Mizoroki-heck reaction of (1-Fluorovinyl)methyldiphenylsilane with aryl iodides

Article abstract of DOI:10.1021/jo201720x

The Mizoroki-Heck reaction of (1-fluorovinyl)methyldiphenylsilane with a variety of aryl iodides was accomplished under the conditions composing Pd(OAc)₂, Ag₂CO₃ and MS 4 A in 1,4-dioxane to give the corresponding (E)-Β-ar

Full text of DOI:10.1021/jo201720x

NOTE
pubs.acs.org/joc
MizorokiꢀHeck Reaction of (1-Fluorovinyl)methyldiphenylsilane with
Aryl Iodides
Kensuke Hirotaki and Takeshi Hanamoto*
Department of Chemistry and Applied Chemistry, Saga University, Honjyo-machi 1, Saga 840-8502, Japan
S Supporting Information
b
ABSTRACT: The Mizoroki-Heck reaction of (1-fluorovinyl)-
methyldiphenylsilane with a variety of aryl iodides was accom-
plished under the conditions composing Pd(OAc)2, Ag2CO3 and
MS 4 Å in 1,4-dioxane to give the corresponding (E)-β-aryl-(α-
fluorovinyl)methyldiphenylsilanes with excellent stereoselectivity.
he MizorokiꢀHeck reaction has proven to be a powerful
tool for the arylation of olefins in organic synthesis.1
Some results are shown in Table 1, and the optimal conditions
were eventually obtained in entry 13. The reaction well pro-
ceeded giving the desired product 3a in 72% yield with excellent
stereoselectivity (E/Z = 98:2). The E/Z stereochemistry was
assigned on the basis of the coupling constant of 1H NMR and
19F NMR of the product 3a. The J value of 50.3 Hz between the
vinylic proton and the fluorine atom indicated the corresponding
E-configuration. The introduced aryl group is situated at the trans
position toward the bulky methyldiphenylsilyl group. This trans
relationship between the aryl and the silyl group is similar to that
of the aryl and acyl groups in the MizorokiꢀHeck reaction using
3-fluoro-3-buten-2-one.3d The reason for the excellent E-stereo-
selectivity should be attributed to the contribution of the stable
conformer A prior to the required syn elimination (Scheme 1).
It is worth noting that the combinatorial conditions of Pd-
(OAc)2 (10 mol %) and Ag2CO3 (3 equiv) in dioxane at 90 °C
are essential for the successful reaction. The use of other bases,
Pd sources, and different solvents uniformly failed to improve the
yield (entries 2ꢀ10). The lower loading of Ag2CO3 (1ꢀ2 equiv)
and Pd(OAc)2 (5 mol %) resulted in the lower yields (entries
14ꢀ16). Although the role of MS4 Å is not clear at present, it might
remove a trace amount of water probably generated from decom-
position of H2CO3 resulted from Ag2CO3 in the reaction mixture.
Table 2 shows the scope of the MizorokiꢀHeck reaction of
aryl iodides using 1. The results were almost independent of the
position of the aromatic ring as well as the nature of the sub-
stituents. The chemical yield of the reaction was typically good
to high. The stereoselectivity of the reaction was excellent
except for 3d.9 Functional groups such as esters, ethers, a nitro, a
cyano, and halogens were well tolerated. Unfortunately, no
heteroaryl iodides such as 2-iodothiophene and 2-iodopyridine
participated in the reaction. Moreover, 40-bromoacetophenone
as an aryl bromide was found to be unreactive for the reaction. In
these cases, both of the starting materials were almost recovered
intact.
T
Although a wide range of olefins containing various substituents
can participate in the reaction,2 very few reports concerning the
use of fluoroolefins are available.3 Additionally, the Mizorokiꢀ
Heck reaction of vinylsilanes is also understood to be difficult
because of its tendency toward elimination of the silyl moiety
instead of hydrogen.4 Hence, to the best our knowledge, there
exist no reports concerning the use of silylated fluoroolefins for
this reaction. Recently, much effort has been exerted to introduce
the fluorine into organic molecules owing to its remarkable
effects on their structure, stability, reactivity, and biological
activity.5 Consequently, the stereoselective synthesis of fluoro-
olefins containing a functional group also remains one of the
challenging subjects. We have recently reported an easy prepara-
tion of (1-fluorovinyl)methyldiphenylsilane and its application
for the construction of a variety of fluorovinyl compounds.6,7
From another synthetic point of view, this silane would be an
attractive candidate for the MizorokiꢀHeck reaction. We report
herein the first example of the MizorokiꢀHeck reaction of
silylated fluoroolefin and a synthetic application of the resulting
coupling products to transform the corresponding cis-β-fluoro-
styrene derivative.
