- 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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- Binuclear mercury(II) complexes of sulfonium ylides: Synthesis, structural characterization and anti-bacterial activity
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Reaction of α-keto stabilized sulfonium ylides (Me) 2SCHC(O)C6H4R (R = p-Me (a); p-Cl (b)) with HgX2 (X = Cl, Br and I) in equimolar ratios using methanol as solvent leads to binuclear products of the type [HgX2(ylide)]2 (X = Cl (1), Br (2) and I (3)). Single crystal X-ray diffraction analysis reveals the presence of unexpected asymmetric halide-bridged dinuclear structures for 1a and 2b. Characterization of the compounds by IR, 1H- and 13C NMR spectroscopy confirmed coordination of the ylide to the metal through the carbon atom. In addition, the antibacterial effects of DMSO-solutions of the complexes were investigated by the disc diffusion method against three Gram positive and three negative bacteria. All complexes represent antibacterial activity against these bacteria with high levels of inhibitory potency exhibited against the Gram-positive species.
- Sabounchei, Seyyed Javad,Bagherjeri, Fateme Akhlaghi,Boskovic, Colette,Gable, Robert W.,Karamian, Roya,Asadbegy, Mostafa
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p. 265 - 270
(2013/03/14)
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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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- Studies on Carbonyl Stabilized Sulphonium Ylids : Reaction with α,β-Unsaturated Carbonyl Compounds
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1,2,3-Trisubstituted-cyclopropanes (3a-j) have been prepared by the reaction of the sulphur ylids phenacylidenedimethylsulphurane (1a) and 4-methylphenacylidenedimethylsulphurane (1b) with α,β-unsaturated ketones (2).The carbonyl stabilized ?-sulphuranes (1) have been generated from their corresponding salts.Structural assignments of the products are based on their IR and PMR data.
- Tewari, R. S.,Awasthi, A. K.
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p. 168 - 169
(2007/10/02)
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