875-73-0Relevant academic research and scientific papers
TEMPO-Regulated Regio- and Stereoselective Cross-Dihalogenation with Dual Electrophilic X+ Reagents
Kong, Yi,Cao, Tongxiang,Zhu, Shifa
, 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.
Decarboxylative Tribromination for the Selective Synthesis of Tribromomethyl Ketone and Tribromovinyl Derivatives
Jayaraman, Aravindan,Cho, Eunjeong,Kim, Jimin,Lee, Sunwoo
, p. 3978 - 3989 (2018/09/21)
Tribromomethyl ketone and tribromovinyl derivatives were selectively prepared from the decarboxylative tribromination. The reaction between propiolic acid derivatives and dibromoisocyanuric acid (DBCA)/H2O afforded predominantly a tribromomethyl ketone derivative in the presence of AgOAc (10 mol%). When the same reaction was conducted with 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) instead of AgOAc, tribromovinyl derivatives were exclusively formed in good yields. It was found that ethynyl bromide is an intermediate. (Figure presented.).
Preparation of 1-aryl-2-bromo-3,3-difluorocyclopropenes
Lin, Shaw-Tao,Chen, Li-Chwen,Lee, Chun-Jen
, p. 353 - 355 (2007/10/03)
1-Aryl-2-bromo-3,3-difluorocyclopropanes were prepared from the reaction of 2′,2′-difluorostyrene and dibromocarbene instead of from 1-aryl-2-haloacetylenes and difluorocarbene. These results are rationalised by the energy gap between HOMO(styrene), HOMO(acetylene) and LUMO(CX2). The title compounds were converted to methyl arylpropynoate in MeOH solution in quantitative yield.
Synthesis and structure of α,β-Dibromo-β-nitrostyrenes
Berestovitskaya,Bel'skii,Macmillan,Makarenko,Trukhin
, p. 803 - 808 (2007/10/03)
A procedure was developed for preparing a new type of halonitroethenes, 1,2-dibromo-1-nitro-2-pnenyl-and -2-(p-chlorophenyl)ethenes; the energies and geometries of their molecules were calculated. The bond lengths, bond angles, and torsion angles in the f
Facile preparation of the methyl acetal of methyl phenylglyoxylate
Bovonsombat,McNelis
, p. 2361 - 2365 (2007/10/02)
The methyl acetal of methyl phenylglyoxylate has been prepared from halophenylethynes, N-iodosuccinimide and catalytic amounts of (hydroxy(p-tosyloxy)iodo)benzene or p-toluenesulfonic acid in methanol at room temperature.
1,1,2-Trihaloalkenes and Dimeric Acetylenes from Acetylenic Tellurium Species
Dabdoub, Miguel J.,Comasseto, Joao V.,Barros, Simone M.,Moussa, Fauzi
, p. 2181 - 2183 (2007/10/02)
Reaction of 1-telluroalk-1-ynes with bromine and iodine or with Cu(II) chloride furnishes respectively 1,1,2-trihaloalkenes and 1,4-disubstituted 1,3-diynes.
