C(2)-Functionalization of 1-substituted imidazoles with cyanoacetylenes and aromatic or heteroaromatic aldehydes

• Published in: Tetrahedron Vol. 67; no. 6; pp. 1288 - 1293
• Main Authors: Trofimov, Boris A., Andriyankova, Ludmila V., Belyaeva, Kseniya V., Mal’kina, Anastasiya G., Nikitina, Lina P., Dyachenko, Oleg A., Kazheva, Olga N., Alexandrov, Grigorii G., Shilov, Gennadii V., Afonin, Andrei V., Ushakov, Igor’ A.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 11-02-2011
• Subjects: 1-Substituted imidazoles; Aldehydes; Aliphatic compounds; Benzaldehyde; Cyanoacetylenes; Derivatives; Ethers; Imidazole; Multicomponent reaction; Solvents; Tetrahedrons; 1-Substituted imidazoles; Cyanoacetylenes; Multicomponent reaction; Aldehydes
• ISSN: 0040-4020; 1464-5416
• DOI: 10.1016/j.tet.2010.11.072

Substituted imidazoles (substituents are Me, Et,
i-Bu,
n-Hexyl, (CH
2)
2S–Bu-
n, Ph, Bn) react smoothly (room temperature, without catalyst and solvent) with cyanoacetylenes (3-phenyl-2-propynenitrile and 4-(1-butoxyethoxy)-4-methyl-2-pentynenitrile) and aromatic or heteroaromatic aldehydes (benzaldehyde, 4-CN-benzaldehyde, pyridine-3-aldehyde) to give 3-(2-imidazolyl)-3-aryl-2-acylpropanenitriles, a hitherto unknown family of functionalized imidazole derivatives, in up to 62% yield. This three-component manifold represents a novel
C(2)-functionalization of the imidazole nucleus involving zwitterionic, carbene and enol ether intermediates. Unlike the analogous reaction with aliphatic aldehydes, which gives enol ethers, in this case the latter undergo the further rearrangement to 3-(2-imidazolyl)-3-aryl-2-acylpropanenitriles.
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