19922-83-9Relevant academic research and scientific papers
Reaction of Diisobutylaluminum Borohydride, a Binary Hydride, with Selected Organic Compounds Containing Representative Functional Groups
Amberchan, Gabriella,Snelling, Rachel A.,Moya, Enrique,Landi, Madison,Lutz, Kyle,Gatihi, Roxanne,Singaram, Bakthan
supporting information, p. 6207 - 6227 (2021/05/06)
The binary hydride, diisobutylaluminum borohydride [(iBu)2AlBH4], synthesized from diisobutylaluminum hydride (DIBAL) and borane dimethyl sulfide (BMS) has shown great potential in reducing a variety of organic functional groups. This unique binary hydride, (iBu)2AlBH4, is readily synthesized, versatile, and simple to use. Aldehydes, ketones, esters, and epoxides are reduced very fast to the corresponding alcohols in essentially quantitative yields. This binary hydride can reduce tertiary amides rapidly to the corresponding amines at 25 °C in an efficient manner. Furthermore, nitriles are converted into the corresponding amines in essentially quantitative yields. These reactions occur under ambient conditions and are completed in an hour or less. The reduction products are isolated through a simple acid-base extraction and without the use of column chromatography. Further investigation showed that (iBu)2AlBH4 has the potential to be a selective hydride donor as shown through a series of competitive reactions. Similarities and differences between (iBu)2AlBH4, DIBAL, and BMS are discussed.
Chiral guanidine catalyzed acylative kinetic resolution of racemic 2-bromo-1-arylethanols
Sawada, Erika,Nakata, Kenya
, p. 371 - 373 (2021/03/16)
In this study, chiral guanidine catalyzed acylative kinetic resolution of racemic 2-bromo-1-arylethanols was achieved with high selectivity. Irrespective of the electronic nature and the substitution patterns on the aromatic rings, a variety of substrates were suitable for this reaction. The branched acyl component was considered to be optimal for obtaining high s-values. The transition state of the reaction was proposed based on the absolute configuration of the obtained product.
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.
Asymmetric Catalytic Meerwein-Ponndorf-Verley Reduction of Ketones with Aluminum(III)-VANOL Catalysts
Guan, Yong,Mohammadlou, Aliakbar,Staples, Richard,Sullivan, Ryan P.,Wulff, William D.,Yin, Xiaopeng,Zheng, Li
, p. 7188 - 7194 (2020/07/21)
We report herein an efficient aluminum-catalyzed asymmetric MPV reduction of ketones with broad substrate scope and excellent yields and enantiomeric inductions. A variety of aromatic (both electron-poor and electron-rich) and aliphatic ketones were converted to chiral alcohols in good yields with high enantioselectivities (26 examples, 70-98percent yield and 82-99percent ee). This method operates under mild conditions (-10 °C) and low catalyst loading (1-5 mol percent). Furthermore, this process is catalyzed by the earth-abundant main-group element aluminum and employs 2-propanol as the hydride source.
One-pot synthesis of 4-aryl-2-aminothiazoles from styrenes and thioureas promoted by tribromoisocyanuric acid
de Andrade, Vitor S.C.,de Mattos, Marcio C.S.
supporting information, (2020/07/03)
A simple and efficient one-pot protocol has been developed for the conversion of styrenes into 4-aryl-2-aminothiazoles using readily available starting materials. Tribromoisocyanuric acid was successfully used for the co-bromination and oxidation of styrenes to give phenacyl bromides, which in the presence of thioureas produced the corresponding 4-aryl-2-aminothiazoles in 48–70% yield. The protocol involves three reactions in one process: a tandem (formation of phenacyl bromides from styrenes) followed by a telescoped (conversion to thiazole) reaction.
Asymmetric synthesis of α-bromohydrins by carrot root as biocatalyst and conversion to enantiopure β-hydroxytriazoles and styrene oxides using click chemistry and SN2 ring-closure
Hosseinzadeh, Rahman,Mohadjerani, Maryam,Mesgar, Sakineh
, p. 583 - 591 (2019/02/17)
In this study we have combined the bioreduction of α-bromoketones using carrot root as biocatalyst and click chemistry for the preparation of enantiopure β-hydroxytriazoles in excellent enantiomeric excesses and yields. Moreover, we have utilized chiral α-halohydrins for the synthesis of enantiopure styrene oxides in very good yields and enantiomeric excesses. Structural assignments of the products were based on their 1H and 13C NMR data and their optical rotations. The enantiomeric excess of the chiral products was obtained by HPLC analysis.
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.
Selective Asymmetric Transfer Hydrogenation of α-Substituted Acetophenones with Bifunctional Oxo-Tethered Ruthenium(II) Catalysts
Yuki, Yamato,Touge, Taichiro,Nara, Hideki,Matsumura, Kazuhiko,Fujiwhara, Mitsuhiko,Kayaki, Yoshihito,Ikariya, Takao
supporting information, p. 568 - 574 (2017/12/13)
A practical method for the asymmetric transfer hydrogenation of α-substituted ketones was developed utilizing oxo-tethered N-sulfonyldiamine-ruthenium complexes. Reduction by HCO2H and HCO2K in a mixed solvent of EtOAc/H2O allowed for the selective synthesis of halohydrins from 2-bromoacetophenone (98%) and 2-chloroacetophenone (>99%), leading to suppressed undesired side reactions stemming from formylation under the typical reaction conditions using an azeotropic 5:2 mixture of HCO2H and Et3N. A range of functional groups, such as halogens, methoxy, nitro, dimethylamino, and ester groups, were well tolerated, highlighting the potential of this method. Nearly complete selectivity with a preferable ee was maintained even with a substrate/catalyst (S/C) ratio of 5000. This catalyst system was also effective for the asymmetric reduction of α-sulfonated ketones without eroding the leaving group. (Figure presented.).
Iridium-Catalyzed Asymmetric Hydrogenation of Halogenated Ketones for the Efficient Construction of Chiral Halohydrins
Yin, Congcong,Wu, Weilong,Hu, Yang,Tan, Xuefeng,You, Cai,Liu, Yuanhua,Chen, Ziyi,Dong, Xiu-Qin,Zhang, Xumu
supporting information, p. 2119 - 2124 (2018/04/30)
Iridium-catalyzed asymmetric hydrogenation of prochiral halogenated ketones was successfully developed to prepare various chiral halohydrins with high reactivities and excellent enantioselectivities under basic reaction condition (up to >99% conversion, 99% yield, >99% ee). Moreover, gram-scale experiment was performed well in the presence of just 0.005 mol% (S/C=20 000) Ir/f-amphox catalyst with 99% yield and >99% ee. (Figure presented.).
Halohydrin and its derivatives low priced high-efficient synthetic method (by machine translation)
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Paragraph 0060; 0061; 0062; 0063, (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)
