The [3+2] Cycloaddition of Diphenyldiazomethane and Ethyl Diazoacetate with Itaconic Anhydride. A New Access to Spiranic Cyclopropane Derivatives †

Abstract

The reaction of itaconic anhydride 1 with ethyl diazoacetate 2 or diphenyldiazomethane 5 gave the expected spiroderivatives, which spontaneously rearranged; specifically, the adduct from 1 and 5 loses a dinitrogen molecule, yielding a spirocyclopropane related to the known 5-azaspiro[2.4]heptane-4,6-diones or 5-azaspiro[2.4]heptanes.