A short-step synthesis of 1,6-methano[10]annulene-3,4-dicarboximides and their benzene-, naphthalene-, and thiophene-annulated compounds

Article abstract of DOI:10.1002/ejoc.201402776

Triphenylphosphorane reagents 8 react with 1,3,5-cycloheptatriene-1,6-dicarbaldehyde (2) under acidic as well as basic conditions to produce 1,6-methano[10]annulene-3,4-dicarboximides 1 in moderate -to- good yields. The reagents 8 react with 3,4-arene-annulated 1,3,5-cycloheptatriene-1,6-dicarbaldehydes 9, 10, and 11 to afford only the Wittig condensation products under acidic conditions but produce the arene-annulated annulenedicarboximides under basic conditions. The structures of some of the dicarboximides and the intermediate Wittig condensation products were determined by X-ray structural analysis. The emission properties of the dicarboximides were also studied.

Full text of DOI:10.1002/ejoc.201402776

FULL PAPER
DOI: 10.1002/ejoc.201402776
A Short-Step Synthesis of 1,6-Methano[10]annulene-3,4-dicarboximides and
Their Benzene-, Naphthalene-, and Thiophene-Annulated Compounds
Mitsunori Oda,*[a] Tomomi Nakamura,[a] Miyako Neha,[a] Daisuke Miyawaki,[a]
Akira Ohta,[a] Shigeyasu Kuroda,[b] and Ryuta Miyatake[c]
Keywords: Annulenes / Annulation / Wittig reactions / Imides
Triphenylphosphorane reagents 8 react with 1,3,5-cyclohep-
tatriene-1,6-dicarbaldehyde (2) under acidic as well as basic
conditions to produce 1,6-methano[10]annulene-3,4-dicarb-
oximides 1 in moderate -to- good yields. The reagents 8 react
with 3,4-arene-annulated 1,3,5-cycloheptatriene-1,6-dicarb-
tion products under acidic conditions but produce the arene-
annulated annulenedicarboximides under basic conditions.
The structures of some of the dicarboximides and the inter-
mediate Wittig condensation products were determined by
X-ray structural analysis. The emission properties of the di-
aldehydes 9, 10, and 11 to afford only the Wittig condensa- carboximides were also studied.
Introduction
Recently, we reported the synthesis and emission behav-
ior of various N-substituted 1,6-methano[10]annulene-3,4-
dicarboximides 1,[1] and Zuo et al. independently reported
their synthesis by a slightly different route.[2] The starting
point for both syntheses is 1,3,5-cycloheptatriene-1,6-di-
carbaldehyde (2)[3] as shown in Schemes 1 and 2. The annu-
lene derivative 3 can be obtained from 2 in three steps by
the method reported by Neidlein,[4,5] and the subsequent
cyanation and hydrolysis produce a mixture of dicarboxylic
anhydride 5 and dicarboximide 6. We synthesized various
N-substituted dicarboximides 1 by either the condensation
of 5 with an amine or the nucleophilic displacement of 6
with alkyl and aryl halides. In contrast, Zuo et al. obtained
5 from diester 2[3c,6,7] and transformed 5 into 1.
Both methods require five or six steps from 2 to 1. In
respect of the interesting emission behavior of 1,[1] we envi-
sioned a more efficient synthetic conversion from 2 to 1. In
this paper, we describe a short-step synthesis of 1 from 2
with the phosphorane reagents 8 that consists of a Wittig
Scheme 1. Outline of the previously reported synthetic method of
1 from 2.
condensation and subsequent cyclization and also its appli-
cation to the synthesis of benzene-, naphthalene-, and thio-
[a] Department of Chemistry, Faculty of Science, Shinshu
University,
Asahi 3-1-1, Matsumoto, Nagano 390-8621, Japan
E-mail: mituoda@shinshu-u.ac.jp
http://www.shinshu-u.ac.jp/
[b] Department of Applied Chemistry, Graduate School of Science
and Technology, University of Toyama,
Gofuku 3190, Toyama 930-8555, Japan
[c] Centre for Environmental Conservation and Research Safety,
University of Toyama,
Gofuku 3190, Toyama 930-8555, Japan
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejoc.201402776.
Scheme 2. A synthetic method of 1 reported by Zuo et al.
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Synthesis of 1,6-Methano[10]annulene-3,4-dicarboximides
phene-annulated 1,6-methano[10]annulenedicarboximides.
We also report the X-ray crystallographic analysis of some
of the imides and intermediate Wittig condensation prod-
ucts as well as their emission properties.
Results and Discussion
First, the reaction of 2 with the triphenylphosphorane
reagent 8a,[8] obtained from triphenylphosphine and N-
phenylmaleimide, was examined. The results under various
conditions are presented in Table 1. Compound 1a[1,2] was
obtained under both acidic and basic conditions. In AcOH
with a slight excess of 8a, 1a was obtained in a satisfactory
yield (70%, Table 1, Entry 2). Under basic conditions, 1a
was obtained in moderate yields (Table 1, Entries 3–4).
However, a larger amount of strong base tends to result in
lower yields of the product (Table 1, Entries 5–6). The weak
base pyridine was used as the solvent, but the yield was low
(Table 1, Entry 7). As 8a can be prepared in AcOH at re-
flux, 8a prepared in situ was treated with 2 to provide 1a;
however, the yield was lower (48% yield) than that with
preformed 8a (Table 1, Entry 2). Under conditions similar
to those of Table 1, Entry 2, phosphoranes 8b–8i reacted
with 2 to produce 1b–1h[1] and 6 in fair-to-good yields (Fig-
ure 1). The reactivity of phosphoranes 8 with 2 is different
depending on the substituent at the nitrogen atom; there-
fore, the reaction times also differ. Although some of the
reactions produced moderate yields, we could successfully
improve the synthesis of 1 from 2 by a one-step method
with the phosphorane reagents 8.
Figure 1. 1,6-Methano[10]annulene-3,4-dicarboximides 1b–1h and
6 obtained by the reaction of 2 with the corresponding phos-
phoranes 8b–8i (1.5 equiv.) in AcOH at reflux; the reaction times
and yields are in parentheses.
Table 1. Results of the reaction of 2 and 8a under various condi-
tions.
The reactions of 9 with an equivalent amount of 8a and 8e
in AcOH at reflux presented the monocondensation prod-
ucts, 12a and 12e, as the sole products in 23 and 20% yield,
respectively; the reactions of 9 with 8b and 8c produced a
mixture of the monocondensation products, 12b (53%
yield) and 12c (48% yield), accompanied by the double-
condensation products, 13b (27% yield) and 13c (11%
yield), respectively (Scheme 3). On the other hand, the reac-
tion of 10 with 8b in AcOH produced 14 in 46% yield
(Scheme 4), and a mixture of the inseparable regioisomers
15 and 16 was obtained in 66% yield from the reaction of
11 with 8b (Scheme 5). Thus, the reactions of these arene-
annulated dicarbaldehydes 9, 10, and 11 with phosphoranes
Entry Reaction conditions
Yield[a] of 1a [%]
1
2
3
4
5
6
7
2/8a = 1.0:1.0, AcOH, reflux, 12 h
2/8a = 1.0:1.5, AcOH, reflux, 16 h
52 (33)[b]
70
2/8a/MeONa = 1.0:1.0:0.1, MeOH, reflux, 14 h 52 (22)[b]
2/8a/MeONa = 1.0:1.3:0.1, MeOH, reflux, 20 h 62
2/8a/MeONa = 1.0:1.3:0.5, MeOH, reflux, 10 h 26
2/8a/EtONa = 1.0:1.0:0.5, EtOH, reflux, 4 h
2/8a = 1.0:1.0, pyridine, reflux, 5 h
15
37
[a] Isolated yield after chromatographic purification. [b] The reco-
vered yield of 1a is in parentheses.
Secondly, we examined the reactions of the 3,4-arene-an-
nulated 1,3,5-cycloheptatriene-1,6-dicarbaldehydes 9,[9]
10,[10] and 11,[11] (Figure 2) with phosphoranes 8. These di-
carbaldehydes demonstrate different reactivity from that of
2, that is, the reactions of these dicarbaldehydes under
acidic conditions provided only the Wittig condensation
Figure 2. Structures of the 3,4-arene-annulated 1,3,5-cycloheptatri-
products unaccompanied by the desired dicarboximides. ene-1,6-dicarbaldehydes 9, 10, and 11.
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Scheme 3. Reaction of 9 with 8a, 8b, 8c, and 8e.
ensation products were successfully converted to the desired
annulenedicarboximides 17, 18, and 19, respectively, by
treatment with sodium alkoxide in an alcohol at reflux.
Their yields are shown in Table 2 (Entries 1–6). In addition
to the above results, it was found that these annulenedi-
carboximides could be synthesized directly by the reaction
of the dicarbaldehydes with 8 under basic conditions with
alkoxide. These results are also summarized in Table 2
(Entries 7–14). Although some yields of the annulenedi-
carboximides are still low and some reactions require rela-
tively long reaction times, the results demonstrate that ar-
ene-annulated annulenedicarboximides can be synthesized
in one step from suitable 1,2-dicarbaldehydes.
Scheme 4. Reaction of 10 with 8b.
