Full Paper
43.9 mmol, 1.10 equiv.) was added dropwise and the solution was
stirred for 2 h at room temperature. Subsequently, pyridine
4-Cyclopropylbutanal: 4-Cyclopropylbutan-1-ol 23 (5.79 g,
44.5 mmol, 1.00 equiv.) in CH2Cl2 (400 mL) was cooled to 0 °C.
(4.30 mL, 53.3 mmol, 1.10 equiv.) was added dropwise to the reac- Dess–Martin periodinane (20.7 g, 49.0 mmol, 1.10 equiv.) was added
tion solution and the mixture was cooled to 0 °C. 5-Hexen-1-ol
(4.80 mL, 39.9 mmol, 1.00 equiv.) in CH2Cl2 (7 mL) was added drop-
in one portion and stirred for 1 h. The reaction was then stirred for
a further hour at room temperature. The reaction was diluted with
wise and the solution was stirred for 20 h at room temperature. cooled pentane (200 mL) and the solid was removed through a
After complete conversion of the alcohol, which was controlled via
TLC (hexane/ethyl acetate, 90:10), pentane (20 mL) was added to
the reaction solution. The reaction flask was cooled to –78 °C and
the precipitate was filtered off. The clear reaction solution was con-
Celite pad. The product was concentrated via distillation (60 °C) and
a yellow liquid was obtained. 1H NMR (300 MHz, CDCl3): δ = 9.77
(t, J = 1.86, 1 H, HC=O), 2.46 (td, J = 7.36, 1.86, 1 H, CH2HC=O), 1.74
(p, J = 7.36, 2 H, CH2CH2HC=O), 1.24 (m, 2 H, CH2CH2CH2HC=O),
centrated and washed with hydrochloric acid (1 M, 3 × 20 mL). The 0.64 (m, 1 H, CHCH2CH2), 0.42 (m, 2 H, CHCH2CH2), 0.01 (m, 2 H,
aqueous phase was extracted with pentane (3 × 20 mL). The com-
bined organic phases were washed with saturated NaHCO3 (10 mL)
and dried with Na2SO4. The solution was again concentrated and
distilled at reduced pressure (61–63 °C, 45 mbar). A clear oil was
CHCH2CH2) ppm.[28]
1-(Penten-4-yl)cyclopropane (20): Methyltriphenylphosphonium
bromide (24 g, 67 mmol, 1.5 equiv.) in Et2O (220 mL) was cooled to
0 °C and n-butyllithium (2.5
M, 27 mL, 67 mmol, 1.5 equiv.) was
1
obtained (3.17 g, 19.4 mmol, 49 %). H NMR (300 MHz, CDCl3): δ =
added. The yellow suspension was stirred for 1 h. 4-Cyclopropyl-
butanal (5.8 g, 44 mmol, 1.0 equiv.) in Et2O (45 mL) was added at
10 °C. The suspension was stirred for 1 h at room temperature and
quenched with saturated NH4Cl (150 mL). The suspension was fil-
tered through a Celite pad and concentrated via distillation. The
crude product was purified by column chromatography (silica gel,
eluent: pentane) and concentrated via distillation (oil bath = 150 °C)
to get a clear liquid. Finally, it was stirred over NaH and condensed
under reduced pressure (0.52 g, 4.7 mmol, 10 %). 1-(Penten-4-yl)-
5.88–5.72 (ddt, J = 16.9, 10.2, 6.7 Hz, 1 H, CH2CH), 5.08–4.94 (m, 2
H, CH2CH), 3.46–3.37 (t, J = 6.8 Hz, 2 H, CH2Br), 2.15–2.03 (m, 2
H, CH2CHCH2), 1.94–1.82 (m, 2 H, CH2CH2Br), 1.61–1.48 (m, 2 H,
CH2CH2CH2Br) ppm.[25]
6-(tert-Butyldimethylsilyloxy)-1-hexene: TBDMSCl (24.5 g,
162 mmol, 1.01 equiv.) and imidazole (13.1 g, 193 mmol, 1.20 equiv.)
were added to a solution of 5-hexen-1-ol (16.0 g, 160 mmol,
1.00 equiv.) in THF (80 mL). After stirring overnight desalinated wa-
ter (40 mL) was added. The aqueous layer was extracted with di-
ethyl ether (5 × 20 mL) and dried with Na2SO4. After evaporation
of diethyl ether, the crude product was distilled under reduced
pressure to obtain the desired product (99 °C, 30 mbar). (29.8 g,
139 mmol, 87 %). 1H NMR (300 MHz, CDCl3): δ = 5.90–5.73 (ddt, J =
16.9, 10.2, 6.7 Hz, 1 H, CH2=CH), 5.06–4.90 (m, 2 H, CH2=CH), 3.67–
3.57 (t, J = 6.3 Hz, 2 H, CH2OTBDMS), 2.14–1.99 (d, J = 7.1 Hz, 2 H,
CH2CH2OTBDMS), 1.63–1.48 (m, 2 H, CH2CH2CH2OTBDMS), 1.48–1.37
(m, 2 H, CH2CH2CH2CH2OTBDMS), 0.95–0.84 [s, 9 H, OSi(CH2)2(CH3)3],
1
cyclopropane 20 is very volatile and has to be stored at –20 °C. H
NMR (300 MHz, CDCl3): δ = 5.82 (ddt, J = 16.9, 10.1, 6.6 Hz, 1 H,
CH2=CH); 4.97 (m, 2 H, CH2=CH), 2.08 (m, 2 H, CH2=CHCH2), 1.51
(m, 2 H, CH2=CHCH2CH2), 1.21 (m, 2 H, CH2=CHCH2CH2CH2), 0.66
(m, 1 H, CHCH2CH2), 0.40 (m, 2 H, CHCH2CH2), 0.01 (m, 2 H,
CHCH2CH2) ppm. 13C{1H} NMR (75 MHz, CDCl3): δ = 139.3, 114.3,
34.4, 33.8, 29.1, 10.9, 4.52 ppm.
