Syntheses of 2,2′-bibenzo[7]annulenes by double Au-catalyzed sequential activation of propargylic carboxylates

Article abstract of DOI:10.1016/j.tet.2016.07.060

We previously reported a novel Au-catalyzed sequential activation of two different propargyl carboxylates to 6-methylene-6H-benzo[7]annulene-5,8-diyl dicarboxylates. This reaction has been extended to syntheses of highly functionalized 2,2′-bibenzo[7]annulenes with four biphenyls bearing two sets of different propargyl carboxylates.

Full text of DOI:10.1016/j.tet.2016.07.060

Tetrahedron xxx (2016) 1e5
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0
Syntheses of 2,2 -bibenzo[7]annulenes by double Au-catalyzed
sequential activation of propargylic carboxylates
Young Ju Lee, Hoon Gu Heo, Chang Ho Oh *
Department of Chemistry and Research Institute of Natural Science, Hanyang University, Seongdong-gu, Seoul 04763, South Korea
a r t i c l e i n f o
a b s t r a c t
Article history:
We previously reported a novel Au-catalyzed sequential activation of two different propargyl carbox-
Received 8 June 2016
Received in revised form 22 July 2016
Accepted 25 July 2016
Available online xxx
ylates to 6-methylene-6H-benzo[7]annulene-5,8-diyl dicarboxylates. This reaction has been extended to
syntheses of highly functionalized 2,2 -bibenzo[7]annulenes with four biphenyls bearing two sets of
different propargyl carboxylates.
0
Ó 2016 Elsevier Ltd. All rights reserved.
Keywords:
Cyclization
Gold catalyst
Benzo[7]annulene
Propargyl carboxylate
Bisbenzoannulene
1
. Introduction
form a five-membered ring intermediate C1 (path b), that would
8
form Au-carbene complex C2. Note that such Au-carbenes can
9
10
As a result of the unique properties of gold(I) and gold(III)
complexes in carbon-carbon esystems, gold-catalyzed organic
undergo cyclopropanation or cyclopentanation to form a vari-
ety of cyclic compounds.
p
transformations have emerged as an extraordinary tool to create
1
diverse molecular complexity. Such electrophilic activation of
carbonecarbon multiple bonds toward a variety of nucleophiles
relies on interaction between gold catalysts (sometimes combining
2
with silver salts) and
p
-bonds of alkenes, alkynes, or allenes.
A
3
broad array of gold-catalyzed cycloisomerizations has been dis-
closed offering access to a plethora of new complex cyclic motifs in
4
a highly efficient manner.
Particular attention has been paid to Au-activated complexes
5
A of propargylic carboxylates (Scheme 1). Two different but
Scheme 1. Au-activations of propargylic carboxylates.
mechanistically related intermediates characterize these com-
petitive processes depending on the type of substrates: 1,2-
6
migration to gold-carbenes proceeds via the alkenylgold spe-
Recently, we have developed a novel Au-catalyzed cascade re-
action of 1-(2-(3-acetoxyprop-1-ynyl)phenyl)prop-2-ynyl acetate
1) and its derivatives which can provide a highly efficient access to
cies, whereas 1,3-migration forms allenoates via gold-assisted
1
[
3,3]-sigmatropic rearrangement. First, internal propargylic
(
6
carboxylates would undergo oxyaddition to gold-activated triple
-methylene-6H-benzo[7]annulene-5,8-diyl diacetate (2) and its
7
bond to give B1 (path a), which further proceeds to give alle-
11
derivatives in good to excellent yields (Scheme 2). Two different
roles of a gold catalyst were proposed for this reaction. First, the
reaction probably proceeds through the formation of allenoate in-
termediates B via 1,3-acyloxy transfer. And subsequent activation of
the terminal triple bond to D and final annulation to afford the
noates B2. Terminal propargyl carboxylates, however, would
12
corresponding seven-membered rings 2. Hydrolysis of 2 resulted
in quantitative formation of 2a.
*
Corresponding author. Fax: þ82 2 2298 0319; e-mail address: changho@hanyang.
ac.kr (C.H. Oh).
http://dx.doi.org/10.1016/j.tet.2016.07.060
0
040-4020/Ó 2016 Elsevier Ltd. All rights reserved.
Please cite this article in press as: Lee, Y. J.; et al., Tetrahedron (2016), http://dx.doi.org/10.1016/j.tet.2016.07.060

2
Y.J. Lee et al. / Tetrahedron xxx (2016) 1e5
this reaction to give 8a in 25% in toluene but not in dichloro-
methane (entries 9e10).
Table 1
Some studies on metal-catalyzed benzoannulations of 7a
Scheme 2. Mechanism for Au-catalyzed benzoannulation.
ꢀ
Entry
Catalyst [6 mol %]
Solvent
T [ C]
t [h]
Yield [%]
8
aa
8aab
1
2
3
4
5
6
7
8
9
10
NaAuCl
4
$2H
2
O
DCE
DCE
DCE
DCE
DCE
DCE
DCE
DCE
toluene
DCE
100
100
100
100
100
60
60
60
120
100
2
2
2
6
4
2
2
2
6
4
93
68
37
8
d
d
d
d
25
d
d
d
d
d
80
37
30
23
d
d
In continuation of this work, we wish to report our extension of
this work towards dimeric substrates which have two sets of bis(-
propargylic carboxylate) in a molecule connected by a single bond.
