- Dibrominated addition and substitution of alkenes catalyzed by Mn2(CO)10
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A practical method for the dibromination of alkenes without using molecular bromine is consistently appealing in organic synthesis. Herein, we report Mn-catalyzed dibrominated addition and substitution of alkenes only with N-bromosuccinimide, producing a variety of synthetically valuable dibrominated compounds in moderate to high yields. This journal is
- Chan, Albert S. C.,Jiang, Yi,Meng, Shanshui,Song, Xianheng,Zhang, Hong,Zou, Yong
-
supporting information
p. 13385 - 13388
(2021/12/17)
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- Dihalogenation of Alkenes Using Combinations of N-Halosuccinimides and Alkali Metal Halides
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A simple, efficient and eco-friendly method for the vicinal dihalogenation of alkenes is described. The reaction is performed with a combination of a N-halosuccinimide and an alkali metal halide using environmentally benign solvents such as acetic acid an
- Barrio, Pablo,García-Pedrero, Olaya,López-Matanza, Pablo,Rodríguez, Félix,Rubio-Presa, Rubén
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supporting information
p. 4762 - 4766
(2021/09/10)
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- Photoredox-catalyzed synthesis of N-unsubstituted enaminosulfones from vinyl azides and sulfinates
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A metal-free visible light photoredox-catalyzed synthesis of N-unsubstituted enaminosulfones from vinyl azides and sodium sulfinates in moderate to high yields is described. The reaction proceeds in ethanol and uses eosin Y as a readily available photocatalyst in combination with nitrobenzene as an electron shuttle. Taking into account the number of steps involved (generation of the sulfonyl radical, its addition to the double bond, elimination of molecular nitrogen with formation of an iminyl radical, followed by its reduction and protonation) as well as the number of redox-active reaction partners involved, the selectivity of the process is quite impressive.
- Mulina, Olga M.,Ilovaisky, Alexey I.,Opatz, Till,Terent'ev, Alexander O.
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supporting information
(2021/01/11)
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- Electrosynthesis of N-unsubstituted enaminosulfones from vinyl azides and sodium sulfinates mediated by NH4I
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A wide range of N-unsubstituted enaminosulfones were obtained via electrochemical sulfonylation of vinyl azides with sulfonyl radicals generated from sodium sulfinates. The discovery of N-unsubstituted enaminosulfones synthesis is based on a unique ability of the azido group to eliminate the N2 molecule. The process is performed under constant current conditions in an experimentally convenient undivided electrochemical cell equipped with a graphite anode and a stainless steel cathode applying NH4I both as the redox catalyst and the supporting electrolyte.
- Mulina, Olga M.,Doronin, Mikhail M.,Terent'ev, Alexander O.
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supporting information
(2021/10/16)
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- A General Method for the Dibromination of Vicinal sp3C-H Bonds Exploiting Weak Solvent-Substrate Noncovalent Interactions
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A general procedure of 1,2-dibromination of vicinal sp3 C-H bonds of arylethanes using N-bromosuccinimide as the bromide reagent without an external initiator has been established. The modulation of the strength of the intermolecular noncovalent interactions between the solvent and arylethane ethanes, quantitatively evaluated via quantum chemical calculations, allows us to circumvent the fact that arylethane ethane cannot be dibrominated through traditional methods. The mechanism was explored by both experiments and quantum chemical calculations, revealing a radical chain with HAA process.
- Qi, Zaojuan,Li, Weihe,Niu, Yanning,Benassi, Enrico,Qian, Bo
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supporting information
p. 2399 - 2404
(2021/03/03)
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- The intramolecular reaction of acetophenoneN-tosylhydrazone and vinyl: Br?nsted acid-promoted cationic cyclization toward polysubstituted indenes
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In the presence of TsNHNH2, a Br?nsted acid-promoted intramolecular cyclization ofo-(1-arylvinyl) acetophenone derivatives was developed, leading to polysubstituted indenes with complexity and diversity in moderate to excellent yields. In sharp contrast with either the radical or carbene involved cyclization of aldehydicN-tosylhydrazone with vinyl, a cationic cyclization pathway was involved, whereN-tosylhydrazone served as an electrophile and alkylation reagent during this transformation.
