- Catalytic asymmetric [3+2] cycloaddition of isomünchnones with methyleneindolinones
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An efficient enantioselective [3+2] cycloaddition of isomünchnones with methyleneindolinones that are generated by anin situintramolecular addition of the carbonyl group to rhodium carbenes is realized with a chiralN,N′-dioxide/Zn(ii) complex as a Lewis acid. A series of chiral oxa-bridged 3-spiropiperidines are obtained in high yields with excellent dr and excellent ee values.
- Feng, Xiaoming,Hu, Xinyue,Lin, Lili,Wang, Kaixuan,Xu, Chaoran,Zhou, Yuqiao
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p. 8917 - 8920
(2021/09/10)
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- NHC-Catalyzed Aldol-Like Reactions of Allenoates with Isatins: Regiospecific Syntheses of γ-Functionalized Allenoates
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An N-heterocyclic carbene (NHC) catalyzed γ-specific aldol-like reaction between allenoates and isatins has been achieved under mild conditions, giving trisubstituted allene derivatives bearing isatin moiety in moderate to good yields with high diastereoselectivity and excellent atom efficiency. The DFT computations indicated that the formation of the γ-adduct was more energetically favorable than that of the α-adduct. The result reported herein opens a new route for NHC-promoted allenoate-involved reaction.
- Li, Sha,Tang, Ziwei,Wang, Yang,Wang, Dan,Wang, Zhanlin,Yu, Chenxia,Li, Tuanjie,Wei, Donghui,Yao, Changsheng
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p. 1306 - 1310
(2019/02/26)
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- Heavier Carbonyl Olefination: The Sila-Wittig Reaction
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The Wittig reaction is one of the most versatile tools in the repertoire of organic chemists. Thus, a broad variety of carbonyl compounds can be converted to tailor-made alkenes with phosphorus ylides under mild conditions. However, no comparable reaction has been reported for silanones, the silicon congeners of ketones. Here, we demonstrate for the first time the successful application of the Wittig olefination to iminosilylsilanone 1. The selective formation of a series of silenes (R2Sia? CR2) via the sila-Wittig reaction revealed an unprecedented approach to otherwise elusive compounds. In addition, the highly reactive and zwitterionic nature of 1 was also susceptible to nucleophilic attacks and cycloaddition reactions by and with the phosphorus ylides. Our results therefore make another important contribution to discovering the differences and similarities between carbon and silicon.
- Reiter, Dominik,Frisch, Philipp,Szilvási, Tibor,Inoue, Shigeyoshi
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supporting information
p. 16991 - 16996
(2019/10/16)
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- Nickel-catalyzed, ligand-free, diastereoselective synthesis of 3-methyleneindan-1-ols
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Nickel-catalyzed, highly diastereoselective annulations between activated allenes and 2-acetylarylboronic acid or 2-formylarylboronic acids are reported. No ligand for nickel is required, and the reactions proceed efficiently at room temperature to give a broad range of substituted 3-methyleneindan-1-ols. Preliminary results of an enantioselective variant are also described.
- Panchal, Heena,Clarke, Christopher,Bell, Charles,Karad, Somnath Narayan,Lewis, William,Lam, Hon Wai
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supporting information
p. 12389 - 12392
(2018/11/20)
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- Photoinduced Intermolecular [4+2] Cycloaddition Reaction for Construction of Benzobicyclo[2.2.2]octane Skeletons
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A novel and efficient method for the synthesis of highly substituted benzobicyclo[2.2.2]octane skeletons has been explored. Under UV-light irradiation, o-divinylbenzenes underwent a pericyclic reaction to form the cyclic o-quinodimethane intermediates which were subsequently reacted with olefins through [4+2] addition to construct the benzobicyclo[2.2.2]octane skeletons in mild conditions. Gram scale reactions demonstrated the synthetic potential application of this protocol.
