60655-81-4Relevant academic research and scientific papers
Alkene, Bromide, and ROH – How To Achieve Selectivity? Electrochemical Synthesis of Bromohydrins and Their Ethers
Bityukov, Oleg V.,Nikishin, Gennady I.,Terent'ev, Alexander O.,Vil', Vera A.
supporting information, p. 3070 - 3078 (2021/05/10)
Bromohydrins and their ethers were electrochemically synthesized via hydroxy- and alkoxybromination of alkenes using potassium bromide and water or alcohols. High selectivity of bromohydrins formation was achieved only with the use of DMSO as the solvent and an acid as the additive. The proposed combination of starting reagents, additives, and solvents allowed to form bromohydrins or their ethers selectively despite the variety of side-products (epoxides, dibromides, diols). Bromohydrins were obtained in high yields, up to 96%, with a broad substrate scope in an undivided electrochemical cell equipped with glassy carbon and platinum electrodes at high current density. (Figure presented.).
Electrochemical bromofunctionalization of alkenes in a flow reactor
Seitz, Jakob,Wirth, Thomas
supporting information, p. 6892 - 6896 (2021/08/20)
The bromination of organic molecules has been extensively studied to date, yet there is still a demand for safe and sustainable methodologies. Hazardous reagents, selectivity, low atom economy and waste production are the most persisting problems of brominating reagents. The electrochemical oxidation of bromide to bromine is a viable strategy to reduce waste by avoiding chemical oxidants. Furthermore, thein situgeneration of reactive intermediates minimizes the risk of hazardous reagents. In this work, we investigate the electrochemical generation of bromine from hydrobromic acid in a flow electrochemical reactor. Various alkenes could be converted to their corresponding dibromides, bromohydrines, bromohydrin ethers and cyclized products in good to excellent yields.
Lipase mediated enzymatic kinetic resolution of phenylethyl halohydrins acetates: A case of study and rationalization
Fonseca, Thiago de Sousa,Vega, Kimberly Benedetti,da Silva, Marcos Reinaldo,de Oliveira, Maria da Concei??o Ferreira,de Lemos, Telma Leda Gomes,Contente, Martina Letizia,Molinari, Francesco,Cespugli, Marco,Fortuna, Sara,Gardossi, Lucia,de Mattos, Marcos Carlos
, (2020/02/18)
Racemic phenylethyl halohydrins acetates containing several groups attached to the aromatic ring were resolved via hydrolysis reaction in the presence of lipase B from Candida antarctica (Novozym 435). In all cases, the kinetic resolution was highly selective (E > 200) leading to the corresponding (S)-β-halohydrin with ee > 99 %. However, the time required for an ideal 50 % conversion ranged from 15 min for 2,4-dichlorophenyl chlorohydrin acetate to 216 h for 2-chlorophenyl bromohydrin acetate. Six chlorohydrins and five bromohydrins were evaluated, the latter being less reactive. For the β-brominated substrates, steric hindrance on the aromatic ring played a crucial role, which was not observed for the β-chlorinated derivatives. To shed light on the different reaction rates, docking studies were carried out with all the substrates using MD simulations. The computational data obtained for the β-brominated substrates, based on the parameters analysed such as NAC (near attack conformation), distance between Ser-O and carbonyl-C and oxyanion site stabilization were in agreement with the experimental results. On the other hand, the data obtained for β-chlorinated substrates suggested that physical aspects such as high hydrophobicity or induced change in the conformation of the enzymatic active site are more relevant aspects when compared to steric hindrance effects.
Cascade bio-hydroxylation and dehalogenation for one-pot enantioselective synthesis of optically active β-halohydrins from halohydrocarbons
Cui, Hai-Bo,Xie, Ling-Zhi,Wan, Nan-Wei,He, Qing,Li, Zhi,Chen, Yong-Zheng
supporting information, p. 4324 - 4328 (2019/08/21)
A stereoselective hydroxylation and enantioselective dehalogenation cascade reaction was developed for the synthesis of optically active β-haloalcohols from halohydrocarbons. This cascade system employed P450 and halohydrin dehalogenase as two compatible biocatalysts, allowing a straightforward, greener and efficient access to β-halohydrins with excellent enantioselectivities (98-99%).
Tandem transfer hydrogenation-epoxidation of ketone substrates catalysed by alkene-tethered Ru(ii)-NHC complexes
Malan, Frederick P.,Singleton, Eric,Van Rooyen, Petrus H.,Landman, Marilé
supporting information, p. 8472 - 8481 (2019/06/14)
A series of nine cyclopentadienyl Ru(ii)-NHC complexes (1-9) have been synthesised by systematically varying the ligand and/or ligand substituents: η5-C5H4R′ (R′ = H, Me), EPh3 (E = P, As), NHC (Im, BIm), where NHC = Im(R)(R′) (R, R′ = Me, Bn, 4-NO2Bn, C2H4Ph, C4H7). Each of the Ru(ii)-NHC complexes features an N-alkenyl tether to attain bidentate NHC ligands. All complexes found application as catalysts in the tandem transfer hydrogenation and epoxidation reactions of carbonyl substrates. The catalytic activity of the complexes was shown to be similar, with efficiencies of up to 69% conversion after 18 hours and varying alcohol:epoxide selectivity for a variety of electronically diverse carbonyl substrates. Complex 3, with a nitro-containing substituent on the NHC ligand, was the only complex that showed preference for the alcohol product over the epoxide after 18 hours of reaction time.
