Pd- and Rh-Catalyzed Hydroarylation of γ‑(2-Methoxy­carbonyl­phenyl)­propargylic Alcohols: Approaches to 4- or 5‑Substituted Seven-Membered Benzolactones and 3,3-Disubstituted Phthalides

A study of the palladium-catalyzed hydroarylation/hydrovinylation reaction of γ-(2-methoxy­carbonyl­phenyl)­propargylic alcohols with aryl iodides/vinyl triflates and of the rhodium-catalyzed one with organoboron derivatives is described. The opposite regiochemical outcome of the two processes allows an easy selective approach to 5- or 4-substituted benzoxepin-1­(3H)-ones by combining the hydroarylative/hydrovinylative step with cyclocondensation between −OH and −COOMe groups in the intermediate γ,γ-disubstituted or β,γ-disubstituted allylic alcohols. A one-flask procedure to give benzo­[c]­oxepin-1­(3H)-ones directly from the starting alkyne has been also developed. Treatment of crude γ,γ-disubstituted allylic alcohols with NaOH, followed by acidification, affords 3,3-disubstituted phthalides.