9-anthracenecarbonyloxymethyldifluoromethanesulfonic acid sodium salt 、 、 Diphenylmethylphenylsulfonium trifluoromethanesulfonic acid sodium salt 以produced in <1> of Synthesis Example 9的产率得到9-Anthracenecarboxylic acid 2,2-difluoro-2-sulfoethyl ester diphenylmethylphenylsulfonium salt