Synthesis of lactones with a chlorodifluoromethyl group

Article abstract of DOI:10.1016/j.jfluchem.2004.11.005

Synthetic routes to lactones with a chlorodifluoromethyl group via S _N2′, oxidation and lactonization reactions, were described.

Full text of DOI:10.1016/j.jfluchem.2004.11.005

Journal of Fluorine Chemistry 126 (2005) 135–139
www.elsevier.com/locate/fluor
Synthesis of lactones with a chlorodifluoromethyl group
*
Mitsuo Kimura, Tsuneyoshi Tominaga, Tomoya Kitazume
Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta,
Midori-ku Yokohama 226-8501, Japan
Received 29 September 2004; received in revised form 27 October 2004; accepted 2 November 2004
Available online 18 December 2004
Abstract
Synthetic routes to lactones with a chlorodifluoromethyl group via SN20, oxidation and lactonization reactions, were described.
# 2004 Elsevier B.V. All rights reserved.
Keywords: Chlorodifluoromethylation; Lactonization; Lactone
1. Introduction
The challenge in fluorine chemistry to develop new
products, practical processes, reaction media, conditions
and/or utility of materials is one of the most important issues
[1–6]. Especially, introduction of fluorine(s) and/or a
fluoromethyl group into organic materials has been one of
the major strategies in various fields such as pharmacology
or functionalized materials because of its unique biological
2. Results and discussion
and physical properties [7,8]. Recently, we have reported the
convenient construction of type B molecules by the SN20
reaction of the corresponding allylic derivatives A [9].
Accordingly, we have devoted our attention to open a new
road to the functionalized building blocks with a fluor-
omethyl moiety for attaining ready access to these types of
molecules by the application of type B molecules. In this
paper, we would like to describe the synthetic routes to
lactones with a chlorodifluoromethyl group from the type B
molecules. As a continuation of our interest in the synthesis
of materials modified with a fluoromethyl group, which
often exhibit unique biological properties [2], we examined
the synthesis of lactones with a chlorodifluoromethyl group
from the type B molecules via the SN20 reaction.
Synthesis of chlorodifluoromethylated lactones was
designed by the following synthetic route shown in Scheme
1. The synthetic route to compound 5 from chlorodifluor-
oacetate (1) is the general synthetic ways in the organic
synthesis. The SN20 reactions using Grignard reagents were
examined based on the previously employed conditions [10]
for the construction of CF3-containing tertiary carbon
centers, giving the desired SN20 compound 6 from
compound 5. When the reaction was attempted in the
presence of Lewis acid such as TBSCl, it was found to play a
significantly important role in accelerating the reaction, and
compound 6 was obtained in high yield. Further, oxidation
of carbon–carbon double bond by O3 gave the corresponding
compound 7. After protecting the OH group with TBSOTf,
compound 9 was obtained via the oxidation reaction. To
obtain the target material 10, we examined the lactonization
of the compound 9 with the fluoride anion generated from
TBAF in THF.
* Corresponding author. Tel.: +81 45 924 5754; fax: +81 45 924 5780.
E-mail address: tkitazum@bio.titech.ac.jp (T. Kitazume).
0022-1139/$ – see front matter # 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.jfluchem.2004.11.005

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M. Kimura et al. / Journal of Fluorine Chemistry 126 (2005) 135–139
Scheme 1. (a) PhCH2CH2MgBr, Et2O; (b) Ph3P = CHC(O)CH3, THF, Et3N; (c) NaBH4, MeOH; (d) Ac2O, dimethylaminopyridine (DAMP), Et3N, CH2Cl2; (e)
RMgBr, CuCN, TMSCl, Et2O, 0 8C; (f) O3, MeOH; (g) NaBH4; (h) TBSOTf, Et3N, DAMP, CH2Cl2; (i) RuCl3ꢁH2O, NaIO4, CH3CN–CCl4–H2O; (j) TBAF,
THF.
