- Organocatalytic Enantioselective Selenosulfonylation of a C-C Double Bond to Form Two Stereogenic Centers in an Aqueous Medium
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Organocatalytic selenosulfonylation of the C-C double bond of α,β-unsaturated ketones to construct two contiguous stereogenic centers in an aqueous medium was described. A series of α-selenyl and β-sulfonyl ketones with various functional groups were synthesized in good yields and enantioselectivities with saturated NaCl solution as the solvent. In addition, this protocol had been successfully scaled up to a decagram scale via a simple workup procedure.
- Chen, Zhili,Hu, Fangli,Huang, Shengli,Zhao, Zhengxing,Mao, Hui,Qin, Wenling
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p. 8100 - 8111
(2019/06/17)
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- Nonenzymatic Dynamic Kinetic Resolution of in situ Generated Hemithioacetals: Access to 1,3-Disubstituted Phthalans
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The first nonenzymatic DKR reaction of hemithioacetals is developed. Hemithioacetals were formed in situ via thiol addition and subsequently underwent an intramolecular oxa-Michael reaction. The scope of the reaction was quite broad ranging from aliphatic to aromatic substituents and 1,3-disubstituted-1,3-dihyroisobenzofuran products were obtained in good yields with moderate diastereoselectivities and high enantioselectivities. (Figure presented.).
- Nath, Utpal,Chowdhury, Deepan,Pan, Subhas Chandra
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p. 1628 - 1633
(2018/03/21)
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- Iodine-mediated intramolecular amination of ketones: The synthesis of 2-acylindoles and 2-acylindolines by tuning N-protecting groups
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A general method for constructing both 2-acylindoles and 2-acylindolines via I2-mediated intramolecular C-N bond formation is presented, and the selective formation of either 2-acylindoles or 2-acylindolines just depends on the nitrogen protecting groups used in the same substrate skeletons. The Royal Society of Chemistry.
- Gao, Wen-Chao,Jiang, Shan,Wang, Ruo-Lin,Zhang, Chi
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supporting information
p. 4890 - 4892
(2013/07/05)
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- Synthesis and biological activity of alkylidene-substituted cephems and penams
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The condensation of tert-butyl esters of 3-methyl-7-oxoceph-3-em-4- carboxylic and 6-oxopenicillanic acids with a series of 2- oxoalkylidene(triphenyl)phosphoranes gave tert-butyl esters of new cephalosporin and penicillin analogs with an alkylidene substituent in the β-lactam ring. Most of these products were oxidized by meta-chloroperbenzoic acid to the corresponding sulfones. The cephemes and penams synthesized including the oxidized products displayed high cytotoxicity relative to cancer cells in vitro. Some of the alkylidene-substituted cephems as the free acids, similar to Tazobactam, inhibit the catalytic activity of Enterobacter cloacae penicillinase.
- Potorocina,Vorona,Shestakova,Domracheva,Liepinsh,Veinberg
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experimental part
p. 767 - 775
(2012/02/01)
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- Highly efficient route to functionalized tetrahydrocarbazoles using a tandem cross-metathesis/intramolecular-hydroarylation sequence
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The scope of the novel ruthenium-catalyzed tandem cross-metathesis/ intramolecular-hydroarylation sequence is described. This methodology offers a practical and efficient synthesis of structurally diverse and complex tetrahydrocarbazoles in good to excellent yields (up to 98%). Moreover, preliminary efforts towards the development of an enantioselective version of the current process by sequential catalysis with ruthenium complex and chiral amine are presented, with high yields and enantioselectivities (up to 88% yield and 91% ee).
- An, Xiao-Lei,Chen, Jia-Rong,Li, Chang-Feng,Zhang, Fu-Gen,Zou, You-Quan,Guo, Ying-Cen,Xiao, Wen-Jing
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supporting information; experimental part
p. 2258 - 2265
(2011/06/11)
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- Synthesis of new phosphonium ylides containing thiophene and furan rings and study of their reaction with mercury(II) halides: Spectral and structural characterization
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Reactions of phosphonium ylides (4-MeC6H4) 3PCHC(=O)(2-C4H3S) (tptpy), Ph 3PCHC(=O)(2-C4H3O) (fppy), and (4-MeC 6H4)3PCHC(=O)(4-BrC6H4) (bbtppy) with HgX2 (X=Cl, Br, and I) in equimolar ratios in MeOH as solvent leads to the binuclear products 1-3 (Scheme 1). The bridgesplitting reaction of the binuclear complex [{HgI2(bbtppy)}2] (3c) by DMSO yields the mononuclear complex [HgI2 · (bbtppy) (DMSO)] (3d) (Scheme 2). This bridge-splitting reaction can also be a method for the synthesis of mononuclear products. C-Coordination of the ylide and O-coordination of DMSO are demonstrated by a single-crystal X-ray-analysis of the mononuclear complex 3d. Characterization of the obtained compounds was also performed by means of elemental analysis and IR and 1H-, 31P-, and 13C-NMR spectroscopy. A theoretical study of some HgII complexes with phosphonium ylides is also reported.
- Sabounchei, Seyyed Javad,Jodaian, Vida,Salehzadeh, Sadegh,Samiee, Sepideh,Dadrass, Alireza,Bayat, Mehdi,Khavasi, Hamid Reza
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experimental part
p. 1105 - 1119
(2010/08/21)
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