3019-20-3Relevant articles and documents
Regenerable Thiophenolic Radical-Trapping Antioxidants
Yan, Jiajie,Poon, Jia-Fei,Singh, Vijay P.,Gates, Paul,Engman, Lars
, p. 6162 - 6165 (2015)
Diphenyl disulfides carrying alkyltelluro groups in the o-, m-, and p-positions were prepared using ortho-lithiation and lithium halogen exchange reactions. The novel antioxidants showed only minimal inhibitory effect on the azo-initiated peroxidation of linoleic acid in chlorobenzene until reduced to the corresponding thiophenols by tris(2-carboxyethyl)phosphine (TCEP). The best in situ generated thiophenol (from 7c) under these conditions quenched peroxyl radicals more efficiently than α-tocopherol with an almost 3-fold increase in inhibition time.
Alkylation of Nitropyridines via Vicarious Nucleophilic Substitution
Antoniak, Damian,Barbasiewicz, Micha?
supporting information, (2022/01/20)
Electrophilic nitropyridines react with sulfonyl-stabilized carbanions to give products of C-H alkylation via vicarious nucleophilic substitution. The process consists of formation of the Meisenheimer-type adduct followed by base-induced β-elimination of the sulfinic acid (e.g., PhSO2H). Mechanistic studies reveal that in the latter step alkyl substituent and adjacent nitro group tend to planarize for effective stabilization of benzyl anion, and thus, adduct of hindered isopropyl carbanion remains stable toward elimination for steric reasons.
Novel and facile procedure for the synthesis of Ni(II) and Pd(II) PSCOP pincer complexes. Evaluation of their catalytic activity on C-S, C-Se and C-C cross coupling reactions
Valderrama-García, Bianca X.,Rufino-Felipe, Ernesto,Valdés, Hugo,Hernandez-Ortega, Simón,Aguilar-Castillo, Bethsy Adriana,Morales-Morales, David
, (2019/12/09)
A new and facile procedure for the synthesis of non-symmetric phosphinito-thiophosphinito PSCOP pincer complexes based on Ni(II) and Pd(II) was developed. The synthesis of the complexes was carried out in a single step, starting from 3,3-dihydroxydiphenyldisulfide. The Ni(II) complexes were tested as catalysts in C-S and C-Se coupling reactions, being the tBu derivative 3-Ni the one exhibiting the best performance in both transformations. In this case, the sterics of the substrates was studied, showing that higher steric hindrance leads to lower yields. Analogously, the Pd(II) complexes were used as catalyst in Suzuki-Miyaura couplings of para-substituted bromobenzenes and phenyl boronic acid, being the analogous tBu derivative complex 3-Pd the best catalysts for this process, exhibiting tolerance to a wide range of functional groups.
Palladium complex containing meta-position carborane triazole ligand and preparation method and application of palladium complex
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Paragraph 0041-0043, (2020/08/07)
The invention relates to a palladium complex containing a meta-position carborane triazole ligand and a preparation method and application of the palladium complex. The palladium complex is prepared by the following steps: (1) dropwise adding an n-BuLi solution into a meta-position carborane m-C2B10H12 solution, carrying out stirring and reacting, then adding 3-propargyl bromide for a reaction again, and after the reaction is finished, carrying out separating to obtain 1,3-dipropargyl meta-carborane; and (2) under the catalytic condition of a catalyst CuI, carrying out a reaction on 1,3-dipropargyl meta-carborane and aryl azide, then adding PdCl2 into a reaction system, continuing the reaction, and after the reaction is finished, carrying out separation to obtain the palladium complex containing the meta-carborane triazole ligand. Compared with the prior art, the preparation method provided by the invention is simple and green; the complex can efficiently catalyze a coupling reaction of mercaptan and halogenated hydrocarbon to synthesize thioether compounds; reaction conditions are mild, substrate universality is good, catalytic efficiency is high, and few byproducts are produced;and the catalyst has high stability and is not sensitive to air and water.
Iridium-Catalyzed ortho-C-H Borylation of Thioanisole Derivatives Using Bipyridine-Type Ligand
Kuninobu, Yoichiro,Naito, Morio,Torigoe, Takeru,Yamanaka, Masahiro,Zeng, Jialin
supporting information, (2020/05/08)
A simple iridium catalytic system was developed that allows for a variety of 2-borylthioanisoles to be easily synthesized via ortho-selective C-H borylation of thioanisole derivatives. Once introduced, boryl and methylthio groups were converted by palladium-catalyzed transformations. Density functional theory calculations revealed that weak interactions, such as hydrogen bonding between the C-H bond of the SCH3 group and the oxygen atom of the boryl ligand, control the ortho-selectivity.
