Abstract γ-Methylene derivatives of α,β-unsaturatedketones are obtained readily by a one-pot procedure exploiting the reaction of O-silylated dienolates with commercially available formaldehyde N, N-dimethyliminium chloride in anhydrous N, N-dimethylformamide, in situ oxidation of the Mannich reaction product with hydrogenperoxide, and elimination of N,N-dimethylhydroxylamine from the resultant N-oxide