A mild and convenient synthesis of substituted α-methylene-δ-valerolactones was achieved by SN2 nucleophilic substitution of the acetates of Baylis-Hillman adducts with acetyl acetone followed by one-pot saponification of the ester, reduction of the keto group, and subsequent intramolecular ring closure in aqueous medium.
Baylis-Hillman - α-methylene-δ-valerolactone - nucleophilic substitution - aqueous medium