- Wang, Zhixin,Li, Yang,Chen, Fan,Qian, Peng-Cheng,Cheng, Jiang
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supporting information
p. 1810 - 1813
(2021/02/27)
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- Electrochemical Synthesis of O-Phthalimide Oximes from α-Azido Styrenes via Radical Sequence: Generation, Addition and Recombination of Imide-N-Oxyl and Iminyl Radicals with C?O/N?O Bonds Formation
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Electrochemically induced radical-initiated reaction of vinyl azides with N-hydroxyphthalimide resulting O-phthalimide oximes with challenging for organic chemistry N?O-N fragment has been discovered. The developed approach introduces in synthesis electrochemically generated O-centered imide-N-oxyl radicals as the coupling components. Sequential formation of C?O and N?O bonds was achieved via generation and selective addition of imide-N-oxyl radicals, followed by recombination with iminyl radicals. A wide range of O-phthalimide oximes was obtained with the yields up to 84percent. (Figure presented.).
- Paveliev, Stanislav A.,Churakov, Artem I.,Alimkhanova, Liliya S.,Segida, Oleg O.,Nikishin, Gennady I.,Terent'ev, Alexander O.
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supporting information
p. 3864 - 3871
(2020/07/30)
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- Zn-ProPhenol Catalyzed Enantioselective Mannich Reaction of 2 H-Azirines with Alkynyl Ketones
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The enantioselective Mannich reaction of 2H-azirines with alkynyl ketones is achieved under Zn-ProPhenol catalysis, delivering various aziridines with vicinal tetrasubstituted stereocenters in high yields with excellent enantioselectivities. The bimetalli
- Trost, Barry M.,Zhu, Chuanle
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supporting information
p. 9683 - 9687
(2020/12/21)
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- Preparation method of 1-aryl-1,2-dibromoethane
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The invention relates to a preparation method of 1-aryl-1,2-dibromoethane. The preparation method of 1-aryl-1,2-dibromoethane includes the steps: under a nitrogen atmosphere, a solvent, an aryl alkaneand N-bromosuccinimide are added in to a reaction tube in sequence, a dibromination reaction is conducted at 80-120 DEG C for 12-48 hours, then, the dibromination reaction is finished, the solvent isremoved through evaporation, and through column chromatography separation, 1-aryl-1,2-dibromoethane compounds are obtained. According to the preparation method of 1-aryl-1,2-dibromoethane, a synthesis technology is simple, reaction conditions are mild, the yield of 1-aryl-1,2-dibromoethane is high, and thus the preparation method of 1-aryl-1,2-dibromoethane is easy to industrialize.
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-
Paragraph 0015-0016
(2020/03/16)
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- Preparation of a novel bromine complex and its application in organic synthesis
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Although molecular bromine (Br2) is a useful brominating reagent, it is not easy to handle. Herein, we describe the preparation of a novel air-stable bromine complex prepared from 1,3-dimethyl-2-imidazolidinone (DMI) and Br2, which was identified to be (DMI)2HBr3 by spectral and X-ray techniques. This complex was then used to brominate olefins, carbonyl compounds, and aromatics, as well as in the Hofmann rearrangement. Yields of reaction products using this complex were almost the same or superior to those using other bromine alternatives.
- Nishio, Yuya,Yubata, Kotaro,Wakai, Yutaro,Notsu, Kotaro,Yamamoto, Katsumi,Fujiwara, Hideki,Matsubara, Hiroshi
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p. 1398 - 1405
(2019/02/07)
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- Atom-economical brominations with tribromide complexes in the presence of oxidants
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Bromination is an important transformation in organic synthesis, and novel efficient bromination techniques are still required. Herein, we demonstrate atom-economical brominations using (DMI)2HBr3, a novel tribromide complex, with oxidants such as DMSO and Oxone. Using this system, olefinic and aromatic brominations, as well as selective α-monobrominations of ketones proceeded well to afford the desired bromides in good yields. Importantly, in these reactions all of the bromine atoms in this complex are used to brominate.
