Formylation / Electron-rich Olefin

The present reagent 1 "electron-rich" olefin which reacts with active methylene compounds to form α-substituted aminals 2. The aminal can be converted into an α-substituted aldehyde by hydrolysis. In the reaction with phenol 3, aminal 4 is produced, and p-formylphenol is then formed by hydrolysis. Consequently, this reagent 1 is used as a formylating agent for active methylene or phenols under mild conditions.