaction of carbonyl compounds in water to afford the corresponding homoallylic alcohols in good yields. The in situ generated allylation intermediates, allyltin(II) bromide and diallyltin dib
- Zha, Zhenggen,Qiao, Shu,Jiang, Jiaoyang,Wang, Yusong,Miao, Qian,Wang, Zhiyong
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p. 2521 - 2527
(2007/10/03)
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- A recyclable electrochemical allylation in water
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(Chemical Equation Presented) To develop environmentally benign processes for C-C bond formation, electrochemistry is applied in a tin-mediated allylation reaction in water. In this electrochemical process, the corresponding homoallylic alcohols are prepa
- Zha, Zhenggen,Hui, Ailing,Zhou, Yuqing,Miao, Qian,Wang, Zhiyong,Zhang, Hanchang
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p. 1903 - 1905
(2007/10/03)
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- Rhodium-catalyzed carbonyl allylations by allylic alcohols with tin(II) chloride
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Rhodium complexes such as [RhCl(cod)]2, [Rh(cod) 2]BF4, and [Rh(cod)(CH3CN)2]BF 4 function as catalysts for carbonyl allylations by allylic alcohols with 1 equimolar amount of tin(II) chlor
- Masuyama, Yoshiro,Kaneko, Yusuke,Kurusu, Yasuhiko
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p. 8969 - 8971
(2007/10/03)
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- Allylation of carbonyl compounds mediated by nanometer-sized bismuth in water
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It is found that nanometer-sized bismuth mediates the allylation of carbonyl compounds in water to afford the corresponding homoallylic alcohol in high yields. Nanometer-sized bismuth is much more effective than regular bismuth powder in this reaction.
- Xu, Xiaolan,Zha, Zhenggen,Miao, Qian,Wang, Zhiyong
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p. 1171 - 1174
(2007/10/03)
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- SnCl2-mediated carbonyl allylation in fully aqueous media
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Systematic studies were performed on SnCl2-mediated carbonyl allylation reaction between aldehydes and allyl halides in fully aqueous media. Totally three valuable reaction systems were discovered, which were SnCl 2/CuCl2, SnCl2/TiCl3, and SnCl 2/PdCl2. They all provided good to excellent yields in the allylation of aliphatic and aromatic aldehydes under very mild and convenient conditions. SnCl2, by itself, was also found to be effective for the allylation reaction when allyl bromide was employed. However, the SnCl 2-only reaction could only tolerate very small amount of water as the solvent. The SnCl2/CuCl2, SnCl2/TiCl 3, and SnCl2/PdCl2-mediated reactions exhibited good regioselectivity favoring the γ-adduct when cinnamyl halides were employed as the allylation reagent. The same reactions with cinnamyl halides also showed good diastereoselectivity favoring the anti-product. Mechanistic studies using proton NMR techniques suggested that the additive (i.e., CuCl 2, TiCl3, PdCl2) could accelerate the formation of allyltin intermediate, but this step was shown not to be the most important for the allylation. Thus we proposed that the Lewis acid catalysis effect exerted by the additive was the main reason for the observed reactivity enhancement.
- Tan, Xiang-Hui,Hou, Yong-Quan,Huang, Chao,Liu, Lei,Guo, Qing-Xiang
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p. 6129 - 6136
(2007/10/03)
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- Regioselective allylation reactions using crotyl Grignard reagent-CeCl3 systems
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Regioselective allylation reactions using crotyl Grignard reagent-CeCl3 systems are described. Regioselectivity depends on the lanthanide salts: α-product was predominantly produced with light rare earth elements such as La, Ce, Pr, Nd, whereas
- Matsukawa, Satoru,Funabashi, Yohei,Imamoto, Tsuneo
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p. 1007 - 1010
(2007/10/03)
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- High regio- and stereoselective Barbier reaction of carbonyl compounds mediated by NaBF4/Zn (Sn) in water
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Studies with NaBF4/M (M = Zn or Sn) showed that this novel mediator facilitated allylation of a variety of carbonyl compounds in water and had a great influence on the diastereoselectivity of the addition. More importantly, α- and γ-addition pr
- Zha, Zhenggen,Xie, Zhen,Zhou, Cunliu,Chang, Mingxin,Wang, Zhiyong
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p. 1297 - 1300
(2007/10/03)
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- Mechanistic studies on the catalytic cycle of metal fluoride-catalyzed allylation using allyltrimethoxysilane in protic solvents
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The catalytic cycles of CdF2·1-catalyzed and AgF·BINAP-catalyzed allylation using allyltrimethoxysilane in protic solvents were investigated. The experimental and 19F NMR studies strongly supported that metal fluorides were regenerat
- Aoyama, Naohiro,Hamada, Tomoaki,Manabe, Kei,Kobayashi, Shu
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p. 7329 - 7333
(2007/10/03)
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- Allylic-type diindium reagents. Reactivity toward electrophiles and cascade coupling reactions with imines
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The allylic-type diindium reagents A and B were prepared from 3-bromo-1-iodopropene (1a) and 4-bromo-2-iodobut-2-ene (1b), respectively, and their reactions with electrophiles were investigated. The diindium reagents A and B were initially reacted with im
- Hirashita, Tsunehisa,Hayashi, Yousuke,Mitsui, Kazuma,Araki, Shuki
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p. 1309 - 1313
(2007/10/03)
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- Development of a highly α-regioselective metal-mediated allylation reaction in aqueous media: New mechanistic proposal for the origin of α-homoallylic alcohols
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This paper described a general method to obtain α-adduct homoallylic alcohols using indium, zinc, and tin in water. A new mechanism was proposed to account for the formation of these synthetically difficult-to-obtain molecules. Generally, this method can
- Tan, Kui-Thong,Chng, Shu-Sin,Cheng, Hin-Soon,Loh, Teck-Peng
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p. 2958 - 2963
(2007/10/03)
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- Allylation of carbonyl compounds with allylic gallium reagents
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Allylic gallium reagents, prepared from gallium trichloride and the corresponding allylic Grignard reagents, allylated carbonyl compounds in good yields in an aqueous medium as well as in organic solvent.
