Metalation of o-Halostyrene Oxides. Preparation of Benzocyclobutenols

O-Bromo- and O-iodostyrene oxides are converted in fair to good yield to benzocyclobutenols upon treatment with n-BuLi and MgBr₂ in THF or ether at -78 °C, followed by warming to room temperature. The reaction involves initial halogen-lithium exchange followed either by MgBr₂-initiated opening of the epoxide function to a haloalkoxide or rearrangement of the epoxide function to a ketone or aldehyde followed by cyclization. Benzocyclobutenol formation was not successful in the case of o-halostilbene oxides.