- Visible-Light-Promoted Polysubstituted Olefins Synthesis Involving Sulfur Ylides as Carbene Trapping Reagents
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A blue-light-emitting diode (LED) promoted coupling of aryl diazoacetates with sulfur ylides is described. This protocol features mild conditions, good functional group tolerance, and broad substrate scope for both aryl diazoacetates with sulfur ylides. Under optimal reaction conditions, a wide range of trisubstituted olefins is obtained in moderate to good yield, which can be further transferred to other biologically important heterocycles after a two-step simple operation.
- Ye, Cong,Cai, Bao-Gui,Lu, Juan,Cheng, Xiao,Li, Lei,Pan, Zhong-Wen,Xuan, Jun
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p. 1012 - 1022
(2021/01/09)
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- Synthesis of functionalized thietanes via electrophilic carbenoid-induced ring expansion of thiiranes with sulfonium acylmethylides as carbene precursors
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Various functionalized thietanes were prepared from thiiranes via an electrophilic ring expansion with rhodium carbenoids as electrophiles generated from safe and readily accessible dimethylsulfonium acylmethylides. The reaction appears to proceed through electrophilic metallocarbenoid-induced activation of thiiranes, nucleophilic ring-opening of the activated thiiranes with dimethyl sulfide as a transient nucleophile, and nucleophilically intramolecular cyclization. The Umpolung from the nucleophilic ylides to the electrophilic carbenoids plays an important role in both the activation and ring opening of thiiranes and subsequent cyclization. The current method provides a new strategy for the efficient preparation of functionalized thietanes from readily available thiiranes.
- Dong, Jun,Du, Hongguang,Xu, Jiaxi
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p. 10724 - 10739
(2019/09/30)
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- 1,6-Conjugated Addition-Mediated [2+1] Annulation: Approach to Spiro[2.5]octa-4,7-dien-6-one
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A formal 1,6-conjugated addition-mediated [2+1] annulation to synthesize spiro[2.5]octa-4,7-dien-6-one with p-quinone methides and sulfur ylides has been described. This domino-type process was highly diastereoselective and exhibited good functional group tolerance and scalability without the use of metals and bases.
- Yuan, Zhenbo,Fang, Xinxin,Li, Xuanyi,Wu, Jie,Yao, Hequan,Lin, Aijun
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p. 11123 - 11130
(2015/11/18)
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- Functionalized α-keto stabilized sulfonium ylides as highly active ligand precursors for palladium catalyzed Suzuki-Miyaura cross-couplings
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Five α-keto stabilized sulfonium ylides as type (Me) 2SCHC(O)C6H4-p-X (X = H, Br, NO2, CH3 and OCH3) {L1-L5} were used as ligand precursors in the Suzuki-Miyaura cross-coupling reaction. The best catalytic performance was obtained by using a sulfonium ylide/Pd ratio of 2:1. The catalytic systems displayed high activities, which increased in the order R = NO2 (L3) 2) 1) 3 (L4) 3 (L5). The coupling reactions proceeded smoothly with 0.05 mol% PdCl2 and 0.1 mol% L5 in DMF at 130 °C between varieties of electronically activated, deactivated and neutral aryl halides and aryl boronic acids within short reaction times and without the need for exclusion of air which gave good to high yields of the corresponding products. All the studied ligands demonstrated very high activity in the Suzuki-Miyaura cross-coupling, which yielded turnover numbers up to 1940. Comparative studies showed that the performance of sulfonium ylide L5 is significantly superior to that of related phosphine-free ligands.
