Intramolecular Benzyne-Phenolate [4+2] Cycloadditions.

An intramolecular benzyne-phenolate [4+2] cycloaddition is reported. Benzyne precursors, having vicinal halogen-sulfonate functionalities, linked with a phenol(ate) by various tether groups undergo efficient intramolecular [4+2] cycloaddition by treatment with either Ph MgLi or nBuLi for halogen-metal exchange to form various benzobarrelenes.