36082-04-9Relevant academic research and scientific papers
The Conversion of α-Bromo-β-Dicarbonyls to Vicinal Tricarbonyls Using Dimethyldioxirane and Base
Coats, Steven J.,Wasserman, Harry H.
, p. 7735 - 7738 (1995)
Vicinal tricarbonyls are prepared from α-bromo-β-dicarbonyl precursors by base promoted oxygen transfer from dimethyldioxirane.The α-bromo-β-dicarbonyls were prepared by the reaction of CuBr2 and benzene (Koser's reagent) with a β-dicarbonyl system.
Lipophilic indole mediated chemoselective α-monobromination of 1,3-dicarbonyl compounds
Wong, Jonathan,Ke, Zhihai,Yeung, Ying-Yeung
, (2020/03/04)
A mild and efficient mono-selective bromination of 1,3-dicarbonyl compounds has been developed using lipophilic indole catalysts. Inexpensive and commercially available N-bromosuccinimide (NBS) was used as the brominating reagent. The selectivity was further enhanced when using stoichiometric amount of 3-bromoindole species. Mechanistic studies reveal that the indole catalyst has dual functions in the mono-bromination process.
Synthesis of (?)-Hebelophyllene E: An Entry to Geminal Dimethyl-Cyclobutanes by [2+2] Cycloaddition of Alkenes and Allenoates
Wiest, Johannes M.,Conner, Michael L.,Brown, M. Kevin
supporting information, p. 4647 - 4651 (2018/03/27)
The first synthesis of hebelophyllene E is presented, along with assignment of its previously unknown relative configuration through synthesis of epi-ent-hebelophyllene E. Development of a catalytic enantioselective [2+2] cycloaddition of alkenes and alle
Novel Metal- and Mineral-Acid-Free Synthesis of Organic Ammonium Tribromides and Application of Ethylenephenanthrolium Bistribromide for Bromination of Active Methylene Group of 1,3-Diketones and β-Ketoesters
Dey, Rupa Rani,Paul, Bappi,Dhar, Siddhartha Sankar
supporting information, p. 724 - 736 (2015/10/29)
A novel procedure for the preparation of organic ammonium tribromides (OATBs) is described from their corresponding bromides. Quaternary ammonium bromides (QABs) and a N,N′-heterocyclic dibromide are efficiently oxidized to their corresponding monotribromides and bistribromide by m-chloroperbenzoic acid (MCPBA) in the presence of 2 and 4 equiv of KBr, respectively. The reactions are carried out in an aqueous medium without the use of any mineral acid or metal catalyst/promoters. A variety of tribromides are synthesized in very good yields including a hitherto unknown reagent, 1,10-(ethane-1, 2-diyl)phenanthrolinediium bistribromide (EPDBT). EPDBT is investigated as brominating agent and found to be highly effective for selective bromination of active methylene groups of a variety of 1,3-diketones and β-ketoesters. GRAPHICAL ABSTRACT.
Total synthesis of epothilone D: The nerol/macroaldolization approach
Wessjohann, Ludger A.,Scheid, Guenther O.,Eichelberger, Uwe,Umbreen, Sumaira
, p. 10588 - 10595 (2013/11/19)
A highly convergent and stereocontrolled synthesis of epothilone D (4) is reported. Key features are a cheap and Z-selective synthesis of the northern half based on nerol and acetoacetate and chromium(II)-mediated Reformatsky reactions as a powerful tool for chemoselective asymmetric carbon-carbon bond formations, including an unusual stereospecific macroaldolization.
Selective monobromination of 1,3-diones with N-bromosaccharin/Mg(ClO 4)2 system in solution and under solvent-free conditions
Alinezhad, Heshmatollah,Tajbakhsh, Mahmood,Tehrani, Shahram Shahriari
experimental part, p. 1543 - 1546 (2011/12/04)
N-Bromosaccharin/Mg(ClO4)2 is an effective and regioselective system for α-monobromination of 1,3-dicarbonyl compounds. A wide variety of β-keto esters and 1,3-diketones in reaction with this system afforded a regioselectively α-mono
A mild and regioselective method for α-bromination of β-keto esters and 1,3-diketones using bromodimethylsulfonium bromide (BDMS)
Khan, Abu T.,Ali, Md. Ashif,Goswami, Papori,Choudhury, Lokman H.
, p. 8961 - 8963 (2007/10/03)
Bromodimethylsulfonium bromide has been found to be an effective and regioselective reagent for α-monobromination of β-keto esters and 1,3-diketones. A wide variety of β-keto esters and 1,3-diketones undergo chemoselective α-monobromination with excellent yields at 0-5 °C or room temperature. The notable advantages of this protocol are no need of chromatographic separation, use of less hazardous reagent than molecular bromine, and no added base, Lewis acid, or other catalyst.
A new route to protected acyloins and their enzymatic resolution with lipases
Scheid, Guenther,Kuit, Wouter,Ruijter, Eelco,Orru, Romano V. A.,Henke, Erik,Bornscheuer, Uwe,Wessjohann, Ludger A.
, p. 1063 - 1074 (2007/10/03)
A series of 16 different 3-acyloxy methyl ketones, the acyloin acetates and butyrates (±)-5, was synthesised by a straight-forward new method through alkylation of tert-butyl 2-acyloxyacetoacetates 3, followed by chemoselective dealkoxy-carbonylation of the tert-butyloxycarbonyl group in the presence of other ester groups. Subsequent hydrolysis of (±)-5 can be achieved with base to give racemic acyloins 6, or with lipase catalysis to afford the corresponding non-racemic acyloins (S)-6. The remaining (R)-acyloin esters 5 can be racemised and resubjected to the procedure, or hydrolysed chemically. The kinetic resolution with two of the six tested enzymes, CAL-B and BCL (PS) lipase, proceeded selectively [enantiomeric ratio (E) values between 50 and > 200] and most of the acyloins (S)-6 were obtained in very high enantiomeric excesses (up to > 99% ee). Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
Efficient microwave induced direct α-halogenation of carbonyl compounds
Lee, Jong Chan,Park, Jin Young,Yoon, So Young,Bae, Yong Hun,Lee, Seung Jun
, p. 191 - 193 (2007/10/03)
A novel and direct method for the synthesis of α-halocarbonyl compounds using sequential treatment of carbonyl compounds with [hydroxy(tosyloxy)iodo]benzene followed by magnesium halides under solvent-free microwave irradiation conditions is described.