10-Bromo-1,1,1,2,2,3,3,4,4-nonafluoro-6-iododecane (23): tBu3P
(0.0153 g, 0.0756 mmol, 10 mol-%) and B(C6F5)3 (0.0386 g,
0.0756 mmol, 10 mol-%) were weighed in an amber glass screw-
top jar and dissolved in CH2Cl2 (2.1 mL). After addition of 6-bromo-
hexene (18) (0.100 mL, 0.748 mmol, 1.00 equiv.) and nonafluoro-1-
iodobutane (1) (0.130 mL, 0.755 mmol, 1.01 equiv.) the jar was
sealed with a Teflon-insert screw cap and the solution was stirred
for 68 h. After removal of the solvent the crude product was puri-
fied by column chromatography (silica gel, eluent: pentane, Rf =
0.73) to give product 23 (0.352 g, 0.692 mmol, 93 %). 1H NMR
(300 MHz, CDCl3): δ = 4.40–4.25 (m, 1 H, CHI), 3.51–3.36 (t, J =
6.6 Hz, 2 H, CH2Br), 3.07–2.64 (m, 2 H, CH2CF2), 2.08–1.46 (m, 6 H,
CHI-CH2CH2CH2-CH2Br) ppm. 13C{1H} NMR (75 MHz, CDCl3): δ = 42.0,
41.7, 41.4, 39.5, 33.1, 31.7, 28.5, 19.9 ppm. 19F NMR (282 MHz,
CDCl3): δ = –80.9 to –81.1 (t, J = 9.6 Hz, 3F, CF3), –111.1to –115.5
(m, 2 F, CF2), –124.3 to –124.8 (m, 2 F, CF2), –125.6to –126.2 (m, 2 F,
0.09–0.01 [s, 6 H, OSi(CH ) (CH ) ] ppm. IR (film on NaCl): ν =
˜
2 2
3 3
3077, 2930, 1642, 1472, 1387, 1361, 1255, 1102, 910, 835, 775, 661
cm–1 [26]
tert-Butyl(4-cyclopropylbutoxy)dimethylsilane: Et2Zn (1.0
.
M
in
hexane, 140 mL, 140 mmol, 2.00 equiv.) in CH2Cl2 (250 mL) was
cooled to 0 °C and trifluoroacetic acid (11.0 mL, 142 mmol,
2.04 equiv.) in CH2Cl2 (250 mL) was added over 2 h. After stirring
the solution for 30 min a solution of freshly distilled diiodomethane
(11.3 mL, 140 mmol, 2.00 equiv.) in CH2Cl2 (250 mL) was added over
1 h. After stirring for another 30 min 6-(tert-butyldimethylsilyloxy)-
1-hexene (14.9 g, 69.7 mmol) in CH2Cl2 (140 mL) was added. The
reaction was stirred at room temperature until the alkene signals
1
disappeared completely in the H NMR spectra. A saturated NH4Cl
solution (200 mL) was added and the aqueous layer was extracted
with diethyl ether (5 × 20 mL) and dried with Na2SO4. The solution
was concentrated (60 mL) and used as crude product.
CF ). IR (film on NaCl): ν = 3215, 2942, 1455, 1433, 1350, 1232, 1134,
˜
2
880, 724 cm–1. C10H11BrF9I: calcd. C 23.60, H 2.18; found C 23.61, H
2.42.
4-Cyclopropylbutane-1-ol: The crude product tert-butyl(4-cyclo-
propylbutoxy)dimethylsilane was added to tetra-n-butylammonium
fluoride-trihydrate (49.1 g, 138 mmol, 1.99 equiv.) and stirred over-
night. After completion, saturated NH4Cl (150 mL) was added to the
reaction and the organic phase was extracted with diethyl ether
(3 × 100 mL). The combined organic phases where washed with
brine (200 mL) and dried with Na2SO4. After evaporation (750 mbar,
40 °C) of the solvent the yellow liquid was purified by column chro-
matography (silica gel, pentane/diethyl ether = 3:1) to give the de-
sired product as light yellow liquid (5.79 g, 44.5 mmol, 63 %).
1H NMR (300 MHz, CDCl3): 3.63 (t, J = 6.8, 2 H, CH2OH), 1.60 (m, 2
H, CH2CH2OH), 1.46 (m, 2 H, CH2CH2CH2OH), 1.23 (m, 2 H,
CH2CH2CH2CH2OH), 0.65 (m, 1 H, CHCH2CH2); 0.39 (m, 2 H,
CHCH2CH2), 0.00 (m, 2 H, CHCH2CH2) ppm.[27]
Acknowledgments
The generous support of M. Spittler by a fellowship of the Studi-
enstiftung des deutschen Volkes is most gratefully acknowl-
edged.
Keywords: Frustrated Lewis pairs · Perfluoroalkylation ·
Reaction mechanisms · Halogenation · Radicals
[1] P. Kirsch, Modern Fluoroorganic Chemistry: Synthesis, Reactivity, Applica-
tions, 2nd ed., Wiley-VCH, Weinheim, 2013.
Eur. J. Org. Chem. 0000, 0–0
10
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim