The polar effect on the regiochemistry of nucleophilic substitution of trifluoromethylated π-allylpalladium complex

Article abstract of DOI:10.1016/S0022-328X(03)00262-6

Allylic nucleophilic substitution of trifluoromethyl-group substituted cinnamyl carbonate with diethyl malonate anion in the presence of palladium complex catalyst gave regio- and stereoselectively the S_N2′ product. The regiochemistry caused by

Full text of DOI:10.1016/S0022-328X(03)00262-6

Journal of Organometallic Chemistry 676 (2003) 43ꢀ48
/
www.elsevier.com/locate/jorganchem
The polar effect on the regiochemistry of nucleophilic substitution of
trifluoromethylated p-allylpalladium complex
Takashi Okano *, Hiroyoshi Matsubara, Takahiro Kusukawa 1, Makoto Fujita1
Department of Applied Chemistry, Graduate School of Engineering, and Center for Integrated Research in Science and Engineering, Nagoya University,
Chikusa-ku, Nagoya 464-8603, Japan
Received 19 November 2002; received in revised form 17 March 2003; accepted 20 March 2003
Abstract
Allylic nucleophilic substitution of trifluoromethyl-group substituted cinnamyl carbonate with diethyl malonate anion in the
presence of palladium complex catalyst gave regio- and stereoselectively the SN2? product. The regiochemistry caused by the polar
effect of trifluoromethyl group was opposite to the methylated cinnamyl substrate in a similar steric environment. The sterically
more hindered mesityl and tert-butyl substrates than phenyl derivative also gave the products reacted at the more hindered sites.
Although o-substituted substrates expecting intramolecular coordination to affect regiochemistry were examined, no alternative
regioisomers were detected.
# 2003 Elsevier Science B.V. All rights reserved.
Keywords: p-Allylpalladium complexes; Regiochemistry; Trifluoromethyl group; s-Acceptor
1. Introduction
workers reported several trifluoromethylated allyl acet-
ates and carbonates regioselectively gave the products
[6]. Nevertheless, it still remains unclear if the polar
effect prevails over the steric effect. In the course of our
investigation of stereoselective synthesis of aliphatic
linear molecules with a trifluoromethyl group for the
building block of fluorine-containing functional materi-
als [7], we found that the regiochemistry is predomi-
nantly determined by the polar effect. In this paper, we
report the regioselective nucleophilic substitution of
trifluoromethylated allyl carbonates (Scheme 1).
Nucleophilic substitution reactions of p-allylpalla-
dium complexes with soft carbon nucleophiles have
attracted much attention as useful transformations for
the introduction of new carbonÃ
/carbon bonds into
allylic oxygenated compounds [1]. Since the reaction
proceeds through p-allylpalladium complexes as the
intermediates, a problem of regiochemistry arising
from unsymmetrically substituted substrates is which
terminal carbon is attacked by the soft carbon nucleo-
philes such as enolate anions [2]. Generally, the least-
substituted carbons are attacked by the nucleophiles [3].
A conjugated carbonyl group (p-acceptor) on a terminal
carbon also controls the regiochemistry to form a new
2. Results and discussion
CÃ
/
C bond at the other terminal carbon [4]. Alterna-
Trifluoromethylated carbonates 1aꢀ
starting from trifluoromethylenones 2aꢀ
Section 3 (vide infra).
Nucleophilic substitution of carbonate 1a with diethyl
malonateꢀNaOEt was firstly examined using Pd(PPh3)4
/
f were prepared
tively, p-donor/s-acceptor alkoxy substituent directs the
substitution to the oxygenated terminal [5]. For a pure
s-acceptor trifluoromethyl group, Kobayashi and co-
/
f as described in
/
as a Pd(0) catalyst. While a mixture of E/Z isomers of
SN2? products were given, the yield was low. After
several Pd catalysts were examined, allylpalladium
complex [(h3-CH2CHCH2)PdCl]2 (4) was found to be
useful as an effective allylation catalyst. Carbonate 1a
* Corresponding author. Tel./fax: ꢁ81-52-7895485.
E-mail address: okano@cirse.nagoya-u.ac.jp (T. Okano).
1
Present address: Department of Applied Chemistry, Graduate
School of Engineering, The University of Tokyo, 7-3-1 Hongo,
Bunkyo-ku, Tokyo 113-8656, Japan.
/
0022-328X/03/$ - see front matter # 2003 Elsevier Science B.V. All rights reserved.
doi:10.1016/S0022-328X(03)00262-6

44
T. Okano et al. / Journal of Organometallic Chemistry 676 (2003) 43ꢀ48
/
In general, the steric effect mainly determines the
regiochemistry of palladium-assisted nucleophilic sub-
stitution of allyl esters [3]. There are several reports
describing nucleophilic substitution of structurally re-
lated methyl derivative 6 with sodium dimethyl mal-
onate in the presence of p-palladium complex catalyst 4,
and the major product was alternative regioisomer 7
[10]. In this case, the regiochemistry was controlled by
the difference in the steric bulk of substituents on the
terminal carbons of the p-allylpalladium complex, and
the less hindered methylated carbon terminal was
attacked by the malonate nucleophile. The size of a
Scheme 1.
