A thermosetting composition having: I. a curable polyester resin containing beta-ketoacetate moieties without vinyl unsaturations; and II. a phenolic resin having at least one methylol group. The curable polyester resin can be made by reacting a polyester resin with a compound containing a beta-ketoacetate moiety that does not contain a vinyl unsaturation such as alkyl acetoacetate compounds or diketene compounds.The curable polyester resin can be dispersed in water or dissolved in a solvent and is suitable for waterborne or solventborne coating compositions. Phenolic based crosslinking coating compositions that contain these curable polyester resins cure well with phenolic resin crosslinking compounds.