Highly Efficient Syntheses of beta-Cyanoketones via Conjugate Addition of Me3SiCN to Aromatic Enones

An efficient 1,4-addition of Me3SiCN to aromatic enones has been achieved with excellent yields (91%-99%) using CsF (1 mol%) as the catalyst and H2O (4 equiv.) as the additive in refluxing dioxane within 7 h. The perfect regioselectivity is proposed accounting from H2O-facilitated reversion of the 1,2-adduct in the presence of CsF and subsequent irreversible 1,4-addition reaction.