In the intermediate products 12 and 14 as well as in the
mixture of 15 and 16, the conjugated carbonyl group of the
8 under acidic conditions do not produce the expected an- succinimide moiety is in a syn arrangement with the vinyl
nulenedicarboximides but instead the condensation prod- hydrogen atom Ha (Figure 3).[11] This was deduced from
ucts 12 and 14, in addition to a mixture of 15 and 16, in the somewhat low-field chemical shifts of the Ha protons
contrast with the results for 2. However, these monocond- in the NMR spectra[12] and was also confirmed by X-ray
Scheme 5. Reaction of 11 with 8a and 8b.
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Synthesis of 1,6-Methano[10]annulene-3,4-dicarboximides
Figure 3. Structures of the (E) and (Z) stereoisomers of the intermediate products and their rotational isomers.
Table 2. Synthesis of 17, 18, and 19 from dicarbaldehydes 9, 10, bond alternation between single and double C–C bonds is
and 11 with phosphoranes 8 and from the intermediates 12, 14,
observed. The deviation of the C–C bond lengths of the
and 15/16 under basic conditions.
parent 1,6-methano[10]annulene[14] from the average length
(1.396 Å) is Ϯ0.024 Å[15] and that for the annulene part in
1a from the average length (1.395 Å) is Ϯ0.023 Å; therefore,
Entry Substrate/reaction conditions
Product/
yield[a]
1
2
3
4
12a/MeONa (1.0 equiv.), MeOH, reflux, 24 h
12b/MeONa (1.0 equiv.), MeOH, reflux, 24 h
12c/MeONa (1.0 equiv.), MeOH, reflux, 24 h
12e/EtONa (1.0 equiv.), EtOH, reflux, 48 h
17a/85% the annulation of the five-membered imide ring does not
17b/70%
have any effect on the 1,6-methano[10]annulene skeleton.
On the other hand, the deviation from the average length
in 17b (1.402 Å) is Ϯ0.053 Å, and that from the average
17c/85%
17e/33%
5
14/EtONa (1.0 equiv.), EtOH, reflux, 48 h
18/32%
length in 18 (1.404 Å) is Ϯ0.080 Å, which clearly demon-
strates that the bond alternation of the annulene ring is at-
tributable to the benzene and naphthalene annulations.
6
7
8
9
10
11
12
13
14
15 + 16/MeONa (1.0 equiv.), Me, reflux, 3 h
9 + 8a[b]/MeONa (2.0 equiv.), MeOH, reflux, 70 h
9 + 8b[b]/MeONa (2.0 equiv.), MeOH, reflux, 70 h
9 + 8c[b]/MeONa (2.0 equiv.), MeOH, reflux, 70 h
10 + 8b[c]/MeONa (2.0 equiv.), MeOH, reflux, 70 h
10 + 8b[b]/EtONa (2.0 equiv.), EtOH, reflux, 50 h
11 + 8a[b]/MeONa (2.0 equiv.), MeOH, reflux, 55 h
11 + 8b[d]/MeONa (2.0 equiv.), MeOH, reflux, 40 h
11 + 8b[b]/EtONa (2.0 equiv.), EtOH, reflux, 40 h
19b/83%
17a/43%
17b/70%
17c/53%
18/33%
18/52%
19a/86%
19b/74%
19b/81%
[a] Isolated yield after chromatographic purification. [b] 1.5 equiv.
of 8 relative to the dicarbaldehyde was used. [c] 1.0 equiv. of 8 rela-
tive to the dicarbaldehyde was used. [d] 1.2 equiv. of 8 relative to
the dicarbaldehyde was used.
Figure 4. An ORTEP drawing of 12e showing our numbering sys-
crystallographic analysis of 12e and 14. ORTEP drawings tem.
of 12e and 14 are presented in Figures 4 and 5. The cyclo-
heptatriene part in 14 has an unusual almost-planar struc-
ture.[13] This stereochemical relationship of the vinylidene
succinimide opportunely demonstrates the advantage of ac-
cess to reaction sites for the subsequent intramolecular
1
aldol condensation. On the basis of the numbers of H and
13C NMR signals, the double-condensation products 13b
and 13c are found to possess a symmetrical structure
around the long molecular axis. From this fact and the
chemical shifts of the vinyl hydrogen atom Ha, it is clear
that they also possess the same stereochemical relationship
with respect to the vinyl group. The structures of the new
annulenedicarboximides were confirmed by spectroscopic
and/or combustion analyses. The crystal structures of 1a,
17b, and 18 were determined by X-ray crystallographic
analysis. Their ORTEP drawings are shown in Figures 6–8
Figure 5. An ORTEP drawing of 14 showing our numbering sys-
tem. One of two independent structures is shown.
As described above, we accomplished a short-step syn-
and reveal that their 1,6-methano[10]annulene skeletons do thesis of various N-substituted 1,6-methano[10]annulene-
not exhibit significant structural deformation, but slight 3,4-dicarboximides 1 and their arene-annulated analogs
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M. Oda et al.
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Figure 6. An ORTEP drawing of 1a showing our numbering sys-
tem.
Figure 8. An ORTEP drawing of 18 showing our numbering sys-
tem.
The different results depending on the dicarbaldehyde used
can be rationalized by the following mechanistic specu-
lation. As many 10π-electrocyclizations to form the carbon
framework of 1,6-methano[10]annulene have been report-
ed,[3c,16,17] a route from the condensation product 20 to 1
via 21 and 22 is very plausible (Scheme 6). That is, the enol-
ization of 20, the subsequent 10π-electrocyclization to gen-
erate the skeleton of 1,6-methano[10]annulene, and the final
dehydration of 22 results in the formation of the aromatic
ring to produce 1. The use of acetic acid as the solvent can
assist the enolization and also the dehydration. On the
other hand, similar enol intermediates derived from 9–11,
such as 23 in Scheme 6, should be hard to form because of
the disruption of aromaticity by the formation of a partial
quinodimethane structure.
Figure 7. An ORTEP drawing of 17b showing our numbering sys-
tem.
The photophysical data of the N-methyldicarboximides
1b, 17b, 18, and 19b are listed in Table 3. The UV/Vis ab-
from dicarbaldehydes 2 and 9–11. Although 2 reacts with sorption spectra show four main absorption bands above
phosphorane reagents 8 under acidic conditions directly to 240 nm, except for that of 18, which has three main
produce 1, 9–11 react with 8 under the same acidic condi- bands.[18] From their wavelengths and relatively small molar
tions to produce only the Wittig condensation products. coefficients, the longest-wavelength bands in the absorption
Scheme 6. A possible reaction mechanism from 2 to 1 under acidic conditions and the corresponding intermediate 23 to 21 starting from
9.
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Synthesis of 1,6-Methano[10]annulene-3,4-dicarboximides
Mass spectra were recorded with a JMS-700 mass spectrometer.
Column chromatography was performed with Silica gel 60N from
Kanto Chem. Phthalaldehyde, thiophene-2,3-dicarbaldehyde, tri-
phenylphosphine, N-phenylmaleimide, N-methylmaleimide, and N-
ethylmaleimide were purchased from Tokyo Chemical Industry,
Inc. A pentanedial aqueous solution was purchased from Aldrich
Chem. Co. 2,3-Naphthaldehyde was prepared from phthalaldehyde
and 2,5-dimethoxytetrahydrofuran by the method of Lepage et
al.[19] The dicarbaldehyde 2 was prepared in five steps from 1,3,5-
cycloheptatriene according to the method of Vogel et al.[20] The
spectra (except for that of 18) can be assigned to the n–π*
transition of the imide carbonyl groups. The other absorp-
tion bands can be assigned to π–π* transitions, which exhi-
bit relatively high molar coefficients and clear redshifts
along with a degree of π-conjugation. In particular, the
third-lowest energy bands in the spectra show an obvious
redshift of 40–60 nm as a result of arene annulation. As the
longest-wavelength absorption for 18 at 422 nm exhibits a
greater molar coefficient than those of the n–π* transition
bands of the other compounds, it can be assigned to a dicarbaldehydes 9 and 10 were prepared from phthalaldehyde and
2,3-naphthaldehyde with pentanedial by the method of Lepage et
al.[9] The phosphorane reagents 8a and 8i was prepared from the
corresponding maleimides with triphenylphosphine by the method
of Hedaya et al.[8a]
π–π* transition. The n–π* transition absorption band of 18
is probably concealed by the longest-wavelength band. All
of the dicarboximides show emission upon excitation of the
long-wavelength bands. The benzene-annulated compound
17b displays a comparable emission quantum yield (10%)
to that of 1b. However, the quantum yields of 18 and 19b
were found to be less than 1%.
Preparation of Phosphorane Reagents 8: A mixture of N-substituted
maleimide (10.0 mmol) and triphenylphosphine (10.5 mmol) in
AcOH (20 mL) under a nitrogen atmosphere was heated to reflux
with an oil bath for 3 h, and then the solvent was removed under
vacuum. The slightly brown residual oil was crystallized by the ad-
dition of diethyl ether or diethyl ether/acetone. The crystalline
product was collected by suction filtration and washed well with
dry diethyl ether.
Table 3. Photophysical data of the N-methyldicarboximides 1b, 17b,
18, and 19b.