was reacted with diethyl malonateꢀNaOEt in the
/
presence of 10% of allylpalladium 4 and 20% of PPh3
to give 5a stereoselectively in 58% yield with a small
amount of alcohol 3a, which was presumably yielded by
the transesterification of 1a with NaOEt. The regio- and
1
trifluoromethyl group (A valueꢂ
DG8 for axialꢀequatorial cyclohexane interconversion
[11]) is considerably larger than that of a methyl group
(A valueꢂ
1.7 kcal molꢃ1), but it is still somewhat
smaller than that of a phenyl group (A valueꢂ2.8 kcal
/
2.4ꢀ
/
2.5 kcal molꢃ1
:
stereochemistry were confirmed by the H-NMR spec-
trum, in which a vinylic proton signal (d 5.65; JHꢀH
ꢂ
/
ꢃ
/
/
15.9 and JHꢀF 6.3 Hz) revealed that the oxygenated
ꢂ
/
terminal carbon bearing the trifluoromethyl group was
converted to an unsaturated carbon. In the Pd(0)-
assisted nucleophilic substitution reaction of allyl car-
bonates with malonates, mechanistically, addition of
base is not necessary because of the formation of
alkoxide anion during the palladium complexation to
allyl carbonates [8]. However, the reaction under the
above-mentioned conditions without addition of NaOEt
resulted in no change in carbonate 1a. Just after the
/
/
molꢃ1). The absence of production of the regioisomer
of 5a suggests that for the trifluoromethylated p-
allylpalladium complex formed from 1a the regiochem-
istry is determined by the polar effect of the strongly
electron-withdrawing s-acceptor, CF3-group, and the
nucleophile attacks at the terminal carbon with the more
hindered phenyl group.
addition of an excess amount of NaOEt, the reaction
mixture turned brown and the product 5a was detected
by TLC analysis. This suggests the strongly basic
conditions are necessary for the formation of trifluor-
omethylated palladium p-allyl complex from 1a. When
NaH was used as base to generate enolate, the yield of
5a was lower (38%) than alkoxide base. Kitazume et al.
have already reported the difficulty of generation of p-
palladium complexes from this type of trifluoromethy-
lated aryl starting materials, but seemingly they used no
strong base [9]. Finally, to avoid transesterification of 1a
with NaOEt, sterically hindered NaOtBu was used and
5a was obtained regio- and stereoselectively in 71%
yield.
To confirm importance of the polar effect, carbonates
1bꢀd with more sterically hindered reaction sites were
/
examined. As shown in Scheme 2, methyl groups at
ortho position of the phenyl ring (1b,c) have no effect to
determine the regiochemistry. Furthermore, even tert-
butyl derivative 1d gave the more sterically crowded
product 5d. In order to control the regiochemistry of the
nucleophilic substitution, intramolecular coordination
Scheme 2.

T. Okano et al. / Journal of Organometallic Chemistry 676 (2003) 43ꢀ
/48
45
to palladium has been employed [12]. Although o-
alkoxy derivatives 1e,f were employed in anticipation
of intramolecular coordination of oxygen atom, only the
normal products 5e,f were also given.
internal CF3COOC2H5 whose chemical shift was set at
75.75 ppm downfield (d) from internal CFCl3 in
CDCl3.
ꢃ
/
The polar effect of a trifluoromethyl group for the
regiochemical selection of nucleophilic substitution of
cinnamyl carbonates prevails over the steric effect,
which has been recognized as the major factor for the
regiochemical control in palladium-assisted nucleophilic
substitution. For the regiospecific substitution of the
allylic system with a p-acceptor (an alkoxycarbonyl
group), an unsymmetrical p-palladium complex or s-
complex intermediate was invoked [4a]. In the non-
conjugated trifluoromethyl system, these unsymmetrical
complex structures are also conceivable. In the palla-
dium catalyzed allyl nucleophilic substitution, both s-
and p-acceptors act as the regio-controlling substituents
3.2. Preparation of carbonate substrates (1aꢀf)
/
Trifluoromethylated carbonates 1aꢀ
starting from the NaBH4ꢀCeCl3 reduction of the
corresponding (E)-trifluoromethylenones 2aꢀf followed
by deprotonation of the resulting alcohols 3aꢀf with
/f were prepared
/
/
/
NaH and the reaction with ethyl chlorocarbonate
(Scheme 3). The isolate yields of tert-butyl derivatives
2d and 1d were relatively lower than corresponding aryl
derivatives due to their volatility.
3.2.1. (E)-1,1,1-Trifluoro-4-(o-tolyl)-3-buten-2-ol (3b)
To a stirred mixture of ketone 2b (3.63 g, 15.7 mmol)
and cerium chloride heptahydrate (5.96 g, 16 mmol) in
methanol (40 ml), NaBH4 (605 mg, 16.0 mmol) was
added in portions at 0 8C. The mixture was stirred at
room temperature for 10 min, and then aqueous NH4Cl
solution was added into the mixture. The mixture was
extracted with hexane and Et2O. The combined extracts
were dried over MgSO4 and the solvents were removed
under reduced pressure. The residue was chromato-
to afford the allylic products with a new CÃ
/C bond at
the terminal carbon opposite to the electron-withdraw-
ing group.
