A versatile methodology for the nucleophilic formylation and cyanation of conjugated enones is reported. The procedure is based on the use of formaldehyde dimethylhydrazone, which, acting as a neutral formyl anion equivalent, adds to preformed trialkylsilyl-enone complexes. Both 4-(silyloxy)-3-enal hydrazones 3 or deprotected 4-oxo aldehyde monohydrazones 4 can be obtained as products depending on quenching conditions. In ...