Revised mechanism and improved methodology for the Perkin condensation. Resuscitation of the mechanism involving benzal acetate and the improbability of the enolate of acetic anhydride

The Perkin condensation most likely occurs via the initial formation of a gem-diacetate from the aromatic aldehyde and acetic anhydride reactants. The key reactive nucleophile appears to be the enolate of the gem-diacetate rather than of acetic anhydride. The diacetate from PhCHO may be converted to cinnamic acid under a variety of (relatively) mild basic conditions.