26  US 8,283,102 B2  25  $^{1}$H-NMR (chloroform-d3, reference: tetramethylsilane):  (ppm) 4.98 (t, 2H), 7 .05 ( d, 2H), 7 .38-7 .78 (m, 15H), 8.12 ( d,  2H),  ester diphenyl-4-methacroyloxy-phenylsulfonium salt, and a  structure of the heptanoic acid-2,2-difluoro-2-sulfo-ethyl  ester diphenyl-4-methacroyloxy-phenylsulfonium salt was  observed by $^{1}$H-NMR (see FIG. 7):  $^{1}$H-NMR (chloroform-d3, reference: tetramethylsilane):  (ppm) 0.83 (t, 3H), 1.32 (m, 6H), 1.61 (m, 2H), 1.38 (t, 2H),  2.05 (s, 3H), 4.78 (t, 2H), 5.83 (s, lH), 6.40 (s, lH), 7.51 (d,  2H), 7.65-7.78 (m, !OH), 7.85 (d, 2H),  About 4.3 g of the benzoic acid-2,2-difluoro-2-sulfo-ethyl  ester diphenyl-4-hydroxyphenylsulfonium salt manufactured  in the synthesis example 9, about 0.81 ml of methacryloyl  chloride, and about 9.7 mg of 4-methoxyphenol (MEHQ)  were mixed and stirred in about 150 ml ofan MC, about 2.1  ml of diisopropylethylamine (DIPEA) was gradually dropped  using a dropping funnel under an ice bath, and a synthesis  reaction (see Equation 10 below) was performed while stir› ring about three hours at room temperature. In this instance,  4-dimethylaminopyridine (DMAP) was used as a reaction  catalyst, and a process of the synthesis reaction was observed  by $^{19}$F NMR using a small amount of an extracted organic  phase. The organic phase was extracted when the synthesis  reaction was terminated, and washed using IN HCl, distilled  water, a saturated sodium bicarbonate aqueous solution, and  distilled water in the stated order (three times).  Next, a solvent was removed, and washing with the MC of  a soluble solvent and hexane of a sparingly soluble solvent  was performed. Next, the solvents were removed, and drying  under a reduced pressure was performed to obtain about 3.87  g (a yield: about 80%) ofa benzoic acid-2,2-difluoro-2-sulfo› ethyl ester diphenyl-4-methacroyloxy-phenylsulfonium salt,  and a structure of the benzoic acid-2,2-difluoro-2-sulfo-ethyl  About 6 g of the diphenyl-4-hydroxyphenylsulfonium tri› fluoromethanesulfonate salt manufactured in the synthesis  example 3 and about 4.84 g of a benzoic acid-2,2-difluoro-2- sulfo-ethyl ester sodium salt were dissolved in about 100 ml  of an MC and about 100 ml of water, and a synthesis reaction  ( see Equation 9 below) was performed while strongly stirring  for about three hours. In this instance, a process of the syn› thesis reaction was observed by $^{19}$F NMR using a small  amount of an extracted organic phase. The organic phase was  extracted when the synthesis reaction was terminated, and  washed using the MC of a soluble solvent and hexane of a  sparingly soluble solvent. Next, the solvents were removed,  and drying under a reduced pressure was performed to obtain  about 4.3 g (a yield: about 56.4%) of a benzoic acid-2,2- difluoro-2-sulfo-ethyl ester diphenyl-4-hydroxyphenylsulfo› nium salt, and a structure of the benzoic acid-2,2-difluoro-2- sulfo-ethyl ester diphenyl-4-hydroxyphenylsulfonium salt  was observed by $^{1}$H-NMR (see FIG.  8):  Benzoic acid-2,2-difluoro-2-sulfo-ethyl Ester  Diphenyl-4-hydroxyphenylsulfonium Salt Synthesis  Synthesis Example 9  Synthesis Example 10  Benzoic acid-2,2-difluoro-2-sulfo-ethyl Ester  Dipheny 1-4-methacroy loxy-pheny lsulfonium Salt  Synthesis  Qo  ~  0  0-¢s+_o-ri-cF 3  ~  I  OH  0  0  Na+_o,....,...fi’-c~o~  0 F2  I  #  MC/DW  Q"  0  ~I  OH  [Equation 9]  0- C? ✓L-o~  ¢  0 ,,  ’  OH  1) DIPEA, 2) DMAP  3)MEHQ  [Equation 8] 