Iridium-Catalyzed Intramolecular Cycloisomerization between Functionalized Alkyne with Aryl Vinyl Ether: Synthesis of 2-Vinyl-3-functionalized Methylbenzofurans

Article abstract of DOI:10.1021/acs.joc.0c00954

We have developed cycloisomerization between an aryl vinyl ether and a functionalized alkyne, such as silylalkyne, to give 2,3-disubstituted benzofuran derivatives using [IrCl(cod)]2, PCy3, and NaBArF4. This catalyst system not only catalyzes the above cycloisomerization but also isomerize a terminal olefin to give an aryl vinyl ether.

Full text of DOI:10.1021/acs.joc.0c00954

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Note
Iridium-Catalyzed Intramolecular Cycloisomerization
between Functionalized Alkyne with Aryl Vinyl Ether:
Synthesis of 2-Vinyl-3-Functionalized Methyl-Benzofurans
Jiawei Qiu, Shohei Ohno, Tsuyoshi Matsuzaki, Takeyuki Suzuki, Kenichi Murai, and Mitsuhiro Arisawa
J. Org. Chem., Just Accepted Manuscript • DOI: 10.1021/acs.joc.0c00954 • Publication Date (Web): 24 Jun 2020
Downloaded from pubs.acs.org on June 24, 2020
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Iridium-Catalyzed Intramolecular Cycloisomerization between Functionalized Alkyne with
Aryl Vinyl Ether: Synthesis of 2-Vinyl-3-Functionalized Methyl-Benzofurans
Jiawei Qiu, Shohei Ohno, Tsuyoshi Matsuzaki, Takeyuki Suzuki, Kenichi Murai, Mitsuhiro
Arisawa*
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Graduate School of Pharmaceutical Sciences, Osaka University, Yamada-oka 1-6, Suita, Osaka 565-
0
871, Japan,
Comprehensive Analysis Center, The Institute of Scientific and Industrial Research, Osaka University, Mihogaoka
-1, Ibaraki, Osaka 567-0047, Japan
8
arisaw@phs.osaka-u.ac.jp
Abstract: We have developed cycloisomerization between aryl vinyl ether and functionalized
alkyne, such as silylalkyne, to give 2,3-disubstituted benzofuran derivatives, using [IrCl(cod)]
2
, PCy
3
and NaBArF
. This catalyst system not only catalyzes the above cycloisomerization but also
4
isomerize a terminal olefin to give an aryl vinyl ether.
Keywords
cycloisomerization, iridium, benzofuran
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Previous work
1
2 cat. system
. RuHCl(CO)(PPh ) (5 mol%)
3 3
CH Cl , reflux
2
2
2
. Grubbs II (10 mol%)
CH =CHOSiMe (1 eq.)
2
3
p-xylene, reflux
SiR3
0
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0
SiR3
1. RuHCl(CO)(PPh ) 2 cat. system
3
3
CH Cl , reflux
2
2
2. [IrCl(cod)] (1.5 mol%), PCy
2
3
O
O
F
NaBAr , (CH Cl) , r.t.
R'
R'
4
2
2
[IrCl(cod)] (10 mol%), PCy
2
3
F
NaBAr , (CH Cl) , 79 °C
4
2
2
R = Me, Ph, t-Bu
R' = H, OMe, Cl, Me
This work
1
cat. system
Scheme 1. Previous Work for 2,3-Disubstituted Benzofurans Syntheses and This Work
Among transition-metal-catalyzed cycloisomerizations of 1,n-enynes, the 1,6-enyne
cycloisomerization is becoming an important class of reactions to form cyclic structures. Cyclic
structures resulting from relatively simple acyclic subunits are of interest to researchers. In these 1,6-
enyne cycloisomerizations, transition metal catalysts (such as Pd, Ru, Rh, Au) are used to yield a
1
wide array of cyclic products. However, the substrates used in these reactions usually include an
alkene and an alkyne which has hydrogen or carbon, and further chemical transformations of
products are rather difficult. In this research background, we recently reported a ruthenium catalyzed
2
cycloisomerization to give 2,3-disubstituted benzofurans , which have both a silyl group and olefin
substituents (Scheme 1 yellow zone). Although these reactions are an efficient way to prepare
heterocycles, we wondered whether there is an alternative metal catalyst system, besides ruthenium
hydride with a nitrogen-containing heterocyclic carbene ligand, for this cycloisomerization.
Here, we report an unprecedented iridium-catalyzed cycloisomerization of aryl vinyl ethers and
silylalkynes to yield 2,3-disubstituted benzofurans having useful functional groups, vinyl and
trimethylsilylmethyl, on the 2- and 3-positions, respectively (Scheme 1, green zone). We have also
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detected an iridacycle intermediate which affords benzofuran on cycloisomerization. Benzofurans
are present in numerous bioactive natural products as well as pharmaceuticals and polymers.3
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Table 1 Optimization of Cycloisomerization.
yield (%,
entry
catalyst
ligand
PCy
additive
solvent (mM)
temp. (℃)
2
steps)
13
9
1
2
[IrCl(cod)]
[IrCl(cod)]
[IrCl(cod)]
[IrCl(cod)]
[IrCl(cod)]
[IrCl(cod)]
[IrCl(cod)]
[IrCl(cod)]
[IrCl(cod)]
[IrCl(cod)]
[IrCl(cod)]
[IrCl(cod)]
[IrCl(cod)]
[IrCl(cod)]
[IrCl(cod)]
[IrCl(cod)]
[IrCl(cod)]
[IrCl(cod)]
[IrCl(cod)]
[IrCl(cod)]
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
3
-
(CH
(CH
(CH
(CH
(CH
(CH
(CH
(CH
(CH
2
2
2
2
2
2
2
2
2
Cl)
Cl)
Cl)
Cl)
Cl)
Cl)
Cl)
Cl)
Cl)
2
2
2
2
2
2
2
2
2
(100)
(100)
(100)
(100)
(100)
(100)
(100)
(100)
(100)
reflux
reflux
reflux
reflux
reflux
reflux
reflux
reflux
reflux
reflux
reflux
reflux
r.t.
P(t-Bu)
L1
3
-
3
-
trace
0
4
L2
-
-
5
L3
0
6
PCy
PCy
PCy
PCy
PCy
PCy
PCy
PCy
PCy
PCy
PCy
PCy
PCy
PCy
PCy
-
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
AgOTf
18
14
0
7
AgPF
6
8
Cu(OAc)
2
F
d
9
NaBAr
NaBAr
NaBAr
NaBAr
NaBAr
NaBAr
NaBAr
NaBAr
NaBAr
NaBAr
NaBAr
NaBAr
-
4
22
F
F
F
F
F
F
F
F
F
F
F
10
4
(CH
(CH
2
2
Cl)
2
(30)
(16)
(7.5)
(16)
(16)
46
59
29
72
78
49
70
0
11
4
4
4
4
4
4
4
4
4
4
Cl)
2
1
1
2
(CH
(CH
(CH
CH
2 2
Cl)
3
a
2
Cl)
2
14
2
2
Cl)
2
0
1
5
Cl
2
(16)
(16)
r.t.
16
C
6
H
5
CF
3
r.t.
1
1
7
8
1,4-dioxane (16)
r.t.
p-xylene (16)
r.t.
0
b
19
0
(CH
(CH
2
Cl)
Cl)
2
(16)
(16)
r.t.
96
82
0
c
2
2
2
r.t.
2
1
Pd(OAc)
Rh(cod)
6 h. 1.5 mol% of [IrCl(cod)]
2
(PPh
3
)
2
p-xylene (100)
p-xylene (100)
F
reflux
reflux
c
22
2
BF
4
BINAP
-
0
a
b
1
2
, 3 mol% of PCy
3
and 3 mol% of NaBAr
4
were used. 1 mol% of [IrCl(cod)]
2
, 2
F
d
mol% of PCy
3
and 2 mol% of NaBAr
4
were used in 48 h. SM was completely consumed.
