34372-24-2Relevant academic research and scientific papers
Photogeneration of thiyl radicals using metal-halide perovskite for highly efficient synthesis of thioethers
Liu, Xin,Bai, Rong,Guo, Zhifen,Che, Yan,Guo, Chunyi,Xing, Hongzhu
, (2021/11/01)
Recently, the use of metal-halide perovskite (MHP) for photoinduced organics transformation has attracted much attention. We report herein the development of photoinduced thiol-ene reaction using inorganic MHP of CsPbBr3 nanocrystal that is visible light-responsive, easy-to-prepare, and cost-effective. Under blue light-emitting diode (LED), a series of thiol substrates are demonstrated to be highly efficient reaction partners to couple with alkenes tolerated with various functional groups, affording diverse thioethers containing C–S bonds. The CsPbBr3-mediated thiol-ene reaction is characterized by high efficiency, broad substrate applicability, excellent yields, and mild conditions. Mechanism investigation shows that the visible light-excited CsPbBr3 induces the generation of thiyl radicals via hole oxidation to initiate the reaction, followed by redox neutral pathway and/or chain transfer pathway to accomplish thiol–olefin coupling. It is notable that CsPbBr3 exhibits advanced thiol-ene performance than that using MHP analogs and others. The work presents a new exploration of MHP-mediated transformation and shows great potential of MHPs for radical chemistry.
Photoactive Metal-Organic Frameworks for the Selective Synthesis of Thioethers: Coupled with Phosphine to Modulate Thiyl Radical Generation
Guo, Zhifen,Liu, Xin,Bai, Rong,Che, Yan,Chi, Yanhong,Guo, Chunyi,Xing, Hongzhu
supporting information, p. 8672 - 8681 (2021/06/28)
Metal-organic framework (MOF) materials are intriguing photocatalysts to trigger radical-mediated chemical transformations. We report herein the synthesis and characterization of a series of isomorphic MOFs which show a novel structure, wide visible-light absorption, high chemical stability, and specific redox potential. The prepared MOFs were explored for the photoinduced single-electron oxidation of thiol compounds, generating reactive thiyl radicals to afford thioethers via a convenient thiol-olefin reaction. Importantly, we provide a widely applicable strategy by combing a photoactive MOF with phosphine to modulate the generation of thiyl radical in the reaction, thereby producing a single product of the thioether without the formation of a disulfide byproduct due to the dimerization of thiyl radicals. The photocatalytic reaction takes advantage of this strategy, showing great generality where tens of thiols and olefins have been examined as coupling partners. In addition, the strategy has also been demonstrated to be effective for the reactions catalyzed by other MOFs. Mechanism studies reveal that the selective synthesis of C-S products relies on a synergy between the photoinduced generation of a thiyl radical over the MOF and the in situ cleavage of S-S bond into a S-H bond by phosphine. It is notable that the synthesized MOFs show advanced performance in comparison with classical MOFs. The work not only provides a series of novel MOF photocatalysts that are capable of photoinduced thiol-olefin coupling but also indicates the great potential of MOFs for photochemical transformations mediated by reactive radicals.
Zinc-catalyzed regioselective addition of alkyl thiols to alkenes via anion or radical reactions
Taniguchi, Nobukazu
, p. 125 - 137 (2021/03/17)
Zn-catalyzed reactions of alkenes with alkyl thiols could afford alkyl sulfides regioselectively. When the ZnI2- catalyzed hydrothiolation of alkenes was achieved using alkyl thiols at 100 °C, Markovnikov-type alkyl sulfides were obtained in excellent yields without the formation of linear products. To the contrary, Zn(OAc)2- catalyzed reaction gave rise only to anti-Markovnikov-type products regioselectively. The reaction proceeded via a radical process.
KO-t-Bu Catalyzed Thiolation of β-(Hetero)arylethyl Ethers via MeOH Elimination/hydrothiolation
Shigeno, Masanori,Shishido, Yoshiteru,Hayashi, Kazutoshi,Nozawa-Kumada, Kanako,Kondo, Yoshinori
supporting information, p. 3932 - 3935 (2021/08/24)
Herein, we describe a KO-t-Bu catalyzed thiolation of β-(hetero)arylethyl ethers through MeOH elimination to form (hetero)arylalkenes followed by anti-Markovnikov hydrothiolation to afford linear thioethers. The system works well with a variety of β-(hetero)arylethyl ethers, including electron-deficient, electron-neutral, electron-rich, and branched substrates and a range of aliphatic and aromatic thiols.
