3
66
T. Hudlicky et al. / Journal of Fluorine Chemistry 102 (2000) 363±367
Table 1
Preparation of ethers by bromine trifluoride
Product
Starting material
mmol)
BrF
(mmol)
3
Temperature,
8C (h)
Yield
Purity
(GC)
bp (8C)
(
1
2
3
4
5
6
7
CF
CF
CF
CF
3
3
3
3
CH
CHFOCF
CF OCF
CClFOCF
2
OCF
3
CClF
2
CH
CHClOCClF
CF OCClF (136)
CCl OCClF
FCF
CClF CF
CF CCl
2
OCF
3
(65)
70
35±45 (6)
40±45 (5)
20±30 (3)
40±50 (4)
50 (5)
8.9 g, 85%
8.6 g, 70%
22 g, 76%
9.2 g, 84%
>99.8
>99.5
99
11
� 5
3
CF
3
CF
2
CF
3
2
(66)
102
a
2
3
2
2
112
� 20
� 4
3
2
2
(50)
75
>99
b
c
CClF
CClF
2
CF
CF
2
OCHF
OCF
2
CCl
2
2
2
OCHF
OCClF
(83)
2
(150)
71
10 g, 33%
10 g, 92%
13 g, 81%
98.6
99.5
>99.5
28
2
2
3
2
2
(51)
41
30±35 (2)
30±40 (5)
10
CF
3
CF OCHF
2
2
3
2
OCHF
2
102
� 12
a
b
c
With perfluorodecalin as solvent and a catalytic amount of SbCl
5
.
Catalytic amount of SbCl
5
was added after 1 h.
After flash distillation.
1
9
Per¯uoroethylmethyl ether (3). F NMR d � 55.72 (t,
J 9.6 Hz, 2F), � 87.16 (s, 3F), � 96.06 (q, J 9.8 Hz, 2F).
-Chloro-1,2,2,2-tetra¯uoroethyl tri¯uoromethyl ether
equipped with a stir bar, a septum port, and a dry-ice
condenser was charged with bromine (5 g, 310 mmol). 2-
Chloro-1,1-di¯uoroethylene (88.1 g, 895 mmol) was con-
densed into the ¯ask. Additional bromine was added until
1
1
9
(
4). F NMR d � 55.17 (d, J 9.90 Hz, 3F), � 81.25 (q,
J 9.90 Hz, 3F), � 86.02 (S, 1F).
-Chloro-1,1,2,2-tetra¯uoroethyl di¯uoromethyl ether
5). H NMR d 6.70 (t, J 69.5 Hz, H). F NMR d
74.20 (s, 2F), � 85.10 (s, 1F), � 85.30 (t, J 4.90 Hz,
F), � 88.00 (s, 2F).
-Chloro-1,1,2,2-tetra¯uoroethyl 1,1,1-tri¯uoromethyl
the color of the bromine persisted (total Br added: 147 g,
2
2
920 mmol). The reaction mixture was washed with a solu-
tion of sodium thiosul®te to remove the excess bromine. The
organic layer was collected and distilled to give 225 g (yield
97.2%) of 1,2-dibromo-2-chloro-1,1-di¯uoroethane, purity
by GC > 98%. Distillation at room temperature gave 110 g
(yield 47.5%) of pure compound (GC > 99.5% ) and 105 g
(yield 45.4%) of less pure material (GC 95±98%). bp 100±
1
1
19
(
�
1
2
1
9
ether (6). F NMR d � 55.75 (t, J 7.3 Hz, 3F), � 74.35
S, 2F), � 89.52 (q, J 7.3 Hz, 2F).