UV/Vis absorption λmax [nm] (logε)
λem [nm] (Φ)[a]
1b
246 (4.39), 286 (4.69), 325 (3.81), 420 (3.11)
470 (0.097)[b]
N-Phenyltriphenylphosphoranylidenesuccinimide (8a): Colorless so-
lid (90% yield), m.p. 165–167 °C (ref.[8a] 176.5–178.5 °C). 1H NMR
(500 MHz, CDCl3): δ = 7.65 (m, 9 H), 7.53 (m, 6 H), 7.46 (m, 2
H), 7.39 (m, 2 H), 7.23 (tt, J = 7.4, 1.4 Hz, 1 H), 3.16 (d, J =
1.5 Hz, 2 H) ppm. 13C NMR (125 MHz, CDCl3): δ = 176.0 (d,
17b 276 sh (4.39), 305 (4.65), 367 (3.72), 436 sh (3.21) 527 (0.10)
18
278 (4.48), 318 (4.75), 422 (3.81)
568 (0.0058)
19b 285 (4.37), 315 (4.75), 359 (3.89), 437 (3.21)
532 (0.0028)
[a] Photoexcitation at the longest-wavelength absorption maxi-
mum. [b] Taken from ref.[1]
2
2
3JC,P = 16.7 Hz), 169.9 (d, JC,P = 15.5 Hz), 134.1, 133.4 (d, JC,P
4
3
= 10.7 Hz), 132.7 (d, JC,P = 2.4 Hz), 129.2 (d, JC,P = 11.9 Hz),
128.5, 126.7, 126.7, 125.5 (d, JC,P = 91.8 Hz), 37.0 (d, JC,P
9.5 Hz), 36.0 (d, JC,P = 137.1 Hz) ppm.
1
2
=
1
Conclusions
N-Methyltriphenylphosphoranylidenesuccinimide (8b): Colorless so-
We have demonstrated a short-step synthesis of the an-
nulenedicarboximides 1, 17, 18, and 19 by the reactions of
1,3,5-cycloheptatriene-1,6-dicarbaldehyde (2) and its arene-
annulated dicarbaldehydes 9, 10, and 11 with phosphorane
8. Although 1 can be obtained in one step under either
acidic or basic conditions, 17, 18, and 19 were obtained in
one step only under basic conditions. The synthesis of 1 by
our method presents a clear improvement compared with
previously reported procedures. The dicarbaldehydes 9, 10,
1
lid (78% yield), m.p. 158–160 °C. H NMR (500 MHz, CDCl3): δ
= 7.61 (m, 9 H), 7.52 (m, 6 H), 3.01 (s, 3 H), 2.99 (d, J = 1.5 Hz,
3
2 H) ppm. 13C NMR (125 MHz, CDCl3): δ = 177.3 (d, JC,P
=
2
2
16.4 Hz), 171.2 (d, JC,P = 15.2 Hz), 133.3 (d, JC,P = 10.7 Hz),
132.6 (d, 4JC,P = 2.4 Hz), 129.1 (d, 3JC,P = 12.2 Hz), 125.6 (d, 1JC,P
2
1
= 93.2 Hz), 36.9 (d, JC,P = 10.4 Hz), 35.3 (d, JC,P = 139.9 Hz),
24.3 ppm. MS (FAB): m/z (%) = 374 (100) [M + H]+, 279 (18), 262
(10), 183 (11). HRMS: calcd. for C23H21NO2P [M + H]+ 374.1304;
found 374.1313.
and 11 react with phosphorane 8 to produce mono- and N-Ethyltriphenylphosphoranylidenesuccinimide (8c): Colorless solid
(85% yield), m.p. 171–173 °C. 1H NMR (500 MHz, CDCl3): δ =
double-condensation products, the former of which can be
transformed to the annulenedicarboximides 17, 18, and 19.
The crystal structures of some annulenedicarboximides and
the intermediate condensation products were determined by
X-ray analysis. The structures of the latter can conveniently
rationalize the basic intramolecular cyclization.
7.60 (m, 9 H), 7.52 (m, 6 H), 3.58 (q, J = 7.0 Hz, 2 H), 2.98 (d, J
= 1.4 Hz, 2 H) 1.20 (t, J = 7.0 Hz, 3 H) ppm. 13C NMR (125 MHz,
3
2
CDCl3): δ = 177.0 (d, JC,P = 16.1 Hz), 170.9 (d, JC,P = 15.5 Hz),
133.3 (d, 2JC,P = 10.4 Hz), 132.6 (d, 4JC,P = 2.5 Hz), 129.1 (d, 3JC,P
1
2
= 12.0 Hz), 125.7 (d, JC,P = 92.0 Hz), 36.6 (d, JC,P = 10.5 Hz),
1
35.1 (d, JC,P = 137.9 Hz), 32.8, 13.8 ppm. MS (FAB): m/z (%) =
388 (100) [M + H]+, 280 (12), 279 (59), 262 (10), 137 (21), 107 (10),
89 (11), 77 (12). HRMS: calcd. for C24H23NO2P [M + H]+
388.1461; found 388.1469.
Experimental Section
General Remarks: Melting points were measured with a Yanaco
MP-3 instrument. IR spectra were recorded with JEOL Diamond-
20 and JASCO FT/IR-4100 spectrometers. UV/Vis spectra were re-
corded with a Shimadzu UV-2550 spectrometer. Emission spectra
N-(4-Methoxyphenyl)triphenylphosphoranylidenesuccinimide (8d):[8b,21]
Colorless solid (82% yield), m.p. 171–172 °C. 1H NMR (500 MHz,
CDCl3): δ = 7.64 (m, 9 H), 7.53 (m, 6 H), 7.36 (dt, J = 9.0, 2.7 Hz,
2 H), 6.93 (dt, J = 9.0, 2.7 Hz, 2 H), 3.78 (s, 3 H), 3.14 (d, J =
1.2 Hz, 2 H) ppm. 13C NMR (125 MHz, CDCl3): δ = 176.2 (d,
1
were recorded with a Shimadzu RT-5300PC spectrometer. H and
13C NMR spectra were recorded with JEOL lambda 400 and
ECA500 spectrometers. Tetramethylsilane (δ = 0 ppm) was used as
the internal standard for 1H NMR spectra, and CDCl3 (δ =
77.0 ppm) was used as the internal standard for 13C NMR spectra.
3JC,P = 15.8 Hz), 170.1 (d, JC,P = 15.6 Hz), 158.2, 133.4 (d, JC,P
2
2
4
3
= 10.8 Hz), 132.7 (d, JC,P = 2.6 Hz), 129.2 (d, JC,P = 12.2 Hz),
1
2
127.9, 127.0, 125.5 (d, JC,P = 93.2 Hz), 114.0, 55.5, 37.0 (d, JC,P
1
= 10.1 Hz), 35.9 (d, JC,P = 137.1 Hz) ppm. MS (FAB): m/z (%) =
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466 (100) [M + H]+, 279 (39), 262 (13), 183 (11), 155 (11), 138 (13),
137 (29), 107 (14), 91 (10), 90 (10), 89 (14), 77 (15). HRMS: calcd.
for C29H25NO3P [M + H]+ 466.1567; found 466.1568.
0.300 mmol) in AcOH (2 mL) under a nitrogen atmosphere was
heated to reflux with an oil bath for 16 h, and then the solvent was
removed under vacuum. The residue was carefully poured into a
cold NaHCO3 aqueous solution and extracted with CHCl3
(10 mLϫ3). The combined organic layers were washed with brine
and dried with Mg2SO4. The solvent was evaporated, and the
brown residue was purified by silica gel chromatography (hexane/
EtOAc 85:15) to give 1a (40.2 mg, 70%) as yellow prisms, m.p. 159–
160 °C (ref.[2] 170–171 °C; ref.[1a] 158–159 °C). 1H NMR (400 MHz,
CDCl3): δ = 8.37 (s, 2 H), 7.64 (m, 2 H), 7.49 (m, 4 H), 7.40 (m, 1
H), 7.36 (m, 2 H), 0.21 (dt, J = 9.9, 1.2 Hz, 1 H), –0.14 (dt, J =
9.9, 1.1 Hz, 1 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 169.1,
132.1, 130.9, 130.1, 129.2, 129.0, 128.1, 128.0, 126.5, 119.6,
35.5 ppm.
N-(4-Bromophenyl)triphenylphosphoranylidenesuccinimide (8e): Col-
orless solid (83% yield), m.p. 163–165 °C. 1H NMR (500 MHz,
CDCl3): δ = 7.64 (m, 9 H), 7.54 (m, 6 H), 7.55 (dt, J = 8.9, 2.4 Hz,
2 H), 7.44 (dt, J = 8.9, 2.4 Hz, 2 H), 3.14 (d, J = 1.5 Hz, 2 H) ppm.
13C NMR (125 MHz, CDCl3): δ = 175.7 (d, 3JC,P = 16.4 Hz), 169.3
2
2
(d, JC,P = 16.4 Hz), 133.3 (d, JC,P = 10.2 Hz), 133.2, 132.8 (d,
4JC,P = 3.2 Hz), 131.5, 129.2 (d, JC,P = 12.9 Hz), 128.0, 125.2 (d,
3
1JC,P = 92.0 Hz), 120.0, 36.9 (d, JC,P = 10.4 Hz), 36.3 (d, JC,P
=
2
1
136.1 Hz) ppm. MS (FAB): m/z (%) = 514 (67) [M + H]+, 513 (22),
287 (29), 280 (20), 279 (100), 262 (23), 201 (14), 185 (14), 183 (21),
155 (17), 138 (21), 137 (45), 120 (10), 107 (20), 91 (14), 90 (14), 89
(21), 77 (21). HRMS: calcd. for C28H2279BrNO2P [M + H]+
514.0566; found 514.0567.
Synthesis of N-Substituted and Unsubstituted 1,6-Methano[10]an-
nulene-3,4-dicarboximides (1b–1h and 6): The reactions of 2 with
phosphorane 8 under the conditions of Table 1 and Figure 1 gave
1b–1h and 6. The products were purified by silica gel chromatog-
raphy (hexane/EtOAc).