AuCl
AuCl
3
AuCl(PPh
AgOTf
3
)
Cu(OTf)
Sc(OTf)
2
2
. Results and discussion
3
In(OTf)
PtCl2
3
First, we prepared substrates for our study according to the
0
0
following sequences. [1,1 -biphenyl]-4,4 -diol was employed as the
PtCl
2
starting material. We first attempted to introduce two formyl
a
Isolated yield.
1
3
b
Conversion (%) determined by the 1H NMR integrations of CH
at 5.00 ppm of
2
groups in a step directly, using the procedure spoken by Duff,
14
15
8aa and at 4.94 ppm of 7a.
ReimereTiemann, or VilsmeiereHaak. All these formylations
resulted in a failure to obtain products in large quantities. Thus we
16
decided to do this in three steps: methylation, Ti-mediated for-
mylation, and demethylation. The resultant 4,4 -dihydroxy-
Since substrate 7b is a mixture of diastereomers due to its two
propargylic positions, the gold-catalyzed annulation product 8b
was a mixture of alkenyl geometric isomers (Eq. 1).
17
18
0
0
0
[
1,1 -biphenyl]-3,3 -dicarbaldehyde (4) was then triflated to afford
19
the bistriflate 5 in high yield. Then, Sonogashira cross-couplings
of the bistriflate 5 with four different propargylic alcohols (a, b, c,
and d) were carried out to give the products 6aed in good to ex-
cellent yields.20 Additions of ethynylmagnesium bromide into each
of 6aed followed by acetylation, provide the tetraacetates 7aed in
gram quantities (Scheme 3).
ð1Þ
Likewise, the product 8c from 7c was a mixture of isomers (Eq. 2).
Note that a remote double bond in 7c did not interfere this trans-
formation under the given conditions. Since both products 8b and
8c have three possible structures (EE, ZE, and EZ in double bond
configurations), we have hydrolyzed 8b and 8c by treatment with
sodium hydroxide in aqueous methanol to afford the products 9b
and 9c in over 95% yields, respectively.
Scheme 3. Preparations of substrates 7aed.
Since benzoannulation of 1 under gold catalysis proceeded well
giving the product 2 in almost quantitative yield, we expected
double annulation of substrates 7aed to occur in a similar fashion.
We first attempted to optimize the double benzoannulation of
substrate 7a under various catalytic conditions (Table 1).
ð2Þ
Gold compounds could catalyze the substrate 7a into the cor-
responding bisbenzoannulene 8a in varying yields (entries 1e4),
4 2
amongst which NaAuCl $2H O was the best catalyst for this
transformation affording 8a in 93% yield. Various catalysts were
surveyed to explore other possible outcomes. As expected, lewis
To prevent the formation of isomeric products and extend its
scope, we prepared a fourth substrate 7d, with a tertiary prop-
argylic acetate. Like 7a, 7d proceeded this gold-catalyzed ben-
zoannulation to give the expected product 8d in 76% yield (Eq. 3). In
contrast to 7a, 7d exhibited somewhat lower reactivity under gold-
catalyzed reaction conditions.
acids such as Ag(OTf), Cu(OTf)
to give the corresponding enal 8aa in varying conversions (entries
e8). Finally, we found that PtCl has a little catalytic activity for
2 3 3
, Sc(OTf) , and In(OTf) catalyzed 7a
5
2
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Y.J. Lee et al. / Tetrahedron xxx (2016) 1e5
3
spectra were recorded with an FTIR spectrometer. High-resolution
mass spectra (HRMS) were recorded with a Bruker TOF-Q spec-
trometer in the ESI mode. All reactions were monitored by TLC
ꢀ
analysis using Merck silica gel 60 A F-254 thin layer plates and
visualized by UV. Flash column chromatography was performed on
ꢀ
silica gel 60 A 10e40
m
m (from Merck Co). All reagents and solvents
ð3Þ
were of commercial grade and purified prior to use when
necessary.
0
0
0
4
.2. 4,4 -Dihydroxy-[1,1 -biphenyl]-3,3 -dicarbaldehyde (4)
In order to obtain the same series of products, each of 8a and 8d
was hydrolyzed to 9a and 9d (Eq. 4).
0
4
,4 -Dihydroxybiphenyl (3, 1.00 g, 5.37 mmol) was dissolved in
1
.0 M sodium hydroxide solution (21.0 mL, 21.0 mmol). Dimethyl
sulfate (2.0 mL, 21.1 mmol) was slowly added to this solution at
room temperature. The mixture was maintained under stirring for
1
2 h and then filtered, obtaining the product, which was further
0
purified by recrystallization with methanol to give the 4,4 -dime-
thoxy-1,1 -biphenyl (805.4 mg, 70%) as a white solid.
0
0
0
4
,4 -Dimethoxy-1,1 -biphenyl (805.4 mg, 3.76 mmol) in a dried
round-bottomed flask was dissolved in dry dichloromethane
ð4Þ
ꢀ
(
16 mL). The solution was cooled down to ꢁ78 C and TiCl
4
(tita-
nium tetrachloride, 2.4 mL, 21.8 mmol) was carefully added by
using a syringe. After stirring for 30 min, Cl CHOCH (dichlor-
2
3
omethyl methyl ether, 2.0 mL, 22.1 mmol) was added by using
a syringe and the resultant solution was stirred for 30 min at
ꢀ
ꢁ
78 C, then warmed to room temperature, and stirred for an hour.
In our previous report, because of elongated conjugation along
benzo[7]annulene-aryl group, the product 10b could not be iso-
lated due to its instability; thus it was immediately hydrolyzed by
using NaOH solution in methanol to 10c. A longer reaction time
caused gradually to decrease the yield of the product 10b resulting
into decomposing (Eq. 5).
