A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch, Russian Academy of Sciences, 1 Favorsky Str., 664033 Irkutsk, Russian Federation.
Org Lett. 2013 May 3;15(9):2322-4. doi: 10.1021/ol400844x. Epub 2013 Apr 25.
1-Substituted imidazoles undergo exceptionally facile stereoselective ring opening under the influence of electron-deficient acetylenes and water (equimolar ratio of the reactants) in MeCN at 45-60 °C without any catalysts to afford functionalized (Z,Z)-1,4-diaza-2,5-dienes, (Z,Z)-propenylaminoethenylformamides, in up to 80% yields. The reaction is rationalized to proceed in a tandem manner via zwitterionic vinyl carbanions formed by nucleophilic addition of imidazole to the triple bond. The carbanionic center is then quenched with water followed by the rearrangement of the intermediate 2-hydroxy-3-alkenylimidazolines.
1-取代咪唑在电子缺电子炔烃和水（反应物等摩尔比）的影响下，在 MeCN 中于 45-60°C 下非常容易进行立体选择性开环反应，无需任何催化剂即可提供功能化的（Z,Z）-1,4-二氮杂-2,5-二烯和（Z,Z）-丙烯基氨基乙烯基甲酰胺，产率高达 80%。该反应通过咪唑对三键的亲核加成形成两性离子乙烯基碳负离子进行串联反应。然后，碳负离子中心与水猝灭，接着中间体 2-羟基-3-烯基咪唑啉发生重排。