Zirconium-catalysed direct substitution of alcohols: enhancing the selectivity by kinetic analysis
Camaj, David,Carlsson, Robin,Dalla-Santa, Oscar,Lill, Malin,Lundberg, Helena,Margarita, Cristiana,Ramstr?m, Anja,Tu?on, Hernando,Villo, Piret
, p. 7420 - 7430 (2021/11/23)
Kinetic analysis was used as a tool for rational optimization of a catalytic, direct substitution of alcohols to enable the selective formation of unsymmetrical ethers, thioethers, and Friedel-Crafts alkylation products using a moisture-tolerant and commercially available zirconium complex (2 to 8 mol%). Operating in air and in the absence of dehydration techniques, the protocol furnished a variety of products in high yields, including glycosylated alcohols and sterically hindered ethers. In addition, the kinetic studies provided mechanistic insight into the network of parallel transformations that take place in the reaction, and helped to elucidate the nature of the operating catalyst.
Photochemical Functionalization of Heterocycles with EBX Reagents: C?H Alkynylation versus Deconstructive Ring Cleavage**
Voutyritsa, Errika,Garreau, Marion,Kokotou, Maroula G.,Triandafillidi, Ierasia,Waser, Jér?me,Kokotos, Christoforos G.
supporting information, p. 14453 - 14460 (2020/10/12)
The development of novel methodologies for the functionalization of saturated heterocycles is highly desirable. Herein, we report a cheap and efficient photochemical method for the C?H functionalization of saturated O-heterocycles, as well as the deconstructive ring-cleavage of S-heterocycles, employing hypervalent iodine alkynylation reagents (ethynylbenziodoxolones, EBX). This photochemical alkynylation is performed utilizing phenylglyoxylic acid as the photoinitiator, leading to the corresponding products in good to high yields, under household fluorescent light bulb irradiation. When O-heterocycles were employed, the expected α-C?H alkynylation took place. In contrast, oxidative ring-opening to form a thioalkyne and an aldehyde was observed with S-heterocycles. Preliminary mechanistic experiments are presented to give first insights into this puzzling divergent reactivity.
Facile Thiol–Ene Click Protocol Using Benzil as Sensitizer and White LED as Light Source
Das, Anupam,Thomas, K. R. Justin
supporting information, p. 7214 - 7218 (2020/11/30)
The thiol–ene reaction leading to a series of thioether derivatives by simple metal and oxidant free visible light promoted photosensitized protocol, following anti-Markonikov hydrothiolation of unactivated aryl and alkyl olefins at room temperature is demonstrated. Benzil served as a green photosensitizer in this reaction and white LED lights as a light source. This radical based thiol–ene reaction is operationally simple and tolerates a wide variety of functional groups present in olefins.
Palladium-Catalyzed Enantioselective Thiocarbonylation of Styrenes
Wang, Xihong,Wang, Bing,Yin, Xuemei,Yu, Wangzhi,Liao, Yang,Ye, Jialin,Wang, Min,Hu, Lianrui,Liao, Jian
supporting information, p. 12264 - 12270 (2019/08/01)
A highly enantioselective thiocarbonylation of styrenes with CO and thiols has been achieved by Pd catalysis, providing highly enantioenriched thioesters in good to excellent yields. Key to the successful execution of this reaction is the use of a chiral sulfoxide-(P-dialkyl)-phosphine (SOP) ligands. This thiocarbonylation proceeds smoothly under mild reaction conditions (1 atm CO and 0 °C) and displays broad substrate scope. Also demonstrated is that this transformation can be conducted using surrogates of CO, greatly increasing the safety aspects of running the reaction. The generality and utility of the method is manifested by its application to the synthetic transformations of thioester products and the direct acylation of cysteine-containing dipeptides. A primary mechanism was investigated and a plausible catalytic cycle was proposed.
Metal-free photocatalytic thiol-ene/thiol-yne reactions
Kaur, Sarbjeet,Zhao, Gaoyuan,Busch, Evan,Wang, Ting
supporting information, p. 1955 - 1961 (2019/02/20)
The organic photocatalyst (9-mesityl-10-methylacridinum tetrafluoroborate) in the presence of visible light is used to initiate thiol-ene and thiol-yne reactions. Thiyl radicals are generated upon quenching the photoexcited catalyst with a range of thiols
Nanolayered cobalt-molybdenum sulphides (Co-Mo-S) catalyse borrowing hydrogen C-S bond formation reactions of thiols or H2S with alcohols
Corma, Avelino,Sorribes, Iván
, p. 3130 - 3142 (2019/03/13)
Nanolayered cobalt-molybdenum sulphide (Co-Mo-S) materials have been established as excellent catalysts for C-S bond construction. These catalysts allow for the preparation of a broad range of thioethers in good to excellent yields from structurally diverse thiols and readily available primary as well as secondary alcohols. Chemoselectivity in the presence of sensitive groups such as double bonds, nitriles, carboxylic esters and halogens has been demonstrated. It is also shown that the reaction takes place through a hydrogen-autotransfer (borrowing hydrogen) mechanism that involves Co-Mo-S-mediated dehydrogenation and hydrogenation reactions. A novel catalytic protocol based on the thioetherification of alcohols with hydrogen sulphide (H2S) to furnish symmetrical thioethers has also been developed using these earth-abundant metal-based sulphide catalysts.
