16536-57-5Relevant articles and documents
Use of Organic Molecules as Mechanistic Probes for Semiconductor-Mediated Photoelectrochemical Oxidations: Bromide Oxidation
Fox, Marye Anne,Pettit, Thomas L.
, p. 5013 - 5015 (1985)
Cyclohexene has been used as an organic probe for mechanism in the semiconductor-photocatalyzed oxidation of bromide in acetonitrile.Products derived from bromine addition and from cyclohexenyl radical mediated autoxidation were isolated.These results implicate a mechanism in which the photoexcited semiconductor effects a one electron oxidation of adsorbed bromide, producing surface-bound bromine atoms.These potentially could abstract hydrogen from cyclohexene to initiate autoxidation or could migrate along the semiconductor surface, producing bromine (Br2), which migrates into solution where it is rapidly trapped in conventional electrophilic addition.
Dendrimeric organochalcogen catalysts for the activation of hydrogen peroxide: Origins of the "dendrimer effect" with catalysts terminating in phenylseleno groups
Drake, Michael D.,Bright, Frank V.,Detty, Michael R.
, p. 12558 - 12566 (2003)
Several scenarios were evaluated to explain the large "dendrimer effect" observed in the bromination of cyclohexene with H2O 2 and NaBr catalyzed by the addition of Frechet-type dendrimers terminating in -O(CH2)3SePh groups. Although phenylseleninic acid was an efficient catalyst for the oxidation of NaBr with H2O2, first-order rate constants for the selenoxide elimination were too small to produce PhSeO2H at a rate sufficient to explain the rates of catalysis and no dendrimer effect was observed in the rates of selenoxide elimination. An induction period was observed using 1-SePh as a catalyst for the oxidation of Br- with H2O2. The addition of preformed selenoxide 1-Se(=O)Ph gave immediate catalysis with no induction period. However, rates of oxidation of the selenides with H 2O2 under homogeneous or biphasic conditions or with t-BuOOH under homogeneous conditions were too slow to account for the rates of catalysis, and no dendrimer effect was observed in the rates of oxidation. The primary oxidant for converting selenides to selenoxides was "Br+" produced initially by the uncatalyzed background reaction of H2O 2 with NaBr and then produced catalytically following formation of selenoxide groups. Autocatalysis is observed, and the rate of oxidation increases with the number of SePh groups. Autocatalysis is the source of the large dendrimer effect observed with the SePh series of catalysts.
SURFACTANT CONTROL OF BROMINATION PRODUCTS
Bianchi, M. T.,Cerichelli, G.,Mancini, G.,Marinelli, F.
, p. 5205 - 5208 (1984)
The product distribution in the bromination of cyclohexene is almost completely controlled by the addition order of the reactants to the surfactant, the obtained bromohydrin being 99percent pure.Water seems to be present all around the micelles head groups.
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.
Catalytic Asymmetric Bromination of Unfunctionalized Olefins with H2O as a Nucleophile
Zhang, Xun,Li, Jing,Tian, Hua,Shi, Yian
, p. 11658 - 11663 (2015/08/18)
The dimeric cinchona alkaloid (DHQD)2PHAL is used to catalyze an effective asymmetric bromohydroxylation of unfunctionalized olefins with H2O as nucleophile an N-bromobenzamide as a bromine source. A variety of optically active bromohydrins are formed with up to 88%ee. PHAL's positive: An effective asymmetric bromohydroxylation of unfunctionalized olefins with H2O as nucleophile catalyzed by the dimeric cinchona alkaloid (DHQD)2PHAL (see scheme) is described. Optically active bromohydrins are obtained with up to 88%ee.
Synthesis of Di-, Tri-, and tetrasubstituted oxetanes by rhodium-catalyzed O-H insertion and C-C bond-forming cyclization
Davis, Owen A.,Bull, James A.
supporting information, p. 14230 - 14234 (2015/02/19)
Oxetanes offer exciting potential as structural motifs and intermediates in drug discovery and materials science. Here an efficient strategy for the synthesis of oxetane rings incorporating pendant functional groups is described. A wide variety of oxetane 2,2-dicarboxylates were accessed in high yields, including functionalized 3-/4-aryl-and alkyl-substituted oxetanes and fused oxetane bicycles. Enantioenriched alcohols provided enantioenriched oxetanes with complete retention of configuration. The oxetane products were further derivatized, while the ring was maintained intact, thus highlighting their potential as building blocks for medicinal chemistry.
