Abstract Cycloadditions of 2-cyclopropylidene-1, 3-dimethylimidazolidine (1), a strong, electron-rich C-nucleophile, with a variety of aryl-substituted 1, 2, 4-triazines occur at temperatures between− 100 and+ 100, depending on the substitution pattern. At low temperatures, zwitterions, formed by nucleophilic attack of 1 on the triazines, could be detected spectroscopically and, in some cases, isolated. Two types of zwitterions were ...
