The epoxides of the type 4 undergo ring-opening with carbanions; without exception, the nucleophiles attack at C-1 in spite of the increased steric hindrance at the site (as in epoxides 4b and 4e having peri-substituents). Interaction of the epoxide 4b with the anion of diethyl methylmalonate in refluxing t-butanol afforded, besides other products, the novel cyclopropane carboxylic acid 12. What is more significant is that although the formation of ...
