- 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
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supporting information
p. 13385 - 13388
(2021/12/17)
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- Nucleophilic halo-michael addition under lewis-base activation
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A simple and general conjugate nucleophilic halogenation is presented. The THTO/halosilane combination has shown the ability to act as a nucleophilic halide source in the conjugate addition to a variety of Michael acceptors. In addition, a straightforward diastereoselective halogen installation using α,β-unsaturated acyloxazolidinones as platforms has been developed.
- Laina-Martín, Víctor,Pérez, Ignacio,Fernández-Salas, Jose A.,Alemán, José
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supporting information
p. 12936 - 12939
(2019/11/05)
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- Hexamethonium bis(tribromide) (HMBTB) a recyclable and high bromine containing reagent
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A recyclable and high bromine containing di-(tribromide) reagent, hexamethonium bis(tribromide) (HMBTB) has been synthesized and utilized for the bromination of various organic substrates. The spent reagent hexamethonium bromide (HMB) can be effectively recycled by regenerating and reusing it without significant loss of activity. The crystalline and stable bis(tribromide) is an effective storehouse of very high percentage of active bromine requiring just half an equivalent of it for complete bromination. Both the Br3- moieties in HMBTB are nearly linear with Br-Br-Br angle of 179.55°.
- Paul, Bappi,Bhuyan, Bishal,Purkayastha, Debraj D.,Dhar, Siddhartha S.,Patel, Bhisma K.
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p. 5646 - 5650
(2015/09/21)
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- Nucleophilic substitution of α-haloenones with phenols
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The α-haloenones undergo cine-substitution upon reaction with phenolic reagents under basic conditions. A convenient method for the synthesis of push-pull aroxyenones was developed based on this reaction.
- Mareev, Alexander V.,Ushakov, Igor A.,Rulev, Alexander Yu.
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p. 1971 - 1974
(2015/03/30)
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- Experimental and Theoretical Study of an Intramolecular CF3-Group Shift in the Reactions of α-Bromoenones with 1,2-Diamines
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The reactions of trifluoromethylated 2-bromoenones and N,N′-dialkyl-1,2-diamines have been studied. Depending on the structures of the starting compounds, the formation of 2-trifluoroacetylpiperazine or 3-trifluoromethylpiperazine-2-ones was observed. The mechanism of the reaction is discussed in terms of multistep processes involving sequential substitution of bromine in the starting α-bromoenones and intramolecular cyclization of the captodative aminoenones as key intermediates to form the target heterocycles. The results of theoretical calculations are in perfect agreement with the experimental data. The unique role of the trifluoromethyl group in this reaction is demonstrated.
- Muzalevskiy, Vasily M.,Ustynyuk, Yury A.,Gloriozov, Igor P.,Chertkov, Vyacheslav A.,Rulev, Alexander Yu.,Kondrashov, Evgeniy V.,Ushakov, Igor A.,Romanov, Alexey R.,Nenajdenko, Valentine G.
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p. 16982 - 16989
(2015/11/16)
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- Halocarbocyclization versus dihalogenation: Substituent directed iodine(iii) catalyzed halogenations
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The nucleophilicity of the substituents in iodobenzene pre-catalysts have a huge impact on product selectivity in iodine(iii) triggered halogenations, steering the reactivity from solely carbocyclizations towards dihalogenations. Utilizing this catalyst-dependent reactivity a diastereo- and chemoselective dihalogenation method was established allowing the conversion of structurally and electronically diverse unsaturated compounds in excellent yields.
- Stodulski, Maciej,Goetzinger, Alissa,Kohlhepp, Stefanie V.,Gulder, Tanja
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supporting information
p. 3435 - 3438
(2014/03/21)
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- I2O5-mediated bromohydroxylation and dibromination of olefins using KBr in water
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An efficient and green bromohydroxylation and dibromination of various olefins mediated by I2O5 has been developed in this work. A series of olefins gave the corresponding α-bromo-alcohols and dibromides as the major products using KBr as the brominating reagent in aqueous medium at room temperature. The diastereo- and regio-selectivities are extremely high.
- Wang, Yajun,Wang, Jinxi,Xiong, Yun,Liu, Zhong-Quan
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supporting information
p. 2734 - 2737
(2014/05/06)
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- Direct sustainable bromination of alkenes in aqueous media and basic ionic liquids
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Electron-rich and electron-poor alkenes have been dibrominated using a rapid and sustainable procedure. The reactions were conducted in aqueous medium and basic ionic liquids which catalyzed the direct addition of bromine. The protocol leads to remarkable results, high yields under mild conditions, complete chemo- and stereo-selectivity and allows the recycling of ionic liquids, reducing costs, and environmental impact.