(10 ml), phenetyl bromide (13.5 ml, 100 mmol) in
diethyl ether (0.90 ml) was added slowly at room
The structure of compound 10a (R = i-Pr) was confirmed
1
by H, 19F and 13C NMR spectra and coupling constants
temperature under an atmosphere of argon, and then the
whole was stirred for 1 h at that temperature. Into the
(JH-H and JH-F). In the case of compound 10a, the coupling
pattern of fluorine supports the interaction of protons
mixture,
methyl
chlorodifluoroacetate
(11 ml,
with the group, and the coupling patterns of protons
support the interaction of proton with group. 13C NMR
spectra have eight signals containing CF2 carbon atom
133.48 (d ppm, triplet, J = 299.7 Hz), CF2–C carbon atom
49.81 (d ppm, triplet, J = 17.8 Hz), and carbonyl carbon
101 mmol) was added at ꢀ78 8C under an atmosphere
of argon, and then the whole was stirred for 1 h at
ꢀ78 8C. The mixture was quenched with 3N HCl and
saturated NH4Cl, and then extracted with diethyl ether.
After drying with MgSO4, the product was distilled
under pressure giving chlorodifluoromethylphenetyl
ketone (2) in 58%.
1
atom 171.94 (d ppm). From the results of H, 19F and 13C
NMR spectra, we have determined the structure of obtained
material.
1H NMR (CDCl3): d 2.97–3.03 (2 H, m), 3.06–3.12 (2 H,
m), 7.19–7.34 (5 H, Ar–H). 13C NMR (CDC13): d 28.85,
36.86, 119.59 (t, J = 305 Hz), 126.52, 128.15, 128.56, 13-
9.19, 190.71 (t, J = 29.5 Hz). 19F NMR (CDCl3): d 93.4 ppm
from int. C6F6.
3. Experimental
3.1. General
All commercially available reagents were used without
1
(b) 1-Chloro-1,1-difluoro-2-phenetyl-2-penten-4-one (3).
Into the mixture solution of acetonyltriphenylpho-
sphonium chloride (17.1 g, 48 mmol) in THF (50 ml),
triethylamine (8.1 ml, 60 mmol) was added slowly at
0 8C under an atmosphere of argon, and then the whole
was stirred for 30 min at that temperature. The mixture
solution of chlorodifluoromethylphenetyl ketone (2)
(8.75 g, 40 mmol) in THF (20 ml) was added into the
above solution, and then the whole was refluxed for 3 h.
The mixture was poured into hexane, and then the
precipitates were filtered. After removing the solvent
further purification. Chemical shifts of H (300 MHz) and
13C NMR (75 MHz) spectra were recorded in ppm (d)
downfield from the following internal standard (Me4Si, d
0.00) in CDCl3. The 19F (282 MHz) NMR spectra were
recorded in ppm downfield from internal standard C6F6 in
CDCl3 using a VXR 300 instrument.
3.2. 1-Chloro-1,1-difluoro-2-phenetyl-2-penten-4-one (3)
(a) Chlorodifluoromethylphenetyl ketone (2). Into the
mixture of Mg (2.71 g, 119 mmol) and diethyl ether

M. Kimura et al. / Journal of Fluorine Chemistry 126 (2005) 135–139
137
under vacuum, the product was purified by column
chromatography on silica gel using a mixture of hexane-
ethyl acetate, giving 1-chloro-l,1-difluoro-2-phenetyl-2-
penten-4-one (3) in 86% yield (8.88 g).
128.35, 128.35, 131.45 (t, J = 7.4 Hz), 135.61 (t, J = 22.-
0 Hz), 140.46, 169.72. 19F NMR(CDCl3): d 108.6 (1 F, d,
J = 160.3 Hz), 109.49 (1 F, d, J = 160.3 Hz). IR (neat): n
1739, 1604 cmꢀ1. Anal. Calcd for C15H17C1F202, 59.51;
H, 5.66. Found: C, 59.15; H, 5.62.
