Bsi(OTf)3-mediated tandem annulation of 1-aryl isochroman-3-ones with oxygenated arenes: One-pot synthesis of polyoxygenated homotriptycenes

Article abstract of DOI:10.1039/d1ob00606a

Bi(OTf)3 (bismuth triflate)-mediated one-pot tandem annulation of oxygenated 1-aryl isochroman-3-ones with oxygenated arenes provides polyoxygenated homotriptycenes in moderate to good yields in MeNO2 at reflux (101 °C) for 10 h under an air atmosphere and easy-operational conditions via intermolecular and intramolecular Friedel-Crafts type procedures. A plausible mechanism is proposed and discussed. This protocol provides a highly effective ring-closure via three carbon-carbon (C-C) bond formations.

Full text of DOI:10.1039/d1ob00606a

Organic &
Biomolecular Chemistry
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PAPER
Bsi(OTf) -mediated tandem annulation of 1-aryl
3
isochroman-3-ones with oxygenated arenes:
one-pot synthesis of polyoxygenated
homotriptycenes†
Cite this: Org. Biomol. Chem., 2021,
9, 4733
1
a,b
a
a
a
Meng-Yang Chang,
*
Chun-Yi Lin, Shin-Mei Chen and Yu-Ting Hsiao
3
Bi(OTf) (bismuth triflate)-mediated one-pot tandem annulation of oxygenated 1-aryl isochroman-3-
ones with oxygenated arenes provides polyoxygenated homotriptycenes in moderate to good yields in
MeNO2 at reflux (101 °C) for 10 h under an air atmosphere and easy-operational conditions via inter-
molecular and intramolecular Friedel–Crafts type procedures. A plausible mechanism is proposed and
discussed. This protocol provides a highly effective ring-closure via three carbon–carbon (C–C) bond
formations.
Received 30th March 2021,
Accepted 4th May 2021
DOI: 10.1039/d1ob00606a
rsc.li/obc
formation of substituted homotriptycenes has been thoroughly
investigated by Cao et al., including (i) benzylation of 10H-
Introduction
The family of triptycene that contains a rigid three-pronged anthracen-9-one, (ii) the reduction of the resulting 10-benzy-
framework can be utilized as versatile molecular motors, lanthracen-9-one, and (iii) the intramolecular ring-closure of
unique electro- and photochemical sensitizers, potential bio- the corresponding 10-benzylanthracen-9-ol in the presence of
1
6
active molecules and functionalized Fréchet-type dendrimers.
4
Brønsted acid. By TiCl -mediated [4 + 3] cycloaddition of
Owing to these important synthetic applications in construct- 1-arylcyclopropane and anthracene, Ivanova et al. developed a
7
ing diversified structures, many attempts to prepare the tripty- method for preparing thieno-fused homotriptycenes.
2
cene derivatives have been reported. Compared with these Therefore, further investigation of a one-pot, efficient and
members, however, there are few reports on the synthesis of easy-operational synthetic method for substituted homotripty-
substituted homotriptycene (tribenzobicyclo[3.2.2]nonatriene), cene is still highly desired.
3
–7
as shown in Scheme 1.
In 1970, Cristol and Pennelle described the first synthesized
homotriptycenes via a Wagner-type ring enlargement of
3
Results and discussion
1
-aminomethyltriptycenes. By the thermal dehydrogenation
of anellated dibenzohomobarrelenes, Szeimies et al. also
reported the second synthetic route. Later, Saito et al.
We recently explored the synthetic application of oxygenated
arylacetic acid 1 for one-pot synthesis, and established the
4
explored an alternative method using an intermolecular cyclo-
1-aryl isochroman-3-one 2 via a trifluoroacetic anhydride
5
addition of strained benzocyclopropene with anthracene. In
(
(
TFAA) promoted carboxy-Pictet–Spengler annulation in MeCN
Scheme 2). For the preparation of the skeleton of 1-aryl iso-
spite of these advancements, some problems exist in the
abovementioned papers, such as multi-step routes, compli-
cated reaction conditions, the lack of broad substrate general-
ity, and prefunctionalized fragments. A three-step route for the
8
chroman-3-one, many efforts using elegant synthetic routes
a
Department of Medicinal and Applied Chemistry, Kaohsiung Medical University,
Kaohsiung 807, Taiwan. E-mail: mychang@kmu.edu.tw
b
Department of Medical Research, Kaohsiung Medical University Hospital,
Kaohsiung 807, Taiwan
†
Electronic supplementary information (ESI) available: Scanned photocopies of
NMR spectral data for all compounds and X-ray analysis data of 5a and 5w-2
were supported. CCDC 1938168–1938169. For ESI and crystallographic data in
CIF or other electronic format see DOI: 10.1039/d1ob00606a
Scheme 1 Structures of triptycene, homotriptycene and polyoxyge-
nated homotriptycene.
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However, no desired 5a was detected, and 4a was isolated at
a 51% yield along with a 38% yield of the starting material 2a
(
entry 1). By elongating the time from 5 to 10 h, the yield of 4a
was increased to 92% (entry 2), and 5a was not obtained. With
the results in hand, the reaction temperature was adjusted to
70 °C. After 5 and 10 h, 5a was generated at 40% and 78%
yields, and 4a was isolated at 48% and 15% yields (entries 3
and 4). The two ratios of 5a and 4a are nearly 1 : 1 and 5 : 1. By
elongating the time (10 h) and elevating the temperature
Scheme 2 Our route of polyoxygenated homotriptycene.
(
70 °C), the yield of 5a was increased. To improve the yield of
5
a, the temperature was adjusted to reflux (101 °C) next.
On the basis of 5 and 10 h conditions (entries 5 and 6), we
have also been well-documented due to its specific chemo-
selectivity and diversified bioactivity. In continuation of the
9
,10
found that 10 h provided a better yield (88%) than 5 h (70%)
in the formation of 5a. However, after 5 h and 10 h, the
remaining amounts of 4a were 20% and traces, respectively. In
order to consume 4a, the time was elongated further to 15 h
research on Bi(OTf) -promoted diversified reactions,
we
3
present a Bi(OTf)
3
-mediated synthesis of polyoxygenated
homotriptycene by a one-pot tandem Friedel–Crafts type
tandem annulation of 1-aryl isochroman-3-one 2 with oxyge-
(
entry 7). Although 4a was formed in trace amounts, 5a was
2
nated arene 3 in MeNO via three carbon–carbon (C–C) bond
obtained at slightly lower yields (82%). From the results, we
envisioned that the reflux temperature (101 °C) and an appro-
priate elongated time (10 h) could increase the yield of 5a.
Based on the reaction conditions, catalytic amounts of Bi
formations (green marks). In Table 1, the initial study com-
1
2
menced with the treatment of 2a ((R O) = 4,5-(MeO) , (R O) =
n
2
n
3
3
,4-(MeO)
2 n 2
, 1.0 mmol) and veratrole (3a, (R O) = 1,2-(MeO) ,
1
.1 mmol) in MeNO2 (20 mL) for 5 h in the presence of Bi
(
OTf)
to 40 mol%, however, no better yields (85%) of 5a were
observed (entry 8). By diminishing the amounts of Bi(OTf)
3
were examined. After controlling the amounts from 30
(
OTf) (30 mol%).
3
3
(
(
30 → 20 mol%), the isolated yield was decreased to 78%
entry 9). Compared with 30 mol% amounts (entry 6), entries 8
a
Table 1 Annulation conditions
and 9 showed that there were excess (40%) and insufficient
20%) amounts of Bi(OTf) , so that the reaction could not be
(
3
triggered completely. Subsequently, the use of various com-
mercially available metal triflates was investigated for the for-
mation of 5a (entries 10–17). These screened catalysts, which
included catalytic amounts (30 mol%) of In(OTf) , Fe(OTf) , Sc
3
2
3
(
OTf)
3
, Ga(OTf)
3
, Cu(OTf)
2
, Sn(OTf)
2
, Hg(OTf)
and AgOTf,
provided different yield ratios of 5a and 4a, respectively.
Entries 10–13 showed that the trivalent metal complex pro-
vided 5a as a major product for different distributed ratios of
5a and 4a (8 : 1–2 : 1), and similar yield ratios of 5a and 4a
(∼1 : 1) were shown in entries 14–16 by the use of a bivalent
metal complex. In entry 17, interestingly, AgOTf only provided
a 13% yield of 4a and recovered 58% of 2a. However, no
desired 5a was detected. From these experimental results, we
thus found that different valent metal triflates provided
different results for the distributing ratios of 5a and 4a.