- Liu, Qiang,Wang, Junlei,Li, Dazhi,Yang, Chao,Xia, Wujiong
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p. 1389 - 1402
(2017/02/10)
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- Synthesis and antimicrobial activity of N-aryl-4-(cyano/alkoxycarbonyl)-5-(pyridin-3-yl)-1H/3H-1,2,3-triazole derivatives
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A convenient synthesis of a new series of N-aryl-5-(pyridin-3-yl)-1H/3H-1,2,3-triazole-4-carbonitriles and alkyl N-aryl-5-(pyridin-3-yl)-1H/3H-1,2,3-triazole-4-carboxylic acid esters is reported. The newly synthesized 5-(pyridin-3-yl)-1,2,3-triazole derivatives are evaluated for their antibacterial and antifungal activity. Some of these triazole derivatives have exhibited moderate antimicrobial activity.
- Komsani, Jayaram Reddy,Avula, Sreenivas,Koppireddi, Satish,Koochana, Pranay Kumar,Usn, Murty,Yadla, Rambabu
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p. 764 - 772
(2015/05/13)
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- Copper-catalyzed asymmetric synthesis and comparative aldose reductase inhibition activity of (+)/(-)-1,2-benzothiazine-1,1-dioxide acetic acid derivatives
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A copper catalyst system for the asymmetric 1,4-hydrosilylation of the α,β-unsaturated carboxylate class was developed by which synthesis of (+)- and (-)-enantiomers of 1,2-benzothiazine-1,1-dioxide acetates has been achieved with a good yield and an excellent level of enantioselectivity. A comparative structure-activity relationship study yielded the following order of aldose reductase inhibition activity: (-)-enantiomers > racemic > (+)-enantiomers. Further, a molecular docking study suggested that the (-)-enantiomer had significant binding affinity and thus increased inhibition activity.
- Parveen, Shagufta,Hussain, Saghir,Qin, Xiangyu,Hao, Xin,Zhu, Shaojuan,Rui, Miao,Zhang, Shuzhen,Fu, Fengyan,Ma, Bing,Yu, Qun,Zhu, Changjin
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p. 4963 - 4972
(2014/06/23)
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- Kinetic and mechanistic study on the thermal reactivity of stabilized phosphorus ylides, part 3: [(Acetyl) (arylcarbamoyl)-methylene] triphenylphosphoranes and [(alkoxy-carbonyl) (arylcarbamoyl)-methylene] triphenylphosphoranes and their thiocarbamoyl analogues
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A series of five [(acety])(arylcarbabmoyl)methylene]triphenyl-phosphoranes 1a-e and their thiocarbamoyl analogues 2a-e, |(alkoxycarbonyl)(arylcarbamoyl) methylene]triphenylphosphoranes 3a-e and thiocarbamoyl analogues 4a-e were prepared and fully characterized. All ylides are found under conditions of flash vacuum pyrolysis to fragment giving arylisocyanate or isothiocyanate and acetyl ylides or alkoxy ylides which undergo thermal extrusion of Ph3PO. A kinetic study shows that these reactions are unimolecular and are of first-order nature with no significant substituent effect. The thiocarbamoyl ylides 2 react from 4.6 to 42 times faster than their carbamoyl ylides 1, while the thiocarbamoyl ylides 4 react from 6.6 to 20.9 times faster than their carbamoyl ylides 3.
- Aitken, R. Alan,Al-Awadi, Nouria A.,Dawson, Graham,El-Dusouqui, Osman,Kaul, Kamini,Kumar, Ajith
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- Phosphine-catalyzed synthesis of 1,3-dioxan-4-ylidenes
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(Chemical Equation Presented) A phosphine-catalyzed reaction of an allenoate with aldehydes furnished (2,6-diaryl-[1,3]dioxan-4-ylidene)-acetates 4 in excellent to moderate yields with complete diastereoselectivity and high E/Z-selectivities. Upon removal of the acetal functionality in this domino reaction product 4, δ-hydroxy-β-ketoester 11 was obtained. The reported vinylphosphonium-based approach provides a new way to achieve a synthesis of δ-hydroxy-β-ketoesters that differs from the classical dianion-based approach.
- Zhu, Xue-Feng,Henry, Christopher E.,Wang, Jay,Dudding, Travis,Kwon, Ohyun
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p. 1387 - 1390
(2007/10/03)
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