Syntheses of dihydropyrene-cyclophanediene negative photochromes containing internal alkenyl and alkynyl groups and comparison of their photochemical and thermochemical properties

Article abstract of DOI:10.1021/jo4024446

Synthesis of a variety of 8,16-disubstituted-anti-[2.2]- metacyclophanedienes (CPD) with alkenyl and alkynyl internal (8,16) groups is described together with their analogous dihydropyrenes (DHP). Eyring and Arrhenius parameters were determined for the thermal closing reaction, CPD to DHP, and half-lives at 20 °C were found to range from 11 days (X = CHO) to 36 years (X = CN), with alkenyl functions being from 56 days to 10 years. The visible light opening reaction, DHP to CPD, showed relative rates of 1 (X = CN) to 240 (X = CH=CMe₂).

Full text of DOI:10.1021/jo4024446

Article
pubs.acs.org/joc
Syntheses of Dihydropyrene−Cyclophanediene Negative
Photochromes Containing Internal Alkenyl and Alkynyl Groups and
Comparison of Their Photochemical and Thermochemical Properties
Khurshid Ayub‡ and Reginald H. Mitchell*
Department of Chemistry, University of Victoria, P.O. Box 3065, Victoria, BC, Canada V8W 3V6
S
* Supporting Information
ABSTRACT: Synthesis of a variety of 8,16-disubstituted-anti-[2.2]-
metacyclophanedienes (CPD) with alkenyl and alkynyl internal (8,16) groups
is described together with their analogous dihydropyrenes (DHP). Eyring and
Arrhenius parameters were determined for the thermal closing reaction, CPD to
DHP, and half-lives at 20 °C were found to range from 11 days (X = CHO) to
36 years (X = CN), with alkenyl functions being from 56 days to 10 years. The
visible light opening reaction, DHP to CPD, showed relative rates of 1 (X = CN)
to 240 (X = CHCMe2).
functionality at the 2 and/or 7 positions of the DHP as in 3, it
is at the cost of thermal stability of the CPD 4.5
INTRODUCTION
■
Negative photochromes (−) are not as well-known as their
positive (+) counterparts1 but are interesting because the
thermally stable isomer is the more colored one (positive ones
have the colorless form, the more stable). The colored form
bleaches on exposure to visible (longer wavelength) light and
returns to the colored isomer on exposure to UV (shorter
wavelength) light or in some cases thermally (T). Dihydropyr-
enes (DHPs), such as 1, are thus negative-thermal [(−)T] photo-
chromes because the deep red-purple 1 opens completely to
the colorless cyclophanediene (CPD) form 2 when irradiated
with visible light (λ > 400 nm). The latter completely reverts to
DHP 1 on irradiation with UV light (λ < 350 nm) and also slowly
thermally (t1/2 = 7.3 days at 20 °C, 5.75 h at 46 °C) (Scheme 1).2
Since DFT calculations on the transition state of the CPD to
DHP interconversion suggested radical character with spin
density at the internal 8,16 positions,6 we concentrated on
influencing this by first changing the internal group. These
calculations suggested that the cyano cyclophanediene 5 should
have a high activation barrier for thermal cyclization to the
dihydropyrene 6. Indeed, it did, with an estimated half-life at
room temperature of about 30 years!3 However, a new problem
arose in that the corresponding dihydropyrene 6 suffered from
an unexpectedly easy (half-life at 50 °C = 8.3 h) sigmatropic shift
of the cyano groups over the π skeleton of the dihydropyrene to
form 7, then 8, and finally 9 by elimination of HCN.
Scheme 1
Again we were guided by calculations and subsequently were
able to report4 that isobutenyl groups at the internal position
not only slow down the thermal return of cyclophanediene 10
to dihydropyrene 11 but also resist the sigmatropic shift of the
internal groups over the π system of the dihydropyrene, which
result in destruction of the photochrome. In addition, it turned out
that the quantum yield of the opening reaction (11 to 10)[Φ = 0.12]
was three times higher than that of 1 [Φ = 0.039].4 In that paper,4
we reported calculations for a variety of internal groups.
Application of photoswitches for use in memory devices requires
consideration of their thermal stability, fatigue resistance, overlap of
the absorption spectra of the open and closed forms, quantum yield
of the interconversions, and ability to nondestructively read the
open and closed forms. Our more recent research focus has
concentrated on two of these, namely design of more thermally
stable dihydropyrene-based photoswitches with high quantum
yields of interconversion, particularly for the photoopening
reaction of dihydropyrenes with visible light.3,4 Although the
latter objective is easily addressed by incorporating carbonyl
Received: November 2, 2013
Published: December 23, 2013
© 2013 American Chemical Society
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We now have been able to synthesize several of these, and so
this paper reports the synthesis of these molecules and our
experimental findings on the photochemical and thermal
interconversion reactions.
aldehyde groups of 26 was carried out early in the sequence
because of the fragility of the dialdehyde 28. Like DHP 6, DHP
28 easily cascaded through a sequence to 31, presumably via 29
and 30.
Thus, Wittig reaction of mixed −SMe isomers of bis-aldehyde
264 with a preformed ylide derived from methyltriphenylphos-
phonium bromide and BuLi for 1 h at 20 °C yielded 93% of the
desired bis-vinyl derivative 32 (Scheme 2) as a mixture of
isomers. For characterization, a single isomer of 32, in which
both −SMe groups are pseudoequatorial, was isolated, mp
228−229 °C. Full characterization for all new compounds is
given in the Experimental Section. For synthetic purposes, the
mixed isomers of 32 with dimethoxycarbonium tetrafluoro-
borate10 gave 79% of the bis-sulfonium salts 33, which on
Hoffmann elimination gave the colorless cyclophanediene 12 in
1
90% yield. In the H NMR spectrum of 12, the protons of the
internal vinyl substituent appeared clearly as three doublets of
doublets at δ 6.32, 5.47, and 4.84.
Quantitative isomerization of 12 to 13 could easily be
obtained either thermally or by irradiation with UV light;
however for larger sized samples, it was most easily
accomplished thermally. Heating a solution of 12 at 100 °C
in toluene under argon for about 1 h was determined to be the
optimum time and was easily monitored by following the
1
changes in the H NMR spectrum. In 13, the DHP external
protons appearing at δ 8.79 (s), 8.65 (d), and 8.08 (t) are
significantly deshielded from the analogous ones of 12 by 2.41,
2.05, and 1.01 ppm, respectively. The internal vinyl protons at δ
2.67, 2.06, and 0.50 (all as doublets of doublets) are highly
shielded by 2.17, 3.41, and 5.82 ppm, respectively, caused by
the strong DHP ring current from those quoted above for 12.
RESULTS AND DISCUSSION
■
Synthesis. Our first targets were the vinyl- (12), propenyl-
(14, 16, 18) and styryl-substituted (20, 22, 24) CPDs and their
corresponding DHPs. The route used4 was similar to that for
the isobutenyl derivative 10, in which conversion of the
Scheme 2
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1H NMR peaks for the dihydropyrene skeleton were found in
the region of δ 8−9, while the internal olefinic (δ 3.21 and 0.09)
and methyl protons (δ 0.33(15) and 0.32 and 0.17 (17)) were
quite shielded, being in the center of the ring current.
The styryl-substituted CPDs were obtained analogously (see
Scheme 4) as a mixture of 20 (ZZ, 44%) 22 (EZ, 38%), and 24
(EE, 18%) that were easily separated by column chromato-
graphy. The styryl olefinic and aromatic protons were quite
distinct for the (Z)- and (E)-isomers. The olefinic protons
of the (Z)-styryl group in 20 appeared at δ 5.96 and 5.80
whereas in the (E)-styryl fragment in 24 these protons
appeared accidentally as a singlet at δ 6.86.
Wittig reaction of the bis-aldehyde 26 with the ylide derived
from ethyltriphenylphosphosphonium bromide and BuLi, at
20 °C for 1 h, gave a good yield of 34 as a complex mixture
of cyclophane−SMe and double bond (ZZ)-, (ZE)-, and
(EE)-isomers (Scheme 3), and so the mixture was directly
Scheme 3
Thermal isomerization of the (ZZ)-styryl CPD 20 (as
described above) gave (ZZ)-styryl DHP 21 as orange crystals
from cyclohexane, mp 152−154 °C. The olefinic protons in 21
appeared shielded at δ 0.28 and 4.21 as doublets (J = 12.6 Hz).
The ortho protons of the styryl aromatic rings are also shielded
to a small extent by the DHP ring current. The (EE)-styryl
DHP 25 was obtained as dark green crystals, mp 232−234 °C.
A significant difference in λmax is observed between 21 and 25.
The absorption wavelength in the visible region for 25 is
observed at 466 and 597 nm whereas the corresponding bands
for 21 are observed at 487 and 624 nm. The olefinic protons in
25 appeared at δ 0.87 and 3.21.
To explore the electronic effect of substituents on the
thermal behavior of cyclophanedienes, functionalized styryl
substituents were also introduced. We synthesized the −OCH3,
−NO2, and −CH3 substituted styryl CPDs 43−51 as repre-
sentative examples of electron -donor, -acceptor, and -neutral
(hyperconjugation) substituents. A general synthesis of these
cyclophanedienes and then conversion into dihydropyrenes is
shown in Scheme 4; however, details of the syntheses, yields,
converted by Hoffmann elimination as for 12 to a 6:1 mixture
of 14 (ZZ) and 16 (ZE). Existence of the third isomer 18 (EE)
in this mixture was not confirmed.
The (ZZ)- or cis−cis-isomer 14 was expected (nonstabilized
1
ylide) to predominate, and did, and in its H NMR spectrum,
the cis orientation of the double bond was established by a
coupling constant of 12.0 Hz between the olefinic protons and
by an IR band at 711 cm−1. All protons and carbons in the
major isomer 14 could easily be accounted for but in the minor
isomer 16, the cis-propenyl protons and carbons were obscured
by overlap with peaks from the major isomer. The trans-
propenyl internal group in 16 was characterized by a coupling
constant of 15.4 Hz for the alkene proton at δ 5.94 and by an
IR band at 962 cm −1. DHPs 15 and 17 were obtained pre-
paratively by thermal isomerization of 14 and 16, as above, or
by irradiation with UV light (λmax < 300 nm). The characteristic
Scheme 4
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ratios of isomers, and characterizations are given in the
Experimental Section.
half-lives (t1/2) at two or three temperatures to be more useful.
While the full Eyring and Arrhenius data are given in the
Supporting Information, Table 1 gives the half-life data
determined for the compounds in this study.
As examples with extended linear conjugation, cyclophane-
diene 61 represents a simple example; however, all attempts to
synthesize this compound resulted in a nonseparable mixture of
isomers. On the other hand, the methyl-substituted analogues
62−64 could be easily synthesized as a mixture of (ZZ):(ZE):
(EE) isomers which could be separated by column chromatog-
raphy. Syntheses of compounds 62−67 were analogous to
those of 20−25 above and are described in detail in the
Experimental Section.
The observed half-life values follow surprisingly well the
calculated activation barriers:4 for example, both ΔH⧧ and τ1/2
(20 °C) follow the order 10 > 14 > 20. The (ZZ)-internal
alkenes thermally convert more slowly than the (ZE)-isomers,
which are slower than the (EE)-isomers, e.g., for τ1/2 (20 °C)
20 > 22 > 24. Para-substituents on the phenyl ring of 20 seem
to have a larger effect on the (ZZ)-isomer than on the others.
The mixed internal group compound 77 appears to have a
barrier approximately midway between 5 and 89. It is worth
noting that our initial choice for target,4 the bis-isobutenyl
compound 10, was a good one, as all of the compounds that
follow have faster thermal conversions, though all are much
slower and thus are better than the parents 89 or 90 .
In order to investigate an acetylene-substituted CPD, the
Wittig reaction of bis-aldehyde cyclophane 22 with the ylide
derived from bromomethyltriphenylphosphonium bromide
and KOtBu at 20 °C for 1 h with subsequent in situ elimina-
tion of HBr yielded the bis-acetylene cyclophane 68 as a mix-
ture of isomers which was directly subjected to a sequence of
S-methylation with (CH3O)2CHBF4 and Hoffmann elimination
as previously described to give the bis-acetylene CPD 69 as
colorless solid. The alkyne was characterized by an IR C−H
stretch at 3293 cm−1. Bis-acetylene DHP 70 was obtained by
irradiation of cyclophanediene 69 with UV light as dark green
crystals, with the internal alkyne protons appearing at δ −0.09,
and the IR C−H stretch at 3274 cm−1. Note that neither 69
or 70 showed a clear CC stretch.
Photo-opening Ractions. Visible light induced relative
opening rate studies were performed using a 500 W tungsten
lamp with an orange plastic ∼490 nm cutoff filter (see the
1
Supporting Information for spectrum) using H NMR studies
in toluene-d8, side by side with the standard, as we have
described previously.5c Because the compounds tested in this
study are slower opening than benzo-DHP 1, first the styryl
compound 52 was measured against 1 and then 52 was used to
calibrate the others that are given in Table 2. Our initial target,
the isobutenyl DHP 11, still proved to open fastest, at about
25% of the rate of 1, but the (ZZ)-isomers of the styryl, p-Me,
and p-OMe styryl compounds (21, 52, and 55) all showed very
similar and acceptable rates and all opened completely. Some of
the compounds (indicated in Table 2 by the *) formed
photostationary states. Surprisingly, the (EE)-styryl compounds
25, 54, 57, and 60, the (EE)-butadienyl compound 67, and the
phenylethynyl compound 85 did not result in any measurable
open (CPD) form under these conditions, though it is possible
that the CPD tail extended far enough into the visible to permit
any “open” form to close again (the quantum yield of the
photoclosing reaction is close to 1, much higher than that of the
photoopening reaction9). Certainly when the trans−trans-styryl
CPD 24 was irradiated under the same conditions, it closed to
the DHP 25. However, use of a 590 nm red plastic filter also
failed to open it. The (ZZ)- and (ZE)-butadienyl compounds
65 and 66 only isomerized to the (EE)-isomer 67. The vinyl
compound 13 did not open appreciably, but decomposed.
Robb8 has shown that the photoopening reaction of the parent
91 occurs through a conical intersection between a biradical
excited state and the ground one. However, the former is not
the lowest energy excited state, and moreover excitation to it is
symmetry forbidden. Stabilization of this state relative to the
highly populated zwitterionic excited state should accelerate the
photoopening reaction. However, it is not obvious whether this
would be a dominating factor or not and how substituents
affect this. Compound 15 with cis-propenyl groups completely
For comparison purposes, the unsymmetrical cyclophane-
dienes 77 and 84 were also synthesized, starting from 7111 or
79 with 72,12 as shown in Scheme 5, with details in the
Experimental Section. Dibromide 79 required for the synthesis
of 84 was synthesized in the three-step process13 shown in
Scheme 6 from commercially available 2,6-dimethylaniline 86.
Thermochemical Results. The objective of our work was
to produce cyclophanedienes which have relatively slow
thermal return reactions to the corresponding dihydropyrenes.
Following the thermal return reaction is relatively straightfor-
ward using either UV/vis spectroscopy5b or by 1H NMR
spectrometry3,5c since the CPDs show very different spectra
from the DHPs. Then use of Arrhenius plots leads to Eact and ln
A data, while Eyring plots yield ΔH⧧ and ΔS⧧ data. However,
understanding the thermal cyclization of CPDs to DHPs just by
looking at the thermochemical data proves to be more difficult
than one might imagine;7 for example, direct comparison of
energies of activation (Eact) tends to be somewhat misleading
for this reaction because there appears to be a large variation in
the pre-exponential factor (ln A) from system to system.3
We have thus found that comparison of thermal conversion
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Scheme 5
Scheme 6
Table 1. Thermal Half-Lives for the CPD to DHP Conversion Determined at Three Different Temperatures
a
a
a
compd
5 (ref 4)
internal group(s)
τ1/2 (20 °C)
τ1/2 (50 °C)
τ1/2 (100 °C)
ΔG‡(calc) refs 4 and 6
−CN
∼36 y
16 y
110 d
65 d
33 d
49 d
28 d
25 d
23 d
20 d
18 d
16 d
14 d
14 d
11 d
11 d
9.8 d
10 d
9.2 d
8.5 d
6.3 d
24 h
15 h
5.0 h
4.5 h
94 m
2.1 h
2.2 h
2.2 h
1.9 h
91 m
82 m
92 m
73 m
87 m
64 m
77 m
59 m
63 m
55 m
45 m
40 m
7.7 m
25.2
27.5
26.6
24.3
26.5
10 (ref 4)
−CHCMe2
14
(ZZ) −CHCHMe
−CCH
10 y
69
8.0 y
6.0 y
5.0 y
4.5 y
4.3 y
4.0 y
3.1 y
2.8 y
2.5 y
2.0 y
1.9 y
1.8 y
1.7 y
1.7 y
1.6 y
1.2 y
56 d
30 d
46
(ZZ) −CHCHPh-OMe-p
(ZZ) −CHCHPh-Me-p
(ZZ) −CHCH-CHCMe2
(ZZ) −CHCHPh
(ZE) −CHCH-CHCMe2
(ZE) −CHCPh-OMe-pH
(ZE) −CHCHPh
(ZE) −CHCHPh-Me-p
(EE) −CHCHPh-OMe-p
(ZZ) −CHCHPh-NO2-p
(ZE) −CHCHPh-NO2-p
(EE) −CHCHPh-Me-p
(EE) −CHCHPh-NO2-p
(EE) −CHCH-CHCMe2
(EE) −CHCHPh
−CHCH2
43
62
20
27.0
24.7
26.5
63
47
22
44
48
49
50
45
51
64
24
23.6
23.2
12
84
−Me; −CCPh
77 (PhH)(CDCl3)
27
−Me; −CN
12 d; 9.5 d
11 d
6.7 h 5.2 h
4.2 h
69 m
2.0 h
22.3
21.6
20.4
20.6
−CHO
89 (ref 3)
90 (ref 3)
−Me
42 h
54 h
−Me (5,13-di-t-Bu)
a
h = hours; d = days; m = minutes. Errors estimated are <5%.