1H NMR (CDCl3): d 2.27 (3 H, s), 2.80–2.93 (4 H, m),
6.61 (1 H, t, J = 1.4 Hz), 7.18–7.32 (5 H, Ar–H). 13C NMR
(CDCl3): d 29.91 (t, J = 1.2 Hz), 32.10, 35.21, 125.03 (t,
J = 6.7 Hz), 126.04, 126.20 (t, J = 292.0Hz), 128.26, 128-
.37, 140.67, 147.43 (t, J = 22.3 Hz), 197.42. 19F NMR
(CDCl3): d 105.24 (d, J = 1.3 Hz). IR (neat): n 1701, 1631,
1604 cmꢀ1. Anal. Calcd for C13H15C1F20, 60.36; H, 5.07.
Found: C, 60.19; H, 5.33.
3.4. 4-Chlorodifluoromethyl-4-isopropyl-6-phenyl-2-
hexene (6a)
Into the mixture solution of acetate derivative of 1-
chloro-1,1-difluoro-2-phenetyl-2-penten-4-ol (5) (2.99 g,
9.88 mmol), TNSCl (1.30 ml, 10.2 mmol), CuCN
(180 mg, 2.01 mmol) in diethyl ether (20 ml), i-PrMgCl
(15 mmol: 2 M in Et2O) was added at 0 8C under an argon
atmosphere. After quenching with water, 10% NH3 aq. and
sat. NH4Cl aq. were added. Oily materials were extracted
with diethyl ether, and dried over anhydrous MgSO4, and
washed with brine. After removal of the solvent, the product
(6a) was purified by column chromatography on silica gel in
81% yield.
1H NMR (CDCl3): d 0.98 (3 H, d, J = 7.4 Hz), 1.00 (3 H,
d, J = 7.2 Hz), 1.79 (3 H, dd, J = 1.4, 6.3 Hz), 1.88–2.07 (2
H, m), 2.25 (1 H, sep, J = 6.9 Hz), 2.58–2.78 (2 H, m), 5.51
(1 H, dq, J = 15.9, 1.4 Hz), 5.68 (1 H, dq, J= 15.9, 6.3 Hz),
7.19–7.33 (5 H, Ar–H). 13C NMR (CDCl3): d 18.35, 18.73,
18.76, 30.46, 31.30, 33.95, 55.57 (t, J = 17.8 Hz), 125.86,
127.35 (t, J = 3.7 Hz), 128.19, 128.40, 134.79 (t,
J = 302.3 Hz), 137.90 (t, J = 7.2 Hz), 142.53. 19F NMR
(CDCl3): d 112.9 (1 F, d, J = 162 Hz), 113.8 (1 F, d) ppm
from int. C6F6.
3.3. Acetate derivative of 1-chloro-1,1-difluoro-2-phenetyl-
2-penten-4-ol (5)
(a) 1-Chloro-1,1-difluoro-2-phenetyl-2-penten-4-ol
(4).
The mixture of 1-chloro-1,1-difluoro-2-phenetyl-2-pen-
ten-4-one (3) (6.16 g, 23.8 mmol) and NaBH4 (2.34 g,
72.4 mmol) in MeOH (30 ml) was stirred for 2 h at room
temperature. The mixture was quenched with 3N HCl,
and oily materials were extracted with diethyl ether,
and washed with brine. The organic layer was dried
over anhydrous MgSO4 and the solvent was removed.
1-Chloro-1,1-difluoro-2-phenetyl-2-penten-4-ol (4) (89%
yield, 5.54 g) was purified by column chromatography
on silica gel.
