- Site-Selective Ruthenium-Catalyzed C-H Bond Arylations with Boronic Acids: Exploiting Isoindolinones as a Weak Directing Group
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Biologically relevant N-arylisoindolinones efficiently underwent arylation reactions under ruthenium catalysis via C-H bond functionalization. The reactions exclusively led to monoarylated products, and only ortho selectivity was observed in the aromatic ring connected to the nitrogen atom. Interestingly, no C-H bond functionalization was observed in the other benzene ring in the ortho position with respect to the carbonyl group. This ruthenium-catalyzed reaction displayed a high functional group tolerance, and it employed readily available and benchmark stable boronic acid and potassium aryltrifluoroborate derivatives as coupling partners. An appealing late-stage functionalization of indoprofen applying this methodology is showcased.
- Yuan, Yu-Chao,Bruneau, Christian,Roisnel, Thierry,Gramage-Doria, Rafael
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p. 12893 - 12903
(2019/09/13)
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- Ru-Catalyzed Selective C-H Bond Hydroxylation of Cyclic Imides
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We report on cyclic imides as weak directing groups for selective monohydroxylation reactions using ruthenium catalysis. Whereas acyclic amides are known to promote the hydroxylation of the C(sp2)-H bond enabling five-membered ring ruthenacycle intermediates, the cyclic imides studied herein enabled the hydroxylation of the C(sp2)-H bond via larger six-membered ruthenacycle intermediates. Furthermore, monohydroxylated products were exclusively obtained (even in the presence of overstoichiometric amounts of reagents), which was rationalized by the difficulty to accommodate coplanar intermediates once the first hydroxyl group was introduced into the substrate. The same reactivity was observed in the presence of palladium catalysts.
- Yuan, Yu-Chao,Bruneau, Christian,Dorcet, Vincent,Roisnel, Thierry,Gramage-Doria, Rafael
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p. 1898 - 1907
(2019/02/05)
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- Ruthenium(ii)-catalysed selective C(sp2)-H bond benzoxylation of biologically appealing: N -arylisoindolinones
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Site- and regio-selective aromatic C-H bond benzoxylations were found to take place using biologically appealing N-arylisoindolinones under ruthenium(ii) catalysis in the presence of (hetero)aromatic carboxylic acid derivatives as coupling partners. Besides the presence of two potential C(sp2)-H sites available for functionalization in the substrates, exclusive ortho selectivity was achieved in the phenyl ring attached to the nitrogen atom. Notably, the reactions occurred in a selective manner as only mono-functionalized products were formed and they tolerated a large number of functional chemical groups. The ability of the cyclic tertiary amide within the isoindolinone skeleton to act as a weak directing group in order to accommodate six-membered ring ruthenacycle intermediates appears to be the key to reach such high levels of selectivity. In contrast, the more sterically demanding cyclic imides were unreactive under identical reaction conditions.
- Yuan, Yu-Chao,Bruneau, Christian,Roisnel, Thierry,Gramage-Doria, Rafael
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p. 7517 - 7525
(2019/08/20)
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- Facile syntheses and characterization of hyperbranched poly(ester-amide)s from commercially available aliphatic carboxylic anhydride and multihydroxyl primary amine
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A new method for synthesis of novel hyperbranched poly(ester-amide)s from commercially available AA′ and CBx type monomers has been developed on the basis of a series of model reactions. The hyperbranched poly(ester-amide)s with multihydroxyl end groups are prepared by thermal polycondensation of carboxyl anhydrides (AA′) and multihydroxyl primary amine (CBx) without any catalyst and solvent. The reaction mechanism in the initial stage of polymerization was investigated with in situ 1H NMR. In the initial stage of the reaction, primary amino groups of 2-amino-2-ethyl-1,3-propanediol (AEPO) or tris(hydroxymethyl)aminomethane (THAM) react rapidly with anhydride, forming an intermediate which can be considered as a new ABx type monomer. Further self-polycondensation reactions of the ABx molecules produce hyperbranched polymers. Analysis using 1H and 13C NMR spectroscopy revealed the degree of branching of the resulting polymers ranging from 0.36 to 0.55. These hyperbranched poly(ester-amide)s contain configurational isomers observed by 13C and DEPT 13C NMR spectroscopy, possess high molecular weights with broad distributions and display glass-transition temperatures (Tgs) between 7 and 96°C. The thermogravimetric analytic measurements revealed the decomposition temperature at 10% weight-loss temperatures (Td10%) ranging from 212 to 325°C. Among the hyperbranched poly(ester-amide)s obtained, the polymers with cyclohexyl molecular skeleton structure exhibit the lowest branching degree, the highest glass-transition temperatures, and the best thermal stability.
- Li, Xiuru,Zhan, Jie,Li, Yuesheng
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p. 7584 - 7594
(2007/10/03)
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- Comparative Study of the Reactions of Dilithiated Vicinal Diesters and Dilithiated 1,2-Dicarboximides with Methyl Iodide, α,ω-Dihalides, α,ω-Ditosylates, and ω-Bromo Esters
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The reactions od dilithiated dimethyl cyclohexane-1,2-dicarboxylate (1), dimethyl 4-cyclohexene-1,2-dicarboxylate (2), N-substituted cyclohexane-1,2-dicarboximides 11a-c, and N-phenyl-4-cyclohexene-1,2-dicarboximides 18 with a variety of substrates have b
- Bilyard, Kevin G.,Garratt, Peter J.,Hunter, Roger,Lete, Ester
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p. 4731 - 4736
(2007/10/02)
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