5927-93-5Relevant academic research and scientific papers
Diastereoselective Synthesis of Cyclic sp 3 -Enriched cis -β-Alkoxysulfonyl Chlorides
Sokolov, Andriy,Golovach, Sergey,Kozlinsky, Ihor,Dolia, Krystyna,Tolmachev, Andrey A.,Kuchkovska, Yuliya,Grygorenko, Oleksandr O.
supporting information, p. 848 - 858 (2019/02/10)
A three-step synthesis of β-alkoxy-substituted alicyclic sulfonyl chlorides from cyclic alkenes and alcohols is reported. The scope of the method was studied for a range of the substrates with various steric and electronic properties. The title compounds were obtained on a hundred-gram scale in up to 52% overall yield scale as single cis -diastereomers.
A useful propionate cofactor enhancing activity for organic solvent-tolerant recombinant metal-free bromoperoxidase (perhydrolase) from Streptomyces aureofaciens
China, Hideyasu,Ogino, Hiroyasu
, p. 327 - 332 (2019/07/12)
The oxidative brominating activity of an organic solvent-tolerant recombinant metal-free bromoperoxidase BPO-A1 with C-terminal His-tag (rBPO-A1), from Streptomyces aureofaciens found to depend on various additives. These included carboxylic acids, used as cofactors and alcohols, used as water-miscible organic solvents. Enzyme activity was significantly enhanced by using propanoic acid (PA) as a cofactor, which had a high Log D at pH 5.0 and ethylene glycol with a low Log P. The positional specificity of oxidative hydroxybromination for olefins, using rBPO-A1 and PA in the presence of methanol, was higher compared to a non-enzymatic reaction using peracetic acid. The oxidative bromination step, occurring after enzymatic peroxidation step, is suggested to be pseudoenzymatic.
Alkoxybromination of olefins using ammonium bromide and oxone
Kumar, Macharla Arun,Naresh, Mameda,Rohitha, Chozhiyath Nappunni,Narender, Nama
supporting information, p. 3121 - 3129 (2014/01/06)
A mild, efficient, and highly regio- and stereoselective method for the methoxy and ethoxy bromination of olefins has been developed using NH 4Br as a bromine source and Oxone as an oxidant. Various kinds of olefins (aromatic, linear, and cyclic olefins) afforded the corresponding alkoxy brominated products in moderate to excellent yields. Taylor & Francis Group, LLC.
A regioselective and stereoselective methoxy bromination of olefins using diacetoxyiodobenzene and phenyltrimethyl ammoniumtribromide
Hangirgekar,Shirodkar
experimental part, p. 179 - 184 (2012/01/13)
A facile regio and stereoselective methoxy-bromination of alkenes using phenyltrimethyl ammoniumtribromide (PTAB) and (diacetoxyiodo) benzene (DIB) as oxidant has been carried out in the present investigation. The IR, NMR and LCMS of all the synthesized compounds have been used to characterize them.
Theoretical and infrared studies on the conformational isomerism of trans-2-bromo-alkoxycyclohexanes
Silla, Josue M.,Duarte, Claudimar J.,Freitas, Matheus P.,Ramalho, Teodorico C.,Cormanich, Rodrigo A.,Santos, Francisco P.,Tormena, Claudio F.,Rittner, Roberto
experimental part, p. 359 - 362 (2011/11/29)
The infrared spectra of trans-2-bromo-alkoxycyclohexanes (alcoxy = OMe, OEt, OiPr and OtBu) were obtained for the neat liquid, and the C-Br stretching mode was quantitatively analyzed to give insight about the conformational isomeris
Tribromoisocyanuric acid: A new reagent for regioselective cobromination of alkenes
De Almeida, Leonardo S.,Esteves, Pierre M.,De Mattos, Marcio C. S.
, p. 1515 - 1518 (2007/10/03)
A simple one-step method for the preparation of tribromoisocyanuric acid in good yield (87%) has been developed. The reaction of tribromoisocyanuric acid with alkenes in presence of nucleophilic solvents (MeOH, i-PrOH, AcOH and a mixture of H2O-acetone, 1:5) led to the corresponding β-bromoethers, β-bromoacetates and bromohydrins, in high regioselectivity and good yields (73-98%). Georg Thieme Verlag Stuttgart.
A simple and efficient method for regioselective and stereoselective synthesis of vicinal bromohydrins and alkoxybromides from an olefin
Phukan, Prodeep,Chakraborty, Pranita,Kataki, Dolly
, p. 7533 - 7537 (2007/10/03)
(Chemical Equation Presented) A very rapid and efficient method has been developed for the synthesis of vicinal bromohydrins and alkoxybromides directly from an olefin without any catalyst. The reaction was performed in CH 3CN-water (4:1) or alcohol using N,N-dibromo-p-toluenesulfonamide (TsNBr2) as the brominating agent. Excellent yields and regio- and stereoselectivities have been obtained. Bromohydrins are formed instantaneously, whereas formation of alkoxybromides takes 30-60 min.