Our investigation started by using (1-fluorovinyl)methyldi-
phenylsilane 1 and 40-iodoacetophenone 2a as a model com-
pound in order to explore the viability on the MizorokiꢀHeck
reaction. In our early experiment, the reaction in the presence of
10 mol % of Pd(OAc)2 and Ag2CO3 (3 equiv) in DMF at 25 °C
for 2 h led to the desired product 3a albeit in 25% yield and with
low stereoselectivity (E/Z = 60/40) along with 1 and some
byproduct.8 For the complete consumption of the unreacted 1,
the longer reaction times caused 3a to decompose and decrease
the yield by contrast. It is noteworthy that when the reaction was
conducted at an elevated temperature (50 °C), the reaction was
complicated to afford none of 3a. These unfortunate observa-
tions compelled us to continue examinations of a wide range of
reaction factors such as Pd catalyst, a base, a solvent, temperature,
and an additive.
Received: August 18, 2011
Published: September 29, 2011
r
2011 American Chemical Society
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|

The Journal of Organic Chemistry
NOTE
Table 1. Optimization of Reaction Conditions for the MizorokiꢀHeck Reaction of 1a
entry
Pd (10 mol %)
base (equiv)
solvent
temp/°C
time/h
additive
yieldb/%
E/Zc
1
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
PdCl2
Ag2CO3 (3)
NaOAc (3)
TEA (3)
DMF
25
50
2
12
12
10
12
12
12
10
12
12
12
10
12
12
12
20
10
none
25
trace
0
60/40
2
DMF
none
3
DMF
100
50
none
4
Ag2CO3 (3)
Ag2CO3 (3)
Ag2CO3 (3)
Ag2CO3 (3)
Ag2CO3 (3)
Ag2CO3 (3)
Ag2CO3 (3)
Ag2CO3 (3)
Ag2CO3 (4)
Ag2CO3 (3)
Ag2CO3 (2)
Ag2CO3 (1)
Ag2CO3 (3)
Ag2CO3 (3)
DMF
none
0
5
Pd(PPh3)4
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
DMF
50
none
0
6
DMSO
NMP
100
100
100
50
none
0
7
none
0
8
DMI
none
0
9
MeCN
THF
none
0
10
11
12
13
14
15
16d
17
60
none
0
dioxane
dioxane
dioxane
dioxane
dioxane
dioxane
dioxane
90
none
40
72
72
62
48
60
56
98/2
98/2
98/2
98/2
98/2
97/3
99/1
90
MS 4 Å
MS 4 Å
MS 4 Å
MS 4 Å
MS 4 Å
MS 4 Å
90
90
90
90
70
a The reactions were carried out in a 0.2 mmol scale with 1 mL of a solvent. b Isolated yield. c Determined by GCꢀMS. d Pd(OAc)2 (5 mol %) was used.
Scheme 1
Table 2. Scope of Aryl Iodidesa
entry
ArI
4-AcC6H4I
3
time/h
yieldb/%
E/Zc
1
2
3a
3b
3c
3d
3e
3f
4
2
72
63
81
63
77
61
70
88
85
60
65
78
67
72
98/2
99/1
96/4
93/7
97/3
97/3
98/2
97/3
98/2
98/2
98/2
97/3
98/2
96/4
4-EtOC(dO)C6H4I
4-O2NC6H4I
4-NCC6H4I
4-CF3C6H4I
4-MeOC6H4I
2-FC6H4I
3
4
To illustrate the synthetic scope of this methodology, we
briefly attempted to modify the resulting product 3f (Scheme 2).
Our choice was the stereoselective synthesis of the corre-
sponding cis-β-fluorostyrene 4f. If this transformation pro-
ceeds with complete retention of the configuration of the
double bond, an overall reaction should provide a new
stereoselective approach to cis-β-fluorostyrene derivatives.10
As expected, the fluoride ion-assisted desilylationꢀprotona-
tion smoothly proceeded giving the desired 4f; however, the
purification of 4f from the crude reaction mixture on silica gel
column chromatography proved to be more difficult due to
their very close Rf values between 4f and impurities. To
overcome this problem, the transformation was achieved by
treatment with potassium tert-butoxide (t-BuOK) in DMSO.
The sequentially successful purification of 4f on silica gel
column chromatography was performed to afford the desired
4f in 99% yield.
