Are there alternatives to 3,4-Dihydro-2H-pyran-6-carboxylic acid in synthesis?

Several alternatives to 3,4-Dihydro-2H-pyran-6-carboxylic acid (CAS: 31518-14-6) exist in chemical synthesis, such as other carboxylic acids, pyrano[2,3-d]pyran derivatives, and related compounds. Isomers and analogs can be used depending on the specific requirements of the synthesis. Common alternatives include 4-hydroxy-3,4-dihydro-2H-pyran-6-carboxylic acid and 3,4-dihydro-2H-pyran-4,6-dicarboxylic acid, which can provide similar functionalities with varying reactivity and solubility.