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We prepared 2-[(trimethylsilyl)ethynyl]phenyl vinyl ether (3a) (Table 1) quantitatively by the
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isomerization of the corresponding allyl ether compound 1a and tried a variety of reaction
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conditions using transition metal catalysts and ligands. As a result, we found that when a solution of
3a, {[IrCl(cod)]
2
} (5 mol%), and ligands, PCy
3
, P(t-Bu) or L1, in dichloroethane (100 mM) was
3
refluxed for 12 hours, the expected 2,3-disubstituted benzofuran 2a was obtained in 13%, 9%, and
4
trace yields, respectively (2 steps) (entries 1, 2, and 3). The same reaction using other ligands, L2 or
L3, didn’t proceed (entries 4 and 5). Then, because some metal salt additives are known to activate
iridium catalysts and accelerate iridium catalyzed reactions, we chose to add some metal salt
additives (NaBArF
,5 AgPF
, AgOTf, and Cu(OAc)
6
7
8) to the reactions using [IrCl(cod)]
and PCy
4
6
2
2
3
(entries 6, 7, 8, and 9). As a result, in the same reaction using NaBArF
as an additive, the yield of 2a
4
was slightly increased to 22% (entry 9), which was the best among these entries. Then, we examined
the effects of concentration (entries 9 - 12), temperature (entries 11, 13, and 14), solvents (entries 13,
1
5-18), and the amount of Ir catalyst (entries 13, 19 and 20). In the beginning, we examined the
effects of concentration (entries 9 - 12) by performing the same reactions of entry 9 under different
concentrations, 100, 30, 16, 7.5 mM. From the results, it became clear that the best concentration
was 16 mM, and 2a was obtained in 59% yield (entry 11). We considered highly diluted reaction
concentrations, 16 mM, and the intramolecular reaction efficiently proceeded to give 2a. Then, we
examined the effect of reaction temperatures (entries 11, 13, and 14). As a result, 2a was obtained in
7
2% and 78% yields at room temperature and 0 °C, respectively (entries 13 and 14). We observed
that the decomposition of products was inhibited at lower temperature. Next, we examined effect of
solvent, using α,α,α,-trifluorotoluene, dichloromethane, chloroform, 1,4—dioxane, and p-xylene.
From the results, we found that dichloromethane is the best solvent among them (entries 13, 15-18).
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Finally, we examined the effect of catalyst loading (10 mol%, 1.5 mol%, and 1 mol%) in this
reaction and found that the starting material disappeared within 12 hours when iridium catalyst
loadings were 10 or 1.5 mol% and in entry 18 (iridium catalyst, 1.5 mol%) 1a was converted to 2a in
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6% yield. When the catalyst loading was decreased to 1 mol%, 82% of benzofuran and 8% of
substrate were obtained, respectively, after 48 hours. From these results, we knew that the lower
catalyst loading, 1.5 mol%, could increase yield of the product. We also confirmed that other metal
catalyst systems (Pd or Rh)9,10 did not work very well (entries 21 and 22).
Based on these results, we next examined the effect of alkyne substituents (Table 2). Trialkylsilyl
derivatives 1b–1d (SiMe
2
Bn, SiMe
2
Ph, and SiMe t-Bu) gave the corresponding cyclized products in
2
9
6%, 88%, and 45% yields, respectively; the yield difference is most likely the result of steric effects.
Derivatives with weak electron-withdrawing groups on the alkyne, i.e., t-butyl derivative 1e and
phenyl derivative 1f, did not take part in this reaction very well; 1e and 1f were converted to 2e and 2f
in 45%, 41% yields, respectively. To know the further substituent effect on alkyne, we also tried the
same reaction using the substrate with CO
2
Me or CH(OMe) and, as the results, we observed only
2
trace amount of benzofuran derivatives. It should be noted that this Ir-catalyzed methodology gave the
corresponding 2 in higher chemical yields than the previously reported Ru-catalyzed methodology2
(for example, 2b, 96% vs 78%; 2c, 88% vs 76%; 2f, 41% vs 0%).
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Table 2. Effect of Substituents on Alkyne.
R
R
1) RuHCl(CO)(PPh ) (5 mol%)
3
3
CH Cl , reflux, 1 h
2
2
2
) [IrCl(cod)] (1.5 mol%)
2
O
O
PCy (3 mol%)
3
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
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7
8
9
0
F
NaBAr (3 mol%)
4
(
CH Cl) (16 mM), r.t., time
1a - f
2 2
2a - f
entry
substrate 1
time (h)
Yield of 2
(
%, 2 steps)
R
1
2
3
1a
SiMe
3
12
8
96 (2a)
96 (2b)
88 (2c)
45 (2d)
45 (2e)
41 (2f)
1b
1c
1d
1e
1f
SiMe
SiMe
SiMe
2
Bn
2
Ph
19
24
19
7
a
4
2
t-Bu
b
5
t-Bu
c
6
Ph
a
b
c
The reaction was performed at r.t. for 15 h and at 50 °C for 4 h. 10 mol% of Ir catalyst was employed. 10
mol% of Ir catalyst was employed under refluxing conditions.
The effect of substituents on the benzene ring is summarized in Table 3. Substrates 1g–q were
subjected to the reaction conditions as shown in Table 1, entry 19. The corresponding products 2g-l
and 2n were obtained in high or moderate yields (2 steps) by this cycloisomerization (entries 2, 3, 4,
5
, 6, 7, and 9). However, only 1m, having methoxy group at 5-position, was converted to 2m in 35%
yield (entry 8). There was a sharp contrast between entry 8 and other entries. It looks like product 2m
was not stable and decomposed when it co-existed with the iridium catalyst system. Also, the
substrates which had substituents at 3-position needed more time to be converted into the target
benzofuran derivatives (entries 2 and 6). From the results of Table 3, we know that this methodology
2
gives 2 in higher chemical yields than the previously reported Ru-catalyzed method (especially, 1h,
6
1% vs 45%; 1l, 80% vs 61%).
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Table 3. Effect of Substituents on Benzene Ring.
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
SiMe3
SiMe3
3
1) RuHCl(CO)(PPh3)3 (5 mol%)
CH Cl , reflux, 1 h
3
4
5
4
5
2
2
2
) [IrCl(cod)] (1.5 mol%)
2
O
O
R
PCy (3 mol%)
R 6
6
3
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
F
NaBAr (3 mol%)
4
(
CH Cl) (16 mM), r.t., time
2 2
1
a, g - n
2a, g - n
time (h)
entry
1
substrate 1
Yield of 2
(%, 2 steps)
96 (2a)
61 (2g)
71 (2h)
82 (2i)
R
1a
1g
1h
1i
H
12
36
16
11
10
18
20
17
9
a
2
3-Cl
3
4
5
6
4-Cl
5-Cl
1j
6-Cl
86 (2j)
1k
1l
3-OMe
4- OMe
5- OMe
6- OMe
4- Me
80 (2k)
78 (2l)
a
7
8
9
1m
1n
1o
35 (2m)
96 (2n)
76 (2o)
66 (2p)
76 (2q)
b
10
13
12
12
b
1
1
1p
1q
2
4- CO Me
b
1
2
4- Br
a
b
3
mol % of Ir catalyst was employed in the second step. 10 mol% of Ru catalyst was employed in the first step.
We also examined substituent effect on alkene of 3, using 3r and 3s (Figure 1), and found that the
cycloisomerization of 3r or 3s did not proceed at all under the optimal reaction conditions, which
means methyl substituent on alkene is important in this cycloisomerization.
