- Silylium-Ion-Promoted (5+1) Cycloaddition of Aryl-Substituted Vinylcyclopropanes and Hydrosilanes Involving Aryl Migration
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A transition-metal-free (5+1) cycloaddition of aryl-substituted vinylcyclopropanes (VCPs) and hydrosilanes to afford silacyclohexanes is reported. Catalytic amounts of the trityl cation initiate the reaction by hydride abstraction from the hydrosilane, and further progress of the reaction is maintained by self-regeneration of the silylium ions. The new reaction involves a [1,2] migration of an aryl group, eventually furnishing 4- rather than 3-aryl-substituted silacyclohexane derivatives as major products. Various control experiments and quantum-chemical calculations support a mechanistic picture where a silylium ion intramolecularly stabilized by a cyclopropane ring can either undergo a kinetically favored concerted [1,2] aryl migration/ring expansion or engage in a cyclopropane-to-cyclopropane rearrangement.
- Bonetti, Vittorio,He, Tao,Klare, Hendrik F. T.,Oestreich, Martin,Wang, Guoqiang
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supporting information
p. 12186 - 12191
(2020/05/22)
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- B(C6F5)3-Catalyzed Hydrosilylation of Vinylcyclopropanes
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A hydrosilylation of vinylcyclopropanes (VCPs) catalyzed by the strong boron Lewis acid B(C6F5)3 is reported. For the majority of VCPs, little or no ring opening of the cyclopropyl unit is observed. Conversely, for VCPs with bulky R groups, such as ortho-substituted aryl rings or branched alkyl residues, ring opening is the exclusive reaction pathway. This finding is explained by the thwarted hydride delivery to a sterically shielded, β-silicon-stabilized cyclopropylcarbinyl cation intermediate.
- He, Tao,Long, Peng-Wei,Oestreich, Martin
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supporting information
p. 7383 - 7386
(2020/10/12)
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- Br?nsted acid mediated intramolecular cyclopropane ring expansion/[4 + 2]-cycloaddition
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A cascade reaction of 3-hydroxy-2-phenylisoindolin-1-one and cyclopropyl ketone has been developed via a Br?nsted acid-promoted ring-opening/intramolecular cross-cycloaddition/[4 + 2]-cycloaddition process. The developed methodology provides straightforward access to pentacyclic isoindolin-1-one derivatives under simple reaction conditions.
- Li, Jian,Zhu, Shangrong,Xu, Qiuneng,Liu, Li,Yan, Shenghu
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p. 10004 - 10008
(2019/12/23)
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- Structure-Kinetic Profiling of Haloperidol Analogues at the Human Dopamine D2 Receptor
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Haloperidol is a typical antipsychotic drug (APD) associated with an increased risk of extrapyramidal side effects (EPSs) and hyperprolactinemia relative to atypical APDs such as clozapine. Both drugs are dopamine D2 receptor (D2R) antagonists, with contrasting kinetic profiles. Haloperidol displays fast association/slow dissociation at the D2R, whereas clozapine exhibits relatively slow association/fast dissociation. Recently, we have provided evidence that slow dissociation from the D2R predicts hyperprolactinemia, whereas fast association predicts EPS. Unfortunately, clozapine can cause severe side effects independent of its D2R action. Our results suggest an optimal kinetic profile for D2R antagonist APDs that avoids EPS. To begin exploring this hypothesis, we conducted a structure-kinetic relationship study of haloperidol and revealed that subtle structural modifications dramatically change binding kinetic rate constants, affording compounds with a clozapine-like kinetic profile. Thus, optimization of these kinetic parameters may allow development of novel APDs based on the haloperidol scaffold with improved side-effect profiles.
- Fyfe, Tim J.,Kellam, Barrie,Sykes, David A.,Capuano, Ben,Scammells, Peter J.,Lane, J. Robert,Charlton, Steven J.,Mistry, Shailesh N.
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p. 9488 - 9520
(2019/11/11)
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- Mild Ring Contractions of Cyclobutanols to Cyclopropyl Ketones via Hypervalent Iodine Oxidation
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An iodine-mediated oxidative ring contraction of cyclobutanols has been developed. The reaction allows the synthesis of a wide range of aryl cyclopropyl ketones under mild and eco-friendly conditions. A variety of functional groups including aromatic or alkyl halides, ethers, esters, ketones, alkenes, and even aldehydes are nicely tolerated in the reaction. This is in contrast with traditional synthetic approaches for which poor functional group tolerance is often a problem. The practicality of the method is also highlighted by the tunability of iodine oxidation system. Specifically, combining the iodine(III) reagent with an appropriate base allows the reaction to accommodate a range of challenging electron-rich arene substrates. The facile scalability of this reaction is also exhibited herein. (Figure presented.).
- Sun, Yan,Huang, Xin,Li, Xiaojin,Luo, Fan,Zhang, Lei,Chen, Mengyuan,Zheng, Shiya,Peng, Bo
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supporting information
p. 1082 - 1087
(2018/01/27)
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- A cascade approach to fused indolizinones through Lewis acid-copper(i) relay catalysis
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A relay catalytic cascade process involving Lewis acid triggered ring-opening of cyclopropyl ketones with nitriles, the copper(i)-catalyzed Ritter process, and acid-promoted N-acyliminium ion cyclization is described, which efficiently provides thieno-, furano-, and benzo-indolizinones in moderate to good yields. The Royal Society of Chemistry 2013.
- Huang, Huawen,Ji, Xiaochen,Wu, Wanqing,Jiang, Huanfeng
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supporting information
p. 3351 - 3353
(2013/06/04)
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- Lithium sulfur battery
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A lithium sulfur battery comprising an electrolyte solvent which comprises at least one fluorosubstituted compound is described. Preferred fluorosubstituted compounds which are predominantly solvents are notably selected from the group consisting of fluorosubstituted carboxylic acid esters, fluorosubstituted carboxylic acid amides, fluorosubstituted fluorinated ethers, fluorosubstituted carbamates, fluorosubstituted cyclic carbonates, fluorosubstituted acyclic carbonates, fluorosubstituted ethers, perfluoroalkyl phosphoranes, fluorosubstituted phosphites, fluorosubstituted phosphates, fluorosubstituted phosphonates, and fluorosubstituted heterocycles. Monofluoroethylene carbonate, cis-difluoroethylene carbonate, trans-difluoroethylene carbonate, 4,4-difluoroethylene carbonate, trifluoroethylene carbonate, tetrafluoroethylene carbonate, 4-fluoro-4-methyl-1,3-dioxolane-2-one, 4-fluoro-4-ethyl-1,3-dioxolane-2-one, 2,2,2-trifluoroethyl-methyl carbonate, 2,2,2-trifluoroethyl-fluoromethyl carbonate are preferred. The solvent may further comprise a non-fluorinated solvent, e.g., ethylene carbonate, a dialkyl carbonate, or propylene carbonate. Use of such fluorinated compound as additive for such batteries and specific electrolyte solutions.
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