On the basis of the refluxing MeNO2 and the elongated
time (10 h) (entries 6–17), a reasonable explanation could be
that the bismuth ion was tighter to chelate with oxygenated
substituents between carbonyl and methoxy groups than
mono-, di- or other tri-valent metal ions. Thus, it was easier to
generate bridged skeleton 5a than 4a with a carboxyl arm via
the tandem Friedel–Crafts arylation processes. With these
b
b
Entry
M(OTf)
n
Solvent
Temp
Time
4a %
5a %
c
d
1
Bi(OTf)
Bi(OTf)
Bi(OTf)
Bi(OTf)
Bi(OTf)
Bi(OTf)
Bi(OTf)
Bi(OTf)
Bi(OTf)
In(OTf)
Fe(OTf)
Sc(OTf)
Ga(OTf)
Cu(OTf)
Sn(OTf)
Hg(OTf)
AgOTf (30)
Bi(OTf)
Bi(OTf)
Bi(OTf)
Bi(OTf)
Bi(OTf)
3
3
3
3
3
3
3
3
3
3
(30)
(30)
(30)
(30)
(30)
(30)
(30)
(40)
(20)
(30)
(30)
(30)
(30)
MeNO
MeNO
MeNO
MeNO
MeNO
MeNO
MeNO
MeNO
MeNO
MeNO
MeNO
MeNO
MeNO
MeNO
MeNO
MeNO
MeNO
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
25
25
70
70
5
10
5
10
5
51
92
48
15
—
—
d
2
3
4
5
6
7
8
9
40
78
70
88
82
85
78
78
78
69
60
47
42
42
101
101
101
101
101
101
101
101
101
101
101
101
101
84
20
10
15
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
Trace
Trace
Trace
12
10
12
20
29
42
45
10
11
12
13
14
15
16
17
18
19
20
21
22
3
3
3
2
(30)
(30)
(30)
2
2
50
13
79
c
d
—
—
—
—
d
3
3
3
3
3
(30)
(30)
(30)
(30)
(30)
(CHCl)
MeCN
DMF
2
d
82
76
e
e
153
101
101
—
3
results in hand, we found that 30 mol% of Bi(OTf) was the
most reactive and used catalyst compared to other metal tri-
flates derivatives. Solvent screening was performed next,
during which (CH Cl) and MeCN provided only 4a at 79%
2 2
and 76% yields, respectively, while no desired 5a was detected
f
MeNO
MeNO
2
Trace
Trace
88
85
g
2
a
The reactions were run on a 1.0 mmol scale with 2a, 3a (1.1 equiv.),
M(OTf) (mol%), temp (°C), solvent (20 mL), time (h). Isolated yields.
a (for entry 1, 38%; for entry 17, 58%) was recovered. No detection.
Complex products. Under a nitrogen atmosphere. Dry MeNO
b
n
c
d
2
e
f
g
2
.
(entries 18 and 19). Entry 20 showed that DMF provided
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complex products because refluxing DMF forced the decompo- new carbon–carbon bond formations (green). Subsequently, Bi
sition of Bi(OTf) . Under nitrogen atmosphere, 5a was (OTf) hydrate was regenerated by forming in situ HOBi(OTf)
2
3
3
obtained in an 88% yield (entry 21). The results meant that air and HOTf. From the possible mechanism, we found that the
atmosphere (entry 6) and nitrogen atmosphere (entry 21) pro- combination of Bi(OTf) could efficiently organize a continu-
3
vided same yield. By use of dry MeNO , the yield of 5a was pro- ous sequence of one intermolecular Friedel–Crafts type substi-
2
duced in an 85% yield (entry 22). For entries 21 and 22, we tution and two intramolecular ring-closures.
understood that oxygen and water did not affect the overall
To study the scope of this route (Table 2), treatment of
reaction process. The structure of 5a was determined by single- different multi-oxygenated 1-aryl isochroman-3-ones 2a–2f
1
1
1
2
crystal X-ray analysis.
(R O = dimethoxy, dioxymethylene; R O = dimethoxy, dioxy-
3
On the basis of our experimental results, a plausible methylene, trimethoxy) with oxygenated arenes 3a–d (R O =
Friedel–Crafts type tandem annulation mechanism for the for- dimethoxy, dioxymethylene, di-n-butoxy, di-n-octoxy) was
mation of 4a and 5a is illustrated in Scheme 3. Initially, 2a reacted with catalytic amounts (30 mol%) of Bi(OTf)
3
to give
reacted with Bi(OTf) -chelated veratrole 3a to obtain A via the polyoxygenated homotriptycenes 5a–5q based on optimal con-
3
1
2
3
involvement of the carbonyl group on 2a. Then, the methoxy ditions. By controlling the R , R , and R substituents on three
group of 3a promoted an intermolecular para-carbon of the arenes as the dioxygenated or trioxygenated groups, 5a–5q
electron-rich benzene ring to conjugate into the C1-position of were isolated at good to excellent yields (86%–96%, entries
3
3
a. After the ring-opening of isochroman-3-one ring, first, a 1–17). After elongating the carbon chain (R O) from methoxy
3 4 9 8
new carbon–carbon bond was formed (green). Following this, (CH O) to n-butoxy (C H O) or n-octoxy (C H17O) on the arene
the releasing triflate anion-mediated deprotonation of A led to group of 3, the isolated yields were similar. The results show
B and triflic acid by the dehydrogenative aromatization pro- that the different aromatic groups were well-tolerated. In par-
2
cedure. Under a refluxing MeNO
2
/10 h condition, the bismuth- ticular, for the reaction of 3a with 2g having a 3-methoxy (R =
chelated carboxylate on B could be installed by two kinds of 3-MeO), the desired 5r was isolated at a 60% yield along with a
routes. One was the direct protonation of bismuth-chelated 30% yield of 5r–1 (Scheme 4, eqn (1)). The reason behind the
carboxylate on B to achieve 4a (a minor route). Another was action is that the electron-donating efficiency of the mono-C3-
intramolecular Friedel–Crafts type arylation between the methoxyphenyl group was weaker than the dimethoxyphenyl
bismuth-chelated carboxylate and two oxygenated arenes. With group such that non-bridged tricyclic dibenzosuberone skel-
the para-methoxy groups on the electron-rich arene promoting etons could be generated as minor products during intra-
a twice intramolecular ring-closure, 5a could be generated by molecular Friedel–Crafts type procedure. Furthermore, Bi
paths a → b (for C1) and b → a (for C2), respectively for two
a
Table 2 Synthesis of 5a–5q
1
2
3
b
Entry
2, (R O)
n
=, (R O)
n
=
3, (R O)
n
=
5 , %
1
2
3
4
5
6
7
8
9
2a, 4,5-(MeO)
2a, 4,5-(MeO)
2a, 4,5-(MeO)
2a, 4,5-(MeO)
2b, 4,5-(MeO)
2b, 4,5-(MeO)
2
2
2
2
, 3,4-(MeO)
, 3,4-(MeO)
, 3,4-(MeO)
, 3,4-(MeO)
2
2
2
2
3a, 1,2-(MeO)
2
5a, 88
5b, 89
5c, 87
5d, 90
5e, 94
5f, 90
5g, 92
5h, 92
5i, 90
5j, 96
5k, 90
5l, 89
5m, 90
5n, 86
5o, 90
5p, 94
5q, 89
2 2
3b, 1,2-CH O
3c, 1,2-(nBuO)
3d, 1,2-(nOctO)
3d, 1,2-(nOctO)
2
2
2
, 3,4,5-(MeO)
, 3,4,5-(MeO)
3
3
2
2
3c, 1,2-(nBuO)
3b, 1,2-CH
3d, 1,2-(nOctO)
3c, 1,2-(nBuO)
3a, 1,2-(MeO)
3b, 1,2-CH
3c, 1,2-(nBuO)
3a, 1,2-(MeO)
3b, 1,2-CH
3a, 1,2-(MeO)
3b, 1,2-CH
3c, 1,2-(nBuO)
2
2c, 4,5-(MeO)
2d, 4,5-CH
2e, 4,5-CH
2
, 3,4-CH
, 3,4,5-(MeO)
, 3,4-(MeO)
O
2 2
2 2
O
2
O
O
2
3
2
2
2
2
2
10
11
12
13
14
15
16
17
2b, 4,5-(MeO)
2b, 4,5-(MeO)
2
, 3,4,5-(MeO)
2
, 3,4,5-(MeO)
3
3
2
O
2 2
2d, 4,5-CH
2
O
2
, 3,4,5-(MeO)
3
2
2e, 4,5-CH
2e, 4,5-CH
2
O
O
2
, 3,4-(MeO)
, 3,4-(MeO)
2
2
O
2 2
2
2
2
2d, 4,5-CH
2
O
2
, 3,4,5-(MeO)
3
2
O
2 2
2f, 4,5-CH
2f, 4,5-CH
2
O
2
, 3,4-CH
, 3,4-CH
2
O
O
2
2
O
2
2
2
2
a
The reactions were run on a 1.0 mmol scale with 2, 3 (1.1 equiv.), Bi
(200 mg, 30 mol%), reflux (101 °C), MeNO (20 mL), 10 h.
Isolated yields.
(
OTf)
3
2
b
Scheme 3 Plausible mechanism.
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Scheme 4 Synthesis of 5r, 5r-1–5w-1 and 5w-2.
3
(OTf) -mediated annulation of 5r–1 provided 5r in a 93% yield
under the extending time (10 h) conditions. The extending
time could trigger the conversion from 5r–1 to 5r completely.
From the above results, we found that all arenes on 2 and 3
required the dioxygenated groups to construct a rigid core skel-
eton of homotriptycene.