3. Experimental
3.1. General
graphed on a silica gel column (5:2 hexaneꢀ
/
CH2Cl2) to
obtain pure 3b as colorless solid: 3.30 g (90%); mp:
1H- and 13C-NMR spectra were collected in CDCl3 in
the presence of Me4Si as an internal standard at 300 and
75.4 MHz, respectively. 19F-NMR spectra (282 MHz)
were recorded in CDCl3, and referenced based on
1
51.0ꢀ
(m, 1H), 4.658 (tq, Jꢂ
15.9, 6.3 Hz, 1H), 7.096 (d, Jꢂ
/
51.6 8C; H-NMR (CDCl3): d 2.371 (s, 3H), 2.48
6.3, 6.1 Hz, 1H), 6.092 (dd, Jꢂ
15.9 Hz, 1H), 7.15ꢀ7.25
/
/
/
/
Scheme 3.

46
T. Okano et al. / Journal of Organometallic Chemistry 676 (2003) 43ꢀ48
/
(m, 3H), 7.456 (dd, Jꢂ
(CDCl3): d 19.65, 71.75 (q, Jꢂ
Hz), 124.25 (q, Jꢂ281 Hz), 125.92, 126.23, 128.56,
130.44, 134.29, 134.51, 135.97; 19F-NMR (CDCl3): d
/
6.0, 2.4 Hz, 1H); 13C-NMR
32 Hz), 121.95 (q, Jꢂ
3.2.5. (E)-1,1,1-Trifluoro-4-[o-
(methoxymethoxy)phenyl]-3-buten-2-ol (3f)
Alcohol 3f was obtained as above: colorless solid,
/
/
2
/
yield 87%; m.p.: 75.1ꢀ
2.345 (d, Jꢂ5.7 Hz, 1H), 3.493 (s, 3H), 4.648 (tqd, Jꢂ
6.8, 6.1, 1.8 Hz, 1H), 5.231 (s, 2H), 6.245 (dd, Jꢂ16.2,
6.9 Hz, 1H), 7.003 (td, Jꢂ7.5, 1.2 Hz, 1H), 7.118 (dd,
Jꢂ7.5, 1.2 Hz, 1H), 7.199 (dd, Jꢂ16.2, 1.8 Hz, 1H),
7.260 (td, Jꢂ7.7, 1.5 Hz, 1H), 7.471 (dd, Jꢂ7.5, 1.5
Hz); 13C-NMR (CDCl3): d 56.22, 72.04 (q, Jꢂ
32 Hz),
94.63, 114.75, 121.35 (q, Jꢂ2 Hz), 121.97, 124.32 (q,
Jꢂ
281 Hz), 125.05, 127.25, 129.88, 131.34, 154.76; 19F-
NMR (CDCl3): d ꢃ 6.1 Hz); EI-MS m/z
/
76.5 8C; 1H-NMR (CDCl3): d
ꢃ
/
79.57 (d, Jꢂ
/
6.1 Hz); EI-MS m/z (%) 217 (12), 216
/
/
(Mꢁ, 86), 147 (100), 129 (52), 115 (37), 105 (27), 91 (28).
Anal. Calc. for C11H11F3O: C, 61.11; H, 5.13. Found: C,
61.08; H, 5.24%.
/
/
/
/
/
/
/
/
3.2.2. (E)-4-Mesityl-1,1,1-trifluoro-3-buten-2-ol (3c)
Alcohol 3c was obtained as above: colorless oil, yield
76%; m.p.: 1H-NMR (CDCl3): d 2.253 (s, 6H), 2.268 (s,
/
/
79.56 (d, Jꢂ
/
(%) 263 (6), 262 (Mꢁ, 48), 230 (44), 131 (100), 91 (31),
51 (23). Anal. Calc. for. C12H13F3O3: C, 54.96; H, 5.00.
Found: C, 54.97; H, 5.16%.
3H), 4.639 (sex, Jꢂ
1 Hz), 6.838 (d, Jꢂ
NMR (CDCl3): d 20.75, 21.04, 71.87 (q, Jꢂ
124.21 (q, Jꢂ281 Hz), 125.93 (q, Jꢂ2 Hz), 126.28,
132.13, 134.27, 135.75, 136.97; 19F-NMR (CDCl3): d
/
5.9 Hz, 1H), 5.710 (dd, Jꢂ
16.2 Hz, 1H), 6.869 (s, 3H); 13C-
32 Hz),
/
16.2, 6.5,
/
/
/
/
3.2.6. Ethyl (E)-3-phenyl-1-(trifluoromethyl)allyl
carbonate (1a)
ꢃ
/
80.28 (d, Jꢂ
/
6.1 Hz); EI-MS m/z (%) 245 (14, Mꢁꢁ
/
1), 244 (100, Mꢁ), 210 (11), 176 (10), 175 (75), 157 (39),
145 (25), 142 (13), 133 (36), 130 (15), 129 (22), 128 (23),
115 (17), 105 (11), 91 (19), 87 (149, 80 (11), 77 (19), 65
(11), 55 (93), 51 (12). Anal. Calc. for C13H15F3O: C,
63.93; H, 6.19. Found: C, 63.87; H, 6.24%.
