ortho-[1-(p-MeOPhenyl)vinyl]benzoate PMPVB as a recyclable auxiliary for C–O and C–S bond formation reactions under Brønsted acid catalysis

A practically simple and useful method is reported for the synthesis of ethers and thioethers via Brønsted acid-catalyzed activation of ortho-[1-(p-MeOphenyl)vinyl]benzoate (PMPVB) donors derived from alcohols. The mechanism of action is based on the remote activation of an active alkene followed by intramolecular 5-exo-trig cyclization leading to a reactive intermediate that can react via a substrate dependent SN1 or SN2 mechanism with alcohols and thiol nucleophiles providing facile access to ether and thioether functionalities, respectively.