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Table 2. Visible Light Opening Rates for the Dihydropyrenes
to the Cyclophanedienes, Measured Relative to that of 1 =
1000 with Calculated Rates Relative to Parent 91
b
c
calcd relative relative rates vs
rates vs DHP
91 = 1000
benzo DHP
1 = 1000
d
compd (int group)
CPD:DHP
a
6
−CN
∼6
65
∼1
4
60:40
60:40
a
70 −CCH
15 (ZZ) −CHCHMe
180
200
11
12
a
58 (ZE) −CHCHPh-
20:80
NO2-p
a
23 (ZE) −CHCHPh
740
980
45
60
80:20
50:50
a
53 (ZE) −CHCHPh-
Me-p
a
56 (ZE) −CHCHPh-
1130
69
60:40
OMe-p
21 (ZZ) −CHCHPh
2500
2900
150
180
Figure 2. Comparison of the UV−vis spectra tails for the para-
substituted cis,cis-styryl CPDs 20, 43, 46, and 49.
55 (ZZ) −CHCHPh-
OMe-p
52 (ZZ) −CHCHPh-
Me-p
2900
180
240
is consistent with the p-nitro DHP 58 showing the slowest rate
of opening with considerable CPD content of the photosta-
tionary state, while the p-Me DHPs 52 shows the fastest rate
and complete conversion.
11 −CHCMe2
3900
a
b
c
P = photostationary state. Approximately 16.25× rate for 1.5c Error
d
1
estimates are less than 5%. Estimated by H NMR.
Sigmatropic Rearrangement. The remaining objective
that we have not yet discussed is the sigmatropic rearrangement
that occurs >50 °C for the dicyano DHP 6 which ultimately led
to 9.3 Happily, for the bis-isobutenyl DHP 11, the rearrange-
ment is suppressed and is not observed at all at 100 °C. With
the exception of the diformyl DHP 28 which isomerized to 29
(Eact estimated to be <20 kcal/mol) and then on to 31 even
more easily than for 6, the other DHPs prepared in this study
all showed no evidence of rearrangement at 100 °C.
opened, while 17, with one trans-group did not open at all! For
the styryl compounds, the (ZE)-compounds do open, though
more slowly than the (ZZ)-isomers. A qualitative explanation
can be made on examination of the UV−vis spectra of the
styryl-CPDs shown in Figure 1 (equimolar concentrations).
CONCLUSIONS
■
In this paper, the synthesis of a number of cyclophanedienes
with a variety of different internal alkenyl and alkynyl groups
and their corresponding dihydropyrenes is described. The
thermal conversions of the CPDs to DHPs and the photo-
chemical conversions of the DHPs to CPDs are measured and
compared. CPDs with cis-alkenyl internal groups showed the
slowest thermal conversion to DHPs, with half-lives of several
years at 20 °C, which is much better than that observed
for benzo CPD 2, but not as good as for isobutenyl CPD 10.
The photoopening reaction rate for the corresponding cis-
alkenyl DHPs was similar to that of DHP 11. As well, for the
compounds studied, the sigmatropic rearrangement was
suppressed. Of the compounds studied here, the CPD/DHP
pairs 20/21, 43/52, and 46/55 show the most promising
properties as photochromic switches. The relative observed
thermal closing rates, CPD to DHP, agree reasonably well with
previous4 calculations.
Figure 1. Comparison of the UV−vis spectra tails for the styryl CPDs
20, 22, and 24.
For cis,cis-20 (blue, Figure 1), the tail has reached baseline
before 510 nm. For cis,trans-22 and trans,trans-24 the tails show
increasingly significant tails above 500 nm, providing a qualita-
tive explanation for DHP, cis,cis-21 having the fastest opening
rate, while for the trans compounds the photoclosing reaction
increasingly competes.
EXPERIMENTAL SECTION
The general conditions and the numbering system used for NMR
assignments are given in the Supporting Information.
■
For the para-substituted cis,cis-styryl CPDs shown in Figure 2
(equimolar concentrations), again examination of the CPD tails
General Thermolysis Procedure Used for Converting CPDs
into DHPs. The cyclophanediene (25 mg) in toluene-d8 (2 mL) was
sealed in an NMR tube under argon, which was then heated at 100 °C
until 1H NMR indicated conversion to the dihydropyrene was
complete (∼1−2 h). Evaporation yielded the DHP as colored crystals.
2,10-Bis(methylthio)-8,16-diethenyl-anti-[2.2]metacyclophane
(32). BuLi (5.3 mL, 2.5 M in hexanes, 13 mmol) was added dropwise
to a stirred suspension of methyltriphenylphosphonium bromide
(3.6 g, 10.1 mmol) under argon in THF (40 mL) at 0 °C. After 20 min,
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diformylmethylthiocyclophane 264 (1.5 g, 4.21 mmol) was added to
this clear orange-red solution, and stirring was continued at 20 °C for
1.5 h. Water was then added followed by dichloromethane. The
organic extract was washed, dried, and evaporated. The crude product
was chromatographed over silica gel using hexanes/dichloromethane
(7:3) as eluent and gave 1.38 g (93%) of divinylmethylthiocyclophane
32 as a mixture of isomers: EIMS m/z 352 (M+); 1H NMR δ 7.98 (d,
J = 7.6 Hz), 7.80 (d, J = 7.7 Hz), 7.67−7.62 (m), 7.53−7.51 (m),
7.45−7.42 (m), 7.20−7.16 (m), 7.08−7.05 (m), 6.94 (t, J = 7.4 Hz),
4.80−4.60 (m), 4.52−4.40 (m), 4.28−4.25 (m), 4.11−4.08 (m), 3.08−
3.04 (m), 2.87 (t, J = 12.0 Hz), 2.66 (t, J = 12.1 Hz), 2.12, 2.08 (s).
For synthetic purposes, these were used directly in the next step. For
characterization purposes, a single isomer of 32, in which the 1,9-
methylthio groups are pseudoequatorial was obtained by rechroma-
(C-12,14), 36.1 (C-10b,10c); IR ν (KBr) 3032, 3007, 1621, 1399,
1295, 912, 841 cm−1; UV−vis (cyclohexane) λmax nm (εmax) 339
(71300), 377 (30000), 462 (5600), 608 (100); EIMS m/z 256 (M+);
HRMS calcd for C20H16 256.1252, found 256.1251. Anal. Calcd: C,
93.70; H, 6.30. Found: C, 93.92; H, 6.57.
(b) UV Irradiation (Only Used for Small Samples To Indicate That
the Reaction Proceeds) . The cylophanediene 12 (2 mg) was
dissolved in sufficient cyclohexane or dichloromethane to fill a quartz
UV cuvette, which was then irradiated with 254 nm light from a hand-
held TLC lamp. The irradiation was monitored at 15 s intervals until
complete conversion to dihydropyrene 13 was observed (the bands at
462 and 608 nm maximize). This required 45−75 s. The UV−vis
spectrum observed was the same as that obtained for thermolysis,
method a.
1
8,16-Bis(prop-1-enyl)-anti-[2.2]metacyclophane-1,9-dienes (14)
and (16). Using the same procedure as for the sequence 26−32−
33−12 above, except that ethyltriphenylphosphonium bromide was
used, followed by the same methylation/Hoffmann elimination
sequence, yielded after chromatography 202 mg (90%) of the two iso-
mers 14 and 16 in approximately a ratio of 6:1. By further chromato-
graphy, these could be partially separated. One fraction was enriched
tography as colorless crystals: mp 228−229 °C; H NMR δ 7.81 (dd,
J = 7.6, 1.1 Hz, 2H, H-6,14), 7.18 (dd, J = 7.5, 1.0 Hz, 2H, H-4,12),
7.07 (t, J = 7.5 Hz, 2H, H-5,13), 4.80−4.75 and 4.48−4.42 (m, 6H,
H-19,20,17,18), 4.27 (dd, J = 11.6, 4.2 Hz, 2H, H-1,9), 3.06 (dd, J = 12.6,
4.2 Hz, 2H, H-2eq,10eq), 2.66 (dd, J = 12.1, 11.9 Hz, 2H, H-2ax,10ax),
2.13 (s, 3H, SMe); 13C NMR δ 147.0 (C-8,16), 135.7 (C-7,15), 135.2
(C-3,11), 135.0 (C-17, 19), 128.9(C-4,12), 126.6 (C-5,13), 125.4
(C-6,14), 120.6(C-18,20), 53.2 (C-1,9), 43.3 (C-2,10), 15.3 (C-
21,22); IR ν (KBr) 3078, 2960, 2909, 1438, 1397, 994, 930, 771, 748
cm−1; UV−vis (cyclohexane) λmax nm (εmax) 227 (17300), 288 (3986);
EIMS m/z 352 (M+); HRMS calcd for C22H24S2 352.1319, found
352.1319. Anal. Calcd: C, 74.95; H, 6.86. Found: C, 74.48; H, 6.91.
1,10-Bis(methylthio)-8,16-divinyl-anti-[2.2]metacyclophane Bis-
sulfonium Salt (33). The mixed isomers of 32 (360 mg, 1 mmol)
in dry CH2Cl2 (20 mL) were added slowly to (MeO)2CHBF4 (Borch
reagent)10 (80% oil, 580 mg, 2.86 mmol) in CH2Cl2 (14 mL) at
−78 °C with stirring under nitrogen. The mixture was then stirred at
20 °C for 3 h. The CH2Cl2 was then decanted from the oil, ethyl
acetate (40 mL) was added, and stirring was continued for another 3 h
(this was repeated if a nonsticky white powder was not obtained). The
white precipitate was collected and dried to give 440 mg (79%) of the
1
in the major isomer, (ZZ)-14: H NMR δ 6.94 (t, J = 7.4 Hz, 2H,
H-5,13), 6.46 (d, J = 7.4 Hz, 4H, H-4,6,12,14), 6.12 (qd, J = 12.0, 1.8 Hz,
2H, H-17,19), 6.09 (s, 4H, H-1,2,9,10), 5.23 (qd, J = 12.0, 7.2 Hz, 2H,
H-18,20), 1.55 (dd, J = 7.3, 1.8 Hz, 6H, H-21,22); 13C NMR δ 142.3
(C-8,16), 136.9 (C-3,7,11,15), 132.0 (C-1,2,9,10), 129.4 (C-17,19),
128.2 (C-5,13), 126.0 (C-18,20), 125.5 (C-4,6,12,14), 15.4 (C-21,22);
IR ν (thin film) 3036, 3001, 2930, 2848, 1599, 1561, 1434, 962, 929,
858, 842, 771, 711, 665 cm−1; UV−vis (cyclohexane) λmax nm (εmax
)
215 (25000), 243 (26200), 277 (11500), 340 (∼ 2500); EIMS m/z
284 (M+); HRMS calcd for C22H20 284.1565, found 284.1562.
The second fraction was enriched in the minor isomer, (ZE)-16: 1H
NMR δ 6.98 (t, J = 7.4 Hz, 1H, H-13), 6.86 (t, J = 7.4 Hz, 1H, H-5),
6.44 (d, J = 7.4 Hz, 2H, H-12,14), 6.42 (d, J = 7.4 Hz, 2H, H-4,6),
6.10−6.14 (AB*, 4H, H-1,2,9,10), 5.94 (dq, J = 15.4, 6.7 Hz, H-20),
1.57 (dd, J = 1.9 Hz, J = 6.6 Hz, 3H, H-21), 1.52 (dd, J = 6.6, 1.6 Hz,
3H, H-22) H-17−19*; 13C NMR δ 145.9 (C-8), 141.3 (C-16), 137.4
(C-11,15), 135.1 (C-3,7), 132.6 (C-2,9), 131.8 (C-17), 130.8 (C-19),
129.8 (C-20), 128.5 (C-13), 127.8 (C-5), 126.2 (C-4,6), 125.4 (C-12,14),
18.2 (C-22), 15.3 (C-21), C-1,10,18*. *Indicates when peaks are not
distinct (overlapped by the major isomer).
1
sulfonium salt 33: H NMR (DMSO-d6) δ 7.72 (d, J = 7.8 Hz), 7.58
(d, J = 7.4 Hz), 7.54 (d, J = 7.3 Hz), 7.41 (d, J = 7.6 Hz), 7.28 (t, J =
7.6 Hz), 7.13 (t, J = 7.4 Hz), 5.2−4.6 (m), 3.46−3.05 (m), 2.90,
2.87(s). This was used directly in the next step.
8,16-Divinyl-anti-[2.2]metacyclophane-1,9-diene (12). t-BuOK
(250 mg, 2.23 mmol) was added to a stirred suspension of the bis-
sulfonium salt 33 (440 mg, 0.791 mmol) in THF (20 mL) under
argon at 20 °C in a vessel wrapped in aluminum foil to exclude light.
After the mixture was stirred for 30 min, water and CH2Cl2 were
added. The organic extract was washed, dried, and evaporated (all with
protection from light). The product was chromatographed over silica
gel using hexanes as eluent gave 182 mg (90%) of 12 as colorless
crystals from cyclohexane: 1H NMR δ 7.07 (t, J = 7.4 Hz, 2H, H-5,13),
6.60 (d, J = 7.4 Hz, 4H, H-4,6,12,14), 6.38 (s, 4H, H-1,2,9,10), 6.32
(dd, J = 17.4, 11.0 Hz, 2H, H-17,19) 5.47 (dd, J = 17.4, 1.8 Hz, 2H, H-
18,20b), 4.84 (dd, J = 11.0, 1.8 Hz, 2H, H-18,20a); 13C NMR δ 146.4
(C-8,16), 135.8 (3,7,11,15), 135.2 (C-17,19), 133.2 (C-1,2,9,10),
129.5 (C-5,13), 126.7 (C-4,6,12,14), 118.9 (C-18,20); IR ν (KBr)
3077, 3049, 3004, 1618, 1436, 1397, 993, 903, 861, 807, 764, 605
cm−1; UV−vis (cyclohexane) λmax nm (εmax) 202 (51700), 242
(33170), 279 (12370), 339 (11000), 377 (5710), 390 sh (2100);
EIMS m/z 256 (M+); HRMS calcd for C20H16 256.1252, found
256.1255. Anal Calcd: C, 93.70; H, 6.30. Found: C, 93.51; H, 6.41.
Attempted mp determination isomerized 12 into DHP 13.
10b,10c-Bis(prop-1-enyl)-trans-10b,10c-dihydropyrenes (15) and
(17). Using the same thermolysis procedure used for 12 above, CPD
15 (25 mg) was converted to (ZZ)-DHP 15 (25 mg, 100%): 1H NMR
δ 8.64 (d, J = 7.6 Hz, 4H, H-1,3,6,8), 8.63 (s, 4H, H-4,5,9,10), 8.05 (t,
J = 7.6 Hz, 2H, H-2,7), 3.21 (qd, J = 12.4, 7.3 Hz, 2H, H-12, 14), 0.33
(dd, J = 7.3, 1.8 Hz, 6H, H-15,16), 0.09 (qd, J = 12.4, 1.8 Hz, 2H, H-
11,13); 13C NMR δ 135.3 (C-3a,5a,10a,10d), 126.1 (C-4,5,9,10),
125.4 (C-1,3,6,8), 123.61 (C-12,14), 123.59 (C-2,7), 121.9 (C-11,13),
11.5 (C-15,16); EIMS m/z 284 (M+); HRMS calcd for C22H20
284.1565, found 284.1557.
Thermolysis of the mostly (ZE)-isomer 16 gave 100% of (ZE)-
1
DHP 17: H NMR δ 8.71 (d, J = 7.7 Hz, 2H, H-4,10), 8.67 (d, J =
7.6 Hz, 2H, H-6,8), 8.66 (d, J = 7.6 Hz, 2H, H-5,9), 8.58 (d, J = 7.7
Hz, 2H, H-1,3), 8.07 (t, J = 7.8 Hz, 1H, H-7), 8.02 (t, J = 7.7 Hz, 1H,
H-2), 3.14 (qd, J = 12.4, 7.3 Hz, 1H, H-14), 2.36 (qd, J = 15.1, 6.5 Hz,
1H, H-12), 0.32 (dd, J = 7.2, 1.8 Hz, 3H, H-15), 0.17 (dd, J = 6.7, 1.5 Hz,
3H, H-16), 0.15 (m, 2H, H-11,13); 13C NMR δ 135.2 (C-5a,10d),
134.8 (C-10a,3a), 126.1 (C-5,9), 125.2 (C-4,10), 125.1 (C-6,8), 124.2
(C-1,3), 123.44 (C-2), 123.39 (C-7), 123.0 (C-13), 122.8 (C-14),
120.6 (C-11), 120.3 (C-12), 16.4 (C-15), 11.1 (C-16); IR ν (KBr)
3018, 2923, 2852, 1365, 836, 797, 692 cm−1; UV−vis (cyclohexane)
λmax nm (εmax) 346 nm (46600), 369 (12700), 390 (21100), 482
(4500), 626 (120). Anal. Calcd: C, 92.91; H, 7.09. Found: C, 92.91; H,
7.10.
