- A short and efficient diastereoselective synthesis of 2'-substituted 2- cyclopropylglycines
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Diastereomerically pure-2-cyclopropylglycines 2,2'-substituted with an electron-withdrawing group, were prepared in two steps by Michael addition of the glycine equivalent 2-(diphenylmethylene-amino)acetate 11 to various Michael acceptors of type I with s
- Zindel,De Meijere
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- Isomerisation of Vinyl Sulfones for the Stereoselective Synthesis of Vinyl Azides
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Reported is the construction, and facile base-mediated conversation of ten differently substituted 3-azido E-vinyl sulfones (γ-azido-α,β-unsaturated sulfones) into their isomeric vinyl azide counterparts. The requisite 3-azido E-vinyl sulfones were prepared from 3-bromo E-vinyl sulfones, which in turn were accessed from allyl sulfones via a bromination-elimination sequence. In relation to this a one-pot azidation-isomerisation sequence was developed which enabled the direct formation of the vinyl azides from the corresponding 3-bromo E-vinyl sulfones. Similarly, a convenient one-pot Horner–Wadsworth–Emmons olefination-isomerisation approach was utilised in order to prepare some of the allylic sulfones used in this study. The vinyl azide forming process typically proceeded with high levels of Z-selectivity, although this was dependent on the vinyl sulfone substitution pattern. Thus, with either no substituent or a methyl group in the γ- or β-position, relative to the sulfone, good, to high levels of Z-selectivity (Z/E = 85:15 to ≥ 95:5) were obtained. However, incorporation of an α-sulfonyl methyl substituent led to an E-selective process (Z/E = 20:80). A non-bonding interaction between the azido group and the α-sulfonyl vinylic proton is proposed, which acts as a conformational control mechanism to help guide the stereochemical outcome.
- Collins, Niall,Connon, Robert,Evans, Paul,Sánchez-Sanz, Goar
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supporting information
p. 6228 - 6235
(2020/10/02)
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- A practical synthesis of functionalized isoindolinones via [3?+?3] benzannulation of 1,3-bissulfonylpropenes and 4-arylmethylene-2,3-dioxopyrrolidines
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A straightforward synthesis of isoindolinones has been developed via a [3 + 3] benzannulation of 4-arylmethylene-2,3-dioxopyrrolidines and 1,3-bissulfonylpropenes (or 4-sulfonylcrotonates). A series of functionalized isoindolinones were obtained in excellent yields. The reaction could be carried out under mild conditions without transition metal catalyst. The finding provides a practical approach for the preparation of isoindolinone derivatives with potential biological activities.
- Tang, Xiang-zheng,zhou, Jing-xuan,Liang, Hua-ju,Zhang, Xue-jing,Yan, Ming,Chan, Albert S.C.
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supporting information
p. 147 - 149
(2018/12/11)
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- Discovery of a quinoline-based phenyl sulfone derivative as an antitrypanosomal agent
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A series of natural products-based phenyl sulfone derivative and their property-based analogues were investigated as potential growth inhibitors of Trypanosoma brucei. Trypanosoma brucei is a kinetoplastid protozoan parasite that causes trypanosomiasis. In this work, we found that nopol- and quinoline-based phenyl sulfone derivative were the most active and selective for T. brucei, and they were not reactive towards the active thiol of T. brucei's cysteine protease rhodesain. A thiol reactive variant of the quinoline-based phenyl sulfone was subsequently investigated and found to be a moderate inhibitor of rhodesain. The quinoline-based compound that is not reactive towards rhodesain can serve a template for phenotypic-based lead discovery while its thiol-active congener can serve as template for structure-based investigation of new antitrypanosomal agents.
- Zhang, Huaisheng,Collins, Jasmine,Nyamwihura, Rogers,Ware, Shelbi,Kaiser, Marcel,Ogungbe, Ifedayo Victor
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supporting information
p. 1647 - 1651
(2018/04/20)
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- Facile synthesis of substituted diaryl sulfones: Via a [3 + 3] benzannulation strategy
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A base-mediated [3 + 3] benzannulation strategy for the conversion of 1,3-bis(sulfonyl)propenes and β,γ-unsaturated α-ketoesters to diaryl sulfones has been developed. This method provides facile, metal-free and efficient access to highly substituted diaryl sulfones in good to excellent yields. In addition, the sulfonyl group could be easily removed or converted to other functional groups via an organostannane intermediate.
- Tang, Xiang-Zheng,Tong, Lang,Liang, Hua-Ju,Liang, Jie,Zou, Yong,Zhang, Xue-Jing,Yan, Ming,Chan, Albert S. C.
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supporting information
p. 3560 - 3563
(2018/05/26)
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- Direct N-H/α,α,β,β-C(sp3)-H functionalization of piperidine via an azomethine ylide route: synthesis of spirooxindoles bearing 3-substituted oxindoles
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A protocol for the direct functionalization of N-H/α,α,β,β-C(sp3)-H of piperidine without any metal or external oxidants is reported. This reaction is promoted by 4-(trifluoromethyl)benzoic acid via an azomethine ylide intermediate. This is a simple method for the synthesis of spirooxindoles bearing 3-substituted oxindole moieties.
- Du, Yanlong,Yu, Aimin,Jia, Jiru,Zhang, Youquan,Meng, Xiangtai
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supporting information
p. 1684 - 1687
(2017/02/10)
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- Asymmetric organocatalytic 1,6-conjugate addition of aldehydes to dienic sulfones
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An unprecedented 1,6-enamine conjugate addition exploiting the charge delocalization in 1,3-bis(sulfonyl) butadienes has been developed. By appropriately designing a Michael acceptor, unique reactivities were obtained for the formation of highly valuable
- Murphy, John J.,Quintard, Adrien,McArdle, Patrick,Alexakis, Alexandre,Stephens, John C.
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supporting information; scheme or table
p. 5095 - 5098
(2011/06/26)
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