Phane properties of [2.2]paracyclophane/dehydrobenzoannulene hybrids

Article abstract of DOI:10.1002/chem.200600498

A series of [2.2]paracyclophane/dehydrobenzo[14]annulene (PC/DBA) hybrids (hydrocarbons 5, 6, 9, 10b, and 10c), [2.2]paracyclophane/dehydro[14]annulene (PC/DA) hybrids (7 and 8) and suitable model systems (11. 12. and 33) has been synthesized. Comparison

Full text of DOI:10.1002/chem.200600498

FULL PAPER
DOI: 10.1002/chem.200600498
Phane Properties of [2.2]Paracyclophane/Dehydrobenzoannulene Hybrids
Heino Hinrichs,[a] Andrew J. Boydston,[b] Peter G. Jones,[c] Kirsten Hess,[d]
[a]
Rainer Herges,[d] Michael M. Haley,*[b] andHenning Hopf*
Dedicated to Professor Siegfried Hünig on the occasion of his 85th birthday
Abstract: A series of [2.2]paracyclophane/dehydrobenzo[14]annulene (PC/DBA)
hybrids (hydrocarbons 5, 6, 9, 10b, and 10c), [2.2]paracyclophane/dehydro[14]an-
nulene (PC/DA) hybrids (7 and 8) and suitable model systems (11, 12, and 33) has
been synthesized. Comparison of the electronic absorption spectra in each series
of compounds provides further insight into the global communication between the
decks in the [2.2]paracyclophane unit.
Keywords: annulenes
reactions · cyclophanes · electronic
interactions · electronic spectra
·
coupling
Introduction
velopment of new p-electron-rich systems targeted for mate-
rials uses.
Highly conjugated organic compounds are now used in ma-
terials science for a variety of electronic and photonic appli-
cations, such as liquid crystal displays, organic LEDs, solar
cells and optical storage devices.[1] Nonetheless, the rational
design of unsaturated organic molecules with specific prop-
erties is still a challenging task. The chemical and physical
properties of a conjugated organic molecule can be control-
led by a multitude of factors, such as conjugation length,
planarity versus non-planarity, double versus triple bonds as
building units or introduction of electron donating and/or
withdrawing groups.[2] With such possible variation of struc-
tures, there is still considerable room for exploration and de-
In our opinion, the [2.2]paracyclophane unit (PC unit)
represents a particularly valuable core for studying the
effect of electronic “gaps” on the delocalization in highly
conjugated molecules. We recently reported the synthesis of
ethynylated [2.2]paracyclophanes 1, 2, and 4.[3] Together
with 3,[4] these compounds represent unique building blocks
for the construction of extended p-electron-rich hydrocar-
bons. Starting from 1 and 2, we have synthesized and com-
[a]Dr. H. Hinrichs, Prof. Dr. H. Hopf
Institut für Organische Chemie
Technische Universität Braunschweig
Hagenring 30, 38106 Braunschweig (Germany)
Fax : (+49)531-391-5388
E-mail: h.hopf@tu-bs.de
[b]A. J. Boydston, Prof. Dr. M. M. Haley
Department of Chemistry, University of Oregon
Eugene, OR 97403-1253 (USA)
Fax : (+1)541-346-0487
E-mail: haley@uoregon.edu
[c]Prof. Dr. P. G. Jones
Institut für Anorganische und Analytische Chemie
Technische Universität Braunschweig
Hagenring 30, 38106 Braunschweig (Germany)
pared the paracyclophane/dehydrobenzoannulene (PC/
DBA) systems 5 and 6 and their dehydroannulene analogues
7 and 8, respectively. Using 3 and 4, the larger hybrids
“step” 9 and “propeller” 10 were prepared. All new paracy-
clophane-containing systems (5–10) were compared with a
number of model compounds (e.g. 11 and 12) to determine
[d]K. Hess, Prof. Dr. R. Herges
Otto-Diels-Institut für Organische Chemie
Universität Kiel
Otto-Hahn-Platz 4, 24118 Kiel (Germany)
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Please note: Minor changes have been made to this manuscript since its publication in Chemistry - A European Journal Early View. The Editor.