8,16-Bis(2-phenylethenyl)-1,9-bis(methylthio)-anti-[2.2]-
metacyclophane (35). Using the same procedure as for 22 to 32
above, diformylmethylthiocyclophane 22 (1.40 g, 3.93 mmol) with the
ylide prepared by reaction of t-BuOK (4.0 g, 36 mmol) and benzyl
triphenylphosphonium bromide (5.0 g, 11.5 mmol) in THF (30 mL)
10b,10c-Divinyl-trans-10b,10c-dihydropyrene (13). (a) Thermol-
ysis (Best for Preparative Samples). Cyclophanediene 12 (25 mg) in
toluene-d8 (2 mL) was sealed in an NMR tube under argon, which was
then heated at 100 °C until 1H NMR indicated conversion to
dihydropyrene 13 was complete (∼1−2 h). Evaporation yielded 25 mg
(100%) of 13 as dark green crystals from cyclohexane: mp 163−165
1
°C; H NMR δ 8.79 (s, 4H, H-4,5,9,10), 8.65 (d, J = 7.6 Hz, 4H, H-
1,3,6,8), 8.08 (t, J = 7.6 Hz, 2H, H-2,7), 2.67 (dd, J = 10.3, 1.4 Hz, 2H,
H-12,14b), 2.06 (dd, J = 17.0, 1.5 Hz, 2H, H-12,14a), 0.50 (dd, J =
17.0, 10.3 Hz, 2H, H-11,13); 13C NMR δ 133.8 (3a,5a,10a,10d), 128.6
(C-11,13), 125.5 (C-4,5,9,10), 124.4 (C-1,3,6,8), 123.8 (C-2,7), 109.8
670
dx.doi.org/10.1021/jo4024446 | J. Org. Chem. 2014, 79, 664−678

The Journal of Organic Chemistry
Article
followed by column chromatography using hexanes/dichloromethane
(7:3) gave 400 mg (20%) of mixed isomers of distyrylmethylth-
iocyclophane 35: 1H NMR δ 7.98 (d, J = 7.7 Hz), 7.96 (d, J = 8.0 Hz),
7.91 (d, J = 7.6 Hz), 7.84 (d, J = 7.6 Hz), 7.38−6.90 (m), 6.34−6.27
(m), 5.93 (d, J = 12.4 Hz), 5.88 (d, J = 12.4 Hz), 5.73 (d, J = 16.4 Hz),
5.22 (d, J = 16.4 Hz), 5.16 (d, J = 16.4 Hz) 4.42−4.00 (m), 3.16−2.95
(m), 2.73−2.53 (m), 2.19, 2.18 (s), 1.61, 1.38, 1.37 (3 singlets); EIMS
m/z 504 (M+); HRMS calcd for C34H32S2 504.1945, found 504.1938.
These were used directly in the next step.
H-21−24), 6.03−6.01 (m, 4H, H-17−20), 4.21 (d, J = 12.6 Hz, 2H,
13,14), 0.28 (d, J = 12.6 Hz, 2H, H-11,12); 13C NMR (CD2Cl2) δ
136.8 (C-15,16), 134.2 (C-3a,5a,10a,10d), 128.8 (C-17−20), 127.5
(C-13,14), 126.9 (C-4,5,9,10), 126.4 (C-21−26), 125.7 (C-1,3,6,8),
124.1 (C-2,7), 122.5 (C-11,12), 36.7 (C-10b,10c); IR ν (KBr) 3024,
844, 830, 694, 609 cm−1; UV−vis (cyclohexane) λmax nm (εmax) 351
nm (56400), 369 (15300), 395 (25700), 487 (5100), 624 (95); EIMS
m/z 408 (M+); HRMS calcd for C32H24 408.1878, found 408.1887.
Anal. Calcd: C, 94.08; H, 5.92. Found: C, 93.90; H, 6.02.
8,16-Bis(2-phenylethenyl)-1,9-bis(methylthio)-anti-[2.2]-
metacyclophane Bis-sulfonium Salt (39). Using the same procedure
as for 33 above, from the mixed isomers of 35 (600 mg, 1.19 mmol)
with Borch reagent (80% oil, 1g, 5 mmol) in CH2Cl2 (10 mL) gave
700 mg (83%) of bis-sulfonium salt 39: 1H NMR (DMSO-d6) δ 7.75−
7.18 (m), 7.08−6.96 (m), 6.37−5.91 (m), 5.33 (d, J = 16.4 Hz), 4.61−
4.51 (m), 4.28−3.95 (m), 3.48−3.37 (m), 3.29−3.15 (singlets) 2.98−
2.80 (singlets), 2.27, 2.29 (s), 2.14, 1.96 (s), which were used directly
in the next step.
8,16-Bis(2-phenylethenyl)-anti-[2.2]metacyclophane-1,9-dienes
(20), (22), and (24). Using the same procedure as for 12 above, the
bis-sulfonium salt 39 (650 mg, 0.93 mmol) and t-BuOK (500 mg, 4.5
mmol) in THF (10 mL) gave a mixture of cyclophanedienes which
was purified by column chromatography using hexanes-dichloro-
methane 85: 15 as eluent. Elued first was the cis−cis or bis-(1Z)-
isomer 20, 152 mg (41%), as pale yellow crystals from cyclohexane.
1H NMR (CD2Cl2) δ 7.18 (t, J = 7.4 Hz, 2H, H-5,13), 7.09−7.02 (m,
10b-((1E)-2-Phenylvinyl)-10c-((1Z)-2-phenylvinyl)-trans-10b,10c-
dihydropyrene (23). Using the same procedure for cis,trans-styryl
CPD 22 gave (∼100%) cis,trans-styryl DHP 23 as an oily film, which
could not be crystallized: 1H NMR δ 8.72 (d, J = 7.7 Hz, 2H, H-4,10),
8.64 (d, J = 7.7 Hz, 2H, H-1,3), 8.41 (d, J = 7.7 Hz, 2H, H-5,9), 8.27
(d, J = 7.7 Hz, 2H, H-6,8), 8.08 (t, J = 7.6 Hz, 1H, H-2), 7.81 (t, J =
7.7 Hz, 1H, H-7), 7.18 (tt, J = 7.4, 1.0 Hz, 1H, H-25), 7.09 (dd, J = 7.6,
7.4 Hz, 2H, H-21,22), 6.78−6.68 (m, 3H, H-23,24,26), 6.11 (dd, J =
7.8, 0.9 Hz, 2H, H-17,18), 5.99 (dd, J = 7.8, 1.4 Hz, 2H, H-19,20), 4.31
(d, J = 12.9 Hz, 1H, H-13), 3.22 (d, J = 15.8 Hz, 1H, H-14), 0.83 (d,
J = 15.9 Hz, H-12), 0.41 (d, J = 12.9 Hz, 1H, H-11); 13C NMR δ 136.5
(C-15), 136.3 (C-16), 134.0 (C-3a,10a), 133.7 (C-5a,10d), 128.6
(C-17,18), 127.8 (C-23,24), 127.2 (C-13), 126.9 (C-5,9), 126.6 (C-26),
126.1 (C-21,22,25), 125.8 (C-6,8), 125.6 (C-19,20), 125.3 (C-4,10),
124.8 (C-14), 124.2 (C-1,3), 124.0 (C-7), 123.7 (C-2), 122.6 (C-11),
120.2 (C-12), 37.3 (C-10b), 15.0(C-10c); IR ν (thin film) 3028, 1733,
1597, 1490, 1441, 1355, 1070, 958, 836, 738, 693, 599 cm−1; UV−vis
(dichloromethane) λmax nm (εmax) 256 nm (20000), 348 (54800), 389
(25300), 478 (5780), 609 (106).
6H, H-27−32), 6.81−6.77 (m, 4H, 23−26), 6.59 (d, J = 7.4 Hz, 4H,
H-4,6,12,14), 5.96 (d, J = 12.4 Hz, 2H, H-19,20), 5.84 (s, 4H,
1,2,9,10), 5.80 (d, J = 12.4 Hz, 2H, H-17,18); 13C NMR (CD2Cl2) δ
141.9 (C-8,16), 139.1 (C-21,22), 138.6 (3,7,11,15), 132.7 (C-
1,2,9,10), 131.6 (C-19,20), 130.2 (C-5,13), 123.0 (C-17,18), 128.8
(C-23−26), 128.2 (C-31,32), 126.8 (C-27−30), 126.6 (C-4,6,12,14);
IR ν (KBr) 3077, 3050, 3005, 1596, 1492, 1448, 1432, 961, 795, 769,
10b,10c-Bis((1E)-2-phenylvinyl)-trans-10b,10c-dihydropyrene
(25). From the trans−trans-styryl CPD 24 using the same thermolysis
procedure gave 100% of the trans,trans-styryl DHP 25 as dark green
1
crystals from cyclohexane: mp 232−234 °C; H NMR δ 8.85 (s, 4H,
H-4,5,9,10), 8.67 (d, J = 7.7 Hz, 4H, H-1,3,6,8), 8.08 (t, J = 7.7 Hz,
2H, H-2,7), 6.76−6.69 (m, 6H, H-21−26), 6.03 (dd, J = 8.0, 2.5 Hz,
4H, H-17−20), 3.22 (d, J = 15.8 Hz, 2H, H-13,14), 0.87 (d, J = 15.8
Hz, 2H, H-11,12); 13C NMR δ 136.3 (C-15,16), 133.9 (C-
3a,5a,10a,10d), 127.9 (C-21−24), 126.6 (C-25,26), 125.7 (C-17,20),
125.6 (C-4,5,9,10), 124.6 (C-1,3,6,8), 124.6 (C-13,14), 124.0 (C-2,7),
120.8 (C-11,12), 35.9 (C-10b,10c); IR ν (KBr) 3027, 1654, 1636,
1492, 1447, 959, 838, 774, 735, 717, 690 cm−1; UV−vis (cyclohexane)
λmax nm (εmax) 257 nm (47900), 342 (58000), 380 (26400), 466
(5770), 597 (165).
736, 702, 696, 646, 597 cm−1; UV−vis (cyclohexane) λmax nm (εmax
)
257 (28900), 280 (23900), 389 (3700); EIMS m/z 408 (M+); HRMS
calcd for C32H24 408.1878, found 408.1884. On attempted melting
point determination CPD 20 converted into DHP 21.
Eluted second was the cis−trans or 8-(1E),16-(1Z) isomer 22 as
132 mg (35.4%) of pale yellow crystals from cyclohexane: 1H NMR δ
7.24−7.00 (m, 8H, 23,24, 27−32), 7.13 (t, J = 7.4 Hz, 1H, H-13),
6.83−6.80 (m, 2H, H-25,26), 7.00 (t, J = 7.4 Hz, 1H, H-5), 6.81 and
6.73 (AB, J = 16.3 Hz, H-17,19), 6.72 (d, J = 7.4 Hz, 2H, H-12,14),
6.45 (d, J = 7.4 Hz, 2H, H-4,6), 6.33 (d, J = 11.4 Hz, H-1,10), 6.06 (d,
J = 12.5 Hz, 1H, H-20), 5.97 (d, J = 11.4 Hz, 2H, H-2,9), 5.92 (d, J =
12.5 Hz, 1H, H-18); 13C NMR δ 146.1 (C-16), 140.1 (C-8), 138.8 (C-
22), 138.6 (C-3,7), 138.1 (C-21), 136.2 (C-11,15), 133.3 (C-19),
133.0 (C-1,10), 132.7 (C-2,9), 131.5 (C-20), 130.3 (C-5), 129.5 (C-
18), 128.82 (C-13), 128.75 (C-17), 128.6 (25,26), 126.8 (C-12,14),
126.3 (C-4,6); IR ν (thin film) 3020, 1597, 1574, 1493, 1448, 960,
793, 763, 737, 691 cm−1; UV−vis (cyclohexane) λmax nm (εmax) 252
(29300), 282 (26500), 408 (1600); EIMS m/z 408 (M+); HRMS
calcd for C32H24 408.1878, found 408.1884. On attempted melting
point determination CPD 22 converted into DHP 23.
8,16-Bis(2-(4-nitrophenyl)ethenyl)-1,9-bis(methylthio)-anti-[2.2]-
metacyclophane (38). To a suspension of 4-nitrobenzyltriphenyl-
phosphonium bromide (4.0 g, 8.4 mmol, commercial supplier) in
toluene (50 mL) was added potassium tert-butoxide (1.3g, 12 mmol),
the mixture was heated at 50 °C for 1 h, and then 8,16-diformyl-
(methylthio)cyclophane 22 (1.0 g, 2.81 mmol) was added. The
mixture was heated to reflux over a period of 6 h and stirred overnight.
The toluene was then evaporated, and the crude was extracted with
water and dichloromethane. The organic layer was dried and
evaporated. The residue was chromatographed over silica gel using
dichloromethane−hexane (55:45) as eluent and gave 0.90 g (54%) 38
as a yellow orange mixture of isomers: 1H NMR δ 8.14 (d, J = 8.7 Hz),
7.99−7.96 (m), 7.94 (d, J = 8.6 Hz), 7.90−7.76 (m), 7.42−7.05 (m),
6.51−6.31 (m), 6.02−5.90 (m), 5.42−5.20 (m), 4.43−4.23 (m), 3.96−
3.85 (m), 3.17−3.05 (m), 2.98 (dd, J = 12.5, 3.9 Hz), 2.87 (t, J = 12.2
Hz), 2.68 (t, J = 12.5 Hz), 2.55−2.45 (m), 2.17, 2.11 (4s), 1.63 (s),
1.62 (s), 1.52 (s), 1.47 (s), 1.46 (s); HRMS calcd for C34H30N2O4S2
594.1647, found 594.1657. These mixed isomers were used directly in
the next step.
8,16-Bis(2-(4-nitrophenyl)ethenyl)-1,9-bis(methylthio)-anti-[2.2]-
metacyclophane Bis-sulfonium Salt (42). Using the same procedure
as for 33, the mixed isomers of 38 (900 mg, 1.50 mmol) on reaction
with Borch reagent ((80% oil, 0.9 g, 4.4 mmol) in CH2Cl2 (22 mL)
gave 1.20 g (quantitative) of bis-sulfonium salt 42: 1H NMR (DMSO-
d6) δ 8.22 (m), 7.89−7.39 (m), 6.61−6.19 (m), 4.60−4.54 (m), 4.32
(d, J = 12.6 Hz), 4.18 (d, J = 12.4 Hz), 3.44−3.32 (m), 3.26 (s), 3.25
(s), 3.23 (s), 3.20 (s), 2.95 (s), 2.94 (s), 2.92 (s), 2.87 (s), 2.81 (s).
These were used in the next step.
Eluted third was 67 mg (18%) of the trans−trans or bis-(1E)
1
isomer 24: H NMR δ 7.22−7.02 (m, 10H, H-23−32), 7.0 (t, J = 7.4
Hz, 2H, H-5,13), 6.86 (s, 4H, H-17−20), 6.62 (d, J = 7.4 Hz, 4H, H-
4,6,12,14), 6.48 (s, 4H, H-1,2,9,10); 13C NMR δ 144.6 (C-8,16), 138.2
(C-21,22), 136.7 (C-3,7,11,15), 133.6 (C-19,20), 133.3 (C-1,2,9,10),
129.3 (C-5,13), 128.8 (C-17,18), 127.4 (C-31,32), 127.0 (C-
4,6,12,14), 126.8 (C-27,28,29,30), 126.5 (C-23,24,25,26); IR ν
(KBr) 3026, 1598, 1492, 1447, 959, 838, 774, 763, 736, 690 cm−1;
UV−vis (cyclohexane) λmax nm (εmax) 258 (33000), 284 (33400), 308
(30300), 411 sh (1900). On attempted melting point determination
CPD 24 converts into DHP 25.