Oxidative β-Halogenation of Alcohols: A Concise and Diastereoselective Approach to Halohydrins
Ai, Lingsheng,Wang, Weijin,Wei, Jialiang,Li, Qing,Song, Song,Jiao, Ning
, p. 437 - 441 (2019/02/26)
β-Halohydrins bearing transformable halo- and hydroxyl groups, are easily converted into various valuable blocks in organic and pharmaceutical synthesis. A diastereoselective β-halogenation of benzylic alcohols was achieved under simple and low-cost conditions, which provided a direct synthesis of β-halohydrins. The simple reaction conditions, easily available reagents, high diastereoselectivities, and additional oxidant-free make this reaction very attractive and practical.
A new entry of highly selective and nucleophilic BrH2C-and CLH2c-titanium complexes for carbonyl coupling
Yan, Tu Hsin,Ananthan, Bakthavachalam,Chang, Su Haur
, p. 778 - 787 (2019/01/24)
The direct coupling of various aldehydes and ketones with CH2Br2 or CH2Cl2 promoted by TiCl4-Mg bimetallic complex provides an extremely simple, practical, and efficient approach for the construction of bromomethyl or chloromethyl carbinols. The high chemoselectivity of this chemistry is illus-trated by the TiCl4-Mg-promoted selective coupling of CH2Br2 or CH2Cl2 with an aldehyde in the presence of ketone and selective transfer of CH2Br or CH2Cl to saturated carbonyl moiety. This protocol is also suitable for sterically hindered and enoliza-ble carbonyl compounds.
Halohydrin and its derivatives low priced high-efficient synthetic method (by machine translation)
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Paragraph 0040; 0041; 0042; 0043, (2017/08/25)
The invention discloses a halohydrin low priced high-efficient synthetic method, the organic solvent of formula I shown in the olefin compound with a halide, sulfoxide and additive mixing, by the olefin of hydroxy halogenate reaction, can be a high selectivity of the halohydrin the system results in the type II shown, wherein R1 , R2 , R3 , R4 , R5 And R6 Are selected from hydrogen, halogen, alkyl, hydroxyalkyl, alkoxy, ester, acyl, amido, dialkyl amino, aryl, substituted aromatic, heterocyclic aromatic group or substituted heterocyclic aromatic, R1 , R2 , R3 , R4 , R5 And R6 The presence of the respective independent may be identical or different; or R1 And R2 , R1 And R3 , R2 And R4 , R3 And R4 , R5 And R6 Combining to form a cycloalkyl or substituted cycloalkyl, benzo ring alkyl or substituted cycloalkyl, heterocycle or substituted heterocycle; M selected from hydrogen, lithium, sodium, potassium, cesium, beryllium, magnesium, calcium, strontium, barium, zinc, copper, iron, ammonium or tetraalkyl ammonium; X chlorine, bromine or iodine. (by machine translation)
One-pot synthesis of α-bromo- and α-azidoketones from olefins by catalytic oxidation with in situ-generated modified IBX as the key reaction
Chandra, Ajeet,Parida, Keshaba Nanda,Moorthy, Jarugu Narasimha
supporting information, p. 5827 - 5832 (2017/09/09)
Simple one-pot protocols for the syntheses of α-bromoketones and α-azidoketones starting from olefins have been developed by employing catalytic oxidation of the intermediary bromohydrins with in situ-generated modified IBX as the key reaction. The improved procedure involves initial formation of bromohydrin by the reaction of olefin with NBS in acetonitrile-water mixture (1:1) at rt followed by oxidation with in situ-generated 3,4,5,6-tetramethyl-2-iodoxybenzoic acid (TetMe-IBX), produced in catalytic amounts from 3,4,5,6-tetramethyl-2-iodobenzoic and Oxone. α-Bromoketones are further converted in the same pot to the corresponding α-azidoketones using NaN3/NaHCO3. The one-pot conversions are versatile for a variety of olefins that include cyclic as well as acyclic aliphatic olefins and electron-rich and electron-deficient styrenes. Chemoselective bromohydroxylation of electron-rich double bond and subsequent oxidation to the α-bromoketone is demonstrated for a substrate that contains both electron-rich and deficient double bonds.
From simple organobromides or olefins to highly value-added bromohydrins: A versatile performance of dimethyl sulfoxide
Song, Song,Huang, Xiaoqiang,Liang, Yu-Feng,Tang, Conghui,Li, Xinwei,Jiao, Ning
supporting information, p. 2727 - 2731 (2015/05/27)
A novel and efficient direct transformation of secondary bromides or olefins to highly value-added bromohydrins has been disclosed. Dimethyl sulfoxide (DMSO), a cheap and common solvent, performs its versatile role as a solvent, an essential oxidant, and also as an oxygen source in this bromohydrin synthesis.
