- Illuminatinganti-hydrozirconation: controlled geometric isomerization of an organometallic species
-
A general strategy to enable the formalanti-hydrozirconation of arylacetylenes is reported that mergescis-hydrometallation using the Schwartz Reagent (Cp2ZrHCl) with a subsequent light-mediated geometric isomerization atλ= 400 nm. Mechanistic delineation of thecontra-thermodynamic isomerization step indicates that a minor reaction product functions as an efficientin situgenerated photocatalyst. Coupling of theE-vinyl zirconium species with an alkyne unit generates a conjugated diene: this has been leveraged as a selective energy transfer catalyst to enableE→Zisomerization of an organometallic species. Through anUmpolungmetal-halogen exchange process (Cl, Br, I), synthetically useful vinyl halides can be generated (up toZ?:?E= 90?:?10). This enabling platform provides a strategy to access nucleophilic and electrophilic alkene fragments in both geometric forms from simple arylacetylenes.
- Gilmour, Ryan,Hostmann, Theresa,Nevesely, Tomá?
-
p. 10643 - 10648
(2021/08/20)
-
- Alkenylation and Arylation of Peptides via Ni-Catalyzed Reductive Coupling of α- C-Tosyl Peptides with Csp2Triflates/Halides
-
A Ni-catalyzed reductive cross-coupling between α-C-tosyl peptides and Csp2 triflates/halides has been developed. This protocol enables the formation of various unnatural di- and tripeptides containing vinyl and aryl side chains, and it expands the applications of Ni-catalyzed reductive cross-coupling in late-stage diversification of peptides.
- Chen, Yunrong,Gong, Hegui,Ma, Guobin,Qian, Qun,Song, Yanhong,Sun, Deli,Tao, Xianghua
-
supporting information
p. 7418 - 7422
(2021/10/12)
-
- A Simplified Protocol for the Stereospecific Nickel-Catalyzed C-S Vinylation Using NiX 2 Salts and Alkyl Phosphites
-
A Ni-catalyzed C-S cross-coupling using only NiI 2 (0.5-2.5 molpercent) and P(O i Pr) 3 (2.0-10.0 molpercent) is reported. Using an air-stable Ni(II) precatalyst, and a cheap and commercially available ligand, a scalable and robust method was developed to cross-couple various thiophenols and styryl bromides, including some sterically encumbered thiols, an α-bromocinnamaldehyde as well as a thiolation-cyclization.
- Larin, Egor M.,Lautens, Mark,Marchese, Austin D.,Mirabi, Bijan
-
p. 311 - 319
(2019/12/28)
-
- The hydrodebromination of 1,1-dibromoalkenes via visible light catalysis
-
Vinyl bromides are versatile synthetic intermediates and widely applied in organic synthesis and pharmaceuticals. Herein, a hydrodebromination reaction of 1,1-dibromoalkenes was established via visible light catalysis. A variety of structurally different vinyl bromides were obtained in moderate to excellent yields.
- Sun, Wencheng,Teng, Qiaoling,Cheng, Dongping,Li, Xiaonian,Xu, Xiaoliang
-
supporting information
(2019/12/05)
-
- Zirconium-Catalyzed Synthesis of Alkenylaminoboranes: From a Reliable Preparation of Alkenylboronates to a Direct Stereodivergent Access to Alkenyl Bromides
-
A simple procedure has been optimized for the preparation of alkenylaminoborane from alkynes using diisopropylaminoborane and HZrCp2Cl. Coupled with a magnesium-catalyzed dehydrogenation, it allowed for the use of air- and moisture-stable diisopropylamine. This synthesis has been extended to a one-pot sequence leading directly to bromoalkenes with controlled stereochemistry. As such, it provides an easy, scalable, cheap process to access alkenylboronates and both (E)- and (Z)-bromoalkenes from commercially available alkynes.
- Birepinte, Mélodie,Chabaud, Laurent,Liautard, Virginie,Pucheault, Mathieu
-
supporting information
p. 2838 - 2843
(2020/04/16)
-
- Method for synthesizing beta-bromostyrene through metal-free catalysis
-
The invention discloses a method for synthesizing beta-bromostyrene through metal-free catalysis, and belongs to the technical field of organic chemistry. Substituted styrene 1 is used as a raw material and is reacted in the presence of a bromination reagent, sodium persulfate and dichloroethane, and the beta-bromostyrene compound 2 can be obtained in one step. The method is capable of solving thetechnical problem that in the traditional synthesis method, conversion into alkenyl boron, alkenyl silicon and other intermediates under the catalysis of noble metals and then further halogenation are needed; the defects of expensive reaction reagent, high catalytic cost, complex operation, incapability of large-scale preparation and the like in the traditional preparation method are avoided; byadopting the method, a series of beta-bromostyrene compounds can be obtained, and the method has a potential application prospect.