To demonstrate the plausibility, an extension of the Bi
3
(OTf) -mediated tandem annulation on treatment of 2h–2l
with 3a was examined next (Scheme 4, eqn (2)). When the Ar
group was exchanged from the o-dioxygenated aryl group to
other aryl groups (Ar = 4-MeOC
6 4
H , phenyl, 2-naphthyl, 3,4-
Scheme 5 Synthesis of 5x–5z.
Cl C H and 3,4-F C H ), however, only tricyclic dibenzosuber-
2
6
3
2
6
3
ones 5s-1–5w-1 were provided at a range of 80%–87% yields.
The results show that the dioxygenated group on the Ar group
was a very important factor in promoting the formation of a
bicyclic tribenzobicyclo[3.2.2]core. Interestingly, 5w-2 with a
cyclic dibenzodione could be obtained at a trace amount (8%
yield) since the 3,4-difluorophenyl group-mediated the autoxi-
dation of the α-position on 5w-1 under an air atmosphere con-
dition. The structure of 5w-2 was determined by single-crystal
To understand the electronic influence of heteroaromatics
on 3, thiophene (3f) was examined under the above optimal
reaction conditions, as shown in Scheme 6. However, Bi(OTf) -
3
mediated tandem annulation of 2a with 3f provided only the
starting material 2a in a 70% yield and unidentified and
complex unknown mixture (∼15%). The desired bridged 5ab
could not be isolated. Next, by changing heteroaromatics from
thiophene (3f) to indole (3g) and pyrrole (3h), the expected 4ao
could not obtained and only starting material 2a was recovered
1
1
X-ray analysis.
With the results in hand, a Bi(OTf)
3
-mediated combination
of 2c and 3c was screened next (Scheme 5). By controlling the
optimal reaction time (10 h), however, the desired 5x was iso-
lated at only a 60% yield along with a non-separated mixture
of acid 4x and ketone 5x-1 (30% yield). In order to increase the
yield, we found that elongating the reaction time to 20 h could
enhance the yield of 5x to 87% (eqn (1)). By the involvement of
(
73% and 68%). Under the standard reaction conditions, these
results were similar. From this phenomenon, we understood
that oxygenated group on 3 could enrich the electron density
of the aromatic ring easily than heteroaromatics 3f–3h.
1
5
,2,3-trimethoxybenzene (3e), treatment of 2f with 3e produced
y at an 89% yield under optimal reaction conditions (eqn (2)).
On the basis of the mentioned conditions, 5z with two
n-propyl arms could be obtained at a 90% yield via Bi(OTf)
mediated tandem annulation of 2m and 3a (eqn (3)). For the
3
-
1
2
n with three methoxy groups (for R ), surprisingly, attempts
to afford the desired 5aa failed due to the steric hindrance of
the C6-methoxy group that inhibited the annulation (eqn (4)).
Scheme 6 Reactions of 2a with 3f.
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INOVA-400 spectrometer operating at 400 and at 100 MHz,
respectively. Chemical shifts (δ) are reported in parts per
million (ppm) and the coupling constants (J) are given in
Hertz. High resolution mass spectra (HRMS) were measured
with a mass spectrometer Finnigan/Thermo Quest MAT 95XL.
X-ray crystal structures were obtained with an Enraf-Nonius
FR-590 diffractometer (CAD4, Kappa CCD).
For the starting substrates arylacetic acids and aldehydes,
these materials were purchased commercially and were used
without further purification.
Scheme 7 Stepwise control experiment.
A representative synthetic procedure of compounds 2a–2m is
as follows
8
Trifluoroacetic anhydride (TFAA, 210 mg, 1.0 mmol) was
added to a solution of arylacetic acids 1 (1.0 mmol) in MeCN
Although substrate 3 was limited to serve as the oxygenated
aryl group, the route still provided a novel and efficient syn-
thesis of the polyoxygenated homotriptycenes skeleton.
To understand the reaction procedure, stepwise control
experiments were performed, as shown in Scheme 7. Initially,
Bi(OTf)3 (30 mol%)-mediated Friedel–Crafts alkylation of 2a
and 3a produced 4a in a 92% yield at 25 °C for 10 h (Table 1,
entry 2) via the lactone ring-opening pathway. With 4a in
hand, the formation of 5a was studied. By using catalytic
(
1
8 mL) at 25 °C. The reaction mixture was stirred at 25 °C for
0 min. Aldehydes (1.0 mmol) in MeCN (2 mL) was added to
the reaction mixture at 25 °C. The reaction mixture was stirred
at 25 °C for 10 h. The solvent of reaction mixture was concen-
trated. The residue was diluted with water (10 mL) and the
mixture was extracted with CH Cl (3 × 20 mL). The combined
2
2
organic layers were washed with brine, dried, filtered and evap-
orated to afford crude product under reduced pressure.
Purification on silica gel (hexanes/EtOAc = 15/1–1/1) afforded
compounds 2a–2m. For the starting compounds 2a–2m, the
general synthetic procedure has been described in our pre-
3
amounts (30 mol%) of Bi(OTf) , 4a was converted to 5a in an
8
6% yield after heating at reflux (101 °C) for 10 h. Compared
with the one-pot process (Table 1, entry 6, 88% yield), the step-
wise two-step route provided a lower total yield of 5a (81%).
The two-step experiments could exhibit that Bi(OTf)3 is an
optimal catalyst to promote the overall reaction procedure
efficiently.
8
vious report.
A representative synthetic procedure of compounds 4a and 5a–
In summary, we have herein developed a combination of Bi 5r, 5r-1–5w-1, 5w-2, 5x–5z is as follows
(
OTf) -promoted facile, air atmosphere, and easy-operational
3
Bi(OTf)
3
(200 mg, 0.3 mmol) was added to a solution of 2
(20 mL) at 25 °C. The reaction mixture
synthesis of polyoxygenated homotriptycenes via inter-
molecular tandem annulation of oxygenated 1-aryl isochro-
man-3-ones with oxygenated arenes in MeNO2 at reflux for
(
1.0 mmol) in MeNO
2
was stirred at 25 °C for 10 min. 3 (1.1 mmol) was added to the
reaction mixture at 25 °C. The reaction mixture was stirred at
reflux (101 °C) for 10 h under an air atmosphere condition.
The reaction mixture was cooled to 25 °C and the solvent was
concentrated. The residue was diluted with water (10 mL) and
1
0 h in good yields. As far as we know, there have been no
reports on the use of Bi(OTf) serving as the catalyst in the for-
3
mation of a substituted tribenzobicyclo[3.2.2]core system. The
Friedel–Crafts type process provides a cascade pathway of three
carbon–carbon bond formations. We have also discussed the
related plausible reaction mechanisms. Further investigations
regarding the metal triflates-mediated synthetic application
will be conducted and published in due course.
2 2
the mixture was extracted with CH Cl (3 × 20 mL). The com-
bined organic layers were washed with brine, dried, filtered
and evaporated to afford crude product under reduced
pressure. Purification on silica gel (hexanes/EtOAc = 8/1–4/1)
afforded compounds 4a and 5a–5r, 5r-1–5w-1, 5w-2, 5x–5z.
{
2-[Bis-(3,4-dimethoxyphenyl)methyl]-4,5-dimethoxyphenyl}
Experimental
acetic acid (4a)
General
In Table 1, entry 6, Yield = 5% (24 mg); Colorless gum; HRMS
+
All reagents and solvents were obtained from commercial (ESI-TOF) m/z: [M + H] calcd for C27
sources and used without further purification. Reactions were 483.2026; H NMR (400 MHz, CDCl ): δ 9.60 (br s, 1H), 6.74 (d,
H
31
O
8
483.2019, found
1
3
routinely carried out under an atmosphere of dry air with mag- J = 8.0 Hz, 1H), 6.73 (s, 2H), 6.63 (d, J = 2.0 Hz, 2H), 6.50 (dd, J
netic stirring. The heating mantle is used to provide a stable = 2.0, 8.4 Hz, 2H), 6.41 (s, 1H), 5.58 (s, 1H), 3.84 (s, 3H), 3.81
1
3
1
heat source. Products in organic solvents were dried with anhy- (s, 6H), 3.70 (s, 6H), 3.60 (s, 3H), 3.53 (s, 2H); C{ H} NMR
drous magnesium sulfate before concentration in vacuo. (100 MHz, CDCl ): δ 177.8, 148.6 (2×), 147.7, 147.3 (2×), 147.1,
Melting points were determined with a SMP3 melting appar- 135.7 (2×), 135.4, 124.1, 121.2 (2×), 113.8, 113.3, 112.5 (2×),
3
1
13
atus. H and C NMR spectra were recorded on a Varian 110.6 (2×), 55.7, 55.6, 55.58 (2×), 55.56 (2×), 51.5, 37.8.