A Robust Pd-Catalyzed C-S Cross-Coupling Process Enabled by Ball-Milling
Browne, Duncan L.,Jones, Andrew C.,Nicholson, William I.,Smallman, Harry R.
supporting information, p. 7433 - 7438 (2020/10/09)
An operationally simple mechanochemical C-S coupling of aryl halides with thiols has been developed. The reaction process operates under benchtop conditions without the requirement for a (dry) solvent, an inert atmosphere, or catalyst preactivation. The reaction is finished within 3 h. The reaction is demonstrated across a broad range of substrates; the inclusion of zinc metal has been found to be critical in some instances, especially for coupling of alkyl thiols.
Synthesis of Sulfonimidamides from Sulfenamides via an Alkoxy-amino-λ6-sulfanenitrile Intermediate
Briggs, Edward L.,Tota, Arianna,Colella, Marco,Degennaro, Leonardo,Luisi, Renzo,Bull, James A.
supporting information, p. 14303 - 14310 (2019/09/06)
Sulfonimidamides are intriguing new motifs for medicinal and agrochemistry, and provide attractive bioisosteres for sulfonamides. However, there remain few operationally simple methods for their preparation. Here, the synthesis of NH-sulfonimidamides is achieved directly from sulfenamides, themselves readily formed in one step from amines and disulfides. A highly chemoselective and one-pot NH and O transfer is developed, mediated by PhIO in iPrOH, using ammonium carbamate as the NH source, and in the presence of 1 equivalent of acetic acid. A wide range of functional groups are tolerated under the developed reaction conditions, which also enables the functionalization of the antidepressants desipramine and fluoxetine and the preparation of an aza analogue of the drug probenecid. The reaction is shown to proceed via different and concurrent mechanistic pathways, including the formation of novel S≡N sulfanenitrile species as intermediates. Several alkoxy-amino-λ6-sulfanenitriles are prepared with different alcohols, and shown to be alkylating agents to a range of nucleophiles.
SPS–Ni(II) pincer compounds of the type [Ni(phPS2)(P(C6H4-4-R)3)] Synthesis, characterization and catalytic evaluation in C–S cross-coupling reactions
Gómez-Benítez, Valente,Valdés, Hugo,Hernández-Ortega, Simón,Germán-Acacio, Juan Manuel,Morales-Morales, David
, p. 144 - 148 (2017/10/13)
The synthesis and characterization of a series of SPS–Ni(II) pincer complexes with different para-substituted triphenylphosphines has been performed. The molecular structure of [Ni(phPS2)(PPh3)] (1) (phPS2H2 = PhP(C6H4-2-SH)2, bis(phenyl-2-thiol)phenylphosphine) was unequivocally determined by single crystal X-ray diffraction analysis. The metal centre exhibited a slightly distorted square planar geometry. The complexes showed a high catalytic activity in the C–S cross-coupling reaction of both alkyl- and aryl-disulfides with iodobenzenes for the production of non-symmetric sulfides. In general, the different para-substituted triphenylphosphine ligands do not affect the catalytic performance of the SPS–Ni(II) complexes. However, activity of the catalyst decreases with the steric hindrance of the different alkyl groups in the disulphide substrates.
CuI promoted sulfenylation of organozinc reagents with arylsulfonyl chlorides
Fu, Ying,Su, Yuhu,Xu, Qin-Shan,Du, Zhengyin,Hu, Yulai,Wang, Ke-Hu,Huang, Danfeng
, p. 6018 - 6022 (2017/02/05)
A CuI promoted sulfenylation of organozinc reagents with arylsulfonyl chlorides/PPh3 has been explored. This reaction proceeded smoothly through an alkyl/aryl radical (generated from organometallics) under mild conditions and produced the desired sulfide products in excellent yields.
Fundamental Difference in Reductive Lithiations with Preformed Radical Anions versus Catalytic Aromatic Electron-Transfer Agents: N,N-Dimethylaniline as an Advantageous Catalyst
Kennedy, Nicole,Liu, Peng,Cohen, Theodore
supporting information, p. 383 - 386 (2016/01/25)
The reductive lithiation of phenyl thioethers, or alkyl chlorides, by either preformed aromatic radical anions or by lithium metal and an aromatic electron-transfer catalyst, is commonly used to prepare organolithiums. Revealed herein is that these two methods are fundamentally different. Reductions with radical anions occur in solution, whereas the catalytic reaction occurs on the surface of lithium, which is constantly reactivated by the catalyst, an unconventional catalyst function. The order of relative reactivity is reversed in the two methods as the dominating factor switches from electronic to steric effects of the alkyl substituent. A catalytic amount of N,N-dimethylaniline (DMA) and Li ribbon can achieve reductive lithiation. DMA is significantly cheaper than alternative catalysts, and conveniently, the Li ribbon does not require the removal of the oxide coating when DMA is used as the catalyst.