4
3
5
5
6
5
7
3g
3h
3i
19
4
8
2-ClC6H4I
9
2-BrC6H4I
3
10
11
12
13
14
2-MeOC(dO)C6H4I
2-EtC6H4I
3j
2
3k
3l
6
3-MeOC6H4I
2,4-Me2C6H3I
C6H5I
4
3m
18
3n
6
a The reactions were carried out in a 0.2 mmol scale with 1 mL of 1,4-
dioxane at 90 °C. b Isolated yield. c Determined by GCꢀMS.
the product smoothly proceeds giving the corresponding β-
fluorostyrene derivative with very high stereoselectivity. This
protocol should offer additional opportunities to be of help in
fluoroorganic synthesis.
In summary, we have developed the MizorokiꢀHeck reaction
of silylated fluoroolefin 1 with various aryl iodides in good to high
yields for the first time. The desilylationꢀprotonation reaction of
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dx.doi.org/10.1021/jo201720x |J. Org. Chem. 2011, 76, 8564–8568

The Journal of Organic Chemistry
NOTE
Scheme 2. Transformation of 3f
171.0 (d, J = 299.0 Hz); 19F NMR (CDCl3, 283 MHz) δ ꢀ113.6 (d, J =
49.4 Hz); GCꢀMS (EI, m/z, 70 eV) 347 (5), 286 (4), 255 (23), 231
(55), 201 (81), 178 (21), 165 (25), 139 (100), 105 (32), 91 (95). Anal.
Calcd for C21H18FNO2Si: C, 69.40; H, 4.99; N 3.85. Found: C, 69.33;
H, 4.96; N, 3.83.
(E)-[1-Fluoro-2-(40-cyanophenyl)vinyl]methyldiphenylsilane
(3d): pale yellow solid; yield 63%; mp 109.0ꢀ110.9 °C; IR (KBr) 2229,
1588, 1505, 1488, 1428, 1255, 1109, 1049, 835, 800, 783, 733, 700 cmꢀ1;1H
NMR (CDCl3, 300 MHz) δ 0.81 (3H, s), 5.93 (1H, d, J = 49.6 Hz),
7.36ꢀ7.51 (7H, m), 7.55ꢀ7.66 (7H, m); 13C NMR (CDCl3, 75 MHz)
δ ꢀ5.1, 110.9 (d, J = 3.1 Hz), 118.8, 121.3 (d, J = 1.9 Hz), 128.2, 129.6 (d,
J = 8.7 Hz), 130.3, 132.1, 132.6, 135.0, 137.6 (d, J = 3.1 Hz), 170.4 (d, J =
297.7 Hz); 19F NMR (CDCl3, 283 MHz) δ ꢀ107.0 (d, J = 49.6 Hz);
GCꢀMS (EI, m/z, 70 eV) 343 (2, M+), 280 (4), 265 (15), 250 (14), 227
(7), 201 (66), 179 (15), 139 (100), 105 (19), 91 (47); HRMS (FAB, m/z)
calcd for C22H19NFSi 344.1295, found 344.1271.
’ EXPERIMENTAL SECTION
General Information. 1H, 13C, and 19F NMR spectra were mea-
sured in CDCl3 solutions. Chemical shifts were given by δ relative to
that of an internal Me4Si (TMS) for 1H NMR and 13C NMR spectra.
Chemical shifts were given by δ relative to that of CFCl3 for 19F NMR
spectra using an internal CF3C6H5 (benzotrifluoride) or C6F6. Infrared
(IR) spectra are reported in cmꢀ1. Melting points are uncorrected.
(E)-[1-Fluoro-2-(40-acetylphenyl)vinyl]methyldiphenylsilane
(3a). A 25 mL two-necked flask equipped with a magnetic stir bar, a
stopcock, and a three-way stopcock was charged with 1 (47.5 mg,
0.196 mmol), 2a (96.4 mg, 0.391 mmol), Ag2CO3 (162.1 mg, 0.606 mmol),
Pd(OAc)2 (4.4 mg, 0.02 mmol), and powdered MS4 Å (ca. 160 mg) in
1,4-dioxane (1 mL), successively. The reaction mixture was heated at 90 °C.
