Fluorinated Phenanthrenes as Aryne Precursors: PAH Synthesis Based on Domino Ring Assembly Using 1,1-Difluoroallenes

Article abstract of DOI:10.1002/asia.202000069

On treatment with the catalyst InBr₃, 1,1-difluoroallenes that bear a cyclopentene moiety and an aryl group underwent domino ring assembly in the presence or absence of N-bromosuccinimide or N-iodosuccinimide to afford aryne precursors such as three-ringed ortho-fluoro(halo)phenanthrenes, four-ringed ortho-fluoro(halo)tetraphenes, ortho-fluoro(halo)chrysenes and fluoro[4]helicenes. Metalation of the aryne precursors followed by elimination of the fluoride resulted in the unprecedented systematic generation of arynes bearing π-extended systems. Diels?Alder reactions of these arynes with isobenzofurans afforded the corresponding cycloadducts whose reductive aromatisation in an SnCl₂/HBr system furnished fully aromatised benzotriphenylenes. In addition, oxidative aryl?aryl coupling (the Scholl reaction) of these benzotriphenylenes facilitated the synthesis of ‘half HBCs’ (hexabenzocoronenes).

Full text of DOI:10.1002/asia.202000069

CHEMISTRY
AN ASIAN JOURNAL
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Accepted Article
Title: Fluorinated Phenanthrenes as Aryne Precursors: PAH Synthesis
Based on Domino Ring Assembly Using 1,1-Difluoroallenes
Authors: Kohei Fuchibe, Masashi Abe, Hiroto Idate, and Junji Ichikawa
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Fluorinated Phenanthrenes as Aryne Precursors: PAH Synthesis
Based on Domino Ring Assembly Using 1,1-Difluoroallenes
Kohei Fuchibe,[a] Masashi Abe, [a] Hiroto Idate, [a] and Junji Ichikawa*[a]
Dedicated to the 100th Annual Meeting of the CSJ
[a]
Dr. K. Fuchibe, M. Abe, H. Idate and Prof. Dr. J. Ichikawa
Division of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba
Tsukuba, Ibaraki 305-8571 (Japan)
E-mail: junji@chem.tsukuba.ac.jp
Supporting information for this article is given via a link at the end of the document.
Abstract: On treatment with the catalyst, InBr3, 1,1-difluoroallenes
that bear a cyclopentene moiety and an aryl group underwent
domino ring assembly in the presence or absence of N-
bromosuccinimide or N-iodosuccinimide to afford aryne precursors
such as three-ringed ortho-fluoro(halo)phenanthrenes, four-ringed
be excellent organic semiconducting materials.[3] Aphenes
possess a bent configuration, which is one of core structures in
PAHs. Known for their zig-zag configuration, phenacenes have
experienced a resurgence in popularity as air-stable organic
semiconductors[4] and their O2-sensing properties are fascinating
to research chemists.[5] Helicenes are optical and electronic
materials[6] with unique chirality-derived characteristics.[7] In
addition to these topologically one-dimensional molecules, both
ortho-fluoro(halo)tetraphenes,
ortho-fluoro(halo)chrysenes
and
fluoro[4]helicenes. Metalation of the aryne precursors followed by
elimination of the fluoride resulted in the unprecedented systematic
generation of arynes bearing π-extended systems. Diels–Alder
reactions of these arynes with isobenzofurans afforded the
corresponding cycloadducts whose reductive aromatisation in an
SnCl2/HBr system furnished fully aromatised benzotriphenylenes. In
addition, oxidative aryl–aryl coupling (the Scholl reaction) of these
benzotriphenylenes facilitated the synthesis of ‘half HBCs’
(hexabenzocoronenes).
triphenylenes
configuration and circulenes, which possess
with
their
topologically
two-dimensional
cyclic
a
configuration, have been used for applications in materials and
supramolecular chemistry,[8] particularly since they both contain
discotic columnar structures in their crystals, which make them
excellent materials for use as liquid crystals, in OFETs and for
the construction of photovoltaic cells.
Arynes have a formal triple bond within their six-membered
ring, thus making them useful tools for the synthesis of fused
benzene ring structures.[9] However, with the exception of
didehydronaphthalenes and didehydrophenanthrenes,[9c] the
synthetic uses of these types of π-extended arynes have been
still limited.[9c,d][10]
One primary shortcoming of π-extended arynes lies in the
preparation of their precursors. In order for arynes to be useful
as starting materials for π-extended PAHs, the synthetic routes
to their respective precursors must facilitate both the
construction of π-systems and the introduction of functional
groups (MG and LG in Figure 2).
Introduction
Polycyclic aromatic hydrocarbons (PAHs), which are a family of
compounds consisting of benzene rings fused in various
configurations,[1] have attracted considerable attention recently
because of their viability as organic electronic materials.[2] With
their linear benzene ring configuration, acenes are one of the
most representative types of PAHs (Figure 1) and are known to
MG
LG
Acenes
(naphthacene)
Aphenes
(tetraphene)
Phenacenes
(chrysene)
Figure 2. π-Extended Arynes and Their Precursors (MG = Metalation Group,
LG = Leaving Group).
Previously, we reported on In-catalysed domino
cyclisation/ring expansion sequences using 1,1-difluoroallenes 1
(Scheme 1).[11,12] Difluoroallenes bearing a cyclopentene moiety
and an aryl group were treated with InBr3 catalyst to generate
the localized difluoroallylic cations in which stabilisation was
achieved by the transfer of a lone pair of electrons from fluorine
to a vacant carbon p orbital (i.e. the α-cation stabilising effect of
fluorine substituents).[13,14] Here, the In-substituted allylic cations
Helicenes
([4]helicene)
Circulenes
(coronene)
Triphenylenes
Figure 1. Major Families of PAHs.
readily underwent
a
regioselective Friedel–Crafts-type
cyclisation followed by ring expansion to afford pinpoint-
1
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fluorinated PAHs 2. Noteworthy is that when the reaction was
performed in the presence of a halogenating agent such as NBS
(N-bromosuccinimide) or NIS (N-iodosuccinimide), the carbon-
indium bond facilitated halogenation, thus affording ortho-
P
P
4 mol% InBr3
X
F
NBS or NIS (1.2 equiv)
fluoro(halo)phenanthrene analogues of
3
that could be
ClCH2CH2Cl, conditions
subsequently transformed into their respective arynes via
dehalogenation.
Q
CF2
Q
1a–c
–
InBr3
2 mol% InBr3
P
+
CF2
[NBS or NIS (1.2 equiv)]
benzo moiey
site P site Q
X
F
DDQ (1.2 equiv)
ClCH2CH2Cl, RT
CF2
–
–
+
–
+
–
1a
1b
1c
reflux
2 h (1a) or 4 h (1b,c)
1
localized allylic cations
Q
(one-pot)
X
F
DDQ (1.2 equiv)
reflux
3a–cX
w/o NBS or NIS 2 (X = H)
w/ NBS or NIS 3 (X = Br or I)
X
F
X
F
X
F
Scheme 1. Domino Cyclisation/Ring Expansion/Halogenation of 1,1-
Difluoroallenes 1.
Thus, we envisioned that the domino cyclisation/ring
expansion/halogenation sequence would open a route to the
systematic synthesis of π-extended arynes. In this paper, the
3aBr, X = Br, 98%
(RT, 3 h)
3bBr, X = Br, 87%
(RT, 4 h)
3cBr, X = Br, 81%
(RT, 5 h)
3aI, X = I, 94%
(RT to 50 °C, 5 h)
3bI, X = I, 85%
(RT to reflux, 4 h)
3cI, X = I, 86%
(RT to 50 °C, 7 h)
synthesis
of
ortho-bromo(fluoro)phenanthrenes,
ortho-
bromo(fluoro)chrysenes and ortho-bromo(fluoro)tetraphenes and
their respective iodo analogues are described. Also discussed
are Diels–Alder reactions of isobenzofurans with the in situ-
generated didehydrophenanthrene, didehydrochrysene and
didehydrotetraphene, two of which were composed of four
benzene rings, as well as their subsequent reductive
aromatisation to the respective benzotriphenylene derivatives.[15]
Furthermore, arynes bearing a [4]helicene framework were
generated from fluorohelicene via dehydrofluorination; this
reaction resulted in the corresponding benzotriphenylenes.
