- Silver-Catalyzed Chemoselective [4+2] Annulation of Two Isocyanides: A General Route to Pyridone-Fused Carbo- and Heterocycles
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A silver-catalyzed chemoselective [4+2] annulation of aryl and heteroaryl isocyanides with α-substituted isocyanoacetamides was developed for the facile and efficient synthesis of 2-aminoquinolones, naphthyridines, and phenanthrolines. A mechanism for this multistep domino reaction is proposed on the basis of a13C-labeling experiment, according to which an unprecedented chemoselective heterodimerization of two different isocyanides generates an α-amidoketenimine intermediate, which undergoes 1,3-amino migration to form an α-imidoylketene, followed by 6 π electrocyclization.
- Hu, Zhongyan,Dong, Jinhuan,Men, Yang,Lin, Zhichen,Cai, Jinxiong,Xu, Xianxiu
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supporting information
p. 1805 - 1809
(2017/02/05)
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- Synthesis of tetrazolodiazepines by a five-centered four-component azide Ugi reaction. Scope and limitations
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Tetrazolo[1,5-a][1,4]benzodiazepines were obtained by an efficient azide five-centered four-component Ugi reaction, which used ketones, sodium azide, ammonium chloride, and the corresponding isonitrile. Scope and limitations of this multi-component reaction were considered.
- Borisov,Polyakov,Medvedeva,Guranova,Voskressensky
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p. 1609 - 1615
(2013/11/19)
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- The multicomponent approach to N-methyl peptides: Total synthesis of antibacterial (-)-viridic acid and analogues
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Two syntheses of natural viridic acid, an unusual triply N-methylated peptide with two anthranilate units, are presented. The first one is based on peptide-coupling strategies and affords the optically active natural product in 20% overall yield over six steps. A more economical approach with only four steps leads to the similarly active racemate by utilizing a Ugi four-component reaction (Ugi-4CR) as the key transformation. A small library of viridic acid analogues is readily available to provide first SAR insight. The biological activities of the natural product and its derivatives against the Gram-negative bacterium Aliivibrio fischeri were evaluated.
- Neves Filho, Ricardo A. W.,Stark, Sebastian,Westermann, Bernhard,Wessjohann, Ludger A.
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p. 2085 - 2090
(2013/02/22)
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- ortho-Lithiophenyl isocyanide: A versatile precursor for 3H-quinazolin-4-ones and 3H-quinazolin-4-thiones
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(Chemical Equation Presented) ortho-Lithiophenyl isocyanide has been generated from ortho-bromophenyl isocyanide and successfully employed toward the synthesis of 2-substituted phenyl Isocyanides as well as 2,3-disubstituted 3H-quinazoline-4-ones and 3H-q
- Lygin, Alexander V.,De Meijere, Armin
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supporting information; experimental part
p. 389 - 392
(2009/09/05)
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- Synthesis of 4-hydroxy-3-quinolinecarboxylic acid derivatives by a condensation/cyclization sequence between o-isocyanobenzoates and magnesium enolates
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Addition of magnesium ester and amide enolates, generated using an excess amount of a magnesium amide (from diisopropylamine and ethylmagnesium bromide), to o-isocyanobenzoates affords 4-hydroxy-3-quinolinecarboxylic esters and amides by a tandem Claisen-type condensation/cyclization sequence.
- Kobayashi, Kazuhiro,Nakashima, Toshio,Mano, Masaaki,Morikawa, Osamu,Konishi, Hisatoshi
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p. 602 - 603
(2007/10/03)
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