When the reaction was completed for 4 h as monitored by GCꢀMS, the
reaction was cooled to room temperature. The reaction mixture was filtered
off through Celite pad with ether. After the filtrate was added with water, the
organic layer was separated. An additional extraction with hexane/EtOAc =
3/1 was repeated twice. The combined organic solution was dried over
Na2SO4 and concentrated in vacuo. The resulting oily residue was first
purified by column chromatography (silica gel, hexane/EtOAc = 10/1) to
give the desired compound 3a along with a small amount of impurities. The
resulting oily residue was additionally purified by bulb-to-bulb distillation to
give pale yellow solid (50.9 mg, 72%): mp 92.1ꢀ93.5 °C; IR (KBr) 3069,
1680, 1601, 1489, 1355, 1266, 1184, 1115, 1044, 796, 736, 701 cmꢀ1; 1H
NMR (CDCl3, 300 MHz) δ0.81 (3H, s), 2.59 (3H, s), 5.97 (1H, d, J = 50.3
Hz), 7.36ꢀ7.49 (6H, m), 7.60ꢀ7.66 (6H, m), 7.90 (2H, d, J = 8.4 Hz); 13C
NMR (CDCl3, 75 MHz) δ ꢀ5.0 (d, J = 1.2 Hz), 26.6, 122.4 (d, J = 1.9 Hz),
128.2, 128.5, 129.3 (d, J = 8.1 Hz), 130.2, 133.0 (d, J = 1.2 Hz), 135.0, 135.9
(d, J = 2.5 Hz), 137.8 (d, J = 2.5 Hz), 169.4 (d, J = 295.8 Hz), 197.5; 19F
NMR (CDCl3, 283 MHz) δ ꢀ108.6 (d, J = 50.3 Hz); GCꢀMS m/z 360
(3, M+), 344 (7), 281 (8), 266 (14), 201 (59), 181 (22), 139 (100), 105
(19), 91 (44). Anal. Calcd for C23H21FOSi: C, 76.63; H, 5.87. Found: C,
76.64; H, 5.89.
(E)-[1-Fluoro-2-[40-(trifluoromethyl)phenyl]vinyl]methyl-
diphenylsilane (3e): colorless oil; yield 77%; IR (neat) 3071, 1617,
1489, 1430, 1326, 1168, 1115, 1068, 829, 794, 728, 698, 671 cmꢀ1
;
1H NMR (CDCl3, 300 MHz) δ 0.81 (3H, s), 5.96 (1H, d, J = 50.1 Hz),
7.36ꢀ7.47 (7H, m), 7.52ꢀ7.68 (7H, m); 13C NMR (CDCl3, 75
MHz) δ ꢀ4.96, 122.0 (d, J = 1.3 Hz), 125.3 (q, J = 3.7 Hz), 124.1
(q, J = 277.2 Hz), 128.2, 129.4 (d, J = 8.1 Hz), 129.6 (d, J = 2.5 Hz),
130.0 133.1 (d, J = 1.9 Hz), 135.0, 136.6 (dq, J = 3.1, 1.3 Hz), 169.2
(d, J = 294.6 Hz); 19F NMR (CDCl3, 283 MHz) δ ꢀ64.0, ꢀ109.5 (d, J =
50.1 Hz); GCꢀMS (EI, m/z, 70 eV) 386 (1, M+), 308 (10), 293
(11), 246 (20), 227 (55), 201 (92), 151 (55), 139 (100), 105 (41), 91
(76). Anal. Calcd for C22H18F4Si: C, 68.37; H, 4.69. Found: C, 68.66;
H, 4.74.
(E)-[1-Fluoro-2-(40-methoxyphenyl)vinyl]methyldiphenyl-
silane (3f): white solid; yield 61%; mp 47.1ꢀ49.0 °C; IR (KBr) 3011,
1606, 1506, 1428, 1251, 1180, 1117, 1044, 874, 829, 739, 701 cmꢀ1; 1H
NMR (CDCl3, 300 MHz) δ 0.77 (3H, s), 3.80 (3H, s), 5.87 (1H, d, J =
51.8 Hz), 6.84 (2H, d, J = 9.0 Hz), 7.34ꢀ7.46 (6H, m), 7.15 (2H, J = 8.8
Hz), 7.63 (4H, dd, J = 7.7, 1.5 Hz); 13C NMR (CDCl3, 75 MHz)
δ ꢀ4.81(d, J = 1.2 Hz), 55.2, 113.9, 123.0 (d, J = 1.3 Hz), 126.3 (d, J = 2.5
Hz), 128.0, 129.9, 130.7 (d, J = 8.1 Hz), 133.7 (d, J = 1.2 Hz), 135.0, 159.1
(d, J = 3.1 Hz), 165.2 (d, J = 286.5 Hz); 19F NMR (CDCl3, 283 MHz)
δ ꢀ117.3 (d, J = 51.8 Hz); GCꢀMS (EI, m/z, 70 eV) 348 (19, M+), 286
(5), 255 (26), 231 (57), 201 (83), 178 (20), 165 (25), 139 (100), 105
(29), 91 (79). Anal. Calcd. for C22H21FOSi: C, 75.82; H, 6.07. Found: C,
75.82; H, 6.08.