Finally, the most suitable products were subjected to oxidative
aryl–aryl coupling (the Scholl reaction)[16] to facilitate the
synthesis of half hexabenzocoronenes (HBCs).[17]
Scheme 2. Preparation of ortho-Fluoro(halo)arenes 3 (Aryne Precursors).
2 mol% InBr3
DDQ (1.2 equiv)
ClCH2CH2Cl, RT
30 min
reflux, 2 h
(one pot)
CF2
1d
(1)
+
F
F
Results and Discussion
2d, 60%
20%
Preparation of ortho-fluoro(halo)arenes (phenanthrenes,
tetraphenes and chrysenes) and fluoro[4]helicenes. ortho-
Fluoro(halo)phenanthrenes, -tetraphenes and -chrysenes 3 were
prepared via domino ring assembly of 1,1-difluoroallenes
(Scheme 2). First, 1,1-difluoroallenes bearing a cyclopentene
moiety and an aryl group (1a–1c) were prepared from
arylacetonitriles via (i) an initial double allylation for the
construction of the five-membered ring. (ii) A subsequent partial
reduction was carried out, followed by (iii) difluorovinylidenation
of the resulting aldehydes (not shown).[12b] Difluoroallenes,
including 1b and 1c, with an additional benzo moiety on either
the P or Q site (Scheme 2) were treated with 4 mol% of InBr3 in
the presence of NBS (1.2 equiv) or NIS (1.2 equiv) followed by a
one-pot dehydrogenation using DDQ. Domino cyclisation/ring
expansion/halogenation (via bromination or iodination) afforded
the desired ortho-fluoro(halo)phenanthrenes 3aBr (98% yield)
and 3aI (94% yield), fluoro(halo)tetraphenes 3bBr (87% yield)
and 3bI (85% yield) and, lastly, fluoro(halo)chrysenes 3cBr
(81% yield) and 3cI (86% yield). Fluoro[4]helicene, 2d, was
prepared as shown in Eq 1.[18]
Generation of Arynes A–D and Their Diels–Alder Reactions.
To construct the benzene rings, the arynes underwent Diels–
Alder reactions using isobenzofurans as the dienes. The
isobenzofurans 4a–f (Figure 3) were easily prepared from
commercially available methyl o-formylbenzoate and the
corresponding arylmagnesium bromides (2.3 equiv) via the
method reported by Hamura.[19]
2
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didehydrochrysene C (Figure 4) to afford the oxygenated
benzotriphenylene analogues 5ba and 5ca in 88% and 94%
yields, respectively (Eqs 2 and 3).
Ar
Ar
4a
4b
4c
Ph
4d
4e
4f
C6H4p-t-Bu
C6H4p-F
O
C6H4p-OMe
C6H4p-n-Hex
2-Thienyl
Ar
Ar
Ar
Br
n-BuLi (1.2 equiv)
Figure 3. Analogues of Isobenzofurans 4.
O
+
O
Et2O–THF (4:1)
RT, 2 h
F
Ar
Ar
In the presence of isobenzofuran 4a, bromo(fluoro)phenan-
threne 3aBr was treated with butyllithium (1.2 equiv) at −90°C,
which allowed for Li–Br exchange to take place followed by LiF
elimination to generate the desired aryne.[20] After warming to RT,
the adduct 5aa was obtained in 55% yield along with
fluorophenanthrene 2a in 24% yield (Entry 1, Table 1). Thus, it
was clear that the intermediate 13,14-didehydrophenanthrene
(phenanthryne) (A) was generated to undergo Diels–Alder
reaction with 4a. Deuterium labelling experiments (D2O quench)
performed under identical reaction conditions indicated that no
deuterium had been incorporated into the structure of 2a (as
determined by 1H NMR). This meant that protonation was a
competitive process in the reaction medium, especially in the
presence of THF.
via A
3aBr
4 (2.0 equiv)
5
Table 2. Diels–Alder Reaction between Phenanthryne A and Isobenzofurans
4.
Entry
4
Ar
5
Yield [%]
1
2
3
4
5
6
4a
4b
4c
4d
4e
4f
Ph
5aa
5ab
5ac
5ad
5ae
5af
89
81
82
81
80
67
C6H4p-OMe
C6H4p-n-Hex
C6H4p-t-Bu
C6H4p-F
2-Thienyl
Ph
Br
n-BuLi (1.2 equiv)
O
+
Et2O–THF (4:1), 2 h
– LiBr, – LiF
F
Ph
n-BuLi
Ph
(1.2 equiv)
Br
F
3aBr
4a
phenanthryne A
(2)
4a (2.0 equiv)
Et2O–THF (4:1)
RT, 4 h
O
Ph
Ph
H
F
via B
+
O
3bBr
5ba, 88%
Ph
Ph
Br
n-BuLi
5aa
2a
(1.2 equiv)
O
(3)
F
4a (2.0 equiv)
Et2O–THF (4:1)
RT, 3 h
Ph
Table 1. Generation and Diels–Alder Reaction of Aryne A.
Entry
4a [equiv]
1.2
Temperature
–90 °C to RT
RT
5aa [%][a]
2a [%][a]
via C
3cBr
5ca, 94%
1
2
3
55
66
84
24
9
1.2
2.0
RT
8
[a] 1H NMR yield based on an internal standard CH2Br2.
In order to boost the elimination of lithium fluoride from the
intermediary fluoro(lithio)phenanthrene, the reaction was
performed at room temperature (Entry 2). Here, the 5aa/2a ratio
increased significantly, and 5aa was obtained in 66% yield. By
using 2.0 equiv of 4a, the yield of 5aa was improved to 84%
5,6-didehydro-
5,6-didehydro-
chrysene C
5,6-didehydro-
[4]helicene D
tetraphene B
Figure 4. Generated π-Extended Arynes B–D.
(Entry 3). Diels–Alder reactions of
3 with several other
Although deprotonation of fluorohelicene 2d with
butyllithium afforded the Diels–Alder adduct 5da in low yield
(56%), the use of Me2(TMP)ZnLi dramatically improved the yield
of 5da (Scheme 3).[21] Treatment of 2d with Me2(TMP)ZnLi (4.0
equiv) in the presence of 4a (THF, reflux, 1.5 h) afforded 5da in
93% yield.
isobenzofurans were conducted under the aforementioned
conditions (Table 2). Phenanthryne A underwent Diels–Alder
reaction to afford the desired adducts 5aa–5af in 67%–89%
yields. Similar reactions were also conducted using π-extended
3bBr and 3cBr with 4a in which the reactions proceeded via the
intermediates
5,6-didehydrotetraphene
B
and
5,6-
3
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–
afford 6ab in 76% yield and 7ab in 11% yield (Entry 4, Table 3).
In contrast, using an ether solution of HCl decreased product
selectivity to afford 6ab in 37% yield and 7ab in 57% yield (Entry
5). The type of counter anions for the acid also decisively
affected product selectivity; this could be best seen in the cases
of HBr and HI. Whereas HBr afforded 6ab and 7ab in 98% and
Me2(TMP)ZnLi
ZnMe2
F
(2.2 equiv)
Li+
4a (2.0 equiv)
F
THF, reflux, 6 h
2d
Ar
O
Ph
Sn(II)
O
5aa or 5ab
+
via D
Ar Ar
Ph
Ar
6aa, Ar = Ph
6ab, Ar = C6H4p-OMe
7aa, Ar = Ph
7ab, Ar = C6H4p-OMe
5da, 93%
Scheme 3. Diels–Alder Reaction of Didehydrohelicene D and Isobenzofurans
4 (TMP = tetramethylpiperidino).
Table 3. Reductive Aromatisation of 5 Under Acidic Conditions.
Yield [%][a]
Entry
5
Reagents and Conditions
Reductive Aromatisation of the Diels–Alder Adducts 5.
Reductive aromatisation of the adduct 5aa to benzotriphenylene
6aa proceeded under basic conditions (Scheme 4). Low-valent
titanium species generated from TiCl3 and butyllithium promoted
aromatisation to afford 6aa in 92% yield. The low-valent titanium
species were also generated from Cp2TiCl2/butyllithium and from
TiCl4/Zn, both of which afforded 6aa in 90% and 72% yields,
respectively. Although successful with 5aa, aromatisation using
the latter two reagent systems was ineffective when applied to
other π-extended analogues of 5, whereas the former two
reagent systems were strongly basic. Thus, further examination
was carried out.