1N NMR (CDCl3): d 1.11 (3 H, d, J = 6.3 Hz), 2.59–2.65
(2 H, m), 2.86 (2 H, t, J = 7.6 Hz), 4.14–4.25 (1 H, m), 5.99
(1 H, td, J = 1.4, 9.2 Hz), 7.20–7.36 (5 H, Ar–H). 13C NMR
(CDCl3): d 22.354, 28.493 (t, J = 0.9 Hz), 35.09, 63.72, 1-
26.29, 127.17 (t, J = 291.0 Hz), 128.34, 128.62, 132.99 (t,
J = 21.8 Hz), 136.01 (t, J = 7.0 Hz), 140.43. 19F NMR(C-
DCl3): d 109.20 (1 F, d, J = 159.8 Hz), 110.33 (1 F, d,
J = 160.3 Hz). IR (neat): n 3329 (OH) cmꢀ1. Anal. Calcd
for: C, 59.89; H, 5.80. Found: C, 59.52; H, 6.08.
3.5. 4-Chlorodifluoromethyl-4-ethyl-6-phenyl-2-hexene
(6b)
1H NMR (CDCl3): d 0.96 (3 H, tt, J = 1.4, 7.6 Hz), 1.68–
2.10 (4 H, m), 1.78 (3 H, dd, J = 1.6, 6.6 Hz), 2.51–2.68 (2
H, m), 5.42 (1 H, qd, J = 1.7, 15.8 Hz), 5.69 (1 H, qd, J = 6.4,
15.9 Hz), 7.18–7.33 (5 H, Ar–H). 13C NMR (CDCl3): d 8.29
(t, J = 1.6 Hz), 18.49, 24.77 (t, J = 2.1 Hz), 30.21 (t,
J = 1.9 Hz), 33.97 (t, J = 1.6 Hz), 53.00 (t, J = l8.6 Hz),
125.78, 128.07, 128.28, 128.60, 129.54, 134.29 (t,
J = 300 Hz), 142.05 (t, J = 0.7 Hz). 19F NMR (CDCl3): d
106.9 ppm from int. C6F6. IR (neat): n 1604 cmꢀ1. Anal.
Calcd for C15H19ClF2: C, 66.05; H, 7.02. Found C, 65.81; H,
7.45.
(b) The mixture of 1-chloro-1,1-difluoro-2-phenetyl-2-
penten-4-ol (4) (4.49 g, 17.2 mmol), dimethylamino-
pyridine (DAMP, 222 mg, 1.82 mmol), triethylamine
(2.9 ml, 20.9 mmol) and Ac2O (1.90 ml, 20.2 mmol) in
dichloromethane (25 ml) was stirred at room tempera-
ture under an atmosphere of argon. After stirring of 2 h
at room temperature, the mixture was quenched with 3N
HCl, and oily materials were extracted with diethyl ether
and washed with brine. After drying over anhydrous
MgSO4, the solvent was removed. Acetate 5 (87% yield)
was purified by column chromatgraphy on silica gel.
3.6. 2-Chlorodifluoromethyl-2-isopropyl-4-phenylbutan-1-
ol (7a)
Into the mixture solution of 4-chlorodifluoromethyl-4-
isopropyl-6-phenyl-2-hexene (6a) (4.02 g, 14 mmol) in
MeOH (25 ml) at ꢀ78 8C, O3 was bubbled for 2 h and
then argon was bubbled into the mixture for a few minutes.
The reaction temperature was warmed to 0 8C, and then
NaBH4 (444 mg, 11.7 mmol) was added to the mixture
solution. After 6 h of stirring at 0 8C, the mixture was
1H NMR (CDCl3): d 1.13 (3 H, d, J = 6.3 Hz), 2.03 (3 H,
s), 2.52–2.96 (4 H, m), 5.45 (1 H, qd, J = 6.4, 9.6 Hz), 5.97
(1 H, td, J = 1.5, 9.3 Hz), 7.18–7.33 (5 H, Ar–H). 13C N-
MR(CDCl3): d 19.86 (t, J = 1.0 Hz), 21.08, 28.89 (t, J =
0.9 Hz), 35.15, 66.17, 126.12, 126.913 (t, J = 291.0 Hz),

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M. Kimura et al. / Journal of Fluorine Chemistry 126 (2005) 135–139
(351 mg, 0.90 mmol) and NaIO4 (3.78 g, 17.7 mmol) in
CCl4 (2 ml), CH3CN (2 ml) and H2O (3 ml) was stirred
for 1 h at room temperature. Into the above mixture,
RuCl3ꢁH2O (7 mg, 0.034 mmol) was added, and the
whole was stirred for 3 days at room temperature.