To a stirred suspension of NaH (60% oil dispersion;
396 mg, 10.0 mmol) in anhydrous THF (30 ml) at 0 8C
under Ar atmosphere, a solution of alcohol 3a (2.02 g,
10.0 mmol) in THF (5 ml) was added dropwise in 1 h,
and then ethyl chloroformate (6.51 g, 60.0 mmol) was
added in one portion. After stirring the mixture for 24 h,
water was added and the mixture was extracted with
CHCl3. The combined extracts were washed successively
with 1 M HCl, water, and sat. aq. NaHCO3 solution.
The CHCl3 solution was dried over MgSO4. The
solvents were removed under reduced pressure. The
residue was chromatographed on a silica gel column (1:1
3.2.3. (E)-1,1,1-Trifluoro-5,5-dimethyl-3-buten-2-ol
(3d)
Alcohol 3d was obtained as above as volatile colorless
oil: yield 41%; bp 65 8C (17 mmHg); 1H-NMR (CDCl3):
d 1.047 (s, 9H), 2.2 (br s, 1H), 4.379 (quintet of d, Jꢂ
6.7, 1.2 Hz, 1H), 5.416 (dd, Jꢂ15.9, 6.7 Hz, 1H), 5.981
(dd, Jꢂ
15.9, 1.2 Hz, 1H); 19F-NMR (CDCl3): d
75.23 (d, Jꢂ6.2 Hz); EI-MS m/z (%) 164 (10,
Mꢁꢃ
H2O), 149 (17), 113 (16), 91 (20), 83 (34), 77
/
hexaneꢀ
g (94%); 1H-NMR (CDCl3): d 1.348 (t, Jꢂ
4.274 (q, Jꢂ7.2 Hz, 2H), 5.629 (dq, Jꢂ
1H), 6.142 (dd, Jꢂ16.0 Hz, 7.8 Hz, 1H), 6.913 (d, Jꢂ
16.0 Hz, 1H), 7.29ꢀ7.40 (m, 3H), 7.41ꢀ7.46 (m, 2H);
13C-NMR (CDCl3): d 14.10, 65.20, 74.72 (q, Jꢂ
34 Hz),
116.69 (q, Jꢂ2 Hz), 122.88 (q, Jꢂ280 Hz), 127.08,
128.74, 129.15, 134.83, 139.20, 153.56; 19F-NMR
6.1 Hz); EI-MS m/z (%)
/
CH2Cl2) to obtain pure 1a as colorless oil: 2.57
7.2 Hz, 3H),
7.8, 6.1 Hz,
/
/
/
/
/
ꢃ
/
/
/
/
/
/
/
(21), 69 (45), 67 (12), 65 (17), 63 (16), 59 (11), 57 (11), 55
(80), 51 (21), 43 (100).
/
/
/
(CDCl3): d ꢃ
/
77.21 (d, Jꢂ
/
3.2.4. (E)-4-(o-Anisyl)-1,1,1-trifluoro-3-buten-2-ol
(3e)
Alcohol 3e was obtained as above: colorless solid,
275 (2), 274 (Mꢁ, 12), 254 (59), 201 (28), 185 (35), 165
(35), 134 (51), 133 (100), 115 (91). Anal. Calc. for
C13H13F3O3: C, 56.94; H, 4.78. Found: C, 56.94; H,
4.95%.
yield 75%; m.p.: 64.5ꢀ
2.260 (d, Jꢂ6 Hz, 3H), 3.868 (s, 3H), 4.637 (dqd, Jꢂ
7.1, 6.1, 6 Hz, 1H), 6.258 (dd, Jꢂ16.2, 7.1 Hz, 1H),
6.898 (dd, Jꢂ7.5, 0.9 Hz, 1H), 6.951 (ddd, Jꢂ7.7, 6.6,
0.9 Hz, 1H), 7.171 (d, Jꢂ16.2 Hz, 1H), 7.292 (ddd, Jꢂ
7.5, 6.6, 1.8 Hz, 1H), 7.452 (dd, Jꢂ7.7, 1.8 Hz, 1H);
13C-NMR (CDCl3): d 55.43, 72.13 (q, Jꢂ
32 Hz),
110.96, 120.68, 121.20 (q, Jꢂ2 Hz), 124.25, 124.34 (q,
Jꢂ
281 Hz), 127.46, 129.87, 131.59, 157.08; 19F-NMR
(CDCl3): d ꢃ
/
65.5 8C; 1H-NMR (CDCl3): d
/
/
/
3.2.7. Ethyl (E)-3-(o-tolyl)-1-(trifluoromethyl)allyl
/
/
carbonate (1b)
1
Carbonate 1b was obtained as above: yield 91%; H-
/
/
/
NMR (CDCl3): d 1.351 (t, Jꢂ
3H), 4.278 (q, Jꢂ7.2 Hz, 2H), 5.636 (dq, Jꢂ
Hz, 1H), 6.142 (dd, Jꢂ16.0, 8.0 Hz, 1H), 7.10ꢀ7.24 (m,
4H), 7.455 (dd, Jꢂ
7.0, 2.1 Hz, 1H); 13C-NMR (CDCl3):
d 14.15, 19.70, 65.20, 74.91 (q, Jꢂ34 Hz), 118.11 (q,
Jꢂ1 Hz), 122.90 (q, Jꢂ280 Hz), 126.03, 126.28,
128.97, 130.52, 134.09, 136.25, 137.28, 153.59; 19F-
NMR (CDCl3): d ꢃ77.23 (d, Jꢂ6.1 Hz); EI-MS m/z
/7.2 Hz, 3H), 2.371 (s,
/
/
/8.0, 6.1
/
/
/
/
/
/
79.52 (d, Jꢂ
/
6.1 Hz); EI-MS m/z (%) 233
/
(12), 232 (Mꢁ, 100), 163 (85), 121 (140), 107 (28), 91
(40), 77 (27), 55 (61). Anal. Calc. for C11H11F3O2: C,
56.90; H, 4.77. Found: C, 57.08; H, 4.91%.