- -
-
Paragraph 0034-0036
(2020/02/06)
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- Facile Synthesis of β-Bromostyrenes by Direct Bromination of Styrenes with N -Bromosuccinimide and Sodium Persulfate
-
A new, direct, efficient, and transition-metal-free method is reported for the synthesis of β-bromostyrenes from styrenes by using N -bromosuccinimide as the brominating reagent and sodium persulfate (Na 2S 2O 8) as the oxidant. This convenient and concise reaction is practical, operationally simple, and can be adapted for large-scale syntheses.
- Chen, Xuenian,Gao, Yan,Jing, Yi,Ma, Yan-Na,Zhao, Qianyi
-
supporting information
(2020/09/09)
-
- Electrochemical intramolecular C-H/N-H functionalization for the synthesis of isoxazolidine-fused isoquinolin-1(2: H)-ones
-
A general and practical protocol for the construction of isoxazolidine-fused isoquinolin-1(2H)-ones has been described by electrochemical-oxidation-induced intramolecular annulation via amidyl radicals. In an undivided cell, isoquinolinones could be easily generated from various available amides bearing CONHOR groups under metal-free, additive-free and external oxidant-free conditions. Moreover, this transformation proceeded smoothly by using cheap 95% ethanol as the green solvent and could be extended to the gram scale.
- Zhang, Lin-Bao,Geng, Rui-Sen,Wang, Zi-Chen,Ren, Guang-Yi,Wen, Li-Rong,Li, Ming
-
supporting information
p. 16 - 21
(2020/01/13)
-
- Transition-Metal-Free α-Vinylation of Enolizable Ketones with β-Bromostyrenes
-
An α-vinylation of enolizable ketones has been developed by using β-bromostyrenes and a KOtBu/NMP system. β,γ-Unsaturated ketones of E configuration were obtained in excellent yield and selectivity. Further synthetic possibilities are highlighted by one-pot functionalization via trapping of intermediate dienolates with alkyl, allyl, benzyl, and propargyl halides to generate quaternary centers. The reported transformation is believed to involve phenylacetylene and propargylic alcohol derivatives.
- Zaid, Yassir,Mboyi, Clève Dionel,Drapeau, Martin Pichette,Radal, Léa,Chahdi, Fouad Ouazzani,Rodi, Youssef Kandri,Ollevier, Thierry,Taillefer, Marc
-
supporting information
p. 1564 - 1568
(2019/03/11)
-
- Transition-metal-free decarboxylative bromination of aromatic carboxylic acids
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Methods for the conversion of aliphatic acids to alkyl halides have progressed significantly over the past century, however, the analogous decarboxylative bromination of aromatic acids has remained a longstanding challenge. The development of efficient methods for the synthesis of aryl bromides is of great importance as they are versatile reagents in synthesis and are present in many functional molecules. Herein we report a transition metal-free decarboxylative bromination of aromatic acids. The reaction is applicable to many electron-rich aromatic and heteroaromatic acids which have previously proved poor substrates for Hunsdiecker-type reactions. In addition, our preliminary mechanistic study suggests that radical intermediates are not involved in this reaction, which is in contrast to classical Hunsdiecker-type reactivity. Overall, the process demonstrates a useful method for producing valuable reagents from inexpensive and abundant starting materials.
- Quibell, Jacob M.,Perry, Gregory J. P.,Cannas, Diego M.,Larrosa, Igor
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p. 3860 - 3865
(2018/04/26)
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- Palladium-Catalyzed Domino Reaction for Stereoselective Synthesis of Multisubstituted Olefins: Construction of Blue Luminogens
-
The first Pd-catalyzed multicomponent reaction of aryl iodides, alkenyl bromides, and strained alkenes has been developed, which allowed us to synthesize a variety of multisubsituted olefins in yields of 45-96% with excellent stereoselectivity. The configuration of the product was controlled by the configuration of the alkenyl bromides. Moreover, this practical methodology employing readily available substrates was found to be tolerant to a wide range of functional groups. Fifty six examples of highly stereoselective tri- or tetrasubstituted olefins have been successfully synthesized via this methodology. Most of the synthesized tetrasubstituted olefins are good aggregation-induced emission (AIE) luminogens.
- Hao, Tao-Tao,Liang, Hao-Ran,Ou-Yang, Ying-Han,Yin, Chang-Zhen,Zheng, Xue-Li,Yuan, Mao-Lin,Li, Rui-Xiang,Fu, Hai-Yan,Chen, Hua
-
p. 4441 - 4454
(2018/04/26)
-
- TsNBr2 promoted decarboxylative bromination of α,β-unsaturated carboxylic acids
-
A rapid process for decarboxylative bromination of α,β-unsaturated carboxylic acids have been developed using N,N-dibromo-p-toluenesulfonamide (TsNBr2). Treatment of cinnamic acids with TsNBr2 in presence of potassium carbonate in acetonitrile produces corresponding β-bromostyrenes at room temperature. Exclusive formation of (E)-β-bromostyrenes was observed in a stereoselective manner within a very short period of time (5–15 min). This method was further extended for obtaining 1-bromoalkynes from corresponding propiolic acids. Instantaneous formation of bromoalkynes was observed when the reaction was carried out in presence of DBU as a base in acetonitrile at room temperature. A wide variety of cinnamic acids and propiolic acids could be converted to corresponding β-bromostyrenes and 1-bromoalkynes respectively under mild reaction condition with high to excellent yield.