- Primerano, Patrizia,Cordaro, Massimiliano,Scala, Angela
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p. 4061 - 4063
(2013/07/25)
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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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- Alkoxybromination of olefins using ammonium bromide and oxone
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A mild, efficient, and highly regio- and stereoselective method for the methoxy and ethoxy bromination of olefins has been developed using NH 4Br as a bromine source and Oxone as an oxidant. Various kinds of olefins (aromatic, linear, and cyclic olefins) afforded the corresponding alkoxy brominated products in moderate to excellent yields. Taylor & Francis Group, LLC.
- Kumar, Macharla Arun,Naresh, Mameda,Rohitha, Chozhiyath Nappunni,Narender, Nama
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supporting information
p. 3121 - 3129
(2014/01/06)
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- Organocatalysis as a safe practical method for the stereospecific dibromination of unsaturated compounds
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Organocatalytic stereospecific dibromination of a wide variety of functionalized alkenes was achieved using a stable, inexpensive halogen source, 1,3-dibromo 5,5-dimethylhydantoin, and a simple thiourea catalyst at room temperature. The presence of a tertiary amine enhanced the rate of the dibromination reaction, and yields were good in various solvents, including aqueous solvents. The procedure was extended to alkynes and aromatic rings and to dichlorination reactions by using the 1,3-dichloro hydantoin derivative.
- Hernandez-Torres, Gloria,Tan, Bin,Barbas, Carlos F.
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supporting information; experimental part
p. 1858 - 1861
(2012/06/18)
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- Solvent-free bromination reactions with sodium bromide and oxone promoted by mechanical milling
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New solvent-free brominations of 1,3-dicarbonyl compounds, phenols, various alkenes including chalcones, azachalcones, 4-phenylbut-3-en-2-one, methyl cinnamate, styrene and 1,3-cyclohexadiene were efficiently achieved by employing sodium bromide and oxone under mechanical milling conditions. The brominated products were obtained in good to excellent yields.
- Wang, Guan-Wu,Gao, Jie
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experimental part
p. 1125 - 1131
(2012/06/04)
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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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- Synthesis and reactivity studies of a new reagent, ethyltriphenylphosphonium tribromide
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A new reagent, ethyltriphenyl phosphonium tribromide (ETPPTB), has been synthesized and studied. Results show that the reagent is quite efficient for various reactions such as organic bominations, acylations, and isothiocyanate preparation. Copyright
- Jamir, Latonglila,Alimenla,Kumar, Anil,Sinha, Dipak,Sinha, Upasana B.
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experimental part
p. 147 - 155
(2011/03/17)
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- Chemoselective C-C bond cleavage of epoxide motifs: Gold(I)-catalyzed diastereoselective [4+3] cycloadditions of 1-(1-Alkynyl)oxiranyl ketones and nitrones
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Cutting carbon! A novel facile strategy for the C-C bond cleavage of oxiranyl ketones has been developed. Carbophilic gold(I) activation of the alkyne side chain mediates a heterocyclization and subsequent C-C bond cleavage (see scheme).
- Wang, Tao,Zhang, Junliang
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scheme or table
p. 86 - 90
(2011/03/20)
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- Electrophilic bromination of alkenes, alkynes, and aromatic amines with iodic acid/potassium bromide under mild conditions
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Bromination of alkenes, alkynes, and aromatic amines has efficiently been carried out at room temperature in short reaction times using HIO 3/KBr in CH2Cl2/H2O (1:1) to prepare corresponding brominated compounds in excellent yields.
- Khazaei, Ardeshir,Zolfigol, Mohammad Ali,Kolvari, Eskandar,Koukabi, Nadiya,Soltani, Hamid,Bayani, Leyla Sharaf
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experimental part
p. 2954 - 2962
(2010/10/20)
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- Elctrophilic bromination of alkenes, alkynes, and aromatic amines with potassium bromide/orthoperiodic acid under mild conditions
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Bromination of alkenes, alkynes, and aromatic amines has efficiently been carried out at room temperature in short reaction times using potassium bromide/orthoperiodic acid in dichloromethane-water (1:1) to prepare the corresponding bromo compounds with excellent yields.