N-(4-Nitrophenyl)triphenylphosphoranylidenesuccinimide (8f): Col-
orless solid (68% yield), m.p. 144–146 °C. 1H NMR (500 MHz,
CDCl3): δ = 8.25 (d, J = 9.2 Hz, 2 H), 9.15 (d, J = 9.2 Hz, 2 H),
7.65 (m, 9 H), 7.57 (m, 6 H), 3.18 (s, 2 H) ppm. 13C NMR
N-Methyl-1,6-methano[10]annulene-3,4-dicarboximide (1b): Yellow
prisms (26.0 mg, 58%),[22] m.p. 169–170 °C (ref.[1a] 168–170 °C). 1H
NMR (400 MHz, CDCl3): δ = 8.25 (s, 2 H), 7.57 (m, 2 H), 7.33
(m, 2 H), 3.21 (s, 3 H), 0.18 (dt, J = 9.9, 1.2 Hz, 1 H), –0.21 (dt, J
= 9.9, 1.2 Hz, 1 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 170.4,
130.4, 129.9, 129.2, 128.7, 119.4, 35.8, 24.5 ppm.
(125 MHz, CDCl3): δ = 175.4 (d, 3J = 16.5 Hz), 168.4 (d, 2J =
4
16.2 Hz), 145.2, 140.2, 133.4 (d, 3J = 10.5 Hz), 133.0 (d, JC,P
=
2.5 Hz), 129.3 (d, 3J = 12.3 Hz), 126.2, 124.8 (d, 1J = 92.7 Hz),
123.8, 37.3 (d, 1J = 136.2 Hz), 36.8 (d, 3J = 13.1 Hz) ppm. MS
(FAB): m/z (%) = 481 (100) [M + H]+, 480 (24), 287 (32), 279 (57),
262 (31), 183 (29), 155 (16), 138 (18), 137 (39), 107 (21), 91 (19),
90 (16), 89 (24), 77 (25), 69 (23). HRMS: calcd. for C28H22N2O4P
[M + H]+ 481.1312; found 481.1315.
N-Ethyl-1,6-methano[10]annulene-3,4-dicarboximide (1c): Yellow
microcrystals (23.2 mg, 48%),[22] m.p. 164–166 °C (ref.[1a] 163–
1
165 °C). H NMR (400 MHz, CDCl3): δ = 8.25 (s, 2 H), 7.58 (m,
2 H), 7.32 (m, 2 H), 3.77 (q, J = 7.2 Hz, 2 H), 1.28 (t, J = 7.2 Hz,
3 H), 0.19 (dt, J = 9.8, 1.2 Hz, 1 H), –0.22 (dt, J = 9.8, 1.2 Hz, 1
H) ppm. 13C NMR (100 MHz, CDCl3): δ = 170.1, 130.4, 129.9,
129.2, 128.8, 119.4, 35.7, 33.4, 14.0 ppm.
N-(4-Iodophenyl)triphenylphosphoranylidenesuccinimide (8g): Color-
less solid (75% yield), m.p. 145–147 °C. 1H NMR (500 MHz,
CDCl3): δ = 7.70 (dt, J = 8.7, 2.3 Hz, 2 H), 7.64 (m, 9 H), 7.53 (m,
6 H), 7.26 (dt, J = 8.7, 2.3 Hz, 2 H), 3.14 (d, J = 2.3 Hz, 2 H) ppm.
3
13C NMR (125 MHz, CDCl3): δ = 175.76 (d, JC,P = 16.1 Hz),
N-(4-Methoxyphenyl)-1,6-methano[10]annulene-3,4-dicarboximide
(1d): Yellow microcrystals (37.3 mg, 58 %),[22] m.p. 216–218 °C
(ref.[1a] 217–218 °C). 1H NMR (400 MHz, CDCl3): δ = 8.35 (s, 2
H), 7.62 (m, 2 H), 7.36 (m, 4 H), 7.02 (dt, J = 9.0, 2.8 Hz, 2 H),
3.85 (s, 3 H), 0.22 (dt, J = 9.9, 1.2 Hz, 1 H), –0.16 (dt, J = 9.9,
1.2 Hz, 1 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 169.5, 159.3,
130.9, 130.1, 129.3, 128.3, 128.0, 124.8, 119.7, 114.5, 55.7,
35.6 ppm.
2
2
169.2 (d, JC,P = 15.8 Hz), 137.5, 133.9, 133.4 (d, JC,P = 10.4 Hz),
4
3
132.8 (d, JC,P = 2.6 Hz), 129.2 (d, JC,P = 12.2 Hz), 128.3, 125.2
1
2
1
(d, JC,P = 93.2 Hz), 91.4, 36.9 (d, JC,P = 10.4 Hz), 36.3 (d, JC,P
= 138.3 Hz) ppm. MS (FAB): m/z (%) = 562 (100) [M + H]+, 561
(46), 536 (38), 287 (39), 279 (94), 262 (32), 154 (53), 137 (33), 136
(49). HRMS: calcd. for C28H22NO2PI [M + H]+ 562.0427; found
562.0435.
N-(Biphenyl-4-yl)triphenylphosphoranylidenesuccinimide (8h): Col-
orless solid (71% yield), m.p. 160–162 °C. 1H NMR (500 MHz,
CDCl3): δ = 7.64 (m, 11 H), 7.54 (m, 10 H), 7.41 (t, J = 7.6 Hz, 2
H), 7.32 (tt, J = 7.6, 1.9 Hz, 1 H), 3.18 (d, J = 1.5 Hz, 2 H) ppm.
13C NMR (125 MHz, CDCl3): δ = 176.0 (d, 3JC,P = 16.1 Hz), 169.8
N-(4-Bromophenyl)-1,6-methano[10]annulene-3,4-dicarboximide
1
(1e): Yellow microcrystals (48.7 mg, 65%)[22] m.p. 210–211 °C. H
NMR (400 MHz, CDCl3): δ = 8.37 (s, 2 H), 7.64 (m, 2 H), 7.62
(dt, J = 8.8, 2.4 Hz, 2 H), 7.39 (dt, J = 8.8, 2.4 Hz, 2 H), 7.36 (m,
2 H), 0.20 (dt, J = 9.8, 1.2 Hz, 1 H), –0.14 (dt, J = 9.8, 1.2 Hz, 1
H) ppm. 13C NMR (100 MHz, CDCl3): δ = 168.9, 132.3, 131.3,
131.2, 130.3, 129.5, 128.04, 127.99, 121.8, 119.9, 35.6 ppm. IR
2
2
(d, JC,P = 15.6 Hz), 141.1, 139.5, 133.4 (d, JC,P = 10.1 Hz), 132.7
4
3
(d, JC,P = 2.4 Hz), 129.23, 129.18 (d, JC,P = 12.8 Hz), 128.6,
1
2
(KBr): ν
= 1750 (s), 1374 (s) cm–1. MS (EI, 70 eV): m/z (%) =
127.3, 127.2, 127.0, 126.8, 125.4 (d, JC,P = 92.0 Hz), 37.1 (d, JC,P
˜
max
1
367 (62) [M]+, 365 (63) [M]+, 323 (15), 321 (16), 286 (10), 227 (10),
1 6 8 ( 4 3 ) , 1 4 3 ( 1 3 ) , 1 4 1 ( 1 2 ) , 1 4 0 ( 1 0 0 ) , 1 6 9 ( 7 1 ) .
C19H12BrNO2·0.2H2O (369.8): calcd. C 61.71, H 3.38, N 3.79;
found C 61.55, H 3.54, N 3.78.
= 12.7 Hz), 36.2 (d, JC,P = 137.0 Hz) ppm. MS (FAB): m/z (%) =
512 (100) [M + H]+, 511 (56), 510 (27), 288 (18), 287 (63), 279 (37),
262 (28), 185 (15), 183 (25), 154 (15). HRMS: calcd. for
C34H27NO2P [M + H]+ 512.1774; found 512.1775.
Triphenylphosphoranylidenesuccinimide (8i): Colorless solid (64%
yield), m.p. 194–196 °C (ref.[8a] 220 °C). 1H NMR (500 MHz,
CDCl3): δ = 7.62 (m, 9 H), 7.53 (m, 6 H), 7.21 (br, 1 H), 3.03 (d,
J = 1.1 Hz, 2 H) ppm. 13C NMR (125 MHz, CDCl3): δ = 177.7 (d,
N-(4-Nitrophenyl)-1,6-methano[10]annulene-3,4-dicarboximide (1f):
Bright yellow microcrystals (47.9 mg, 72 %)[22] m.p. 271–272 °C
(ref.[1a] 268–270 °C). 1H NMR (400 MHz, CDCl3): δ = 8.41 (s, 2
H), 8.37 (dt, J = 9.2, 2.5 Hz, 2 H), 7.82 (dt, J = 9.2, 2.5 Hz, 2 H),
7.67 (m, 2 H), 7.39 (m, 2 H), 0.19 (dt, J = 9.9, 1.3 Hz, 1 H), –0.10
(dt, J = 9.9, 1.2 Hz, 1 H) ppm. 13C NMR (100 MHz, CDCl3): δ =
168.4, 146.4, 138.1, 131.6, 130.5, 129.7, 127.6, 126.5, 124.5, 120.1,
35.5 ppm.
