[{"from": "human", "value": "Create a molecule that satisfies the conditions outlined in the description. The molecule is the simplest member of the class of delta-lactone that is tetrahydro-2H-pyran substituted by an oxo group at position 2. It derives from a hydride of an oxane."}, {"from": "gpt", "value": "[C][C][C][O][C][=Branch1][C][=O][C][Ring1][#Branch1]"}]