trast to annulenes with an odd number of twists (Mçbius an-
nulenes), which are aromatic with 4n electrons. The benzo-
annelation confers remarkable kinetic stability on the highly
unsaturated dehydroannulene ring. However, the tropicity
of the annulene ring is dramatically reduced because delo-
AHCTREcUNG alization of the p electrons in the annulene ring competes
with that of the annelated benzene rings.[6] To study this
effect, alkene hybrids 7 and 8 have been synthesized and
compared with benzoannulenes 5 and 6. ACID calculations
were performed with 10a and 12a to investigate the induced
ring currents.
Results andDiscussion
Synthesis: The straightforward syntheses of PC/DBAs 5 and
6 using the building block 13a is shown in Scheme 1.
the effect of PC incorporation on the delocalization in the
overall p system.
Another type of molecule that can be used to study the
effects of p–p interactions between aromatic decks and their
effect on the delocalization in annulenes are the fascinating
acetylenic cyclophane macrocycles (e.g. 12a) synthesized by
Fallis and co-workers.[5] An X-ray study of 12a has shown a
propeller-type orientation in the solid state. The two ben-
zene rings are aligned in a slightly offset but overlapping
manner with an inter-ring distance of 3.57 Š, which is appre-
ciably greater than the typical 3.09 Š found in most [2.2]pa-
Pd-catalyzed
cross-coupling
of
4,5-diethynyl-
AHCTREUNG
[2.2]paracyclophane[3] (1) with 1-iodo-2-(trimethylsilylethy-
nyl)benzene[7] (13a) provided tetrayne 14, which was desily-
lated and cyclized using a one-pot procedure[8] to give ortho-
PC/DBA 5 in 56% overall yield. The pseudo-ortho deriva-
tive 6 was synthesized in the same manner in 67% overall
yield, starting from 4,15-diethynyl
and 13a.
Because of anticipated solubility problems, the
bis(dehydrobenzoannuleno)[2.2]paracyclophanes 9 and 10b
were synthesized with solubilizing tert-butyl substituents by
cross-coupling of the tetraethynyl
[2.2]paracyclophanes 3[4]
and 4[3] with iodobenzene 13b (formation of 16 and 17b, re-
[2.2]paracyclophane[3] (2)
ACHTREUNG
ACHTREUNGracyclophane derivatives. To study the electronic effect in
annulenic systems, we have additionally synthesized 12b and
12c, which are related to Fallisꢁ systems, and compared
them with their [2.2]paracyclophane derivatives 10b and
10c.
ACHTREUNG
AHCTREUNG
From a formal point of view, structures 10 and 12 are
doubly twisted (3608 twist of the p nodal plane) annulenes
which should be antiaromatic with 32 (4n) electrons, in con-
Scheme 1. a) 13a, [Pd
CH3CN, CH3OH; c) K2CO3, CuCl, CuAHCTRENUG
A
ACHTREUNG(OAc)2,
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ACHTREUNG[2.2]Paracyclophane/Dehydrobenzoannulene Hybrids
FULL PAPER
spectively), followed by in situ deprotection/cyclization as
described for the PC/DBAs 5 and 6. Since 10b shows strong
delocalization through the alkyne units (see below), the
donor-substituted N,N-dibutylamino derivative 10c was pre-
pared by cross-coupling of 4 with iodobenzene 13c (forma-
tion of 17c) followed by in situ deprotection/homocoupling
(Scheme 2).
Scheme 3. a) KOH, CH3OH, Et2O; b) 13b, [PdACHTREUNG
THF; c) K2CO3, CH3OH, CH2Cl2; d) [Pd
THF.
ACHTREUNG
zo[14]annulenes) (Dd=+0.48, +0.12, +0.30 for R=decyl;
Dd=+0.37, +0.02, +0.23 for R=NBu2) whereas the spec-
tra of the bis(dehydrobenzo[15]annulenes) display no signif-
icant shift differences (Dd=+0.08, +0.08, +0.15 for R=
decyl; Dd=+0.01, +0.03, +0.08 for R=NBu2).[9]
The syntheses of the non-ethano-bridged cyclophynes 12b
and c were carried out in a slightly different manner than re-
ported by Fallis for 12a.[5] Pd-catalyzed cross-coupling of io-
dobenzenes 13b or c with 1,4-diethynylbenzene (20)[11] fur-
nished the tetraynes 21b and c, which were deprotected to
the terminal alkynes 22b and c with K2CO3 in CH3OH
under standard conditions. The final dimerization to 12b
and c, respectively, was accomplished by using CuACHTRE(UNG OAc)2 in
a 3:1 mixture of pyridine/Et2O under high dilution condi-
tions (Scheme 4).