2
2
3JC,P = 16.7 Hz), 170.7 (d, JC,P = 14.3 Hz), 133.4 (d, JC,P
=
10.7 Hz), 132.8 (d, 4JC,P = 2.4 Hz), 129.2 (d, 3JC,P = 13.1 Hz), 125.4
(d, JC,P = 91.8 Hz), 38.3 (d, JC,P = 9.5 Hz), 36.7 (d, JC,P
1
2
1
=
135.9 Hz) ppm.
N-Phenyl-1,6-methano[10]annulene-3,4-dicarboximide (1a): A mix-
ture of 2 (29.6 mg, 0.200 mmol) and phosphorane 8a (131 mg,
N-(4-Iodophenyl)-1,6-methano[10]annulene-3,4-dicarboximide (1g):
Yellow plates (50.4 mg, 61 %)[22] m.p. 225–227 °C. 1H NMR
5982
www.eurjoc.org
© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2014, 5976–5985

Synthesis of 1,6-Methano[10]annulene-3,4-dicarboximides
(500 MHz, CDCl3): δ = 8.36 (s, 2 H), 7.83 (dt, J = 6.9, 2.3 Hz, 2
H), 7.64 (m, 2 H), 7.36 (m, 2 H), 7.26 (dt, J = 6.9, 2.3 Hz, 2 H),
0.19 (dt, J = 9.8, 1.2 Hz, 1 H), –0.14 (dt, J = 9.8, 1.1 Hz, 1 H)
ppm. 13C NMR (125 MHz, CDCl3): δ = 168.8, 138.3, 132.0, 131.2,
(s, 2 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 192.0, 173.4,
170.6, 147.9, 140.5, 139.7, 137.1, 136.4, 136.1, 134.5, 132.2, 132.0,
131.8, 129.8, 129.3, 128.7, 128.4, 126.6, 123.8, 34.2, 22.3 ppm. IR
(KBr): ν
= 1765 (m), 1703 (vs), 1666 (s), 1631 (m), 1386 (s),
˜
max
130.3, 129.5, 128.2, 128.0, 119.9, 93.3, 35.6 ppm. IR (KBr): ν
=
1375 (s), 1178 (s), 755 (s), 741 (m), 701 (s) cm–1. MS (EI, 70 eV):
˜
max
1766 (s), 1711 (s), 1698 (vs), 1153 (s), 1137 (s), 815 (s), 772 (s), 754 m/z (%) = 355 (100) [M]+, 337 (49), 293 (21), 235 (18), 207 (41),
(s) cm–1. MS (EI, 70 eV): m/z (%) = 413 (100) [M]+, 369 (11), 242
(15), 168 (25), 140 (56). HRMS: calcd. for C19H12INO2 [M]+
412.9913; found. 412.9911.
178 (69), 165 (30), 149 (26), 139 (16), 91 (24), 69 (26), 57 (39).
HRMS: calcd. for C23H17N2O3 [M]+ 355.1208; found 355.1212.
Similarly, the products 12b–12c, 12e, 13b, 13c, 14, and a mixture of
15 and 16 (Schemes 3–5) were obtained.
N-(Biphenyl-4-yl)-1,6-methano[10]annulene-3,4-dicarboximide (1h):
Light yellow prisms (39.7 mg, 55%),[22] m.p. 232–237 °C. 1H NMR
(400 MHz, CDCl3): δ = 8.39 (s, 2 H), 7.72 (dt, J = 8.4, 1.7 Hz, 2
H), 7.64 (m, 2 H), 7.62 (dm, 2 H), 7.56 (dt, J = 8.4, 1.7 Hz, 2 H),
7.46 (tm, J = 7.2 Hz, 2 H), 7.37 (m, 3 H), 0.24 (d, J = 9.9 Hz, 1
H), –0.14 (d, J = 9.9 Hz, 1 H) ppm. 13C NMR (100 MHz, CDCl3):
δ = 169.3, 141.1, 140.6, 131.4, 131.1, 130.3, 129.4, 129.0, 128.3,
6-Formyl-1-(N-methylsuccinimidylidenemethyl)-3,4-benzocyclo-
hepta-1,3,5-triene (12b): Yellow prisms (78.3 mg, 53%),[23] m.p.
1
188–190 °C. H NMR (400 MHz, CDCl3): δ = 9.59 (s, 1 H), 7.55
(d, J = 7.3 Hz, 1 H), 7.42–7.49 (m, 4 H), 7.29 (td, J = 2.0, 0.8 Hz,
1 H), 7.05 (d, J = 0.8 Hz, 1 H), 3.69 (d, J = 2.0 Hz, 2 H), 3.14 (s,
2 H), 3.11 (s, 3 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 191.8,
174.3, 171.6, 147.7, 139.9, 139.6, 137.0, 136.0, 135.2, 134.4, 131.8,
128.0, 127.7, 127.4, 126.9, 119.8, 35.6 ppm. IR (KBr): νmax = 1763
˜
(s), 1704 (vs), 1518 (s), 1488 (s), 1154 (s), 765 (s) cm–1. MS (EI,
70 eV): m/z (%) = 363 (68) [M]+, 319 (10), 286 (7), 207 (10), 168
(43), 152 (23), 140 (100), 139 (68), 86 (11), 84 (28), 69 (14).
C25H17NO2·0.2H2O (367.0): calcd. C 81.81, H 4.78, N 3.82; found
C 81.80, H 4.86, N 3.74.
131.7, 129.6, 128.1, 124.2, 25.0, 33.8, 22.1 ppm. IR (KBr): ν
=
˜
max
1759 (s), 1694 (vs), 1665 (vs), 1628 (s) cm–1. MS (EI, 70 eV): m/z
(%) = 293 (100) [M]+, 275 (17), 264 (19), 208 (25), 207 (18), 206
(15), 190 (14), 189 (11), 181 (16), 180 (31), 179 (93), 178 (74), 177
(16), 176 (17), 169 (25), 165 (28), 152 (20), 151 (12), 141 (13), 139
(12), 137 (11), 115 (13), 89 (15). C18H15NO3·0.2H2O (296.9): calcd.
C 72.81, H 5.23, N 4.72; found C 72.81, H 5.31, N 4.69.
1,6-Methano[10]annulene-3,4-dicarboximide (6): Yellow microcrys-
tals (25.9 mg, 62%),[22] m.p. 249–251 °C (ref.[1a] 248–250 °C). 1H
NMR (400 MHz, CDCl3): δ = 8.27 (s, 2 H), 7.96 (br, 1 H), 7.61
(m, 2 H), 7.34 (m, 2 H), 0.10 (dt, J = 9.9, 1.3 Hz, 1 H), –0.20 (dt,
J = 9.9, 1.1 Hz, 1 H) ppm. 13C NMR (100 MHz, CDCl3): δ =
169.9, 130.8, 130.3, 129.4, 129.1, 119.5, 35.4 ppm.
1,6-Bis(N-methylsuccinimidylidenemethyl)-3,4-benzocyclohepta-
1,3,5-triene (13b): Yellow solid (53.2 mg, 27%),[23] m.p. 270–273 °C.
1H NMR (400 MHz, CDCl3): δ = 7.45–7.37 (m, 4 H), 7.29 (t, J =
2.2 Hz, 2 H), 7.00 (s, 2 H), 3.52 (d, J = 2.2 Hz, 4 H), 3.11 (s, 6 H),
2.90 (s, 2 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 173.6, 170.9,
136.3, 136.0, 134.29, 134.28, 131.4, 128.0, 124.0, 34.1, 32.9,
6H-Cyclohepta[b]thiophene-5,7-dicarbaldehyde (11): A 50% aque-
ous solution of pentanedial (6.00 g, 30.0 mmol) was added drop-
25.0 ppm. IR (KBr): ν
= 1758 (s), 1698 (vs), 1433 (s), 1277 (s)
˜
max
wise to
a solution of thiophene-2,3-dicarbaldehyde (2.80 g,
cm–1. MS (EI, 70 eV): m/z (%) = 388 (100) [M]+, 329 (19), 303 (15),
302 (13), 301 (11), 277 (12), 276 (23), 275 (13), 272 (10), 264 (30),
250 (11), 245 (13), 218 (18), 217 (24), 215 (38), 203 (22), 202 (32),
192 (18), 191 (25), 190 (13), 189 (17), 179 (43), 178 (40), 166 (11),
165 (26), 152 (17), 137 (17), 108 (14), 101 (12). C23H20N2O4·0.7H2O
(401.0): calcd. C 68.88, H 5.38, N 6.99; found C 68.99, H 5.37, N
7.00.
