5-Yn-1-ones react with arylboronic acids in the presence of a catalytic amount of rhodium(I) complex having a diolefin ligand to afford 2-alkylidenecyclopentanols through the regioselective addition of an arylrhodium(I) species across the carbon-carbon triple bond, followed by intramolecular nucleophilic addition of the resulting vinylrhodium(I) species to the carbonyl group.