- Hazarika, Debojit,Phukan, Prodeep
-
supporting information
p. 4593 - 4596
(2018/11/23)
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- A stereoselective synthesis of (E)- or (Z)-β-arylvinyl halides via a borylative coupling/halodeborylation protocol
-
A new stereoselective method for the synthesis of (E)-β-arylvinyl iodides and (E)- or (Z)-β-arylvinyl bromides from styrenes and vinyl boronates on the basis of a one-pot procedure via borylative coupling/halodeborylation is reported. Depending on the halogenating agent as well as the mode of the halodeborylation reaction, (E) or (Z) isomers are selectively formed.
- Szyling, Jakub,Franczyk, Adrian,Pawlu?, Piotr,Marciniec, Bogdan,Walkowiak, J?drzej
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p. 3207 - 3215
(2017/04/21)
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- Nickel-Catalyzed Reductive Cross-Coupling of Vinyl Bromides with Unactivated Alkyl Halides
-
The use of pyridine as the sole ligand for the reductive vinylation of unactivated secondary alkyl halides under Ni-catalyzed conditions has been developed. Both alkyl- and aryl-substituted vinyl bromides are suitable, in which alkyl-decorated α-alkenyl bromides resulted in the α-products in good results.
- Gu, Jun,Qiu, Canbin,Lu, Wenbin,Qian, Qun,Lin, Kunhua,Gong, Hegui
-
supporting information
p. 1867 - 1873
(2017/04/06)
-
- Stereoselective Synthesis of Vinyl Iodides through Copper(I)-Catalyzed Finkelstein-Type Halide-Exchange Reaction
-
An efficient method for the stereoselective synthesis of vinyl iodides is described. The reactions of vinyl bromides with potassium iodide proceed smoothly in the presence of a copper catalyst under mild reaction conditions to produce the corresponding vinyl iodides stereospecifically and in satisfactory to excellent yields.
- Feng, Xiujuan,Zhang, Haixia,Lu, Wenbo,Yamamoto, Yoshinori,Almansour, Abdulrahman I.,Arumugam, Natarajan,Kumar, Raju Suresh,Bao, Ming
-
supporting information
p. 2727 - 2732
(2017/06/13)
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- Decarboxylative bromination of α,β-unsaturated carboxylic acids via an anodic oxidation
-
A novel bromination of α,β-unsaturated carboxylic acids was developed via a decarboxylation by virtue of a direct anodic electro-oxidation. In this method, ammonium bromide was employed as a bromine source and the reaction features transition-metal-free, short time, and no additional supporting electrolyte.
- Bi, Mei-Xiang,Qian, Peng,Wang, Yu-Kang,Zha, Zheng-Gen,Wang, Zhi-Yong
-
p. 1159 - 1162
(2017/06/19)
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- Tellurium-promoted stereoselective hydrodebromination of 1,1-dibromoalkenes: Synthesis of (: E)-bromoalkenes
-
We describe herein an efficient and simple method for the stereoselective hydrodebromination of 1,1-dibromoalkenes by using a catalytic amount of the nucleophilic species of tellurium, generated in situ by the reaction of elemental tellurium with NaBH4. By this methodology, (E)-bromoalkenes were obtained in moderate to excellent yields under mild reaction conditions, without the use of transition metals or base. Furthermore, a high stereoselectivity for the (E)-isomer was observed when 1,1-dibromoarylalkenes were used, thus indicating a promising alternative for future applications in organic synthesis.
- Perin, Gelson,Barcellos, Angelita M.,Peglow, Thiago J.,Nobre, Patrick C.,Cargnelutti, Roberta,Lenard?o, Eder J.,Marini, Francesca,Santi, Claudio
-
p. 103657 - 103661
(2016/11/13)
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- Ni-catalyzed reductive coupling of α-halocarbonyl derivatives with vinyl bromides
-
This work describes the vinylation of α-halo carbonyl compounds with vinyl bromides under Ni-catalyzed reductive coupling conditions. While aryl-conjugated vinyl bromides entail pyridine as the sole labile ligand, the alkyl-substituted vinyl bromides require both bipyridine and pyridine as the co-ligands.
- Qiu, Canbin,Yao, Ken,Zhang, Xinghua,Gong, Hegui
-
p. 11332 - 11335
(2016/12/18)
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- Preparation of Vinyl Arenes by Nickel-Catalyzed Reductive Coupling of Aryl Halides with Vinyl Bromides
-
This work emphasizes the synthesis of substituted vinyl arenes by reductive coupling of aryl halides with vinyl bromides under mild and easy-to-operate nickel-catalyzed reaction conditions. A broad range of aryl halides, including heteroaromatics, and vinyl bromides were employed to yielding products in moderate to excellent yields with high functional-group tolerance. The nickel-catalytic system displays good chemoselectivity between the two C(sp2)-halide coupling partners, thus demonstrating a mechanistic pathway distinct from other stepwise protocols.
