Oxidative cyclization of beta-hydroxyenones with palladium(II): a novel entry to 2,3-dihydro-4H-pyran-4-ones.

[reaction: see text] A palladium(II)-mediated oxidative cyclization was found to be effective for the preparation of structurally diverse 2,3-dihydro-4H-pyran-4-ones from the corresponding beta-hydroxyenones. Attractive features of this transformation include the ready availability of the starting enones, the regiocontrol, and the easy access of enantiopure 2,3-dihydro-4H-pyran-4-one from the corresponding enantiopure enone.