- Aryltrifluoromethylative cyclization of unactivated alkenes by the use of PhICF3Cl under catalyst-free conditions
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A concise and catalyst-free aryltrifluoromethylative cyclization of unactivated alkenes has been developed herein. The use of PhICF3Cl as a powerful trifluoromethylating agent allows easy transformations. A set of trifluoroethylated carbocycles and aza-hereocycles were efficiently synthesized in good yield and selectivity. A broad substrate scope, mild reaction conditions, and easy operation would make this method well-suited for applications.
- Guo, Jia,Xu, Cong,Liu, Xiaowei,Wang, Mang
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supporting information
p. 2162 - 2168
(2019/02/27)
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- Unnatural α-amino ethyl esters from diethyl malonate or ethyl β-bromo-α-hydroxyiminocarboxylate
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We have explored here the scope of the age-old diethyl malonate-based accesses to α-amino esters involving Knoevenagel condensations of diethyl malonate on aldehydes, reductions of the resulting alkylidenemalonates, the preparation of the corresponding α-hydroxyimino esters and their final reduction. This synthetic pathway turned out to be general although some unexpected limitations were encountered. The synthetic modifications of some of the intermediates - using Suzuki-Miyaura coupling or cycloadditions - before undertaking the oximation step - provided accesses to further α-amino esters. Moreover, other pathways to α-hydroxyimino esters were explored including an attempt to improve the cycloadditions between ethyl β-bromo-α-hydroxyiminocarboxylate and various alkylfuranes.
- Coutant, Eloi P.,Hervin, Vincent,Gagnot, Glwadys,Ford, Candice,Baatallah, Racha,Janin, Yves L.
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p. 2853 - 2860
(2018/11/26)
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- Synthesis and insecticidal activity of mesoionic pyrido[1,2-α]pyrimidinone derivatives containing a neonicotinoid moiety
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Mesoionic pyrido[1,2-α]pyrimidinone derivatives containing a neonicotinoid moiety were designed, synthesized, and evaluated for their insecticidal activity. Some of the title compounds showed remarkable insecticidal properties against Aphis craccivora. Compound I13 exhibited satisfactory insecticidal activity against A. craccivora. Meanwhile, label-free proteomics analysis of compound I13 treatment identified a total of 821 proteins. Of these, 35 proteins were up-regulated, whereas 108 proteins were down-regulated. Differential expressions of these proteins reflected a change in cellular structure and metabolism.
- Pan, Jianke,Yu, Lu,Liu, Dengyue,Hu, Deyu
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- Intermolecular Photocatalytic C-H Functionalization of Electron-Rich Heterocycles with Tertiary Alkyl Halides
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The coupling of tertiary alkyl halides with electron-rich arenes is promoted by visible-light photoredox catalysis. Tris[2-phenylpyridinato-C2,N]iridium(III) [Ir(ppy)3] was the optimal catalyst, enabling direct reduction of the halide from the excited state, and thereby eliminating the requirement for a stoichiometric electron donor. High yields were obtained when the aromatic component was used in excess, although equimolar amounts afforded only slightly diminished yields. The reaction tolerates a number of functional groups, including allyl, ester, amide, or carbamate. The efficiency of this reaction has been improved through demonstration of scale-up in flow, and a new substituted Ir(ppy)3 derivative was isolated and characterized.
- Swift, Elizabeth C.,Williams, Theresa M.,Stephenson, Corey R. J.
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supporting information
p. 754 - 758
(2016/03/09)
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- Catalytic direct arylation with aryl chlorides, bromides, and iodides: Intramolecular studies leading to new intermolecular reactions
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A catalyst for the intramolecular direct arylation of a broad range of simple and heterocyclic arenes with aryl iodides, bromides, and chlorides has been developed. These reactions occur in excellent yield and are highly selective. Studies with aryl iodides substrates revealed that catalyst poisoning occurs due to the accumulation of iodide in the reaction media. This can be overcome by the addition of silver salts which also permits these reactions to occur at lower temperature. The utility of the methodology is illustrated by a rapid synthesis of a carbazole natural product and by the synthesis of sterically encumbered tetra-ortho-substituted biaryls via ring-opening reactions of the direct arylation products. Mechanistic investigations have provided insight into the catalyst's mode of action and show the presence of a kinetically significant C-H bond cleavage in palladium-catalyzed direct arylation of simple arenes. Knowledge garnered from these studies has led to the development of new intermolecular arylation reactions with previously inaccessible arenes, opening the door for the development of other new direct arylation processes.
- Campeau, Louis-Charles,Parisien, Mathieu,Jean, Annie,Fagnou, Keith
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p. 581 - 590
(2007/10/03)
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- Amine preparation
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A method of making (R)-N- 1-(3-methoxyphenyl)ethyl!-3-(2-chlorobenzene)propanamine which involves reducing the appropriate amidyl or iminyl precursor with an appropriate reducing agent. The appropriate amidyl or iminyl precursor is made from a synthesis involving the use of (R)-3-methoxy-α-methylbenzylamine. A method of condensing a nitrile with a primary or secondary amine to form an imine involves the reaction of a nitrile with diisobutylaluminum hydride; and then reacting the resultant compound with a primary or secondary amine to form the imine. The process is especially useful for producing enantiomerically pure chiral imines, and, ultimately, amines. Typical such imines have the formula: STR1 wherein R, R1, R2 and R3 are independently selected from the group consisting of hydrogen, substituted or unsubstituted alkyl, aryl and aralkyl.
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- Reactions of N-Substituted Pyridinium Cations with Carbanions: 5,6,8,9-Tetrahydro-7-phenylbisbenzoacridine, a Superior Leaving Group
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N-Substituents are transferred from pyridinium cations to malonate, cyanoacetate , and acetoacetate carbanions: for alkyl substituents the pentacyclic derivatives (4) attain the required activity.
- Katritzky, Alan R.,Thind, Sukhpal S.
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p. 661 - 663
(2007/10/02)
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