10b,10c-Bis((1Z)-2-phenylvinyl)-trans-10b,10c-dihydropyrene
(21). Thermolysis of cis,cis- styryl CPD 20, exactly as described for 12
above, gave 100% yield of the cis,cis-DHP 21 as orange crystals from
1
cyclohexane: mp 152−154 °C; H NMR (CD2Cl2) δ 8.26 (s, 4H,
H-4,5,9,10), 8.21 (d, J = 7.5 Hz, 4H, H-1,3,6,8), 7.78 (t, J = 7.5 Hz,
2H, H-2,7), 7.15 (tt, J = 6.5, 1.1 Hz, 2H, H-25,26), 7.07−7.02 (m, 4H,
671
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Article
Bis-2-(4-nitrophenyl)vinyl)-anti-[2.2]metacyclophane-1,9-dienes
(49−51). Using the same procedure as for 12, reaction of bis-
sulfonium salt 42 (1.20 g, 1.5 mmol) and t-BuOK (600 mg, 5.4 mmol)
in THF (10 mL) gave 350 mg (90%) of a mixture of cyclophanedienes
49−51. The residue was chromatographed over silica gel using
hexanes/CH2Cl2 (60:40) as eluent. Eluted first was mostly the (ZZ)-
isomer 49 (∼75% pure). Washing the crystals with CH2Cl2 yielded 88
mg (23%) of pure (ZZ)-isomer as orange crystals: 1H NMR δ 7.94 (d,
J = 8.8 Hz, 4H, H-23,25,29,31), 7.23 (t, J = 7.4 Hz, 2H, H-5,13), 6.91
(d, J = 8.8 Hz, 4H, H-22,26,28,32), 6.60 (d, J = 7.4 Hz, 4H, H-
4,6,12,14), 6.00 (s, 4H, H-17−20), 5.84 (s, 4H, H-1,2,9,10); 13C NMR
δ 146.2 (C-24,30), 145.8 (C-21,27), 140.8 (C-8,16), 138.2 (C-3,7,11,15),
132.6 (C-18,20), 132.5 (C-1,2,9,10), 130.9 (C-5,13), 129.4 (C-17,19),
129.2 (C-22,26,28,32), 126.6 (C-4,6,12,14), 123.3 (C-23,25,29,31); IR
ν (KBr) 3045, 3008, 1592, 1512, 1339, 1106, 884, 855, 797, 772, 712 cm−1;
UV−vis (dichloromethane) λmax nm (εmax) 254 (14900), 342 (16400),
423 sh (5800); EIMS m/z 498 (M+); HRMS calcd for C32H22N2O4
498.1579, found 498.1593; attempted melting point determination
converted CPD 49 into DHP 58.
Eluted second was 175 mg (45%) of the (ZE)-isomer 50 as orange
red crystals from dichloromethane: 1H NMR δ 8.13 (d, J = 8.8 Hz, 2H,
H-29,31), 7.96 (d, J = 8.8 Hz, 2H, H-23,25), 7.30 (d, J = 8.8 Hz, 2H,
H-28,32), 7.20 (t, J = 7.4 Hz, 1H, H-5), 6.98 (t, J = 7.4 Hz, 1H, H-13),
6.96 (d, J = 8.8 Hz, 2H, H-22,26), 6.95 (d, J = 16.2 Hz, 1H, H-19),
6.86 (d, J = 16.2 Hz, 1H, H-20), 6.76 (d, J = 7.4 Hz, 2H, H-4,6), 6.45
(d, J = 7.4 Hz, 2H, H-12,14), 6.38 (d, J = 11.4 Hz, 2H, H-2,9), 6.10 (s,
2H, H-17,18), 6.00 (d, J = 11.4 Hz, 2H, H-1,10); 13C NMR δ 146.7
(C-30), 146.3 (C-24), 145.8 (C-21), 144.8 (C-8), 144.3 (C-27),
139.6 (C-16), 138.6 (C-11,15), 136.9 (C-3,7), 133.3 (C-2,9), 133.08
(C-1,10), 132.7 (C-18), 132.3 (C-19), 130.9 (C-13), 130.7 (C-20),
130.1 (C-5), 129.6 (C-17), 129.2 (C-22,26), 127.1 (C-4,6), 126.9
(C-28,32), 126.6 (C-12,14), 124.1 (C-29,31), 123.4 (C-23,25); IR ν
(KBr) 3007, 1592, 1512, 1339, 1108, 855, 795, 772, 711 cm−1; UV−vis
(dichloromethane) λmax nm (εmax) 258 (32100), 340 (25000), 435 sh
(9300). Attempted melting point determination converted CPD 50
into DHP 59.
H-23,24), 6.26 (d, J = 8.7 Hz, 2H, H-17,18), 6.08 (d, J = 9.0 Hz, 2H,
H-19,20), 4.23 (d, J = 13.1 Hz, 1H, H-13), 3.25 (d, J = 15.8 Hz, 1H,
H-14), 0.96 (d, J = 15.8 Hz, 1H, H-12), 0.46 (d, J = 13.1 Hz, 1H,
H-11); 13C NMR δ 146.7 (C-25), 146.2 (C-26), 143.8 (C-15), 142.7
(C-16), 133.5 (C-3a,10a), 133.1 (C-5a,10d), 129.2 (C-17,18), 127.2
(C-5,9), 126.09 (C-19,20), 126.06 (C-6,8), 125.6 (C-4,10), 125.1
(C-12), 125.0 (C-13), 124.8 (C-1,3), 124.4 (C-2), 124.3 (C-7), 123.9
(C-11), 123.6 (C-14), 123.3 (C-23,24), 121.4 (C-21,22), 37.4 (C-10b),
34.8 (C-10c); IR ν (KBr) 3031, 1595, 1512, 1341, 846 cm−1; UV−vis
(dichloromethane) λmax nm (εmax) 228 (32100), 344 (65800), 387
(25800), 481 (6860), 606 (125).
10b,10c-Bis((1E)-2-(4-nitrophenylvinyl)-trans-10b,10c-dihydro-
pyrene (60). Using the general thermolysis procedure above, (EE)-
CPD 51 (25 mg) gave (EE)-DHP 60 (25 mg, 100%) as dark green
1
crystals from cyclohexane: mp 275−276 °C; H NMR δ 8.88 (s, 4H,
H-4,5,9,10), 8.71 (d, J = 7.6 Hz, 4H, H-1,3,6,8), 8.13 (t, J = 7.6 Hz,
2H, H-2,7), 7.60 (d, J = 8.8 Hz, 4H, H-21−24), 6.12 (d, J = 8.9 Hz,
4H, H-17−20), 3.28 (d, J = 15.7 Hz, 2H, H-13,14), 1.05 (d, J = 15.8
Hz, 2H, H-11,12); The compound was too insoluble to give a
satisfactory 13C NMR spectrum. IR ν (KBr) 3032, 1513, 1340, 1109,
850 cm−1; UV−vis (dichloromethane) λmax nm (εmax) 228 (16700),
340 (45900), 375 (16300), 473 (4800).
8,16-Bis((2-(4-methoxyphenyl)ethenyl)-1,9-bis(methylthio)-anti-
[2.2]metacyclophane (37). Using the same procedure as for the
synthesis of the p-nitro series (49) except that the reaction was heated
to 80 °C overnight from 4-methoxybenzyltriphenylphosphonium bro-
mide (3.89g, 8.4 mmol), potassium tert-butoxide (1.3g, 11.6 mmol),
and diformylcyclophane (1.0g 2.81 mmol), in toluene (50 mL), there
was obtained the cyclophanes 37 (795 mg, 1.4 mmol, 50%) as a
mixture of isomers. Column chromatography over silica gel using
dichloromethane−hexane 4:6 eluted the mixed isomers as a pale
yellow solid: 1H NMR 7.95−7.80 (m), 7.29−7.20 (m), 7.04−6.98
(m), 6.85−6.80 (m), 6.47−6.43 (m), 6.23 (d, J = 8.8 Hz), 6.18 (d, J =
9.0 Hz), 5.85−5.62 (m), 5.09−5.0 (m), 4.36 (dd), 4.09−3.93 (m),
3.801 (s), 3.800 (s), 3.798 (s), 3.66 (s), 3.65 (s), 3.63 (s), 3.62 (s),
3.12−3.00 (m), 2.91 (t), 2.72 (AB, J = 12 Hz), 2.59−2.50 (m), 2.17,
2.16, 2.10, 2.09, 1.64, 1.63, 1.52, 1.45, 1.44 (9 s)); EIMS m/z 564
(M+); HRMS calcd for C36H36O2S2 564.2157, found 564.2169.
8,16-Bis((2-(4-methoxyphenyl)ethenyl)-1,9-bis(methylthio)-anti-
[2.2]metacyclophane Bis-sulfonium Salt (41). Using the same
procedure as for 33, mixed isomers 37 (200 mg, 0.35 mmol) on
reaction with Borch reagent (80% oil, 0.5 g, 2.4 mmol) in CH2Cl2
(5 mL) gave 275 mg (quantitative) of bis-sulfonium salt 41: 1H NMR
(DMSO-d6) 7.84−7.34 (m), 7.25−7.17 (m), 6.99−6.91 (m), 6.63−
6.55 (m), 6.28−5.88 (m), 4.62−4.52 (m), 3.77, 3.62 (2 s), 3.48−3.20
(6 s), 2.97, 2.94, 2.92 (3 s), 2.36, 2.34, 2.24, 2.23, 1.99 (5 s), which
were used directly in the next step.
Eluted third was 86 mg (22%) of the (EE)-isomer 51 as red crystals:
1H NMR δ 8.17 (d, J = 8.8 Hz, 4H, H-23,25,29,31), 7.35 (d, J =
8.8 Hz, 4H, H-22,26,28,32), 7.05 (d, J = 16.2 Hz, 2H, H-17,19), 7.00
(t, J = 7.4 Hz, 2H, H-5,13), 6.96 (d, J = 16.2 Hz, 2H, H-18,20), 6.63
(d, J = 7.4 Hz, 4H, H-4,6,12,14), 6.55 (s, 4H, H-1,2,9,10); 13C NMR δ
146.8 (C-24,30), 144.4 (C-21,27), 143.7 (C-8,16), 137.0 (C-3,7,11,15),
133.8 (C-1,2,9,10), 132.5 (C-17,19), 131.1 (C-18,20), 130.3 (C-5,13),
127.3 (C-4,6,12,14), 127.0 (C-22,26,28,32), 124.1 (C-23,25,29,31); IR
ν (KBr) 3046, 1588, 1507, 1335, 1108, 965, 863, 817, 761, 745, 688
cm−1; UV−vis (dichloromethane) λmax nm (εmax) 240 (27000), 258
(25400), 285 sh (18100), 369 (28800), 444 sh (13400). Attempted
melting point determination converted CPD 51 into DHP 60.
10b,10c-Bis((1Z)-2-(4-nitrophenyl)vinyl)-trans-10b,10c-dihydro-
pyrene (58). Using the general thermolysis procedure above, (ZZ)-
CPD 49 gave (ZZ)-DHP 58 quantitatively as orange crystals from
dichloromethan: mp 243−244 °C; 1H NMR δ 8.28 (s, 4H, H-
4,5,9,10), 8.25 (d, J = 7.5 Hz, 4H, H-1,3,6,8), 7.94 (d, J = 8.6 Hz, 4H,
H-21−24), 7.86 (t, J = 7.6 Hz, 2H, H-2,7), 6.20 (dd, J = 8.7, 0.8 Hz,
4H, H-17−20), 4.18 (d, J = 13.2 Hz, 2H, H-13,14), 0.38 (d, J = 13.2
Hz, 2H, H-11,12); 13C NMR δ 146.6 (C-25,26), 143.8 (C-15,16),
133.4 (C-3a,5a,10a,10d), 129.2 (C-17−20), 126.9 (C-4,5,9,10), 125.9
(C-1,3,6,8), 125.2 (C-13,14), 124.3 (C-2,7), 123.4 (C-11,12), 121.4
(C-21−24), 36.1 (C-10b,10c); IR ν (KBr) 3074, 3036, 1598, 1515,
Bis-2-(4-methoxyphenyl)vinyl)-anti-[2.2]metacyclophane-1,9-di-
enes (46−48). Using the same procedure as for 12, reaction of bis-
sulfonium salt 41 (200 mg, 0.26 mmol) and t-BuOK (250 mg, 2.2
mmol) in THF (10 mL) gave a mixture of cyclophanedienes 46−48.
The residue was chromatographed over silica gel using hexanes/DCM
60:40. Eluted first was 19 mg (16%) of the (ZZ) isomer 46 as colorless
1
crystals: H NMR δ 7.15 (t, J = 7.3 Hz, 2H, H-5,13), 6.74 (d, J =
8.7 Hz, 4H, H-22,26,28,32), 6.61 (d, J = 8.7 Hz, 4H, H-23,25,29,31),
6.57 (d, J = 7.3 Hz, 4H, H-4,6,12,14), 5.91 (d, J = 12.4 Hz, 2H, H-
18,20), 5.86 (s, 4H, H-1,2,9,10), 5.73 (d, J = 12.4 Hz, 2H, H-17,19),
3.74 (s, 6H, H-33,34); 13C NMR δ 158.3 (C-24,30), 141.9 (C-8,16),
138.2 (C-3,7,11,15), 132.4 (C-1,2,9,10), 131.4 (C-21,27), 130.9
(C-18,20), 129.7 (C-22,26,28,32), 129.6 (C-5,13), 128.3 (C-17,19),
126.2 (C-4,6,12,14), 113.3 (C-23,25,29,31), 55.3 (C-33,34); IR ν
(KBr) 3003, 2835, 1605, 1509, 1458, 1303, 1252, 1178, 1032, 832,
1341, 1107, 854, 842 cm−1; UV−vis (dichloromethane) λmax nm (εmax
)
281 (19500), 348 (46700), 397 (19500), 484 (5160); EIMS m/z 498
(M+); HRMS calcd for C32H22N2O4 498.1580, found 498.1586.
10b-((1E)-2-(4-Nitrophenyl)vinyl)-10c-((1Z)-2-(4-nitrophenyl)-
vinyl)-trans-10b,10c-dihydropyrene (59). Using the general thermol-
ysis procedure above, (ZE)-CPD 50 (25 mg) gave (ZE)-DHP 59
(25 mg, 100%) as olive green crystals from dichloromethane: mp
214−216 °C; 1H NMR δ 8.75 (d, J = 7.8 Hz, 2H, H-4,10), 8.68 (d, J =
7.7 Hz, 2H, H-1,3), 8.40 (d, J = 7.8 Hz, 2H, H-5,9), 8.29 (d, J = 7.7
Hz, 2H, H-6,8), 8.12 (t, J = 7.7 Hz, 1H, H-2), 7.97 (d, J = 8.6 Hz, 2H,
H-21,22), 7.88 (t, J = 7.7 Hz, 1H, H-7), 7.56 (d, J = 9.0 Hz, 2H,
812, 784, 739, 517 cm−1; UV−vis (dichloromethane) λmax nm (εmax
)
228 (46400), 257 (46100), 372 sh (4160); EIMS m/z 468 (M+);
HRMS calcd for C34H28O2 468.2089, found 468.2095. Attempted
melting point determination converted CPD 46 into DHP 55.
Eluted second was 57 mg (47%) of the (ZE) isomer 47 as a pale
yellow solid: 1H NMR δ 7.17 (d, J = 8.8 Hz, 2H, H-22,26), 7.09 (t, J =
7.4 Hz, 1H, H-13), 7.02 (t, J = 7.3 Hz, 1H, H-5), 6.82 (d, J = 8.8 Hz,
2H, H-23,25), 6.78 (d, J = 8.7 Hz, 2H, H-28,32), 6.69 (d, J = 7.4 Hz,
672
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The Journal of Organic Chemistry
Article
2H, H-12,14), 6.68 (AB hidden, 2H, H-17,18), 6.65 (d, J = 8.6 Hz, 2H,
H-29,31), 6.46 (d, J = 7.4 Hz, 2H, H-4,6), 6.32 (d, J = 11.3 Hz, 2H, H-
1,10), 6.00 (d, J = 11.3 Hz, 2H, H-2,9), 5.98 (d, J = 12.3 Hz, 1H, H-
20), 5.79 (d, J = 12.3 Hz, 1H, H-19), 3.82 (s, 3H, H-33), 3.75 (s, 3H,
H-34); 13C NMR δ 159.2 (C-24), 158.3 (C-30), 146.5 (C-16), 140.3
(C-8), 138.6 (C-3,7), 135.9 (C-11,15), 133.1 (C-2,9), 132.8 (C-18),
132.5 (C-2,9), 131.3 (C-27), 131.1 (C-21), 131.0 (C-17), 130.1 (C-5),
129.8 (C-28,32), 128.28 (C-19), 128.24 (C-13), 128.0 (C-22,26),
126.7 (C-12,14), 126.3 (C-4,6), 114.0 (C-23,25), 113.3 (C-29,31),
55.5 (C-33), 55.3 (C-34); IR ν (KBr) 3031, 3001, 2834, 1604, 1509,
1465, 1250, 1175, 1033, 832, 812, 783 cm−1; UV−vis (dichloro-
methane) λmax nm (εmax) 227 (44600), 257 (50000), 283 (36300), 417
sh (4900). Attempted melting point determination converted CPD 47
into DHP 56.
13C NMR (CD2Cl2) δ 159.0 (C-25,26), 134.5 (C-3a,5a,10a,10d),
129.8 (C-15,16), 126.8 (C-17−20), 126.0 (C-4,5,9,10), 124.8
(C1,3,6,8), 124.21 (C-13,14), 124.17 (C-2,7), 119.0 (C-11,12),
113.6 (C-21−24), 55.5 (OMe), 36.4 (C-10b,10c); IR ν (thin film)
3030, 2834, 1606, 1509, 1464, 1440, 1244, 1174, 1034, 959, 842, 815,
736, 704 cm−1; UV−vis (dichloromethane) λmax nm (εmax) 225
(31000), 265 (40200), 343 (46800), 382 (22400), 470 (6400), 606
(130).