The products 9aed have biaryl structures bearing extended
conjugations through the benzoannulene rings. From the above
results, we can summarize that dimeric substrates (7aed) bearing
Then the solution was quenched with water (8 mL) and 1.0 M HCl
solution (8 mL) and extracted twice with dichloromethane
(50 mLꢂ2). The combined organic layers were washed with brine
(40 mL), dried over anhydrous magnesium sulfate, concentrated
under reduced pressure. The solid residue was pure enough but
further purified by recrystallization with a mixture of dichloro-
0 0
methane and hexane to give the 4,4 -dimethoxy-[1,1 -biphenyl]-
3,3 -dicarbaldehyde (829.1 mg, 82%) as a white solid.
To a solution of 4,4 -dimethoxy-[1,1 -biphenyl]-3,3 -dicarbal-
dehyde (829 mg, 3.07 mmol) in dichloromethane (30 mL) was
added boron tribromide (0.70 mL, 7.39 mmol) at 0 C. The reaction
0
0
0
0
1
-(2-(3-acetoxyprop-1-ynyl)phenyl)prop-2-ynyl acetate under our
ꢀ
optimized conditions were converted into dendrons of 6-
methylene-6H-benzo[7]annulene-5,8-diyl diacetate derivatives
mixture was stirred for an hour at room temperature, then
quenched with a saturated sodium bicarbonate solution (30 mL).
The organic layer was extracted twice with dichloromethane
(50 mLꢂ2). The combined organic layers were washed with brine
(8aed) in good yields. Finally, we hydrolyzed the products 8aed to
give dendrons of 8-hydroxy-6-methyl-5H-benzo[7]annulen-5-one
derivatives 9aed in over 95% yields.
(
40 mL), dried over anhydrous magnesium sulfate, filtered, and
0
concentrated under reduced pressure to afford 4,4 -dihydroxy-
0
0
[
1,1 -biphenyl]-3,3 -dicarbaldehyde (4, 658.5 mg, 89%) as a pale
18
yellow solid.
ð5Þ
0
0
0
4
.3. 3,3 -Diformyl-[1,1 -biphenyl]-4,4 -diyl bis(triflate) (5)
0
0
0
To solution of 4,4 -dihydroxy-[1,1 -biphenyl]-3,3 -dicarbalde-
3
. Conclusion
hyde (4, 658.5 mg, 2.72 mmol) in dichloromethane (10 mL) was
added pyridine (1.0 mL, 12.4 mmol) and trifluoromethanesulfonic
anhydride (1.0 mL, 5.94 mmol) at 0 C. The reaction mixture was
stirred for an hour at the same temperature. The reaction was
quenched with water (5 mL) and 1.0 M HCl solution (5 mL). The
combined organic layers were extracted twice with dichloro-
methane (50 mLꢂ2), washed with brine (40 mL), dried over an-
hydrous magnesium sulfate, filtered and concentrated under
reduced pressure. The crude solid was purified by recrystallization
We have broadened the Au-catalyzed sequential activation
ꢀ
protocol to biaryl substrates bearing two propargyl carboxylates in
each phenyl group. The chemistry has the potential for preparation
of complex dendrimers since the present benzoannulation oc-
curred without any interference between two reaction centers.
4
4
. Experimental section
0
with a mixture of dichloromethane and hexane to give the 3,3 -
0
0
.1. General information
diformyl-[1,1 -biphenyl]-4,4 -diyl bis(trifluoromethanesulfonate)
ꢀ
1
(
5, 1.24 g, 90%, mp 107 C) as a pale yellow solid: H NMR (400 MHz,
CDCl
10.35 (s, 2H, CHO), 8.23 (d, J¼2.4 Hz, 2H), 7.96 (dd, J¼8.8,
2.4 Hz, 2H), 7.58 (d, J¼8.4 Hz, 2H); C NMR (100 MHz, CDCl
All isolated compounds were characterized on the basis of 1H
3
) d
13
13
NMR and C NMR spectroscopic data, IR spectra, and HRMS data.
3
)
All 1H NMR and C NMR spectra were recorded on a 400 MHz
13
d
186.2, 150.0, 139.1, 134.2, 129.1, 129.0, 123.6, 118.7 (q, J¼319 Hz); IR
1
ꢁ1
spectrometer with solvent resonances as the internal standard ( H
NMR: CDCl
(NaCl, cm ) 1708, 1602, 1479, 1427, 1249, 1214; HRMS (ESI) Calcd
13
þ
3
at 7.26 ppm; C NMR: CDCl
3
at 77.0 ppm). Infrared
for [C16H
8
F
6
NaO
8
2
S ]
requires m/z 528.9457, found m/z 528.9454.
