Approaches to the synthesis of 5-spirocyclopropyldihydroorotic acid are described. Difficulties were encountered in the lack of reactivity of diethyl 2-oxobutandicarboxylate and its derivatives towards cyclopropanation. Potential intermediates were prepared from ethyl 4- acetoxy-3-oxobutanoate but rearrangements involving ring expansion of the cyclopropane ring and hindrance towards condensation reactions of the ketone prevented formation of ...