Di¯uoromethyl 1,1,2,2,2-penta¯uoroethyl ether (7). H
(
1
1
19
1058C. H NMR d 5.9 (dd, J 8.5, 5.9 Hz, 1H). F NMR d
� 53.5 (dd, J 161.1, 7.3 Hz, 1F), � 56.9 (dd, J 161.1,
7.3 Hz, 1F).
1
19
NMR d 6.71 (t, J 69.0 Hz, H). F NMR d � 85.01 (dt,
J 68.30 Hz, J 4.8 Hz, 2F), � 86.98 (s, 3F), � 89.32 (s,
1
2
2
F).
1-Bromo-1-chloro-2,2-di¯uoroethylene, CF =CBrCl. A
2
dry 250 ml two-necked, round-bottomed ¯ask equipped
with a septum port and a distillation head was charged with
3
.2. Preparation of other ethers by other methods
,1,2-Tri¯uoroethyl methyl ether (8). A dry 100 ml two-
necked round-bottomed equipped with dry ice condenser,
4
0 g (710 mmol) of potassium hydroxide. After the reaction
1
¯ask was heated at 50±708C, 1,2-dibromo-2-chloro-1,1-
di¯uoroethane (37.5 g, 145 mmol) was added dropwise.
The crude product (23.3g, 90.5% yield, GC purity 99.4%)
was distilled as it formed. Another distillation yielded
99.8% pure (GC) product (20 g, 78% yield); the remainder
stir bar, and a septum port was charged with PdCl (0.55 g,
2
3
HSiEt (21.6 g, 186 mmol). The reaction mixture was stir-
red for 3 h at room temperature, then it was heated at 608C
for 30 min. The reaction mixture was distilled, then the
distillate was washed with water. Another distillation gave
.1 mmol), CH OCF CFHBr (30.0 g, 155 mmol), and
3 2
3
19
had a GC purity of 98%. bp 41±438C. F NMR d � 83.7 (d,
J 29.3 Hz, 1F), � 84.6 (d, J 29.3 Hz, 1F).
2-Chloro-2-bromo-1,1-di¯uoroethyl
methyl
ether,
1
less pure product (97.5%) for a total yield of 77.8%. bp
5 g of 8 (GC purity 99.8%) plus another 1.5 g of slightly
CH OCF CHBrCl (10). A dried 250 ml two-necked,
3 2
round-bottomed ¯ask, equipped with a stir bar, a septum
port, and a dry-ice condenser, was charged with sodium
methoxide (2.7 g, 50 mmol) in 50 ml methanol. 1-Bromo-1-
chloro-2,2-di¯uoroethylene (20 g, 110 mmol) was added to
the stirred reaction mixture. After 4 h, water (150 ml) was
added. The organic layer was separated and distilled to give
20.2 g (yield 85%, purity by GC > 98.5%) of the desired
product. As the product decomposed below 1008C, it was
distilled at reduced pressure (908C) to give 8.5 g (purity by
GC > 99.5%) of 10. The remainder of the product was of
1
3
3
6.58C. H NMR d 4.4 (dt, J 46.0, 8.5 Hz, 2H), 3.6 (S,
1
9
H). F NMR d � 87.9 (dt, J 14.6, 8.5 Hz, 2F), � 236.6
(
tt, J 46.4, 15.9 Hz, 1F).
2
-Bromo-1,1-di¯uoroethyl methyl ether (9) [30]. bp 278C
1
(
2
60 mm). H NMR d 3.6 (S, 3H), 3.5 (td, J 8.8, 0.7 Hz,
1
9
H). F NMR d � 79.6 (t, J 8.5 Hz, 2F).
3.3. Preparation of 2-bromo-2-chloro-1,1-difluoroethyl
methyl ether (10)
1
lesser purity (<98%). bp 112±1148C. H NMR d 5.7 (t,
19
2-Chloro-1,2-dibromo-1,1-di¯uoroethane, CBrF CHBr-
Cl. A dry 250 ml two-necked round-bottomed ¯ask
J 5.0 Hz, 1H), 3.7 (s, 3H). F NMR d � 85.2 (dd,
2
J 43.9, 4.9 Hz, 2F).