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4
Y.J. Lee et al. / Tetrahedron xxx (2016) 1e5
0
0
4
.4. Synthesis of 4,4 -bis(3-hydroxyprop-1-yn-1-yl)-[1,1 -bi-
5.65e5.72 (m, 2H), 2.70 (s, 2H), 2.15 (d, J¼4.0 Hz, 6H), 2.13 (s, 6H),
13
0
phenyl]-3,3 -dicarbaldehyde (6a) and 6bed
1.60 (d, J¼6.8 Hz, 6H); C NMR (100 MHz, CDCl
3
) d 170.1, 169.5,
1
40.5, 138.5, 133.2, 127.6, 126.6, 121.5, 94.4, 81.0, 79.6, 76.0, 63.6,
0
0
0
ꢁ1
To solution of 3,3 -diformyl-[1,1 -biphenyl]-4,4 -diyl bis(tri-
fluoromethanesulfonate) (5, 1.24 g, 2.45 mmol) in dimethylforma-
60.7, 21.3, 21.2, 20.9; IR (NaCl, cm ) 1744, 1271, 1230, 1031; HRMS
(ESI) Calcd for [C34
589.1832. 7c (diastereomeris mixture, 78%): H NMR (400 MHz,
CDCl
þ
H30NaO
8
]
requires m/z 589.1833, found m/z
1
mide (10 mL) was added PdCl
palladium(II) dichloride, 172 mg, 0.25 mmol, 10 mol %), CuI
93.3 mg, 0.49 mmol, 20 mol %), propargyl alcohol (0.43 mL,
.38 mmol) using a micro syringe. Finally, to this mixture was added
triethylamine (3.0 mL, 21.5 mmol) under an argon atmosphere. The
reaction mixture was stirred for 2 h at 80 C, cooled down to 0 C,
quenched with water (5 mL) and 1 M HCl solution (5 mL). Extracted
twice with ethyl acetate (40 mLꢂ2) and the combined organic
layers were washed with brine (40 mL), dried over anhydrous
magnesium sulfate, filtered, and concentrated under reduced
2
(PPh
3
)
2
(bis(triphenylphosphine)
3
)
d
7.98 (s, 2H), 7.55 (q, J¼8.0 Hz, 4 H), 6.76e6.75 (m, 2H), 5.84
(
7
(m, 2H), 5.59 (m, 2H), 4.99 (s, 2H), 4.95 (d, J¼4.4 Hz 2H), 4.63 (s, 2H),
2.68 (d, J¼2.0 Hz, 2H), 2.14 (d, J¼6.8 Hz, 6H), 2.10 (s, 6H), 1.11 (d,
13
J¼12.8 Hz, 12H); C NMR (100 MHz, CDCl
3
) d 169.9, 169.3, 146.9,
ꢀ
ꢀ
140.4, 138.4, 133.1, 127.5, 126.5, 121.5, 111.2, 94.7, 81.4, 79.6, 76.0,
ꢁ1
63.6, 62.0, 47.2, 36.2, 27.5, 26.7, 21.2, 20.9; IR (NaCl, cm ) 3286,
2962, 1743, 1484, 1369, 1225, 1018; HRMS (ESI) Calcd for
þ
[C44
H
46NaO
8
]
requires m/z 725.3085, found m/z 725.3086. 7d
1
(diastereomeris mixture, 64%): H NMR (400 MHz, CDCl
3
) d 7.99 (s,
0
0
pressure to give 4,4 -bis(3-hydroxyprop-1-yn-1-yl)-[1,1 -bi-
2H), 7.54e7.59 (m, 4H), 6.79 (d, J¼2.0 Hz, 2H), 2.64 (d, J¼2.0 Hz, 2H),
0
1
13
phenyl]-3,3 -dicarbaldehyde (6a, 717 mg, 92%) as a white solid: H
NMR (400 MHz, Acetone)
10.56 (s, 2H, CHO), 8.18 (d, J¼1.6 Hz, 2H),
.09 (dd, J¼8.4, 2.0 Hz, 2H), 7.75 (d, J¼8.0 Hz, 2H), 4.55 (s, 2H), 3.40
2.15 (s, 6H), 2.08 (s, 6H), 1.76 (s, 12H); C NMR (400 MHz)
d 169.5,
d
169.4, 140.3, 138.2, 133.1, 127.5, 126.5, 121.8, 97.0, 80.61, 79.82, 75.8,
ꢁ1
8
(
72.1, 63.6, 29.0, 28.9, 22.0, 20.9; IR (NaCl, cm ) 1743, 1368, 1222,
1
þ
s, OH). 6b (diastereomeris mixture, 72%): H NMR (400 MHz,
CDCl
10.55 (s, 2H, CHO), 8.17 (d, J¼1.6 Hz, 2H), 7.84 (dd, J¼8.0,
.4 Hz, 2H), 7.66 (d, J¼8 Hz, 2H), 4.83e4.90 (m, 2H), 1.63 (d,
1017; HRMS (ESI) Calcd for [C34
H30NaO
8
]
requires m/z 617.2146,
3
)
d
found m/z 617.2148.