- Liu, Jiandong,Ren, Qinghua,Zhang, Xinghua,Gong, Hegui
-
p. 15544 - 15548
(2016/12/09)
-
- Nucleophile-selective cross-coupling reactions with vinyl and alkynyl bromides on a dinucleophilic aromatic substrate
-
A nucleophile-selective cross-coupling reaction on an aromatic compound bearing two metal groups, Bpin and SnMe3, has been developed. Previously, only aryl bromides and iodides could be used as electrophilic components, but in this work, the scope could be extended to vinyl and alkynyl bromides as electrophiles. This means that the roles typical in Sonogashira couplings or Heck reactions of the aromatic ring as the dielectrophile coupling to vinyl and alkynyl metal species are reversed, which presents a new tool for organic synthesis. The first nucleophilic site to react is the stannyl group, and subsequently, a Suzuki-Miyaura cross-coupling reaction can take place on the same molecule.
- He, Lu-Ying,Schulz-Senft, Mathias,Thiedemann, Birk,Linshoeft, Julian,Gates, Paul J.,Staubitz, Anne
-
supporting information
p. 2498 - 2502
(2015/04/22)
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- H-β-zeolite catalyzed synthesis of β-bromostyrenes from styrene bromohydrins
-
Synthesis of β-bromostyrenes from styrene bromohydrins using H-β-zeolite as catalyst under moderate conditions is reported. The catalyst could be regenerated and reused up to three consecutive cycles.
- Pappula, Venkatanarayana,Donthiri, Ramachandra Reddy,Darapaneni, Chandra Mohan,Subbarayappa, Adimurthy
-
supporting information
p. 1793 - 1795
(2014/03/21)
-
- Transition-metal free synthesis of diaryl vinyl selenides: A simple synthetic approach with high selectivity
-
A simple, highly efficient synthetic protocol is developed for the synthesis of unsymmetrical diaryl vinyl selenides from diaryldiselenide and β-bromo styrene under transition-metal free conditions in N,N′-dimethyl propylene urea and 130 °C to afford high yields and excellent selectivities. This method provides a new strategy to fabricate a wide variety of important substituted molecular skeletons and an alternative to conventionally used metal salts, additives, and ligands.
- Mohan, Balaji,Hwang, Sori,Woo, Hyunje,Park, Kang Hyun
-
supporting information
p. 2699 - 2702
(2014/04/17)
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- Nickel(II)-magnesium-catalyzed cross-coupling of 1,1-dibromo-1-alkenes with diphenylphosphine oxide: One-pot synthesis of (E)-1-alkenylphosphine oxides or bisphosphine oxides
-
A novel nickel(II)-magnesium-mediated cross-coupling of diphenylphosphine oxide with a variety of 1,1-dibromo-1-alkenes has been developed, which provides a powerful and general methodology for the stereoselective synthesis of various (E)-1-alkenylphosphine oxides or bisphosphine oxides, with operational simplicity of the procedure, good to high yields and broad substrate applicability. Mechanistic studies reveal that the reaction might involve a Hirao reduction, cross-coupling and Michael addition. Copyright
- Liu, Liu,Wang, Yulei,Zeng, Zhiping,Xu, Pengxiang,Gao, Yuxing,Yin, Yingwu,Zhao, Yufen
-
supporting information
p. 659 - 666
(2013/04/10)
-
- A green hunsdiecker reaction of cinnamic acids
-
Tribromo- and trichloroisocyanuric acids react with cinnamic acids in NaOH/H2O/Et2O at room temperature to produce (E)-2-halostyrenes regioselectively in 25-95percent yield. Mechanism studies using Hammett correlations and DFT (density functional theory) calculations have shown that this reaction has as rate determining step the electrophilic addition of chlorine atom to the double bond.
- Sodre?, Leonardo R.,Esteves, Pierre M.,De Mattos, Marcio C. S.
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p. 212 - 218
(2013/05/08)
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- Halodeboronation of organotrifluoroborates using tetrabutylammonium tribromide or cesium triiodide
-
Halodeboronation of organotrifluoroborates using commercially available tetrabutylammonium tribromide (TBATB) or cesium triiodide in aqueous medium is reported. The mild, transition metal-free method has proven to be tolerant of a wide range of functional groups. High regio- and chemoselectivity are observed. Two synthetic routes to (Z)-dibromoalkenes from alkynes, through stereodefined (Z)-2-bromoalkenyltrifluoroborates and (Z)-1,2-bis(boryl) alkenyltrifluoroborates, have been developed using the TBATB mediated bromodeboronation as the key step.