/
/
/
/

T. Okano et al. / Journal of Organometallic Chemistry 676 (2003) 43ꢀ
/48
47
(%) 289 (2), 288 (Mꢁ, 13), 199 (24), 198 (21), 147 (20),
129 (100), 125 (32). Anal. Calc. for C14H15F3O3: C,
58.33; H, 5.24. Found: C, 58.45; H, 5.45%.
7.001 (t, Jꢂ
7.22ꢀ7.31 (m, 2H), 7.469 (dd, Jꢂ
NMR (CDCl3): d 14.12, 56.23, 75.30 (q, Jꢂ
114.79, 117.33 (q, Jꢂ2 Hz), 119.22 (q, Jꢂ280 Hz),
121.92, 124.58, 127.51, 130.29, 134.41, 153.60, 155.01;
/
7.5 Hz, 1H), 7.121 (d, Jꢂ
/
8.0 Hz, 1H),
/
/
7.5 Hz, 1H); 13C-
/33 Hz),
/
/
3.2.8. Ethyl (E)-3-mesityl-1-(trifluoromethyl)allyl
carbonate (1c)
1
Carbonate 1c was obtained as above: yield 76%; H-
19F-NMR (CDCl3): d ꢃ
/
77.23 (d, Jꢂ6.1 Hz); EI-MS
/
m/z (%) 335 (2), 334 (Mꢁ, 8), 245 (5), 213 (10), 200 (21),
199 (9), 132 (10), 131 (100). Anal. Calc. for C15H17F3O5:
C, 53.89; H, 5.13. Found: C, 53.79; H, 5.05%.
NMR (CDCl3): d 1.266 (t, Jꢂ
6H), 2.191 (s, 3H), 4.206 (q, Jꢂ7.3 Hz, 2H), 5.47ꢀ
(m, 2H), 6.789 (s, 2H), 6.847 (d, Jꢂ
15.1 Hz, 1H); 13C-
NMR (CDCl3): d 14.22, 20.65, 21.04, 65.16, 74.98 (q,
Jꢂ34 Hz), 122.15 (q, Jꢂ2 Hz), 122.83 (q, Jꢂ280 Hz),
128.59, 131.71, 135.76, 137.24, 137.50, 153.40; 19F-
NMR (CDCl3): d ꢃ77.87 (d, Jꢂ6.1 Hz); EI-MS m/z
(%) 317 (5, Mꢁꢁ1), 316 (26, Mꢁ), 227 (26), 226 (25),
/7.3 Hz, 3H), 2.165 (s,
/
/
5.64
/
/
/
/
3.2.12. Ethyl (E)-2-ethoxycarbonyl-6,6,6-trifluoro-3-
phenyl-4-hexenoate (5a)
/
/
To a mixture of carbonate 1a (54 mg, 0.20 mmol),
allylpalladium complex 4 (7.3 mg, 20 mmol), triphenyl-
phosphine (10.4 mg, 40 mmol) in anhydrous THF (1 ml),
a mixture of diethyl malonate (96 mg, 0.30 mmol) and
NaOtBu (58 mg, 0.60 mmol) in THF (0.6 ml) was added
under Ar atmosphere. The resulting mixture was stirred
at room temperature for 1 h, and then quenched with
water. The reaction mixture was extracted with CHCl3.
The combined extracts were dried over MgSO4, and the
solvents were removed under reduced pressure. The
residue was chromatographed on a silica gel column to
/
210 (33), 158 (14), 157 (100), 143 (13), 142 (18), 129 (13),
128 (149, 120 (15), 91 (12). Anal. Calc. for C16H19F3O3:
C, 60.75; H, 6.05. Found: C, 60.65; H, 6.12%.