6
13
J¼6.8 Hz, 6H); C NMR (100 MHz, CDCl
3
) d 191.4,139.4,136.5,134.3,
4.6. Cycloisomerization of 7ae8a
1
32.0, 125.9, 125.6, 99.4, 79.5, 59.0, 24.4. 6c (diastereomeris mix-
1
ture, 93%): H NMR (400 MHz, CDCl
J¼2.0 Hz, 2H), 7.77e7.80 (m, 2H), 7.61 (d, J¼8.4 Hz, 2H), 5.91e5.98
m, 2H), 5.07 (d, J¼9.2 Hz, 2H), 5.03 (d, J¼2.0 Hz, 2H), 4.73e4.77 (m,
H), 2.3 (d, J¼4.8 Hz, 2H), 1.96 (t, J¼12.4 Hz, 4H), 1.15 (d, J¼4.8 Hz,
3
) d 10.51 (s, 2H, CHO), 8.10 (d,
To a 5 mL sealed tube charged with sodium tetrachloroaurate
dehydrate (2.2 mg, 6.1 mol, 6 mol %) was added substrate (7a,
5.1 mg, 0.102 mmol) in 1,2-dichloroethane (1.0 mL) via cannula
m
(
2
1
1
5
under an argon atmosphere. The reaction mixture was sealed and
13
2H); C NMR (100 MHz, CDCl
3
) d 191.4, 147.8, 139.3, 136.5, 134.2,
ꢀ
stirred at 100 C for 2 h. After the reaction was complete by TLC
32.0, 126.1, 125.5, 111.9, 99.5, 80.1, 61.0, 50.4, 36.4, 28.0, 26.8. 6d
mp 137 C, 74%): H NMR (400 MHz, CDCl
analysis, the reaction mixture was cooled down to room tempera-
ture, quenched with a drop of triethylamine, and concentrated
under reduced pressure. The concentrated residue was then rapidly
purified by flash silica gel chromatography by using a 1:1 mixture
ꢀ
1
(
3
)
d
10.51 (s, 2H, eCHO),
8
2
d
.08 (d, J¼1.6 Hz, 2H), 7.77 (dd, J¼8.0, 1.6 Hz, 2H), 7.59 (d, J¼8.0 Hz,
13
H), 2.65 (br s, 2H, eOH), 1.69 (s, 12H); C NMR (100 MHz, CDCl
191.5, 139.2,136.38, 134.2, 131.9, 126.1, 125.5,102.4, 77.6, 65.9, 31.4,
1.2.
3
)
of ethyl acetate and hexane to give the product (8a, 51.2 mg, 93%) as
3
1
a yellow oil: H NMR (400 MHz, CDCl
(
5
(
3
)
d
8.35 (d, J¼8.8 Hz, 2H), 8.10
s, 2H), 7.87 (d, J¼8.8 Hz, 2H), 7.68 (s, 2H), 7.39 (d, J¼2.0 Hz, 4H),
4
.5. Preparation of 7aed
13
.42 (s, 2H), 5.32 (s, 2H), 2.38 (s, 6H), 2.17 (s, 6H); C NMR
169.5, 169.1, 152.0, 148.9, 138.7, 135.3, 134.5,
28.4, 126.5, 126.3, 126.1, 122.5, 120.3, 107.9, 21.4, 21.2; IR (NaCl,
3
100 MHz, CDCl ) d
To a solution of 6a (717 mg, 2.25 mmol) in tetrahydrofuran
10 mL) was added 0.5 M solution of ethynylmagnesium bromide
12.0 mL, 6.00 mmol) in tetrahydrofuran at ꢁ78 C. The reaction
1
(
(
ꢁ1
cm ) 1761.51, 1625, 1369, 1210, 1019; HRMS (ESI) Calcd for
ꢀ
þ
[C
32
H26NaO
8
]
requires m/z 561.1522, found m/z 561.1520. All other
mixture was slowly warmed to room temperature and stirred for an
hour. Then, the reaction mixture was quenched with saturated
ammonium chloride solution (10 mL), extracted twice with diethyl
ether (50 mLꢂ2), and the combined organic layers were washed
with brine (40 mL), dried over anhydrous magnesium sulfate, fil-
tered, and concentrated under reduced pressure to give the crude
product. To the crude product in dichloromethane (10 mL) were
successively added triethylamine (3.0 mL, 21.5 mmol), 4-
dimethylaminopyridine (82.0 mg, 0.67 mmol), and acetic anhy-
substrates (7be7d) were subjected to the same conditions as re-
ported in the main text. Each of 8b and 8c are composed three
isomeric (ZZ, ZE, EE) products, which were directly hydrolyzed to
afford 9b and 9c in overall 78% and 62% yields, respectively. 8d
1
(
8
yellow oil, 72%): H NMR (400 MHz, CDCl
3
)
d
8.16 (d, J¼8.8 Hz, 2H),
.09 (s, 2H), 7.84 (d, J¼8.4 Hz 2H), 7.66 (d, J¼1.6 Hz, 2H), 7.34 (d,
13
J¼2.0 Hz, 2H), 2.36 (s, 6H), 2.10 (s, 6H), 1.88 (s, 6H), 1.63 (s, 6H);
NMR (100 MHz, CDCl ): 169.5, 169.3, 148.1, 138.8, 138.4, 134.9,
34.4, 129.3, 126.8, 126.4, 125.9, 125.1, 124.2, 119.7, 21.3, 20.9, 19.9,
C
3
d
1
1
ꢀ
dride (2.0 mL, 21.2 mmol) at 0 C. The reaction mixture was stirred
for an hour at the room temperature. The mixture was diluted with
water (30 mL) and extracted twice with dichloromethane
ꢁ
1
7.9; IR (NaCl, cm ) 1748, 1207, 1140, 1105; HRMS (ESI) Calcd for
þ
[C
36
H
34NaO
aa (yellow oil): H NMR (400 MHz, CDCl
H, CHO), 8.00 (d, J¼16.6 Hz, 2H), 7.85 (s, 2H), 7.67e7.59 (m, 4H),
8
] requires m/z 617.2146, found m/z 617.2147.