- Yubata, Kotaro,Matsubara, Hiroshi
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supporting information
p. 1001 - 1004
(2019/03/13)
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- Visible-Light-Induced Regioselective C(sp3)-H Acyloxylation of Aryl-2 H-azirines with (Diacetoxy)iodobenzene
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A visible-light-promoted regioselective coupling of C(sp3)-H of aryl-2H-azirine and (diacetoxy)iodobenzene has been reported. Rose Bengal as an organophotoredox catalyst has been used in this reaction. The reaction proceeds under aerobic condition at room temperature. A variety of aryl-2H-azirines gives the corresponding acyloxylated azirines under this reaction conditions. The reaction goes through a radical pathway. The protocol is also applicable on gram-scale synthesis.
- De, Aramita,Santra, Sougata,Hajra, Alakananda,Zyryanov, Grigory V.,Majee, Adinath
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supporting information
p. 11735 - 11740
(2019/10/02)
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- Cyrene as a Bio-Based Solvent for the Suzuki-Miyaura Cross-Coupling
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The Suzuki-Miyaura (SM) cross-coupling is the most broadly utilized Pd-catalyzed C-C bond-forming reaction in the chemical industry. A large proportion of SM couplings employ dipolar aprotic solvents; however, current sustainability initiatives and increasingly stringent regulations advocate the use of alternatives that exhibit more desirable properties. Here we describe the scope and utility of the bio-derived solvent Cyrene in SM cross-couplings and evaluate its suitability as a reaction medium for this benchmark transformation from discovery to gram scale.
- Wilson, Kirsty L.,Murray, Jane,Jamieson, Craig,Watson, Allan J. B.
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supporting information
p. 650 - 654
(2017/12/26)
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- Method for synthesizing alpha,beta-dibromide
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The invention discloses a method for synthesizing alpha,beta-dibromide. The method is characterized in that a styrene compound as shown in the formula I is taken as a raw material, Zn-Al hydrotalciteZnAl-BrO3-LDHs of a bromate intercalation is taken as
- -
-
Paragraph 0032; 0033; 0034
(2018/04/01)
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- Dibromination of alkenes with LiBr and H2O2 under mild conditions
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Electron-rich and electron-poor alkenes, and alkenes bearing protecting groups can be efficiently and stereoselectively converted to trans-dibromides using LiBr/H2O2 and AcOH as a proton source in 1,4-dioxane. For most substrates addition of 0.1 mol% of PhTeTePh enhances the reaction rate and the yield of the products. Experimental data suggest that the brominating agent prepared in situ is molecular bromine and that LiBr assists the activation of H2O2 allowing bromination to occur using AcOH as a mild proton source in uncatalyzed experiments. Scale-up is feasible: 10.0 mmol of 1-octene was quantitatively converted to 1,2-dibromooctene in one hour of reaction at room temperature.
- Martins, Nayara Silva,Alberto, Eduardo E.
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supporting information
p. 161 - 167
(2017/12/28)
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- Mild and Efficient Vicinal Dibromination of Olefins Mediated by Aqueous Ammonium Fluoride
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A mild and efficient vicinal dibromination of olefins has been developed by using saturated aqueous ammonium fluoride solution as the promoter. Inexpensive and commercially available N -bromosuccinimide (NBS) was used as the brominating reagent. The corresponding vicinal dibromoalkanes could be obtained in good to excellent yields.
- Ng, Wing Hin,Shing, Tony K. M.,Yeung, Ying-Yeung
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supporting information
p. 419 - 424
(2018/02/23)
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- Intermolecular Carboamination of Unactivated Alkenes
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Herein, we report the first example of group transfer radical addition of O-vinylhydroxylamine derivatives onto unactivated alkenes. By utilizing O-vinylhydroxylamine derivatives as both the N- and C-donors, this reaction enables intermolecular carboamination of unactivated alkenes in an atom economical fashion. As the process is initiated through N-radical addition followed by C-transfer, linear carboamination products are afforded. This differs from canonical radical carbofunctionalization of olefins, which typically favors branched product owing to initiation by C-radical addition.
- Zhang, Yu,Liu, Haidong,Tang, Luning,Tang, Hai-Jun,Wang, Lu,Zhu, Chuan,Feng, Chao
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supporting information
p. 10695 - 10699
(2018/09/06)
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- One-Pot Strategy for Thiazoline Synthesis from Alkenes and Thioamides
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A convenient synthesis of a privileged pharmaceutical motif, thiazoline is accomplished. This reaction utilizes simple and readily available alkene and thioamide substrates in an intermolecular fashion via a simple one-pot procedure. A wide range of functional groups is tolerated, and the thiazoline product has been further utilized for the synthesis of the corresponding β-aminothiol and thiazole from routine hydrolysis and oxidation protocols.