Next, we used ESI mass spectroscopy to obtain information about the key intermediate in this
cycloisomerization. We analyzed the reaction mixture in Table 1, entry 18. As a result, we detected a
peak of C32
H49OIrPSi at 701.2916 (see SI file, Figure S1), which corresponds to the iridacycle
11
intermediate as shown in Figure 2. We also observed Ir-H species at -13.2 ppm in the 1H-NMR
1
2
spectra of the reaction mixture using (CD
2
Cl
2
)
2
(see SI file, Figure S2). These results and control
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1
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1
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1
1
1
1
2
2
2
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2
2
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2
3
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4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
experiments results, as shown in Table 3, suggest that this cycloisomerization proceeds via a cationic
iridium species, and a plausible reaction mechanism is drawn in Scheme 2. Based on these mechanistic
considerations, we wondered if our Ir catalyst could catalyze both isomerization of the terminal olefin
of 1 to give aryl vinyl ether 3 and the subsequent cycloisomerization to afford 2. In fact, we
successfully synthesized 2a from 1a using just the Ir catalyst system in 71% yield (Scheme 3).
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
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2
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0
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2
3
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1
2
3
4
5
6
7
8
9
0
SiMe3
SiMe3
CO Me
2
O
O
3
r
3s
Figure 1. Structure of 3r and 3s.
H C CH
3
3
H C Si
3
P
Ir
CH3
O
Figure 2. Structure of Reaction Intermediate Detected by Orbitrap MS.
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SiMe3
SiMe3
O
O
+
PCy3
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
"Ir"=
SiMe3
Ir
Ir
"
Ir"
Aromatization
SiMe3
PCy3
F -
BAr
4
O
Oxidative Cyclization
O
'
'Ir''
Reductive
Elimination
SiMe3
SiMe3
Ir
Ir
H
O
O
β-H Elimination
Scheme 2. Plausible Reaction Mechanism.
[
IrCl(cod)] (10 mol%)
2
PCy (20 mol%)
NaBAr (20 mol%)
B
B
3
F
A
A
4
(
CH Cl) (16 mM)
2
2
7
9 °C
O
O
1a: A = H, B = SiMe3
2a: 71%, 8 h
51%, 19 ha)
2d: 40%, 10 h
2l: 66%, 14 h
2p: 45%, 19 h
1d: A = H, B = SiMe t-Bu
1l: A = OMe, B = SiMe3
2
1p: A = CO Me, B = SiMe
2
3
1q: A = Br, B = SiMe3
2
q: 69%, 11 h
a)
F
[
IrCl(cod)] (3 mol%), PCy (6 mol%), NaBAr (6 mol%), Benzotrifluoride (0.1 M), 95 °C.
2 3 4
Scheme 3. One-Pot Reaction of Aryl Allyl Ether and Silylalkyne Using One Catalyst System.
In conclusion, for the first time to our knowledge, we developed a iridium-catalyzed
cycloisomerization of 1, having trialkylsilylalkyne and arylvinyl ether moieties, to give 2,3-
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1
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2
2
2
2
2
2
2
2
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3
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disubstituted benzofurans 2, having vinyl and trialkylsilylmethyl groups on the 2- and 3-positions,
respectively. We also succeed in obtaining 2 from 1 by just using one Ir catalyst system, although the
previously reported Ru catalyst system required 2 kinds of Ru catalysts.
0
1
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0
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Experimental Section
General Information
was purchased from Fujifilm Wako Pure Chemical Co. as 97% purity. NaBArF
was
[
IrCl(cod)]
2
4
purchased from Ark Pharm Inc. as 97% purity. Chemicals and solvents were either purchased from
commercial suppliers or purified by standard techniques. All reactions were performed under N
2
atmosphere unless otherwise noted. For the reactions that require heating, we used oil bath apparatus.
For thin-layer chromatography (TLC), silica gel plates Merck 60 F254. 1H NMR were recorded at 300
13
MHz, 400 MHz and 500 MHz. C NMR spectra were recorded at 100 MHz and 125 MHz. Chemical
shifts are given in ppm relative to tetramethylsilane (TMS) and the coupling constants J are given in
Hz. The spectra were recorded in CDCl
3
as solvent at room temperature unless otherwise noted. TMS
1
served as internal standard (δ = 0 ppm) for H NMR, CDCl
3
was used as internal standard (δ = 77.0
1
3
ppm) for C NMR. Column chromatography was performed with silica gel 60N (spherical, neutral,
6
3-210 µm, Kanto Chemical Co., Inc.), flash silica gel 60 (spherical, acid, 40-50 µm, Kanto Chemical
Co., Inc.) and flash silica gel 60N (spherical, neutral, 40-50 µm, Kanto Chemical Co., Inc.) unless
otherwise noted. Melting points were determined at heated plate and are uncorrected. HRMS (m/z)
were measured using MALDI (Matrix Assisted Laser Desorption/Ionization)-TOF techniques unless
otherwise noted. 1a-1c, 1e-1o, 2a-2c, and 2e, 2g -2o are known compounds. 2
Preparation of O-allyl-2-[(dimethyl-t-butylsilyl)ethynyl]phenol (1d).
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To a flame dried round-bottom flask containing 2-iodophenol (1.10 g, 4.54
mmol) and (t-butyldimethylsilyl)acetylene (1.60 g, 11.4 mmol) and
triethylamine (1.90 mL, 13.6 mmol) in acetonitrile (30.0 mL) under nitrogen
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
was added copper(I) iodide (21.6 mg, 0.11 mmol) and bis(triphenylphosphine) palladium(II)
dichloride (79.7 mg, 0.11 mmol). The mixture was warmed to 50 °C and stirred for 4 h. The mixture
was diluted with ethyl acetate and the organic layer was washed with water and brine, dried over
Na
To a stirred solution of the above obtained crude 2-(t-butyldimethylsilyl)ethynylphenol in DMF (10.0
mL) were added K CO (1.30 g, 9.09 mmol) and allyl bromide (1.10 g, 9.09 mmol). The mixture was
stirred at 50 ℃ for 6 h. The mixture was diluted with n-hexane/AcOEt = 4:1 and washed with water
and brine. The combined organic layer was dried over Na SO , filtered, and concentrated. The residue
2
SO
4
, filtered, and concentrated to give 2-(t-butyldimethylsilyl)ethynylphenol.
2
3
2
4
was purified by flash column chromatography on silica gel (n-hexane/AcOEt = 40:1) to give O-allyl-
2-[(dimethyl-t-butylsilyl)ethynyl]phenol (1d) (793 mg, 79 %). Colorless needle (from n-hexane); m.p.:
1
4
6-48 ℃; H NMR (500 MHz, CDCl
3
) δ: 7.43 (dd, J = 7.5, 1.7 Hz, 1H), 7.25 – 7.22 (m, 1H), 6.88
(ddd, J = 7.5, 1.1, 1.0 Hz, 1H), 6.84 (d, J = 8.3 Hz, 1H), 6.06 (ddt, J = 17.2, 10.6, 4.9 Hz, 1H), 5.50
ddt, J = 17.2, 1.7,1.6 Hz, 1H), 5.27 (ddt, J = 10.6, 1.7, 1.6 Hz, 1H), 4.58 (ddd, J = 4.9, 1.7, 1.6 Hz,
(
13
1
2H), 1.00 (s, 9H), 0.18 (s, 6H); C{ H} NMR (100 MHz, CDCl
3
) δ: 159.7, 134.0, 133.1, 129.8, 120.6,
+
1
17.2, 113.2, 112.4, 101.9, 97.0, 69.3, 26.3, 16.9, -4.5. HRMS (APCI) m/z: [M+H] Calcd for
C H25OSi 273.1675; Found 273.1669.
