On the purported synthesis of a bicyclo[2.2.1]heptene diester by reaction of diazomethane with dimethyl 1,3-cyclohexadiene-1,4-dicarboxylate

Addition of diazomethane to dimethyl 1,3-cyclohexadiene-1,4-dicarboxylate, followed by thermolysis at 140°C, had been reported to yield a bicyclo[2.2.1]heptene diester. This report is not correct. The products are now shown to be a diene diester, a cyclopropane and an exo-methylene diester.