An efficient and mild synthesis of a variety of 3-(2-oxopropyl)-isoindolinone derivatives via a BF3·Et2O catalyzed cascade reaction among 3-hydroxyisoindolin-1-one and phenylacetylene was achieved. Various isoindolinone derivatives were obtained in good to excellent yields. The process, which avoided several drawbacks such as the requirement of concentrated protic acids and metal catalysts, protecting group of nitrogen, high temperature, and multistep synthesis, includes C(sp3)-OH cleavage, C-C coupling, and hydration of alkyne.