1
8
3
):
d
9.82 (d, J¼7.6 Hz,
(
50 mLꢂ2). The combined organic layers were washed with brine
2
6
(
1
1
(
40 mL), dried over anhydrous magnesium sulfate, filtered, and
13
.87 (dd, J¼16 Hz, 7.6 Hz, 2H), 5.00 (s, 4H), 2.18 (s, 6H); C NMR
): 193.9, 170.4, 149.5, 140.5, 136.4, 134.2, 130.6,
29.2, 125.1, 123.0, 91.0, 83.4, 52.8, 20.9; IR (NaCl, cm ) 1744, 1684,
concentrated under reduced pressure. The residue was purified by
flash silica gel chromatography by using a 1:2 mixture of ethyl
100 MHz, CDCl
3
d
ꢁ1
acetate and hexane to give the product (7a, 921 mg, diastereomeric
þ
377,1227,1138,1028; HRMS (ESI) Calcd for [C28
H22NaO
6
]
requires
1
mixture, 70%) as a yellow oil: H NMR (400 MHz, CDCl
3
)
d
8.01 (s,
m/z 477.1309, found m/z 477.1326.
2
H), 7.61e7.56 (m, 4H), 6.81 (d, J¼2.4 Hz, 2H), 4.94 (s, 4H), 2.71 (d,
13
J¼2.0 Hz, 2H), 2.15 (d, J¼5.2 Hz, 12H); C NMR (100 MHz, CDCl
3
)
d
170.3, 169.5, 140.6, 138.7, 133.2, 127.6, 126.6, 121.3, 90.0, 82.8, 79.5,
4.7. General procedure for hydrolysis of 8aed to 9aed
ꢁ1
76.1, 63.5, 52.6, 20.8; IR (NaCl, cm ) 1743, 1484, 1371, 1222, 1022;
þ
HRMS (ESI) Calcd for [C32
m/z 561.1522. 7b (diastereomeris mixture, 75%):
H26NaO
8
]
requires m/z 561.1520, found
A 1.0 M solution of sodium hydroxide (0.5 mL, 0.5 mmol) was
1
H
NMR
slowly added to each solution of 8aed (0.1 mmol) in methanol
ꢀ
(
400 MHz, CDCl 8.00 (s, 2H), 7.60e7.55 (m, 4H), 6.79 (s, 2H),
3
)
d
(2 mL) at 0 C. The reaction was complete within 30 min at room
Please cite this article in press as: Lee, Y. J.; et al., Tetrahedron (2016), http://dx.doi.org/10.1016/j.tet.2016.07.060

Y.J. Lee et al. / Tetrahedron xxx (2016) 1e5
5
temperature. Extractive workup and flash column chromatography
gave 9aed in over 95% yields.
Munoz, M. P. Org. Biomol. Chem. 2012, 10, 3584; (c) Chen, B.; Fan, W.; Chai, G.;
Ma, S. Org. Lett. 2012, 14, 3616; (d) Weber, D.; Gagne, M. R. Chem. Sci. 2013, 4,
335; (e) Alcaide, B.; Almendros, P.; Cembellin, S.; Campoa, T. M.; Fernandezc, I.
ꢀ
1
9
a (white solid, mp 169e172 C): H NMR (400 MHz, DMSO-d
6
):
Chem. Commun. 2013, 1282; (f) Hashmi, A. S. K.; Lothschtz, C.; Dcpp, R.; Ac-
kermann, M.; Becker, J. D. B.; Rudolph, M.; Scholz, C.; Rominger, F. Adv. Synth.
Catal. 2012, 354, 133.
d
10.18 (s, 2H, OH), 8.56 (d, J¼8.8 Hz, 2H), 8.24 (s, 2H), 7.86 (d,
13
J¼8.8 Hz, 2H), 7.67 (s, 2H), 7.48 (s, 2H), 2.72 (s, 6H); C NMR
100 MHz, DMSO-d ): 201.3, 154.3, 137.3, 136.3, 135.8, 126.2, 124.4,
23.7, 123.6, 121.7, 114.0, 30.0; IR (KBr, cm ) 3132, 1654, 1603, 1363,
231; HRMS (ESI) Calcd for [C24 18NaO
]þ requires m/z 393.1097,
found m/z 393.1095. 9b (white solid, mp 260e262 C): H NMR
400 MHz, DMSO-d
8.38 (d, J¼8.4 Hz, 2H), 8.23 (s, 2H), 7.84 (dd,
J¼8.8,1.2 Hz, 2H), 7.59 (d, J¼2.4 Hz, 2H), 7.45 (d, J¼2.0 Hz, 2H), 3.11 (q,
3
. (a) Soriano, E.; Marco-Contelles, J. J. Org. Chem. 2012, 77, 6231; (b) Wang, Q.;
Aparaj, S.; Akhmedov, N. G.; Patersen, J. L.; Shi, X. Org. Lett. 2012, 14, 1334; (c)
Wu, H.; Yang, C.; Hwang, L.; Wu, M. Org. Biomol. Chem. 2012, 10, 6640; (d)
Ghebreghiorgis, T.; Biannic, B.; Kirk, B. H.; Ess, D. H.; Aponick, A. J. Am. Chem.
