DMDO epoxidation of bromoallenes gives directly α, β-unsaturated carboxylic acids under the reaction conditions. Calculated (ωB97XD/6-311G (d, p)/SCRF= acetone) potential energy surfaces and 2H-and 13C-labeling experiments are consistent with bromoallene oxide intermediates which spontaneously rearrange via a bromocyclopropanone in an intersecting bromoallene oxide–Favorskii manifold.