Oily materials were extracted with diethyl ether, and the
ethereal layer was washed with brine. After drying over
anhydrous MgSO4, the solvent was removed. 5-tert-
Butyldimethylsiloxy-4-chlorodifluoromethyl-4-isopropyl
pentanoic acid (9a) was purified by column chromato-
graphy on silica gel in 58% yield.
quenched with 3N HCl. Oily materials were extracted with
diethyl ether, and the ethereal solution was washed with
brine, and dried over anhydrous MgSO4. After removal of
the solvent, 2-chloro-difluoromethyl-2-isopropyl-4-phenyl-
butan-l-ol (7a) (67% yield) was purified by column
chromatography on silica gel.
1H NMR (CDCl3): d 1.08 (3 H, d, J = 6.9 Hz), 1.11 (3 H,
d, J = 6.3 Hz), 1.83–2.02 (2 H, m), 2.35 (1 H, sep,
J = 6.9 Hz), 2.60–2.79 (2 H, m), 3.91 (2 H, s), 7.18–7.33
(5 H, Ar–H). 13C NMR (CDCl3): d 18.24, 18.44, 29.62,
30.05, 32.35, 54.00 (t, J = 16.3 Hz), 63.63 (t, J = 3.7 Hz),
125.86, 128.13, 128.37, 134.73 (t, J = 302.6 Hz), 141.95.
19F NMR (CDCl3): d 114.8 ppm from int. C6F6.
1H NMR (CDCl3): d 0.07 (6 H, s), 0.89 (9 H, s), 1.04 (3 H,
d, J = 7.1 Hz), 1.05 (3 H, d, J = 6.9 Hz), 1.90–2.10 (2 H, m),
2.24 (1 H, sep, J = 7.1 Hz), 2.40–2.61 (2 H, m), 3.72 (1 H, d,
J = 10.7 Hz), 3.80 (1 H, d, J = 10.7 Hz). 13C NMR (CDCl3):
d ꢀ5.72, ꢀ5.67, 18.15, 18.40, 18.51, 25.05, 25.70, 29.11,
30.08, 53.53 (t, J = 16.6 Hz), 62.98 (t, J = 4.0 Hz), 134.26
(t, J = 301.7 Hz), 179.75. 19F NMR (CDCl3): d 114.0 ppm
from int. C6F6.
3.7. 2-Chlorodifluoromethyl-2-ethyl-4-phenylbutan-l-ol
(7b)