- Yao, Min-Liang,Kabalka, George W.,Blevins, David W.,Reddy, Marepally Srinivasa,Yong, Li
-
experimental part
p. 3738 - 3743
(2012/06/30)
-
- Microwave-assisted Pd/Cu-catalyzed C-8 direct alkenylation of purines and related azoles: An alternative access to 6,8,9-trisubstituted purines
-
An efficient microwave-assisted palladium/copper comediated C-8 direct alkenylation of purines with styryl bromides has been developed. The method is regioselective, functional group tolerant, rapid, and compatible with other related azoles. Combined with
- Vabre, Roxane,Chevot, Franciane,Legraverend, Michel,Piguel, Sandrine
-
experimental part
p. 9542 - 9547
(2011/12/22)
-
- Synthesis of 2- and 2,3-substituted Pyrazolo[1,5- a ]pyridines: Scope and mechanistic considerations of a domino direct alkynylation and cyclization of n -iminopyridinium ylides using alkenyl bromides, alkenyl iodides, and alkynes
-
Direct functionalization and tandem processes have both received considerable recent interest due to their cost and time efficiency. Herein we report the synthesis of difficult to obtain 2-substituted pyrazolo[1,5-a] pyridines through a tandem palladium-catalyzed/silver-mediated elimination/direct functionalization/cyclization reaction involving N-benzoyliminopyridinium ylides. As such, these biologically important molecules are prepared in an efficient, high-yielding manner, only requiring a two-step sequence from pyridine. Aryl-substituted alkenyl bromides and iodides are effective ylide coupling partners. Mechanistic studies led to the use of terminal alkynes, which extended the scope of the reaction to include alkyl substitution on the unsaturated reactive site. The optimization, scope, and mechanistic considerations of the process are discussed.
- Mousseau, James J.,Bull, James A.,Ladd, Carolyn L.,Fortier, Angelique,Sustac Roman, Daniela,Charette, Andre B.
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experimental part
p. 8243 - 8261
(2012/01/03)
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- Chemoselective bromodeboronation of organotrifluoroborates using tetrabutylammonium tribromide: Application in (Z)-dibromoalkene syntheses
-
(Chemical Equation Presented) Tetrabutylammonlum trlbromlde (TBATB) has been found to be a unique bromodeboronatlon reagent for organotrlf luoroborates. When compared to previously reported bromodeboronatlon methods, the mild and metal-free reaction conditions tolerate a wider range of functional groups. High reglo- and chemoselectlvlty are observed In the presence of both unsaturated carbon-carbon bonds and aldehyde functional groups. An efficient synthetic route to (Z)-dlbromoalkenes from terminal alkynes has been developed using the TBATB-medlated bromodeboronatlon as a key step.
- Yao, Min-Liang,Reddy, Marepally Srinivasa,Li, Yong,Walfish, Ingrid,Blevins, David W.,Kabalka, George W.
-
supporting information; experimental part
p. 700 - 703
(2010/04/02)
-
- Copper oxide nanoparticles catalyzed vinylation of imidazoles with vinyl halides under ligand-free conditions
-
Recyclable copper oxide nanoparticles catalyzed most efficient and straightforward protocol for the vinylation of imidazoles with vinyl halides under ligand-free conditions. Utilizing this protocol various imidazoles were cross-coupled with different substituted vinyl halides to get the corresponding products in excellent yields with the retention configuration.
- Prakash Reddy,Vijay Kumar,Rama Rao
-
supporting information; experimental part
p. 3181 - 3185
(2010/08/05)
-
- Transfer of alk-1-enyl group from boron to tin: A highly stereoselective synthesis of (E)-alk-1-enyltributylstannanes
-
Treatment of (E)-alk-1-enyldicyclohexylboranes with tributyltin methoxide in the presence of galvinoxyl (1 mol%) at room temperature results in transfer of the alk-1-enyl group from boron to tin to give (E)-alk-1- enyltributylstannanes in a highly stereoselective fashion. Subsequent halodestannylation of (E)-alk-1-enyltributylstannanes is allowed to proceed in a one-pot manner to produce the corresponding (E)-1-iodoalk-1-enes and (E)-1-bromoalk-1-enes in good to high yields, respectively. Georg Thieme Verlag Stuttgart.
- Hoshi, Masayuki,Hayatsu, Takaki,Okimoto, Mitsuhiro,Kodama, Satoshi
-
scheme or table
p. 2945 - 2948
(2010/02/28)
-
- Recyclable nano copper oxide catalyzed stereoselective synthesis of vinyl sulfides under ligand-free conditions
-
A simple and efficient protocol for the cross-coupling of vinyl halides with thiols catalyzed by recyclable CuO nanoparticles under ligand-free conditions is reported. This methodology results in the synthesis of a variety of vinyl sulfides in excellent y
- Reddy, Vutukuri Prakash,Swapna, Kokkirala,Kumar, Akkilagunta Vijay,Rao, Kakulapati Rama
-
experimental part
p. 2783 - 2788
(2010/03/03)
-
- Stereoselective direct copper-catalyzed alkenylation of oxazoles with bromoalkenes
-
(Chemical Equation Presented) A copper-catalyzed direct alkenylation of oxazoles with bromoalkenes has been developed. The method is both regio- and stereoselective and tolerates a variety of functional groups. A wide range of 2-E-vinyl-substituted oxazoles were obtained in high yields including the highly fluorescent alkaloid annuloline.