This journal is © The Royal Society of Chemistry 2021
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Paper
,3,7,8,15,16-Hexamethoxy-5,11-dihydro-10H-5,10-[1,2]
Organic & Biomolecular Chemistry
1
3
1
2
16H), 0.88 (t, J = 7.2 Hz, 6H); C{ H} NMR (100 MHz, CDCl
δ 148.0 (2×), 147.8, 147.7, 147.6, 146.8, 135.1, 135.0, 134.5,
34.3, 132.8, 125.7, 115.0, 111.2, 110.9, 108.7, 108.6, 105.9,
3
):
benzenodibenzo[a,d][7]annulen-10-ol (5a)
1
Yield = 88% (408 mg); Colorless solid; mp >250 °C (recrystal-
+
73.9, 69.9, 69.6, 56.2, 56.12, 56.08, 55.8, 53.2, 43.9, 31.8 (2×),
29.4 (2×), 29.34 (2×), 29.27 (2×), 26.0 (2×), 22.6 (2×), 14.1 (2×).
lized from hexanes and EtOAc); HRMS (ESI-TOF) m/z: [M + H]
1
calcd for C27
H
29
O
7
465.1913, found 465.1923; H NMR
(
400 MHz, CDCl
3
): δ 7.29 (s, 2H), 6.89 (s, 2H), 6.81 (s, 1H), 6.39
2
5
,3,7,8,9-Pentamethoxy-15,16-bis(n-octyloxy)-5,11-dihydro-10H-
,10-[1,2]benzenodibenzo[a,d][7]annulen-10-ol (5e)
(s, 1H), 4.60 (s, 1H), 3.91 (s, 3H), 3.872 (s, 6H), 3.871 (s, 6H),
1
3
1
3
(
1
7
.71 (s, 3H), 3.20 (s, 2H), 2.66 (br s, 1H); C{ H} NMR
): δ 147.8 (2×), 147.6 (2×), 146.8, 134.9 (2×),
Yield = 94% (649 mg); Colorless solid; mp = 125–127 °C (recrystal-
lized from hexanes and EtOAc); HRMS (ESI-TOF) m/z: [M + H]
calcd for C H O 691.4210, found 691.4215; H NMR (400 MHz,
100 MHz, CDCl
3
+
34.2 (3×), 132.7, 125.6, 115.0, 110.9, 108.6 (2×), 105.9 (2×),
3.8, 56.2 (2×), 56.11 (2×), 56.07, 55.8, 53.3, 43.9. Single-crystal
1
42 59 8
CDCl
s, 1H), 6.42 (s, 1H), 4.53 (s, 1H), 4.05 (s, 3H), 4.02 (dt, J = 1.2, 6.8
Hz, 2H), 3.97 (t, J = 6.8 Hz, 2H), 3.91 (s, 3H), 3.85 (s, 3H), 3.80 (s,
H), 3.73 (s, 3H), 3.32 (d, J = 16.4 Hz, 1H), 3.25 (d, J = 16.4 Hz,
1H), 1.83–1.74 (m, 4H), 1.46–1.40 (m, 4H), 1.32–1.27 (m, 16H),
3
): δ 7.44 (s, 1H), 6.84 (s, 1H), 6.78 (s, 1H), 6.73 (s, 1H), 6.72
X-Ray diagram: crystal of compound 5a was grown by slow
diffusion of EtOAc into a solution of compound 5a in CH Cl
to yield colorless prisms. The compound crystallizes in the
(
2
2
3
orthorhombic crystal system, space group Pna21, a = 15.2055
3
(18) Å, b = 17.986(2) Å, c = 8.4082(11) Å, V = 2299.5(5) Å , Z = 4,
13
1
calcd = 1.342 g cm− , F(000) = 984, 2θ range 1.754–26.510°, R
3
0.88 (t, J = 7.2 Hz, 6H); C{ H} NMR (100 MHz, CDCl ): δ 152.0,
3
d
150.3, 148.3, 147.8, 147.7, 146.8, 140.4, 138.7, 135.4, 132.5, 132.4,
126.6, 124.9, 114.8, 110.9, 110.8, 109.3, 105.6, 74.5, 69.7, 69.4,
62.1, 60.8, 56.1, 56.0, 55.8, 54.2, 47.0, 31.8 (2×), 29.4 (2×), 29.33
indices (all data) R = 0.1004, wR = 0.1476.
1
2
7
,8,16,17-Tetramethoxy-5,10-dihydro-11H-5,11-[1,2]
benzenobenzo[4′,5′]cyclohepta[1′,2′:4,5]benzo[1,2-d][1,3]dioxol-
1-ol (5b)
Yield = 89% (399 mg); Colorless gum; HRMS (ESI-TOF) m/z: [M 5,10-[1,2]benzenodibenzo[a,d][7]annulen-10-ol (5f)
(2×), 29.25 (2×), 26.0 (2×), 22.6 (2×), 14.1 (2×).
1
15,16-Di-n-butoxy-2,3,7,8,9-pentamethoxy-5,11-dihydro-10H-
+
1
+
25 7
H] calcd for C26H O 449.1600, found 449.1603; H NMR
Yield = 90% (520 mg); Colorless gum; HRMS (ESI-TOF) m/z: [M
+
(
(
(
(
400 MHz, CDCl ): δ 7.28 (s, 1H), 7.24 (s, 1H), 6.88 (s, 1H), 6.83
s, 1H), 6.78 (s, 1H), 6.38 (s, 1H), 5.89 (d, J = 1.2 Hz, 1H), 5.87
d, J = 1.2 Hz, 1H), 4.57 (s, 1H), 3.90 (s, 3H), 3.87 (s, 3H), 3.87
+
1
3
H] calcd for C H O 579.2958, found 579.2962; H NMR
34 43 8
(
3
400 MHz, CDCl ): δ 7.44 (s, 1H), 6.85 (s, 1H), 6.78 (s, 1H),
6
6
3
3
0
.732 (s, 1H), 6.730 (s, 1H), 6.42 (s, 1H), 4.54 (s, 1H), 4.07 (t, J =
.4 Hz, 2H), 4.06 (s, 3H), 3.98 (t, J = 6.8 Hz, 2H), 3.91 (s, 3H),
.85 (s, 3H), 3.80 (s, 3H), 3.73 (s, 3H), 3.33 (d, J = 16.4 Hz, 1H),
.25 (d, J = 16.4 Hz, 1H), 1.82–1.73 (m, 4H), 1.53–1.43 (m, 4H),
.960 (t, J = 7.2 Hz, 3H), 0.955 (t, J = 7.2 Hz, 3H); C{ H} NMR
): δ 152.0, 150.2, 148.2, 147.8, 147.6, 146.8,
1
3
s, 3H), 3.71 (s, 3H), 3.17 (d, J = 2.0 Hz, 2H), 2.60 (br s, 1H);
C
1
{
3
H} NMR (100 MHz, CDCl ): δ 147.82, 147.76, 147.7, 146.8,
1
1
5
46.4, 146.2, 136.6, 135.6, 134.7, 133.9, 132.5, 125.6, 115.0,
10.8, 108.6, 105.9, 105.8, 103.3, 100.9, 74.0, 56.2, 56.1 (2×),
5.8, 53.5, 43.8.
13
1
(
100 MHz, CDCl
3
1
1
5
40.4, 138.7, 135.4, 132.5, 132.3, 126.5, 124.8, 114.7, 110.81,
10.77, 109.3, 105.5, 74.5, 69.4, 69.1, 62.1, 60.8, 56.1, 56.0,
5.8, 54.2, 47.0, 31.39, 31.37, 19.2 (2×), 13.8 (2×).
7
,8-Di-n-butoxy-2,3,15,16-tetramethoxy-5,11-dihydro-10H-5,10-
[1,2]benzenodibenzo[a,d][7]annulen-10-ol (5c)
Yield = 87% (477 mg); Colorless gum; HRMS (ESI-TOF) m/z: [M
+
+
1
H] calcd for C H O 549.2852, found 549.2856; H NMR 17,18-Dimethoxy-5,11-([1,2]benzenomethano)anthra[2,3-d:6,7-
33 41 7
(
(
3
400 MHz, CDCl
s, 1H), 6.38 (s, 1H), 4.57 (s, 1H), 4.00–3.97 (m, 4H), 3.90 (s,
H), 3.86 (s, 3H), 3.84 (s, 3H), 3.70 (s, 3H), 3.20 (s, 2H), 2.77 (br
s, 1H), 1.80–1.71 (m, 4H), 1.53–1.42 (m, 4H), 0.96 (t, J = 7.2 Hz,
3
): δ 7.29 (s, 2H), 6.89 (s, 1H), 6.88 (s, 1H), 6.80 d′]bis([1,3]dioxole)-11(5H)-ol (5g)
Yield = 92% (398 mg); Colorless gum; HRMS (ESI-TOF) m/z: [M
+
1
+
H] calcd for C H O 433.1287, found 433.1295; H NMR
25 21 7
(
400 MHz, CDCl
3
): δ 7.23 (s, 2H), 6.82 (s, 2H), 6.75 (s, 1H), 6.38
1
3
1
3
1
1
6
1
3
H), 0.95 (t, J = 7.6 Hz, 3H); C{ H} NMR (100 MHz, CDCl ): δ
(
s, 1H), 5.90 (d, J = 1.2 Hz, 2H), 5.87 (d, J = 1.2 Hz, 2H), 4.54 (s,
47.9 (2×), 147.7, 147.6, 147.5, 146.7, 135.1, 135.0, 134.5, 134.3,
32.8, 125.7, 115.0, 111.2, 110.8, 108.8, 108.5, 106.0, 73.7, 69.5,
9.3, 56.10, 56.06, 56.0, 55.8, 53.2, 43.9, 31.4 (2×), 19.2, 19.1,
3.8 (2×).
