"Reaction of the stabilized anions derived from β-dicarbonyl compounds and related analogs with α,β-unsaturated carbonyl compounds leads to 1,4-additions. This trans formation, an example of Michael addition, is base-catalyzed and works with α,β-unsaturated ketones, aldehydes, nitriles, and carboxylic acid derivatives, all of which are termed Michael acceptors. (...) β-Dicarbonyl anions, like ordinary enolate anions, undergo Michael additions to α,β-unsaturated carbonyl compounds. Addition of a β-ketoester to an enone gives a diketone, which can generate six-membered rings by intramolecular aldol condensation (Robinson annulation)."