33458-07-0Relevant articles and documents
Dibromination of alkenes with LiBr and H2O2 under mild conditions
Martins, Nayara Silva,Alberto, Eduardo E.
, p. 161 - 167 (2018)
Electron-rich and electron-poor alkenes, and alkenes bearing protecting groups can be efficiently and stereoselectively converted to trans-dibromides using LiBr/H2O2 and AcOH as a proton source in 1,4-dioxane. For most substrates addition of 0.1 mol% of PhTeTePh enhances the reaction rate and the yield of the products. Experimental data suggest that the brominating agent prepared in situ is molecular bromine and that LiBr assists the activation of H2O2 allowing bromination to occur using AcOH as a mild proton source in uncatalyzed experiments. Scale-up is feasible: 10.0 mmol of 1-octene was quantitatively converted to 1,2-dibromooctene in one hour of reaction at room temperature.
Merging shuttle reactions and paired electrolysis for reversible vicinal dihalogenations
Dong, Xichang,Roeckl, Johannes L.,Waldvogel, Siegfried R.,Morandi, Bill
, (2021/02/12)
Vicinal dibromides and dichlorides are important commodity chemicals and indispensable synthetic intermediates in modern chemistry that are traditionally synthesized using hazardous elemental chlorine and bromine. Meanwhile, the environmental persistence of halogenated pollutants necessitates improved approaches to accelerate their remediation. Here, we introduce an electrochemically assisted shuttle (e-shuttle) paradigm for the facile and scalable interconversion of alkenes and vicinal dihalides, a class of reactions that can be used both to synthesize useful dihalogenated molecules from simple alkenes and to recycle waste material through retro-dihalogenation. The reaction is demonstrated using 1,2-dibromoethane, as well as 1,1,1,2-tetrachloroethane or 1,2-dichloroethane, to dibrominate or dichlorinate, respectively, a wide range of alkenes in a simple setup with inexpensive graphite electrodes. Conversely, the hexachlorinated persistent pollutant lindane could be fully dechlorinated to benzene in soil samples using simple alkene acceptors.
Electrosynthesis of N-unsubstituted enaminosulfones from vinyl azides and sodium sulfinates mediated by NH4I
Mulina, Olga M.,Doronin, Mikhail M.,Terent'ev, Alexander O.
supporting information, (2021/10/16)
A wide range of N-unsubstituted enaminosulfones were obtained via electrochemical sulfonylation of vinyl azides with sulfonyl radicals generated from sodium sulfinates. The discovery of N-unsubstituted enaminosulfones synthesis is based on a unique ability of the azido group to eliminate the N2 molecule. The process is performed under constant current conditions in an experimentally convenient undivided electrochemical cell equipped with a graphite anode and a stainless steel cathode applying NH4I both as the redox catalyst and the supporting electrolyte.
Electrochemical Synthesis of O-Phthalimide Oximes from α-Azido Styrenes via Radical Sequence: Generation, Addition and Recombination of Imide-N-Oxyl and Iminyl Radicals with C?O/N?O Bonds Formation
Paveliev, Stanislav A.,Churakov, Artem I.,Alimkhanova, Liliya S.,Segida, Oleg O.,Nikishin, Gennady I.,Terent'ev, Alexander O.
supporting information, p. 3864 - 3871 (2020/07/30)
Electrochemically induced radical-initiated reaction of vinyl azides with N-hydroxyphthalimide resulting O-phthalimide oximes with challenging for organic chemistry N?O-N fragment has been discovered. The developed approach introduces in synthesis electrochemically generated O-centered imide-N-oxyl radicals as the coupling components. Sequential formation of C?O and N?O bonds was achieved via generation and selective addition of imide-N-oxyl radicals, followed by recombination with iminyl radicals. A wide range of O-phthalimide oximes was obtained with the yields up to 84percent. (Figure presented.).
