Metalation of o-Halostyrene Oxides. Preparation of Benzocyclobutenols

Article abstract of DOI:10.1021/jo00326a026

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 deg 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.