F. Leroux et al. / Journal of Fluorine Chemistry 117 (2002) 177–180
179
tion rather than fluoride addition. The resulting 1,3-octa-
diene becomes a prey of telomerization and polymerization
processes.
(21 ml, 17 g, 0.20 mol) cooled to ꢀ75 8C. When the mixture
had reached 25 8C, it was poured into a saturated aqueous
solution (0.15 l) of ammonium chloride. The organic phase
was decanted and the aqueous one extracted with diethyl
ether (3 ꢁ 50 ml). The combined organic layers were
washed with a saturated aqueous solution (2 ꢁ 50 ml) of
sodium hydrogen carbonate and dried. The product was
distilled; colorless liquid; bp 73–75 8C/15 mmHg ([15]:
4
. Experimental section
4
.1. Generalities
2
0
6
8–69 8C/10 mmHg); n 1.4380 ([15]: 1.4383); yield
D
1H and 13C NMR spectra were recorded at 400 and
01 MHz, respectively, relative to tetramethylsilane
1
18.7 g (73%). H NMR: d ¼ 5:83 (symm. m, 1 H), 5.13
(d, J ¼ 4:6, 1 H), 5.10 (s, 1 H), 3.6 (m, 1 H), 2.3 (m, 1 H), 2.2
(m, 1 H), 1.4 (m, 6 H), 0.92 (t, J ¼ 7:0, 3 H).
1
(
d ¼ 0:00 ppm) as an internal standard, all samples having
been dissolved in deuterochloroform. Coupling constants (J)
are measured in Hz and coupling patterns are abbreviated as
s (singlet), d (doublet), t (triplet), quint (quintet) and
4.3. Products
[
symm.] m ([symmetrical] multiplet).
Elementary analyses were executed by the laboratory of I.
4.3.1. 1-Bromomethyl-exo-2-fluoro-7,7-
dimethylbicyclo[2.2.1]heptane (1a)
Beetz, D-96301 Kronach. The expected numbers were
calculated on the basis of the 1999 IUPAC recommendations
regarding atomic weights (Pure Appl. Chem. 2001, 73, 667–
Finely powdered iodine (25 g, 0.10 mol) was suspended
in trichlorofluoromethane (0.50 ml) and irradiated by ultra-
sound for 30 min. exo-2-Bromo-1-bromomethyl-7,7-
dimethylbicyclo[2.2.1]heptane (exo-2,10-dibromobornane;
5.9 g, 20 mmol) was added. At ꢀ75 8C and under the action
of a vibrator-mixer, elemental fluorine, diluted in a 1:20 (v/v)
ratio by nitrogen, was introduced into the suspension
during 30 min at ꢀ75 8C. At 25 8C, the liquid phase was
decanted from unconsumed iodine and was washed with a
6
85).
Other hints concerning working routine and abbreviations
can be found in previous publications from this laboratory
e.g. in [14]).
(
4
.2. Starting materials
,10-Dibromobornane was prepared according to a
0.5 M aqueous solution (0.10 l) of sodium hydrogen sulfite
2
and brine (50 ml) before being dried and evaporated. The
residue (5.4 g) was purified by chromatography on silica gel
(0.10 l) using a 1:10 (v/v) mixture of diethyl ether and
hexanes as the eluent. The product was further purified
by sublimation: mp 56–57 8C (needles); bp 72–74 8C/
literature procedure [2]. (3-Bromopropyl)benzene, 1,4-
dibromopentane, bromocycloheptane, 1-bromoadamantane,
(
1-bromoethyl)benzene, a-bromodiphenylmethane and 2-
bromonorbornane were all purchased from commercial
suppliers.
1
0.5 mmHg; yield 2.5 g (54%). H NMR (600 MHz):
d ¼ 4:72 (ddd, J ¼ 65:5, 8.5, 4.5, 1 H), 3.71 (d, J ¼ 9:8,
1 H), 3.36 (d, J ¼ 9:6, 1 H), 2.06 (dddt, J ¼ 36:3, 14.2, 4.5,
2.3, 1 H), 1.95 (t, J ¼ 4:3, 1 H), 1.76 (dt, J ¼ 14:5, 7.6, 1 H),
1.7 (m, 1 H), 1.65 (qd, J ¼ 12:3, 23.8, 1 H), 1.32 (ddd,
J ¼ 13:5, 9.4, 4.1, 1 H), 1.03 (d, J ¼ 1:7, 3 H), 1.0 (m, 1 H),
4
.2.1. 4-Bromo-1-octene
-Octen-4-ol (see below; 21 ml, 18 g, 0.14 mol) and
1
pyridine (11 ml, 11 g, 0.14 mol) were added to phosphorus
tribromide (4.4 ml, 13 g, 47 mmol) in diethyl ether (0.10 l).
After having been heated for 3 h under reflux, the mixture
was poured on crushed ice (0.2 kg). The organic phase was
decanted and the aqueous one extracted with more diethyl
ether (2 ꢁ 50 ml). The combined organic layers were thor-
oughly washed with a saturated aqueous solution of sodium
carbonate and brine before being dried and concentrated.
Three consecutive distillations afforded a colorless liquid;
1
9
0.91 (s, 3 H). F NMR (376 MHz, relative to Cl CF):
3
d ¼ ꢀ167:0 (ddt, J ¼ 65:5, 36.3, 13.2). MS (c.i.):
þ
þ
81
þ
m=z ¼ 254 (1%, [M þ NH ], Br), 236 (2%, M ,
4
8
1
Br), 215 (11%), 172 (14%), 155 (25%), 135 (100%).
C H BrF (235.14): calcd. C 51.08, H 6.86; found C
51.14, H 6.83%.
1
0 16
When exo-2,10-dibromobornane was treated with a five-
fold excess of N-iodosuccinimide and triethylamine tris(hy-
drogen fluoride) as described below (see the preparation of
2-fluoronorbornane) rather than with iodine fluoride, the
yield amounted to only 34%.
2
0
1
bp 65–66 8C/15 mmHg; nD 1.4629; yield 15.0 g (56%). H
NMR: d ¼ 5:87 (symm. m, 1 H), 5.17 (t, J ¼ 1:2, 1 H), 5.1
(
1
m, 1 H), 4.05 (quint, J ¼ 6:5, 1 H), 2.63 (t, J ¼ 6:5, 2 H),
8 15
.9 (m, 2 H), 1.4 (m, 4 H), 0.94 (t, J ¼ 7:3, 3 H). C H Br
(
191.11): calcd. C 50.28, H 7.91; found 50.69, H 8.20.
4.3.2. 1-Bromomethyl-exo-2-chloro-7,7-
dimethylbicyclo[2.2.1]heptane (1b)
Iodine chloride (iodonium chloride; 18 g, 0.11 mol) was
dissolved in ice-cold dichloromethane (0.20 l) containing
exo-2-bromo-1-bromomethyl-7,7-dimethylbicyclo[2.2.1]-
heptane (30 g, 0.10 mol). After 1 h at 0 8C, the mixture was
4
.2.2. 1-Octen-4-ol
Allyl bromide (17 ml, 24 g, 0.20 mol) was added to a
vigorously stirred suspension of magnesium turnings (4.9 g,
.20 mol) in diethyl ether (0.40 l) during 30 min, before
being added dropwise in the course of 30 min, to pentanal
0