- Khazaei, Ardeshir,Zolfigol, Mohammad Ali,Kolvari, Eskandar,Koukabi, Nadiya,Soltani, Hamid,Komaki, Fatemeh
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experimental part
p. 3672 - 3676
(2010/04/05)
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- Microwave-assisted dehalogenation of α-haloketones by zinc and ammonium chloride in alcohol
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The treatment of α-haloketones with 1.5 equiv. of Zn and 1 equiv. of NH4Cl in ethanol for 0.5αmin gave the corresponding ketones with excellent yields under microwave irradiation. Vic-dibromides and 2,2-dibromoacetophenone can be efficiently debrominated to alkenes and acetophenones, respectively. Copyright Taylor & Francis Group, LLC.
- Li, Jian,Ye, Deju,Liu, Hong,Luo, Xiaoming,Jiang, Hualiang
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p. 567 - 575
(2008/04/12)
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- A new recyclable ditribromide reagent for efficient bromination under solvent free condition
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1,2-Dipyridiniumditribromide-ethane (DPTBE) has been synthesized and explored as a new efficient brominating agent. The crystalline ditribromide reagent is stable for months and acts as a safe source of bromine requiring just 0.5 equiv for complete bromination. It has high active bromine content per molecule and shows a remarkable reactivity compared to other tribromide reagents toward various substrates by just grinding the reagent and substrates in a porcelain mortar at room temperature. No organic solvent has been used during any stage of the reaction for substrates giving product as solid. Product can easily be isolated by just washing the highly water soluble 1,2- dipyridiniumdibromide-ethane (DPDBE) from the brominated product. The spent reagent can be recovered, regenerated, and reused without any significant loss.
- Kavala, Veerababurao,Naik, Sarala,Patel, Bhisma K.
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p. 4267 - 4271
(2007/10/03)
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- Poly(vinylpyrrolidone)-bromine complex; a mild and efficient reagent for selective bromination of alkenes and oxidation of alcohols
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Poly(vinylpyrrolidone)-bromine complex (PVP-Br2) is easily prepared and used as a mild and convenient reagent for selective bromination of alkenes and at the position α-hydrogen of active carbonyl compounds. Selective oxidation of benzylic alcohols in the presence of aliphatic alcohols were also achieved at room temperature.
- Lakouraj, Moslem Mansour,Tajbakhsh, Mahmood,Mokhtary, Masoud
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p. 481 - 483
(2007/10/03)
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- Structure-dependent oxidative bromination of unsaturated C-C bonds mediated by selectfluor
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A number of olefins were subjected to oxidative bromination using Selectfluor/KBr. For different types of substrates, addition, monobromine-substituted, or Hunsdiecker-Borodin reaction products can be readily afforded.
- Ye, Chengfeng,Shreeve, Jean'Ne M.
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p. 8561 - 8563
(2007/10/03)
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- A convenient halogenation of α,β-unsaturated carbonyl compounds with OXONE and hydrohalic acid (HBr,HCl)
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Mixtures of OXONE and hydrobromic acid or hydrochloric acid afford solutions of bromine or chlorine, respectively, α-Bromo- or α-chloro-α,β-unsaturated carbonyl compounds were prepared by addition of hydrobromic acid or hydrochloric acid to the mixture of
- Kim, Kyoung-Mahn,Park, In-Hwan
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p. 2641 - 2644
(2007/10/03)
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- Synthesis of allenes from allylic alcohol derivatives bearing a bromine atom using a palladium(0)/diethylzinc system
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A general and efficient synthesis of allenes using a palladium(0)/diethylzinc system is described. Treatment of mesylates or trichloroacetates of (E)- or (Z)-2-bromoalk-2-en-1-ols with diethylzinc in the presence of a catalytic amount of palladium(0) affords allenes bearing an aminoalkyl, alkyl, or aryl substituent(s) in good to high yields. No transfer of chirality from the stereogenic center carrying the mesyloxy group to the allene was observed.
- Ohno, Hiroaki,Miyamura, Kumiko,Tanaka, Tetsuaki,Oishi, Shinya,Toda, Ayako,Takemoto, Yoshiji,Fujii, Nobutaka,Ibuka, Toshiro
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p. 1359 - 1367
(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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- On the effect of ring substituents in the carbonylation of aziridines
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The effect of ring substituents on the cobalt carbonyl-catalyzed carbonylation of functionalized aziridines to β-lactams has been investigated. A variety of aziridines with different substituents and stereochemistry has been synthesized and subjected to carbonylation. The ring expansion to β-lactam takes place in the absence of an electron-withdrawing substituent and higher yields are always obtained for cis-aziridines. Moreover, the regioselectivity of the reaction is affected by the nature of substituents at ring carbon atoms.