20.0 mmol) and piperidine (4.40 mL) in AcOH (25 mL) at 100 °C
under a nitrogen atmosphere. This mixture was heated at 120 °C
for 2 h and then cooled to room temperature. The resultant dark
brown mixture was diluted with water (300 mL) and extracted with
CHCl3 (100 mLϫ3). The combined organics layers were washed
with a saturated NaHCO3 aqueous solution and brine and dried
with Mg2SO4. The solvent was evaporated, and the residue was
crystallized from hexane/CHCl3 to give 11 (3.77 g, 92%) as yellow
needles, m.p. 194–196 °C. 1H NMR (400 MHz, CDCl3): δ = 9.59
(s, 1 H), 9.56 (s, 1 H), 7.64 (d, J = 5.2 Hz, 1 H), 7.50 (s, 1 H), 7.45
(s, 1 H), 7.30 (d, J = 5.2 Hz, 1 H), 3.29 (s, 2 H) ppm. 13C NMR
(100 MHz, CDCl3): δ = 191.2, 190.5, 140.7, 140.5, 139.3, 138.7,
6-Formyl-1-(N-ethylsuccinimidylidenemethyl)-3,4-benzocyclohepta-
1,3,5-triene (12c): Yellow prisms (74.5 mg, 48 %),[22] m.p. 186–
1
188 °C. H NMR (400 MHz, CDCl3): δ = 9.59 (s, 1 H), 7.54 (d, J
= 7.2 Hz, 1 H), 7.46 (m, 4 H), 7.29 (td, J = 2.2, 0.8 Hz, 1 H), 7.04
(s, 1 H), 3.94 (d, J = 2.2 Hz, 1 H), 3.68 (q, J = 7.2 Hz, 2 H), 3.14
(s, 2 H), 1.22 (t, J = 7.2 Hz, 3 H) ppm. 13C NMR (100 MHz,
CDCl3): δ = 191.9, 174.2, 171.4, 147.9, 139.9, 139.7, 137.2, 136.2,
135.2, 134.5, 132.0, 131.8, 129.7, 128.2, 124.4, 34.0, 28.3, 22.3,
134.4, 133.5, 130.4, 130.1, 18.1 ppm. IR (KBr): ν
= 1667 (vs),
˜
max
1615 (s), 1600 (vs), 1422 (s), 1410 (s), 1230 (s), 1215 (vs), 1169 (vs),
1127 (s), 948 (s), 888 (s), 758 (s) cm–1. MS (EI, 70 eV): m/z (%) =
204 (100) [M]+, 175 (72), 147 (76), 145 (13), 121 (10). HRMS calcd.
for C11H8O2S [M]+ 204.0245; found 204.0248. C11H8O2S (204.2)
calcd. C 64.69, H 3.95, S 15.70; found C 64.99, H 3.98, S 16.78.
13.3 ppm. IR (KBr): ν
= 1756 (vs), 1688 (vs), 1672 (vs), 1626
˜
max
(vs), 1439 (s), 1409 (s), 1398 (vs), 1381 (s), 1339 (vs), 1214 (vs),
1156 (vs), 1136 (vs), 1041 (s), 744 (s) cm–1. MS (EI, 70 eV): m/z (%)
= 307 (100) [M]+, 278 (13), 236 (13), 208 (43), 191 (11), 179 (100),
169 (45), 151 (31), 141 (20), 115 (16), 94 (16), 89 (37), 76 (27).
C19H17NO3·0.1H2O (309.1): calcd. C 73.82, H 5.61, N 4.35; found
C 73.75, H 5.61, N, 4.45.
Reaction of 3,4-Benzocyclohepta-1,3,5-triene-1,6-dicarbaldehyde (9)
with Phosphoranes
8 in AcOH: A mixture of 9 (100 mg,
0.505 mmol) and (220 mg, 0.505 mmol) in AcOH (4 mL) under a
nitrogen atmosphere was heated to reflux with an oil bath for 18
h, and then the solvent was removed under vacuum. The residue
was carefully poured into a mixture of cold NaHCO3 aqueous solu-
1,6-Bis(N-ethylsuccinimidylidenemethyl)-3,4-benzocyclohepta-1,3,5-
triene (13c): Yellow solid (22.8 mg, 11%),[22] m.p. 248–252 °C. 1H
tion and CHCl3 and extracted with CHCl3 (15 mLϫ3). The com- NMR (400 MHz, CDCl3): δ = 7.41 (m, 4 H), 7.28 (t, J = 2.1 Hz,
bined organic layers were washed with brine and dried with
Mg2SO4. The solvent was evaporated, and the residue was purified
by silica gel chromatography (CHCl3/EtOAc 70:30) to give 12a
(41.3 mg, 23%) as yellow microcrystals, m.p. 195–197 °C. 1H NMR
(400 MHz, CDCl3): δ = 9.62 (s, 1 H), 7.56 (d, J = 7.2 Hz, 1 H),
2 H), 6.99 (s, 2 H), 3.68 (q, J = 7.2 Hz, 4 H), 3.51 (d, J = 2.1 Hz,
4 H), 2.90 (s, 2 H), 1.23 (t, J = 7.2 Hz, 6 H) ppm. 13C NMR
(100 MHz, CDCl3): δ = 173.4, 170.6, 136.2, 136.0, 134.1, 134.2,
131.4, 127.9, 124.1, 34.1, 33.9, 32.9, 13.1 ppm. IR (KBr): ν
=
˜
max
1763 (s), 1700 (vs), 1630 (s), 1399 (s), 1342 (s) cm–1. MS (EI, 70 eV):
7.51–7.36 (m, 10 H), 7.10 (s, 1 H), 4.16 (d, J = 2.0 Hz, 2 H), 3.19 m/z (%) = 416 (100) [M]+, 371 (13), 343 (19), 317 (16), 290 (42),
5983
Eur. J. Org. Chem. 2014, 5976–5985
© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org

M. Oda et al.
FULL PAPER
278 (36), 264 (13), 244 (66), 215 (58), 202 (55), 192 (77), 179 (99),
165 (51), 151 (41), 139 (17), 123 (46), 108 (96), 95 (63), 84 (71), 71
(56). C25H24N2O4·0.2H2O (420.1): calcd. C 71.48, H 5.85, N 6.67;
found C 71.24, H 5.86, N 6.65.
70 eV): m/z (%) = 337 (100) [M]+, 293 (34), 292 (16), 278 (7), 217
(17), 190 (62), 189 (60). C23H15NO2·0.1H2O (339.2): calcd. C 81.45,
H 4.52, N 4.13; found C 71.49, H 4.51, N 4.15.
Similarly, the products 17b, 17c, 17e, 18, 19a, and 19b (Schemes 3–
5 and Table 2) were obtained.
6-Formyl-1-[N-(4-bromophenyl)succinimidylidenemethyl]-3,4-benzo-
cyclohepta-1,3,5-triene (12e): Yellow prisms (44.4 mg, 20%),[22] m.p.
244–246 °C. H NMR (500 MHz, CDCl3): δ = 9.61 (s, 1 H), 7.61
(m, 2 H), 7.56 (d, J = 7.5 Hz, 1 H), 7.48 (m, 4 H), 7.41 (dt, J =
1.9, 0.9 Hz, 1 H), 7.10 (s, 1 H), 4.16 (d, J = 2.0 Hz, 2 H), 3.17 (s,
2 H) ppm. 13C NMR (125 MHz, CDCl3): δ = 192.0, 173.0, 170.2,
147.9, 140.8, 139.6, 137.0, 136.8, 136.0, 134.5, 132.4, 132.0, 131.9,
131.2, 129.8, 128.4, 128.1, 123.4, 122.4, 34.1, 22.2 ppm. IR (KBr):
N-Methyl-2,7-methanobenzo[10]annulene-4,5-dicarboximide (17b):
Yellow prisms (19.3 mg, 70% based on 12b),[24] m.p. 226–228 °C.
1H NMR (400 MHz, CDCl3): δ = 8.28 (t, J = 1.1 Hz, 2 H), 8.01
(m, 2 H), 7.60 (m, 2 H), 7.43 (t, J = 1.1 Hz, 2 H), 3.20 (s, 3 H),
1.43 (dt, J = 8.4, 1.0 Hz, 1 H), 0.35 (dt, J = 8.4, 1.0 Hz, 1 H) ppm.
13C NMR (100 MHz, CDCl3): δ = 169.2, 135.5, 134.8, 131.6, 128.4,
128.1, 127.5, 126.8, 32.3, 24.5 ppm. IR [attenuated total reflectance
1
= 1749 (m), 1687 (vs) cm–1. MS (EI, 70 eV): m/z (%)
ν
max = 1703 (s), 1672 (s) cm–1. MS (EI, 70 eV): m/z (%) = 435 (100)
˜
(ATR)]: ν
˜
max
[M]+, 433 (99) [M]+, 236 (16), 235 (22), 234 (13), 208 (34), 207 (31),
206 (19), 181 (12), 180 (22), 179 (78), 178 (75), 177 (14), 176 (11),
170 (12), 169 (33), 165 (21), 152 (13), 141 (10). HRMS: calcd. for
C23H1679BrNO3 [M]+ 433.0314; found 433.0310.
= 275 (100) [M]+, 274 (21), 190 (75), 189 (51), 95 (18). HRMS:
calcd. for C18H13NO2 [M]+ 275.0946, found 275.0939.
N-Ethyl-2,7-methanobenzo[10]annulene-4,5-dicarboximide (17c):
Yellow microcrystals (24.7 mg, 85% based on 12c),[24] m.p. 175–
178 °C. 1H NMR (400 MHz, CDCl3): δ = 8.28 (t, J = 1.2 Hz, 2 H),
8.01 (m, 2 H), 7.60 (m, 2 H), 7.43 (br s, 2 H), 3.76 (q, J = 7.2 Hz,
2 H), 1.44 (dt, J = 10.6, 1.1 Hz, 1 H), 1.28 (t, J = 7.2 Hz, 3 H),
0.35 (dt, J = 10.6, 1.3 Hz, 1 H) ppm. 13C NMR (100 MHz, CDCl3):
δ = 169.1, 135.5, 135.0, 131.8, 128.6, 128.2, 127.9, 126.9, 33.6, 32.4,
1-Formyl-6-(N-methylsuccinimidylidenemethyl)naphtho[2,3:3,4]cy-
clohepta-1,3,5-triene (14): Yellow prisms (77.6 mg, 46%),[23] m.p.