17
Preparation of O-allyl-4- methoxycarbonyl-2-[(trimethylsilyl)ethynyl]phenol (1p).
To a flame dried round-bottom flask containing methyl 3-Iodo-4-methoxybenzoate (500 mg, 1.80
mmol) and trimethylsilylacetylene (354 mg, 3.60 mmol) and diisopropylamine (9.00 mL, 35.6 mmol)
in THF (9.00 mL) under nitrogen was added copper(I) iodide (17.8 mg, 0.09 mmol) and
1
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1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
bis(triphenylphosphine) palladium(II) dichloride (31.8 mg, 0.05 mmol). The mixture was warmed to
0 °C in oil bath and stirred for 3 h. The mixture was diluted with ethyl acetate and the organic layer
was washed with water and brine, dried over Na SO , filtered, and concentrated. After flash column
chromatography on silica gel (n-hexane/AcOEt 5:1) 4-methoxycarbonyl-2-
(trimethylsilyl)ethynylphenol (366 mg, 82 %) was obtained.
To a stirred solution of the above obtained 4-methoxycarbonyl-2-(trimethylsilyl)ethynylphenol (366
mg, 1.47 mmol) in DMF (3.00 mL) were added K CO (407 mg, 2.94 mmol) and allyl bromide (1.54
5
2
4
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
=
2
3
g, 11.8 mmol). The mixture was stirred at 50 ℃ in oil bath for 8 h. The mixture was diluted with n-
hexane/AcOEt = 4:1 and washed with water and brine. The combined organic layer was dried over
Na
2
SO , filtered, and concentrated. The residue was purified by flash column chromatography on silica
4
gel (n-hexane/AcOEt = 6:1) to give O-allyl-4-methoxycarbonyl-2-(trimethylsilyl)ethynylphenol (1p)
1
(
408 mg, 97 %). Colorless oil.; H NMR (500 MHz, CDCl
3
) δ: 8.13 (d, J = 2.3 Hz, 1H), 7.95 (dd, J =
8.7, 2.3 Hz, 1H), 6.86 (d, J = 8.7 Hz, 1H), 6.06 (ddt, J = 17.3, 10.6, 4.6 Hz, 1H), 5.55 (ddt, J = 17.3,
1
.7 Hz, 1H), 5.32 (ddt, J = 10.6, 1.7 Hz, 1H), 4.65 (dt, J = 4.6, 1.7 Hz, 2H), 3.88 (s, 3H), 0.26 (s, 9H);
1
3
1
C{ H} NMR (125 MHz, CDCl
3
) δ: 166.3, 162.9, 135.7, 132.2, 131.8, 122.7, 117.5, 113.1, 111.6,
+
1
00.1, 99.6, 69.2, 52.1, 0.0. HRMS (MALDI-TOF) m/z: [M+H] Calcd for C16
H
21
3
O Si 289.1251;
Found 289.1254.
Preparation of O-allyl-4-bromo-2-[(trimethylsilyl)ethynyl]phenol (1q).
To a flame dried round-bottom flask containing 4-bromo-2-iodophenol (500 mg, 1.67 mmol) and
trimethylsilylacetylene (348 mg, 3.35 mmol) and diisopropylamine (9.00 mL, 63.8 mmol) in THF
(9.00 mL) under nitrogen was added copper(I) iodide (15.7 mg, 0.08 mmol) and
bis(triphenylphosphine) palladium(II) dichloride (29.8 mg, 0.42 mmol). The mixture was warmed to
50 °C in oil bath and stirred for 4 h. The mixture was diluted with ethyl acetate and the organic layer
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6
was washed with water and brine, dried over Na
SO , filtered, and concentrated. The residue was
2
4
purified by flash column chromatography on silica gel (n-hexane/AcOEt = 10:1) to give 4-bromo-2-
((trimethylsilyl)ethynyl)phenol (442 mg, 99%).
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1
2
3
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To a stirred solution of the above obtained 4-bromo-2-((trimethylsilyl)ethynyl)phenol (442 mg, 1.64
mmol) in DMF (3.20 mL) were added K
2
CO (455 mg, 3.29 mmol) and allyl bromide (1.68 g, 13.1
3
mmol). The mixture was stirred at 77 ℃ in oil bath for 4 h. The mixture was diluted with n-
hexane/AcOEt = 4:1 and washed with water and brine. The combined organic layer was dried over
Na
2
SO , filtered, and concentrated. The residue was purified by flash column chromatography on silica
4
gel (n-hexane/AcOEt = 40:1) to give O-allyl-4-bromo-2-[(trimethylsilyl)ethynyl]phenol (1q) (470 mg,
1
9
3 %). Colorless oil. H NMR (400 MHz, CDCl
3
) δ: 7.54 (d, J = 2.5 Hz, 1H), 7.33 (dd, J = 8.8, 2.5
Hz, 1H), 6.71 (d, J = 8.8 Hz, 1H), 6.04 (ddt, J = 17.3, 10.6, 4.7 Hz, 1H), 5.52 (ddt, J = 17.3, 1.7 Hz,
13
1
1
H), 5.30 (ddt, J = 10.6, 1.7 Hz, 1H), 4.56 (dt, J = 4.7, 1.7 Hz, 2H), 0.25 (s, 9H); C{ H} NMR (100
MHz, CDCl
3
) δ: 158.7, 136.2, 132.6, 132.5, 117.3, 115.1, 114.1, 112.5, 100.3, 99.6, 69.4, 0.0. HRMS
+
(
APCI) m/z: [M+H] Calcd for C14
H18BrOSi 309.0310; Found 309.0304.
Typical procedure A: Preparation of 3-[(trialkylsilyl)methyl]-2-vinyl-1-benzofuran (2).
To a stirred solution of O-allyl-2-[(trialkylsilyl)ethynyl]phenol (1.0 eq.) in CH Cl was added
RuHCl(CO)(PPh (5 mol%) under an Ar atmosphere and the mixture was refluxed for 1-4 h. After
2
2
)
3 3
the removal of the solvent, the residue was purified by column chromatography on silica pad to remove
highly polar organometallic compounds and concentrated. To a solution of the above obtained Phenyl
enol ether derivative in degassed (CH
0 mol%) and NaBArF
(2-20 mol%) under an Ar atomosphere. The mixture was performed at one
temperature for 7-36 h and concentrated in vacuo to remove the solvent, and the obtained residue was
2
Cl)
2
(0.016 M) was added [IrCl(cod)]
2
(1-10 mol%), PCy (2-
3
2
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purified by flash column chromatography on silica gel to give 3-[(trialkylsilyl)methyl]-2-vinyl-1-
benzofuran (2).
• Preparation of 2a –o
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•
Preparation of 3-[(trimethylsilyl)methyl]-2-vinyl-1-benzofuran (2a).
Following the typical procedure A, O-allyl-2-[(trimethylsilyl)ethynyl]phenol (1a)
(
35.5 mg, 0.154 mmol) was converted to 3-[(trimethylsilyl)methyl]-2-vinyl-1-
benzofuran (2a) 2 (34.1 mg, 96%) after flash column chromatography on silica gel (n-hexane).
1
Colorless oil.; H NMR (500 MHz, CDCl
3
) δ: 7.39 (d, J = 8.1 Hz, 1H), 7.37 (d, J = 7.7 Hz, 1H), 7.28-
7.21 (m, 1H), 7.17 (dd, J = 7.7, 7.2 Hz, 1H), 6.60 (dd, J = 17.3, 11.3 Hz, 1H), 5.84 (dd, J = 17.3, 1.5
1
3
1
Hz, 1H), 5.27 (dd, J = 11.3, 1.5 Hz, 1H), 2.08 (s, 2H), 0.02 (s, 9H); C{ H} NMR (125 MHz, CDCl
δ: 154.1, 148.8, 130.1, 124.6, 123.6, 122.0, 119.9, 116.1, 112.9, 110.7, 13.0, -1.2.
