American Chemical Society
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Stereoselective C(2)-Vinylation of 1-Substituted Imidazoles with 3-Phenyl-2-propynenitrile

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journal contribution
posted on 2008-11-21, 00:00 authored by Boris A. Trofimov, Lyudmila V. Andriyankova, Kseniya V. Belyaeva, Anastasiya G. Mal’kina, Lina P. Nikitina, Andrei V. Afonin, Igor A. Ushakov
First examples of direct vinylation of 1-substituted imidazoles at the 2-position of the imidazole nucleus are described. 1-Substituted imidazoles 1a−e are C(2)-vinylated with 3-phenyl-2-propynenitrile (2) at room temperature without catalyst and solvent to afford 3-(1-organyl-1H-imidazol-2-yl)-3-phenyl-2-propenenitriles 3a−e, mainly (c.a. 95%) as (Z)-isomers, in 56−88% yield. The reaction is likely to involve the zwitterionic intermediates, which prototropically isomerizes to imidazole carbene and eventually undergoes the selective 3,2-shift of the functionalized vinyl substituent.