13
1
1
H), 3.89 (s, 3H), 3.71 (s, 3H), 3.14 (s, 2H), 2.49 (s, 1H); C{ H}
): δ 147.8, 146.9, 146.5 (2×), 146.2 (2×),
36.4 (2×), 135.3 (2×), 132.3, 125.5, 114.8, 110.6, 105.8 (2×),
03.3 (2×), 101.0 (2×), 74.1, 56.2, 55.9, 53.7, 43.8.
NMR (100 MHz, CDCl
1
1
3
2
5
,3,7,8-Tetramethoxy-15,16-bis(n-octyloxy)-5,11-dihydro-10H-
,10-[1,2]benzenodibenzo[a,d][7]annulen-10-ol (5d)
7,8,9-Trimethoxy-16,17-bis(n-octyloxy)-5,11-dihydro-10H-5,10-
[1,2]benzenobenzo[4′,5′]cyclohepta[1′,2′:4,5]benzo[1,2-d][1,3]
dioxol-10-ol (5h)
Yield = 90% (594 mg); Colorless gum; HRMS (ESI-TOF) m/z: [M
+
+
1
57 7
H] calcd for C41H O 661.4104, found 661.4115; H NMR Yield = 92% (620 mg); Colorless gum; HRMS (ESI-TOF) m/z: [M
+
1
(400 MHz, CDCl ): δ 7.29 (s, 1H), 7.27 (s, 1H), 6.88 (s, 2H), 6.80 + H] calcd for C H O 675.3897, found 675.3905; H NMR
3
41 55 8
3
(s, 1H), 6.39 (s, 1H), 4.57 (s, 1H), 4.01–3.94 (m, 4H), 3.91 (s, (400 MHz, CDCl ): δ 7.42 (s, 1H), 6.81 (s, 1H), 6.77 (s, 1H), 6.70
3
H), 3.89 (s, 3H), 3.87 (s, 3H), 3.71 (s, 3H), 3.19 (s, 2H), 2.54 (br (s, 2H), 6.39 (s, 1H), 5.82 (s, 2H), 4.51 (s, 1H), 4.05 (s, 3H), 4.04
s, 1H), 1.82–1.75 (m, 4H), 1.46–1.40 (m, 4H), 1.33–1.26 (m, (t, J = 6.8 Hz, 2H), 3.96 (t, J = 6.8 Hz, 2H), 3.84 (s, 3H), 3.80 (s,
4738 | Org. Biomol. Chem., 2021, 19, 4733–4742
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Organic & Biomolecular Chemistry
Paper
3
1
0
1
1
7
2
H), 3.28 (d, J = 16.4 Hz, 1H), 3.21 (d, J = 16.4 Hz, 1H), (400 MHz, CDCl
3
): δ 7.43 (s, 1H), 6.83 (s, 1H), 6.78 (s, 1H), 6.71 (s,
.83–1.75 (m, 4H), 1.49–1.40 (m, 4H), 1.38–1.26 (m, 16H), 1H), 6.70 (s, 1H), 6.40 (s, 1H), 5.82 (s, 2H), 4.51 (s, 1H), 4.05 (s,
1
3
1
3
.90–0.86 (m, 6H); C{ H} NMR (100 MHz, CDCl ): δ 152.1, 3H), 4.05 (t, J = 6.8 Hz, 2H), 3.98 (t, J = 6.4 Hz, 2H), 3.84 (s, 3H),
50.2, 148.2, 147.7, 146.4, 145.4, 140.4, 138.5, 135.3, 133.2, 3.81 (s, 3H), 3.29 (d, J = 16.4 Hz, 1H), 3.22 (d, J = 16.8 Hz, 1H),
32.2, 127.9, 124.8, 111.6, 110.7, 109.2, 107.6, 105.5, 100.8, 1.83–1.74 (m, 4H), 1.54–1.44 (m, 4H), 0.963 (t, J = 7.6 Hz, 3H),
4.4, 69.7, 69.4, 62.2, 60.9, 56.0, 54.4, 47.6, 31.8 (2×), 29.4 (4×), 0.961 (t, J = 7.2 Hz, 3H); C{ H} NMR (100 MHz, CDCl
1
3
1
3
): δ 152.1,
9.3 (2×), 26.0 (2×), 22.6 (2×), 14.1 (2×).
150.2, 148.2, 147.7, 146.4, 145.4, 140.4, 138.5, 135.3, 133.2, 132.3,
1
6
27.9, 124.7, 111.6, 110.7, 109.2, 107.6, 105.5, 100.7, 74.3, 69.3,
9.1, 62.1, 60.8, 56.0, 54.3, 47.6, 31.4 (2×), 19.2 (2×), 13.8 (2×).
7
,8-Di-n-butoxy-16,17-dimethoxy-5,11-dihydro-10H-5,10-[1,2]
benzenobenzo[4′,5′]cyclohepta[1′,2′:4,5]benzo[1,2-d][1,3]dioxol-
0-ol (5i)
Yield = 90% (479 mg); Colorless gum; HRMS (ESI-TOF) m/z: [M
1
7,8,16,17-Tetramethoxy-5,11-dihydro-10H-5,10-[1,2]
benzenobenzo[4′,5′]cyclohepta[1′,2′:4,5]benzo[1,2-d][1,3]dioxol-
10-ol (5m)
+
1
+
37 7
H] calcd for C32H O 533.2539, found 533.2543; H NMR
(
400 MHz, CDCl ): δ 7.28 (s, 1H), 7.27 (s, 1H), 6.863 (s, 1H), Yield = 90% (403 mg); White solid; mp = 220–222 °C (recrystal-
3
+
6
1
3
1
3
1
1
5
.856 (s, 1H), 6.79 (s, 1H), 6.35 (s, 1H), 5.80 (s, 2H), 4.54 (s, lized from hexanes and EtOAc); HRMS (ESI-TOF) m/z: [M + H]
1
25 7
H), 4.01 (dt, J = 2.0, 6.8 Hz, 2H), 3.97 (dt, J = 1.6, 6.4 Hz, 2H), calcd for C26H O 449.1600, found 449.1607; H NMR
.95 (br s, 1H), 3.85 (s, 6H), 3.15 (br s, 2H), 1.80–1.72 (m, 4H), (400 MHz, CDCl ): δ 7.28 (s, 2H), 6.87 (s, 2H), 6.81 (s, 1H), 6.36
3
.52–1.43 (m, 4H), 0.96 (t, J = 7.6 Hz, 3H), 0.95 (t, J = 7.2 Hz, (s, 1H), 5.80 (s, 2H), 4.57 (s, 1H), 3.858 (s, 6H), 3.855 (s, 6H),
13
1
13
1
3 3
H); C{ H} NMR (100 MHz, CDCl ): δ 147.99, 147.96, 147.7, 3.16 (s, 2H), 2.78 (s, 1H); C{ H} NMR (100 MHz, CDCl ): δ
47.6, 146.2, 145.3, 135.0, 134.9, 134.2, 134.0, 133.7, 127.0, 147.7 (2×), 147.6 (2×), 146.3, 145.4, 134.8 (2×), 133.9 (2×),
11.7, 111.1, 108.7, 108.5, 107.7, 105.9, 100.7, 73.6, 69.5, 69.2, 132.5, 126.9, 111.7, 108.5 (2×), 107.7, 105.8 (2×), 100.7, 73.6,
6.1, 56.0, 53.3, 44.6, 31.39, 31.36, 19.2, 19.1, 13.8 (2×).
56.1 (2×), 56.0 (2×), 53.3, 44.5.
2
,3,7,8,9,15,16-Heptamethoxy-5,11-dihydro-10H-5,10-[1,2]
7,8-Dimethoxy-16,17-methylenedioxy-5,11-dihydro-10H-5,10-
[1,2]benzenobenzo[4′,5′]cyclohepta[1′,2′:4,5]benzo[1,2-d][1,3]
dioxol-10-ol (5n)
benzenodibenzo[a,d][7]annulen-10-ol (5j)
Yield = 96% (474 mg); White solid; mp = 196–198 °C (recrystal-
lized from hexanes and EtOAc); HRMS (ESI-TOF) m/z: [M + H]
calcd for C28
+
Yield = 86% (372 mg); White solid; mp = 167–169 °C (recrystal-
1
+
H
31
O
8
495.2019, found 495.2028; H NMR lized from hexanes and EtOAc); HRMS (ESI-TOF) m/z: [M + H]
1
(
(
(
(
400 MHz, CDCl ): δ 7.46 (s, 1H), 6.85 (s, 1H), 6.80 (s, 1H), 6.77 calcd for C H O 433.1287, found 433.1293; H NMR
s, 1H), 6.74 (s, 1H), 6.43 (s, 1H), 4.57 (s, 1H), 4.07 (s, 3H), 3.93 (400 MHz, CDCl
s, 3H), 3.92 (s, 3H), 3.87 (s, 3H), 3.86 (s, 3H), 3.81 (s, 3H), 3.73 (s, 1H), 6.78 (s, 1H), 6.35 (s, 1H), 5.89 (d, J = 1.2 Hz, 1H), 5.87
3
25 21
7
3
): δ 7.26 (s, 1H), 7.22 (s, 1H), 6.86 (s, 1H), 6.80
1
3
s, 3H), 3.3.33 (d, J = 16.4 Hz, 1H), 3.26 (d, J = 16.4 Hz, 1H);
C
(d, J = 1.6 Hz, 1H), 5.81 (d, d = 2.0 Hz, 2H), 4.54 (s, 1H), 3.87 (s,
1
13
1
{
H} NMR (100 MHz, CDCl
46.8, 140.4, 138.6, 135.1, 132.4, 132.1, 126.5, 124.7 (2×), 114.7, (100 MHz, CDCl
10.7, 107.9, 106.8, 105.5, 74.4, 62.1, 60.8, 56.1, 56.03 (2×), 136.5, 135.3, 134.6, 133.8, 133.4, 126.9, 111.7, 108.5, 107.7,
3
): δ 152.0, 150.2, 147.8, 147.4, 3H), 3.86 (s, 3H), 3.13 (s, 2H), 2.60 (s, 1H); C{ H} NMR
1
1
5
3
): δ 147.8, 147.7, 146.44, 146.37, 146.2, 145.5,
6.01, 55.8, 54.2, 46.9.
