- Fluorene-Based Multicomponent Reactions
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Fluorene and fluorenone are privileged structures with extensive utility in both materials science and drug discovery. Here, we describe syntheses of those moieties through isocyanide-based multicomponent reactions (IMCRs) and the incorporation of the products in diverse and complex derivatives that can be further utilized. We performed six different IMCRs, based on the dual functionality of 9-isocyano-9H-fluorene, and we describe 23 unprecedented adducts.
- Lei, Xiaofang,Thomaidi, Maria,Angeli, Giasemi K.,D?mling, Alexander,Neochoritis, Constantinos G.
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- The impact of cation structure upon the acidity of triazolium salts in dimethyl sulfoxide
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A series of triazolium salts, selected for their varying electronic and steric properties, were prepared and their pKa values were determined in DMSO at 25 °C using the bracketing indicator method. The effect of each systematic structural variation upon the acidity of the triazolium cation has been considered, in particular examining the effects of systematically altering electronic properties, quantified through the use of Hammett σ parameters. The first pKa value for an azolium salt that generates a mesionic carbene is also reported. These new data allow for the selection of appropriate bases for the deprotonation of such triazolium salts and the potential to correlate the pKa values determined herein with the nucleophilicity of the corresponding carbenes.
- Konstandaras, Nicholas,Dunn, Michelle H.,Guerry, Max S.,Barnett, Christopher D.,Cole, Marcus L.,Harper, Jason B.
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supporting information
p. 66 - 75
(2019/12/26)
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- Leuckart-Wallach Route Toward Isocyanides and Some Applications
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Isocyanide-based multicomponent reactions (IMCR) are among the most important chemical reactions to efficiently generate molecular diversity and have found widespread use in industry and academia. Generally, isocyanides are synthesized in 1-2 steps starting from primary amines. Here, we provide experimental detail on an alternative approach toward formamides and, thus, isocyanides via the Leuckart-Wallach reaction in an improved variation. The resulting >50 synthesized and characterized formamides are useful starting materials for IMCR, as well as other chemistries. The advantage of using the Leuckart-Wallach pathway to formamides and isocyanides is the lower price, on average, of the starting materials, as well as their differential and complementary structural diversity, as compared to the primary amine pathway.
- Neochoritis, Constantinos G.,Zarganes-Tzitzikas, Tryfon,Stotani, Silvia,D?mling, Adrian,Herdtweck, Eberhardt,Khoury, Kareem,D?mling, Alexander
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supporting information
p. 493 - 499
(2015/09/22)
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- A cation-directed two-component cascade approach to enantioenriched pyrroloindolines
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A cascade approach to complex pyrroloindolines bearing all-carbon quaternary stereocentres has been developed. This two-component process uses a chiral ammonium salt to control diastereo- and enantioselectivity in the addition of isocyanides to functionalized alkenes to afford pyrroloindolines with up to three stereocentres. A mechanistic proposal involving intramolecular hydrogen bond activation of the isocyanide is described.
- Wolstenhulme, Jamie R.,Cavell, Alex,Grediak, Matija,Driver, Russell W.,Smith, Martin D.
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supporting information
p. 13585 - 13588
(2015/02/19)
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- Novel multicomponent reaction for the combinatorial synthesis of 2-imidazolines
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(Matrix presented) The three-component condensation between an amine, an aldehyde, and an α-acidic isocyanide efficiently provides substituted 2-imidazolines in a one-pot reaction under mild conditions.
- Bon, Robin S.,Hong, Chongen,Bouma, Marinus J.,Schmitz, Rob F.,De Kanter, Frans J. J.,Lutz, Martin,Spek, Anthony L.,Orru, Romano V. A.
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p. 3759 - 3762
(2007/10/03)
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- UREAS IN ORGANIC SYNTHESIS. V. REACTIONS OF AROMATIC KETONES AND 1,2-DIKETONES WITH UREAS IN FORMIC ACID
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Urea in formic acid is a general and practical reagent for the reductive aminoformylation of benzophenones and fluoren-9-one in the synthesis of N-diarylmethylformamides, which exhibit antispasmodic activity.With benzophenone in formic acid 1,3-dimethylurea gives a high yield of N-methyl-N-benzhydrylformamide.Urea reacts selectively with benzil and benzoin, forming both the bicyclic bisurea and monocyclic nitrogen-containing heterocycles, depending on the temperature.It was proposed for the first time to use arylmethylenebisureas as reagents in reaction with benzil for the production of 1,5-diphenyl-2,4,6,8-tetraazabicyclooctane-3,7-dione or 2,4,5-triphenylimidazole.
- Bakibaev, A.A.,Yagovkin, A.Yu.,Filimonov, V.D.
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p. 1326 - 1331
(2007/10/02)
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