[{"from": "human", "value": "Generate a molecule based on the given description. The molecule is the L-enantiomer of threitol. It has a role as an algal metabolite. It is an enantiomer of a D-threitol."}, {"from": "gpt", "value": "[C][Branch1][O][C@@H1][Branch1][#Branch1][C@H1][Branch1][Ring1][C][O][O][O][O]"}]