8,16-Bis(2-(4-methylphenyl)ethenyl)-1,9-bis(methylthio)-anti-
[2.2]metacyclophane (36). Using the same procedure as for 12,
reaction of diformylmethylthiocyclophane 22 (0.80 g, 2.25 mmol)
with an ylide prepared by reaction of t-BuOK (1.7 g, 15 mmol) and 4-
methylbenzyl triphenylphosphonium bromide (4.5 g, 10 mmol,
commercial supplier) in THF (45 mL), followed by column chroma-
tography using hexanes:dichloromethane (7:3) eluted 685 mg (57%)
of 36 as a mixture of isomers: 1H NMR δ 7.88 (d, J = 7.6 Hz), 7.84 (d,
J = 7.7 Hz), 7.83−7.80 (m), 7.44−6.94 (m), 6.76−6.69 (m), 6.24 (d,
J = 8.2 Hz), 6.20 (d, J = 8.2 Hz), 6.16 (d, J = 8.6 Hz), 6.14 (d, J = 8.3
Hz), 6.10 (d, J = 8.2 Hz), 5.92 (d, J = 12.3 Hz), 5.87 (d, J = 12.4 Hz),
5.82 (d, J = 12.4 Hz), 5.68 (d, J = 16.3 Hz), 5.23 (d, J = 16.3 Hz), 5.10
(d, J = 16.3 Hz), 4.35 (dd, J = 11.5, 4.0 Hz), 4.15−3.95 (m), 3.14−
2.87 (m), 2.75−2.51 (m), 2.36, 2.32, 2.28, 2.26 (4s), 2.17, 2.16, 2.15,
2.12, 2.11, 2.10, 2.03 (7s), 1.61, 1.60, 1.42, 1.40 (s)); EIMS m/z 532
(M+); HRMS calcd for C36H36S2 532.2258, found 532.2253. These
were used directly in the next step.
Eluted third was 27 mg (22%) of the (EE) isomer 48 as pale yellow
1
crystals: H NMR δ 7.20 (d, J = 8.8 Hz, 4H, H-22,26,28,32), 6.98 (t,
J = 7.4 Hz, 2H, H-5,13), 6.84 (d, J = 8.8 Hz, 4H, H-23,25,29,31), 6.76
(AB, hidden, 4H, H-17−20), 6.60 (d, J = 7.4 Hz, 4H, H-4,6,12,14),
6.45 (s, 4H, H-1,2,9,10), 3.83 (s, 6H, OMe); 13C NMR δ 159.2 (C-
24,30), 144.8 (C-8,16), 136.4 (C-3,7,11,15), 133.14 (C-18,20), 133.11
(C-1,2,910), 131.2 (C-21,27), 128.9 (C-23,25,29,31), 128.3 (C-5,13),
128.0 (C-22,26,28,32), 127.0 (C-17,19), 126.9 (C-4,6,12,14), 55.5
(C-33,34); IR ν (KBr) 3031, 3001, 2833, 1604, 1509, 1465, 1438, 1250,
1174, 1034, 966, 810, 770, 753 cm−1; UV−vis (dichloromethane) λmax
nm (εmax) 228 (50600), 263 (45700), 417 sh (6200). Attempted
melting point determination converted CPD 48 into DHP 57.
10b,10c-Bis((1Z)-2-(4-methoxyphenyl)vinyl)-trans-10b,10c-dihy-
dropyrene (55). Using the general thermolysis procedure above, (ZZ)-
CPD 48 (25 mg) gave (ZZ)-p-methoxystyryl DHP 55 (25 mg, 100%)
8,16-Bis(2-(4-methylphenyl)ethenyl)-1,9-bis(methylthio)-anti-
[2.2]metacyclophane Bis- sulfonium salt (40). Using the same
procedure as for 33, mixed isomers 36 (650 mg, 1.21 mmol) on reac-
tion with Borch reagent (80% oil, 1.0 g, 4.8 mmol) in CH2Cl2 (7 mL)
1
1
as orange crystals from dichloromethane: H NMR δ 8.28 (s, 4H,
gave 510 mg (57%) of bis-sulfonium salt 40: H NMR (DMSO-d6) δ
H-4,5,9,10), 8.24 (d, J = 7.6 Hz, 4H, H-1,3,6,8), 7.79 (t, J = 7.6 Hz,
2H, H-2,7), 6.59 (d, J = 8.6 Hz, 4H, H-21−24), 5.92 (d, J = 8.6 Hz,
4H, H-17−20), 4.12 (d, J = 12.8 Hz, 2H, H-13,14), 3.83 (OMe), 0.25
(d, J = 12.8 Hz, 2H, H-11,12); 13C NMR (CD2Cl2) δ 158.6 (C-25,26),
134.3 (3a,5a,10a,10d), 129.8 (C-17−20), 129.1 (C-15,16), 127.3
(C-13,14), 126.8 (C-4,5,9,10), 125.7 (C-1,3,6,8), 124.0 (C-2,7), 122.9
(C-11,12), 111.8 (C-21,24), 55.7 (OMe), 36.8 (10b,10c); IR ν (thin
film) 3030, 2834, 1605, 1574, 1507, 1463, 1243, 1174, 1034, 960, 860,
814, 737, 704 cm−1; UVvis (dichloromethane) λmax nm (εmax) 228
(34600), 351 (47100), 394 (25200), 486 (5500), 619 (140); EIMS m/z
468 (M+); HRMS calcd for C34H28O2 468.2089, found 468.2094.
10b-((1E)-2-(4-Methoxyphenyl)vinyl)-10c-((1Z)-2-(4-methoxyphenyl)-
vinyl)-trans-10b,10c-dihydropyrene (56). Using the general thermol-
ysis procedure above, CPD 47 (25 mg), gave mostly (ZE)-p-meth-
oxystyryl DHP 56 as an olive green solid containing a little of the
(EE)-isomer (total 25 mg): 1H NMR (CD2Cl2) δ 8.72 (d, J = 7.7 Hz,
2H, H-4,10), 8.64 (d, J = 7.7 Hz, 2H, 1,3), 8.44 (d, J = 7.7 Hz, 2H,
H-5,9), 8.31 (d, J = 7.7 Hz, 2H, H-6,8), 8.06 (t, J = 7.7 Hz, 1H, H- 2),
7.83 (t, J = 7.7 Hz, 1H, H-7), 6.62 (d, J = 8.5 Hz, 2H, H-21,22), 6.25
(d, J = 8.8 Hz, 2H, H-23,24), 5.98 (d, J = 8.4 Hz, 2H, H-17,18), 5.89
(d, J = 8.8 Hz, 2H, H-19,20), 4.20 (d, J = 12.8 Hz, 1H, H-13), 3.84 (s,
3H, H-33), 3.48 (s, 3H, H-34), 3.15 (d, J = 15.8 Hz, 1H, H-14), 0.65
(d, J = 15.8 Hz, 1H, H-12), 0.33 (d, J = 12.8 Hz, 1H, H-11); 13C NMR
(CD2Cl2) δ 159.0 (C-26), 158.6 (C-25), 134.4 (C-3a,10a), 134.1 (C-
5a,10d), 129.8 (C-17,18), 127.2 (C-5,9), 127.1 (C-13), 126.8 (C-
19,20), 126.0 (C-6,8), 125.7 (C-4,10), 124.4 (C-1,3), 124.3 (C-14),
124.2 (C-7), 123.9 (C-2), 123.4 (C-11), 118.3 (C-12), 113.6 (C-
23,24), 111.9 (C-21,22), 55.7 (C-33), 55.5 (C-34), 37.7 (C-10b), 35.6
(C-10c); IR ν (thin film) 3030, 2834, 1606, 1509, 1464, 1440, 1244,
1174, 1034, 959, 842, 815, 736, 704 cm−1; UV−vis (dichloromethane)
λmax nm (εmax) 225 (24300), 264 (32300), 346 (42100), 387 (21200),
472 (5400), 607 (120).
7.83 (d, J = 7.7 Hz), 7.75 (d, J = 7.6 Hz), 7.71−7.50 (m), 7.47 (t, J =
7.6 Hz), 7.20−7.10 (m), 6.86−6.76 (m), 6.24−6.05 (m), 6.00−5.87
(m), 5.46 (d, J = 16.4 Hz), 5.30 (d, J = 16.6 Hz), 4.53 (br d), 4.26−
3.97 (m), 3.30, 3.22, 3.21, 3.20, 3.18 (s), 2.98−2.78 (m), 2.30, 2.28
(3 s), 2.18, 2.10, 1.96 (4 s). These were used in the next step.
Bis-2-(4-methylphenyl)vinyl)-anti-[2.2]metacyclophane-1,9-di-
enes (43−45). Using the same procedure as for 12, reaction of bis-
sulfonium salt 40 (470 mg, 0.63 mmol) and t-BuOK (200 mg, 1.8 mmol)
in THF (8 mL) gave a mixture of cyclophanedienes 43−45. The
residue was chromatographed over silica gel using hexanes:dichloro-
methane (90:10). Eluted first was 116 mg (42%) (ZZ)-CPD 43 as
1
colorless crystals: H NMR δ 7.16 (t, J = 7.3 Hz, 2H, H-5,13), 6.88
(d, J = 8.0 Hz, 4H, H-23,25,29,31), 6.70 (d, J = 8.0 Hz, 4H,
H-22,26,28,32), 6.57 (d, J = 7.3 Hz, 4H, H-4,6,12,14), 5.94 (d, J = 12.4
Hz, 2H, H-18,20), 5.85 (s, 4H, H-1,2,9,10), 5.78 (d, J = 12.4 Hz, 2H,
H-17.19), 2.25 (s, 6H, Me); 13C NMR δ 141.8 (C-8,16), 138.2
(C-3,7,11,15), 136.0 (C-24,30). 135.8 (C-21,27), 132.4 (C-1,2,9,10),
131.3 (C-18,20), 129.6 (C-5,13), 128.9 (C-17,19), 128.6 (C-23,25,29,31),
128.4 (C-22,26,28,32), 126.1 (C-4,6,12,14), 21.4 (C-33,34); IR ν
(KBr) 3041, 3015, 3003, 1560, 1508, 1370, 1405, 1151, 859, 817, 782,
749, 737, 594 cm−1; UV−vis (cyclohexane) λmax nm (εmax) 257
(30100), 277 (24000), 392 (3300); EIMS m/z 436 (M+); HRMS
calcd for C34H28 436.2191, found 436.2205. Attempted melting point
determination converted CPD 43 into DHP 52.
Eluted second was 105 mg (38%) of the (ZE)-isomer 44 as pale
yellow crystals from cyclohexane: 1H NMR δ 7.12 (d, J = 8.3 Hz, 2H,
H-22,26), 7.10 (t, J = 7.5 Hz, 1H, H-13), 7.08 (d, J = 8.4 Hz, 2H,
H-23,25), 7.01 (t, J = 7.4 Hz, 1H, H-5), 6.90 (d, J = 8.0 Hz, 2H,
H-29,31), 6.86−6.73 (m, 4H, H-17,18,28,32), 6.71 (d, J = 7.4 Hz,
2H, H-12,14), 6.47 (d, J = 7.4 Hz, 2H, H-4,6), 6.33 (d, J = 11.3 Hz,
2H, H-1,10), 6.02 (d, J = 12.3 Hz, H-20), 6.00 (d, J = 11.4 Hz, 2H, H-
2,9), 5.83 (d, J = 12.3 Hz, 1H, H-19). 2.34 (s, 3H, H-33), 2.26 (s, 3H,
H-34); 13C NMR δ 146.3 (C-16), 140.2 (C-8), 137.2 (C-24), 138.6
(C-3,7), 136.09 (C-30), 136.07 (C-11,15), 135.8 (C-27), 133.2
(C-18), 133.0 (C-1,10), 132.6 (C-2,9), 131.5 (C-20), 130.2 (C-5),
129.2 (C-13), 128.9 (C-19), 128.6 (C-29,31), 128.5 (C-28,32), 127.8
(C-17), 126.8 (C-12,14), 126.7 (C-22,26), 126.3 (C-4,6), 21.5 (C-33),
21.4 (C-34) IR ν (thin film) 3045, 3019, 3005, 1510, 1436, 1265, 963,
868, 816, 805, 786, 777, 746, 702, 647 cm−1; UV−vis (cyclohexane)
10b,10c-Bis((1E)-2-(4-methoxyphenylvinyl)-trans-10b,10c-dihy-
dropyrene (57). Using the general thermolysis procedure above, CPD
48 (25 mg) gave p-methoxystyryl DHP 57 (25 mg, 100%) was
obtained as a dark green oily solid, which would not crystallize:
1H NMR (CD2Cl2) δ 8.88 (s, 4H, H-4,5,9,10), 8.70 (d, J = 7.7 Hz, 4H,
1,3,6,8), 8.10 (t, J = 7.7 Hz, 2H, H-2,7), 6.28 (d, J = 8.8 Hz, 4H,
H-21−24), 5.95 (d, J = 8.8 Hz, 4H, H-17−20), 3.51 (OMe), 3.17 (d,
J = 15.8 Hz, 2H, H-13,14), 0.70 (d, J = 15.8 Hz, 2H, H-11,12);
673
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λmax nm (εmax) 252 (60000), 280 (48400), 413 sh (6600). Attempted
melting point determination converted CPD 44 into DHP 53.
Eluted third was 30 mg (11%) of the (EE)-isomer 45 as pale yellow
8,16-Bis(4-methylpenta-1,3-dienyl)-1,9-bis(methylthio)-anti-
[2.2]metacyclophane (92).
1
crystals: H NMR δ 7.16 (AB, J = 8.1 Hz, 4H, H-22,26,28,32), 7.10
(AB, J = 8.1 Hz, 4H, H-23,25,29,31), 6.98 (t, J = 7.3 Hz, 2H, H-5,13),
6.86 and 6.84 (AB, J = 16.2, 4H, H-17−20), 6.60 (d, J = 7.3 Hz, 4H,
H-4,6,12,14), 6.46 (s, 4H, H-1,2,9,10) 2.34 (s, 6H, Me); 13C NMR δ
144.7 (C-8,16), 137.2 (C-24,30), 136.5 (C-3,7,11,15), 135.5 (C-
21,27), 133.5 (C-18,20), 133.2 (C-1,2,9,10), 129.2 (C-23,25,29,31),
129.1 (C-5,13), 127.9 (C-17,19), 126.9 (C-4,6,12,14), 126.7 (C-
22,26,28,32). 21.5 (C-33,34, Me) ; IR ν (KBr) 3045, 3022, 3003, 1560,
1513, 1458, 1429, 960, 797, 755, 653, 631 cm−1; UV−vis (cyclohexane)
λmax nm (εmax) 257 (53500), 285 (53000), 313 (48700), 410 sh
(6100). Attempted melting point determination converted CPD 45
into DHP 54.
Using the same procedure as for 12, reaction of diformylmethylth-
iocyclophane 22 (680 mg, 1.91 mmol) with an ylide prepared by
reaction of t-BuOK (1.60 g, 14.3 mmol) and 3-methylbut-2-enyltri-
phenylphosphonium bromide (4.2 g, 10.2 mmol) in THF (40 mL),
followed by column chromatography using hexanes/dichloromethane
(75:25) gave 590 mg (67%) of 92 as a mixture of isomers: 1H NMR δ
7.88−7.78 (m), 7.24−6.89 (m), 5.86−5.56 (m), 5.50−5.40 (m), 5.15−
4.91 (m), 4.70−4.56 (m), 4.40−4.32 (m), 4.10−3.95 (m), 3.10−3.00
(m), 2.91−2.83 (m), 2.70−2.50 (m), 2.28 (t, J = 11.4 Hz), 2.19, 2.18
(s), 2.13, 2.09 (3 s), 2.06, 2.04, 2.03 (3 s), 1.74, 1.61, 1.60 (br s), 1.53,
1.51 (br s)); EIMS m/z 460 (M+); HRMS calcd for C30H36S2
460.2258, found 460.2257. These were used directly in the next step
8,16-Bis(4-methylpenta-1,3-dienyl)-1,9-bis(methylthio)-anti-
[2.2]metacyclophane Bis-sulfonium Salt (93).
10b,10c-Bis((1Z)-2-(4-methylphenyl)vinyl)-trans-10b,10c-dihy-
dropyrene (52). Using the general thermolysis procedure above, (ZZ)-
CPD 43 (25 mg) gave (ZZ)-p-methylstyryl DHP 52 (25 mg, 100%) as
1
orange crystals from cyclohexane: H NMR (CD2Cl2) δ 8.25 (s, 4H,
H-4,5,9,10), 8.22 (d, J = 7.5 Hz, 4H, H-1,3,6,8), 7.78 (t, J = 7.5 Hz,
2H, H-2,7), 6.84 (d, J = 7.6 Hz, 4H, H-21−24), 5.89 (d, J = 7.5 Hz,
4H, H-17−20), 4.17 (d, J = 12.9 Hz, 2H, H-13,14), 2.34 (s, 6H, Me)
0.25 (d, J = 12.9 Hz, 2H, H-11,12); 13C NMR (CD2Cl2) δ 135.8 (C-
25,26), 134.2 (C-3a,5a,10a,10d), 133.7 (C-15,16), 128.6 (17−20),
127.5 (C-13,14), 127.0 (C-21−24), 126.9 (C-4,5,9,10), 125.7 (C-
1,3,6,8), 124.0 (C-2,7), 122.5 (C-11,12), 36.7 (C-10b,10c), 21.5 (Me);
IR ν (KBr) 3038, 3019, 1507, 1345, 860, 836, 607 cm−1; UV−vis
(cyclohexane) λmax nm (εmax) 227 (37500), 353 (68800), 396 (33300),
490 (6300), 624 (130); EIMS m/z 436 (M+); HRMS calcd for C34H28
436.2191, found 436.2197.