Preparation of 3-[(dimethylbenzylsilyl)methyl]-2-vinyl-1-benzofuran (2b).
3
)
Following
the
typical
procedure
A,
O-allyl-2-
[
(dimethylbenzylsilyl)ethynyl]phenol (1b) (30.0 mg, 0.0977 mmol) was
2
converted to 3-[(dimethylbenzylsilyl)methyl]-2-vinyl-1-benzofuran (2b) (28.8 mg, 96%) after flash
1
column chromatography on silica gel (n-hexane). Colorless oil.; H NMR (500 MHz, CDCl
3
) δ: 7.39
(d, J = 8.2 Hz, 1H), 7.31 (d, J = 7.8 Hz, 1H), 7.28-7.19 (m, 3H), 7.16 (d, J = 7.3 Hz, 1H), 7.14-7.06
m, 1H), 7.00 (d, J = 8.2, 2H), 6.52 (dd, J = 17.3, 11.3 Hz, 1H), 5.83 (d, J = 17.3 Hz, 1H), 5.26 (d, J =
(
1
3
1
11.3 Hz, 1H), 2.16 (s, 2H), 2.11 (s, 2H), -0.04 (s, 6H); C{ H} NMR (125 MHz, CDCl
3
) δ: 154.1,
1
48.9, 139.5, 130.0, 128.3, 128.2, 124.7, 124.2, 123.5, 122.0, 119.8, 115.5, 113.2, 110.8, 25.8, 11.3, -
3.2.
Preparation of 3-[(dimethylphenylsilyl)methyl]-2-vinyl-1-benzofuran (2c).
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Following
the
typical
procedure
A,
O-allyl-2-
[
(dimethylphenylsilyl)ethynyl]phenol (1c) (30.0 mg, 0.103 mmol) was
2
converted to 3-[(dimethylphenylsilyl)methyl]-2-vinyl-1-benzofuran (2c)
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
(
26.4 mg, 88%) after flash column chromatography on silica gel (n-hexane). Colorless oil.; H NMR
(500 MHz, CDCl
3
) δ: 7.49 (dd, J = 7.8, 1.6 Hz, 1H), 7.40-7.30 (m, 4H), 7.39-7.32 (m, 4H), 7.22 (dd,
J = 7.5, 1.6 Hz, 2H), 7.14-7.04 (m, 1H), 6.42 (dd, J = 17.3, 11.3 Hz, 1H), 5.79 (dd, J = 17.3, 1.5 Hz,
1
3
1
1H), 5.18 (dd, J = 11.3, 1.5 Hz, 1H), 2.28 (s, 2H), 0.27 (s, 6H); C{ H} NMR (125 MHz, CDCl
3
) δ:
1
54.2, 149.1, 138.2, 133.6, 130.0, 129.3, 127.9, 124.6, 123.4, 121.9, 119.9, 115.3, 112.9, 110.7, 12.7,
-3.0.
Preparation of 3-[(dimethyl-t-butylsilyl)methyl]-2-vinyl-1-benzofuran (2d).
Following
the
typical
procedure
A,
O-allyl-2-[(dimethyl-t-
butylsilyl)ethynyl]phenol (1d) (30.0 mg, 0.110 mmol) was converted to 3-
[(dimethyl-t-butylsilyl)methyl]-2-vinyl-1-benzofuran (2d) (13.5 mg, 45%) after flash column
1
chromatography on silica gel (n-hexane). Colorless needle (from n-hexane); b.p.: 53-55 ℃; H NMR
(400 MHz, CDCl
3
) δ: 7.43 – 7.35 (m, 2H), 7.30-7.13 (m, 2H), 6.60 (dd, J = 17.3, 11.3 Hz, 1H), 5.85
(
dd, J = 17.3, 1.5 Hz, 1H), 5.28 (dd, J = 11.3, 1.5 Hz, 1H), 2.09 (s, 2H), 0.99 (s, 9H), -0.10 (s, 6H);
1
3
1
C{ H} NMR (100 MHz, CDCl
3
) δ: 154.2, 149.0, 130.3, 124.8, 123.8, 122.1, 120.1, 116.3, 113.1,
+
1
10.9, 26.6, 17.0, 8.5, -5.7. HRMS (APCI) m/z: [M+H] Calcd for C17
H
25OSi 273.1675; Found
273.1668.
Preparation of 3-[t-butylmethyl]-2-vinyl-1-benzofuran (2e).
Following the typical procedure A, O-allyl-2-[t-butylethynyl]phenol (1e) (30.0
mg, 0.139 mmol) was converted to 3-[t-butylmethyl]-2-vinyl-1-benzofuran (2e) 2
(13.5 mg, 45%) after flash column chromatography on silica gel (n-hexane/AcOEt = 30:1). Colorless
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oil.; H NMR (500 MHz, CDCl
3
) δ: 7.49 (d, J = 7.7 Hz, 1H), 7.41 (d, J = 8.1 Hz, 1H), 7.29-7.22 (m,
1
H), 7.21 – 7.15 (m, 1H), 6.68 (dd, J =17.3, 11.3, 1H), 5.94 (dd, J = 17.3, 1.5 Hz, 1H), 5.34 (dd, J =
1
3
1
11.3, 1.5 Hz, 1H), 2.60 (s, 2H), 0.98 (s, 9H).; C{ H} NMR (125 MHz, CDCl
24.6, 124.1, 122.3, 120.7, 116.0, 114.5, 110.9, 37.2, 33.4, 30.1.
Preparation of 3-[phenylmethyl]-2-vinyl-1-benzofuran (2f).
3
) δ: 154.1, 151.8, 131.0,
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
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8
9
0
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7
8
9
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8
9
0
1
Following the typical procedure A, O-allyl-2-[phenylethynyl]phenol (1f) (30.0 mg,
2
0.128 mmol) was converted to 3-[phenylmethyl]-2-vinyl-1-benzofuran (2f) (12.3 mg,
1
4
1%) after flash column chromatography on silica gel (n-hexane/AcOEt = 80:1). Colorless oil.; H
NMR (400 MHz, CDCl
3
) δ: 7.43 (d, J= 8.2 Hz, 1H), 7.35-7.16 (m, 7H), 7.16-7.07 (m, 1H), 6.75 (dd,
J = 17.3, 11.2 Hz, 1H), 5.98 (dd, J = 17.3, 1.5 Hz, 1H), 5.39 (dd, J = 11.3, 1.5 Hz, 1H), 4.08 (s, 2H).;
1
3
1
C{ H} NMR (100 MHz, CDCl
3
) δ: 154.2, 150.9, 139.3, 129.4, 128.5, 128.3, 126.3, 124.8, 123.1,
+
1
22.4, 119.9, 116.1, 115.3, 111.9, 29.4.; HRMS (MALDI-TOF) m/z: [M] Calcd for C17
H14O 234.1032;
Found 234.1039.
Preparation of 4-chloro-3-[(trimethylsilyl)methyl]-2-vinyl-1-benzofuran (2g).
