186
S.R. Sterlin, V.A. Grinberg / Journal of Fluorine Chemistry 122 (2003) 183–187
gave product III (in the form of 2 diastereoisomers, bp 65–
67 8C/1 mm, 14.5 g, 52%), current efficiency 40%. Analy-
sis: calc. for C9F12O6S2: C, 21.77; F, 45.97; S, 12.90%.
Found: C, 22.05; F, 45.74; S, 12.67%. 19F NMR (III):
À128.0 and À125.7 (1F4 þ 1F5); 1.1 (3F3); 38.4 and 40.5
(1F1); 60.8 (2 o-F); 61.5 (1F2); 64.0 (1 p-F); 83.5 (2 m-F).
19F NMR: 5:3 þ 5:35 (3F1); 25:2 þ 31:2 (AB-system),
J(AB) ¼ 235 Hz (2F2); 57.0 (1F3); 64:5 þ 68:7 (2 o-F);
83:6 þ 84:4 (2 m-F).
3.4. Reaction of bis(fluorosulfate) III with
AcONa/AcOH
The second fraction a mixture of trifluorosulfates VI–VII
and tetrafluorosulfate VIII (VI:VII:VIII ꢀ 3:1:3) (GC–
MS). MS (m/z, species, intensity, %) (VI): 576 [M]þ 20;
297 [C7F7O3S]þ 45; 214 [C7F6O]þ 50; 195 [C7F5O]þ 100;
186 [C6F6]þ 20; 167 [C3F5O]þ 10; 149 [C3F5O]þ 15; 83
[C9F8O]þ 8.
MS (m/z, species, intensity, %) (VII): 614 [M]þ 5; 595
[M À F]þ ?; 515 [M À FSO3]þ 30; 496 [C9F12O6S2]þ 100;
415 [C7F9O6S2]þ 50; 397 [C9F11O3S]þ 30; 347 [C8F9O3S]þ
50; 295 [C9F9O]þ 25; 267 [C8F9]þ 85; 248 [C8F8]þ 75; 217
[C7F7]þ 100; 198 [C7F6]þ 20; 179 [C7F5]þ 35; 167 [C6F5]þ
10; 149 [C3F5O]þ 65; 117 [C5F3]þ 10; 83 [SO2F]þ 90; 69
[CF3]þ 35; 47 [COF]þ 70.
Bisfluorosulfate III (13 g, 0.026 mol) was gradually
added to a mixture of AcONa (5 g, 0.061 mol) and AcOH
(25 ml); the resulting mixture was stirred at 70–80 8C until
gas liberation was completed, and poured into water, acid-
ified with 30% H2SO4, and extracted with Et2O. The extract
was concentrated, the residue was distilled over H2SO4 to
collect a fraction with bp 70–90 8C/35 mm (5.8 g). Redis-
tillation gave a-diketone (IX) (5.4 g, 70%, bp 76–78 8C/
33 mm), which was identified by comparison with an
authentic sample [13].
3.5. Reaction of diketone IX with CsF
MS (m/z, species, intensity, %) (VIII): 694 [M]þ 14; 595
[M À FSO3]þ 52; 495 [C7F9O9S3]þ 52; 393 [C7F7O7S2]þ
30; 313 [C7F7O4S)]þ 20; 297 [C7F7O3S]þ 30; 214 [C7F6O]þ
20; 195 [C7F5O]þ 30; 183 [C6F5O]þ 30; 97 [C2F3O]þ 25; 83
[SO2F]þ 100; 69 [CF3]þ 40; 51 [CF2H]þ 35.
A mixture of diketone IX (4.3 g, 0.0137 mol), CsF (0.7 g),
and tetraglyme (2 ml) was heated to 120 8C with stirring.
Volatile products with bp up to 70 8C/1.5–2 mm were dis-
tilled off and collected in a trap (À78 8C). Redistillation
gave perfluoro-2-methyl-3-oxobenzoxolene VIII (3.2 g,
75%, bp 170–172 8C). IR(n, cmÀ1): 1515, 1555, 1575, 1785.
3.2. Electrolytic oxidation of perfluoropropenylbenzene
(IV) in HSO3F
A mixture of compound IV (3 g, 10.1 mmol), HSO3F
(17 g), and KSO3F (0.5 g) was electrolyzed on a Pt anode
(2 cm2) using a steel cathode (0.5 cm2) in a one-compart-
ment cell at working potential 2.2 V (versus Cu/Cu2þ refer-
ence electrode) and at 25–28 8C. After 1995 Coul were
passed, the electrolyte was worked up as described in the
previous experiment and distillation gave product III, bp
64–68 8C/1–1.5 mm (3.5 g); (the starting IV (0.3 g) was
condensed in a trap). The chemical yield of III was 78%
on the basis of IV that reacted; current efficiency was 89%.
19F NMR: 6.2 br.d (3F1); 58 br.q (1F2), JðF1ÀF3Þ ¼
5:8 Hz; 57:5 þ 59:7 (2 o-F); 83:6 þ 84:2 (2 m-F). Found:
C, 36.95; F, 52.16. Calculated for C9F8O2: C, 36.98; F,
52.05%.
3.3. Reaction of bisfluorosulfate III with CsF
References
A mixture of compound III (3.2 g, 0.065 mol), CsF (1.4 g,
0.092 mol), and tetraglyme (1 ml) was heated to 125 8C with
stirring for 1 h. Volatile products (70 8C/1.5–2 mm) were
distilled off and collected in a trap (À78 8C); redistillation
gave perfluoro-2-methylbenzoxolene X (1.85 g, 91%, bp
74–76 8C/70 mm. Found: C, 34.71; F, 59.61. Calculated
for C9F10O: C, 34.39; F, 60.51%.
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