10b-((1E)-2-(4-Methylphenyl)vinyl)-10c-((1Z)-2-(4-methylphenyl)-
vinyl)-trans-10b,10c-dihydropyrene (53). Using the general thermol-
ysis procedure above, (ZE)-CPD 44 (25 mg) gave (ZE)-p-methyl-
styryl DHP 53 (25 mg, 100%) as an olive green oily film which could
Using the same procedure as for 33, mixed isomers of 92 (0.55 g, 1.2
mmol) on reaction with Borch reagent ((80% oil, 0.9 g, 4.4 mmol) in
CH2Cl2 (8 mL) gave 320 mg (41%) of bis-sulfonium salt 93: 1H NMR
(DMSO-d6) 7.77−7.32 (m), 7.26 (t, J = 7.6 Hz), 7.10 (t, J = 7.5 Hz),
6.08−5.92 (m), 5.82−5.71(m), 5.06 (t, J = 12.2 Hz), 4.93−4.74 (m),
4.63−4.42 (m), 4.18 (d, J = 11.2 Hz), 4.12 (d, J = 11.7 Hz) 4.04 and
4.02 (AB, J = 14.2, 7.0 Hz), 3.9 (d, J = 11.2 Hz), 3.52−3.10 (m), 3.32−
3.29 (overlapping singlets), 2.91−2.76 (6 s), 1.75, 1.64, 1.62, 1.57,
1.55, 1.52 (br s). These were used in the next step.
1
not be crystallized: H NMR (CD2Cl2) δ 8.72 (d, J = 7.7 Hz, 2H, H-
4,10), 8.63 (d, J = 7.7 Hz, 2H, H-1,3), 8.41 (d, J = 7.7 Hz, 2H, H-5,9),
8.28 (d, J = 7.7 Hz, 2H, H-6,8), 8.06 (t, J = 7.7 Hz, 1H, H-2), 7.82 (t, J =
7.7 Hz, 1H, H-7), 6.89 (d, J = 7.7 Hz, 2H, H-21,22), 6.51 (d, J = 8.1,
2H, H-23,24), 5.95 (d, J = 7.4 Hz, 2H, H-17,18), 5.84 (d, J = 8.3 Hz,
2H, H-19,20), 4.22 (d, J = 12.8 Hz, 1H, H-13), 3.17 (d, J = 15.9 Hz,
1H, H-14), 2.36 (s, 3H, H-33), 1.96 (s, 3H, H-34), 0.73 (d, J =
15.9 Hz, 1H, H-12), 0.32 (d, J = 12.9 Hz, 1H, H-11); 13C NMR
(CD2Cl2) δ 136.9 (C-26), 135.9 (C-25), 134.4 (C-3a,10a), 134.1
(C-5a,10d), 133.7 (C-15), 133.6 (C-16), 128.9 (C-23,24), 128.7
(C-17,18), 127.4 (C-13), 127.3 (C-5,9), 127.1 (C-21,22), 126.1
(C-6,8), 125.5 (C-19,20), 124.9 (C-14), 124.4 (C-1,3), 124.3 (C-7),
123.9 (C-2), 122.9 (C-11), 119.6 (C-12), 37.7 (C-10b), 35.5 (C-10c),
21.5 (C-33), 21.0 (C-34); IR ν (thin film) 3025, 2921, 2851, 1637,
1512, 1458, 1123, 962, 840, 801, 711 cm−1; UV−vis (dichloro-
methane) λmax nm (εmax) 227 (24500), 257 (28900), 347 (42900), 387
(19100), 478 (4300), 607 (100).
10b,10c-Bis((1E)-2-(4-methylphenylvinyl)-trans-10b,10c-dihydro-
pyrene (54). Using the general thermolysis procedure above, (EE)-
CPD 45 (25 mg) gave (EE)-p-methylstyryl DHP 54 (25 mg, 100%) as
a dark green oily solid which could not be crystallized: 1H NMR
(CD2Cl2) δ 8.88 (s, 4H, H-4,5,9,10), 8.69 (d, J = 7.6 Hz, 4H,
H-1,3,6,8), 8.10 (t, J = 7.6 Hz, 2H, H-2,7), 6.55 (d, J = 8.2 Hz, 4H,
H-21−24), 5.89 (d, J = 8.2 Hz, 4H, H-17−20), 3.19 (d, J = 15.8 Hz,
2H, H-13,14), 1.99 (s, Me), 0.79 (d, J = 15.8 Hz, 2H, H-11,12);
13C NMR (CD2Cl2) δ 137.0 (C-25,26), 134.4 (C-3a,5a,10a,10d),
133.5 (C-15,16), 128.9 (C-21−24), 126.0 (C-4,5,9,10), 125.6 (C-17−
20), 124.9 (C-1,3,6,8), 124.7 (C-13,14), 124.3 (C-2,7), 120.1 (C-
11,12), 36.3 (C-10b,10c) 21.0 (Me); IR ν (KBr) 3025, 2921, 2851,
1637, 1512, 1458, 962, 840, 801, 711 cm−1; UV−vis (dichloro-
methane) λmax nm (εmax) 227 (19100), 259 (33700), 343 (40300), 380
(21000), 468 (5400), 593 (170).
8,16-Bis(4-methylpenta-1,3-dienyl)-anti-[2.2]metacyclophane-
1,9-dienes (62−64). Using the same procedure as for 12, reaction of
bis-sulfonium salt 93 (300 mg, 1.05 mmol) and t-BuOK (400 mg,
3.6 mmol) in THF (20 mL) gave a mixture of cyclophanedienes (325
mg, 85%, approximately 1:1:1 isomer mixture), which was chromato-
graphed over silica gel using hexanes/dichloromethane (19:1). Eluted
first from column was a mixture of (EE)-isomer 64 and (ZE)-63 and
then last 63 and the (ZZ)-isomer 62. Although the isomers could not
be obtained completely free of each other, their spectral properties
could be obtained:
1
(EE)-Isomer 64: H NMR (CD2Cl2) δ 6.98 (t, J = 7.4 Hz, 2H, H-
5,13), 6.80 (dd, J = 15.3, 11.0 Hz, 2H, H-19,20), 6.53 (d, J = 7.4 Hz,
4H, H-4,6,12,14), 6.38 (s, 4H, H-1,2,9,10), 6.09 (d, J = 15.4 Hz, 2H,
H-17,18), 5.60 (dm, J = 10.8 Hz, 2H, H-21,22), 1.78 (s, 6H, H-25,28),
1.72 (s, 6H, H-26,27); 13C NMR (CD2Cl2) δ 146.0 (C-8,16), 136.4
(C-3,7,11,15), 136.3 (C-23,24), 133.5 (C-1,2,9,10), 130.9 (C-19,20),
129.8 (C-17,18), 129.0 (C-5,13), 127.1 (C-21,22), 126.9 (C-4,6,12,14),
26.5 (C-25,28), 18.7 (C-26,27); EIMS m/z 364 (M+); HRMS calcd
for C28H28 364.2191, found 364.2195.
1
(EZ)-Isomer 63: H NMR (CD2Cl2) δ 7.09 (t, J = 7.4 Hz, 1H,
H-13), 6.99 (t, J = 7.4 Hz, 1H, H-5), 6.75 (dd, J = 15.2, 11.0 Hz, 1H,
H-20), 6.58 (d, J = 7.4 Hz, 2H, H-12,14), 6.57 (d, J = 7.4 Hz, 2H, H-
4,6), 6.33 and 6.31 (AB, J = 11.4 Hz, 4H, H-1,2,9,10), 6.04 (d, J = 15.4
Hz, 1H, H-18), 6.00−5.95 (m, 1H, H-21), 5.83 (dd, J = 12.4, 11.8 Hz,
1H, H-19), 5.79 (d, J = 12.4 Hz, 1H, H-17), 5.60 (dm, J = 12.5 Hz,
1H, H-22), 1.78 (s, 3H, H-28), 1.74 (s, 3H, H-25), 1.72 (s, 3H, H-27),
1.71 (s, 3H, H-26); 13C NMR (CD2Cl2) δ 147.1 (C-8), 142.4 (C-16),
138.2 (C-11,15), 137.4 (C-23), 136.5 (C-24), 136.2 (C-3,7), 133.1
(C-2,9), 133.0 (C-1,10), 130.9 (C-20), 129.8 (C-13), 129.6 (C-18),
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128.4 (C-5), 127.1 (C-22), 126.89 (C-4,6), 126.87 (C-17), 126.42
(C-19), 126.40 (C-12,14), 123.4 (C-21), 26.6 (C-25), 26.5 (C-28),
18.7 (C-27), 18.6 (C-26).
129.2, 128.9, 128.8, 128.7, 128.5, 128.4, 128.0, 127.9, 127.6, 127.5,
127.3, 127.1, 126.3, 125.9, 125.2, 124.9, 123.5, 110.2, 109.5, 109.3,
109.04, 108.96, 87.2, 54.0, 53.5, 53.3, 53.0, 50.7, 46.2, 44.12, 44.05,
43.6, 29.9, 28.4, 22.9, 21.1, 17.6, 17.0, 16.9, 15.9, 15.6, 14.3. This
material was used directly in the next step using the same procedure
used to prepare 33. From these mixed isomers (600 mg) on reaction
with Borch reagent (80% oil, 1.0 g, 4.84 mmol) in CH2Cl2 (7 mL)
1
(ZZ)-Isomer 62. H NMR (CD2Cl2) δ 7.10 (t, J = 7.4 Hz, 2H,
H-5,13), 6.63 (d, J = 7.4 Hz, 4H, H-4,6,12,14), 6.24 (s, 4H, H-
1,2,9,10), 6.00−5.97 (m, 2H, H-21,22), 5.76 (br s, 4H, H-17−20),
1.74 (s, 6H, H-25,28), 1.71 (s, 6H, H-26,27); 13C NMR (CD2Cl2)
δ 143.4 (C-8,16), 137.9 (C-3,7,11,15), 137.6 (C-23,24), 132.6
(C-1,2,9,10), 129.2 (C-5,13), 126.6, 126.5 (C-17−20), 126.3
(C-4,6,12,14), 26.6 (C-25,28), 18.6 (C-26,27); IR (mix) ν (KBr)
3041, 3002, 2965, 2910, 1636, 1560, 426, 1375, 952, 786, 777, 750 cm−1;
UV−vis (cyclohexane) λmax (εmax) 246 (27900), 284 (32600), 390
(5000), 406 sh (4800).
10b,10c-Bis(4-methylpenta-1,3-dienyl)-trans-10b,10c-dihydro-
pyrene Dihydropyrenes (65−67). A mixture of cyclophanedienes
62−64 (45 mg) in toluene-d8 (6 mL) was sealed in a glass tube under
argon and heated at 110 °C for 2 h, which converted it into a mixture
of dihydropyrenes 65−67 (45 mg, approximately 1:1:1). The mixture
was chromatographed over silica gel using hexanes-dichloromethane
(9:1) as eluent. Eluted first was the (EE)-isomer 67, dark green
colored crystals: mp 188−190 °C; 1H NMR δ 8.76 (s, 4H, H-
4,5,9,10), 8.63 (d, J = 7.8 Hz, 4H, H-1,3,6,8), 8.06 (t, J = 7.7 Hz, 2H,
H-2,7), 4.04 (dm, J = 10.9 Hz, 2H, H-15,16), 2.95 (dd, J = 15.0, 10.8
Hz, 2H, H-13,14), 1.15, 1.10 (s, 12H, Me), 0.22 (d, J = 15.0 Hz, 2H,
H-11,12); 13C NMR δ 134.4 (C-3a,5a,10a,10d), 133.5 (C-17,18),
125.3 (C-4,5,9,10), 124.2 (C-1,3,6,8), 123.8 (C-15,16), 123.7 (C-2,7),
121.8 (C-11,12), 121.4 (C-13,14), 35.8 (C-10b,10c), 25.5, 18.0 (C19−
22); IR ν (KBr) 3053, 3029, 3003, 1654, 1648, 1441, 1376, 956, 843,
710 cm−1 ; UV−vis (cyclohexane) λmax nm (εmax) 247 (76200), 338
(78300), 380 (27900), 469 (7900), 609 (135) EIMS m/z 364 (M+);
HRMS calcd for C28H28 364.2191, found 364.2195.
1
there was obtained 600 mg of the bis-sulfonium salt of 68: H NMR
(DMSO-d6) δ 7.81 (d, J = 7.8 Hz), 7.69 (d, J = 7.5 Hz), 7.62 (d, J =
7.6 Hz), 7.52 (d, J = 7.6 Hz), 7.41 (t, J = 7.6 Hz), 7.27 (t, J = 7.2 Hz),
6.41 (d, J = 7.6 Hz), 6.36 (d, J = 7.8 Hz), 6.25 (d, J = 8.0 Hz), 5.08 (d,
J = 7.7 Hz), 4.74 (d, J = 7.8 Hz), 4.57 (dd, J = 11.2, 3.3 Hz), 4.48−4.42
(m), 3.55−3.50 (m), 3.33, 3.32 (2s), 2.86, 2.84 (s), 2.93−2.74 (m).
These were then suspended in THF (20 mL) and t-BuOK (600 mg,
5.35 mmol) was added and the mixture stirred at 20 °C for 2h. Water
and CH2Cl2 were added and the organic extract was washed, dried and
evaporated. Chromatography over silica gel using hexane−CH2Cl2
90:10 gave the colorless diethynyl CPD 69 (100 mg, ∼14% overall).
1
However, the yield was variable from run to run: H NMR δ 7.19 (t,
J = 7.5 Hz, 2H, H-5,13), 6.75 (d, J = 7.5 Hz, 4H, H-4,6,12,14), 6.49
(s, 4H, H-1,2,9,10), 2.84 (H-18,20); 13C NMR δ 141.1 (C-3,7,11,15),
133.9 (C-1,2,9,10), 131.4 (C-5,13), 129.8 (C-8,16), 126.5 (C-4,6,12,14),
834 (C-18,20), 81.8 (C-17,19); IR ν (KBr) 3293, 3050, 3005, 1727,
1427, 1262, 857, 805, 755, 655 cm−1; UV−vis (dichloromethane) λmax
nm (εmax) 235 (35800), 281 (12900); EIMS m/z 252 (M+, 100%);
HRMS calcd for C20H12 252.0939, found 252.0923. On attempted
melting point determination, diethynyl CPD 69 isomerized to
diethynyl DHP 70.
10b,10c-Diethynyl-trans-10b,10c-dihydropyrene (70). Using the
general thermolysis procedure above, diethynyl CPD 69 (25 mg) gave
diethynyl DHP 70 (25 mg, 100%) as dark green crystals from CH2Cl2:
mp 245−250 °C dec; 1H NMR δ 8.88 (s, 4H, H-4,5,9,10), 8.74 (d, J =
7.6 Hz, 4H, H-1,3,6,8), 8.27 (t, J = 7.7 Hz, 2H, H-2,7), −0.09 (s, 2H,
H-12,14); 13C NMR δ 132.9 (C-3a,5a,10a,10d), 125.5 (C-4,5,9,10),
124.6 (C-2,7), 123.8 (C-1,3,6,8), 75.4 (C-11,13), 65.0 (C-12,14), 30.0
(C-10b, 10c); IR ν (KBr) 3264, 3042, 1654, 1353, 845, 756, 662 cm−1;
UV−vis (dichloromethane) λmax nm (εmax) 223 (2900), 229 (7900),
336 (9700), 372 (42700), 399 (4400), 452 (7200), 535 (100), 596
(130), 639 (210); EIMS m/z 252 (M+); HRMS calcd for C20H12
252.0939, found 252.0923.
Eluted second was mostly the (ZE)-isomer 66: 1H NMR δ 8.72 and
8.69 (AB, J = 7.7 Hz, 4H, H-4,5,9,10), 8.69 (d, J = 7.6 Hz, 2H, H-6,8),
8.60 (d, J = 7.8 Hz, 2H, H-1,3), 8.08 (t, J = 7.7 Hz, 1H, H-7), 8.04 (t,
J = 7.8 Hz, 1H, H-2), 4.50 (dm, J = 12, 1.3 Hz, 1H, H-15), 4.06 (dm,
J = 10.8 Hz 1H, H-16), 3.84 (t, J = 12.3 Hz, 1H, H-13), 3.03 (dd, J =
15.0, 10.8 Hz, 1H, H-14), 1.52, 1.00 (br s, 6H, H-19,20), 1.16. 1.11
(2s, 6H, H-21,22), 0.23 (d, J = 15.0 Hz, 1H, H-12), 0.01 (d, J = 12.4
Hz, 1H, H-11); 13C NMR 135.9 (C-17,18), 135.3 (C-5a,10d), 134.8
(3a,10a), 126.3 (C-5,9), 125.4 (C-4,10), 125.1 (C-6,8), 124.4 (C-1,3),
123.84 (C-16), 123.78 (C-2), 123.2 (C-7), 122.7 (C-13), 121.9 (C-
14), 120.8 (C-12), 120.0 (C-11), 119.4 (C-15), 37.8 (C-10b), 34.8 (C-
10c), 26.5, 17.1 (C-19,20), 25.5, 18.0 (C-21,22); IR ν (KBr) 3030,
3003, 2926, 2853, 1654, 1438, 1374, 955, 843, 838, 714, 645 cm−1;
UV−vis (cyclohexane) λmax nm (εmax) 250 nm (54800), 344 (56400),
389 (30400), 475 (6058), 614 (120).