Scheme 2. a) 13b, [Pd
A
ACHTRE(UNG OAc)2,
CH3CN, CH3OH, CH2Cl2; c) 13c, [PdAHCTREUNG
The synthesis of functionalized bis(dehydrobenzoannule-
no)benzenes has recently been reported.[9] In the case of the
neutral derivative, the decyl group was chosen to increase
the solubility. Since we have used the tert-butyl group in the
PC/DBA systems, the unknown tetrakis(tert-butyl)bis(dehy-
drobenzo[14]annulene) (11) was synthesized here as a
model compound.
Treatment of 1,2,4,5-tetrakis(trimethylsilylethynyl)ben-
zene (18)[10] with KOH in methanol/Et2O provided the de-
protected tetrayne which, because of its instability, was used
directly in the following cross-coupling step to give 19 in
39% yield (Scheme 3). Deprotection of 19 was accomplish-
ed by treatment with K2CO3 in methanol/CH2Cl2. Since in-
tramolecular homocoupling under Eglinton conditions with
Cu salts/pyridine gave exclusively the bis(dehydroben-
zo[15]annulene) in 39% yield,[9c] oxidative homocoupling
Scheme 4. a) 13b or 13c, [Pd
ACTHREU(GN PPh3)4], CuI, iPr2NH, THF; b) K2CO3,
CH3OH, CH2Cl2; c) Cu(OAc)2, pyridine, Et2O.
AHCTREUNG
Even though the required iodobenzenes 13b and c have
been widely used by the Bunz group,[12] their synthesis and
characterization has not been described to date. The synthe-
sis of the neutral tert-butyl derivative 13b starts from known
triazene 23,[13] which was treated with trimethylsilylacetylene
(TMSA) in a Pd-catalyzed cross-coupling reaction. Triazene
24 was converted to the iodo compound 13b by heating in
CH3I at 1208C in a sealed ampoule.[14] To obtain iodoben-
using [PdACHTREUNG
(dppe)Cl2],[9a] a Pd complex with a cis-bidentate
ligand, was applied to give bis(dehydrobenzo[14]annulene)
11 in 75% yield.
1
The H NMR spectrum of 11 shows a downfield shift of
the annulene protons relative to precursor 19 (Dd=+0.40,
+0.16, +0.26). Comparable downfield shifts were observed
for decyl- and dibutylamino-substituted bis(dehydroben-
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H. Hopf, M. M. Haley et al.
zene 13c, N,N-dibutyl-3-iodoaniline (25)[15] was treated with
TMSA under Pd catalysis. The final iodination was per-
formed employing the mild reagent BnNMe3ICl2
(Scheme 5).[16]
X-ray structure analysis: Single crystals of 12b were pre-
pared by slow diffusion of CH3OH into a CH2Cl2 solution.
The structure of 12b is shown in Figure 1. The molecule pos-
sesses crystallographic twofold symmetry. The central rings
(C13–C18 and its symmetry equivalent) subtend a surpris-
ingly large interplanar angle of 108, with an interplanar dis-
tance of about 3.7 Š and an offset of about 0.95 Š (note
that the latter two quantities are strictly only defined for
parallel rings). Some of the angles at triply bonded atoms
deviate appreciably from linearity, notably those of 1728 at
C11 and C12. The structure of 12a[5] is more regular than
that of 12b, with parallel rings at a distance of 3.56 Š.
Compound 4 (Figure 2) displays an essentially typical
[2.2]paracyclophane geometry. The rings have a flattened
boat conformation, with the bridgehead atoms displaced by
0.16–0.17 Š from the plane of the other four atoms of the
relevant ring. The interplanar angle is 0.48 and the distance
between ring centroids (calculated without bridgehead
atoms) is 3.08 Š. The rings are mutually rotated by about
98. The packing shows one short C-H···p contact, from C2–
H2b to the centroid of C12,13,15,16: C-H 1.08, H···p 2.60 Š,
angle 1418, via the 21 operator.
Scheme 5. a) TMSA, [PdACHTER(UGN PPh3)4], CuI, iPr2NH, THF; b) CH3I, 1208C;
c) BnNMe3+ICl2À, CaCO3, CH3OH, CH2Cl2.
As mentioned above, we have also prepared PC/DA sys-
tems to study the ring currents in dehydroannulenic systems.