- Tsuji, Takashi,Usugi, Shin-ichi,Yorimitsu, Hideki,Shinokubo, Hiroshi,Matsubara, Seijiro,Oshima, Koichiro
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- Preparation of organomanganese reagents from organic halides with activated manganese
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Reduction of Li2MnCl4 with magnesium metal provided activated manganese as a black suspension in THF. Treatment of organic halides such as allyl bromides, α-halo esters or aryl halides with activated manganese furnished various organomanganese reagents which reacted further with electrophiles to afford the corresponding adducts. The reaction of a ketone bearing an iodoaryl moiety with this active manganese induced cyclization to provide dihydroindene derivative.
- Kakiya, Hirotada,Nishimae, Shinji,Shinokubo, Hiroshi,Oshima, Koichiro
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p. 8807 - 8815
(2007/10/03)
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- A novel preparation of allylic trichlorotins from α,α-diisopropylhomoallylic alcohols and its application to carbonyl allylations
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α,α-Diisopropylhomoallylic alcohols react with tin(II) chloride and NCS in CH2Cl2 at -40 °C to -60 °C to produce allylic tins and diisopropyl ketone, and the allylic tins in situ cause nucleophilic addition to aldehydes to afford α-s
- Masuyama,Saeki,Horiguchi,Kurusu
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p. 1802 - 1804
(2007/10/03)
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- Development of a highly α-regioselective indium-mediated allylation reaction in water
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Linear α homoallylic alcohol adducts were obtained with high regioselectivities in moderate to good yields using allylic indium reagents in the presence of 10 M water. The exceptionally high regioselectivities observed were neither steric nor electronic i
- Loh, Teck-Peng,Tan, Kui-Thong,Yang, Jian-Ying,Xiang, Chao-Li
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p. 8701 - 8703
(2007/10/03)
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- Electrochemical regeneration of low-valent indium(I) species as catalysts for C-C bond formations
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It seems almost paradoxical that reactive low-valent indium(I) species can be generated at the anode through reduction of indium(III) salts under electrochemical conditions (see scheme). The resulting indium(I) species are highly effective catalysts for the allylation of different aldehydes, ketones, and esters on a preparative scale.
- Hilt, Gerhard,Smolko, Konstantin I.
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p. 3399 - 3402
(2007/10/03)
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- New and stereoselective synthesis of 1,4-disubstituted buten-4-ols (homoallylic alcohol α-adducts) from the corresponding γ-isomers (3,4-disubstituted buten-4-ols) via an acid-catalyzed allyl-transfer reaction with aldehydes
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The γ-adducts of homoallylic alcohols 3, derived from aldehydes via the usual reaction with common allylic metals 1, were converted to the corresponding α-adducts 6 by an acid-catalyzed allyl-transfer reaction. In the allyl-transfer reaction, anti-and syn
- Sumida, Shin-Ichi,Ohga, Masanori,Mitani, Junji,Nokami, Junzo
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p. 1310 - 1313
(2007/10/03)
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- Regio- and diastereocontrol in carbonyl allylation by 1-halobut-2-enes with tin(II) halides
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Regio- and diastereoselective carbonyl allylations of 1-halobut-2-enes with tin(II) halides are described. Tin(II) bromide in a dichloromethane- water biphasic system is an effective reagent for unusual α-regioselective carbonyl allylation of 1-bromobut-2
- Ito, Akihiro,Kishida, Masayuki,Kurusu, Yasuhiko,Masuyama, Yoshiro
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p. 494 - 498
(2007/10/03)
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- Lipase-catalyzed kinetic resolution of Z-configured homoallylic alcohols
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Racemic Z homoallylic alcohols were prepared by the BuSnCl3-catalyzed addition of aldehydes to 1-(tributylstannyl)-2-butene. These alcohols were resolved for the first time by lipase-catalyzed enantioselective acetylation in up to 98% enantiomeric purity.