- Davoli, Paolo,Forni, Arrigo,Moretti, Irene,Prati, Fabio,Torre, Giovanni
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p. 1801 - 1812
(2007/10/03)
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- A radical based addition-elimination route for the preparation of indoles
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Indoles, including tricyclic derivatives, are produced by cyclisations of aryl radicals onto vinyl halides followed by elimination of halide radical and tautomerism of the resulting product; the aryl radicals are produced using "clean methodology" either by reaction of iodide ions with arenediazonium salts or by reaction of phosphorus-centred radicals with aryl iodides. The Royal Society of Chemistry 2000.
- Murphy, John A.,Scott, Karen A.,Sinclair, Rhoha S.,Martin, Concepcion Gonzalez,Kennedy, Alan R.,Lewis, Norman
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p. 2395 - 2408
(2007/10/03)
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- A new synthesis of indoles
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Aryl radical cyclisation onto appropriate vinyl bromides leads to a new route to indoles.
- Murphy, John A.,Scott, Karen A.,Sinclair, Rhona S.,Lewis, Norman
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p. 7295 - 7298
(2007/10/03)
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- Modification of chemical reactivity upon cyclodextrin encapsulation: Asymmetric bromination of chalcone and benzylideneacetone
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Asymmetric bromination of chalcone and benzylideneacetone (trans-isomers) in crystalline β-cyclodextrin complex was studied. While bromination of chalcone in the absence of β-cyclodextrin yields erythro-dibromide, bromination of β-cyclodextrin-chalcone complex results in the formation of a mixture of erythro- and threo-dibromides respectively in the ratio 80:20. Complexation does not induce any variation in the bromination pattern in the case of trans-benzylideneacetone. These observations have been accounted for in terms of different conformations of the enones in the β-cyclodextrin-enone complexes. Complex formation between the substrate and cyclodextrin has been confirmed by various physical methods.
- Pitchumani, Kasi,Velusamy, Ponnusamy,Sabithamala, Santhamoorthy,Srinivasan, Crockalingam
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p. 7903 - 7912
(2007/10/02)
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- LES TRIBROMURES DE PHOSPHONIUMS. AGENTS DE BROMINATION DE SUBSTRATS ORGANIQUES
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The reactivities and selectivities of phosphonium tribromides 1-4 towards ketones and their ketals, in the presence of other functional group reactive toward bromide (free enolic position, activated aromatic ring or double bond), are studied and compared with the trimethyl phenyl ammonium tribromide 5.The abilities of the two kinds of tribromides are similar, with a better selectivity of phosphonium salts toward unsaturated ketones, which is probably induced by the greater stability of the ion-pair in phosphonium salts.They act essentially by the tribromide without specific bond interactions between phosphorus and heteroatom of the substrate.
- Cristau, Henri-Jean,Torreilles, Eliane,Morand, Philippe,Christol, Henri
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p. 357 - 368
(2007/10/02)
-
- REAGENTS AND SYNTHETIC METHODS 38. 4-(DIMETHYLAMINO)PYRIDINIUM BROMIDE PERBROMIDE AS A NEW BROMINATING AGENT FOR ORGANIC COMPOUNDS.
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A new and stable brominating agent for several organic compounds is described.
- Arrieta, A.,Ganboa, I.,Palomo, C.
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p. 939 - 946
(2007/10/02)
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- α-Keto Dianion Precursors via Conjugate Additions to Cyclic α-Bromo Enones
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Successful conjugate to 2-bromocyclohexenone and 2-bromocyclopentenone have been achieved with a variety of lithium homocuprates, mixed cyanocuprates, and lithium tri-sec-butylborohydride as well.In all cases the resulting α-bromo enolate anions could be
- Kowalski, Conrad J.,Weber, Ann E.,Fields, Kevin W.
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p. 5088 - 5093
(2007/10/02)
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- A Convenient Synthesis of β-(1-Imidazoyl)enones from α,β-Dibromoketones
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As the convenient preparative method of β-(substituted)-phenyl-β-(1-imidazolyl)enones, we succeeded in the preparation of β-aryl-β-(1-imidazolyl)enones from α,β-dibromo-β-arylketones with imidazole in the presence of triethylamine.
- Kashima, C.,Shimizu, M.,Tajima, T.
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p. 961 - 964
(2007/10/02)
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