6
7
SnCl2 (10 equiv), HCl (20 equiv)
Et2O, RT, overnight
1
2
3
4
5
6
7
5aa
5aa
5ab
5ab
5ab
5ab
5ab
49, 6aa
–
SnCl2 (5 equiv), HCl (10 equiv)
THF, reflux, 9 h
(81), 6aa
(52), 6ab
76, 6ab
37, 6ab
(98), 6ab
97, 6ab
–
SnCl2 (5 equiv), HCl (10 equiv)
THF, 60 °C, 5 h
(45), 7ab
11, 7ab
57, 7ab
2, 7ab
–
SnCl2 (5 equiv), HCl (10 equiv in
MeOH), THF, 60 °C, 5 h
SnCl2 (5 equiv), HCl (10 equiv
in E2O), THF, 60 °C, 5 h
Ph
Ph
SnCl2 (5 equiv), HBr (10 equiv)
THF, 60 °C, 5 h
O
Ph
Ph
SnCl2 (5 equiv), HI (10 equiv)
THF, 60 °C, 5 h
5aa
6aa
[a] 1H NMR yield based on an internal standard CH2Br2 (isolated yield in
parentheses).
TiCl3 (15 equiv), n-BuLi (30 equiv)
92%
90%
72%
Et2O, RT, 4 h
H+ (HX)
HO Ar
Cp2TiCl2 (5 equiv), n-BuLi (10 equiv)
5ab
THF, RT, 1 h
+
TiCl4 (15 equiv), Zn (30 equiv)
THF, RT, 12 h
Ar
Scheme 4. Reductive Aromatisation of 5 Under Basic Conditions (1H NMR
yield based on an internal standard CH2Br2).
8ab, Ar = C6H4p-OMe
+
OH
Next, reductive aromatisation under acidic conditions was
examined with commercially available tin(II) chloride (Table 3).
Using SnCl2 (10 equiv)/HCl (20 equiv) afforded 6aa in 49% yield
(Entry 1); however, decreasing the amounts of reagents raised
the yield to 81% (Entry 2). The p-methoxy-bearing substrate 5ab
afforded 6ab in 52% yield along with the migration product 7ab
in 45% yield (Entry 3). As shown in Scheme 5, the protonation of
5ab generated the carbocation intermediate 8ab. Thus, it was
rationalized that the use of a group, such as a p-methoxyphenyl
group, that is more nucleophilic than the phenyl group, caused
1,4-migration and led to the formation of 7ab (Path a).
path a
7ab
Ar Ar
HO Ar
path b
6ab
Ar
X
9ab
Nucleophilic components, such as alcohols and the counter
anions of acids, also affected product selectivity (6ab/7ab). The
use of a methanol solution of HCl increased the selectivity to
Scheme 5. A Plausible Mechanism for the Formation of Benzotriphenylene
6ab and Ketone 7ab.
4
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2% yields, respectively (Entry 6), HI afforded 6ab as the sole
product (97% yield, Entry 7). The effect of nucleophilic
components (methanol in Entry 4, a bromide ion in Entry 6 and
an iodide ion in Entry 7) is rationalised through their attack on
the carbocation intermediate 8ab, which suppresses
rearrangement to 7ab (Path a, Scheme 5). Thus, the generation
of intermediate 9ab is promoted and, ultimately, the formation of
the desired benzotriphenylene 6ab (Path b).
acidic conditions to afford the benzotriphenylenes 6aa–af in
62%–99% yields. The cycloadducts 5ba, 5ca and 5da, which
possessed
a
tetraphene,
a
chrysene and
a
helicene
substructure also gave 6ba, 6ca and 6da in 65%, 87% and 86%
yields, respectively (Scheme 6). Thus, the generation of π-
extended arynes based on domino ring assembly of 1,1-
difluoroallenes
has
facilitated
systematic
entry
to
benzotriphenylenes with structural diversity.
Using the optimised conditions, various benzotriphenylene
analogues were synthesised (Table 4). The Diels–Alder adducts,
5aa–af, which had aryl groups with a functionality and thienyl
groups were successfully aromatised using the aforementioned
Intramolecular Ary–Aryl Coupling of Benzotriphenylenes 6.
Dehydrogenative coupling of the aromatic compounds (the
Scholl reaction) is a powerful method for expanding π-systems.
Since the synthesised diaryltriphenylenes 6 were structurally
suitable for the Scholl reaction, we investigated the π extension
Ar
Ar
SnCl2 (5 equiv)
HBr (10 equiv)
of
6
to facilitate the synthesis of ‘half HBCs’
(hexabenzocoronenes). Thus, the triphenylene 6aa was treated
with excess iron(III) chloride in 1,2-dichloroethane–nitromethane
(5:1) at 0°C. The desired product 10aa (‘half HBC’) was
obtained in 84% yield (Scheme 7). Primary and tertiary alkyl-
bearing 6ac and 6ad underwent similar dehydrogenative
coupling to give 10ac and 10ad in 98% and 94% yields,
respectively.[22]
O
THF, 60 °C
Ar
Ar
5
6
Table 4. Synthesis of Benzotriphenylenes 6 (1).
Entry
1[a]
2[b]
3
Ar
5
t [h]
10
5
6
Yield [%]
R
R
Ph
5aa
5ab
5ac
5ad
5ae
5af
6aa
6ab
6ac
6ad
6ae
6af
93
98
98
99
86
62
C6H4p-OMe
C6H4p-n-Hex
C6H4p-t-Bu
C6H4p-F
2-Thienyl
FeCl3 (30 equiv)
3
ClCH2CH2Cl–MeNO2
(5:1)
4
12
6
5
6[c]
9
R
R
10aa, 84%, 1 h
10ac, 98%, 1 h
10ad, 94%, 0.5 h
6aa (R = H)
6ac (R = n-Hex)
6ad (R = t-Bu)
[a] SnCl2 (15 equiv) and HBr (30 equiv). [b] Table 3, Entry 6. [c] SnCl2 (5
equiv) and HCl (10 equiv).
Scheme 7. Synthesis of ‘Half HBCs’ 10.
SnCl2 (5 equiv)
Ph
Ph
HBr (10 equiv)
THF, 60 °C, 26 h
O
Conclusion
Ph
Ph
Using ortho-fluoro(halo)arenes (such as phenanthrenes,
tetraphenes and chrysenes) and fluorohelicenes,
5ba
6ba, 65%
benzotriphenylenes were synthesised via π-extended aryne
intermediates. These aryne precursors were prepared through
Ph
Ph
SnCl2 (15 equiv)
HBr (30 equiv)
domino ring assembly of 1,1-difluoroallenes bearing
a
O
cyclopentene moiety and an aryl group; this reaction was
initiated on treatment with the InBr3 catalyst in the presence or
absence of NBS or NIS. Metalation (n-BuLi or Me2TMPZnLi) of
the precursors and the subsequent elimination of a fluoride ion
generated the corresponding arynes. This is an unprecedented
means for the systematic generation of π-extended arynes and
may prove beneficial in accessing synthetic routes to higher-
order PAHs. Diels–Alder reactions with isobenzofurans afforded
cycloadducts whose reductive aromatisation in an SnCl2/HBr
system furnished the fully aromatised benzotriphenylene
analogues. In addition, further dehydrogenative aryl–aryl
coupling (the Scholl reaction) provided a facile entry to ‘half
HBC’ analogues.
THF, 60 °C, 12 h
Ph
Ph
5ca
6ca, 87%
Ph
Ph
SnCl2 (10 equiv)
HBr (20 equiv)
O
THF, 60 °C, 24 h
Ph
Ph
6da, 86%
5da
Scheme 6. Synthesis of Benzotriphenylenes 6 (2).