- Adam, Waldemar,Saha-Moeller, Chantu R.,Schmid, Katharina S.
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p. 315 - 322
(2007/10/03)
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- Hypersensitive radical probe studies of chloroperoxidase-catalyzed hydroxylation reactions
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The oxidation of hypersensitive radical probes by chloroperoxidase from Caldariomyces fumago (CPO) was studied in an attempt to 'time' a putative radical intermediate. Oxidation of (trans-2-phenylcyclopropyl)methane, previously studied by Zaks and Dodds [Zaks, A., and Dodds, D. R. (1995) J. Am. Chem. Soc. 115, 10419-10424] was reinvestigated. Unrearranged oxidation products were found as previously reported, and control experiments demonstrated that the cyclic alcohol from oxidation at the cyclopropylcarbinyl position, while subject to further oxidation, survives CPO oxidation as detectable species. However, in contrast to the report by Zaks and Dodds, the rearranged alcohol product expected from ring opening of a cyclopropylcarbinyl radical intermediate was shown to be unstable toward the enzyme oxidation reaction. Because of this instability, two new hypersensitive radical probes, (trans-2-phenylcyclopropyl)ethane and 2- (trans-2-phenylcyclopropyl)propane, and their potential cyclic and acyclic products from oxidation at the cyclopropylcarbinyl position were synthesized and tested. Oxidation of both of these probes at the cyclopropylcarbinyl position by CPO gave unrearranged alcohol products only, but control experiments again demonstrated that the rearranged alcohol products were unstable toward CPO oxidation conditions. From the combination of the probe and control studies, the lifetime of a putative radical intermediate must be less than 3 ps. Whereas the results are consistent with an insertion mechanism for production of alcohol product, they do not exclude a very short-lived intermediate.
- Toy, Patrick H.,Newcomb, Martin,Hager, Lowell P.
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p. 816 - 823
(2007/10/03)
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- Regioselective reaction of allylbenzotriazoles with aldehydes and ketones in the presence of lithium
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The reactions of α- and γ-substituted allylbenzotriazoles 2, 3 and 4 with an excess of lithium in THF at -78°C generate various allyllithiums, which react readily with aldehydes and ketones with high regioselectivity to give predominantly the branched products 5 in excellent yields.
- Katritzky, Alan R.,Fali, Clara N.,Qi, Ming
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p. 363 - 366
(2007/10/03)
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- Barbier-type carbonyl-allylation with allyl compounds and SnCl2 in the presence of PdCl2[PPh2(m-C6H4SO 3Na)]2 under two-phase conditions
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The hydrophilic palladium complex efficiently catalyzes the allylation of carbonyl compounds with allyl chlorides or allyl alcohols and SnCl2 under aqueous-organic biphase conditions, which allow us easily to separate the product and to recover the organic solvent from the reaction mixture.
- Okano, Tamon,Kiji, Jitsuo,Doi, Takanori
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- Dimethyldioxirane hydroxylation of a hypersensitive radical probe: Supporting evidence for an oxene insertion pathway
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Dimethyldioxirane oxidation of the hypersensitive radical probe (trans- 2-phenylcyclopropyl)ethane gave non-rearranged hydroxylation products consistent with an oxene insertion mechanism for the reaction.
- Simakov, Pavel A.,Choi, Seung-Yong,Newcomb, Martin
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p. 8187 - 8190
(2007/10/03)
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- Synthesis of homoallylic (but-3-enylic) alcohols from aldehydes with allylic chlorides, tin(II) chloride and potassium iodide in water
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Homoallylic (but-3-enylic) alcohols have been prepared in good yields by reductive allylation of aldehydes in water with various allylic chlorides in the presence of tin(II) chloride and potassium iodide. The Barbier type reaction with prop-2-ynyl chloride is also achieved under the same conditions.
- Houllemare, Didier,Outurquin, Francis,Paulmier, Claude
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p. 1629 - 1632
(2007/10/03)
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- Palladium-catalyzed carbonyl allylation of aldehydes with allylic phosphates: Synthesis of homoallylic alcohols
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Allylation of aldehydes by reaction allylic phosphates with diethylzinc in the presence of Pd(PPh3)4 afforded homoallylic alcohol via nucleophilic allylzinc species.
- Kang, Suk-Ku,Kim, Dae-Yeun,Hong, Ryung-Kee,Ho, Pil-Su
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p. 1493 - 1498
(2007/10/03)
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