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 S N 1 or S N 2 mechanism with alcohols and thiol nucleophiles providing facile access to ether and thioether functionalities, respectively.