(E)-[1-Fluoro-2-[20-(fluorophenyl)vinyl]methyldiphenylsilane
(3g): colorless oil; yield 70%; IR (neat) 3071, 1579, 1482, 1429, 1231,
1117, 1100, 1054, 793, 755, 727, 670 cmꢀ1; H NMR (CDCl3, 300 MHz)
δ 0.80 (3H, s), 6.31 (1H, d, J = 51.1 Hz), 6.98ꢀ7.04 (1H, m), 7.06ꢀ7.15
(1H, m), 7.17ꢀ7.25 (1H, m), 7.78ꢀ7.47 (6H, m), 7.64 (4H, dd, J = 1.8,
7.5 Hz), 7.93ꢀ8.02 (1H, m); 13C NMR (CDCl3, 75 MHz) δ ꢀ4.9,
114.4 (dd, J = 6.8, 1.8 Hz), 115.1 (d, J = 21.1 Hz), 121.1 (dd, J = 11.9, 2.5
Hz), 124.2 (d, J = 19.9 Hz), 128.1, 129.3 (dd, J = 8.7, 1.9), 130.1, 131.1
(dd, J = 13.7, 2.5 Hz) 133.2, 135.0, 159.3 (dd, J = 249.8, 1.2 Hz), 168.5
(dd, J = 293.3, 2.5 Hz); 19F NMR (CDCl3, 283 MHz) δ ꢀ117.6 (ddd,
J = 9.3, 6.1, 6.1), ꢀ111.3 (dd, J = 51.1, 6.1 Hz); GCꢀMS (EI, m/z, 70
eV) 336 (0.5, M+), 254 (49), 239 (28), 201 (86), 178 (59), 165 (28),
152 (24), 139 (100), 105 (30), 91 (76). Anal. Calcd for C21H18F2Si: C,
74.97; H, 5.39. Found: C, 75.13; H, 5.39.
(E)-[1-Fluoro-2-[40-(ethoxycarbonyl)phenyl]vinyl]methyl-
diphenylsilane (3b): white solid; yield 63%; mp 71.1ꢀ72.7 °C; IR
(KBr) 3066, 2974, 1708, 1606, 1427, 1286, 1180, 1109, 1051, 1017, 784,
734, 699 cmꢀ1; 1H NMR (CDCl3, 300 MHz) δ 0.81 (3H, s), 1.39 (3H, t,
J = 7.16 Hz), 4.37 (2H, q, J = 7.16 Hz), 5.97 (1H, d, J = 50.7 Hz),
7.37ꢀ7.51 (6H, m), 7.57ꢀ7.68 (6H, m), 7.98 (2H, d, J = 8.3 Hz); 13C
NMR (CDCl3, 75 MHz) δ ꢀ5.0, 14.3, 60.9, 122.5 (d, J = 1.8 Hz), 129.1
(d, J = 8.1 Hz), 129.3 (d, J = 2.5 Hz), 129.6, 130.2, 133.0, 135.0, 137.5 (d,
J = 2.5 Hz), 166.3, 169.1 (d, J = 295.2 Hz); 19F NMR (CDCl3, 283 MHz)
δ ꢀ109.2 (d, J = 50.7 Hz); GCꢀMS (EI, m/z, 70 eV) 348 (21), 286 (5),
255 (26), 231 (60), 201 (89), 169 (25), 139 (100), 105 (30), 91 (81), 77
(17). Anal. Calcd for C24H23FO2Si: C, 73.81; H, 5.94. Found: C, 74.00;
H, 6.02.