- Besselievre, Francois,Piguel, Sandrine,Mahuteau-Betzer, Florence,Grierson, David S.
-
supporting information; experimental part
p. 4029 - 4032
(2009/06/18)
-
- Convenient one-pot synthesis of (E)-β-aryl vinyl halides from benzyl bromides and dihalomethanes
-
(Chemical Equation Presented) (E)-β-Aryl vinyl iodides are synthesized in high yield with excellent stereoselectivity from benzyl bromides by a one-pot homologation/ stereoselective elimination procedure. Convenient conditions involving the anion of diiodomethane and an excess of base provide complete consumption of the benzyl bromide and elimination from a diiodoalkane intermediate. Similar conditions provide (E)-β-aryl vinyl chlorides and bromides by employing the anions of ICH2CI or CH2Br 2. The functional group tolerance and facile purification allows rapid access to a wide range of functionalized vinyl halides.
- Bull, James A.,Mousseau, James J.,Charette, Andre B.
-
supporting information; experimental part
p. 5484 - 5488
(2009/06/06)
-
- Palladium-catalyzed cross-coupling between vinyl halides and tert-butyl carbazate: First general synthesis of the unusual N-Boc-N-alkenylhydrazines
-
(Chemical Equation Presented) N-Boc-N-alkenylhydrazines, an almost unknown type of compounds, have been prepared with high to moderate yields via palladium-catalyzed cross-coupling between alkenyl halides and fert-butyl carbazate. The present methodology represents the first general way to access this highly functionalized and unusual type of hydrazines.
- Barluenga, Jose,Moriel, Patricia,Aznar, Fernando,Valdes, Carlos
-
p. 275 - 278
(2007/10/03)
-
- A novel system for decarboxylative bromination
-
A simple and mild method for decarboxylative bromination of α,β-unsaturated carboxylic acids has been developed using diphosphorus tetraiodide in combination with tetraethylammonium bromide (TEAB) at room temperature. High yields of the corresponding bromoalkenes were obtained.
- Telvekar, Vikas N.,Chettiar, Somsundaram N.
-
p. 4529 - 4532
(2008/02/03)
-
- Stereoselective synthesis of (E)-β-arylvinyl bromides by microwave-induced reaction of anti-3-aryl-2,3-dibromopropanoic acids using an AgOAc-AcOH system
-
(E)-β-Arylvinyl bromides were stereoselectively prepared in high yields by microwave irradiation of the corresponding anti-3-aryl-2,3- dibromopropanoic acids in AcOH in the presence of AgOAc for 0.5-3.0 min. (E)-β-Arylvinyl bromides were stereoselectively prepared in high yields by microwave irradiation of the corresponding anti-3-aryl-2,3-dibromo-propanoic acids in AcOH in the presence of AgOAc for 0.5-3.0 min.
- Kuang, Chunxiang,Senboku, Hisanori,Tokuda, Masao
-
p. 637 - 642
(2007/10/03)
-
- Stereoselective synthesis of (E)-β-arylvinyl bromides by microwave-induced Hunsdiecker-type reaction
-
(E)-β-Arylvinyl bromides were readily prepared in a short reaction time (1-2 min) by microwave irradiation of the corresponding 3-arylpropenoic acids in the presence of N-bromosuccinimide and a catalytic amount of lithium acetate. Furthermore, two facile strategies for the efficient synthesis of (E)-β-bromo-4-arylethynylstyrene and (E)-β-bromo-4-arylstyrene have been developed by respectively combining Sonogashira and Suzuki coupling reaction with Hunsdiecker-type reaction. Formation of cis-α-bromo-β- lactone by microwave irradiation of cis-cinnamic acid with NBS provides a useful support for the mechanistic study of the present halodecarboxylation reaction. Georg Thieme Verlag Stuttgart.
- Kuang, Chunxiang,Yang, Qing,Senboku, Hisanori,Tokuda, Masao
-
p. 1319 - 1325
(2007/10/03)
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- Synthesis of vinyl bromides from the reaction of α, β-unsaturated carboxylic acids with ionic liquid [bmim][Br 3]/[bmim]Br
-
Reaction of aryl α, β-unsaturated carboxylic acids with ionic liquid [bmim][Br3]/[bmim]Br affords vinyl bromides in a short reaction time and in good to excellent yields.
- Wang, Congna,Bao, Weiliang,Zhang, Xiaoyin
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p. 617 - 619
(2007/10/03)
-
- Mild and efficient method for decarboxylative bromination of α,β-unsaturated carboxylic acids with Dess-Martin periodinane
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A simple and mild method for decarboxylative bromination of α,β-unsaturated carboxylic acids has been developed using Dess-Martin Periodinane (DMP) in combination with tetraethylammonium bromide (TEAB) at room temperature. High yields of the corresponding bromoalkenes were obtained. Georg Thieme Verlag Stuttgart.