- Alom, Nur-E,Wu, Fan,Li, Wei
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supporting information
p. 930 - 933
(2017/02/26)
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- Dehalogenation of vicinal dihalo compounds by 1,1′-bis(trimethylsilyl)-1: H,1′ H-4,4′-bipyridinylidene for giving alkenes and alkynes in a salt-free manner
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We report a transition metal-free dehalogenation of vicinal dihalo compounds by 1,1′-bis(trimethylsilyl)-1H,1′H-4,4′-bipyridinylidene (1) under mild conditions, in which trimethylsilyl halide and 4,4′-bipyridine were generated as byproducts. The synthetic protocol for this dehalogenation reaction was effective for a wide scope of dibromo compounds as substrates while keeping the various functional groups intact. Furthermore, the reduction of vicinal dichloro alkanes and vicinal dibromo alkenes also proceeded in a salt-free manner to afford the corresponding alkenes and alkynes.
- Rej, Supriya,Pramanik, Suman,Tsurugi, Hayato,Mashima, Kazushi
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supporting information
p. 13157 - 13160
(2017/12/26)
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- Electrochemical bromination of cyclic and acyclic enes using biphasic electrolysis
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A simple method of electrochemical bromination of a series of cyclic and acyclic enes (styrene and substituted styrenes, stilbene, indene, and cyclooctene) in a biphasic water-chloroform mixture mediated by bromide/bromine redox system is reported. Aqueous 25% NaBr/H2SO4 is used as the electrolyte. Regio- and stereoselective dibromination of enes is achieved. Moderate to excellent yields of the product (83-98%) is obtained depending on the substrate. Electrolyte reuse has also been demonstrated successfully using HBr in the dibromination of styrene.
- Kulangiappar,Ramaprakash,Vasudevan,Raju
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supporting information
p. 145 - 153
(2016/02/23)
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- Visible-Light Photoredox Catalyzed Three-Component Cyclization of 2H-Azirines, Alkynyl Bromides, and Molecular Oxygen to Oxazole Skeleton
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A novel three-component cyclization of 2H-azirines, alkynyl bromides, and molecular oxygen under visible-light photoredox catalysis at room temperature has been developed, which provides a direct approach to a wide range of substituted oxazoles in moderate to good yields.
- Chen, Lili,Li, Hongji,Li, Pinhua,Wang, Lei
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supporting information
p. 3646 - 3649
(2016/08/16)
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- Efficient bromination of olefins, alkynes, and ketones with dimethyl sulfoxide and hydrobromic acid
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The oxidative bromination of olefins, alkynes, and ketones has been developed with HBr as the brominating reagent and DMSO as the mild oxidant. The simple conditions, high bromide-atom-economy, as well as easy accessibility and low cost of DMSO and HBr make the present strategy prospective for the synthesis of dibrominated alkanes, dibrominated alkenes and α-bromoketones.
- Song, Song,Li, Xinwei,Sun, Xiang,Yuan, Yizhi,Jiao, Ning
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supporting information
p. 3285 - 3289
(2015/06/25)
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- I2-catalyzed synthesis of substituted imidazoles from vinyl azides and benzylamines
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A novel and efficient I2-catalyzed oxidative tandem cyclization of simple vinyl azides and benzylamines has been developed for the synthesis of substituted imidazoles. In this reaction, various substituted groups on vinyl azides and benzylamines proceed smoothly and the desired imidazoles are obtained in moderate to good yields.
- Xiang, Likui,Niu, Yanning,Pang, Xiaobo,Yang, Xiaodong,Yan, Rulong
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supporting information
p. 6598 - 6600
(2015/04/14)
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- Green and Efficient: Iron-Catalyzed Selective Oxidation of Olefins to Carbonyls with O2
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A mild and operationally simple iron-catalyzed protocol for the selective aerobic oxidation of aromatic olefins to carbonyl compounds is described. Catalyzed by a Fe(III) species bearing a pyridine bisimidazoline ligand at 1 atm of O2, α- and β-substituted styrenes were cleaved to afford benzaldehydes and aromatic ketones generally in high yields with excellent chemoselectivity and very good functional group tolerance, including those containing radical-sensitive groups. With α-halo-substituted styrenes, the oxidation took place with concomitant halide migration to afford α-halo acetophenones. Various observations have been made, pointing to a mechanism in which both molecular oxygen and the olefinic substrate coordinate to the iron center, leading to the formation of a dioxetane intermediate, which collapses to give the carbonyl product. (Chemical Equation).