Rh(III)-Catalyzed C-H Activation-Initiated Directed Cyclopropanation of Allylic Alcohols
Phipps, Erik J. T.,Rovis, Tomislav
supporting information, (2019/05/06)
We have developed a Rh(III)-catalyzed diastereoselective [2+1] annulation onto allylic alcohols initiated by alkenyl C-H activation of N-enoxyphthalimides to furnish substituted cyclopropyl-ketones. Notably, the traceless oxyphthalimide handle serves three functions: directing C-H activation, oxidation of Rh(III), and, collectively with the allylic alcohol, in directing cyclopropanation to control diastereoselectivity. Allylic alcohols are shown to be highly reactive olefin coupling partners leading to a directed diastereoselective cyclopropanation reaction, providing products not accessible by other routes.
Rh(III)-Catalyzed C-H Activation-Initiated Directed Cyclopropanation of Allylic Alcohols
Phipps, Erik J.T.,Rovis, Tomislav
supporting information, p. 6807 - 6811 (2019/05/10)
We have developed a Rh(III)-catalyzed diastereoselective [2+1] annulation onto allylic alcohols initiated by alkenyl C-H activation of N-enoxyphthalimides to furnish substituted cyclopropyl-ketones. Notably, the traceless oxyphthalimide handle serves three functions: Directing C-H activation, oxidation of Rh(III), and, collectively with the allylic alcohol, in directing cyclopropanation to control diastereoselectivity. Allylic alcohols are shown to be highly reactive olefin coupling partners leading to a directed diastereoselective cyclopropanation reaction, providing products not accessible by other routes.
Visible-Light-Induced Regioselective C(sp3)-H Acyloxylation of Aryl-2 H-azirines with (Diacetoxy)iodobenzene
De, Aramita,Santra, Sougata,Hajra, Alakananda,Zyryanov, Grigory V.,Majee, Adinath
supporting information, p. 11735 - 11740 (2019/10/02)
A visible-light-promoted regioselective coupling of C(sp3)-H of aryl-2H-azirine and (diacetoxy)iodobenzene has been reported. Rose Bengal as an organophotoredox catalyst has been used in this reaction. The reaction proceeds under aerobic condition at room temperature. A variety of aryl-2H-azirines gives the corresponding acyloxylated azirines under this reaction conditions. The reaction goes through a radical pathway. The protocol is also applicable on gram-scale synthesis.
Rhodium(III)-Catalyzed Cyclopropanation of Unactivated Olefins Initiated by C-H Activation
Phipps, Erik J. T.,Piou, Tiffany,Rovis, Tomislav
supporting information, p. 1787 - 1790 (2019/09/09)
We have developed a rhodium(III)-catalyzed cyclopropanation of unactivated olefins initiated by an alkenyl C-H activation. A variety of 1,1-disubstituted olefins undergo efficient cyclopropanation with a slight excess of alkene stoichiometry. A series of mechanistic interrogations implicate a metal carbene as an intermediate.
Method for synthesizing alpha,beta-dibromide
-
Paragraph 0040; 0041; 0042, (2018/04/01)
The invention discloses a method for synthesizing alpha,beta-dibromide. The method is characterized in that a styrene compound as shown in the formula I is taken as a raw material, Zn-Al hydrotalciteZnAl-BrO3-LDHs of a bromate intercalation is taken as
Intermolecular Carboamination of Unactivated Alkenes
Zhang, Yu,Liu, Haidong,Tang, Luning,Tang, Hai-Jun,Wang, Lu,Zhu, Chuan,Feng, Chao
supporting information, p. 10695 - 10699 (2018/09/06)
Herein, we report the first example of group transfer radical addition of O-vinylhydroxylamine derivatives onto unactivated alkenes. By utilizing O-vinylhydroxylamine derivatives as both the N- and C-donors, this reaction enables intermolecular carboamination of unactivated alkenes in an atom economical fashion. As the process is initiated through N-radical addition followed by C-transfer, linear carboamination products are afforded. This differs from canonical radical carbofunctionalization of olefins, which typically favors branched product owing to initiation by C-radical addition.
