- Catalytic atroposelective dynamic kinetic resolutions and kinetic resolutions towards 3-arylquinolinesviaSNAr
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Herein we report the catalytic atroposelective syntheses of pharmaceutically relevant 3-arylquinolinesviathe nucleophilic aromatic substitution (SNAr) of thiophenols into 3-aryl-2-fluoroquinolines mediated by catalytic amounts of Cinchona alkaloid-derived ureas. These reactions displayed a spectrum of dynamic kinetic resolution (DKR) and kinetic resolution (KR) characters depending upon the stereochemical stability of the starting material. Low barrier substrates proceededviaDKR while higher barrier substrates proceededviaKR. On the other hand, substrates with intermediate stabilities displayed hallmarks of both DKR and KR. Finally, we also show that we can functionalize the atropisomerically enriched quinolines into pharmaceutically privileged scaffolds with minimal observed racemization.
- Cardenas, Mariel M.,Saputra, Mirza A.,Gordon, Deane A.,Sanchez, Andrea N.,Yamamoto, Nobuyuki,Gustafson, Jeffrey L.
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supporting information
p. 10087 - 10090
(2021/10/06)
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- Intramolecular palladium-catalyzed alkane C-H arylation from aryl chlorides
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The first examples of efficient and general palladium-catalyzed intramolecular C(sp3)-H arylation of (hetero)aryl chlorides, giving rise to a variety of valuable cyclobutarenes, indanes, indolines, dihydrobenzofurans, and indanones, are described. The use of aryl and heteroaryl chlorides significantly improves the scope of C(sp3)-H arylation by facilitating the preparation of reaction substrates. Careful optimization studies have shown that the palladium ligand and the base/solvent combination are crucial to obtaining the desired class of product in high yields. Overall, three sets of reaction conditions employing PtBu3, PCyp3, or PCy3 as the palladium ligand and K 2CO3/DMF or Cs2CO3/pivalic acid/mesitylene as the base/solvent combination allowed five different classes of products to be accessed using this methodology. In total, more than 40 examples of C-H arylation have been performed successfully. When several types of C(sp3)-H bond were present in the substrate, the arylation was found to occur regioselectively at primary C-H bonds vs secondary or tertiary positions. In addition, in the presence of several primary C-H bonds, selectivity trends correlate with the size of the palladacyclic intermediate, with five-membered rings being favored over six- and seven-membered rings. Regio- and diastereoselectivity issues were studied computationally in the prototypal case of indane formation. DFT(B3PW91) calculations demonstrated that C-H activation is the rate-determining step and that the creation of a C-H agostic interaction, increasing the acidity of a geminal C-H bond, is a critical factor for the regiochemistry control.
- Rousseaux, Sophie,Davi, Michael,Sofack-Kreutzer, Julien,Pierre, Cathleen,Kefalidis, Christos E.,Clot, Eric,Fagnou, Keith,Baudoin, Olivier
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supporting information; experimental part
p. 10706 - 10716
(2010/09/17)
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- Method for optical measurement of multi-stranded nucleic acid using cyanine dyes
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A method for optical measurement of a multi-stranded nucleic acid which comprises the step of bringing a compound into contact with a multi-stranded nucleic acid wherein said compound is capable of interacting with the multi-stranded nucleic acid, wherein the compound has the following properties:(a) the compound can exist in a substantially colorless and non-fluorescent state under at least one condition in an aqueous solution in the absence of the multi-stranded nucleic acid, and(b) when the multi-stranded nucleic acid is allowed to exist in the condition defined in the above (a), the compound changes to a substantially colored state based on an interaction with the multi-stranded nucleic acid and substantially expresses fluorescent property based on said interaction.
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