- Sabounchei, Seyyed Javad,Hashemi, Ali
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p. 123 - 127
(2014/08/18)
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- Reactivity of mercury(II) halides with the α-keto stabilized sulfonium ylides: Crystal structures of two new polymer and binuclear complexes and in vitro antibacterial study
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Reaction of α-keto stabilized sulfonium ylides (Me) 2SCHC(O)C6H4R (R = p-NO2 (Y) and p-Br(Y′)) with HgX2 (X = Cl, Br and I) in equimolar ratios using methanol as solvent leads to two types of products. Single crystal X-ray diffraction analysis reveals (i) binuclear complex of [HgI2(Y)] 2 (3) with an asymmetric halide-bridged structure and (ii) one-dimensional polymer of [HgI2(Y′)]n (6) that the monomeric -Hg-I-Hg- bridging leads to a zig-zag polymeric chain in which mercury assumes a distorted tetrahedral geometry. Characterization of the compounds by IR, 1H and 13C NMR spectroscopy confirmed coordination of the ylide to the metal through the carbon atom. Analytical data indicate a 1:1 stoichiometry between the ylide and Hg(II) halide in all of products. The Hg(II) complexes with different ligands evaluated for their antibacterial activity using disc diffusion method. The results show that all complexes represent antibacterial activity against bacteria tested especially on Gram positive ones.
- Sabounchei, Seyyed Javad,Bagherjeri, Fateme Akhlaghi,Boskovic, Colette,Gable, Robert W.,Karamian, Roya,Asadbegy, Mostafa
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- Synthesis and characterization of novel simultaneous C and O-coordinated and nitrate-bridged complexes of silver(i) with carbonyl-stabilized sulfonium ylides and their antibacterial activities
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Reaction of sulfonium ylides (Me)2SCHC(O)C6H 4R (R = H; m-NO2; p-NO2; p-OMe; p-Me and p-Br) with AgNO3 in dichloromethane leads to various compounds. Single crystal X-ray diffraction analysis reveals that the adducts take 3 forms: (i) two-dimensional polymer, [AgNO3(Me2SCHC(O)C 6H5)]n (1), with nitrate bridges in which each nitrate coordinates to three silver atoms through two oxygen atoms and two Me2SCHC(O)C6H5 ligands coordinate to silver centers through carbon atoms; (ii) cationic binuclear, [Ag(Me 2SCHC(O)C6H4-m-NO2) 2]2(NO3)2·2H2O (2), in which Me2SCHC(O)C6H4-m-NO2 ligands simultaneously coordinate through both carbon and oxygen atoms with nitrate as a counter ion, and (iii) cationic mononuclear and anionic binuclear, [Ag(Me2SCHC(O)C6H4-p-NO2) 2]2[{AgNO3(μ-NO3) (Me 2SCHC(O)C6H4-p-NO2)} 2]·2CH3OH (3), in which nitrate groups act as bridging as well as terminal ligands, and Me2SCHC(O)C 6H4-p-NO2 ligands display C-coordination. Characterization of the obtained compounds was also performed by infrared, 1H- and 13C-NMR spectroscopy and analytical data indicated a 1:2 stoichiometry between the silver(i) nitrate and ylide p-OMe (4) and 1:1 for ylides p-Me (5) and p-Br (6). In addition, the antibacterial effects of DMSO-solutions of complexes 1-6 were evaluated by the agar disc diffusion method against three Gram positive and three Gram negative bacteria. All complexes displayed antibacterial activity against these bacteria, with high levels of inhibitory potency exhibited against the Gram negative species.
- Sabounchei, Seyyed Javad,Akhlaghi Bagherjeri, Fateme,Mozafari, Zeinab,Boskovic, Colette,Gable, Robert W.,Karamian, Roya,Asadbegy, Mostafa
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p. 2520 - 2529
(2013/04/10)
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- Unusual fluorescent properties of novel fluorophores, 6-aryl-3,4-diphenyl-α-pyrone derivatives
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Novel fluorophores, 6-aryl-3,4-diphenyl-α-pyrones, were synthesized and their spectroscopic properties investigated in the form of evaporated films on plain glass slides, as well as in the solid and solution states. An electron-donating aryl group on the 6-position of the pyrones causes a red-shift in the absorption and fluorescent maxima. In the solid states, they show intense blue-to-orange fluorescence, but not in solution. This unusual fluorescent property is caused by fixing the 6-aryl group of the pyrones, and is the result of molecular packing. These interactions induce a pathway for radiative decay, which is associated with intense fluorescence emission only in the solid state.
- Hirano,Minakata,Komatsu
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p. 1567 - 1575
(2007/10/03)
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