Following
the
typical
procedure
A,
O-allyl-3-chloro-2-
[
(trimethylsilyl)ethynyl]phenol (1g) (30.0 mg, 0.113 mmol) was converted to 4-
2
chloro-3-[(trimethylsilyl)methyl]-2-vinyl-1-benzofuran (2g) (18.3 mg, 61%) after flash column
1
chromatography on silica gel (n-hexane). Colorless oil.; H NMR (400 MHz, CDCl
3
) δ: 7.30 (dd, J =
7.4, 1.7 Hz, 1H), 7.18-7.09 (m, 2H), 6.59 (dd, J = 17.3, 11.3 Hz, 1H), 5.86 (dd, J = 17.3, 1.5 Hz, 1H),
1
5
.32 (dd, J = 11.3, 1.4 Hz, 1H), 2.42 (s, 2H), 0.04 (s, 9H), H NMR (500 MHz, C
6
6
D ) δ: 7.05 (dd, J = 8.2,
0.8 Hz, 1H), 6.97 (dd, J = 7.9, 0.8 Hz, 1H), 6.69 (m, 1H), 6.41 (dd, J = 17.3, 11.2 Hz, 1H), 5.98 (dd, J = 17.3,
1
3
1
1
.5 Hz, 1H), 5.14 (dd, J = 11.2, 1.5 Hz, 1H), 2.32 (s, 2H), 0.00 (s, 9H).; C{ H} NMR (100 MHz, CDCl )
3
1
3
1
δ: 155.1, 149.6, 127.0, 126.7, 125.1, 123.8, 123.4, 116.4, 113.9, 109.8, 13.4, -1.2., C{ H} NMR
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(125MHz, C
D
) δ: 155.5, 150.0, 127.3, 126.9, 125.4, 124.0, 123.6, 116.6, 113.9, 110.0, 13.3, -1.3.
6
6
Preparation of 5-chloro-3-[(trimethylsilyl)methyl]-2-vinyl-1-benzofuran (2h).
Following the typical procedure A,
O-allyl-4-chloro-2-
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
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7
8
9
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1
2
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7
8
9
0
1
2
3
4
5
6
7
8
9
0
[
(trimethylsilyl)ethynyl]phenol (1h) (30.0 mg, 0.113 mmol) was converted to
2
5-chloro-3-[(trimethylsilyl)methyl]-2-vinyl-1-benzofuran (2h) (21.3 mg, 71%) after flash column
1
chromatography on silica gel (n-hexane). Colorless oil.; H NMR (400 MHz, CDCl
3
) δ: 7.35-7.27 (m,
2H), 7.19 (dd, J = 8.6, 2.1 Hz, 1H), 6.57 (dd, J = 17.4, 11.3 Hz, 1H), 5.85 (dd, J = 17.3, 1.4 Hz, 1H),
13
1
5
.31 (dd, J = 11.3, 1.5 Hz, 1H), 2.03 (s, 2H), 0.03 (s, 9H); C{ H} NMR (100 MHz, CDCl ) δ: 152.6,
3
150.3, 131.7, 127.7, 124.8, 123.5, 119.6, 115.8, 114.1, 111.9, 13.1, -1.1.
Preparation of 6-chloro-3-[(trimethylsilyl)methyl]-2-vinyl-1-benzofuran (2i).
Following
the
typical
procedure
A,
O-allyl-5-chloro-2-
[
(trimethylsilyl)ethynyl]phenol (1i) (30.0 mg, 0.113 mmol) was converted to
2
6-chloro-3-[(trimethylsilyl)methyl]-2-vinyl-1-benzofuran (2i) (24.6 mg, 82%)
1
after flash column chromatography on silica gel (n-hexane). Colorless oil.; H NMR (500 MHz, CDCl
3
)
δ: 7.39 (d, J = 1.7 Hz, 1H), 7.27 (d, J = 8.4 Hz, 1H), 7.15 (dd, J = 8.3, 1.8 Hz, 1H), 6.57 (dd, J = 17.3,
1.3 Hz, 1H), 5.83 (dd, J = 17.3, 1.4 Hz, 1H), 5.30 (dd, J = 11.3, 1.5 Hz, 1H), 2.05 (s, 2H), 0.02 (s,
1
13
1
9H,); C{ H} NMR (125 MHz, CDCl
13.7, 111.5, 13.1, -1.1.
Preparation of 7-chloro-3-[(trimethylsilyl)methyl]-2-vinyl-1-benzofuran (2j).
Following the typical procedure A,
3
) δ: 154.3, 149.7, 130.5, 129.0, 123.4, 122.9, 120.5, 116.0,
1
O-allyl-6-chloro-2-
[(trimethylsilyl)ethynyl]phenol (1j) (30.0 mg, 0.113 mmol) was converted to 7-
2
chloro-3-[(trimethylsilyl)methyl]-2-vinyl-1-benzofuran (2j) (25.8 mg, 86%) after
1
flash column chromatography on silica gel (n-hexane). Colorless oil.; H NMR (500 MHz, CDCl
3
) δ:
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7.26 (dd, J = 7.8, 1.3 Hz, 1H), 7.24 (dd, J = 7.6, 1.3 Hz, 1H), 7.10 (dd, J = 7.8, 7.6 Hz, 1H), 6.59 (dd,
J = 17.3, 11.3 Hz, 1H), 5.96 (dd, J = 17.3, 1.4 Hz, 1H), 5.35 (dd, J = 11.3, 1.4 Hz, 1H), 2.06 (s, 2H),
1
3
1
0.02 (s, 9H); C{ H} NMR (125 MHz, CDCl
16.6, 116.4, 114.4, 13.3, -1.1.
Preparation of 4-methoxy-3-[(trimethylsilyl)methyl]-2-vinyl-1-benzofuran (2k).
Following the typical procedure A, O-allyl-3-methoxy-2-
3
) δ: 149.9, 149.8, 131.9, 124.8, 123.2, 123.0, 118.5,
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
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7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
[(trimethylsilyl)ethynyl]phenol (1k) (30.0 mg, 0.115 mmol) was converted to 4-
2
methoxy-3-[(trimethylsilyl)methyl]-2-vinyl-1-benzofuran (2k) (24.0 mg, 80%) after flash column
1
chromatography on silica gel (n-hexane). Colorless oil.; H NMR (300 MHz, CDCl
3
) δ: 7.14 (dd, J =
8
.3, 8.1 Hz, 1H,), 7.01 (d, J = 8.3 Hz, 1H), 6.60 (d, J = 8.1 Hz, 1H), 6.55 (dd, J = 17.3, 11.3 Hz, 1H),
5.76 (dd, J = 17.3, 1.6 Hz, 1H), 5.21 (dd, J = 11.3, 1.6 Hz, 1H), 3.88 (s, 3H), 2.29 (s, 2H), -0.01 (s,
1
3
1
9
H); C{ H} NMR (125 MHz, CDCl
102.8, 55.1, 14.1, -1.3.
Preparation of 5-methoxy-3-[(trimethylsilyl)methyl]-2-vinyl-1-benzofuran (2l).
Following the typical procedure A, O-allyl-4-methoxy-2-
3
) δ: 155.5, 155.2, 147.5, 125.4, 123.6, 119.5, 116.6, 111.8, 104.3,
[
(trimethylsilyl)ethynyl]phenol (1l) (30.0 mg, 0.115 mmol) was converted to
2
5-methoxy-3-[(trimethylsilyl)methyl]-2-vinyl- 1-benzofuran (2l) (23.4 mg, 78%) after flash column
1
chromatography on silica gel (n-hexane). Colorless oil.; H NMR (500 MHz, CDCl
3
) δ: 7.28 (d, J =
8.7 Hz, 1H), 6.92-6.79 (m, 2H), 6.58 (dd, J = 17.3, 11.3 Hz, 1H), 5.81 (dd, J = 17.3, 1.5 Hz, 1H), 5.26
1
3
1
(
dd, J = 11.3, 1.5 Hz, 1H), 3.84 (s, 3H), 2.04 (s, 2H), 0.03 (s, 9H); C{ H} NMR (125 MHz, CDCl )
3
δ: 155.4, 149.7, 149.0, 130.5, 123.7, 116.2, 113.0, 112.8, 111.1, 102.7, 55.9, 13.1, -1.1.
