27786-05-6Relevant academic research and scientific papers
Pentylpyridinium tribromide: A vapor pressure free room temperature ionic liquid analogue of bromine
Salazar, José,Dorta, Romano
, p. 1318 - 1320 (2004)
The synthesis and characterization of the room temperature ionic liquid pentylpyridinium tribromide (2) is described. Tribromide 2 was used as a vapor pressure free bromine analogue for the bromination of ketones, aromatics, alkenes, and alkynes. The brominations were carried out in the absence of organic solvents and in most cases the only extraction solvent needed was water. Selectivities and reactivities were shown to be superior to current protocols. The spent reagent pentylpyridinium bromide (1) was easily recycled.
Inhibition of the Bromine-catalysed Isomerisation of α,β-Dibromostyrene by Graphite
Kodomari, Mitsuo,Tanaka, Nobuhisa,Yamamura, Seizi,Yoshitomi, Suehiko
, p. 1850 - 1851 (1987)
Phenylacetylene is stereoselectively brominated by molecular bromine adsorbed on graphite in carbontetrachloride, to produce E-α-β-dibromostyrene; isomerisation of the E-isomer to the Z-isomer, usually catalysed by bromine, is inhibited by graphite.
TEMPO-Regulated Regio- and Stereoselective Cross-Dihalogenation with Dual Electrophilic X+ Reagents
Kong, Yi,Cao, Tongxiang,Zhu, Shifa
supporting information, p. 3004 - 3010 (2021/08/23)
A TEMPO catalyzed cross-dihalogenation reaction was established via redox-regulation of the otherwise complex system of dual electrophilic X+ reagents. Formally, the ICl, BrCl, I2 and Br2 were generated in-situ, which enabled high regio- or stereoselective access to a myriad of iodochlorination, bromochlorination and homo-dihalogenation products with a wide spectrum of functionalities. With its mild conditions and operational simplicity, this method could enable wide applications in organic synthesis, which was exemplified by divergent synthesis of two pharmaceuticals. Detailed mechanistic investigations via radical clock reaction, pinacol ring expansion and Hammett experiments were conducted, which confirmed the intermediacy of halonium ion. In addition, a dynamic catalytic model based on the versatile catalytic role of TEMPO was proposed to explain the selective outcomes.
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
Rej, Supriya,Pramanik, Suman,Tsurugi, Hayato,Mashima, Kazushi
supporting information, p. 13157 - 13160 (2017/12/26)
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.
Halocarbocyclization versus dihalogenation: Substituent directed iodine(iii) catalyzed halogenations
Stodulski, Maciej,Goetzinger, Alissa,Kohlhepp, Stefanie V.,Gulder, Tanja
supporting information, p. 3435 - 3438 (2014/03/21)
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.
Brominations with Pr4NBr9 as a solid reagent with high reactivity and selectivity
Beck, Thorsten M.,Haller, Heike,Streuff, Jan,Riedel, Sebastian
, p. 740 - 747 (2014/04/03)
Tetrapropylammonium nonabromide (Pr4NBr9) is introduced as a room-temperature solid reagent for rapid bromination reactions of various substrates. The reagent exhibits reactivity similar to that of elemental bromine, but shows higher selectivity and it is easier and safer to store and to handle. Georg Thieme Verlag Stuttgart · New York.
Method for transforming alkynes into (E)-dibromoalkenes
Xiang, Jiannan,Yuan, Rui,Wang, Ruijia,Yi, Niannian,Lu, Linghui,Zou, Huaxu,He, Weimin
, p. 11378 - 11382 (2015/01/09)
The highly stereoselective bromination of alkynes has been realized by using copper(II) bromide as both the reacting partner and the catalyst, offering a generally efficient synthesis of (E)-dibromoalkenes. The reaction conditions are exceptionally mild, and a wide range of functional groups are well tolerated.
K 2S 2O 8-mediated difunctionalization of C≡C bonds in water: A simple and efficient approach to α, α -dihaloacetophenones from phenylacetylenes and NaX
Wang, Jing-Yu,Jiang, Qing,Guo, Can-Cheng
supporting information, p. 3130 - 3138 (2015/10/12)
A novel K2S2O8-mediated oxy-1,1-dihalogenation of alkynes with NaX in the presence of water has been developed, affording α,α-dihaloacetophenones in moderate to good yields. The advantages of this reaction are mild reaction conditions, operational simplicity, and use of pure water as reaction medium. A plausible reaction mechanism is proposed on the basis of mechanistic studies.
Synthesis of 1,1,1-trifluorobut-3-yn-2-ones and their reactions with N-nucleophiles
Muzalevskiy, Vasiliy M.,Iskandarov, Anton A.,Nenajdenko, Valentine G.
, p. 342 - 344 (2015/02/19)
Bromination of 4-aryl-1,1,1-trifluorobut-3-yn-2-ones gives 4-aryl-3,4-dibromo-1,1,1-trifluorobut-3-en-2-ones whose reactivity towards N-nucleophiles (hydrazine and ethylenediamine) was investigated.
Halodeboronation of organotrifluoroborates using tetrabutylammonium tribromide or cesium triiodide
Yao, Min-Liang,Kabalka, George W.,Blevins, David W.,Reddy, Marepally Srinivasa,Yong, Li
experimental part, p. 3738 - 3743 (2012/06/30)
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.