5
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1.6 Hz, 1H), 8.67–8.72 (m, 2H), 9.17 (d, J = 8.6 Hz, 1H); 13C NMR (126
MHz, CDCl3): δ = 85.3 (d, J = 29 Hz), 119.5 (d, J = 15 Hz), 120.7 (d, J = 3
Hz), 123.5 (d, J = 2 Hz), 126.5 (d, J = 3 Hz), 127.0 (d, J = 2 Hz), 127.6 (d,
J = 3 Hz), 128.07 (d, J = 3 Hz), 128.09 (d, J = 10 Hz), 128.5 (d, J = 8 Hz),
131.3 (d, J = 6 Hz), 132.2 (d, J = 6 Hz), 132.7 (d, J = 5 Hz), 158.9 (d, J =
251 Hz), 127.7, 127.9, 129.8, 132.8; 19F NMR (470 MHz, CDCl3): δ =
83.4 (s); IR (neat): ν~ 3057, 1581, 1427, 1238, 816, 756 cm–1; Anal. calcd.
for C18H10FI: C, 58.09; H, 2.71; found: C, 57.84; H, 2.72.
Experimental Section
THF, diethyl ether and DMF were dried by passing through a column of
activated alumina followed by a column of Q-5 scavenger (Engelhard).
1,2-Dichloroethane and nitromethane were distilled from CaH2 and
stored under MS 4A. Me2Zn (a heptane solution), TiCl4, SnCl2 and FeCl3
were purchased from Merck KGaA and used as received. Cp2TiCl2 and
conc. HBr were purchased from TOKYO CHEMICAL INDUSTRY CO.,
LTD. and used as received. TiCl3 and conc. HCl were purchased from
Kishida Chemical Co., Ltd. and used as received.
Generation and Diels–Alder reaction of arynes (from ortho-
fluoro(halo)arenes). Synthesis of adduct 5aa is described as a typical
Column chromatography was conducted on silica gel (Silica Gel 60
N, Kanto Chemical Co., Inc. for column chromatography). Purification
was also performed by preparative HPLC (GPC), using a JAI LC-908
instrument (Jaigel-2H, CHCl3).
procedure. To
a
mixed ether–THF solution (4:1,
4
mL) of
bromo(fluoro)phenanthrene 3aBr (36 mg, 0.13 mmol) and isobenzofuran
4a (70 mg, 0.26 mmol) was added a hexane solution of butyllithium (1.6
mol/L, 0.10 mL, 0.16 mmol) at room temperature. The resulting solution
was stirred for 2 h. Saturated. aq. NH4Cl was added to quench the
reaction and organic materials were extracted with ethyl acetate three
times. The combined extracts were washed with brine and dried over
anhydrous Na2SO4. After removal of the solvent under reduced pressure,
the residue was purified by column chromatography on silica gel
(hexane/ethyl acetate 20:1) to give adduct 5aa (52 mg, 89% yield) as a
colorless solid.
IR spectra were recorded on a Horiba FT-300S spectrometer by the
attenuated total reflectance (ATR method). NMR spectra were recorded
on Bruker Avance 500 or Jeol JNM ECS-400 spectrometers in CDCl3 at
500 or 400 MHz (1H NMR), at 126 or 101 MHz (13C NMR), and at 470 or
376 MHz (19F NMR). Chemical shifts were given in ppm relative to
internal Me4Si (for 1H NMR: δ = 0.00), CDCl3 (for 13C NMR: δ = 77.0) and
C6F6 (for 19F NMR: δ = 0.0; C6F6 exhibits a 19F NMR signal at –162.9 ppm
vs. CFCl3). High-resolution mass spectroscopy (HRMS) was conducted
with Jeol JMS-T100GCV (EI/TOF) and Jeol JMS-T100CS (ESI+/TOF or
APCI+/TOF) spectrometers. Elemental analyses (EA) were performed
with a Yanako MT-3 CHN Corder apparatus.
9,14-Dihydro-9,14-diphenyl-9,14-epoxybenzo[b]triphenylene
5aa: 1H
NMR: δ = 6.95–7.00 (m, 2H), 7.32 (dd, J = 7.5, 7.5 Hz, 2H), 7.45–7.55 (m,
8H), 7.62 (d, J = 8.0 Hz, 2H), 7.63–7.67 (m, 2H), 8.05 (br d, J = 5.0 Hz,
4H), 8.62 (d, J = 8.0 Hz, 2H); 13C NMR: δ = 93.2, 122.0, 123.5, 124.5,
125.2, 126.1, 126.2, 127.2, 128.8, 129.4 130.2, 130.4, 135.1, 148.5,
151.2; IR (neat): ν 3064, 1456, 1218, 771, 752 cm–1; HRMS (APCI+):
calcd. for C34H23O [M+H]+: 447.1749; found: 447.1750.
Isobenzofurans
4
were prepared by the reported method.[19a]
Preparation and spectral data of ortho-fluoro(halo)phenanthrenes (3aBr
and 3aI) were described in the previous paper.[11a] Ortho-
fluoro(halo)tetraphenes (3bBr and 3bI) and ortho-fluoro(halo)chrysenes
(3cBr and 3cI) were prepared by the same method. Preparation and
∼
9,14-Dihydro-9,14-di(4-methoxyphenyl)-9,14-epoxybenzo[b]triphenylene
5ab: 1H NMR (500 MHz, CDCl3): δ = 3.88 (s, 6H), 6.96–6.97 (m, 2H),
7.04 (dd, J = 7.7, 1.3 Hz, 4H), 7.37 (ddd, J = 8.3, 7.1, 1.0 Hz, 2H), 7.54
(ddd, J = 8.4, 7.1, 1.3 Hz, 2H), 7.59–7.63 (m, 2H), 7.68 (dd, J = 8.3, 1.0
Hz, 2H), 7.96 (br d, J = 6.5 Hz, 4H), 8.68 (d, J = 8.4 Hz, 2H); 13C NMR
(126 MHz, CDCl3): δ = 55.4, 92.6, 114.1, 121.9, 123.5, 124.5, 125.1,
126.05, 126.12, 127.2, 127.3, 130.4, 131.7 (br), 148.5, 151.5, 160.3; IR
(neat): ν~ 2837, 1516, 1248, 1176, 904, 723 cm–1; HRMS (APCI+): calcd.
for C36H27O3 [M+H]+: 507.1960; found: 507.1957.
spectral data of fluorohelicene 2d were described in the previous paper.
[11a]
6-Bromo-5-fluorobenzo[a]anthracene 3bBr: 1H NMR (500 MHz, CDCl3): δ
= 7.53–7.60 (m, 2H), 7.64 (dd, J = 7.5, 7.5 Hz, 1H), 7.71 (ddd, J = 7.5,
7.5, 1.3 Hz, 1H), 8.01–8.06 (m, 2H), 8.07 (dd, J = 8.0, 0.5 Hz, 1H), 8.67
(s, 1H), 8.68 (d, J = 7.5 Hz, 1H), 8.97 (s, 1H); 13C NMR (126 MHz,
CDCl3): δ = 103.9 (d, JCF = 21 Hz), 121.2 (d, JCF = 6 Hz), 121.8 (d, JCF
=
1 Hz), 122.8 (d, JCF = 3 Hz), 124.1 (d, JCF = 21 Hz), 126.1 (d, JCF = 8 Hz),
126.2, 126.4, 126.5, 127.5, 127.8, 128.0, 128.0, 128.2, 130.7 (d, JCF = 6
Hz), 131.2 (d, JCF = 1 Hz), 132.2, 153.9 (d, JCF = 252 Hz); 19F NMR (470
MHz, CDCl3): δ = 50.2 (s); IR (neat): ν~ =2960, 1358, 1219, 876, 771,
744 cm–1; HRMS (EI): calcd. for C18H10BrF [M]+: 323.9950; found:
323.9951.