6-tert-Butyl-18-cyano-9-methyl-2,11-dithia[3.3]metacyclophanes
(73) and (74). A solution of 2,6-bis(bromomethyl)benzonitrile11 79
(4.40 g, 15.2 mmol) and 2,6 bis(mercaptomethyl)-4-tert-butylto-
luene12 72 (3.80 g, 15.2 mmol) in deaerated benzene (700 mL) was
added dropwise under nitrogen to an ethanolic KOH solution,
prepared by adding KOH (4.83 g) to deaerated water (230 mL) and
ethanol (2090 mL) followed by addition of sodium borohydride (0.9 g).
The drop rate was crucial (∼1 every 3−4 s), and the addition took 44 h.
The solvent was then evaporated and the residue was dissolved in
dichloromethane and was washed with water, dried, and evaporated.
The residue was chromatographed on silica gel using CH2Cl2−hexanes
(35:65) as eluent. Eluted first was 1.90 g (34%) of anti-thiacyclophane
1
Eluted third was mostly the (ZZ)-isomer 65: H NMR δ 8.65 (d,
J = 7.7 Hz, 4H, H-1,3,6,8), 8.62 (s, 4H, H-4,5,9,10), 8.08 (2H, H-2,7),
4.53 (dm, J = 12.2, 1.4 Hz, 2H, H-15,16), 3.90 (dd, J = 12.2 Hz, 2H,
H-13,14), 1.52, 1.01 (s, 12H, Me), −0.02 (d, J = 12.5 Hz, 2H,
H-11,12); 13C NMR δ 136.1 (C-17,18), 135.9 (C-3a,5a,10a,10d),
126.3 (C-4,5,9,10), 125.4 (C-1,3,6,8), 123.5 (C-2,7), 123.3 (C-13,14),
119.4 (C-15,16), 119.0 (C-11,12), 36.6 (C-10b,10c), 26.6, 17.1
(C-19−22); IR ν (KBr) 3023, 2965, 1647, 1654, 1438, 1374, 836, 729
cm−1; UV (cyclohexane) λmax nm (εmax) 251 (42900), 347 (38200),
392 (20100), 486 (5000), 627 (137).
1
74 as colorless crystals from cyclohexane: mp 147−148 °C; H NMR
δ 7.42−7.45 (m, 3H, H-14,15,16), 7.43 (s, 2H, H-5,7), 3.92 and 3.72
(AB, J = 14.4 Hz, 4H, H-1,12), 3.82 and 3.74 (AB, J = 14.0 Hz, 4H, H-
3,10), 1.43 (s, 3H, Me), 1.39 (s, 9H, C(CH3)3); 13C NMR δ 149.3 (C-
6), 141.5 (C-13,17), 136.6 (C-9), 133.5 (C-4,8), 131.9 (C-15), 129.6
(C-14,16), 128.2 (C-5,7), 115.4 (CN), 115.1 (C-18), 34.6 (C(CH3)3),
33.0 (C-3,10), 31.6 (C-1,12), 31.3 (C(CH3)3), 15.4 (C-20); IR ν
(KBr) 3027, 2954, 2217, 1588, 1483, 1464, 1417, 1236, 877, 804, 794,
755 cm−1; UV (cyclohexane) λmax nm (εmax) 297 (1410), 307 (1390);
EIMS m/z 367 (100); HRMS calcd for C22H25NS2 367.1428, found
367.1413. Anal. Calcd: C, 71.89; H, 6.86; N, 3.81. Found: C, 71.52; H,
6.87; N, 3.69.
8,16-Diethynyl-anti-[2.2]metacyclophane-1,9-diene (69). Using
the procedure above for 32, from the ylide prepared by reaction of
t-BuOK (3.0 g, 27 mmol) and bromomethyl triphenylphosphonium
bromide (2.76 g, 6.3 mmol) in THF (25 mL) and diformylmethylth-
iocyclophane 22 (1.0 g, 2.81 mmol) and column chromatography
using hexanes: dichloromethane (7:3) there was obtained 600 mg (see
1
below for yield) of a mixture of isomers containing 68: H NMR δ
7.86 (d, J = 7.6 Hz), 7.84 (d, J = 7.7 Hz), 7.67−7.62 (m), 7.55−7.52
(m), 7.47−7.41 (m), 7.30−7.25 (m), 7.19 (t, J = 7.5 Hz), 7.06 (t, J =
7.3 Hz), 5.83−5.73 (m), 4.58 (d, J = 7.8 Hz), 4.54 (d, J = 7.6 Hz), 3.89
(dd, J = 11.5, 4.0 Hz), 3.80 (dd, J = 711.5, 3.9 Hz), 3.17−3.13 (m),
2.55 (t, J = 12.5 Hz), 2.44 (t, J = 12.1 Hz), 2.17, 2.15, 2.12, 2.10 (4 s);
13C NMR δ 144.4, 143.0, 141.7, 141.2, 136.1, 135.90, 135.87, 134.9,
133.2, 132.7, 132.3, 132.14, 132.12, 132.0, 131.4, 130.2, 129.8, 129.6,
Eluted second using CH2Cl2−hexanes (45:55) was 1.80 g (32%)
of the syn-thiacyclophane 73 as colorless crystals from cyclohexane:
1
mp 166−167 °C; H NMR δ 7.07 (br s, 3H, H-14−16), 6.96 (s, 2H,
H-5,7), 4.36 and 3.75 (AB, J = 15.1 Hz, 4H, H-1,12), 4.36 and
3.67(AB, J = 15 Hz, 4H, H-3,10), 2.56 (s, 3H, Me), 1.18 (s, 9H,
C(CH3)3); 13C NMR δ 147.4 (C-6), 142.5 (C-13,17), 135.9 (C-4,8),
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132.9 (C-15), 132.2 (C-9), 128.7 (C-14,16), 126.3 (C-5,7), 117.7
(CN), 111.7 (C-18), 35.8 (C-1,12), 34.9 (C-3,10), 34.3 (C(CH3)3),
31.2 (C(CH3)3), 17.0 (C-20); IR ν (KBr) 3040, 2962, 2214, 1592,
124.5 (C-4,10), 122.8 (C-7), 122.5 (C-1,3), 112.7 (CN), 36.6
(−C(CH3)3), 33.2 (C-10c), 32.0 (−C(CH3)3), 30.2 (C-10b), 12.0
(C-12); IR ν (thin film) 3040, 2964, 2867, 2217, 1601, 1576, 1478,
1463, 1231, 965, 878, 843, 825, 757, 736, 716 cm−1; UV−vis
(cyclohexane) λmax nm (εmax) 203 (50300), 274 (7500), 339 (43600),
377 (5600), 463 (3340), 533 (40), 575 (105), 600 (50). Attempted
mp determination converted DHP 78 into the migration product 94.
2-tert-Butyl-10a-cyano-10b-methyl-trans-10a,10b-dihydropyr-
ene (94).
1478, 1225, 1185, 871, 746 cm−1; UV (cyclohexane) λmax nm (εmax
)
292 (2320), 311 (1210); EIMS m/z 367 (M+); HRMS calcd for
C22H25NS2 367.1428, found 367.1419. Anal. Calcd: C, 71.89; H, 6.86;
N, 3.81. Found: C, 71.56; H, 6.52; N, 3.70.
For synthetic purposes, both isomers could be used together in the
next step.
1,10-Bis(methylthio)-5-tert-butyl-16-cyano-8-methyl-anti-[2,2]-
metacyclophane (75). BuLi (2.5 mmol, 1 mL, 2.5 M in hexanes) was
added dropwise to a solution of either the syn- thiacyclophane 73 or
anti-74 or a mixture of both (250 mg, 0.68 mmol) in dry THF
(30 mL) at 0 °C. The solution was allowed to warm to room
temperature over 10 min. Excess MeI (0.4 mL) was then added and
the mixture allowed to stir for another 10 min, when it was quenched
using water and then extracted with dichloromethane. The organic
extracts were dried and evaporated. The residue was chromatographed
over silica gel using CH2Cl2−hexanes (12:88) as eluent to afford 242
mg (90%) of 75 as a mixture of isomers, which could be used in the
next synthetic step. For characterization purposes, rechromatography
yielded a single isomer of 75 in which the 1,10-methylthio groups are
Cyclophanediene 77 (10 mg) was sealed in a glass tube under argon
and heated at 70 °C for 3 h (or until completely colorless), which
quantitatively converted it into colorless 94. Evaporation gave crystals:
mp 82−84 °C; 1H NMR δ 7.18 (dd, J = 7.6, 1H, H-7), 7.07−7.03 (m,
2H, H-6,8), 6.72 (d, J = 9.1, 1H, H-9), 6.50 and 6.34 (AB, J = 9.5, 1H,
H-4,5), 6.13 (s, 1H, H-3), 5.99 (d, J = 9.1 Hz, 1H, H-10), 5.53 (s, 1H,
H-1), 1.157 (s, 3H, Me), 1.153 (s, 9H, −C(CH3)3); 13C NMR δ 150.6
(C-2), 143.2 (C-3a), 136.2 (C-10c), 131.7 (C-5a), 130.9 (C-10d),
129.0 (C-5), 127.8 (C-7), 127.4 (C-6), 126.8 (C-8), 126.6 (C-4),
125.7 (C-10), 121.52 (CN), 121.48 (C-3), 113.7 (C-1), 43.2 (C-10b),
40.8 (C-10a), 34.7 (-C(CH3)3), 28.9 (-C(CH3)3), 17.4 (C-12); IR ν
(KBr) 3038, 2961, 2904, 2867, 2217, 1625, 1577, 1477, 1465, 1367,
1210, 966, 865, 825, 813, 756, 746, 661 cm−1; UV (dichloromethane)
λmax nm (εmax) 259 nm (12200), 273 (8870), 289 (4380), 301 (4520),
315 (3870), 339 (3660), 353 (3750); EIMS m/z 299 (M+) HRMS
calcd for C22H21N 299.1674, found 299.1674.
1
pseudoequatorial: mp 139−140 °C; H NMR δ 7.97 (d, J = 7.7, 2H,
H-12,14), 7.39 (t, J = 7.7, 1H, H-13), 7.28 (s, 2H, H-4,6), 4.09 (dd,
J = 11.2, 4.2 Hz, 2H, H-1,10), 2.67 (dd, J = 12.6, 4.2, 2H, H-2eq, 9eq),
2.67 (dd, J = 11.4, 12.6 Hz, 2H, H-2ax,9ax), 2.13 (s, 6H, S-Me), 1.33
(s, 9H, C(CH3)3), 0.54 (s, 3H, Me); 13C NMR δ 150.2 (C-5), 140.9
(C-8), 140.3 (C-11,15), 134.9 (C-3,7), 130.8 (C-13), 126.6 (C-12,14),
126.4 (C-4,6), 119.6 (C-16), 114.4 (CN), 54.8 (C-1,10), 42.8 (C-2,9),
34.2 (C(CH3)3, 31.3 (C(CH3)3), 15.5 (S-Me), 14.5 (C-17); IR ν
(KBr) 3049, 2951, 2864, 2216, 1598, 1479, 1455, 866, 792, 743,
578 cm−1; UV (cyclohexane) λmax nm (εmax) 274 (3040), 295 (3530);
EIMS m/z 395(M+); HRMS calcd for C24H29NS2 395.1741, found
395.1747. Anal. Calcd: C, 72.86; H, 7.39; N, 3.54. Found: C, 72.41; H,
7.02; N, 3.50.
6-tert-Butyl-9-methyl-18-phenylethynyl-2,11-dithia[3.3]-
metacyclophanes (80) and (81). A solution of bis-bromomethyl-2-
phenylethynylbenzene13 79 (3.90 g, 10.7 mmol) and 2,6 bis-mer-
captomethyl-4-tert-butyltoluene12 72 (2.57 g, 10.7 mmol) in deaerated
benzene (500 mL) was added dropwise to an ethanolic KOH solution,
prepared by adding KOH (3.4 g) to deaerated water (160 mL) and
ethanol (1470 mL) followed by addition of sodium borohydride (0.64 g).
The drop rate was very crucial, and there was a drop every 5−6 s, such
that the addition took ∼56 h. The solvent was then evaporated, and the
residue was dissolved in dichloromethane, washed with water, dried, and
evaporated. The residue was chromatographed on silica gel using
CH2Cl2-hexanes (15:85) as eluent. Eluted first was 700 mg (15%) of
Bis-sulfonium salt 76. Using the same procedure as for 33 mixed
isomers of cyclophane 75 (2.8 g, 7.0 mmol) and Borch reagent (4.5 g,
22 mmol) in dichloromethane (25 mL) gave 3.24 g (77%) of the air
sensitive bis-sulfonium salt 76: 1H NMR (DMSO-d6) δ 8.02 (d, J = 7.9
Hz), 7.91−7.85 (m), 7.75−7.62 (m), 7.49, 7.50 (singlets), 7.35−7.27
(m), 7.22−7.12 (m), 7.08 (t, J = 6.5 Hz), 6.63, 6.60 (s), 5.84−5.54
(m), 4.85−4.74 (m), 4.73−4.67 (m), 3.45−3.30 (m), 3.10−2.92 (m),
1.34−1.30 (singlets), 1.11, 1.04, 0.97, 0.69, 0.63, 0.56 (s). These were
used directly in the next step.
5-tert-Butyl-16-cyano-8-methyl-anti-[2.2]metacyclophane-1,9-
diene (77). Using the same procedure as for 12, reaction of t-BuOK
(0.87 g 7.7 mmol) and bis-sulfonium salt 76 (2.0 g, 3.35 mmol) in
THF (35 mL) followed by column chromatography using CH2Cl2−
hexanes (4:6) as eluent gave 710 mg (70%) of 77 as colorless crystals
from cyclohexane: 1H NMR δ 7.28 (t, J = 7.5 Hz, 1H, H-13), 6.85 (d,
J = 7.5 Hz, 2H, H-12,14), 6.79 (s, 2H, H-4,6), 6.62 (d, J = 11.3 Hz,
2H, H-2,9), 6.30 (d, J = 11.3 Hz, 2H, H-1,10), 1.57 (s, 3H, Me), 1.31
(s, 9H, −C(CH3)3); 13C NMR δ 154.0 (C-5), 141.5 (C-8), 141.0 (C-
11,15), 137.7 (C-2,9), 136.2 (C-3,7), 133.3 (C-13), 123.0 (C-1,10),
126.6 (C-12,14), 124.6 (C-4,6), 120.0 (C-16), 115.9 (CN), 34.5
(−C(CH3)3), 31.5 (−C(CH3)3), 19.8 (C-18); IR ν (KBr) 3048, 3009,
2964, 2904, 2867, 2215, 1571, 1476, 1443, 1217, 1154, 873, 843, 808,
1
anti 81 as colorless crystals from cyclohexane: mp 148−149 °C; H
NMR δ 7.44−7.39 (m, 2H, H-22, 26), 7.40 (d, J = 7.6 Hz, 2H,
H-14,16), 7.33−7.31 (m, 3H, H-23,24,25), 7.27 (s, 2H, H-5,7), 7.22 (t,
J = 7.6 Hz, 1H, H-15), 4.16 and 3.72 (AB, J = 14.1 Hz, 4H, H-1, 12),
3.80−3.70 (m, 4H, H-3,10), 1.42 (s, 3H, Me), 0.98 (s, 9H, −C(CH3)3.);
13C NMR δ 148.3 (C-6), 139.3 (C-13,17), 135.9 (C-9), 134.1 (C-4,8),
131.6 (C-22,26), 129.1 (C-14,16), 128.51 (C-23,25), 128.45 (C-24),
127.8 (C-15), 127.3 (C-5,7), 125.7 (C-18), 124.0 (C-21), 100.2
(C-20), 86.2 (C-19), 34.1 (-C(CH3)3), 32.4 (C-3,10), 32.1 (C-1,12),
31.1(-C(CH3)3), 15.3 (C-27); IR ν (KBr) 3057, 2959, 2904, 2862, 1594,
1477, 1488,1440, 756. 7477, 691 cm−1; UV (cyclohexane) λmax nm (εmax
)
768, 679, 660, 583, 556, 490 cm−1; UV (cyclohexane) λmax nm (εmax
)
288 (10100) 303 (11700), 318 (11900); EIMS m/z 442 (M+); HRMS
calcd for C29H30S2 442.1788, found 442.1779.
