Water Mediated Rearrangement of Alkynyl Cyclohexadienones: Access to meta-Alkenylated Phenols.

We report an efficient water mediated, Brønsted acid-catalyzed rearrangement of alkynyl cyclohexadienones to access meta-olefinated phenols under metal-free conditions. The reaction displayed excellent substrate scope and yields in water. Synthetic utility of the protocol was highlighted by carrying out gram scale synthesis, further functionalizations, and late stage modification. Mechanistic studies highlighted the key role of water, as the reaction proceeds via a water addition-elimination sequence on to a vinyl cation intermediate.