9,14-Di(4-hexylphenyl)-9,14-dihydro-9,14-epoxybenzo[b]triphenylene
5ac: 1H NMR (500 MHz, CDCl3): δ = 0.88 (t, J = 7.0 Hz, 6H), 1.25–1.39
(m, 12H), 1.64 (tt, J = 7.5, 7.5 Hz, 2H), 1.65 (tt, J = 7.5, 7.5 Hz, 2H), 2.69
(t, J = 7.5 Hz, 4H), 6.96–6.99 (m, 2H), 7.32 (d, J = 8.5 Hz, 4H), 7.35 (ddd,
J = 8.3, 7.1, 1.1 Hz, 2H), 7.53 (ddd, J = 8.3, 7.1, 1.3 Hz, 2H), 7.60–7.64
(m, 2H), 7.68 (dd, J = 8.3, 1.0 Hz, 2H), 7.94 (br d, J = 6.7 Hz, 4H), 8.67
(d, J = 8.4 Hz, 2H); 13C NMR (126 MHz, CDCl3): δ = 14.1, 22.6, 28.9,
31.3, 31.7, 35.8, 93.0, 122.0, 123.4, 124.6, 125.1, 126.0, 126.1, 127.3,
128.8, 130.2 (br s), 130.4, 132.3, 144.2, 148.6, 151.5; IR (neat): ν~
2925, 2856, 993, 746, 723 cm–1; HRMS (APCI+): calcd. for C46H47
[M+H]+: 615.3627; found: 615.3632.
5-Fluoro-6-iodobenzo[a]anthracene 3bI: 1H NMR (500 MHz, CDCl3): δ =
7.57–7.66 (m, 2H), 7.68 (dd, J = 7.6, 7.6 Hz, 1H), 7.78 (dd, J = 7.6, 7.6
Hz, 1H), 8.09–8.14 (m, 3H), 8.69 (s, 1H), 8.79 (d, J = 8.4 Hz, 1H), 9.06 (s,
1H); 13C NMR (126 MHz, CDCl3): δ = 81.4 (d, JCF = 26 Hz), 121.5 (d, JCF
= 6 Hz), 122.0 (d, JCF = 1 Hz), 123.0 (d, JCF = 4 Hz), 124.0 (d, JCF = 22
Hz), 129.9 (d, JCF = 4 Hz), 131.2 (d, JCF = 8 Hz), 131.6 (d, JCF = 2 Hz),
131.7 (d, JCF = 6 Hz), 157.5 (d, JCF = 250 Hz), 126.3, 126.5, 126.6, 127.5,
127.8, 128.0, 128.6, 132.7; 19F NMR (470 MHz, CDCl3): δ = 68.9 (s). IR
(neat): ν~ = 3055, 1616, 1495, 1356, 876, 771 cm–1; Anal. calcd. for
C18H10FI: C, 58.09; H, 2.71; found: C, 57.67; H, 2.55.
=
O
9,14-Di(4-tert-butylphenyl)-9,14-dihydro-9,14-epoxybenzo[b]triphenylene
5ad: 1H NMR (500 MHz, CDCl3): δ = 1.36 (s, 18H), 6.96–6.97 (m, 2H),
7.38 (ddd, J = 8.3, 7.1, 1.1 Hz, 2H), 7.48–7.56 (m, 6H), 7.58–7.64 (m,
2H), 7.75 (d, J = 8.3 Hz, 2H), 7.95 (br d, J = 6.5 Hz, 4H), 8.68 (d, J = 8.4
Hz, 2H); 13C NMR (126 MHz, CDCl3): δ = 31.4, 34.8, 93.0, 121.9, 123.5,
124.7, 125.0, 125.6, 126.0, 126.1, 127.4, 130.0 (br s), 130.5, 132.1,
6-Bromo-5-fluorochrysene 3cBr: 1H NMR (500 MHz, CDCl3): δ = 7.62–7.73
(m, 4H), 7.96 (dd, J = 8.0, 1.5 Hz, 1H), 8.00 (d, J = 9.0 Hz, 1H), 8.37 (dd,
J = 8.5, 1.0 Hz, 1H), 8.60 (dd, J = 9.5, 2.5 Hz, 1H), 8.68 (d, J = 8.0 Hz,
1H), 9.13 (br d, J = 8.5 Hz, 1H); 13C NMR (126 MHz, CDCl3): δ = 107.3 (d,
148.6, 151.6, 152.4; IR (neat): ν~ = 2962, 1269, 906, 750, 723 cm–1
;
HRMS (APCI+): calcd. for C42H39O [M+H]+: 559.3001; found: 559.3000.
9,14-Di(4-fluorophenyl)-9,14-dihydro-9,14-epoxybenzo[b]triphenylene
JCF = 19 Hz), 119.6 (d, JCF = 13 Hz), 120.5 (d, JCF = 3 Hz), 123.3 (d, JCF
=
5ae: 1H NMR (500 MHz, CDCl3): δ = 6.93–6.97 (m, 2H), 7.20 (dd, J = 8.8,
8.8 Hz, 4H), 7.35 (ddd, J = 8.0, 7.0, 1.0 Hz, 2H), 7.50 (ddd, J = 8.4, 7.0,
1.5 Hz, 2H), 7.55–7.61 (m, 4H), 8.02 (br s, 4H), 8.61 (d, J = 8.4 Hz, 2H);
13C NMR (126 MHz, CDCl3): δ = 92.5, 115.8 (d, JCF = 22 Hz), 121.9,
123.6, 124.2, 125.4, 126.2, 126.4, 127.0, 130.5, 130.9 (d, JCF = 2 Hz),
132.2 (br), 148.1, 150.9, 163.4 (d, JCF = 249 Hz); 19F NMR (470 MHz,
CDCl3): δ = 49.9–50.0 (m); IR (neat): ν~ = 1512, 1227, 833, 750, 725 cm–
2 Hz), 126.4 (d, JCF = 2 Hz), 126.9 (d, JCF = 2 Hz), 127.0 (d, JCF = 7 Hz),
127.5 (d, JCF = 2 Hz), 127.5 (d, JCF = 28 Hz), 127.96, 128.02, 128.1 (d,
JCF = 6 Hz), 128.5, 129.4, 130.1 (d, JCF = 6 Hz), 130.5 (d, JCF = 3 Hz),
132.7, 156.1 (d, JCF = 253 Hz); 19F NMR (470 MHz, CDCl3): δ = 63.5 (s);
IR (neat): ν~ 3051, 1589, 1431, 1238, 912, 746 cm–1; HRMS (EI): calcd.
for C18H10BrF [M]+: 323.9950; found: 323.9946.
5-Fluoro-6-iodochrysene 3cI: 1H NMR (500 MHz, CDCl3): δ = 7.64–7.77 (m,
4H), 7.99 (d, J = 7.9 Hz, 1H), 8.06 (d, J = 9.1 Hz, 1H), 8.33 (dd, J = 7.9,
6
This article is protected by copyright. All rights reserved.

10.1002/asia.202000069
Chemistry - An Asian Journal
FULL PAPER
1
;
HRMS (APCI+): Calcd. for C34H21F2O [M+H]+: 483.1561; found:
removal of the solvent under reduced pressure, the silica gel was
483.1564.
charged to a small pad of SiO2 and purification by column
chromatography (hexane/ethyl acetate 10:1) gave benzotriphenylene 6aa
(27 mg, 93% yield) as a colorless solid.
9,14-Dihydro-9,14-di(2-thienyl)-9,14-epoxybenzo[b]triphenylene 5af: 1H
NMR (500 MHz, CDCl3): δ = 7.05 (dd, J = 9.0, 4.0 Hz, 2H), 7.22–7.28 (m,
2H), 7.43 (ddd, J = 10.0, 7.0, 1.0 Hz, 2H), 7.57 (ddd, J = 8.0, 7.5, 1.5 Hz,
9,14-Diphenylbenzo[b]triphenylene 6aa: 1H NMR (500 MHz, CDCl3): δ =
6.97 (ddd, J = 8.5, 7.0, 1.0 Hz, 2H), 7.33 (ddd, J = 8.5, 7.0, 1.0 Hz, 2H),
7.42–7.46 (m, 2H), 7.46–7.57 (m, 12H), 7.91–7.95 (m, 2H), 8.26 (dd, J =
8.1, 1.0 Hz, 2H); 13C NMR (126 MHz, CDCl3): δ = 123.3, 125.6, 125.8,
126.7, 126.8, 127.6, 128.9, 129.0, 130.5, 131.3, 131.7, 131.9, 132.6,
135.4, 141.7; IR (neat): ν~ = 3062, 1487, 1439, 744, 702 cm–1; HRMS
(APCI+): calcd. for C34H23 [M+H]+: 431.1800; found: 431.1789.