1H NMR (CDCl3): d 1.03 (3 H, tt, J = 1.2, 7.6 Hz), 1.77 (2
H, J = 7.5 Hz), 1.86–1.92 (2 H, m), 2.59–2.76 (2 H, m), 3.79
(2 H, s), 7.17–7.33 (5 H, Ar–H). 13C NMR (CDCl3): d 8.08
(t, J = 1.6 Hz), 22.91 (t, J = 2.3 Hz), 29.86 (t, J = 1.9 Hz),
32.33 (t, J = 1.9 Hz), 52.14 (t, J = 16.9 Hz), 64.14 (t,
J = 2.7 Hz), 125.86, 128.06, 128.30, 134.87 (t, J = 300 Hz),
141.73. 19F NMR (CDCl3): d 109.5 (1 F, d, J = 168.3 Hz),
110.0 (1 F, d) ppm from int. C6F6. IR (neat): n 3406,
1600 cmꢀ1. Anal. Calcd for C13H17ClF2O: C, 59.43; H,
6.52. Found C, 59.72; H, 6.70.
3.9. 5-tert-Butyldimethylsiloxy-4-chlorodifluoromethyl-4-
ethyl pentanoic acid (9b)
(a) 1-tert-Butyldimethylsiloxy-2-chlorodifluoromethyl-2-
ethyl-4-phenylbutane (8b): 1H NMR (CDCl3): d 0.08 (3
H, s), 0.91 (9 H, s), 0.98 (3 H, tt, J = 1.5, 7.6 Hz), 1.74 (1
H, q, J = 7.42 Hz), 1.75 (1 H, q, J = 7.7 Hz), 1.81–1.97
(2 H, m), 2.58–2.75 (2 H, m), 3.71 (1 H, d, J = 10.4 Hz),
3.76 (1 H, d, J = 10.4 Hz), 7.16–7.32 (5 H, Ar–H). 13C
NMR (CDCl3): d ꢀ5.57, 8.43 (t, J = 1.9 Hz), 18.23,
24.20 (t, J = 1.9 Hz), 25.85, 30.30 (t, J = 1.9 Hz), 33.38
(t, J = 2.0 Hz), 52.36 (t, J = 17.0 Hz), 63.59 (t,
J = 3.3 Hz), 125.82, 128.20, 128.36, 134.73 (t,
J = 301 Hz), 142.34. 19F NMR (CDCl3): d 110.3 ppm
from int. C6F6. IR (neat): n 3062, 1604 cmꢀ1. Anal.
Calcd for C19H31ClF2OSi: C, 60.53; H, 8.29. Found C,
60.51; H, 8.59.
3.8. 5-tert-Butyldimethylsiloxy-4-chlorodifluoromethyl-4-
isopropyl pentanoic acid (9a)
(a) 1-tert-Butyldimethylsiloxy-2-chlorodifluoromethyl-2-
isopropyl-4-phenylbutane (8a). Into the mixture, solution
of 2-chlorodifluoromethyl-2-isopropyl-4-phenylbutan-
1-ol (7a) (750 mg, 2.71 mmol), dimethylaminopyridine
(DAMP, 35 mg, 0.29 mmol) in CH2Cl2 (8 ml), triethy-
lamine (0.5 ml, 3.6 mmol) and TBSOTf (0.8 ml,
3.5 mmol) was added at 0 8C. After stirring of 27 h at
room temperature, the mixture was poured into diethyl
ether, and the whole was washed with brine. The
ethereal layer was dried over anhydrous MgSO4, and
then the solvent was removed. The target material (8a)
was obtained by column chromatography on silica gel in
55% yield.
(b) 5-tert-Butyldimethylsiloxy-4-chlorodifluoromethyl-4-
1
ethyl pentanoic acid (9b): H NMR (CDCl3): d 0.06 (3
H, s), 0.89 (9 H, s), 0.96 (3 H, tt, J = 1.5, 7.6 Hz), 1.54–
1.78 (2 H, m), 1.89–2.05 (2 H, m), 2.34–2.59 (2 H, m),
3.65 (1 H, d, J = 10.4 Hz), 3.70 (1 H, d, J = 10.4 Hz).
13C NMR (CDCl3): d ꢀ5.76, 8.19 (t, J = 1.7 Hz), 18.06,
24.03 (t, J = 2.0 Hz), 25.66, 28.88 (t, J = 1.9 Hz), 51.57
(t, J = 17.3 Hz), 63.32 (t, J = 3.3 Hz), 134.15
(300.5 Hz), 179.65. 19F NMR (CDCl3): d 109.6 ppm
from int, C6F6. IR (neat): n 1716 (C=O) cmꢀ1. Anal.
Calcd for C14H27ClF2O3Si: C, 48.75; H, 7.89. Found C,
49.63; H, 7.86.