105.8 (2×), 103.2, 100.9, 100.8, 73.8, 56.2, 56.0, 53.6, 44.5.
7,8,15,16,17-Pentamethoxy-5,10-dihydro-11H-5,11-[1,2]
7,8,9,16,17-Pentamethoxy-5,11-dihydro-10H-5,10-[1,2]
benzenobenzo[4′,5′]cyclohepta[1′,2′:4,5]benzo[1,2-d][1,3]dioxol- benzenobenzo[4′,5′]cyclohepta[1′,2′:4,5]benzo[1,2-d][1,3]dioxol-
1-ol (5k) 10-ol (5o)
Yield = 90% (430 mg); Colorless gum; HRMS (ESI-TOF) m/z: [M Yield = 90% (430 mg); White solid; mp = 214–216 °C (recrystal-
1
+
1
+
+
(
H] calcd for C27
27 8
H O 479.1706, found 479.1715; H NMR lized from hexanes and EtOAc); HRMS (ESI-TOF) m/z: [M + H]
1
400 MHz, CDCl ): δ 7.41 (s, 1H), 6.79 (s, 1H), 6.77 (s, 1H), 6.73 calcd for C27H O 479.1706, found 479.1712; H NMR (400 MHz,
3
27 8
(
s, 1H), 6.72 (s, 1H), 6.42 (s, 1H), 5.89 (d, J = 1.6 Hz, 1H), 5.87 CDCl ): δ 7.46 (s, 1H), 6.84 (s, 1H), 6.81 (s, 1H), 6.75 (s, 1H), 6.73
3
(d, J = 1.6 Hz, 1H), 4.55 (s, 1H), 4.05 (s, 3H), 3.90 (s, 3H), 3.85 (s, 1H), 6.40 (s, 1H), 5.81 (s, 2H), 4.56 (s, 1H), 4.06 (s, 3H), 3.93 (s,
(
s, 3H), 3.81 (s, 3H), 3.73 (s, 3H), 3.31 (d, J = 16.4 Hz, 1H), 3.22 3H), 3.86 (s, 3H), 3.84 (s, 3H), 3.81 (s, 3H), 3.30 (d, J = 16.8 Hz,
13
1
13
1
(d, J = 16.8 Hz, 1H); C{ H} NMR (100 MHz, CDCl ): δ 152.1, 1H), 3.23 (d, J = 16.4 Hz, 1H); C{ H} NMR (100 MHz, CDCl ): δ
3
3
1
1
7
50.2, 147.9, 146.8, 146.5, 146.0, 140.4, 138.3, 136.8, 133.8, 152.0, 150.1, 147.8, 147.4, 146.4, 145.4, 140.3, 138.3, 135.0, 133.0,
32.0, 126.4, 124.6, 114.6, 110.6, 105.5, 105.1, 104.5, 100.8, 132.1, 127.7, 124.5, 111.5, 107.8, 107.5, 106.6, 105.4, 100.7, 74.2,
4.5, 62.2, 60.9, 56.1, 56.0, 55.8, 54.4, 46.9.
62.1, 60.8, 56.0, 55.92, 55.90, 54.2, 47.4.
1
6,17-Di-n-butoxy-7,8,9-trimethoxy-5,11-dihydro-10H-5,10-[1,2]
7,8,16,17-Bis(methylenedioxy)-5,11-dihydro-10H-5,10-[1,2]
benzenobenzo[4′,5′]cyclohepta[1′,2′:4,5]benzo[1,2-d][1,3]dioxol- benzenobenzo[4′,5′]cyclohepta[1′,2′:4,5]benzo[1,2-d][1,3]dioxol-
0-ol (5l) 10-ol (5p)
1
Yield = 89% (500 mg); Colorless gum; HRMS (ESI-TOF) m/z: [M + Yield = 94% (391 mg); Colorless gum; HRMS (ESI-TOF) m/z: [M
+
1
+
1
H] calcd for C H O 563.2645, found 563.2653; H NMR + H] calcd for C H O 417.0974, found 417.0982; H NMR
33
39
8
24 17 7
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1
3
1
(
400 MHz, CDCl
3
): δ 7.21 (s, 2H), 6.78 (s, 2H), 6.75 (s, 1H), 6.34 (s, 3H), 3.75 (s, 3H), 3.43 (d, J = 14.8 Hz, 1H); C{ H} NMR
(
2
(
s, 1H), 5.90 (d, J = 1.2 Hz, 2H), 5.87 (d, J = 1.2 Hz, 2H), 5.82 (s, (100 MHz, CDCl ): δ 193.9, 158.2, 152.6, 148.01, 147.97, 147.4,
3
1
3
1
H), 4.49 (s, 1H), 3.01 (s, 2H), 2.68 (s, 1H); C{ H} NMR 138.7, 134.6, 133.8, 128.1 (2×), 127.1, 125.1, 114.1, 113.9, 113.8,
): δ 146.4 (3×), 146.2 (2×), 145.4, 136.3 (2×), 113.7 (2×), 113.1, 57.3, 56.2, 56.1, 56.0 (2×), 55.2, 49.4.
100 MHz, CDCl
3
1
1
35.0 (2×), 133.2, 126.8, 111.6, 107.6, 105.7 (2×), 103.2 (2×),
00.9 (2×), 100.8, 73.9, 53.8, 44.3.
2
,3,7,8-Tetramethoxy-5-phenyl-5,11-dihydrodibenzo[a,d]
cyclohepten-10-one (5t-1)
1
6,17-Di-n-butoxy-7,8-methylenedioxy-5,11-dihydro-10H-5,10-
Yield = 87% (352 mg); White solid; mp = 207–209 °C (recrystal-
[1,2]benzenobenzo[4′,5′]cyclohepta[1′,2′:4,5]benzo[1,2-d][1,3]
+
lized from hexanes and EtOAc); HRMS (ESI-TOF) m/z: [M + H]
dioxol-10-ol (5q)
1
calcd for C25
H
25
O
5
405.1702, found 405.1712; H NMR
Yield = 89% (459 mg); Colorless gum; HRMS (ESI-TOF) m/z: [M (400 MHz, CDCl ): δ 7.73 (s, 1H), 7.23–7.16 (m, 3H), 7.01 (s,
3
+
1
+
H] calcd for C31
400 MHz, CDCl ): δ 7.25 (s, 1H), 7.22 (s, 1H), 6.85 (s, 1H), 6.79 3.95 (s, 3H), 3.92 (s, 3H), 3.90 (s, 3H), 3.87 (d, J = 14.8 Hz, 1H),
s, 1H), 6.76 (s, 1H), 6.36 (s, 1H), 5.90 (d, J = 1.6 Hz, 1H), 5.88 3.82 (s, 3H), 3.42 (d, J = 14.8 Hz, 1H); C{ H} NMR (100 MHz,
d, J = 1.2 Hz, 1H), 5.81 (s, 2H), 4.50 (s, 1H), 4.01 (t, J = 6.4 Hz, CDCl ): δ 193.7, 152.5, 148.0, 147.9, 147.3, 141.7, 138.2, 134.3,
H), 3.99 (br s, 1H), 3.97 (t, J = 6.4 Hz, 2H), 3.13 (s, 2H), 128.2 (2×), 127.03, 126.96 (2×), 126.4, 125.0, 113.94, 113.86
.80–1.73 (m, 4H), 1.53–1.42 (m, 4H), 0.97 (t, J = 7.2 Hz, 6H); (2×), 113.0, 57.8, 56.0, 55.9, 55.8 (2×), 49.3.