2H), 7.56–7.61 (m, 2H), 7.76–7.82 (m, 6H), 8.69 (d, J = 8.4 Hz, 2H); 13
C
NMR (126 MHz, CDCl3): δ = 88.8, 121.2, 123.5, 124.0, 125.7, 126.2,
126.4, 126.8, 127.3, 127.8, 129.7, 130.5, 138.0, 147.1, 150.8; IR (neat):
ν~ = 1215, 771, 744, 723, 667 cm–1; HRMS (APCI+): calcd. for C30H19OS2
[M+H]+: 459.0877; found: 459.0876.
5,16-Dihydro-5,16-diphenyl-5,16-epoxybenzo[h]pentaphene 5ba: 1H
NMR (500 MHz, CDCl3): δ = 6.95–7.01 (m, 2H), 7.36 (ddd, J = 8.5, 7.0,
1.0 Hz, 1H), 7.40 (ddd, J = 8.0, 6.5, 1.3 Hz, 1H), 7.45 (ddd, J = 8.0, 6.5,
1.4 Hz, 1H), 7.48–7.57 (m, 7H), 7.60 (dd, J = 8.3, 0.8 Hz, 1H), 7.64 (d, J
= 8.5 Hz, 1H), 7.66–7.69 (m, 1H), 7.71–7.75 (m, 1H), 8.01 (d, J = 8.0 Hz,
1H), 8.06 (s, 1H), 8.08 (d, J = 6.0 Hz, 2H), 8.11 (br s, 2H), 8.81 (d, J =
8.0 Hz, 1H), 9.14 (s, 1H); 13C NMR (126 MHz, CDCl3): δ = 93.3, 121.9,
122.0, 122.5, 123.1, 123.7, 124.7, 125.16, 125.22, 125.7, 125.9, 126.49,
126.55, 127.5, 128.1, 128.3, 128.77, 128.79, 129.1, 129.39, 129.45,
130.3 (br s), 130.9, 131.2, 131.3, 135.0, 135.1, 148.8, 148.9, 151.07,
151.15; IR (neat): ν~ = 3014, 1215, 746, 698, 667 cm–1; HRMS (APCI+):
calcd. for C38H25O [M+H]+: 497.1905; found: 497.1920.
9,14-Di(4-methoxyphenyl)benzo[b]triphenylene 6ab: 1H NMR (500 MHz,
CDCl3): δ = 3.91 (s, 6H), 7.00 (ddd, J = 8.4, 7.2, 1.2 Hz, 2H), 7.05–7.08
(m, 4H), 7.33 (ddd, J = 8.1, 7.0, 1.1 Hz, 2H), 7.42–7.47 (m, 6H), 7.54 (dd,
J = 8.5, 1.1 Hz, 2H), 7.96 (br d, J = 6.6 Hz, 2H), 8.25 (dd, J = 8.5, 1.1 Hz,
2H); 13C NMR (126 MHz, CDCl3): δ = 55.4, 123.3, 125.5, 125.8, 126.6,
126.7, 129.0, 130.3, 131.6, 131.9, 132.1, 133.7 (2C), 133.9, 134.8,
159.2; IR (neat): ν~ = 1217, 912, 771, 748, 731 cm–1; HRMS (APCI+):
calcd. for C36H27O2 [M+H]+: 491.2011; found: 491.2025.
9,14-Di(4-hexylphenyl)benzo[b]triphenylene 6ac: 1H NMR (500 MHz,
CDCl3): δ = 0.93 (t, J = 7.1 Hz, 6H), 1.32–1.46 (m, 12H), 1.73 (tt, J = 7.7,
7.6 Hz, 4H), 2.74 (t, J = 7.7 Hz, 4H), 6.95 (ddd, J = 8.4, 7.1, 1.3 Hz, 2H),
7.30–7.34 (m, 6H), 7.42–7.46 (m, 6H), 7.50 (dd, J = 8.4, 1.0 Hz, 2H),
7.96–8.00 (m, 2H), 8.25 (dd, J = 8.4, 1.2 Hz, 2H); 13C NMR (126 MHz,
CDCl3): δ = 14.1, 22.7, 28.9, 31.4, 31.8, 35.8, 123.2, 125.5, 125.6, 126.6,
126.8, 128.9, 129.0, 130.4, 131.5, 131.8, 131.9, 132.4, 135.3, 138.8,
142.3; IR (neat): ν~ = 2925, 2854, 904, 752, 727 cm–1; HRMS (APCI+):
calcd. for C46H47 [M+H]+: 599.3678; found: 599.3667.
11,16-Dihydro-11,16-diphenyl-11,16-epoxynaphtho[2,3-g]chrysene 5ca:
1H NMR (500 MHz, CDCl3, –40 °C): δ = 6.95 (dd, J = 7.7, 7.7 Hz, 1H),
7.02 (dd, J = 7.7, 7.7 Hz, 1H), 7.10 (d, J = 7.8 Hz, 1H), 7.21 (dd, J = 7.2
Hz, 1H), 7.23 (d, J = 7.2 Hz, 1H), 7.29 (dd, J = 7.4, 7.4 Hz, 1H), 7.36–
7.45 (m, 3H), 7.48–7.68 (m, 4H), 7.51 (dd, J = 7.4, 7.4 Hz, 1H), 7.56 (dd,
J = 7.7, 7.7 Hz, 1H), 7.87 (d, J = 7.9 Hz, 1H), 7.89–7.96 (m, 3H), 8.03 (d,
J = 7.1 Hz, 1H), 8.24 (d, J = 7.7 Hz, 1H), 8.36 (br s, 1H), 8.72 (d, J = 9.1
Hz, 1H), 8.76 (d, J = 8.6 Hz, 1H); 13C NMR (126 MHz, CDCl3, –40 °C): δ
= 91.9, 94.7, 121.2, 122.4, 122.8, 123.2, 123.8, 124.4, 125.2, 125.4,
125.5, 125.6, 125.9, 126.0, 126.2, 126.9, 126.97, 127.04, 127.4, 127.7,
128.0 (br), 128.56, 128.59, 128.62 (br), 128.7, 128.8 (br), 129.3, 129.5,
129.6, 129.8, 132.0, 134.0, 135.0, 147.6, 147.9, 149.8, 151.2; IR (neat):
ν~ = 3055, 1454, 1300, 906, 727, 698 cm–1; HRMS (APCI+): calcd. for
C38H25O [M+H]+: 497.1905; found: 497.1903.
9,14-Di(4-tert-butylphenyl)benzo[b]triphenylene 6ad: 1H NMR (500 MHz,
CDCl3): δ = 1.42 (s, 18H), 6.93 (dd, J = 7.7, 7.7 Hz, 2H), 7.30 (dd, J = 7.7,
7.7 Hz, 2H), 7.39–7.48 (m, 8H), 7.52 (d, J = 8.1 Hz, 4H), 7.99–8.02 (m,
2H), 8.23 (d, J = 8.0 Hz, 2H); 13C NMR (126 MHz, CDCl3): δ = 31.5, 34.7,
123.2, 125.5, 125.6, 125.8, 126.6, 126.8, 129.0, 130.4, 131.6, 131.88,
131.92, 132.2, 135.3, 138.6, 150.7; IR (neat): ν~ = 2962, 2925, 912, 748,
727 cm–1; HRMS (APCI+): calcd. for C42H39 [M+H]+: 543.3052; found:
543.3046.
Generation
and
Diels–Alder
reaction
of
arynes
(from
9,14-Di(4-fluorophenyl)benzo[b]triphenylene 6ae: 1H NMR (500 MHz,
CDCl3): δ = 7.02 (ddd, J = 8.0, 7.0, 1.0 Hz, 2H), 7.23 (dd, J = 8.4, 8.4 Hz,
4H), 7.37 (ddd, J = 8.0, 7.0, 1.0 Hz, 2H), 7.44–7.54 (m, 8H), 7.86–7.91
(m, 2H), 8.27 (dd, J = 8.4, 1.0 Hz, 2H); 13C NMR (126 MHz, CDCl3): δ =
116.1 (d, JCF = 21 Hz), 123.4, 125.9 (d, JCF = 5 Hz), 126.4, 127.0, 129.1,
130.3, 131.0, 131.8, 132.0, 134.1, 134.2, 134.3, 137.4 (d, JCF = 3 Hz),
162.5 (d, JCF = 248 Hz); 19F NMR (470 MHz, CDCl3): δ = 47.4–47.5 (m);
IR (neat): ν~ = 1506, 1223, 845, 750, 727 cm–1; HRMS (APCI+): calcd. for
C34H21F2 [M+H]+: 467.1611; found: 467.1618.
fluorohelicenes). Synthesis of adduct 5da is described as a typical
procedure. To a THF solution (2 mL) of fluorohelicene 2d (40 mg, 0.16
mmol) and isobenzofuran 4a (87 mg, 0.32 mmol) was added a THF
solution of Me2(TMP)ZnLi (0.30 mol/L, 1.2 mL, 0.35 mmol)[21] at –78 °C.
