33695-47-5Relevant academic research and scientific papers
Acridine Orange Hemi(Zinc Chloride) Salt as a Lewis Acid-Photoredox Hybrid Catalyst for the Generation of α-Carbonyl Radicals
Das, Sanju,De Sarkar, Suman,Mandal, Tanumoy
supporting information, (2021/12/10)
A readily accessible organic-inorganic hybrid catalyst is reported for the reductive fragmentation of α-halocarbonyl compounds. The robust hybrid catalyst is a self-stabilizing combination of ZnCl2 Lewis acid and acridine orange as the photoactive organic dye. Mechanistic specifics of this hybrid catalyst have been studied in detail using both photophysical and electrochemical experiments. A systematic study enabled the discovery of the appropriate Lewis acid for the effective LUMO stabilization of α-halocarbonyl compounds and thereby lowering of reduction potential within the range of a standard organic dye. This strategy resolves the issues like dehalogenative hydrogenation or homo-coupling of alkyl radicals by guiding the photoredox cycle through an oxidative quenching pathway. The cooperativity between the photoactive organic dye and the Lewis acid counterparts empowers functionalization with a wide range of coupling partners through efficient and controlled generation of alkyl radicals and serves as an appropriate alternative to the expensive late transition metal-based photocatalysts. To demonstrate the application potential of this cooperative catalytic system, four different synthetic transformations of α-carbonyl bromides were explored with broad substrate scopes.
Methyl Radical Initiated Kharasch and Related Reactions
Tappin, Nicholas D. C.,Renaud, Philippe
supporting information, p. 275 - 282 (2020/12/07)
An improved procedure to run halogen atom and related chalcogen group transfer radical additions is reported. The procedure relies on the thermal decomposition of di-tert-butylhyponitrite (DTBHN), a safer alternative to the explosive diacetyl peroxide, to produce highly reactive methyl radicals that can initiate the chain process. This mode of initiation generates byproducts that are either gaseous (N2) or volatile (acetone and methyl halide) thereby facilitating greatly product purification by either flash column chromatography or distillation. In addition, remarkably simple and mild reaction conditions (refluxing EtOAc during 30 minutes under normal atmosphere) and a low excess of the radical precursor reagent (2 equivalents) make this protocol particularly attractive for preparative synthetic applications. This initiation procedure has been demonstrated with a broad scope since it works efficiently to add a range of electrophilic radicals generated from iodides, bromides, selenides and xanthates over a range of unactivated terminal alkenes. A diverse set of radical trap substrates exemplifies a broad functional group tolerance. Finally, di-tert-butyl peroxyoxalate (DTBPO) is also demonstrated as alternative source of tert-butoxyl radicals to initiate these reactions under identical conditions which gives gaseous by-products (CO2). (Figure presented.).
Rhodium-Catalyzed Carbene Transfer Reactions for Sigmatropic Rearrangement Reactions of Selenium Ylides
Jana, Sripati,Koenigs, Rene M.
, p. 3653 - 3657 (2019/05/24)
The rearrangement of selenium ylides is even today almost unexplored, although it would provide access to important organoselenium compounds with broad downstream applications. In this report, the first systematic study of sigmatropic rearrangement reactions of selenium ylides using a simple rhodium catalyst with catalyst loadings as low as 0.01 mol % is described. Selenium oxide pyrolysis of the rearrangement products gives access to important 1,1-disubstituted butadienes.
Synthesis of novel selenium and tellurium-containing tetrazoles: A class of chalcogen compounds with antifungal activity
Libero, Francieli M.,Xavier, Maurício C.D.,Victoria, Francine N.,Nascente, Patrícia S.,Savegnago, Lucielli,Perin, Gelson,Alves, Diego
scheme or table, p. 3091 - 3094 (2012/07/27)
We describe herein the synthesis and antifungal activity of new 5-arylchalcogenoalkyl-1H-tetrazoles 4. Arylchalcogenoalkyl-1H-tetrazoles 4 have been synthesized in high yields by reaction of arylchalcogenolate anions with chloronitriles 2, and subsequent
A novel synthesis of unsymmetrical selenides via the cleavage of Se-Se bond by Sm/cat.CoCl2 system
Chen, Rener,Su, Weike,Zhong, Weihui
, p. 620 - 621 (2007/10/03)
Promoted by Sm/cat. CoCl2 system, the Se-Se bond of diaryldiselenides was easily cleaved to form a "living" intermediate, which reacted readily with alkyl halides to afford unsymmetrical alkylarylselenides in good yields under mild and neutral reaction conditions.
Reductive cleavage of Se-Se bond by Sm/NiCl2 or Sm/NiCl 2.6H2O system: A novel preparation of unsymmetrical aryl selenides
Chen,Su
, p. 958 - 959 (2007/10/03)
The Sm/NiCl2 or Sm/NiCl2.6H2O system promoted diarylselenides to react with alkyl halides to afford unsymmetrical aryl selenides in good yields under mild and neutral conditions.
Fluorinations of α-seleno carboxylic acid derivatives with hypervalent (difluoroiodo)toluene
Arrica, Maria A.,Wirth, Thomas
, p. 395 - 403 (2007/10/03)
A very efficient synthesis of (difluoroiodo)toluene avoiding the use of elemental chlorine and elemental fluorine is described. We have fluorinated a series of α-acceptor substituted selenides using (difluoroiodo)toluene. The reactions are usually very clean and under the reaction conditions no further oxidized products are observed. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.
Zinc-mediated cleavage of diselenides: A novel synthesis of unsymmetrical diorganyl selenides in aqueous media
Movassagh, Barahman,Shamsipoor, Mojgan
, p. 121 - 122 (2007/10/03)
A convenient synthetic method has been developed for the preparation of unsymmetrical selenides through a one-pot zinc-mediated reaction of diselenides and active organic halides in aqueous media.
General synthesis of alkyl phenyl selenides from organic halides mediated by zinc in aqueous medium
Bieber, Lothar W.,De Sá, Ana C.P.F.,Menezes, Paulo H.,Gon?alves, Simone M.C.
, p. 4597 - 4599 (2007/10/03)
Organic halides of different structural types react with diphenyl diselenide and zinc dust in aqueous medium to give alkyl phenyl selenides. Benzylic and allylic bromides, α-bromoesters, acids and ketones and some primary alkyl iodides produce high yields even under acidic conditions. Less reactive halides need basic medium. The reaction proceeds equally well in the presence of various unprotected functional groups. Control experiments support a SH2 mechanism via alkyl radicals.
Convenient one-pot synthesis of α-selenonitriles, α-selenoesters and asymmetrical selenides by a Sm/ZnCl2 system in DMF-H2O
Guo,Zheng,Zhang
, p. 160 - 161 (2007/10/03)
α-Selenonitriles, α-selenoesters, and asymmetrical selenides can be readily obtained from the one-pot reaction of diselenides and active organic halides by a Sm/ZnCl2 system in DMF-H2O.