3.2.9. (E)-4,4-Dimethyl-1-(trifluoromethyl)-2-pentenyl
ethyl carbonate (1d)
1
Carbonate 1d was obtained as above: yield 43%; H-
NMR (CDCl3): d 1.043 (s, 9H), 1.340 (t, Jꢂ
3H), 4.258 (q, Jꢂ7.2 Hz, 2H), 5.33ꢀ5.47 (m, 2H), 6.076
(d, Jꢂ 78.27 (d,
15.0 Hz, 1H); 19F-NMR (CDCl3): d ꢃ
Jꢂ OCOOC2H5),
6.1 Hz); EI-MS m/z (%) 165 (3, Mꢁꢃ
/
7.2 Hz,
/
/
/
/
1
give pure ester 5a as pale yellow oil: 51 mg (74%); H-
/
/
NMR (CDCl3): d 1.002 (t, Jꢂ
7.2 Hz, 3H), 3.839 (d, Jꢂ10.8 Hz, 1H), 3.969 (q, J ꢂ
7.2 Hz, 2H), 4.16ꢀ4.26 (m, 3H), 5.656 (dqd, Jꢂ15.9,
6.1, 1.8 Hz, 1H), 6.566 (ddq, Jꢂ15.9, 8.1, 1.0 Hz, 1H),
7.19ꢀ
7.37 (m, 5H); 13C-NMR (CDCl3): d 13.71, 13.98,
47.35, 56.77, 61.65, 61.94, 120.26 (q, Jꢂ33 Hz), 122.64
(q, Jꢂ269 Hz), 127.79, 128.12, 128.91, 137.80, 139.45
(q, Jꢂ
6 Hz), 166.79, 167.32; 19F-NMR (CDCl3): d
64.85 (d, Jꢂ
6.1 Hz); EI-MS m/z (%) 344 (Mꢁ, 0.6),
/
7.2 Hz, 3H), 1.276 (t, Jꢂ
/
163 (12), 162 (16), 161 (20), 160 (14), 159 (15), 127 (14),
126 (23), 125 (33), 124 (27), 123 (24), 91 (29), 90 (13), 87
(15), 78 (13), 64 (14), 63 (54), 61 (649, 60 (100), 59 (97),
54 (12), 53 (13). Anal. Calc. for C11H17F3O3: C, 51.97;
H, 6.74. Found: C, 52.00; H, 6.71%.
/
/
/
/
/
/
/
/
3.2.10. (E)-3-(o-Anisyl)-1-(trifluoromethyl)allyl ethyl
carbonate (1e)
1
Carbonate 1e was obtained as above: yield 75%; H-
/
ꢃ
/
/
271 (100), 243 (26), 201 (44), 185 (43), 173 (28), 165 (40),
129 (24), 128 (22), 115 (26). Anal. Calc. for C17H19F3O4:
C, 59.30; H, 5.56. Found: C, 59.22; H, 5.44%.
NMR (CDCl3): d 1.343 (t, Jꢂ
3H), 4.266 (q, Jꢂ7.2 Hz, 2H), 5.630 (dq, Jꢂ
Hz, 1H), 6.215 (dd, Jꢂ16.1, 8.1 Hz, 1H), 6.888 (dd, Jꢂ
8.4, 1.0 Hz, 1H), 6.942 (td, Jꢂ7.5, 1.0 Hz, 1H), 7.216
(dd, Jꢂ16.1 Hz, 1H), 7.296 (ddd, Jꢂ8.4, 7.5, 1.5 Hz,
1H), 7.440 (dd, Jꢂ
7.5, 1.5 Hz, 1H); 13C-NMR (CDCl3):
d 14.10, 55.40, 75.43 (q, Jꢂ33 Hz), 110.97, 117.10 (q,
Jꢂ2 Hz), 120.61, 122.99 (q, Jꢂ280 Hz), 123.74,
127.79, 130.27, 130.27, 134.65, 153.59, 157.36; 19F-
6.1 Hz); EI-MS m/z
/7.2 Hz, 3H), 3.860 (s,
/
/8.1, 6.1
/
/
/
/
/
/
3.2.13. Ethyl (E)-2-ethoxycarbonyl-6,6,6-trifluoro-3-(o-
/
tolyl)-4-hexenoate (5b)
1
Ester 5b was obtained as above: yield 51%; H-NMR
/
/
(CDCl3) 0.969 (t, Jꢂ
3H), 2.397 (s, 3H), 3.919 (d, Jꢂ
Jꢂ7.2 Hz, 2H), 4.241 (q, Jꢂ7.2 Hz, 2H), 4.488 (dddq,
Jꢂ11.3, 7.8, 1.5, 1.2 Hz, 1H), 5.573 (dqd, Jꢂ15.9, 6.1,
1.5 Hz, 1H), 6.458 (ddq, Jꢂ15.9, 7.8, 2.4 Hz, 1H),
7.26ꢀ
7.14 (m, 4H); 13C-NMR (CDCl3): d 13.81, 14.16,
19.80, 42.76, 51.44, 61.15, 61.78, 120.20 (q, Jꢂ34 Hz),
122.86 (q, Jꢂ270 Hz), 126.66, 126.79, 127.65, 131.18,
136.15, 136.87, 139.56 (q, Jꢂ
6 Hz), 166.97, 167.75; 19F-
6.1 Hz); EI-MS m/z
/
7.2 Hz, 3H), 1.291 (t, Jꢂ
/
7.2 Hz,
NMR (CDCl3): d ꢃ
/
77.22 (d, Jꢂ
/
/11.3 Hz, 1H), 3.949 (q,
(%) 305 (16), 304 (Mꢁ, 96), 284 (33), 231 (49), 215 (100),
163 (38), 145 (33), 131 (48), 121 (75), 108 (74), 107 (66).
Anal. Calc. for C14H15F3O4: C, 55.26; H, 4.97. Found:
C, 55.19; H, 4.92%.
