H.-P. Cao, Q.-Y. Chen / Journal of Fluorine Chemistry 128 (2007) 1187–1190
1189
1
9
or KMnO (2 equiv.) in DMSO or DMSO/H O (vol:vol = 1:1).
4
63 8C/35 Torr). F NMR: d = ꢁ58.7 to ꢁ58.8 (m, 4F),
ꢁ112.1 to ꢁ112.2 (m, 4F) (lit. [23], ꢁ65.0 (t, J = 0.2 Hz,
4F), ꢁ114.4 (t, J = 0.2 Hz, 4F)).
2
The results are listed in Table 1.
Similarly, treatment of disodium sulfinate 3a with iodine
in DMSO at room temperature for 1 h, gave 4a in a low
yield (20%), but it could be improved to 44% in DMSO/H O
4b: Colorless oil. b.p. 102 8C/62 Torr (lit. [23], 80–83 8C/
1
9
15 Torr). F NMR: d = ꢁ56.9 (s, 4F), ꢁ111.0 (s, 4F), ꢁ118.7
(d, J = 43.4 Hz, 4F) (lit. [23], ꢁ65.0 (t, J = 0.2 Hz, 4F), ꢁ115.0
(m, 4F), ꢁ122.4 (m, 4F)).
2
(
vol:vol = 1:1) for 1 h. All the results are listed in
Table 2.
It is noted that compared with ICF CF I, telomerization of
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9
4c: White solid. F NMR: d = ꢁ59.5 (s, 4F), ꢁ113.5 (s, 4F),
ꢁ121.3 (s, 4F), ꢁ122.1 (s, 4F) (lit. [23], ꢁ65.0 (t, J = 0.2 Hz,
4F), ꢁ115.0 (m, 4F), ꢁ123.3 (m, 8F)).
2
2
ICF CF Cl with TFE can be carried out more effectively due to
2
2
the absence of fluorinated radical b-scission [16,17]. Telomers
Cl(CF CF ) I obtained are the starting materials in this work.
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9
4d: Colorless oil. b.p. 115 8C (lit. [24], 117 8C). F NMR:
d = ꢁ59.2 (d, J = 16.4 Hz, 2F), ꢁ80.9 (t, J = 8.0 Hz, 3F),
ꢁ113.2 (s, 2F), ꢁ121.8 (s, 2F), ꢁ122.8 (s, 2F), ꢁ126.2 (s,
2F) (lit. [25], ꢁ59.9, ꢁ82.2, ꢁ114.1, ꢁ122.2, ꢁ123.6,
ꢁ127.3).
2
2 n
They may be first fluorinated with Swartz’s reagent (HF/SbCl5)
to give Cl(CF CF ) F, which can be then converted into
F(CF CF ) I as described above (entries 7 and 8, Table 2). In
2
2 n
2
2 n
this case, there is no need of IF for preparing the commercial
5
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9
TFE-telogen CF CF I [8,9]. On the other hand, the telomers
3
4e: Colorless oil. b.p. 155 8C (lit. [24], 160–161 8C).
F
2
Cl(CF CF ) I may be directly transferred to valuable a,v-
2
diiodoperfluoroalkanes by our method.
NMR: d = ꢁ59.2 (t, J = 15.9 Hz, 2F), ꢁ80.8 (s, 3F), ꢁ113.1 (s,
2 n
2F), ꢁ120.9 (s, 2F), ꢁ121.9 (s, 4F), ꢁ122.7 (s, 2F), ꢁ126.2 (s,
2
F) (lit. [26], ꢁ58.6, ꢁ82.3, ꢁ113.5, ꢁ122.4, ꢁ122.4, ꢁ122.4
3
. Conclusion
(4F), ꢁ126.6)
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4
i: F NMR: d = ꢁ11.5 (s, 3F) (lit. [27], ꢁ3.7 (s, 3F)).
In summary, we have developed a practical and convenient
method for converting Cl(CF CF ) I into F(CF CF ) I or
4.3. Preparation of 1,6-diiodo-1,1,2,2,3,3,4,4,5,5,6,6-
dodecafluorohexane from 1,6-dibromo-
1,1,2,2,3,3,4,4,5,5,6,6-dodecafluorohexane
2
2 n
2
2 n
I(CF CF ) I by modified sulfinatodehalogenation method
2
2 n
(
to other functional groups are underway in our laboratory.
