If a palladium catalyst is not used, allyl esters rearrange to gamma-delta unsaturated compounds through this intermediate in the Carroll rearrangement, while beta-gamma unsaturated compounds equilibrate when possible with alpha-beta unsaturated compounds with this species as the intermediate. Alkylation of ions of these molecules by an alkyl halide or a tosylate forms carbon-carbon single bonds, and stereochemical information is lost over time in ethylacetoacetate because of the formation of one. While forming one with acid can lead to single halogenation, using base leads to the haloform reaction and the generation of a carboxylate. Enamines may be used as equivalents to this functional group, and they are essential to the Robinson annulation and the Claisen condensation. Malonic acid derivatives form particularly stable ones due to conjugation. For 10 points, 
If a palladium catalyst is not used, allyl esters rearrange to gamma-delta unsaturated compounds through this intermediate in the Carroll rearrangement, while beta-gamma unsaturated compounds equilibrate when possible with alpha-beta unsaturated compounds with this species as the intermediate. Alkylation of ions of these molecules by an alkyl halide or a tosylate forms carbon-carbon single bonds, and stereochemical information is lost over time in ethylacetoacetate because of the formation of one. While forming one with acid can lead to single halogenation, using base leads to the haloform reaction and the generation of a carboxylate. Enamines may be used as equivalents to this functional group, and they are essential to the Robinson annulation and the Claisen condensation. Malonic acid derivatives form particularly stable ones due to conjugation. For 10 points, identify this functional group, the tautomer of many carbonyl compounds.
If a palladium catalyst is not used, allyl esters rearrange to gamma-delta unsaturated compounds through this intermediate in the Carroll rearrangement, while beta-gamma unsaturated compounds equilibrate when possible with alpha-beta unsaturated compounds with this species as the intermediate.
enols