1
261–265 °C. H NMR (400 MHz, CDCl3): δ = 9.62 (s, 1 H), 8.03
(s, 1 H), 7.90 (m, 3 H), 7.58 (m, 3 H), 7.36 (td, J = 1.8, 0.8 Hz, 1
H), 7.00 (s, 1 H), 3.93 (d, J = 1.8 Hz, 2 H), 3.28 (s, 2 H), 3.12 (s,
3 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 191.6, 174.2, 171.5,
148.9, 141.2, 140.6, 137.4, 135.9, 133.6, 133.4, 132.5, 132.4, 132.0,
131.7, 128.3, 128.24, 128.16, 127.7, 123.8, 34.0, 24.9, 22.6 ppm. IR
13.7 ppm. IR (ATR): ν
= 1754 (s), 1693 (vs), 1402 (s), 740 (s)
˜
max
cm–1. MS (EI, 70 eV): m/z (%) = 289 (100) [M]+, 274 (75), 261 (26),
247 (12), 218 (16), 190 (91), 187 (11), 123 (14), 109 (14), 94 (80),
83 (24). C19H15NO2·0.1H2O (291.1): calcd. C 78.39, H 5.26, N 4.81;
found C 78.77, H 5.31, N 4.77.
(KBr): νmax = 1760 (s), 1686 (vs), 1670 (vs), 1645 (s), 1632 (s), 1436
˜
(s), 1275 (s) cm–1. MS (EI, 70 eV): m/z (%) = 343 (100) [M]+, 229
(64), 228 (86), 226 (33), 215 (26), 202 (28). HRMS: calcd. for
C22H17NO3 [M]+ 334.1208; found 334.1206. C22H17NO3 (343.4):
calcd. C 76.95, H 4.99, N 4.08; found C 76.61, H 5.21, N 4.07.
N-(4-Bromophenyl)-2,7-methanobenzo[10]annulene-4,5-dicarboxim-
ide (17e): Yellow microcrystals (13.5 mg, 33% based on 12e),[24]
1
m.p. 216–219 °C. H NMR (500 MHz, CDCl3): δ = 8.42 (s, 2 H),
8.04 (m, 2 H), 7.63 (m, 4 H), 7.51 (s, 2 H), 7.38 (dt, J = 8.6, 1.7 Hz,
2 H), 1.44 (d, J = 10.7 Hz, 1 H), 0.36 (d, J = 10.7 Hz, 1 H) ppm.
13C NMR (125 MHz, CDCl3): δ = 167.8, 136.9, 134.8, 132.2, 131.8,
131.1, 128.6, 128.4, 128.0, 127.0, 127.0, 122.0, 32.1 ppm. IR (ATR):
Mixture of 5-Formyl-7-(N-methylsuccinimidylidenemethyl)-6H-cy-
clohepta[b]thiophene (15) and 7-Formyl-5-(N-methylsuccinimidyl-
idenemethyl)-6H-cyclohepta[b]thiophene (16): Yellow solid (98.9 mg,
1
66%),[23] m.p. 173–189 °C. H NMR (400 MHz, CDCl3): δ = 9.58
ν
max = 1763 (m), 1708 (s), 1379 (s), 799 (m), 735 (m) cm–1. MS (EI,
˜
(s, 1 H), 9.56 (s, 1 H), 7.60 (d, J = 5.2 Hz, 1 H), 7.53 (s, 1 H), 7.49
(s, 1 H), 7.48 (s, 1 H), 7.27 (m, 3 H), 7.19 (d, J = 5.2 Hz, 1 H),
7.16 (s, 1 H), 7.10 (s, 1 H), 4.02 (m, 4 H), 3.22 (m, 4 H), 3.11 (s, 6
H) ppm. 13C NMR (100 MHz, CDCl3): δ = 192.1, 191.4, 174.33,
174.28, 171.5, 171.4, 143.6, 141.7, 141.3, 139.5, 138.3, 137.8, 134.9,
134.3, 134.1, 133.2, 132.2, 131.9, 130.5, 130.21, 130.19, 130.1,
129.5, 127.9, 125.0, 124.8, 34.0, 33.9, 25.0, 24.9, 23.4, 23.3 ppm. IR
70 eV): m/z (%) = 417 (100) [M]+, 415 (98) [M]+, 373 (18), 372 (10),
371 (18), 218 (11), 217 (19), 191 (13), 190 (76), 189 (66), 168 (21).
HRMS: calcd. for C23H1479BrNO2 [M]+ 415.0208; found 415.0206.
N-Methyl-2,7-methanonaphtho[2,3][10]annulene-4,5-dicarboximide
(18): Yellow microplates (10.2 mg, 32% based on 14),[24] m.p. 240–
1
243 °C. H NMR (400 MHz, CDCl3): δ = 8.50 (s, 2 H), 8.22 (t, J
= 1.2 Hz, 2 H), 8.03 (m, 2 H), 7.61 (m, 2 H), 7.38 (s, 2 H), 3.20 (s,
3 H), 1.80 (dt, J = 10.9, 1.2 Hz, 1 H), 1.14 (dt, J = 10.9, 1.4 Hz, 1
H) ppm. 13C NMR (100 MHz, CDCl3): δ = 169.1, 135.8, 133.5,
132.3, 131.5, 130.7, 128.0, 127.8, 127.0, 126.8, 32.4, 24.6 ppm. IR
(KBr): ν
= 1760 (s), 1693 (vs), 1664 (s) 1432 (s), 1382 (s), 1280
˜
max
(s) cm–1. MS (EI, 70 eV): m/z (%) = 299 (100) [M]+, 270 (24), 214
(19), 213 (17), 185 (78), 171 (13), 139 (11). HRMS: calcd. for
C16H13NO2S [M]+ 299.0616; found 299.0616.
(ATR): ν
= 1751 (m), 1690 (vs) cm–1. MS (EI, 70 eV): m/z (%)
˜
max
N-Phenyl-2,7-methanobenzo[10]annulene-4,5-dicarboximide (17)
from 12: A mixture of 12a (35.5 mg, 0.100 mmol) and NaOMe
(5.4 mg, 0.10 mmol) in MeOH (4 mL) under a nitrogen atmosphere
was gently heated to reflux with an oil bath for 24 h. The resultant
reaction mixture was carefully poured into a 0.1 m HCl aqueous
solution and extracted with CHCl3 (10 mLϫ3). The combined or-
ganic layers were washed with a saturated NaHCO3 aqueous solu-
tion and brine and dried with Mg2SO4. The solvent was evapo-
rated, and the residue was purified by silica gel chromatography
(CHCl3) to give 17a (28.7 mg, 85%) as yellow microcrystals, m.p.
= 325 (100) [M]+, 324 (31), 239 (56), 237 (17). C22H15NO2 (325.4):
calcd. C 81.21, H 4.65, N 4.30; found C 81.30, H 4.94, N 4.40.
N-Phenyl-2,7-methanothieno[2,3][10]annulene-4,5-dicarboximide
(19a): Yellow microcrystals (29.5 mg, 86% based on 11),[24] m.p.
1
140–141 °C. H NMR (500 MHz, CDCl3): δ = 8.53 (m, 1 H), 8.44
(m, 1 H), 7.95 (s, 1 H), 7.86 (s, 1 H), 7.76 (d, J = 5.5 Hz, 1 H),
7.60 (d, J = 5.5 Hz, 1 H), 7.56–7.46 (m, 4 H), 7.40 (tt, J = 7.1,
1.6 Hz, 1 H), 0.74 (dm, J = 10.6 Hz, 1 H), –0.10 (dt, J = 10.6,
1.0 Hz, 1 H) ppm. 13C NMR (125 MHz, CDCl3): δ = 168.7 (2 C),
141.8, 139.9, 135.2, 134.4, 132.2, 129.2, 128.7, 128.2, 128.1, 128.0,
1
219–222 °C. H NMR (500 MHz, CDCl3): δ = 8.43 (t, J = 1.2 Hz,
127.9, 126.6, 126.2, 124.2, 121.6, 120.3, 33.2 ppm. IR (ATR): ν
˜
max
2 H), 8.04 (m, 2 H), 7.63 (m, 2 H), 7.53–7.49 (m, 4 H), 7.46 (dt, J
= 7.1, 1.6 Hz, 2 H), 7.41 (tt, J = 7.1, 1.6 Hz, 1 H), 1.47 (dt, J =
10.7, 1.1 Hz, 1 H), 0.37 (td, J = 10.7, 1.3 Hz, 1 H) ppm. 13C NMR
(125 MHz, CDCl3): δ = 168.2, 136.7, 134.9, 132.2, 131.9, 129.2,
= 1754 (s), 1701 (s) cm–1. MS (EI, 70 eV): m/z (%) = 343 (100)
[M]+, 342 (15), 299 (34), 298 (16), 223 (12), 196 (49), 195 (40).
HRMS: calcd. for C21H13NO2S [M]+ 343.0667; found 343.0666.
