21875-72-9Relevant 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,Mandal, Tanumoy,De Sarkar, Suman
, p. 755 - 765 (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.
Preparation of Thioanisole Biscarbanion and C-H Lithiation/Annulation Reactions for the Access of Five-Membered Heterocycles
Zhu, Ranran,Liu, Zheyuan,Chen, Jie,Xiong, Xiaoyu,Wang, Yuntao,Huang, Lin,Bai, Jinshan,Dang, Yanfeng,Huang, Jianhui
supporting information, p. 3161 - 3165 (2018/06/11)
The synthesis, isolation, and X-ray structure of a thioanisole-based trilithium complex are reported. On the basis of the double-lithiation strategy, two novel synthetic methodologies have been developed under mild reaction conditions (room temperature): (1) reactions of lithiated thioanisoles with nitriles give benzoisothiazoles via a [3 + 2]-type of approach with two new bond formations and (2) formation of benzothiophenes from thioanisoles and amides through a [4 + 1] pattern forming 4 new chemical bonds.
A route to benzylic arylsulfoxides from β-ketosulfoxides
Chang, Meng-Yang,Cheng, Yu-Chieh,Chan, Chieh-Kai
, p. 4068 - 4075 (2016/07/06)
The K2CO3-mediated benzylation of β-ketosulfoxides 4 with 2.0?equiv of benzylic halides 5 affords benzylic arylsulfoxides 6 in moderate yields along with trace amounts of chalcones 7. The products 6 are assumed to form in situ intermediates of sulfenate anions from β-ketosulfoxides which are commonly involved in carbon–sulfur bond formation. A plausible mechanism has been proposed.
Visible light mediated reductions of ethers, amines and sulfides
Monos, Timothy M.,Magallanes, Gabriel,Sebren, Leanne J.,Stephenson, Corey R.J.
, p. 240 - 248 (2016/07/21)
Visible light-mediated photoredox catalysis enables the chemoselective reduction of activated carbon–heteroatom bonds as a function of reduction potential. The expansion of the scope of C–X bond reductions towards less activated motifs, such as ethers, amines and sulfides, is important to both organic synthesis and macromolecular degradation method development. In the present report, exploration of photoredox catalysis in alcoholic solvents mediated a decrease in the super-stoichiometric use of iPr2NEt and HCO2H in the reduction of α-keto ethers, amines and sulfides. Additionally, in the absence of fragmentation, [Formula presented] bond formation was afforded, suggesting an intermediate ketyl radicals are present in these transformations.
Catalyst-Free Insertion of Sulfoxonium Ylides into Aryl Thiols. A Direct Preparation of β-Keto Thioethers
Dias, Rafael M. P.,Burtoloso, Antonio C. B.
supporting information, p. 3034 - 3037 (2016/07/06)
Insertion of sulfoxonium ylides into the S-H bond of aryl thiols without the need for a catalyst is demonstrated, furnishing β-keto thioethers in excellent yield in most cases. The method overcomes traditional syntheses that employ metal catalysts in combination with diazo compounds or toxic and hard-prepared haloketones. The experimental setup consists of mixing the reagents in acetonitrile at room temperature. Additional experimental as well as kinetic isotopic effect studies give some insight into the mechanism of this reaction.
Rhodium-catalyzed organothio exchange reaction of α-organothioketones with disulfides
Arisawa, Mieko,Toriyama, Fumihiko,Yamaguchi, Masahiko
experimental part, p. 1349 - 1352 (2010/12/24)
RhH(PPh3)4 and 1,2-bis(diphenylphosphino)ethane (dppe) catalyzed the organothio exchange reaction of α-organothioketones and organic disulfides. The reaction was affected by the structure of the substrate: α-phenylthio and α-alkylthio aryl ketones reacted effectively with diaryl and dialkyl disulfides; α-phenylthio dialkyl ketones reacted with diaryl disulfides but not with dialkyl disulfides; diaryl disulfides with electron-donating p-substituents were more reactive than those with electron-withdrawing p-substituents.
Rhodium-catalyzed methylthio transfer reaction between ketone α-positions: Reversible single-bond metathesis of C-S and C-H bonds
Arisawa, Mieko,Suwa, Katsunori,Yamaguchi, Masahiko
supporting information; experimental part, p. 625 - 627 (2009/08/14)
(Chemical Equation Presented) In the presence of a catalytic amount of RhH(PPh3)4 and 1,2-bis(diphenylposphino)ethane (dppe), α-phenylthio ketones were methylthiolated with ρ-cyano-α- methylthioacetophenone giving α-phenylthio-α-meth
Ionic liquid promoted regio- and stereo-selective thiolysis of epoxides-A simple and green approach to β-hydroxy- and β-keto sulfides
Ranu, Brindaban C.,Mandal, Tanmay,Banerjee, Subhash,Dey, Suvendu S.
, p. 278 - 283 (2008/02/11)
A variety of epoxides underwent facile cleavage by thiols under the catalysis of 1-methyl-3-butylimidazolium bromide, [bmIm]Br, to produce the corresponding β-hydroxy sulfides with high regio- and stereo-selectivity. On the other hand, a specially designed basic ionic liquid, [bmIm]OH, efficiently catalyzes the thiolysis of ,β-epoxy ketones providing β-keto sulfides through simultaneous retro-aldol cleavages. The reactions are clean, high yielding, and do not require any organic solvent. The catalyst is also recycled. CSIRO 2007.
Indium triflate: A mild and efficient Lewis acid catalyst for O-H insertion reactions of α-diazo ketones
Muthusamy, Sengodagounder,Babu, Srinivasarao Arulananda,Gunanathan, Chidambaram
, p. 3133 - 3136 (2007/10/03)
Facile O-H insertion reactions of α-diazo ketones with aliphatic/aromatic alcohols or benzenethiol have been developed in the presence of indium triflate as a catalyst. These reactions provided good yields of α-alkoxy ketones. A comparative study with other Lewis acids establishes the reactivity of indium triflate in O-H insertion reactions of α-diazo ketones.
Elaboration of 1-benzoyltetrahydroisoquinoline derivatives employing a Pictet-Spengler cyclization with α-chloro-α-phenylthioketones. Synthesis of O-methylvelucryptine
Silveira, Claudio C,Bernardi, Carmem R.,Braga, Antonio L.,Kaufman, Teodoro S.
, p. 8947 - 8950 (2007/10/03)
The reaction of N-tosyl-β-phenethylamines with α-chloro-α-phenylthioketones, leading to 1-benzoyl- and 1-pivaloyl-tetrahydroisoquinolines under modified Pictet-Spengler conditions, is described. The synthesis of O-methylvelucryptine employing this transformation as a key step is reported.