(E)-[1-Fluoro-2-[40-(nitrophenyl)vinyl]methyldiphenylsilane
(3c): pale yellow solid; yield 81%; mp 87.9ꢀ89.0 °C; IR (KBr) 3068,
1633, 1597, 1521, 1428, 1342, 1116, 1108, 1058, 824, 795, 735,
674 cmꢀ1; H NMR (CDCl3, 300 MHz) δ 0.82 (3H, s), 5.99 (1H, d, J
= 49.4 Hz), 7.37ꢀ7.53 (6H, m), 7.63 (4H, dd, J = 7.7, 1.8 Hz), 7.68 (2H,
d, J = 8.8 Hz), 8.17 (2H, d, J = 8.8 Hz); 13C NMR (CDCl3, 75 MHz) δ
ꢀ5.0, 121.3 (d, J = 1.9 Hz), 123.7, 128.2, 129.8 (d, J = 8.7 Hz), 130.3,
132.5 (d, J = 1.2 Hz), 135.0, 139.5 (d, J = 3.1 Hz), 146.6 (d, J = 3.1 Hz),
(E)-[1-Fluoro-2-(20-chlorophenyl)vinyl]methyldiphenylsilane
(3h): colorless oil; yield 88%; IR (neat) 3070, 1589, 1429, 1254, 1115, 1052,
794, 728, 698 cmꢀ1; 1H NMR(CDCl3, 300 MHz) δ0.81 (3H, s), 6.41 (1H,
d, J = 50.5 Hz), 7.13ꢀ7.27 (2H, m), 7.32ꢀ7.48 (7H, m), 7.65 (4H, dd, J =
7.3, 1.5 Hz), 7.96 (1H, dd, J = 7.7, 1.3 Hz); 13C NMR (CDCl3, 75 MHz)
δ ꢀ4.93 (d, J = 1.3 Hz), 119.1 (d, J = 2.5 Hz), 126.7, 128.1, 128.8 (d, J =
1.2 Hz), 129.4, 130.1, 131.1 (d, J = 2.5 Hz), 131.3 (d, J = 12.4 Hz), 132.7 (d,
J = 1.2 Hz), 133.2 (d, J = 1.2 Hz), 135.0, 168.2 (d, J = 294.6 Hz); 19F NMR
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NOTE
(CDCl3, 283 MHz) δ ꢀ113.3 (d, J = 50.5 Hz); GCꢀMS (EI, m/z, 70 eV)
352 (0.1, M+), 254 (21), 239 (5), 223 (5), 212 (10), 201 (53), 178 (32), 139
(100), 105 (19), 91 (50). Anal. Calcd. for C21H18ClFSi: C, 71.47; H, 5.14.
Found: C, 71.56; H, 5.13.
253 (14), 229 (7), 201 (91), 181 (16), 165 (11), 152 (7), 139 (100), 105
(38), 91 (68). Anal. Calcd for C23H23FSi: C, 79.72; H, 6.69. Found: C,
79.74; H, 6.71.
(E)-(1-Fluoro-2-phenylvinyl)methyldiphenylsilane (3n):
colorless oil; yield 72%; IR (neat) 3070, 3051, 3025, 1589, 1447, 1115,
1049, 793, 727, 695 cmꢀ1; 1H NMR (CDCl3, 300 MHz) δ 0.80 (3H, s),
5.96 (1H, d, J = 50.1 Hz), 7.35ꢀ7.47 (7H, m), 7.51ꢀ7.58 (2H, m),
7.59ꢀ7.67 (7H, m); 13C NMR (CDCl3, 75 MHz) δ ꢀ4.9 (d, J = 1.3
Hz), 123.4 (d, J = 1.9 Hz), 127.8 (d, J = 2.5 Hz), 128.1, 128.4, 129.3 (d,
J = 7.4 Hz), 130.0, 133.3 (d, J = 2.5 Hz), 133.4 (d, J = 1.3 Hz), 135.0,
166.9 (d, J = 290.2 Hz); 19F NMR (CDCl3, 283 MHz) δ ꢀ106.1 (d, J =
50.1 Hz); GCꢀMS (EI, m/z, 70 eV) 318 (2, M+), 302 (5), 255 (11), 239
(31), 225 (39), 201 (97), 178 (84), 139 (100), 105 (30), 91 (56);
HRMS (EI, m/z) calcd for C21H19FSi 318.1240, found 318.1209.
(Z)-1-Fluoro-2-(40-methoxyphenyl)ethene (4f)10a. A 25 mL
two-neck flask equipped with a magnetic stir bar, a stopcock, and a
three-way stopcock was charged with 3f (72.9 mg, 0.209 mmol), t-BuOK
(34.7 mg, 0.309 mmol), and DMSO (1.0 mL) at room temperature.
After the reaction was stirred for 1 h, the reaction mixture was quenched
with water. After separation of the organic layer, additional extraction
with hexane/EtOAc was repeated twice. The combined organic solution
was dried over Na2SO4 and concentrated in vacuo. The residual oil was
purified by silica gel chromatography (hexane/ether =100/1) to give 4f
as a colorless oil (31.6 mg, 99%): 1H NMR (CDCl3, 300 MHz) δ 3.81
(3H, s), 5.54 (1H, dd, J = 35.1, 5.3 Hz), 6.59 (1H, dd, J = 82.9, 5.3 Hz),
6.87 (2H, d, J = 8.8 Hz), 7.45 (2H, d, J = 8.8 Hz).