- Gonzalez-De-Castro, Angela,Xiao, Jianliang
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supporting information
p. 8206 - 8218
(2015/07/15)
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- Effect of sodium acetate in atom transfer radical addition of polyhaloalkanes to olefins
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The atom transfer radical addition of polyhaloalkanes, such as bromotrichloromethane and polyfluoroalkyl iodine, to olefins smoothly proceeds in the presence of sodium acetate as an efficient auxiliary agent in dimethoxyethane. The present transition meta
- Sawama, Yoshinari,Nakatani, Ryosuke,Imanishi, Takahiro,Fujiwara, Yuta,Monguchi, Yasunari,Sajiki, Hironao
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p. 8657 - 8660
(2014/03/21)
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- Ti(OiPr)4/nBuLi: An attractive reagent system for [2+2+2] cyclotrimerisation reactions
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A convenient method for the [2+2+2] cyclotrimerisation of alkynes using Ti(OiPr)4/nBuLi is presented. Homotrimerisation of arylacetylenes proceeds within minutes with excellent regioselectivity. Moreover, the intermolecular construction of ABB heterotrimers can be achieved selectively from two different alkynes with similar electronic properties. The method is also suitable for the synthesis of pyridines.
- Rassadin,Nicolas,Six
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supporting information
p. 7666 - 7669
(2014/07/08)
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- Aqueous Et4NBrO3/KBr as a versatile and environmentally benign source of bromine for the selective trans-bromination of alkenes
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An aqueous solution of tetraethyl ammonium bromate and potassium bromide is found to be an environmentally benign source of bromine at ambient temperature. This reagent is used for selective trans-dibromination of several substituted alkenes. The reaction conditions are mild and the yield of the products are high and other possible by-products such as bromohydrin formation and aromatic substitution have not been observed.
- Das, Pranab Jyoti,Sarkar, Sudeshna
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p. 802 - 806
(2013/07/26)
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- Regio-and stereoselective hydroxybromination and dibromination of olefins using ammonium bromide and oxone
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An efficient protocol for the synthesis of vicinal bromohydrins and dibromides from olefins is presented. Various olefins are regio-and stereoselectively hydroxybrominated and dibrominated with anti fashion, following Markonikov's rule, using eco-friendly, non-toxic, and stable reagents such as NH4Br and oxone in CH3CN/H2O (1:1) and CH3CN without employing catalyst in moderate to excellent yields. Bromohydrins are formed instantaneously.
- MacHarla, Arun Kumar,Chozhiyath Nappunni, Rohitha,Nama, Narender
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supporting information; experimental part
p. 1401 - 1405
(2012/04/04)
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- Facile one-pot synthesis of α-bromoketones from olefins using bromide/bromate couple as a nonhazardous brominating agent
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A new method for the preparation of α-bromoketones from olefins using bromide/bromate couple as a nonhazardous brominating agent has been developed. Several α-bromoketones were successfully prepared from a variety of olefins by this method. This procedure is an alternative to conventional molecular bromine.
- Patil, Rajendra D.,Joshi, Girdhar,Adimurthy, Subbarayappa,Ranu, Brindaban C.
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experimental part
p. 2529 - 2532
(2009/09/06)
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- Comparative study of the vicinal functionalization of olefins with 2:1 bromide/bromate and iodide/iodate reagents
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A comparative evaluation was made on the syntheses of vicinal halohydrins, halo methyl ethers, and halo acetates from olefins using 2:1 Br-/BrO3- and I-/IO3- reagents. In many cases both reagents afforded products selectively in high yields. The highest halogen atom efficiencies attained were 97% and 93% for Br-/BrO3- and I-/IO3-, respectively. Of the two reagents, I-/IO3- was established to be the preferred reagent for vicinal functionalization of linear alkenes and also for halo acetate preparation. However, only Br-/BrO3- was effective for vicinal functionalization of trans-stilbene and chalcones.