/
/
/
/
/
/
/
3.2.11. Ethyl (E)-3-[o-(methoxymethyl)phenyl]-1-
/
(trifluoromethyl)allyl carbonate (1f)
Carbonate 1f was obtained as above: yield 81%; H-
/
1
NMR (CDCl3): d ꢃ
/
64.75 (d, Jꢂ
/
NMR (CDCl3): d 1.346 (t, Jꢂ
3H), 4.272 (q, Jꢂ7.2 Hz, 2H), 5.233 (s, 2H), 5.644 (dq,
Jꢂ8.4, 6.1 Hz, 1H), 6.198 (dd, Jꢂ16.5, 8.4 Hz, 1H),
/7.2 Hz, 3H), 3.492 (s,
(%) 358 (Mꢁ, 2), 199 (31), 179 (28), 164 (34), 129 (100),
128 (28), 115 (45), 91 (38). Anal. Calc. for C18H21F3O4:
C, 60.33; H, 5.91. Found: C, 60.16; H, 5.91%.
/
/
/

48
T. Okano et al. / Journal of Organometallic Chemistry 676 (2003) 43ꢀ48
/
3.2.14. Ethyl (E)-2-ethoxycarbonyl-6,6,6-trifluoro-3-
mesityl-4-hexenoate (5c)
Hz, 3H), 3.495 (s, 3H), 3.940 (q, Jꢂ
(d, Jꢂ10.8 Hz, 1H), 4.219 (q, Jꢂ7.2 Hz, 2H), 4.438
(dd, Jꢂ10.8, 8.7 Hz, 1H), 5.236 (s, 2H), 5.657 (dq, Jꢂ
16.2, 6.1 Hz, 1H), 6.668 (ddq, Jꢂ15.6, 7.8, 1.5 Hz, 1H),
6.945 (t, Jꢂ7.8 Hz, 1H), 7.110 (d, Jꢂ8.4 Hz, 1H),
7.152 (dd, Jꢂ7.8, 1.8 Hz, 1H), 7.221 (ddd, Jꢂ8.4, 7.8,
1.8 Hz, 1H); 13C-NMR (CDCl3): d 13.65, 13.96, 43.91,
54.67, 56.10, 61.39, 61.74, 94.18, 114.23, 120.01 (q, Jꢂ
33 Hz), 121.81, 122.83 (q, Jꢂ270 Hz), 126.22, 128.78 (q,
Jꢂ
7 Hz), 129.05, 129.80, 154.95, 167.08, 167.71; 19F-
NMR (CDCl3): d ꢃ 6.1 Hz); EI-MS m/z
/
7.2 Hz, 2H), 4.145
/
/
1
Ester 5c was obtained as above: yield 33%; H-NMR
/
/
(CDCl3) 1.268 (t, Jꢂ
3H), 2.228 (s, 3H), 2.32 (br s, 6H), 4.122 (d, Jꢂ
1H), 4.203 (q, Jꢂ7.2 Hz, 2H), 4.278 (q, Jꢂ7.2 Hz, 2H),
4.72ꢀ4.83 (m, 1H), 5.408 (dqd, Jꢂ14.7, 6.3, 2.1 Hz,
1H), 6.588 (ddq, Jꢂ15.9, 4.2, 2.4 Hz, 1H), 6.817 (s, 2H);
19F-NMR (CDCl3): d ꢃ
65.03 (br s); EI-MS m/z (%)
/
7.2 Hz, 3H), 1.308 (t, Jꢂ/7.2 Hz,
/
/11.7 Hz,
/
/
/
/
/
/
/
/
/
/
/
/
386 (4, Mꢁ), 368 (19), 267 (25), 239 (12), 238 (11), 228
(15), 227 (100), 226 (44), 212 (12), 211 (16), 158 (10), 157
(58), 143 (17), 142 (13), 141 (11), 119 (41), 91 (13). Anal.
Calc. for C20H25F3O4: C, 62.17; H, 6.52. Found: C,
62.21; H, 6.73%.
/
/
64.72 (d, Jꢂ
/
(%) 405 (5), 404 (Mꢁ, 20), 314 (12), 313 (56), 285 (22),
267 (31), 244 (22), 241 (100), 219 (22), 213 (30), 160 (28),
131 (39). Anal. Calc. for C19H23F3O6: C, 56.43; H, 5.73.
Found: C, 56.22; H, 6.00%.
3.2.15. Ethyl (E)-3-tert-butyl-2-ethoxycarbonyl-6,6,6-
trifluoro-4-hexenoate (5d)
