Total synthesis of both enantiomers of 9-methoxystrobilurin L as the originally proposed 1,4-benzodioxan structure was successfully achieved. The 1H and 13C NMR spectra of synthesized 9-methoxystrobilurin L were compared with those of a naturally-occurring sample. It was strongly indicated that naturally-occurring 9-methoxystrobilurin L has not the originally reported 1,4-benzodioxan structure but a 1,5-benzodioxepin structure, the same as previously reported 9-methoxystrobilurin K. Antifungal activities of the synthesized compounds toward several typical fungi were also examined, and they were less active than 9-methoxystrobilurin K.