Preparation of 6-methoxy-3-[(trimethylsilyl)methyl]-2-vinyl-1-benzofuran (2m).
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Following
the
typical
procedure
A,
O-allyl-5-methoxy-2-
[
(trimethylsilyl)ethynyl]phenol (1m) (30.0 mg, 0.115 mmol) was converted
to 6-methoxy-3-[(trimethylsilyl)methyl]-2-vinyl -1-benzofuran (2m) 2 (10.5 mg, 35%) after flash
9
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5
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5
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0
1
2
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4
5
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7
8
9
0
1
2
3
4
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7
8
9
0
1
2
3
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6
7
8
9
0
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7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
column chromatography on silica gel (n-hexane). Colorless oil.; H NMR (400 MHz, C
6
D ) δ: 7.11 (d,
6
J = 8.6 Hz, 1H), 6.95 (d, J = 2.2, Hz, 1H), 6.80 (dd, J = 8.6, 2.2 Hz, 1H), 6.55 (dd, J = 17.3, 11.3 Hz,
H), 5.73 (dd, J = 17.3, 1.6 Hz, 1H), 5.19 (dd, J = 11.3, 1.6 Hz, 1H), 3.85 (s, 3H), 2.04 (s, 2H), 0.02
1
1
3
1
(s, 9H); C{ H} NMR (125 MHz, C
11.4, 95.8, 55.1, 13.1, -1.3.
Preparation of 7-methoxy-3-[(trimethylsilyl)methyl]-2-vinyl-1-benzofuran (2n).
Following the typical procedure A, O-allyl-6-methoxy-2-
6
D ) δ: 159.3, 155.9, 148.8, 124.2, 123.9, 120.5, 116.4, 111.9,
6
1
[(trimethylsilyl)ethynyl]phenol (1n) (30.0 mg, 0.115 mmol) was converted to 7-
2
methoxy-3-[(trimethylsilyl)methyl]-2-vinyl-1-benzofuran (2n) (28.8 mg, 96%)
1
after flash column chromatography on silica gel (n-hexane). Colorless oil.; H NMR (500 MHz, CDCl
3
)
δ: 7.10 (dd, J = 7.9, 7.8 Hz, 1H), 6.99 (d, J = 7.8 Hz, 1H), 6.78 (d, J = 7.9 Hz, 1H), 6.59 (dd, J = 17.3,
11.3 Hz, 1H), 5.91 (dd, J = 17.3, 1.4 Hz, 1H), 5.28 (dd, J = 11.3, 1.4 Hz, 1H), 4.02 (s, 3H), 2.06 (s,
1
3
1
2
H), 0.02 (s, 9H); C{ H} NMR (75 MHz, CDCl
3
) δ: 149.1, 145.1, 143.3, 132.0, 123.5, 122.7, 116.5,
113.3, 112.6, 107.2, 56.2, 13.3, -1.1.
Preparation of 5-methyl-3-[(trimethylsilyl)methyl]-2-vinyl-1-benzofuran (2o).
Following the typical procedure B, O-allyl-4-methyl-2-[(trimethylsilyl)ethynyl]phenol (1o) (30.0 mg,
0
.12 mmol) was converted to 5-methyl-3-[(trimethylsilyl)methyl]-2-vinyl-1-benzofuran (2o) (22.8 mg,
1
77%) after flash column chromatography on silica gel (n-hexane). Colorless oil.; H NMR (400 MHz,
C
6
D
6
) δ: 7.26 (d, J = 8.3 Hz, 1H), 7.16 (m, 1H), 6.89 (d, J = 8.3 Hz, 1H), 6.49 (dd, J = 17.3, 11.2 Hz,
1H), 6.04 (dd, J = 17.3, 1.6 Hz, 1H), 5.16 (dd, J = 11.2, 1.6 Hz, 1H), 2.27 (s, 3H), 1.88 (s, 2H), -0.06
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1
3
1
(s, 9H). C{ H} NMR (100 MHz, C
12.7, 110.8, 21.4, 13.0, -1.2.
Preparation of 5-methoxycarbonyl -3-[(trimethylsilyl)methyl]-2-vinyl-1-benzofuran (2p).
6
D ) δ: 153.3, 149.6, 131.5, 130.6, 126.5, 124.1, 120.1, 116.1,
6
1
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
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1
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1
2
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0
Following the typical procedure B, O-allyl-4-methoxycarbonyl-2-[(trimethylsilyl)ethynyl]phenol (1p)
(30.0 mg, 0.10 mmol) was converted to 5- methoxycarbonyl-3-[(trimethylsilyl)methyl]-2-vinyl-1-
benzofuran (2p) (19.5 mg, 65%) after flash column chromatography on silica gel (n-hexane/AcOEt =
1
25:1). Colorless oil.; H NMR (400 MHz, C
6
6
D ) δ: 8.42 (d, J = 1.7 Hz, 1H), 8.09 (dd, J = 8.6, 1.7 Hz,
1
H), 7.18 (m, 1H), 6.38 (dd, J = 17.3, 11.3 Hz, 1H), 5.97 (dd, J = 17.3, 1.5 Hz, 1H), 5.14 (dd, J = 11.3,
1
3
1
1.5 Hz, 1H), 3.56 (s, 3H), 1.78 (s, 2H), -0.12 (s, 9H). C{ H} NMR (100 MHz, C
6
6
D ) δ: 166.9, 157.2,
1
50.5, 130.6, 127.0, 125.3, 123.6, 122.7, 116.8, 113.8, 111.0, 51.6, 12.8, -1.4. HRMS (MALDI-TOF)
+
m/z: [M] Calcd for C16
H
20
3
O Si 288.1171; Found 288.1176.
Preparation of 5-bromo-3-[(trimethylsilyl)methyl]-2-vinyl-1-benzofuran (2q).
Following the typical procedure B, O-allyl-4-bromo-2-[(trimethylsilyl)ethynyl]phenol (1q) (30.0 mg,
0
.10 mmol) was converted to 5-bromo-3-[(trimethylsilyl)methyl]-2-vinyl-1-benzofuran (2q) (22.5 mg,
75%) after flash column chromatography on silica gel (n-hexane). Colorless needle (from n-hexane);
1
b.p.: 59-61 ℃; H NMR (400 MHz, C
6
6
D ) δ; 7.50 (d, J = 2.0 Hz, 1H), 7.13 (dd, J = 8.6, 2.0 Hz, 1H),
6.92 (d, J = 8.6 Hz, 1H), 6.35 (dd, J = 17.3, 11.3 Hz, 1H), 5.95 (dd, J = 17.3, 1.5 Hz, 1H), 5.13 (dd, J
13
1
=
11.3, 1.5 Hz, 1H), 1.67 (s, 2H), -0.16 (s, 9H). C{ H} NMR (101 MHz, C
6
D
6
) δ: 153.3, 150.4, 132.5,
+
127.9, 123.6, 122.9, 115.9, 115.6, 114.0, 112.6, 12.7, -1.4. HRMS (APCI) m/z: [M+H] Calcd for
C H18OSi 309.0310; Found 309.0302.
14
Typical procedure C: One-pot synthesis of 2.
To a stirred solution of 1 (1 eq.) in (CH Cl) (16 mM) was added [IrCl(cod)]
2
2
2
(10 mol%), PCy (20
3
2
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mol%) and NaBArF
(20 mol%) in glove box and the mixture was performed at 79 ℃ in oil bath until
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8
9
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1
1
1
1
1
1
1
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2
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5
5
5
5
5
5
5
5
6
4
the substrate was totally consumed. After the removal of the solvent, the residue was purified by flash
column chromatography on silica gel to give 2.