The resulting solution was heated to reflux and stirred for 6 h. Saturated.
aq. NH4Cl was added to quench the reaction and organic materials were
extracted with dichloromethane three times. The combined extracts were
washed with brine and dried over anhydrous Na2SO4. After removal of
the solvent under reduced pressure, the residue was purified by column
chromatography on silica gel (hexane/ethyl acetate 20:1) to give adduct
5da (74 mg, 93% yield) as a pale yellow solid.
9,14-Di(2-thienyl)benzo[b]triphenylene 6af: 1H NMR (500 MHz, CDCl3): δ
= 7.09 (ddd, J = 7.5, 7.0, 1.0 Hz, 2H), 7.25–7.29 (m, 2H), 7.34–7.37 (m,
2H), 7.39 (ddd, J = 8.0, 7.0, 1.0 Hz, 2H), 7.50–7.55 (m, 4H), 7.70 (dd, J =
9,14-Dihydro-9,14-diphenyl-9,14-epoxydibenzo[b,p]chrysene 5da: 1H
NMR (500 MHz, CDCl3): δ = 6.98–7.06 (m, 2H), 7.34 (dd, J = 7.4, 7.4 Hz,
1H), 7.44–7.60 (m, 12H), 7.60–7.67 (m, 2H), 7.69 (d, J = 6.7 Hz, 1H),
7.74 (d, J = 8.2 Hz, 1H), 7.89 (d, J = 7.7 Hz, 1H), 8.00–8.12 (m, 2H), 8.97
(d, J = 8.3 Hz, 1H), 9.03 (d, J = 8.5 Hz, 1H); 13C NMR (126 MHz, CDCl3):
δ = 93.28, 93.34, 122.0, 122.1, 122.5, 123.8, 125.29, 125.33, 125.5,
125.8, 125.9, 125.99, 126.04, 126.3, 127.6, 128.2, 128.3, 128.76, 128.80,
128.9, 129.1, 129.4, 129.5, 130.3, 130.4, 130.8, 132.9, 134.7, 134.9,
148.0, 149.1, 151.1, 151.2; IR (neat): ν~ = 2925, 1454, 1259, 1090, 1020,
748, 698 cm-1; HRMS (APCI+): calcd. for C38H24O [M+H]+: 497,1900;
found: 497.1904.
8.5, 1.0 Hz, 2H), 8.23–8.27 (m, 2H), 8.27 (dd, J = 8.5, 1.0 Hz, 2H); 13
C
NMR (126 MHz, CDCl3): δ = 123.4, 126.1, 126.28, 126.32, 127.2, 127.4,
127.7, 127.8, 129.0, 130.4, 130.4, 131.1, 131.8, 132.5, 142.7; IR (neat):
ν~ = 2922, 1259, 1095, 1024, 798 cm–1; HRMS (APCI+): calcd. for
C30H19S2 [M+H]+: 443.0928; found: 443.0930.
5,16-Diphenylbenzo[h]pentaphene 6ba: 1H NMR (500 MHz, CDCl3): δ =
6.98 (ddd, J = 8.5, 7.0, 1.0 Hz, 1H), 7.28 (d, J = 7.6 Hz, 1H), 7.31 (ddd, J
= 7.6, 6.5, 1.1 Hz, 1H), 7.35 (ddd, J = 7.9, 6.9, 1.2 Hz, 1H), 7.41 (ddd, J =
8.5, 6.7, 1.5 Hz, 1H), 7.44–7.60 (m, 11H), 7.62–7.66 (m, 2H), 7.90 (d, 8.2
Hz, 1H), 7.92–7.97 (m, 2H), 7.98 (s, 1H), 8.38 (dd, J = 8.1, 0.8 Hz, 1H),
8.66 (s, 1H); 13C NMR (126 MHz, CDCl3): δ = 121.5, 123.9, 125.5, 125.67,
125.70, 126.1, 126.2, 126.6, 126.8, 126.9, 127.3, 127.5, 127.6, 128.3,
128.9, 129.1, 129.2, 129.3, 129.6, 130.7, 130.7, 130.9, 131.66, 131.69,
131.8, 132.0, 132.1, 132.3, 132.5, 132.6, 135.6, 135.6, 141.5, 141.7; IR
(neat): ν~ = 3053, 1489, 906, 737, 704 cm–1; HRMS (APCI+): calcd. for
C38H25 [M+H]+: 481.1956; found: 481.1956.
Reductive aromatisation of Diels–Alder adducts. Synthesis of
benzotriphenylene 6aa is described as a typical procedure. To a THF
solution (3 mL) of Diels–Alder adduct 5aa (28 mg, 0.055 mmol) and
SnCl2 (167 mg, 0.88 mmol) was added c. HBr (0.2 mL, 1.7 mmol) at
room temperature. The resulting solution was heated to 60 °C and stirred
for 10 h. A small amount of SiO2 was added to the resulting mixture. After
7
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11,16-Diphenylnaphtho[2,3-g]chrysene 6ca: 1H NMR (500 MHz, CDCl3,
–
750 cm–1; HRMS (APCI+): calcd. for C46H43 [M+H]+: 595.3365; found:
595.3353.
40 °C): δ = 6.49 (d, J = 7.7 Hz, 1H), 6.79 (dd, J = 7.5, 7.5 Hz, 1H), 7.01
(dd, J = 7.5, 7.5 Hz, 1H), 7.08 (dd, J = 7.7, 7.7 Hz, 1H), 7.10 (dd, J = 7.7,
7.7 Hz, 1H), 7.21 (dd, J = 7.7, 7.7 Hz, 1H), 7.34 (dd, J = 7.7, 7.7 Hz, 1H),
7.41–7.65 (m, 8H), 7.75 (dd, J = 7.5, 7.5 Hz, 1H), 7.83 (d, J = 7.5 Hz, 1H),
7.86 (d, J = 8.8 Hz, 1H), 7.95 (d, J = 8.3 Hz, 1H), 7.99 (dd, J = 6.5, 2.7
Hz, 1H), 8.19 (d, J = 7.7 Hz, 1H), 8.27 (d, J = 7.9 Hz, 1H), 8.38 (d, J = 8.8
Hz, 1H), 8.48 (d, J = 8.3 Hz, 1H); 13C NMR (126 MHz, CDCl3, –40 °C): δ =
120.1, 123.3, 124.9, 125.0, 125.4, 125.5, 125.9, 126.47, 126.55, 126.63,
126.7, 126.80, 126.82, 127.1, 127.56, 127.64, 127.9, 127.9, 128.3, 128.6,
128.7, 129.0, 129.2, 129.5, 129.5, 130.0, 131.1, 131.3, 131.4, 131.81,
7,16-Di-tert-butyldibenzo[fg,ij]naphtho[1,2,3,4-rst]pentaphene 10ad: 1H
NMR (500 MHz, CDCl3): δ = 1.51 (s, 18H), 7.62 (dd, J = 6.5, 3.3 Hz, 2H),
7.73 (dd, J = 8.6, 1.9 Hz, 2H), 7.89 (dd, J = 7.9, 7.9 Hz, 2H), 8.75 (d, J =
2.0 Hz, 2H), 8.76 (d, J = 7.9 Hz, 2H), 8.81 (d, J = 8.0 Hz, 2H), 8.86 (d, J =
8.6 Hz, 2H), 9.09 (dd, J = 6.4, 3.4 Hz, 2H); 13C NMR (126 MHz, CDCl3): δ
= 31.6, 35.2, 119.7, 121.5, 121.6, 121.9, 124.6, 124.7, 125.0, 125.6,
126.7, 127.4, 128.5, 128.9, 129.6, 130.0, 130.4, 130.8, 149.6; IR (neat):
ν
~ = 2956, 2922, 1259, 1018, 796 cm–1; HRMS (APCI+): calcd. for C42H35
[M+H]+: 539.2739; found: 539.2745.