128.6, 128.5, 128.3, 127.3, 127.0, 126.7, 32.3 ppm. IR (KBr): ν
N-Methyl-2,7-methanothieno[2,3][10]annulene-4,5-dicarboximide
(19b): Golden yellow microcrystals (28.5 mg, 83% based on a mix-
˜
max
= 1760 (m), 1698 (vs), 1379 (s), 1152 (s), 741 (s) cm–1. MS (EI,
5984
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© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2014, 5976–5985

Synthesis of 1,6-Methano[10]annulene-3,4-dicarboximides
ture of 15 and 16),[24] m.p. 186–188 °C. 1H NMR (400 MHz,
CDCl3): δ = 8.39 (m, 1 H), 8.31 (m, 1 H), 7.88 (s, 1 H), 7.80 (s, 1
H), 7.74 (d, J = 5.5 Hz, 1 H), 7.58 (d, J = 5.5 Hz, 1 H), 3.21 (s, 3
H), 0.73 (dt, J = 10.6, 1.2 Hz, 1 H), –0.11 (dt, J = 10.6, 1.2 Hz, 1
H) ppm. 13C NMR (125 MHz, CDCl3): δ = 168.94, 168.92, 140.7,
139.4, 133.7, 132.9, 129.2, 128.1, 128.0, 127.8, 126.2, 124.2, 120.7,
[4]
[5]
R. Neidlein, G. Schröder, Chem. Ber. 1992, 125, 2225–2232.
S. Kuroda, Y. Terada, T. Miyatake, Y. Horino, T. Abe, Y. Fuji-
wara, M. Oda, Tetrahedron Lett. 2011, 52, 7071–7074.
C. S. Sarmah, J. C. S. Kataky, Ind. J. Chem. Sect. B 1993, 32,
1449–1450.
S. Kuroda, M. Oda, S. Zuo, R. Miyatake, K. Kanayama,
S. I. M. Shah, S. Furuta, R. Miyatake, M. Kyougoku, Tetrahe-
dron Lett. 2001, 42, 6345–6348.
a) E. Hedaya, T. Theodoropulos, Tetrahedron 1968, 24, 2241–
2254; b) M. Koszytkowska-Stawiñska, W. Sas, J. Chem. Res.
Synop. 1999, 694–695; c) G. Doorakian, D. Schmidt, US
3843605A, 1974.
L. Lepage, Y. Lepage, Bull. Soc. Chim. Fr. 1988, 591–594.
Dicarbaldehyde 11 was obtained by condensation of thio-
phene-2,3-dicarbaldehyde and pentanedial; see the Experimen-
tal Section for details.
Although the structures of 12, 14, 15, and 16 in Schemes 3–5
are drawn as the rotational isomer shown at the left side of
Figure 3 for convenience, the crystal structures of 12e and 14
were revealed to be the other isomer shown at the right side in
Figure 3. The two rotational isomers should be in equilibrium
in solution.
For chemical shift difference between the vinylic protons of the
(E) and (Z) isomers, see a typical example below. For the syn-
thesis of these products, see: S. H. Hung, J. H. Kim, J. H. Lee,
Bull. Korean Chem. Soc. 2004, 25, 1088–1090.
[6]
[7]
119.4, 32.8, 24.1 ppm. IR (ATR): ν
= 1757 (s), 1698 (vs) cm–1.
˜
max
MS (EI, 70 eV): m/z (%) = 343 (100) [M]+, 342 (15), 299 (34), 298
(16), 223 (12), 196 (49), 195 (40). HRMS calcd. for C16H11NO2S
[M]+ 281.0510; found; 281.0504. C16H11NO2S (281.3): calcd. C
68.31, H 3.94, N 4.98, S 11.40; found C 68.62, H 3.98, N 4.98, S
12.00.
[8]
[9]
[10]
X-ray Crystallographic Analysis: The diffraction measurements
were conducted with a Rigaku R-AXIS RAPID diffractometer.
The crystal data for 1a are as follows: monoclinic, space group P21/
c (no. 14), a = 9.2687(2) Å, b = 14.8940(3) Å, c = 10.1047(2) Å, β
= 94.1965(9)°, V = 1391.19(5) Å3, Z = 4, μ = 7.192 cm–1, R =
0.0454, wR2 = 0.1090, R1 = 0.0401 [IϾ2.0σ(I)], and S = 1.082.
The crystal data for 12e are as follows: monoclinic, space group
P21 (no. 4), a = 6.8512(2) Å, b = 20.2644(4) Å, c = 13.6466(3) Å,
β = 92.8941(7)°, V = 1892.22(6) Å3, Z = 4, μ = 31.659 cm–1, R =
0.0387, wR2 = 0.0966, R1 = 0.0364 [IϾ2.0σ(I)], and S = 1.0569.
[11]
[12]
¯
The crystal data for 14 are as follows: triclinic, space group P1
(no. 1), a = 6.0211(1) Å, b = 12.4895(3) Å, c = 21.5614(5) Å, α =
89.983(2)°, β = 89.999(2)°, γ = 81.989(2)°, V = 1605.60(6) Å3, Z =
4, μ = 7.672 cm–1, R = 0.0743, wR2 = 0.1752, R1 = 0.0676
[IϾ2.0σ(I)], and S = 1.007. The crystal data for 17b are as follows:
monoclinic, space group P21/c (no. 14), a = 8.9068(3) Å, b =
12.5694(4) Å, c = 12.3307(4) Å, β = 107.233(2)°, V = 1318.50(8) Å3,
Z = 4, μ = 7.316 cm–1, R = 0.0699, wR2 = 0.1564, R1 = 0.0622
[IϾ2.0σ(I)], and S = 1.143. The crystal data for 18 are as follows:
orthorhombic, space group P212121 (no. 19), a = 6.5236(2) Å, b =
8.7190(3) Å, c = 27.3097(9) Å, V = 1553.37(8) Å3, Z = 4, μ =
7.140 cm–1, R = 0.0588, wR2 = 0.1298, R1 = 0.0543 [IϾ2.0σ(I)],
and S = 1.122. CCDC-988796 (for 1a), -988798 (for 12e), -988797
(for 14), -988795 (for 17b), and -988794 (for 18) contain the supple-
mentary crystallographic data for this paper. These data can be
obtained free of charge from The Cambridge Crystallographic
Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
[13]
[14]
For examples of the X-ray structural analysis of cycloheptatri-
enes, see:W. Bauer, J. Daub, G. Maas, M. Michna, K. M. Rapp,
J. J. Stezowski, Chem. Ber. 1982, 115, 99–118; J. Stegemann,
H. J. Lindner, Acta Crystallogr., Sect. B 1980, 36, 3146–3148;
J. E. Weidenborner, R. B. Larrabee, A. L. Bednowitz, J. Am.
Chem. Soc. 1972, 94, 4140–4144; R. E. Davis, A. Tulinsky, J.
Am. Chem. Soc. 1966, 88, 4583–4588.
E. Vogel, H. D. Roth, Angew. Chem. Int. Ed. Engl. 1964, 3,
228–229; Angew. Chem. 1964, 76, 145.
[15] For the crystallographic data of 1,6-methano[10]annulene, see:
R. Bianchi, T. Piliati, M. Simonetta, Acta Crystallogr., Sect. B
1979, 35, 2161–2165.
Supporting Information (see footnote on the first page of this arti-
cle): 1H and 13C NMR spectra of new compounds and UV/Vis
absorption and emission spectra of 1b, 17b, 18, and 19b.
[16] C. S. Sarmah, J. C. S. Kataky, Ind. J. Chem. Sect. B 1993, 32,
1149–1150.
[17] a) S. Kuroda, S. Zuo, M. Oda, A. Fukuta, T. Kajioka, T. Saito,
S. Furuta, H. Tsukumo, R. Miyatake, S. Tomoda, C. Hayak-
awa, H. Nozawa, Bull. Chem. Soc. Jpn. 2000, 73, 1659–1671;
b) S. Kuroda, T. Kajioka, A. Fukuta, N. C. Thanh, Y. Zhang,
R. Miyatake, M. Mouri, S. Zuo, M. Oda, Mini-Rev. Org. Chem.
2007, 4, 31–49.
[18] The UV/Vis absorption and emission spectra of 1b, 17b, 18,
and 19b are shown in the Supporting Information.
[19] A. Mallouli, Y. Lepage, Synthesis 1980, 689.
[20] E. Vogel, M. Schäfer-Ridder, DE 2851790, 1980.
[21] No spectroscopic data of 8d are reported in ref.[8b]
[22] The actual quantity of the product and its yield in a reaction
with 0.2 mmol of the dicarbaldehyde.
Acknowledgments
The authors thank the Department of Chemistry, Shinshu Univer-
sity for financial support and Ms. Yurie Fujiwara for her technical
assistance to prepare single crystals for X-ray analysis.
[1] a) S. Kuroda, N. Tamura, R. Miyatake, N. Matsumoto, Y. Ho-
rio, D. Miyawaki, M. Oda, Heterocycles 2011, 83, 789–796; b)
S. Kuroda, N. Matsumoto, Y. Zhang, T. Abe, Y. Horio, Y. Fuji-
wara, M. Oda, Heterocycles 2012, 84, 275–7281.
[2] F. Jin, J. Liu, H. Chen, S. Zuo, Beijing Huagong Daxue Xuebao,
Ziran Kexueban 2010, 37, 28–31.
[3] a) E. Vogel, R. Feldman, H. Düwel, Tetrahedron Lett. 1970,
11, 1941–1944; b) E. Vogel, H. M. Deger, J. Somdroek, J. Palm,
A. Wagner, J. Lex, Angew. Chem. Int. Ed. Engl. 1980, 19, 41–
43; Angew. Chem. 1980, 92, 43; c) E. Vogel, Pure Appl. Chem.
1982, 54, 1015–1039.
[23] The actual quantity of the product and its yield in a reaction
with 0.505 mmol of the dicarbaldehyde.
[24] The actual quantity of the product and its yield in a reaction
with 0.1 mmol of the dicarbaldehyde.
Received: June 19, 2014
Published Online: July 28, 2014
Eur. J. Org. Chem. 2014, 5976–5985
© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
5985