0
1
2
3
4
5
6
7
8
9
0
1
2
3
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9
0
One-pot synthesis of 3-[(trimethylsilyl)methyl]-2-vinyl-1-benzofuran (2a).
Following the typical procedure C, O-allyl-2-[(trimethylsilyl)ethynyl]phenol (1a) (20.0 mg, 0.09
2
mmol) was converted to 3-[(trimethylsilyl)methyl]-2-vinyl-1-benzofuran (2a) (14.2 mg, 71%) after
flash column chromatography on silica gel (n-hexane).
One-pot synthesis of 3-[(dimethyl-t-butylsilyl)methyl]-2-vinyl-1-benzofuran (2d).
Following the typical procedure C, O-allyl-2-[(dimethyl-t-butylsilyl)ethynyl]phenol (1d) (30.0 mg,
0
.11 mmol) was converted to 3-[(dimethyl-t-butylsilyl)methyl]-2-vinyl-1-benzofuran (2d) (12.0 mg,
40%) after flash column chromatography on silica gel (n-hexane).
One-pot synthesis of 5-methoxy-3-[(trimethylsilyl)methyl]-2-vinyl-1-benzofuran (2l).
Following the typical procedure C, O-allyl-4-methoxy-2-[(trimethylsilyl)ethynyl]phenol (1l) (30.0 mg,
2
0
.12 mmol) was converted to 5-methoxy-3-[(trimethylsilyl)methyl]-2-vinyl-1-benzofuran (2l) (19.8
mg, 66%) after flash column chromatography on silica gel (n-hexane).
One-pot synthesis of 5-methoxycarbonyl-3-[(trimethylsilyl)methyl]-2-vinyl-1-benzofuran (2p).
Following the typical procedure C, O-allyl-4-methoxycarbonyl-2-[(trimethylsilyl)ethynyl]phenol (1p)
(
30.0 mg, 0.10 mmol) was converted to 5- methoxycarbonyl-3-[(trimethylsilyl)methyl]-2-vinyl-1-
benzofuran (2p) (13.5 mg, 45%) after flash column chromatography on silica gel (n-hexane/AcOEt =
5:1).
2
One-pot synthesis of 5-bromo-3-[(trimethylsilyl)methyl]-2-vinyl-1-benzofuran (2q).
Following the typical procedure C, O-allyl-4-bromo-2-[(trimethylsilyl)ethynyl]phenol (1q) (30.0 mg,
0.10 mmol) was converted to 5-bromo-3-[(trimethylsilyl)methyl]-2-vinyl-1-benzofuran (2q) (20.7 mg,
2
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69%) after flash column chromatography on silica gel (n-hexane).
Supporting Information Available
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The Supporting Information is available free of charge on the ACS Publications website at DOI:
xxxxxxxxx. Orbitrap MS charts of reaction mixture, NMR chart of iridium hydride and Spectral data
for all new compounds.
Acknowledgements
This work was partially supported by a Grant-in-Aid from JSPS KAKENHI for Precisely Designed
Catalysts with Customized Scaffolding (Grant No. JP 18H04260), T15K149760, and T15KT00630,
by Platform Project for Supporting Drug Discovery and Life Science Research (Basis for Supporting
Innovative Drug Discovery and Life Science Research (BINDS)) from AMED under Grant Number
JP20am0101084 and JP21am0101084, and by Cooperative Research Program of "Network Joint
Research Center for Materials and Devices" from the Ministry of Education, Culture, Sports, Science
and Technology (MEXT)
References
1
. For selected recent reviews of the transition-metal-catalyzed cycloisomerization, see: (a) Fang, G.;
Bi, X. Silver-catalysed reactions of alkynes: recent advances, Chem. Soc. Rev. 2015, 44, 8124-8173. (b)
Neff, R. K.; Frantz, D. E. Recent applications of chiral allenes in axial-to-central chirality transfer
reactions, Tetrahedron 2015, 71, 7-18; (c) Fürstner, A. From Understanding to Prediction: Gold- and
Platinum-Based π-Acid Catalysis for Target Oriented Synthesis, Acc. Chem. Res. 2014, 47, 925-938.
(d) Yamamoto, Y. Transition-Metal-Catalyzed Cycloisomerizations of α,ω-Dienes, Chem. Rev. 2012,
2
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112, 4736-4769.
2. Ohno, S.; Takamoto, K.; Fujioka, H.; Arisawa, M. Cycloisomerization between Aryl Enol Ether and
Silylalkynes under Ruthenium Hydride Catalysis: Synthesis of 2,3-Disubstituted Benzofurans, Org.
Lett. 2017, 19, 2422-2425.
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
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7
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6
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8
9
0
1
2
3
4
5
6
7
8
9
0
3
4
. Yeung, K. -S. Furans and Benzofurans, Topics in Heterocycl. Chem. 2012, 29, 47-76.
. For an example of previously reported Ir-catalyzed cycloisomerization see Stevenson, S. M.;
Newcomb, E. T.; Ferreira, E. M. C–C bond migration in the cycloisomerization of 1,6-enynes, Org. Chem.
Front. 2016, 3, 1228-1235.
5
. Biosca, M.; Pàmies, O.; Diéguez, M. Giving a Second Chance to Ir/Sulfoximine-Based Catalysts
for the Asymmetric Hydrogenation of Olefins Containing Poorly Coordinative Groups, J. Org. Chem.
2
019, 84, 8259−8266.
6
. Gao, P.; Foster, D.; Sipos, G.; Skelton, B. W.; Sobolev, A. N.; Dorta, R. Chiral NHC-Iridium
Complexes and Their Performance in Enantioselective Intramolecular Hydroamination and Ring-
Opening Amination Reactions, Organometallics 2020, 39, 556−573.
7
. (a) Hanasaka, F.; Fujita, K.; Yamaguchi, R. Organometallics 2006, 25, 4643-4647. (b) Cheng, H.;
Yang, D. Iridium-Catalyzed Asymmetric Ring-Opening of Oxabenzonorbornadienes with Phenols, J.
Org. Chem. 2012, 77, 9756−9765.
8
. Li, S.; Wu, L.; Qin, L.; Zhu, Y.; Su, F.; Xu, Y.; Dong, L. Iridium(III)-Catalyzed Tandem [3 + 2]
Annulation: Synthesis of Spirocyclic Phosphoramide Derivatives, Org. Lett. 2016, 18, 4214−4217.
. Steinig, A. G.; Meijere, A. D. Palladium-catalyzed polycyclization of dienynes: surprisingly facile
formation of tetracyclic systems containing a three-membered ring, Eur. J. Org. Chem. 1999,1333-
9
1
344.
1
0. Sakiyama, N.; Noguchi, K.; Tanaka, K. Rhodium-Catalyzed Intramolecular Cyclization of
2
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Naphthol- or Phenol-Linked 1,6-Enynes Through the Cleavage and Formation of sp C-O Bonds,
Angew. Chem. Int. Ed. 2012, 51, 5976-5980.
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11. We performed experiments using 50 mol% of Ir catalyst. In H NMR we could not identify other
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synthetic intermediates. See Figure S3 in SI file.
12. Brereton, K. R.; Jadrich, C. N.; Stratakes, B. M.; Miller, A. J. M. Mechanistic Basis for Tuning
Iridium Hydride Photochemistry from H Evolution to Hydride Transfer Hydrodechlorination,
2
Organometallics 2019, 38, 3104-3110.
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F
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. RuHCl(CO)(PPh ) 2. [IrCl(cod)] , PCy , NaBAr
3
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2 cat. system
SiR3
SiR3
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O
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[IrCl(cod)] , PCy , NaBAr
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R = Me, Ph, t-Bu
R' = H, OMe, Cl, Me
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