Additionen an die Dreifachbindung, XI. Struktur und Reaktionen des 2:1‐Adduktes aus Acetylendicarbonester und Isonitrilen

Abstract

H Das unpolare 2 : I-Addukt von Acetylendicarbonester und lsonitrilen wird als ein Abfangprodukt des Primar-Dipols 1 mit der Carbonyldoppelbindung eines zweiten Estermolekiils erkannt (4). Im Zuge der chemischen Umwandlungen dieser Furanderivats IaiRt sich ein stabiles Ketenimin (13) isolieren und charakterisieren.Aus einer groljen Zahl von Reaktionenz), speziell aus der naher von Ugi untersuchten Umsetzung mit Imoniumsalzen, geht hervor, daD Isonitrile als nucleophile Reaktionspartner wirksam werden konnen. Setzt man das Isonitril mit der acceptorsubstituierten Dreifachbindung des Acetylendicarbonesters um, so ware mit dem primaren 1.3-Dip01 1 zu rechnen. COZCH3 COzCH, R-N=C$COzCH3COzCH3 C0,CHs COZCH3 e-+ R-N=C& @ a'\ # R-N<

A modified and green methodology for preparation of polysubstituted furans

“…Of the simplest and the most interesting report is the procedure which is based on three-component reaction of alkyl isocyanides, dialkyl acetylendicarboxylates, and aromatic aldehydes [7]. The addition of nucleophilic carbenes such as isocyanides to dimethyl acetylenedicarboxylate (DMAD) has been investigated in detail [11]. Furans with different substituents have been formed from the reaction of initially formed 1:1 zwitter ionic species I (Fig.…”

One-pot, three component reactions between isocyanides and dialkyl acetylenedicarboxylates in the presence of phenyl isocyanate: synthesis of dialkyl 2-(alkyl/arylimino)-2,5-dihydro-5-oxo-1-phenyl-1H-pyrrole-3,4-dicarboxylate

“…[6][7] The reactivity of nucleophilic carbenes such as isocyanides towards dimethyl acetylenedicarboxylate (DMAD) is well documented. [8][9][10] The reaction of isocyanides with carbon-carbon triple bonds occurs in a stepwise manner through a zwitterionic intermediate, the ultimate fate of which appears to be dictated by the nature of original triple-bonded substrate. [11][12][13][14][15][16][17][18][19] In continuation of our interest in the application of isocyanides in heterocyclic synthesis, [20][21][22][23][24][25][26][27] we now report the reaction between alkyl/aryl isocyanides 1 and dialkyl acetylenedicarboxylate 2 in the presence of phenyl isocyanate.…”

Isoquinoline-catalyzed reaction between 4-hydroxycoumarin or 4-hydroxy-6-methylpyran-1-one and dialkyl acetylene dicarboxylates: synthesis of coumarin and pyranopyrane derivatives

“…[5][6][7][8][9][10][11] These zwitterions intermediate can be trapped with a variety of electrophiles and proton donors, which is a novel protocol for the synthesis of heterocyclic compounds. [5][6][7][8][9][10][11][12][13] Trapping of the zwitterion formed by the addition of isoquinoline to dimethyl acetylenedicarboxylate (DMAD) with electrophiles such as isocyanates, 14 N-tosylimines, 15 quinines 16 and electrophilic styrenes, 17 has been recently used for the synthesis of different isoquinoline-fuzed heterocyclic systems. Reaction of electron-deficient acetylene esters with isoquinoline or quinoline has been also studied in the presence of organic acidic compounds.…”