- Telvekar, Vikas N.,Arote, Nitin D.,Herlekar, Omkar P.
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p. 2495 - 2497
(2007/10/03)
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- A new and facile method for stereoselective synthesis of (E)-styryl bromides by the reduction of 1,1-dibromoalkenes using LiAlH4-EtOAc (1:1)
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A facile method for stereoselective synthesis of (E)-styryl bromides by the reduction of 1,1-dibromoalkenes using LiAlH4-EtOAc (1:1) is described. We believe that the present procedure is a good alternative to the Tokuda's microwave method with good stereoselectivity.
- Horibe, Hideo,Kondo, Kazuhiro,Okuno, Hiroaki,Aoyama, Toyohiko
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p. 986 - 988
(2007/10/03)
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- π-extended conjugate phenylacetylenes. Synthesis of 4-[(E) and (Z)-2-(4-ethenylphenyl)ethenyl]pyridine. Dimerization, quaternation and formation of charge-transfer complexes
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The conjugate (E)- and (Z)-(4′-pyridylethenyl)-4-phenylethyne (E-4 and Z-4) has been satisfactorily prepared by two different routes: (a) by dehydrohalogenation of 4′-pyridylethenyl-4-phenyl-β-chloroethene; (b) by the Wittig reaction between p-(iodobenzyl)(triphenyl)phosphine ylide and 4-pyridinecarboxaldehyde, E/Z isomer separation, and cross-coupling with 2-methyl-but-3-yn-2-ol followed the propanone elimination. The Glaser oxidative dimerization of (Z)-4 yields (Z,Z)-1,4-di[(4′-pyridylethenyl)-4-phenyl]-buta-1,3-diyne in good yield, (Z,Z)-5. (E,E)-5 was obtained by phase transfer oxidative dimerisation of (E)-4 in presence of their N-methyl salt (E)-10. Mono- and di-N-methylated salts of conjugate (E,E)-5 and (Z,Z)-5, were obtained by quaternation with iodomethane. The (Z,Z)-5 di-N-methylated salt forms charge-transfer complexes with TCNE, TCNQ and TMPD.
- Rodríguez, J. Gonzalo,Martín-Villamil, Rosa,Lafuente, Antonio
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p. 1021 - 1032
(2007/10/03)
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- Facile and stereoselective synthesis of (E)-vinyl bromides by microwave-induced reaction of 1,1-dibromoalkenes using a diethyl phosphonate/EtONa/EtOH system
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(E)-Vinyl bromides were readily prepared from 1,1-dibromoalkenes by microwave irradiation within 1 min using a diethyl phosphonate/EtONa/EtOH system. This method utilizes cheap and environmentally friendly reagents, requires only a short reaction time, and gives (E)-vinyl bromides in high stereoselectivities and high yields.
- Kuang, Chunxiang,Senboku, Hisanori,Tokuda, Masao
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p. 1491 - 1496
(2007/10/03)
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- Catalytic Hunsdiecker reaction of α,β-unsaturated carboxylic acids: How efficient is the catalyst?
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UV-vis spectrophotometry is utilized to measure the relative efficiency of lithium acetate, tetrabutylammonium trifluoroacetate, and triethylamine as catalysts for the conversion of 4-methoxycinnamic acid to 4-methoxy-β-bromostyrene. In acetonitrile - water as solvent, the efficiency order is lithium acetate > triethylamine > tetrabutylammonium trifluoroacetate. For triethylamine as catalyst, solvent-dependent order is acetonitrile - water > dichloromethane > acetonitrile. Using triethylamine as catalyst (5-20 mol %), cinnamic acids, and propiolic acids are converted to corresponding β-bromostyrenes and 1-halo-1-alkynes in 60-98% isolated yields within 1-5 min.
- Prakash Das, Jaya,Roy, Sujit
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p. 7861 - 7864
(2007/10/03)
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- Halodecarboxylation of a,β-unsaturated carboxylic acids bearing aryl and styrenyl group at β-carbon with Oxone and sodium halide
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Reaction of α,β-unsaturated carboxylic acid bearing aryl and styrenyl group at β-carbon with Oxone and sodium halide in aqueous acetonitrile afforded the corresponding haloalkenes.