225 (31100), 287 (12440), 337 (14970), 375 (6800); EIMS m/z 299
(M+); HRMS calcd for C22H21N 299.1674, found 299.1669.
Attempted mp determination converted CPD 77 into DHP 78 and
the migration product 94.
Eluted second was 2.20 g (47%) of syn-80 as colorless crystals from
1
cyclohexane: mp 170−171 °C; H NMR δ 7.62 (dd, J = 7.8, 1.8 Hz,
2H, H-22,26), 7.40−7.44 (m, 3H, H-23,24,25), 7.02 (d, J = 7.6, 2H, H-
14,16), 7.01 (s, 2H, H-5,7), 6.86 (t, J = 7.6 Hz, 1H, H-15), 4.65 and
3.67 (AB, J = 14.8 Hz, 4H, H-1,12), 4.41 and 3.62 (AB, J = 14.8 Hz,
4H, H-3,10), 2.54 (s, 3H, Me) 1.22 (s, 9H, −C(CH3)3); 13C NMR δ
147.2 (C-6), 140.4 (C-13,17), 136.0 (C-4,8), 132.2 (C-9), 131.4
(C-22,26), 129.0 (C-15), 128.84 (C-23,25), 128.75 (C-24), 128.0
(C-14,16), 126.0 (C-5,7), 123.6 (C-21), 121.7 (C-18), 99.2 (C-20),
87.8 (C-19), 35.8 (C-1,12), 34.7 (C-3,10), 34.3 (-C(CH3)3), 31.3
2-tert-Butyl-10c-cyano-10b-methyl-trans-10b,10c-dihydropyrene
(78). Irradiation of an NMR sample of cyclophanediene 77 (10 mg) in
benzene-d6 with a UV source with output 254 nm quickly converts 77
in to 78 in ∼75% yield (∼7.5 mg) as a dark green solid: H NMR δ
8.56 (s, 2H, H-1,3), 8.44 and 8.41 (AB, J = 7.9 Hz, 4H, H-4,5,9,10),
8.30 (d, J = 7.8 Hz, 2H, H-6,8), 7.75 (t, J = 7.8 Hz, H-7), 1.49 (s, 9H,
−C(CH3)3, t-Bu), −3.97 (s, 3H, Me); 13C NMR δ 150.0 (C-2),
140.0 (C-10a,3a), 126.3 (C-5,9), 125.7 (C-5a,10d), 124.7 (C-6,8),
1
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(-C(CH3)3), 17.2 (C-27); IR ν (thin film, KBr) 3057, 2961, 2906,
2864, 1596, 1489, 1478, 1461, 1361, 1261, 872, 792, 755, 748, 691 cm−1;
UV (cyclohexane) λmax nm (εmax) 258 (16100), 297 (13600), 319
(11000); EIMS m/z 442 (M+); HRMS calcd for C29H30S2 442.1788,
found 442.1786.
(εmax) 288 nm (13500), 339 (15000), 377 (6700); EIMS 374 (M+).
Attempted mp determination converted CPD 84 into DHP 85.
2-tert-Butyl-10b-methyl-10c-phenylethynyl-trans-10b,10c-dihy-
dropyrene (85). t-BuOK (140 mg, 1.2 mmol) was added to a stirred
suspension of mixed isomers of bis-sulfonium salt 83 (350 mg,
0.52 mmol), in THF (10 mL) under argon at 20 °C. After refluxing for
6 h, water was added and then dichloromethane (90 mL). The extract
was washed, dried, and evaporated. The residue was chromatographed
over silica gel using hexanes/CH2Cl2 (85:15) as eluent to give 160 mg
(85%) of the dihydropyrene 85 as green crystals from methanol: mp
112−113 °C; 1H NMR δ 8.72 and 8.65 (AB, J = 7.8 Hz, 2H,
H-4,5,9,10), 8.69 (s, 2H, H-1,3), 8.62 (d, J = 7.8 Hz, 2H, H-6,8), 8.07
(t, J = 7.8 Hz, 1H, H-7), 6.83 (tt, J = 7.8, 1.8 Hz, 1H, H-16), 6.72 (dd,
J = 7.8, 7.5 Hz, 2H, H-15,17), 6.04 (dd, J = 7.4, 1.8 Hz, 2H, H-14,18),
1.74 (s, 9H, −C(CH3)3), −4.00 (3H, s, Me); 13C NMR δ 148.2 (C-2),
140.0 (C-3a,10a), 131.1 (C-14,18), 130.1 (C-5a,10d), 127.4 (C-15,17),
127.0 (C-16), 125.1 (C-5,9), 123.5 (C-4,10), 123.3 (C-6,8), 122.5 (C-
13), 122.0 (C-7), 121.3 (C-1,3), 84.6 (C-12) 75.4 (C-11), 36.4
(-C(CH3)3), 32.1 (-C(CH3)3), 31.2 (C-10b), 30.5 (C-10c), 12.9
(C-19); IR ν (thin film) 3036, 2963, 1597, 1489, 1478, 1442, 1230,
874, 822, 755, 737, 691, 682, 628 cm−1; UV−vis (cyclohexane) λmax
nm (εmax) 250 (41200), 339 (1.64 × 105), 377 (73200), 467 (14900),
577 (380), 639 (300); EIMS 374 (M+); HRMS calcd for C29H26
374.2034, found 374.2036.
There was no need to separate 80and 81 for synthetic purposes.
1,10-Bis(methylthio)-5-tert-butyl-8-methyl-16-phenylethynyl-
anti-[2,2]metacyclophane (82). BuLi (2.5 mmol, 1 mL, 2.5 M in
hexanes) was added dropwise to a solution of mixed thiacyclophanes
80/81 (300 mg, 0.68 mmol) in dry THF (30 mL) at 0 °C. The
solution was allowed to warm up to room temperature over 10 min
when the dark solution had turned pale yellow. Excess MeI (0.4 mL)
was added and was allowed to stir for another 10 min. The reaction
was quenched with water (5 mL) and then was extracted with
dichloromethane. The organic extracts were dried and evaporated. The
residue was chromatographed over silica gel using CH2Cl2-hexanes
(12:88) as eluent and gave 290 mg (80%) of mixed isomers of 82. For
characterization purposes, rechromatography yielded 150 mg of a
single isomer of 82 in which the 1,10 methylthio groups are pseudo-
1
equatorial: mp 203−204 °C; H NMR δ 7.86 (d, J = 7.6 Hz, 2H,
H-12,14), 7.28 (tt, J = 6.4, 1.5 Hz, 1H, H-22), 7.27−7.17 (m, 4H,
H-20,21,23,24), 7.21 (t, J = 7.6 Hz, 1H, H-13), 7.14 (s, 2H, H-4,6),
4.45 (dd, J = 11.4, 4.1 Hz, 2H, H-1ax,10ax), 3.24 (dd, J = 12.4, 4.1 Hz,
2H, H-2eq,9eq), 2.74 (dd, J = 12.2, 11.6 Hz, 2H, H-2ax,9ax), 2.18 (s, 6H,
S-Me), 0.91 (s, 9H, −C(CH3)3), 0.63 (s, 3H, Me); 13C NMR δ 148.4
(C-5), 140.0 (C-8), 138.8 (C-11,15), 135.2 (C-3,7), 131.7 (C-13),
130.2 (C-16), 128.3 (C-22), 127.3, 128.5 (C-20,21,23,24), 125.8
(C-12,14), 125.2 (C-4,6), 123.6 (C-19), 92.8 (C-18), 86.2 (C-17),
54.6 (C-1,10), 43.5 (C-2,9), 34.1 (-C(CH3)3), 31.3 (-C(CH3)3), 15.9
(C-30,31), 14.9 (C-25); IR (thin film, KBr) 3044, 2952, 2913, 1596,
1490, 1425, 754, 745, 690 cm−1; UV (cyclohexane) λmax nm (εmax) 280
(13000), 293 (13500), 320 (12600); EIMS m/z 470 (M+); HRMS
calcd for C31H34S2 470.2102, found 470.2104. Anal. Calcd: C, 79.09;
H, 7.28. Found: C, 79.35; H, 7.01
8,16-Diformyl-anti-[2.2]metacyclophane-1,9-diene (27). DIBAL
(2.5 mmol, 2.5 mL of 1 M solution in cyclohexane) was added
dropwise to a solution of dicyano CPD3 5 (250 mg, 1 mmol) in dry
dichloromethane (12 mL) at room temperature, over a period of 6 min. It
was stirred for 5 h at 20 °C, after which it was slowly added to
methanol (5 mL) and stirred for 30 min. Then HCl (10 mL, 1M) was
added carefully and the resulting solution was extracted with
dichloromethane . The organic layer was dried, evaporated, and
column chromatographed over silica using ethyl acetate:dichloro-
methane (1:9) as eluent to yield 146 mg (56%) of the diformyl-CPD
1
27 as colorless crystals from methanol: H NMR δ 9.35 (s, 2H, H-
1, 10-Bis(methylthio)-8-methyl-16-phenylethynyl-anti-[2.2]-
metacyclophane Bis-sulfonium Salt (83). Using the same procedure
as for 33, the pure 1,10-diequatorial-methylthio isomer of 83 (1.0 g,
2.1 mmol) on reaction with Borch reagent (1.0 g, 4.8 mmol) in
CH2Cl2 (7 mL) gave 1.4 g (quant.) of 83 as a single isomer: 1H NMR
(DMSO-d6) δ 7.87 (d, J = 7.8 Hz, 2H, H-12,14), 7.58 (dd J = 7.8, 2.3
Hz, 2H, H-20,24), 7.47 (t, J = 7.76 Hz, 1H, H-13), 7.41 (m, 3H,
H-21−23), 7.35 (s, 2H, H-4,6), 4.66 (dd, J = 12.0, 4.2 Hz, 2H,
H-1ax,10ax), 3.60 (dd, J = 12, 4.2 Hz, 2H, H-2eq,9eq), 3.46 (s, 6H,
S-Me2), 3.17 (triplet, J = 12 Hz, 2H, H-2ax,9ax), 3.04 (s, 6H, S-Me2),
0.89 (s, 9H, −C(CH3)3), 0.75 (s, 3H, Me). When mixed isomers were
17,18), 7.39 (t, J = 7.4 Hz, 2H, H-5,13), 6.85 (d, J = 7.4 Hz, 4H, H-
4,6,12,14), 6.73 (s, 4H, H-1,2,9,10); 13C NMR) δ 185.8 (C-17,18),
145.4(C-8,16), 140.0 (C-3,7,11,15), 135.4 (C-1,2,9,10), 135.3 (C-
5,13), 128.8 (C-4,6,12,14); IR ν (KBr) 3056, 3011, 2924, 2869, 2768,
1712, 1683, 1559, 1445, 1222, 1181, 816, 761, 628 cm−1; UV−vis
(dichloromethane), λmax nm (εmax) 245 nm (8500), 274 (8600), 338
(4150), 345 (4130), 395 sh (1500); EIMS m/z 260 (M+). Attempted
mp determination converted CPD 27 into migration product 30.
1,10a-Diformyl-trans-1,10a-dihydropyrene (30). Diformyl-CPD
27 (10 mg) in CDCl3 (1 mL) was sealed in a glass tube under argon
and heated at 70 °C for 1 h, which converted it into 30. Evaporation
gave colorless solid (10 mg, 100%) which decomposed on attempted
chromatography but was pure enough to obtain the following data: 1H
NMR δ 9.71 (d, J = 3.4 Hz, 1H, H-18), 9.34 (s, 1H, H-17), 7.69 (d, J =
8.3 Hz, 1H, H-5), 7.61 (d, J = 8.4 Hz, 1H, H-6), 7.32 (dd, J = 6.9, 8.4
Hz, 1H, H-7), 7.28 (d, J = 8.3 Hz, 1H, H-4), 7.11 (d, J = 6.8 Hz, 1H,
H-8), 6.9 (d, J = 9.6 Hz, 1H, H-9), 6.7 (d, J = 9.9 Hz, 1H, H-3), 5.91
(dd, J = 9.6, 6.2 Hz, 1H, H-2), 5.68 (d, J = 9.6 Hz, 1H, H-10), 3.76
(dd, J = 6.3, 3.5 Hz, 1H, H-1); 13C NMR δ 198.7 (C-18), 191.0(C-17),
133.5 (C-5a), 132.9 (C-9), 131.3 (C-3), 131.2 (C-3a), 130.5 (C-10d),
128.6 (C-6), 128.41 (C-10c), 128.2 (C-5), 127.1 (C-7), 126.1 (C-4),
125.6 (C-10b), 125.3 (C-8), 122.7 (C-10), 122.0 (C-2), 55.9 (C-10a),
51.1 (C-1); IR ν (thin film) 3048, 2927, 2820, 2721, 1719, 1685, 1590,
1569, 1502, 1174, 842, 770, 734 cm−1; UV−vis (dichloromethane)
λmax nm (εmax) 208 (850), 243 (13500), 274 (24600), 322 (3600), 322
(3600), 338 (4100), 402 (2130), 470 sh (460); EIMS m/z 260 (M+)
Attempted chromatography of 30 led to formation of
1-formylpyrene 31.
1
used the following NMR data was obtained: H NMR (DMSO-d6) δ
7.88−7.34 (m), 7.0−6.8 (m), 6.6 (br s), 5.83−5.55 (m), 4.8−4.6 (m),
4.04−3.00 (m), 2.26, 1.98 (s), 1.18, 0.78 (9 singlets). These were used
in the next step.
5-tert-Butyl-8-methyl-16-phenylethynyl-anti-[2.2]metacyclophane-
1,9-diene (84). Using the same procedure as for 12, reaction of bis-
sulfonium salt 83 (300 mg, 0.45 mmol) and t-BuOK (120 mg, 1.1
mmol) in THF (10 mL) followed by chromatography over silica gel in
a foil wrapped column using hexanes/CH2Cl2 (80:20) as eluent gave
147 mg (90%) of CPD 84 as colorless crystals: 1H NMR δ 7.25−7.23
(m, 5H), 7.12 (t, J = 7.4 Hz, 1H), 6.77 (d, J = 7.4 Hz, 2H), 6.58 (s,
2H), 6.49 (d, J = 11.3 Hz, 2H), 6.36 (d J = 11.3 Hz, 2H), 1.65 (s, 3H,
t‑
Me), 0.80 (s, 9H, C(CH3)3, Bu); 13C NMR δ 150.6, 141.7, 137.4,
131.3, 130.2, 129.4, 128.3, 127.8, 125.9, 124.6, 123.1, 95.1, and 90.0
(CC), 33.0 (C-26), 30.7 (-C(CH3)3) 20.2 (Me). 1H NMR (C6D6) δ
7.28 (dd, J = 7.1, 1.5 Hz, 2H, H-20,24), 6.92−6.98 (m, 3H, H-21−23),
6.86 (t, J = 7.4 Hz, 1H, H-13), 6.73 (s, 2H, H-4,6), 6.54 (d J = 7.4 Hz,
2H, H-12,14), 6.42 and 6.23 (AB, J = 11.3 Hz, 2H, H-1,2,9,10), 1.83
(s, 3H, Me), 0.93 (s, 9H, −C(CH3)3); 13C NMR (C6D6) δ 150.9
(C-5), 142.5 (C-8), 141.2 (C-11,15), 138.1 (C-3,7), 135.4 (C-2,9),
132.3 (C-20,24), 132.0 (C-1,10), 131.1 (C-16), 129.8 (C-13), 128.7
(C-21,23), 128.1 (C-22), 126.3 (C-12,14), 125.5 (C-19), 123.7
(C-4,6), 95.9 (C-18), 91.0 (C-17), 34.2 (-C(CH3)3), 31.7 (-C(CH3)3),
20.8 (C-25); IR ν (thin film) 3041, 3004, 2867, 2962, 1597, 1491,
1442, 871, 772, 757, 737, 690, 673 cm−1; UV (cyclohexane) λmax nm
ASSOCIATED CONTENT
■
S
* Supporting Information
Table S1: Thermodynamic parameters for the thermal back
reaction: cyclophanediene to dihydropyrene. UV−vis spectrum
of the orange plastic cutoff filter used for the photo-opening
677
dx.doi.org/10.1021/jo4024446 | J. Org. Chem. 2014, 79, 664−678

The Journal of Organic Chemistry
Article
(13) Cao, D.; Kolshorn, H.; Meier, H. Tetrahedron Lett. 1996, 37,
4487−4490.
experiments. General synthetic experimental conditions. The
1
numbering system used for NMR assignments. H and 13C
NMR spectra for all new compounds. Thermal closing data
with Arrhenius and Eyring plots for the thermal closing reaction
for the compounds studied. This material is available free of
charge via the Internet at http://pubs.acs.org.
AUTHOR INFORMATION
■
Corresponding Author
*Tel: 250-598-7679. Fax: 250-721-7147. E-mail: regmitch@
uvic.ca.
Present Address
‡Department of Chemistry, College of Science, King Faisal
University, Al-Ahsa 31982 Kingdom of Saudi Arabia (kayub@
kfu.edu.sa); COMSATS Institute of Information Technology,
Abbottabad, Pakistan, 22060 (khurshid@ciit.net.pk).
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
We thank the Natural Science and Engineering Research
Council of Canada and the University of Victoria for financial
support.
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