(E)-[1-Fluoro-2-(20-bromophenyl)vinyl]methyldiphenylsilane
(3i): colorless oil; yield 85%; IR (neat) 3070, 1589, 1461, 1429, 1254,
1115, 1057, 1045, 793, 728, 698 cmꢀ1; 1H NMR (CDCl3, 300 MHz) δ
0.81 (3H, s), 6.37 (1H, d, J = 50.1 Hz), 7.04ꢀ7.14 (1H, m), 7.23ꢀ7.32
(1H, m), 7.36ꢀ7.48 (6H, m), 7.55 (1H, dd, J = 8.1, 1.3 Hz), 7.65 (4H,
dd, J = 7.7, 1.8 Hz), 7.93 (1H, dd, J = 7.7, 1.7 Hz); 13C NMR (CDCl3,
75 MHz) δ ꢀ4.98 (d, J = 1.2 Hz), 121.9 (d, J = 3.2 Hz), 123.4 (d, J =
1.2 Hz), 127.3, 128.1, 129.0 (d, J = 1.3 Hz), 130.1, 131.4 (d, J = 20.5 Hz),
132.67, 132.73 (d, J = 12.4 Hz), 133.1 (d, J = 1.2 Hz), 135.0, 167.9 (d, J =
294.6 Hz); 19F NMR (CDCl3, 283 MHz) δ ꢀ114.0 (d, J = 50.1 Hz);
GCꢀMS (EI, m/z, 70 eV) 397 (0.8, M+), 317 (7), 302 (10), 255 (28),
239 (44), 223 (9), 201 (98), 178 (71), 139 (100), 91 (68). Anal. Calcd
for C21H18BrFSi: C, 63.48; H, 4.57. Found: C, 63.71; H, 4.58.
(E)-[1-Fluoro-2-[20-(methoxycarbonyl)phenyl]vinyl]methyl-
diphenylsilane (3j): colorless oil; yield 60%; IR (neat) 1721, 1598,
1429, 1080, 794, 728 cmꢀ1; 1H NMR (CDCl3, 300 MHz) δ 0.81 (3H, s),
3.75 (3H, s), 6.77 (1H, d, J = 50.3 Hz), 7.25ꢀ7.35 (1H, m), 7.35ꢀ7.51
(8H, m), 7.66 (4H, dd, J = 1.8, 7.5 Hz), 7.82ꢀ7.92 (1H, m); 13C NMR
(CDCl3, 75 MHz) δ ꢀ5.0 (d, J = 1.2 Hz), 51.9, 121.6 (d, J = 3.2 Hz), 123.4
(d, J = 1.2 Hz), 127.3, 128.1, 129.0 (d, J = 1.3 Hz), 130.0, 131.3 (d, J = 9.4
Hz), 131.7, 133.3 (d, J = 4.4 Hz), 133.4 (d, J = 1.3 Hz), 135.1, 166.6 (d, J =
292.1 Hz), 167.8; 19F NMR (CDCl3, 283 MHz) δ ꢀ116.4 (d, J =
50.3 Hz); GCꢀMS (EI, m/z, 70 eV) 376 (0.2, M+), 360 (4), 299 (37), 197
(64), 179 (100), 151 (37), 139 (34), 129 (41), 101 (25), 91 (42). Anal.
Calcd. for C23H21O2FSi: C, 73.37; H, 5.62. Found: C, 73.66; H, 5.76.