Soc. 2012, 134, 16307; (e) Fang, R.; Yang, L. Organometallics 2012, 31, 3043; (f)
Romero, N. A.; Klepser, B. M.; Anderson, C. E. Org. Lett. 2012, 14, 874; (g) Liu, L.;
Hammond, G. B. Chem. Asian J. 2009, 4, 1230.
(
1
6
d
ꢁ1
1
H
4
ꢀ
1
(
6
) d
4
. (a) Jim eꢁ nez, N. E.; Echavarren, A. M. Chem. Rev. 2008, 108, 3326; (b) Michelet, V.;
1
3
Toullec, P. Y.; Genet, J. P. Angew. Chem. 2008, 120, 4338 Angew. Chem. Int. Ed.
J¼6.8 Hz, 4H), 1.16 (t, J¼7.2 Hz, 6H); C NMR (100 MHz, DMSO-d
6
)
2
008, 47, 4268; c) García- García, P.; Martínez, A.; Sanju aꢁ n, A. M.; Fern ꢁa ndez-
d
204.5, 154.4, 137.3, 137.1, 135.7, 126.0, 124.3, 123.5, 123.5, 120.2,
13.3, 34.7, 8.5; IR (KBr, cm ) 3304, 1665, 1618, 1384, 1224; HRMS
Rodríguez, M. A.; Sanz, R. Org. Lett. 2012, 13, 4970; (d) Naoe, S.; Suzuki, Y.;
Hirano, K.; Inaba, Y.; Oishi, S.; Fujii, N.; Ohno, H. J. Org. Chem. 2012, 77, 4907.
ꢁ
1
1
þ
5. (a) Shapiro, N. D.; Toste, F. D. J. Am. Chem. Soc. 2008, 130, 9244; (b) Wang, S.;
Zhang, G.; Zhang, L. Synlett 2010, 692; (c) Liu, L.; Zhang, L. Angew. Chem. 2012,
124, 7413 Angew. Chem. Int. Ed. 2012, 51, 7301; (d) Bhunia, S.; Liu, R. Pure Appl.
Chem. 2012, 84, 1749.
. (a) Luo, Y.; Ji, K.; Li, Y.; Zhang, L. J. Am. Chem. Soc. 2012, 134, 17412; (b) Xiao, Y.;
Zhang, L. Org. Lett. 2012, 14, 4662; (c) He, W.; Xie, L.; Xu, Y.; Xiang, J.; Zhang, L.
Org. Biomol. Chem. 2012, 10, 6640.
(
ESI) Calcd for [C26
H
22NaO
21.1410. 9c (yellow solid, mp 178e180 C): H NMR (400 MHz,
8.48 (d, J¼8.8 Hz, 2H), 8.18 (s, 2H), 7.84 (dd, J¼8.8,
.6 Hz, 2H), 7.83 (d, J¼2.4 Hz, 2H), 7.52 (d, J¼2.0 Hz 2H), 5.86 (dd,
J¼17.6, 10.8 Hz, 2H), 5.03e4.97 (m, 4H), 3.04 (t, J¼8 Hz, 4H), 1.81 (t,
4
]
requires m/z 421.1410, found m/z
ꢀ
1
4
6
Acetone-D ) d
1
6
13
J¼8 Hz, 4H), 1.09 (s, 12H); C NMR (100 MHz, Acetone-D
6
)
d
204.4,
7. (a) Roithov, J.; Jankov, S.; Jaskov, L.; Vna, J.; Hybelbauerov, S. Angew. Chem. 2012,
24, 8503 Angew. Chem. Int. Ed. 2012, 51, 8378; (b) Egi, M.; Azechi, K.; Akaia, S.
Adv. Synth. Catal. 2011, 353, 287; (c) Kim, S.; Lee, P. H. Adv. Synth. Catal. 2008,
50, 547.
1
1
1
55.3,148.6,139.3,139.0,137.2,127.3,125.6,125.3,124.8,120.6,114.2,
ꢁ1
11.7, 38.5, 37.2, 37.0, 27.0; IR (KBr, cm ) 3384, 2959, 1663, 1621,
3
þ
1221; HRMS (ESI) Calcd for [C36
H
38NaO
4
]
requires m/z 557.2662,
8. (a) Ye, L.; Wang, Y.; Aue, D. H.; Zhang, L. J. Am. Chem. Soc. 2012, 134, 31; (b)
Hashmi, A. S. K.; Braun, I.; N o€ sel, P.; Sch a€ dlich, J.; Wieteck, M.; Rudolph, M.;
ꢀ
1
found m/z 557.2649. 9d (brown solid, mp 219e222 C): H NMR
Rominger, F. Angew. Chem. 2012, 124, 4532 Angew. Chem. Int. Ed. 2012, 51, 4456;
(
(
2
1
400 MHz, Acetone-D
6
)
d
9.04 (s, OH, 2H), 8.26 (d, J¼8.8 Hz, 2H), 8.18
(
c) Hashmi, A. S. K.; Wieteck, M.; Braun, I.; N o€ sel, P.; Jongbloed, L.; Rudolph, M.;
s, 2H), 7.83 (d, J¼8.2 Hz, 2H), 7.53 (d, J¼4.4 Hz, 4H), 3.56e3.63 (m,
Rominger, F. Adv. Synth. Catal. 2012, 354, 555; (d) Hashmi, A. S. K.; Braun, I.;
Rudolph, M.; Rominger, F. Organometallics 2012, 31, 644; (e) Gaillard, S.; Cazin,
C. S. J.; Nolan, S. P. Acc. Chem. Res. 2012, 45, 778; (f) Krause, N.; Winter, C. Chem.
Rev. 2011, 111, 1994; (g) Furstner, A.; Davies, P. W. Angew. Chem. 2007, 119, 3478
Angew. Chem. Int. Ed. 2007, 46, 3410.
