## 3 Results and Discussion
### Synthesis of Perfluorobis(alkanesulfonyl) Monomer (Scheme 4)  
To date, the method to prepare perfluorobis(sulfonyl) compounds has been very limited. [PERSON] and [PERSON] reported fluorobis(fluorosulfonyl)acetyl fluoride, (FSO\({}_{2}\))\({}_{2}\)CFCOF [14]. The yield of  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Material** & **Water (deg.)** & **n-Hexadecane (deg.)** & **friction coefficient** \\ \hline
**3** & 108 & 71 & 0.159 \\
**1a** & 105 & 65 & 0.184 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Contact angle and friction coefficient of coating glass.  
Figure 1: Abrasion Resistance Test.  
this compound, however, was low, and it easily decarbonylated in the presence of fluoride ions. Instead of employing this method, we adopted a totally different approach, which includes the PERFECT process as a key step. It enabled us to build the perfluorinated backbone structure with two fluorosulfonyl groups and one fluorocarbonyl group from a non-fluorinated sulfonyl compound prepared by organic synthesis. Then, the introduction of a polymerizable trifluorovinyloxy group was carried out using hexafluoropropene oxide. Our method seemed not to have the problem described above, since the fluorocarbonyl group reacts with hexafluoropropene oxide prior to decarbonylation. The synthetic path to **4** is shown in Scheme 4.  
**Scheme 4.** Synthesis of perfluorobis(alkanesulfonyl) monomer **4**.  
Compound **11** was prepared by a nucleophilic attack of \(\alpha\)-toluenethiol to epichlorohydrin [15]. Allylation of the hydroxy group (allyl bromide-NaH-THF, 0 \({}^{\circ}\)C, 1 h, then 25 \({}^{\circ}\)C, 20 h) produced **12**[16]. Hydroboration-oxidation was performed to the double bond of **12** (1.icyclohexylborane-THF,0 \({}^{\circ}\)C, 19 h; 2. NaOH aq. then 30% H\({}_{2}\)O\({}_{2}\)) to furnish **13**. When the borane/THF complex was used as the hydrocarbon reagent, the unwanted secondary alcohol (2\({}^{\circ}\)-ol) was formed with the desired **13** (**13**: 2\({}^{\circ}\)-ol = 69:31). Using the more sterically hindered dicyclohexylborane as the borane reagent essentially eliminated 2\({}^{\circ}\)-ol [17]. The compound **13** was condensed with perfluoro-2,5-dimethyl-3,6-dioxanonaoyl fluoride (**6**) (triethylamine-dichloromethane, 0 \({}^{\circ}\)C, 1 h, then 25 \({}^{\circ}\)C, 3 h) to afford the ester **14**. Oxidation of **14** by chlorine (acetic acid-water, 25 \({}^{\circ}\)C, 16 h) [18], followed by treatment with KHF\({}_{2}\) (acetonitrile-water, 25 \({}^{\circ}\)C, 24 h) provided the sulfonyl fluoride **16**[19]. The PERFECT process was applied to **16** (1. 20% F\({}_{2}\)/N\({}_{2}\)-trichlorotrifluoroethane, 20 \({}^{\circ}\)C, 1.5 h; 2. KF, 90 \({}^{\circ}\)C, 1.5 h) to furnish **18**[8]. The reaction of **18** with hexafluoropropene oxide (CsF-diglyme, 0 \({}^{\circ}\)C, 1 h) proceeded to obtain **19**, which was decarbonylated (1. KHCO\({}_{3}\)-glyme, 0 \({}^{\circ}\)C, 0.5 h; 2. 120 \({}^{\circ}\)C, 3 h, then 200 \({}^{\circ}\)C, 1 h) to afford the desired **4**[20].  
The overall yield of **4** was as low as 2%, the net result of several low yield steps. The single lowest yield was the fluorination step. C-S bond disconnection occurred as in the case of the fluorination of other C-S bond containing substrates [11]. The typical yields of the fluorination of the substrates with one C-S bond have been 60-70%. The substrate **16**, however, has two C-S bonds so that there is a high chance of the disconnection compared with substrates with one C-S bond. The introduction of sulfur into fluorinated molecules should be reconsidered.  
The yields of the steps after the fluorination were also low. They could be improved after optimizing the reaction conditions.