19598-15-3Relevant academic research and scientific papers
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.
Regio-and stereoselective hydroxybromination and dibromination of olefins using ammonium bromide and oxone
MacHarla, Arun Kumar,Chozhiyath Nappunni, Rohitha,Nama, Narender
supporting information; experimental part, p. 1401 - 1405 (2012/04/04)
An efficient protocol for the synthesis of vicinal bromohydrins and dibromides from olefins is presented. Various olefins are regio-and stereoselectively hydroxybrominated and dibrominated with anti fashion, following Markonikov's rule, using eco-friendly, non-toxic, and stable reagents such as NH4Br and oxone in CH3CN/H2O (1:1) and CH3CN without employing catalyst in moderate to excellent yields. Bromohydrins are formed instantaneously.
Mechanism of the enantioselective oxidation of racemic secondary alcohols catalyzed by chiral Mn(III)-salen complexes
Brown, M. Kevin,Blewett, Megan M.,Colombe, James R.,Corey
supporting information; experimental part, p. 11165 - 11170 (2010/10/03)
The experiments described here clarify the mechanism and origin of the enantioselectivity of the oxidation of racemic secondary alcohols catalyzed by chiral Mn(III)-salen complexes using HOBr, Br2/H2O/KOAc or PhI(OAc)2/H2O/KBr as a stoichiometric oxidant. Key points of the proposed pathway include (1) the formation of a Mn(V)-salen dibromide, (2) its subsequent reaction with the alcohol to give an alkoxy-Mn(V) species, and (3) carbonyl-forming elimination to produce the ketone via a highly organized transition state with intramolecular transfer of hydrogen from carbon to an oxygen of the salen ligand.
Electrophilic Additions to Indene and Indenone: Factors Effecting Syn Addition
Heasley, Gene E.,Bower, Timothy R.,Dougharty, Kent W.,Easdon, Jerome C.,Heasley, Victor L.,et al.
, p. 5150 - 5155 (2007/10/02)
The electrophiles bromine, bromine chloride, chlorine, acetyl hypochlorite, and acetyl hypobromite all yield substantial cis addition product by reaction with indene (1) in aprotic solvents, showing that the direct syn collapse of ion pairs obtained from bromine and similar electrophiles is readily possible.The cis to trans ratios with the halogens (but not with the acyl hypohalites) vary with solvent polarities.In the low-polarity solvents (hydrocarbons and carbon tetrachloride) much more syn addition occurs at high halogen concentration.Syn addition of the above electrophiles to 1 as well as methyl hypobromite and methyl hypochlorite was also observed in methanol and acetic acid, with the exception of bromination in methanol where only the trans-dibromide was obtained.Bromine and bromine chloride addition to indenone (20) yielded only the trans-dihalides, suggesting that a neighboring keto group stabilizes the bridged bromonium ion.Chlorination of 20 was not stereospecific but yielded more trans-dichloride than did chlorination of 1.