Na S O /DMSO). Further studies on transferring the sulfinates
2
2 4
A mixture of 1,6-dibromo-1,1,2,2,3,3,4,4,5,5,6,6-dodeca-
fluorohexane (1f) (9.20 g, 20 mmol), Na S O (13.92 g,
4
. Experimental
2
2 4
8
temperature for 3 h under nitrogen. The conversion of 1f
0 mmol) and DMSO (50 mL) was stirred at room
4
.1. General
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9
was 100%, determined by F NMR spectra [signals of
19
F
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9
F NMR spectra were recorded at 282 MHz. Chemical
shifts were reported in parts per million relative to CFCl as an
1
external standard (positive for up field shifts) for F NMR. The
NMR at ꢁ121.7 ppm (4F, CF ), ꢁ122.2 ppm (4F, CF ),
2
2
ꢁ130.6 ppm (4F, CF SO Na)]. To the content was added
3
2
2
9
water (50 mL), Na S O (19.04 g, 80 mmol) and iodine
2 2 8
solvent for NMR measurement was CDCl unless otherwise
3
(20.32 g, 80mmol) and allowed to react at room temperature
for another 1 h. The resultant solution was extracted with
ether (3 ꢂ 30 mL). The combined extracts were washed with
saturated sodium thiosulfate (3 ꢂ 30 mL), water (3 ꢂ 20 mL)
and dried over Na SO . After removing ether, the residue
noted. DMSO were distilled from CaH2.
4
.2. Preparation of 1,4-diiodo-1,1,2,2,3,3,4,4-
octafluorobutane from 1-chloro-4-iodo-1,1,2,2,3,3,4,4-
octafluorobutane
2
4
was distilled to give 4b (6.0 g, 54%) as a colorless oil, b.p.
1
9
1
02 8C/62 Torr (lit. [23], 80–83 8C/15 Torr).
F NMR:
Under a nitrogen atmosphere, 1-chloro-4-iodo-1,1,2,2,
,3,4,4-octafluorobutane (1a) (7.25 g, 20 mmol), Na S O
2 2 4
d = ꢁ56.9 (s, 4F), ꢁ111.0 (s, 4F), ꢁ118.7 (d, J = 43.4 Hz,
4F) (lit. [23], ꢁ65.0 (t, J = 0.2 Hz, 4F), ꢁ115.0 (m, 4F),
ꢁ122.4 (m, 4F)).
3
(
13.92 g, 80 mmol) and DMSO (100 mL) was added to a
50 mL three-necked round-bottomed flask equipped with
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9
2
4g: Yellow oil. b.p. 135 8C (lit. [28], 135–136 8C). F NMR:
d = ꢁ65.0 (s, 4F), ꢁ86.2 (s, 4F) (lit. [28], ꢁ65.8 (s, 4F), ꢁ88.0
19
stirrer and condenser. The mixture was then heated to 100 8C
for 15 min. The conversion of 1a was 100%, determined
(m, 4F)).
1
9
19
by F NMR spectra [signals of F NMR at ꢁ122.2 ppm
1a: Colorless oil. b.p. 101 8C (lit. [17], 104–105 8C).
F
(4F, CF ), ꢁ130.4 ppm (4F, CF SO Na)]. After cooling,
water (100 mL), Na S O (19.04 g, 80 mmol) and iodine
NMR: d = ꢁ59.0 (s, 2F), ꢁ68.2 (s, 2F), ꢁ112.5 (s, 2F), ꢁ119.2
2
2
2
(s, 2F).
2
2 8
(
20.32 g, 80 mmol) was added to the mixture and allowed to
1b: Colorless oil. b.p. 63 8C/48 Torr (lit. [17], 68 8C/
1
9
react at room temperature for another 1 h. The resultant
solution was extracted with ether (3 ꢂ 30 mL). The
combined extracts were washed with saturated sodium
thiosulfate (3 ꢂ 30 mL), water (3 ꢂ 20 mL) and dried over
Na SO . After removing ether, the residue was distilled to
45 Torr). F NMR: d = ꢁ59.1 (s, 2F), ꢁ68.1 (t, J = 15.2 Hz,
2F), ꢁ113.1 (s, 2F), ꢁ120.2 (s, 2F), ꢁ121.0 (s, 2F), ꢁ121.2 (s,
2F).
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9
1c: White solid. F NMR: d = ꢁ59.1 (s, 2F), ꢁ68.0 (t,
J = 15.1 Hz, 2F), ꢁ113.1 (s, 2F), ꢁ120.1 (s, 2F), ꢁ120.9 (s,
2F), ꢁ121.1 (s, 2F), ꢁ121.7(s, 4F).
2
4
give 4a (4.0 g, 44%) as a red oil, b.p. 145 8C (lit. [23], 60–