33 7
H O 517.2226, found 517.2231; H NMR 1H), 6.95–6.93 (m, 2H), 6.85 (s, 1H), 6.72 (s, 1H), 5.25 (s, 1H),
(
(
(
3
1
3
1
3
2
1
1
3
1
3
C{ H} NMR (100 MHz, CDCl ): δ 148.1, 146.4, 146.3, 146.2,
2
,3,7,8-Tetramethoxy-5-naphthalen-2-yl-5,11-dihydrodibenzo[a,
d]cyclohepten-10-one (5u-1)
1
1
5
45.5, 136.6, 135.4, 134.8, 134.0, 133.6, 127.0, 125.1, 111.7,
11.1, 108.6, 107.7, 105.8, 103.2, 100.9, 100.8, 73.8, 69.6, 69.3,
3.6, 44.5, 31.5, 31.4, 19.2 (2×), 13.8 (2×).
Yield = 84% (382 mg); White solid; mp = 199–201 °C (recrystal-
lized from hexanes and EtOAc); HRMS (ESI-TOF) m/z: [M + H]
+
2
,3,7,8,16-Pentamethoxy-5,11-dihydro-10H-5,10-[1,2]
benzenodibenzo[a,d][7]annulen-10-ol (5r)
1
calcd for C H O 455.1859, found 455.1863; H NMR
2
9
27 5
(
400 MHz, CDCl
3
): δ 7.80 (s, 1H), 7.79–7.76 (m, 1H), 7.71 (d, J =
Yield = 60% (261 mg); Colorless gum; HRMS (ESI-TOF) m/z: [M 8.8 Hz, 1H), 7.65–7.62 (m, 1H), 7.45–7.40 (m, 2H), 7.30 (s, 1H),
+
1
+
H] calcd for C H O 435.1808, found 435.1816; H NMR 7.15 (dd, J = 1.6, 8.8 Hz, 1H), 7.10 (s, 1H), 6.91 (s, 1H), 6.74 (s,
26 27 6
(
400 MHz, CDCl
3
): δ 7.60 (d, J = 8.4 Hz, 1H), 7.28 (s, 1H), 6.90 1H), 5.40 (s, 1H), 4.00 (s, 3H), 3.98 (s, 3H), 3.97 (s, 3H), 3.94 (d,
1
3
1
(d, J = 2.4 Hz, 1H), 6.89 (s, 1H), 6.81 (s, 1H), 6.76 (dd, J = 2.4, J = 15.2 Hz, 1H), 3.86 (s, 3H), 3.40 (d, J = 14.8 Hz, 1H); C{ H}
8
3
3
.4 Hz, 1H), 6.38 (s, 1H), 5.63 (s, 1H), 3.90 (s, 3H), 3.86 (s, 3H), NMR (100 MHz, CDCl ): δ 193.8, 152.7, 148.1, 147.4, 139.2,
3
.80 (s, 3H), 3.77 (s, 3H), 3.69 (s, 3H), 3.24 (d, J = 16.0 Hz, 1H), 138.2, 134.2, 133.0, 132.0, 128.1, 127.8, 127.4, 127.3, 126.3 (2×),
1
3
1
.17 (d, J = 16.0 Hz, 1H), 2.89 (s, 1H); C{ H} NMR (100 MHz, 125.8, 125.6, 125.4, 125.3, 114.04, 113.99, 113.96, 113.2, 58.2,
CDCl ): δ 158.6, 147.8, 147.7, 147.5, 146.8, 123.0, 135.1, 135.0, 56.2, 56.1, 56.00, 55.96, 49.4.
3
1
1
33.5, 132.2, 125.8, 122.6, 114.9, 111.0, 110.8, 110.7, 108.6,
05.9, 73.6, 56.04, 56.00 (2×), 55.7, 55.2, 53.8, 44.2.
5
-(3,4-Dichlorophenyl)-2,3,7,8-tetramethoxy-5,11-
dihydrodibenzo[a,d]cyclohepten-10-one (5v-1)
2
,3,7,8-Tetramethoxy-5-(3-methoxyphenyl)-5,11-
Yield = 84% (397 mg); Colorless gum; HRMS (ESI-TOF) m/z: [M
dihydrodibenzo[a,d]cyclohepten-10-one (5r-1)
+
1
+
H] calcd for C25
2 5
H23Cl O 473.0923, found 473.0930; H
Yield = 30% (130 mg); White solid; mp = 203–205 °C (recrystal- NMR (400 MHz, CDCl ): δ 7.73 (s, 1H), 7.27 (d, J = 8.4 Hz, 1H),
3
+
lized from hexanes and EtOAc); HRMS (ESI-TOF) m/z: [M + H]
6.99 (dd, J = 1.2, 2.0 Hz, 1H), 6.97 (s, 1H), 6.79 (s, 1H), 6.76
435.1808, found 435.1804; H NMR (ddd, J = 1.2, 2.0, 8.4 Hz, 1H), 6.74 (s, 1H), 5.13 (s, 1H), 3.97 (s,
400 MHz, CDCl ): δ 7.73 (s, 1H), 7.15 (t, J = 8.0 Hz, 1H), 6.98 3H), 3.924 (s, 3H), 3.921 (s, 3H), 3.85 (s, 3H), 3.80 (d, J = 14.8
1
27 6
calcd for C26H O
(
(
3
1
3
1
s, 1H), 6.83 (s, 1H), 6.74 (dd, J = 1.6, 8.0 Hz, 1H), 6.73 (s, 1H), Hz, 1H), 3.46 (d, J = 15.2 Hz, 1H); C{ H} NMR (100 MHz,
6
3
3
.52 (d, J = 7.6 Hz, 1H), 6.48 (s, 1H), 5.19 (s, 1H), 3.98 (s, 3H), CDCl
3
): δ 193.2, 152.7, 148.3 (2×), 147.6, 142.5, 136.9, 133.2,
.94 (s, 3H), 3.94 (d, J = 14.8 Hz, 1H), 3.93 (s, 3H), 3.85 (s, 3H), 132.7, 130.7, 130.1, 129.0, 127.0, 126.5, 124.9, 114.2, 113.8,
1
3
1
.68 (s, 3H), 3.43 (d, J = 14.8 Hz, 1H); C{ H} NMR (100 MHz, 113.7, 113.3, 57.1, 56.1 (2×), 56.0 (2×), 49.4.
): δ 193.9, 159.6, 152.6, 148.1, 148.1, 147.4, 143.7, 138.2,
34.3, 129.3, 127.1, 125.2, 119.7, 114.1, 113.99, 113.96, 113.9,
CDCl
1
1
3
5-(3,4-Difluorophenyl)-2,3,7,8-tetramethoxy-5,11-
dihydrodibenzo[a,d]cyclohepten-10-one (5w-1)
13.1, 110.9, 57.9, 56.2, 56.1, 56.02, 56.00, 55.1, 49.5.
Yield = 80% (352 mg); White solid; mp = 126–128 °C (recrystal-
2
,3,7,8-Tetramethoxy-5-(4-methoxyphenyl)-5,11-
+
lized from hexanes and EtOAc); HRMS (ESI-TOF) m/z: [M + H]
dihydrodibenzo[a,d]cyclohepten-10-one (5s-1)
1
calcd for C25
H
23
F
2
O
5
441.1514, found 441.1517; H NMR
Yield = 80% (347 mg); Colorless gum; HRMS (ESI-TOF) m/z: [M (400 MHz, CDCl
3
): δ 7.71 (s, 1H), 7.01–6.94 (m, 1H), 6.96 (s,
H] calcd for C H O 435.1808, found 435.1814; H NMR 1H), 6.80 (s, 1H), 6.75–6.70 (m, 1H), 6.73 (s, 1H), 6.64–6.61 (m,
+
1
+
2
6
27 6
(
400 MHz, CDCl
3
): δ 7.73 (s, 1H), 6.99 (s, 1H), 6.85 (d, J = 8.0 1H), 5.14 (s, 1H), 3.96 (s, 3H), 3.903 (s, 3H), 3.899 (s, 3H), 3.83
1
3
Hz, 1H), 6.84 (s, 2H), 6.77–6.73 (m, 3H), 5.19 (s, 1H), 3.98 (s, (s, 3H), 3.79 (d, J = 14.8 Hz, 1H), 3.45 (d, J = 15.2 Hz, 1H);
3
C
1
H), 3.94 (s, 3H), 3.929 (s, 3H), 3.931 (d, J = 14.8 Hz, 1H), 3.85 { H} NMR (100 MHz, CDCl ): δ 193.2, 152.7, 150.2 (dd, J = 12.1,
3
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2
1
3
1
47.1 Hz), 148.9 (dd, J = 12.8, 246.3 Hz), 148.3, 148.2, 147.5, 7,8,15,16-Tetramethoxy-2,3-dipropoxy-5,11-dihydro-10H-5,10-
39.2 (t, J = 3.8 Hz), 137.3, 133.4, 126.9, 124.9, 122.9 (dd, J = [1,2]benzenodibenzo[a,d][7]annulen-10-ol (5z)
.8, 6.1 Hz), 116.9 (d, J = 16.7 Hz), 116.2 (d, J = 18.2 Hz), 114.1,
Yield = 90% (468 mg); Colorless gum; HRMS (ESI-TOF) m/z: [M
13.7 (2×), 113.2, 57.0, 56.0 (2×), 55.9 (2×), 49.3.