1
3
H),1.22 (d, J¼6.8 Hz,12H); C NMR (100 MHz, Acetone-D
6
) d 208.3,
55.4, 139.4, 139.4, 137.1, 127.1, 125.7, 125.6, 124.7, 119.5, 113.7, 40.1,
ꢁ
8.9; IR (KBr, cm ) 3139, 1754, 1401; HRMS (ESI) Calcd for
1
1
þ
9
. (a) Johansson, M. J.; Gorin, D. J.; Staben, S. T.; Toste, F. D. J. Am. Chem. Soc. 2005,
28 26 4
[C H O Na] requires m/z 449.1723, found m/z 449.1713.
1
27, 18002; (b) Moreau, X.; Goddard, J.; Bernard, M.; Lemi eꢂ re, G.; L oꢁ pez-Ro-
mero, J. M.; Mainetti, E.; Marion, N.; Mouri eꢂ s, V.; Thorimbert, S.; Fensterbank,
L.; Malacria, M. Adv. Synth. Catal. 2008, 350, 43; (c) Yeom, H.; Shin, S. Org. Bi-
omol. Chem. 2013, 11, 1089; (d) Hashmi, A. S. K.; Wieteck, M.; Braun, I.; Rudolph,
M.; Rominger, F. Angew. Chem. 2012, 124, 10785 Angew. Chem. Int. Ed. 2012, 51,
Acknowledgements
This work was supported by a National Research Foundation of
Korea (NRF) grant funded by the Korean government (NRF-
10633; (e) Qiana, D.; Zhang, J. Chem. Commun. 2011, 11152; (f) Solorio-Alvarado,
C. R.; Wang, Y.; Echavarren, A. M. J. Am. Chem. Soc. 2011, 133, 11952.
2
015R1D1A1A02061609). This is dedicated for retirement of Prof.
10. (a) Karmaka, S.; Kim, A.; Oh, C. H. Synthesis 2009, 194; (b) Maule oꢁ n, P.; Krinsky,
J. L.; Toste, F. D. J. Am. Chem. Soc. 2009, 131, 4513; (c) Candish, L.; Lupton, D. W. J.
Am. Chem. Soc. 2013, 135, 58; (d) Illera, D. S.; Suresh, S.; Moccia, M.; Bellini, G.;
Saviano, M.; Adamo, M. F. A. Tetrahedron Lett. 2012, 53, 1808; (e) Ma, Z.; He, S.;
Song, W.; Hsung, R. P. Org. Lett. 2012, 14, 5736.
Gary H. Posner from Johns Hopkins University.
Supplementary data
1
1
1. Oh, C. H.; Kim, J. H.; Oh, B. K.; Park, J. R.; Lee, J. H. Chem.dEur. J. 2013, 19, 2592.
2. (a) Xia, X.; Song, X.; Wang, N.; Wei, H.; Liua, X.; Liang, Y. RSC Adv. 2012, 2, 560;
b) Kramer, S.; Skrydstrup, T. Angew. Chem. 2012, 124, 4759 Angew. Chem. Int. Ed.
Supplementary data (Copies of 1H and 13C NMR spectra for
compounds 7aed, 8a, 8aa, 8d, 9aed) associated with this article
can be found in the online version, at http://dx.doi.org/10.1016/
j.tet.2016.07.060. These data include MOL files and InChiKeys of the
most important compounds described in this article.
(
2012, 51, 4681; (c) Takaki, K.; Shiraishi, K.; Okinaga, K.; Takahashi, S.; Ko-
meyama, K. RSC Adv. 2011, 1, 1799; (d) Hopkinson, M. N.; Ross, J. E.; Giuffredi, G.
T.; Gee, A. D.; Gouverneur, V. Org. Lett. 2010, 12, 4904.
1
3. Mastalerz, M.; Schneider, M. W.; Oppel, I. M. Chem.dEur. J. 2012, 18, 4156.
14. Elizbarashvili, E.; Matitaishvili, T.; Topuria, K. J. Braz. Chem. Soc. 2007, 18, 1254.
5. Yong, Q.; Jian-jun, W.; Rong, Z.; Yan-mei, X. Faguang Xuebao 2014, 35, 660.
6. Micheloni, M.; Fusi, V.; Ambrosi, G.; Formica, M.; Giorgi, L.; Macedi, E.; Pon-
tellini, R. Inorganica. Inorg. Chim. Acta 2009, 362, 2667.
7. Narashima Moorthy, J.; Natarajan, R.; Venugopalan, P. J. Mol. Struct. 2005, 741,
07.
8. Tzur, E.; Ben-Asuly, A.; Diesendruck, C. E.; Goldberg, I.; Lemcoff, N. G. Angew.
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1
1
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Please cite this article in press as: Lee, Y. J.; et al., Tetrahedron (2016), http://dx.doi.org/10.1016/j.tet.2016.07.060