1
Ester 5d was obtained as above: yield 53%; H-NMR
(CDCl3) 0.925 (s, 9H), 1.255 (t, Jꢂ
Jꢂ7.2 Hz, 3H), 2.846 (dd, Jꢂ11.1, 6.3 Hz, 1H), 3.612
(d, Jꢂ6.3 Hz, 1H), 4.137 (q, Jꢂ7.2 Hz, 2H), 4.195 (q,
Jꢂ7.1 Hz, 2H), 5.701 (dq, Jꢂ15.3, 6.3 Hz, 1H), 6.481
(ddq, Jꢂ
15.3, 8.7, 1.8 Hz, 1H); 19F-NMR (CDCl3): d
65.32 (d, Jꢂ6.0 Hz); EI-MS m/z (%) 309 (2,
Mꢁꢃ
CH3), 268 (59), 232 (11), 222 (15), 217 (12), 195
(22), 194 (15), 176 (12), 125 (10), 115 (11), 97 (14), 87
(10), 57 (100). Anal. Calc. for C15H23F3O4: C, 55.55; H,
7.15. Found: C, 55.53; H, 7.17%.
/
7.1 Hz, 3H), 1.250 (t,
References
/
/
/
/
[1] (a) J. Tsuji, Palladium Reagents and Catalysis: Innovations in
Organic Synthesis, Wiley and Sons, New York, 1995;
(b) R.F. Heck, Palladium Reagents in Organic Syntheses,
Academic Press, London, 1985.
/
/
/
ꢃ
/
/
/
[2] B.M. Trost, P.E. Strege, J. Am. Chem. Soc. 97 (1975)
2534.
[3] (a) G. Conisiglio, R.M. Waymouth, Chem. Rev. 89 (1989)
257;
(b) E. Keinan, M. Sahari, Chem. Commun. (1984) 648.
[4] (a) R. Tanikaga, T.X. Jun, A. Kaji, J. Chem. Soc. Perkin Trans. 1
(1990) 1185;
3.2.16. Ethyl (E)-3-(o-anisyl)-2-ethoxycarbonyl-6,6,6-
trifluoro-4-hexenoate (5e)
1
Ester 5e was obtained as above: yield 77%; H-NMR
(b) D.J. Collins, W.R. Jackson, R.N. Timms, Tetrahedron Lett.
17 (1973) 495.
[5] L. Dunkerton, J. Org. Chem. 47 (1982) 2812.
[6] Y. Hanzawa, S. Ishizawa, Y. Kobayashi, Chem. Pharm. Bull. 36
(1988) 4209.
(CDCl3): d 0.987 (t, Jꢂ
Hz, 3H), 3.858 (s, 3H), 3.943 (q, Jꢂ
(d, Jꢂ10.5 Hz, 1H), 4.205 (q, Jꢂ7.2 Hz, 2H), 4.4389
(dddq, Jꢂ
15.6, 6.1, 1.2 Hz, 1H), 6.458 (ddq, Jꢂ
1H), 6.875 (dd, Jꢂ
1.5 Hz, 1H), 7.141 (dd, Jꢂ
Jꢂ
8.4, 7.5, 1.5 Hz, 1H); 19F-NMR (CDCl3): d ꢃ
(d, Jꢂ
6.1 Hz); EI-MS m/z (%) 374 (Mꢁ, 10), 302 (15),
301 (88), 282 (13), 273 (20), 255 (18), 231 (38), 215 (100),
203 (13), 180 (13), 159 (12), 131 (13). Anal. Calc. for
C18H21F3O5: C, 57.75; H, 5.65. Found: C, 57.77; H,
5.55%.
/
7.2 Hz, 3H), 1.264 (t, Jꢂ
/
7.2
/7.2 Hz, 2H), 4.164
/
/
[7] T. Okano, H. Sugiura, M. Fumoto, H. Matsubara, T. Kusukawa,
M. Fujita, J. Fluorine Chem. 114 (2002) 91.
[8] J. Tsuji, I. Shimizu, I. Minami, Y. Ohashi, Tetrahedron Lett. 23
(1982) 4809.
/
10.4, 8.6, 1.5, 1.2 Hz, 1H), 5.667 (dqd, Jꢂ
/
/
15.6, 8.7, 2.1 Hz,
/
8.4, 1.5 Hz, 1H), 6.898 (dt, Jꢂ
7.5, 1.5 Hz, 1H), 7.246 (ddd,
64.71
/7.5,
[9] T. Sakamoto, K. Takahashi, T. Yamazaki, T. Kitazume, J. Org.
Chem. 64 (1999) 9467.
/
/
/
[10] (a) T. Hayashi, A. Yamamoto, T. Hagiwara, J. Org. Chem. 51
(1986) 723; T. Hayashi, T. Hagiwara, M. Konishi, M. Kumada, J.
Am. Chem. Soc. 105 (1983) 7767;
/
(b) U. Kazmaier, F.L. Zumpe, Angew. Chem. Int. Ed. 38 (1999)
1468;
(c) A. Togni, Tetrahedron Asymmetry 2 (1991) 683.
[11] E.L. Eliel, S.H. Wilen, Stereochemistry of Organic Compounds,
John Wiley and Sons, New York, 1994.
3.2.17. Ethyl (E)-2-ethoxycarbonyl-6,6,6-trifluoro-3-[o-
(methoxymethyl)phenyl]-4-hexenoate (5f)
1
Ester 5f was obtained as above: yield 31%; H-NMR
[12] (a) E.L. Eliel, S.H. Wilen, Stereochemistry of Organic Com-
pounds, John Wiley and Sons, New York, 1994;
(b) M.E. Krafft, M. Sugiura, K.A. Abboud, J. Am. Chem. Soc.
123 (2001) 9174.
(CDCl3): d 0.979 (t, Jꢂ
/
7.2 Hz, 3H), 1.272 (t, Jꢂ7.2
/