+
1
+
H] calcd for C H O 521.2539, found 521.2547; H NMR
31 37 7
(
3
400 MHz, CDCl ): δ 7.28 (s, 2H), 6.88 (s, 2H), 6.83 (s, 1H), 6.40
5
-(3,4-Difluorophenyl)-2,3,7,8-tetramethoxy-5H-dibenzo[a,d]
(s, 1H), 4.57 (s, 1H), 3.98 (t, J = 6.4 Hz, 2H), 3.87 (s, 6H), 3.86
(s, 6H), 3.78 (t, J = 6.8 Hz, 2H), 3.18 (s, 2H), 2.65 (br s, 1H),
cycloheptene-10,11-dione (5w-2)
1
.85–1.79 (m, 2H), 1.75–1.69 (m, 2H), 1.03 (t, J = 7.6 Hz, 3H),
Yield = 8% (36 mg); White solid; mp = 238–240 °C (recrystal-
13
1
+
0.95 (t, J = 7.6 Hz, 3H); C{ H} NMR (100 MHz, CDCl
148.1, 147.7 (2×), 147.6 (2×), 147.0, 134.9 (2×), 134.3 (2×),
1
7
3
): δ
lized from hexanes and EtOAc); HRMS (ESI-TOF) m/z: [M + H]
1
calcd for C25
H
21
F
2
O
6
455.1306, found 455.1315; H NMR
32.8, 126.0, 117.8, 114.1, 108.6 (2×), 105.9 (2×), 73.9, 71.4,
0.8, 56.2 (2×), 56.1 (2×), 53.2, 43.8, 22.7, 22.5, 10.5, 10.4.
(400 MHz, CDCl ): δ 7.39 (s, 2H), 6.96 (s, 2H), 6.95–6.89 (m,
3
1
6
1
2
H), 6.53–6.48 (m, 1H), 6.43–6.39 (m, 1H), 5.05 (s, 1H), 4.03 (s,
1
3
1
H), 3.91 (s, 6H); C{ H} NMR (100 MHz, CDCl
53.0 (2×), 150.2 (dd, J = 12.9, 247.9 Hz), 149.0 (dd, J = 13.0,
47.9 Hz), 148.7 (2×), 142.6 (t, J = 3.8 Hz), 138.0 (2×), 127.5 Bi(OTf)3 (200 mg, 0.3 mmol) was added to a solution of 2a
3
): δ 186.0 (2×),
Stepwise synthesis of compound 5a is as follows
(
2×), 123.6 (dd, J = 3.0, 6.0 Hz), 117.2 (d, J = 17.4 Hz), 117.0 (d, (344 mg, 1.0 mmol) in MeNO (20 mL) at 25 °C. The reaction
2
J = 18.2 Hz), 114.8 (2×), 112.2 (2×), 56.6, 56.3 (2×), 56.2 (2×). mixture was stirred at 25 °C for 10 min 3a (152 mg, 1.1 mmol)
Single-crystal X-Ray diagram: crystal of compound 5w-2 was was added to the reaction mixture at 25 °C. The reaction
grown by slow diffusion of EtOAc into a solution of compound mixture was stirred at 25 °C for 10 h under an air atmosphere
5
w-2 in CH Cl to yield colorless prisms. The compound crys- condition, and the solvent was concentrated. The residue was
2 2
tallizes in the monoclinic crystal system, space group P2 /c, a = diluted with water (10 mL) and the mixture was extracted with
1
1
1.9481(8) Å, b = 15.6973(9) Å, c = 12.0408(7) Å, V = 2107.6(2) CH Cl (3 × 20 mL). The combined organic layers were washed
2 2
3
−3
Å , Z = 4, d
= 1.432 g cm , F(000) = 944, 2θ range with brine, dried, filtered and evaporated to afford crude
calcd
1
.826–26.446°, R indices (all data) R = 0.0725, wR = 0.1061.
product under reduced pressure. Purification on silica gel
hexanes/EtOAc = 8/1–4/1) afforded compound 4a (92%,
43 mg). Furthermore, Bi(OTf) (200 mg, 0.3 mmol) was
added to a solution of 4a (482 mg, 1.0 mmol) in MeNO
1
2
(
4
3
1
6,17-Di-n-butoxy-7,8-dimethoxy-5,10-dihydro-11H-5,11-[1,2]
2
benzenobenzo[4′,5′]cyclohepta[1′,2′:4,5]benzo[1,2-d][1,3]dioxol-
1-ol (5x)
(
20 mL) at 25 °C. The reaction mixture was stirred at 25 °C for
1
1
1
0 min. The reaction mixture was stirred at reflux (101 °C) for
0 h under an air atmosphere condition. The reaction mixture
Yield = 87% (463 mg); Colorless gum; HRMS (ESI-TOF) m/z: [M
+
+
1
H] calcd for C H O 533.2539, found 433.2546; H NMR
32 37 7
was cooled to 25 °C and the solvent was concentrated. The
residue was diluted with water (10 mL) and the mixture was
extracted with CH Cl (3 × 20 mL). The combined organic
2 2
layers were washed with brine, dried, filtered and evaporated
to afford crude product under reduced pressure. Purification
on silica gel (hexanes/EtOAc = 8/1–4/1) afforded compound 5a
(
(
(
3
400 MHz, CDCl ): δ 7.27 (s, 1H), 7.24 (s, 1H), 6.88 (s, 1H), 6.82
s, 1H), 6.77 (s, 1H), 6.38 (s, 1H), 6.89 (d, J = 1.6 Hz, 1H), 5.87
d, J = 1.2 Hz, 1H), 4.54 (s, 1H), 4.00 (t, J = 6.4 Hz, 2H), 3.98 (t, J
=
2
6.8 Hz, 2H), 3.90 (s, 3H), 3.72 (s, 3H), 3.16 (br d, J = 0.8 Hz,
H), 2.55 (br s, 1H), 1.80–1.73 (m, 4H), 1.51–1.45 (m, 4H), 0.96
1
3
1
(t, J = 7.6 Hz, 6H); C{ H} NMR (100 MHz, CDCl ): δ 148.1,
3
(
86%, 399 mg).
1
1
7
1
48.0, 147.7, 146.8, 146.4, 146.1, 136.7, 135.7, 135.0, 134.2,
32.6, 125.7, 114.9, 111.2, 110.8, 108.7, 105.8, 103.3, 100.9,
3.9, 69.6, 69.3, 56.1, 55.8, 53.5, 43.9, 31.42, 31.40, 19.2 (2×),
3.8 (2×).
Conflicts of interest
There are no conflicts of interest to declare.
1
6,17-Methylenedioxy-7,8,9-trimethoxy-5,11-dihydro-10H-5,10-
[1,2]benzenobenzo[4′,5′]cyclohepta[1′,2′:4,5]benzo[1,2-d][1,3]
dioxol-10-ol (5y)
Acknowledgements
Yield = 89% (411 mg); Colorless gum; HRMS (ESI-TOF) m/z: [M
+
1
+
H] calcd for C26
400 MHz, CDCl
): δ 7.40 (s, 1H), 6.77 (s, 2H), 6.71 (s, 1H), 6.69 Technology of the Republic of China (Taiwan) for its financial
s, 1H), 6.40 (s, 1H), 5.90 (d, J = 1.2 Hz, 1H), 5.88 (d, J = 1.6 Hz, support (MOST 109-2113-M-037-014-MY3).
23 8
H O
463.1393, found 463.1399; H NMR The authors would like to thank the Ministry of Science and
(
(
3
1
3
H), 5.82 (s, 2H), 4.52 (s, 1H), 4.05 (s, 3H), 3.85 (s, 3H), 3.82 (s,
H), 3.28 (d, J = 16.8 Hz, 1H), 3.19 (d, J = 16.4 Hz, 1H); C{ H}
1
3
1
NMR (100 MHz, CDCl ): δ 152.1, 150.1, 146.51, 146.48, 146.0,
3
Notes and references
1
1
5
45.48, 140.47, 138.1, 136.8, 133.5, 132.9, 127.8, 124.5, 111.5,
07.5, 105.5, 105.1, 104.4, 100.8 (2×), 74.4, 62.2, 60.9, 56.0,
4.5, 47.4.
1 C.-F. Chen and Y.-X. Ma, Synthesis and reactions of tripty-
cenes and their derivatives in Iptycenes Chemistry: From
This journal is © The Royal Society of Chemistry 2021
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Paper
Synthesis to Applications, Springer, Berlin, Heidelberg, 2013,
Organic & Biomolecular Chemistry
3
9 Recent examples on Bi(OTf) -mediated reactions, see:
pp. 13–78.
(a) Y. Gu, W. Huang, S. Chen and X. Wang, Org. Lett., 2018,
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G. Lemière and E. Duñach, Org. Lett., 2015, 17, 1002–1005;
(f) B. C. Raju, K. V. Prasad, G. Saidachary and B. Sridhar,
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Y.-M. Liang, J. Org. Chem., 2017, 82, 1697–1704.
2
Reviews on the synthetic applications on triptycenes, see:
(
(
a) T. R. Kelly, Acc. Chem. Res., 2001, 34, 514–522;
b) L. Zhao, Z. Li and T. Wirth, Chem. Lett., 2010, 39, 658–
6
67.
S. J. Cristol and D. K. Pennelle, J. Org. Chem., 1970, 35,
357–2361.
3
4
5
6
2
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