Generation of interhalogen fluorides under mild conditions: A comparison of sluggish and reactive interhalogen fluorides
Shellhamer, Dale F.,Horney, Mark J.,Pettus, Benjamin J.,Pettus, Tobiah L.,Stringer, Joy Merry,Heasley, Victor L.,Syvret, Robert G.,Dobrolsky Jr., John M.
, p. 1094 - 1098 (2007/10/03)
Interhalogen fluorides (XF; X = I, Br, or Cl) generated from xenon difluoride (XeF2) or triethylamine trihydrofluoride (TREAT HF) with iodine (I2), N-halosuccinimides (NXS; X = I, Br, or Cl), or alkylhypohalites (ROX; R = CH3 or t-Bu, X = Br or Cl) with alkenes and aromatics are reported. A comparison of the above reactions with other methods reported in the literature to generate interhalogen fluorides is made. Interhalogens generated from direct action of elemental fluorine (F2) or XF3 (X = I, Br, or Cl) with chlorine (Cl2), bromine (Br2), or iodine (I2) give a species that can react with electron-deficient alkenes or aromatics. These reagents are too reactive for electron-rich substrates. Interhalogen fluorides from reagents like NXS or ROX with XeF2 or amine HF are much less reactive and give good yields with electron-rich akenes or aromatics.
Reversible Formation of Bromonium Ions. Preferential Reaction of Br(1-) on the Br(1+) of the Bromonium Ion Produced from the Solvolysis of the trans-2-Bromotriflate of Cyclohexane in MeOH or HOAc Containing Added Bromide
Zheng, C. Y.,Slebocka-Tilk, H.,Nagorski, R. W.,Alvarado, L.,Brown, R. S.
, p. 2122 - 2127 (2007/10/02)
The trans-2-bromotriflate of cyclohexane (4) has been solvolyzed at ambient temperatures in HOAc and MeOH containing varying and in the presence of 0.5M of a scavenger olefin, cyclopentene.The kinetics of solvolysis of 4 have been determined by observing the rate of change in color of an acid/base indicator that instantly responds to the production of HOTf or HBr.The kinetics show that the rate of solvolysis of 4 at constant ionic strength is independent of Br(1-).The products of solvolysis of 4 under the various conditions have been determined by quantitative GLPC analysis.In the presence of Br(1-), the products consisted of the trans 1,2-dibromides and bromosolvates of cyclohexane and cyclopentane.The cyclopentyl products are shown to be formed from the electrophilic addition of Br2/Br3(1-) to cyclopentene while trans-1,2-dibromocyclohexane (2) was obtained from Br(1-) capture of the bromonium ion of cyclohexene on carbon.The Br2 arises from capture by Br(1-) of the bromonium ion on Br(1+).On the basis of the ratio of the cyclopentyl products/2, Br(1-) capture of the solvolytically produced bromonium ion by attack on Br(1+) is 4-5 times more prevalent than attack on carbon in HOAc and ca. 25 times more prevalent than attack on carbon in MeOH.The results have strong implications on the reversal of bromonium ions formed during the electrophilic bromination of olefins in hydroxylic solvents.
Electrophilic addition of Br2 to olefins in the presence of nucleophilic trapping anions. Implications for the lifetimes of bromonium ion intermediates produced from electrophilic bromination of olefins in methanol
Nagorski,Brown
, p. 7773 - 7779 (2007/10/02)
The product ratios for Br2 or NBS additions to cyclopentene, cyclohexene, tetramethylethylene, and styrene in MeOH containing varying concentrations of added N3- or Br have been determined with an aim of determining the lifetimes of the bromonium ion intermediates. On the basis of the ratio of trans bromo azide to methoxy bromide products, the partitioning rate constant ratios (kN/kCH3OH) for the four olefins are 5.9, 4.9, 9.3, and 2.7 M-1, respectively. That the far better nucleophile (N3-) does not lead to a marked increase in product formation relative to solvent suggests that both species capture a highly reactive intermediate in a non-activation-limited process. Assuming that the N3- reacts with the intermediate with a diffusion-limited rate constant of 1010 M-1 s-1, the respective lifetimes of the ions produced from bromination of the four olefins are 5.9 × 10-10, 5.0 × 10-10, 9.3 × 10-10, and 2.7 × 10-10 s, respectively. On the basis of existing comparisons, these values indicate the following: the cyclic olefins produce ions that live about 100 times longer than a secondary carbocation; tetramethylethylene gives a bromonium ion that lives ～10 times longer than a tertiary cation; and styrene gives an ion (bromonium or β-bromo cation) that is ～40-fold longer lived than the 1-phenylethyl cation. In the case of Br2 or NBS addition to cyclohexene in the presence of varying [Br-], the ratio of the trans dibromide to methoxy bromide product tends to zero as [Br-] → 0. This indicates that the trans dibromide cannot be formed by ion pair collapse. The solvolysis of trans-2-bromocyclohexyl trifluoromethanesulfonate in MeOH containing N3- or Br produces significantly less azide or bromide capture product than does electrophilic addition of Br2 or NBS to cyclohexene under the same conditions, suggesting that the ions produced in the two cases are not identical.