(E)-[1-Fluoro-2-(20-ethylphenyl)vinyl]methyldiphenylsilane
(3k): colorless solid; yield 65%; mp 46.0ꢀ48.0 °C; IR (KBr) 3068, 2965,
1588, 1476, 1428, 1250, 1118, 1044, 757, 736, 700, 670 cmꢀ1; 1H NMR
(CDCl3, 300 MHz) δ 0.80 (3H, s), 1.08 (3H, t, J = 7.52 Hz), 2.51 (2H, q,
J = 7.52 Hz), 6.12 (1H, d, J = 50.6 Hz), 7.11ꢀ7.22 (2H, m), 7.36ꢀ7.47
(7H, m), 7.64 (4H, dd, J = 2.0, 7.7 Hz), 7.75ꢀ7.84 (1H, m); 13C NMR
(CDCl3, 75MHz) δꢀ4.9, 15.0, 26.9, 121.0 (d, J=1.3Hz), 125.9, 128.0(d,
J = 1.2 Hz), 128.1, 128.6, 130.0, 130.2 (d, J = 10.0 Hz), 130.9 (d, J =
2.5 Hz), 133.6 (d, J = 1.9 Hz), 135.0, 141.8, 166.4 (d, J = 290.2 Hz); 19F
NMR (CDCl3, 283 MHz) δ ꢀ116.5 (d, J = 50.6 Hz); GCꢀMS (EI, m/z,
70 eV) 347 (11, M+), 346 (35), 253 (6), 206 (23), 201 (61), 197 (48), 191
(12), 139 (100), 129 (26), 91 (22). Anal. Calcd for C23H23FSi: C, 79.72;
H, 6.69. Found: C, 79.71; H, 6.67.
’ ASSOCIATED CONTENT
Supporting Information. 1H, 13C, and 19F NMR spectral
S
b
data. This material is available free of charge via the Internet at
http://pubs.acs.org/.
’ AUTHOR INFORMATION
Corresponding Author
*E-mail: hanamoto@cc.saga-u.ac.jp.
’ ACKNOWLEDGMENT
We greatly thank Tosoh F-Tech, Inc., for a gift of 1,1-difluoro-
ethylene and also JNC Corp. (the former Chisso Petrochemical
Corp.) for a gift of chloromethyldiphenylsilane. We thank Prof.
Junji Inanaga and Prof. Hiroshi Furuno at Kyushu University for
their valuable discussions and experimental support.
(E)-[1-Fluoro-2-(30-methoxyphenyl)vinyl]methyldiphenyl-
silane (3l): colorless oil; yield 78%; IR (neat) 1599, 1428, 1256, 1115,
1
1050, 792, 670, 727, 697 cmꢀ1; H NMR (CDCl3, 300 MHz) δ 0.79
(3H, s), 3.79 (3H, s), 5.91 (1H, d, J = 51.0 Hz), 6.98 (1H, dd, J = 2.6,
8.1 Hz), 7.07ꢀ7.27 (3H, m), 7.35ꢀ7.47 (6H, m), 7.63 (4H, dd, J = 1,8,
7.7) ppm; 13C NMR (CDCl3, 75 MHz) δ ꢀ4.9 (d, J = 1.2 Hz), 55.2,
114.0 (d, J= 1.9 Hz), 114.3 (d, J= 8.1 Hz), 121.9 (d, J= 6.9 Hz), 123.3 (d, J=
1.9 Hz), 128.1, 129.3, 130.0, 133.4 (d, J = 1.3 Hz), 134.5 (d, J = 2.4 Hz),
135.0, 159.5, 167.1 (d, J = 291.4 Hz); 19F NMR (CDCl3, 283 MHz)
δ ꢀ112.6 (d, J = 51.0 Hz); GCꢀMS (EI, m/z, 70 eV) 348 (8, M+), 332
(4), 269 (9), 254 (41), 201 (73), 178 (37), 165 (18), 139 (100), 105
(26), 91 (70). Anal. Calcd for C22H21FOSi: C, 75.82; H, 6.07. Found: C,
75.78; H, 6.08.
(E)-[1-Fluoro-2-(20,40-dimethylphenyl)vinyl]methyldiphenyl-
silane (3m): colorless oil; yield 67%; IR (neat) 3070, 1613, 1589, 1429,
1253, 1116, 1053, 793, 728, 698 cmꢀ1; 1H NMR (CDCl3, 300 MHz) δ 0.70
(3H, s), 2.15 (3H, s), 2.28 (3H, s), 6.07 (1H, d, J = 49.2 Hz), 6.94ꢀ7.01
(2H, m), 7.34ꢀ7.45 (6H, m), 7.64 (4H, dd, J = 1.7, 7.5 Hz), 7.69 (1H, d, J =
7.9 Hz); 13C NMR (CDCl3, 75 MHz) δ ꢀ4.9 (d, J = 1.2 Hz), 19.9, 21.1,
121.0, 126.6, 128.0, 128,4 (d, J = 1.8 Hz), 129.8, 130.0, 130.8, 133.7, 135.0,
135.5, 137.5 (d, J = 1.2 Hz), 165.8 (d, J = 289.0 Hz); 19F NMR (CDCl3, 283
MHz) δ ꢀ116.4 (d, J = 49.2 Hz); GCꢀMS (EI, m/z, 70 eV) 347 (3, M+),
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