131.84, 132.3, 133.0, 133.6, 134.4, 137.3, 139.8, 141.2; IR (neat): ν~
3053, 2924, 1489, 906, 729, 702 cm–1; HRMS (APCI+): calcd. for C38H25
[M+H]+: 481.1956; found: 481.1954.
=
Acknowledgements
9,14-Diphenyldibenzo[b,p]chrysene 6da: 1H NMR (500 MHz, CDCl3): δ =
7.03 (ddd, J = 7.7, 7.7, 1,3 Hz, 1H), 7.33 (ddd, J = 7.6, 7.6, 1.1 Hz, 1H),
7.40 (d, J = 9.1 Hz, 1H), 7.44–7.64 (m, 16H), 7.76 (dd, J = 8.0, 1.2 Hz,
1H), 7.96–8.02 (m, 2H), 8.39 (dd, J = 8.1, 1.1 Hz, 1H), 8.83 (d, J = 8.5 Hz,
1H); 13C NMR (126 MHz, CDCl3): δ = 125.51, 125.54, 125.6, 125.7, 125.8,
125.9, 126.3, 126.7, 126.8, 127.6, 127.8, 129.5, 129.6, 129.9, 130.0,
130.7, 131.8, 132.0, 132.7, 132.8, 132.9, 133.0, 134.6, 134.8, 141.2,
141.6; IR (neat): ν~ = 3060, 3022, 1493, 752, 704 cm–1; HRMS (APCI+):
calcd. for C38H24 [M+H]+: 481.1951; found: 481.1965.
This research is supported by JSPS KAKENHI Grant Numbers
JP18H04234 and JP19H02707. TOSOH FINECHEM COOPERATION is
acknowledged for the generous gift of CF3CH2I.
Keywords: aryne • fluorine • PAH • domino reactions • triphenylene
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9,9-Di(4-methoxyphenyl)benzo[b]triphenylen-14(9H)-one 7ab: 1H NMR
(500 MHz, CDCl3): δ = 3.60 (s, 3H), 3.81 (s, 3H), 6.55 (d, J = 8.9 Hz, 2H),
6.62 (d, J = 7.4 Hz, 1H), 6.64 (dd, J = 8.5, 2.0 Hz, 1H), 6.69 (dd, J = 8.5,
2.6 Hz, 1H), 6.75 (ddd, J = 8.0, 8.0, 0.9 Hz, 1H), 6.84–6.88 (m, 2H), 6.99
(ddd, J = 8.5, 7.7, 1.1 Hz, 1H), 7.07 (dd, J = 8.5, 2.6 Hz, 1H), 7.10 (d, J =
8.0 Hz, 1H), 7.34 (ddd, J = 8.8, 7.5, 1.3 Hz, 1H), 7.38 (ddd, J = 8.5, 6.6,
0.9 Hz, 1H), 7.43 (ddd, J = 8.5, 7.5, 1.0 Hz, 1H), 7.47 (ddd, J = 9.0, 7.7,
1.4 Hz, 1H), 7.49 (d, J = 8.0 Hz, 1H), 7.53 (dd, J = 8.4, 2.1 Hz, 1H), 7.61
(dd, J = 7.8, 1.1 Hz, 1H), 7.80 (dd, J = 7.8, 1.0 Hz, 1H), 8.26 (dd, J = 7.8,
1.5 Hz, 1H); 13C NMR (126 MHz, CDCl3): δ = 54.9, 55.2, 60.4, 113.3,
113.3, 113.7, 114.1, 123.2, 125.6, 126.8, 127.28, 127.28, 127.31, 127.4,
128.0, 128.06, 128.09, 128.12, 129.0, 129.0, 129.4, 130.0, 132.2, 132.4,
132.5, 134.1, 134.4, 134.5, 134.9, 135.3, 135.5, 139.9, 141.8, 158.1,
158.9, 197.6; IR (neat): ν~ = 2925, 1670, 1506, 1244, 748 cm–1; HRMS
(APCI+): calcd. for C36H27O3 [M+H]+: 507.1960; found: 507.1960.
Oxidative aryl–aryl coupling leading to half HBC. Synthesis of half
HBC 10aa is described as
a typical procedure. To a mixed 1,2-
dichloroethane–MeNO2 solution (10:1, 11 mL) of FeCl3 (523 mg, 3.22
mmol) was added benzotriphenylene 6aa (46 mg, 0.11 mmol) at 0 °C.
The resulting solution was stirred for 1 h. MeOH was added to quench
the reaction and organic materials were extracted with dichloromethane
three times. The combined extracts were washed with brine and dried
over anhydrous Na2SO4. After removal of the solvent under reduced
pressure, the residue was purified by column chromatography on silica
gel (dichloromethane) to give half HBC 10aa (38 mg, 84% yield) as a
yellow solid.
[4]
Dibenzo[fg,ij]naphtho[1,2,3,4-rst]pentaphene 10aa: 1H NMR (500 MHz,
CDCl3): δ = 7.70 (dd, J = 6.4, 3.4 Hz, 2H), 7.71–7.77 (m, 4H), 7.96 (dd, J
= 7.9, 7.9 Hz, 2H), 8.80 (d, J = 7.5 Hz, 2H), 8.82 (d, J = 7.9 Hz, 4H),
8.94–9.00 (m, 2H), 9.11 (dd, J = 6.4, 3.4 Hz, 2H); 13C NMR (126 MHz,
CDCl3): δ = 121.7, 121.8, 122.1, 123.8, 124.5, 125.2, 125.7, 126.4, 126.8,
[5]
[6]
[7]
126.9, 128.4, 128.9, 129.5, 129.8, 129.9, 130.1, 131.2; IR (neat): ν~
=
1261, 1092, 1018, 796, 741 cm–1; HRMS (APCI+): calcd. for C34H19
[M+H]+: 427.1487; found: 427.1477.
7,16-Dihexyldibenzo[fg,ij]naphtho[1,2,3,4-rst]pentaphene 10ac: 1H NMR
(500 MHz, CDCl3): δ = 0.93 (t, J = 6.8 Hz, 6H), 1.32–1.42 (m, 8H), 1.47
(tt, J = 7.6, 7.2 Hz, 4H), 1.80 (tt, J = 7.8, 7.6 Hz, 4H), 2.85 (t, J = 7.8 Hz,
4H), 7.44 (d, J = 8.4 Hz, 2H), 7.60 (dd, J = 6.5, 3.1 Hz, 2H), 7.72 (dd, J =
7.8, 7.8 Hz, 2H), 8.41 (s, 2H), 8.53 (d, J = 8.0 Hz, 2H), 8.61 (d, J = 8.1 Hz,
2H), 8.74 (d, J = 8.3 Hz, 2H), 9.00 (dd, J = 6.4, 3.4 Hz, 2H); 13C NMR
(126 MHz, CDCl3): δ = 14.2, 22.7, 29.2, 31.6, 31.8, 36.4, 121.2, 121.4,
121.6, 122.9, 124.4, 124.8, 125.4, 126.3, 127.1, 127.4, 128.4, 128.8,
129.6, 129.7, 129.8, 131.0, 141.3; IR (neat): ν~ = 2924, 1466, 1441, 806,
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9
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FULL PAPER
Entry for the Table of Contents
In(III)-Catalyzed
Oxidative
Aryl–Aryl Coupling
Diels–Alder Rxn /
Reduction
Domino Ring Assembly
X
F
CF2
π-Extended
Arynes
CN
Aryne Precursors
(X = Br, I and H)
Benzotriphenylenes
Half Hexabenzocoronenes
1,1-Difluoroallenes bearing a cyclopentene moiety and an aryl group underwent In-catalyzed domino ring assembly to afford aryne
precursors such as ortho-fluoro(halo)phenanthrenes and fluoro[4]helicenes. Their elimination of XF generated π-extended arynes,
whose Diels–Alder reactions with isobenzofurans followed by aromatisation furnished benzotriphenylenes. Their aryl–aryl coupling
facilitated “half HBC” synthesis.
10
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