- Agrawal, Manoj K.,Adimurthy, Subbarayappa,Ganguly, Bishwajit,Ghosh, Pushpito K.
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supporting information; experimental part
p. 2791 - 2797
(2009/08/08)
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- A bimetallic palladium(II) catalyzed synthesis of 1,2-dibromo compounds
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A bimetallic palladium(II) catalyst containing a triketone ligand and a bridging dinitrogen ligand oxidizes aromatic and cyclic aliphatic olefins in bromide-containing aqueous-THF to 1,2-dibromo compounds and bromohydrins. With aromatic olefins, the 1,2-dibromo products were obtained in a 70-80% yield and the bromohydrins in a 10-15% yield; this observation is opposition to that obtained in chloride containing medium where the chlorohydrin product predominates. The oxidation of 2,3-dihydrofuran gave trans-2,3- dibromotetrahydrofuran, 3-oxotetrahydrofuran, and 3-bromo-2- hydroxytetrahydrofuran in relative yields of 75%, 15%, and 10%, respectively. On the other hand, the oxidation of cyclopentene and cyclohexene affords only trans-1,2-dibromo products in about 90% yield. The stereochemistry is consistent with an anti-at-tack of bromide followed by decomposition involving attack of bromide from the coordination sphere of the Pd(II). The procedure outlined here is a convenient method for the one step synthesis of 1,2-dibromides.
- Qaseer
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- A Simple and Convenient Method for Epoxidation of Olefins without Metal Catalysts
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An easy method for epoxidation of olefins using bleach (sodium hypochlorite) and either a stoichiometric or catalytic amount of bromide ion has been developed. Without any transition metal catalyst a variety of non-activated olefins give epoxides in high yields and good selectivity at ambient conditions.
- Klawonn, Markus,Bhor, Santosh,Mehltretter, Gerald,Doebler, Christian,Fischer, Christine,Beller, Matthias
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p. 389 - 392
(2007/10/03)
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- An efficient bromination of alkenes using cerium(IV) ammonium nitrate (CAN) and potassium bromide
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Bromination of alkenes using a combination of potassium bromide and cerium(iv) ammonium nitrate (CAN) in a two phase system consisting of water and dichloromethane affords the corresponding dibromides in excellent yield. The reaction most likely involves the addition of the bromine radical generated from bromide ion by CAN and subsequent formation of the dibromide.
- Nair, Vijay,Panicker, Sreeletha B,Augustine, Anu,George, Tesmol G,Thomas, Siji,Vairamani
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p. 7417 - 7422
(2007/10/03)
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- Vanadium Bromoperoxidases Mimicking Systems: Bromohydrins Formation as Evidence of the Occurance of a Hypobromite-Like Vanadium Complex.
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In the aqueous phase of a two-phase (H2O-CH2Cl2) system mimicking the hydrophilic and the hydrophobic portions of vanadium dependent bromoperoxidases, (V-BrPO), a mono peroxovanadium complex, formed in situ by addition of H2O2 to NH4VO3, oxidizes Br(-) to a species whose nature is still largely unknown.Such species displays a bromine-like reactivity toward organic substrates dissolved in CH2Cl2.The observation that styrene, 1-methyl- and 2-methyl styrenes afford, together with dibromo-compounds, appreciable amounts of bromohydrins, suggests that a hypobromite-like species also formed.Evidence is presented that such a species is a vanadium complex.
- Andersson, Malin,Conte, Valeria,Furia, Fulvio Di,Moro, Stefano
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p. 2675 - 2678
(2007/10/02)
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- SYNTHESE, EIGENSCHAFTEN UND CARBONYL-INSERTIONS-REAKTIONEN VON TETRACARBONYLEISEN(0)-KOMPLEXEN para-SUBSTITUIERTER STYROLE
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The Fe(CO)4 η2-complexes of para-substituted styrenes (substituent=H, CH3, OCH3, Cl, F) can be obtained in good yields.Complexation changes drastically the chemical shifts and coupling constants of the vinyl protons.Reaction of the complexes wi
- Schmidt, Eckhart K.G.,Dogan, Mehmet
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