Cyclization Of 2-alkynylanilines Research Articles

Base-Promoted Tandem Synthesis of 2-Substituted Indoles and N-Fused Polycyclic Indoles.

Herein is developed a base-promoted approach for the synthesis of C2-substituted indoles and N-fused polycyclic indoles via 5-endo-dig cyclization of 2-alkynyl anilines, followed by a 1,3'-acyl migration or a dearomatizing Michael addition process. A range of N-H free indoles and 8,9-dihydropyrido[1,2-a]indol-6(7H)-one scaffolds were synthesized in good to excellent yields with broad scope.

Solvent-Dependent Cyclization of 2-Alkynylanilines and ClCF2COONa for the Divergent Assembly of N-(Quinolin-2-yl)amides and Quinolin-2(1H)-ones.

Herein, we present an expedient Cu-catalyzed [5 + 1] cyclization of 2-alkynylanilines and ClCF2COONa to divergent construction of N-(quinolin-2-yl)amides and quinolin-2(1H)-ones by regulating the reaction solvents. Notably, nitrile acts as a solvent and performs the Ritter reactions. ClCF2COONa is used as a C1 synthon in this transformation, which also represents the first example for utilization of ClCF2COONa as an efficient desiliconization reagent. The current protocol involves in situ generation of isocyanide, copper-activated alkyne, Ritter reaction and protonation.

Synthesis of polyfluorinated 4‑hydroxyquinolin-2(1H)‑ones based on the cyclization of 2-alkynylanilines with carbon dioxide

Convenient and efficient synthesis of polyfluorinated 4-hydroxyquinolin-2(1H)-ones from the corresponding o-alkynylaniline derivatives and CO2 (1 atm), mediated by 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and AgNO3 in acetonitrile was performed. This synthetic methodology may be used to prepare fluorinated heterocycles containing peripheral alkynyl and amino groups but is not suitable for silylethynyl derivatives that give indoles as the main products. The reaction takes place under mild conditions (60 °C) and involves readily available starting materials that include cheap and renewable carbon dioxide.

Molecular-Iodine-Catalyzed Cyclization of 2-Alkynylanilines via Iodocyclization-Protodeiodination Sequence.

Molecular iodine catalyzes a cyclization of N-aryl-2-alkynylanilines, which proceeds through the iodocyclization of 2-alkynylanilines followed by the protodeiodination of the iodocyclized intermediates at room temperature. Furthermore, the molecular iodine catalysis can be applied to the cascade cyclization of 2-(enynyl)aniline and to the tandem cyclization-addition reaction of 2-alkynylanilines with α,β-enones.

ChemInform Abstract: [Cp*IrCl2]2‐Catalyzed Cyclization of 2‐Alkynylanilines into Indoles.

AbstractFor the formation of 2‐trimethylsilylindole a slight modification of the conditions is required.

Electrochemical Cyclization of 2-Alkynylanilines to Indole Derivatives

Electrochemical Cyclization of 2-Alkynylanilines to Indole Derivatives

Gold-Catalyzed Synthesis of 2-Substituted, 2,3-Disubstituted and 1,2,3-Trisubstituted Indoles in [bmim]BF4

Cyclization of 2-alkynylanilines in the presence of NaAuCl4·H2O using [bmim]BF4 as the reaction medium afforded 2-substituted indoles in high yields. The catalyst system was best recycled using n-Bu4NAuCl4. 2,3-Disubstituted indoles could be prepared from 2-alkynylanilines and 3-buten-2-one through a one-flask annulation-alkylation sequence and 1,2,3-trisubstituted indoles were obtained from the same starting materials via an aza-Michael addition-annulation-alkylation process.