- You,Lee
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p. 105 - 107
(2007/10/03)
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- Catalytic Hunsdiecker reaction and one-pot catalytic Hunsdiecker-Heck strategy: Synthesis of α,β-unsaturated aromatic halides, α- (dihalomethyl)benzenemethanols, 5-aryl-2,4-pentadienoic acids, dienoates and dienamides
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The reaction of α,β-unsaturated aromatic (or heteroaromatic) carboxylic acids with N-halosuccinimides (1 equiv.) and catalytic tetrabutylammonium trifluoroacetate (0.2 equiv.) in dichloroethane results in facile halodecarboxylation affording the corresponding (E)-halides in good to excellent yields. A similar reaction, but with 2 equiv. of N-halosuccinimides in acetonitrile-water (1:1 v/v) results in the exclusive formation of the corresponding α-(dihalomethyl)benzenemethanols. Furthermore, a one-pot strategy has been developed combining catalytic Hunsdiecker reaction (using tetrabutylammonium trifluoroacetate in dichloroethane) and Heck coupling (using palladium acetate/triethylamine/triphenylantimony/dichloroethane) for the synthesis of 5-aryl-2,4-pentadienoic acids, esters and amides in moderate to good yields. The natural product piperine and pipergualamine has been synthesized via the above route. Mechanistic and theoretical studies (via AM1 calculations) provide a useful insight into the mechanism of the present halodecarboxylation reaction, suggesting an ionic pathway involving the attack of the halogenium ion across the carbon-carbon double bond, triggering the elimination of carbon dioxide. (C) 2000 Elsevier Science Ltd.
- Naskar, Dinabandhu,Roy, Sujit
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p. 1369 - 1377
(2007/10/03)
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- A facile regio- and stereocontrolled synthesis of (E)-vinylphosphonates via cross coupling of (E)-vinyl iodides with dialkyl phosphites
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(E)-Vinylphosphonates were conveniently obtained under mild condition via the cross coupling of the corresponding (E)-vinyl iodides, which were obtained from the reaction of vinylzirconocenes with iodine, with dialkyl phosphites.
- Zhong, Ping,Xiong, Zhi Xing,Huang, Xian
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p. 273 - 278
(2007/10/03)
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- Stereoselective synthesis of (E)-β-arylvinyl halides by microwave-induced Hunsdiecker reaction
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(E)-β-Arylvinyl halides were prepared in high yields in a short reaction (1-2 min) by microwave irradiation of the corresponding 3-arylpropenoic acids in the presence of N-halosuccinimide and catalytic LiOAc.
- Kuang,Senboku,Tokuda
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p. 1439 - 1442
(2007/10/03)
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- Halodecarboxylation of α,β-acetylenic and α,β-ethylenic acids
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Reaction of bis(collidine)iodine(I) (or bromine (I)) hexafluorophosphate with acetylenic acids led to the corresponding iodo(or bromo)acetylenes in high yields. This halodecarboxylation reaction was also observed with acrylic acids substituted in position 3 by an aryl group or an heteroatom.
- Homsi, Fadi,Rousseau, Gerard
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p. 1495 - 1498
(2007/10/03)
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- Stereoselective hydrogenolysis of 1,1-dibromo-1-alkenes and stereospecific synthesis of conjugated (Z)-alkenyl compounds
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The Pd-catalyzed hydrogenolysis of 1,1-dibromoalkenes with Bu3SnH occurs at room temperature stereoselectively to give (Z)-1-bromo-1-alkenes. We sought to determine the optimal reaction conditions and illustrate the scope of this method with 32 dibromoalkenes including alkenyl- and alkynyl- conjugated 1,1-dibromo-1-alkenes 7a-h and 2,2-disubstituted 1,1-dibromo-1- alkenes 9af. Triphenylphosphine was the best ligand for the Pd-catalyzed hydrogenolysis. A wide range of solvents can be used for this reaction excluding EtOH, AcOH, and CHCl3. However, the reaction proceeds even in these solvents with the addition of a cosolvent or radical scavenger. The reaction of 1,1-diiodo-1-alkene (3) gave a mixture of (Z)-1-iodo-1-alkene (4), (Z)-1-tributylstannyl-1-alkene (5), and a terminal alkene 6, while that of 1,1-dichloroalkene did not occur. This selectivity can be explained by the stereoselective insertion of Pd(0) to a trans bromine-alkenyl carbon bond, successive transmetalation with Bu3SnH, and reductive elimination. The Suzuki and Sonogashira couplings of the resulting (Z)-1-bromo-1-alkenes with alkenyl(dialkoxy)borane and terminal alkyne occurred to give conjugated polyenes and enynes stereospecifically. The Pd-catalyzed hydrogenolysis of 1,1-dibromo-1-alkene and successive cross-coupling can be carried out either in a stepwise manner or in one-pot under the same Pd catalysis. These two processes should be useful for the synthesis of geometrically pure polyene and enyne with a Z-alkenyl unit.
- Uenishi, Jun'ichi,Kawahama, Reiko,Yonemitsu, Osamu,Tsuji, Jiro
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p. 8965 - 8975
(2007/10/03)
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- Is metal necessary in the Hunsdiecker-Borodin reaction?
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The tetrabutylammonium trifluoroacetate (TBATFA) catalyzed conversion of α,β-unsaturated carboxylic acids to the corresponding halides with N-halosuccinimides in dichloroethane is reported as the first example of a metal-free catalytic version of the title reaction. The methodology was further employed for a facile synthesis of piperine.
- Naskar, Dinabandhu,Chowdhury, Shantanu,Roy, Sujit
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p. 699 - 702
(2007/10/03)
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