1N NMR (CDCl3): d 0.08 (6 H, s), 0.91 (9 H, s), 1.06 (3 H,
d, J = 7.1 Hz), 1.07 (3 H, d, J = 6.9 Hz), 1.79–2.03 (2 H, m),
2.34 (1 H, sep, J = 7.1 Hz), 2.58–2.79 (2 H, m), 3.79 (1 H, d,
J = 10.7 Hz), 3.88 (1 H, d, J = 10.7 Hz), 7.18–7.32 (5 H, Ar–
H). 13C NMR (CDCl3): d ꢀ5.58, ꢀ5.56, 18.24, 18.56, 18.59,
25.89, 30.01, 30.43, 32.91, 54.27 (t, J = 16.6 Hz), 63.29 (t,
J = 4.0 Hz), 125.86, 128.20, 128.39, 134.7l (t, J = 30l.3 Hz),
142.44. 19F NMR (CDCl3): d 114.8 ppm from int. C6F6.
3.10. 5-Chlorodifluoromethyl-5-isopropyltetrahydropyran-
2-one (10a)
(b) The mixture solution of 1-tert-butyldimethylsiloxy-2-
chlorodifluoromethyl-2-isopropyl-4-phenylbutane (8a)
A mixture solution of 5-tert-butyldimethylsiloxy-4-
chlorodifluoromethyl-4-isopropyl pentanoic acid (9a)

M. Kimura et al. / Journal of Fluorine Chemistry 126 (2005) 135–139
139
(192 mg) and tetra-n-butylammonium fluoride (TBAF, 1 M
in THF, 3 ml) in THF (4 ml) was stirred for 2 days at room
temperature under an argon atmosphere, and then the whole
was diluted with diethyl ether. The whole was washed
with sat. NH4C1 aq. and brine. Oily materials were extracted
with diethyl ether, and the ethereal layer was dried
over anhydrous MgSO4. After removal of the solvent,
5-chlorodifluoromethyl-5-isopropyltetrahydropyran-2-one
(10a) was obtained by column chromatography on silica gel
in 67% yield. 1H NMR (CDCl3): d 1.06 (3 H, d, J = 6.6 Hz),
1.08 (3 H, d, J = 6.6 Hz), 1.85–1.95 (1 H, m), 2.09–2.27 (2
H, m), 2.47–2.69 (2 H, m), 4.27 (1 H, d, J = 12.6 Hz), 4.41 (1
H, d, J = 12.6 Hz). 13C NMR (CDCl3): d 18.11, 23.16 (t,
J = 2.3 Hz), 28.30, 33.37, 49.81 (t, J = 17.8 Hz), 67.38 (t,
J = 3.4 Hz), 133.48 (t, J = 299.7 Hz), 171.94. 19F NMR
(CDCl3): d 106.6 (1 F, d, J = 169.8 Hz), 107.4 (1 F, d). IR
(neat): n 1751 (C=O) cmꢀ1. Anal. Calcd for C9H13ClF2O2:
C, 47.69; H, 5.78. Found C, 48.36; H, 5.72.
J = 297.9 Hz), 171.64. 19F NMR (CDCl3): d 103.1 (1 F, d,
J = 168.9 Hz), 103.8 (1 F, d). IR (neat): n 1735 (C=O) cmꢀ1
Anal. Calcd for C8H11ClF2O2: C, 45.19; H, 5.21. Found C,
44.91; H, 5.56.
.
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14.5 Hz), 2.46–2.68 (2 H, m), 4.19 (1 H, d, J = 12.4 Hz),
4.43 (1 H, d, J = 12.4 Hz). 13C NMR (CDCl3): d 8.18 (t,
J = 1.8 Hz), 24.59 (t, J = 2.3 Hz), 27.47 (t, J = 2.0 Hz),
27.66, 47.29 (t, J = 19.5 Hz), 68.59 (t, J = 3.0 Hz), 132.96 (t,
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