The ortho derivative 7, which proved to be stable only in
dilute solutions, was obtained in about 10% yield by cross-
NMR Spectroscopy: The PC/DBA and PC/DA systems, in
which the [14]annulene framework is ortho-fused to one of
the benzene decks of the [2.2]paracyclophane unit, can be
used to detect an induced ring current in the annulene core.
In these systems, the cyclophane protons 15-H/16-H lie
above the annulene ring and thus can function as an aniso-
tropy probe.
coupling of 4,5-diethynylACHTREU[NG 2.2]paracyclophane (1) with (Z)-
(4-chloro-3-buten-1-ynyl)trimethylsilane (27)[17] to tetrayne
28, followed by an in situ deprotection/homocoupling proto-
col (Scheme 6).
1
The aromatic region of the H NMR spectra of PC/DBA
5 and its precursor 14 is shown in Figure 3. Upon cycliza-
tion, 15-H and 16-H show a distinct upfield shift (Dd=
À0.37 ppm) when compared with the analogous resonances
in 14, indicative of a diatropic ring current in the [14]an-
nulene unit. The upfield shift is considerably more pro-
nounced in going from 28 to 7 (Dd=À0.92 ppm). Because
of ring current competition between annulene and benzene
rings, the cyclophane protons 7-H and 8-H experience a
slight downfield shift (Dd=0.19–0.25 ppm). These two ef-
fects cause problems in analyzing the ring currents in “step”
PC/bis-DBA 9. Even though the expected upfield shift in
going from 16 to 9 is observed (Dd=À0.24 ppm), one has to
consider that the same protons experience a downfield shift
due to a competing ring current.
The stronger aromaticity in the [14]annulene unit of 7 as
compared to 5 is corroborated by ACID (anisotropy of the
induced current density) calculations.[19] The ACID scalar
field is interpreted as the density of delocalized electrons
and is plotted (very much the same way as the total electron
density) as an isosurface (yellow “bulges” in Figure 4). Cur-
rent density vectors plotted onto the ACID isosurface indi-
cate that in 5 all benzene rings are included in the diatropic
ring current, except the benzene in the upper deck of the cy-
clophane unit. Thus, the perimeter includes 26 rather than
14 electrons (both 4n+2). However, the conjugation is re-
duced by benzoannelation. A qualitative inspection of the
Scheme 6. a) 1, [Pd
CH3OH, CH3CN; c) 2, [Pd
CH3OH, THF; e) Cu(OAc)2, CH3CN.
G
ACHTRE(UNG OAc)2,
AHCTREUNG
ACHTREUNG
Cross-coupling of 4,15-diethynylCAHTRE[UNG 2.2]paracyclophane (2)
with 27 gave tetrayne 29 in quantitative yield. Initial at-
tempts using the method described above for the annulene
formation resulted in a disappointing 16% yield. However,
stepwise deprotection with K2CO3 in CH3OH/THF followed
by Cu-catalyzed homocoupling with Cu
furnished the pseudo-ortho PC/DA 8 in 91% overall yield.
ACHTRE(UNG OAc)2 in CH3CN
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ACHTREUNG[2.2]Paracyclophane/Dehydrobenzoannulene Hybrids
FULL PAPER
(yellow) ACID isosurface in
Figure 4 already palpably dem-
onstrates the different degree
of conjugation in 5 and 7. We
use the critical isosurface values
(CIV) to quantify the strength
of conjugation. CIVs are consis-
tently higher in 7 compared
with 5 (Figure 4). The weakest
point of conjugation is the cen-
À
tral C C bond in the 1,3-diyne
unit with CIV=0.023 in 5 and
0.068 in 7. Our ACID results
thus predict a much stronger ar-
omaticity in 7 and explain the
higher upfield shift of 15-H and
16-H in 7 compared with 5.
Since one of the benzene rings
of the [2.2]cyclophane unit is
included in the perimeter of the
diatropic ring current, the pro-
tons 15-H and 16-H are close to
the ring center and therefore
are sensitive probes for “measuring” the aromaticity of the
tetrayne ring.
Figure 1. Molecular structure of 12b; ellipsoids are drawn with 50% probability.
We could not detect a distinct ring current in the periph-
ery of 6 and 8.
Electronic absorption spectra: The absorption of ultraviolet
or visible light by a molecule causes the excitation of an
electron from an initially occupied orbital with lower energy
to a previously unoccupied orbital with higher energy. De-
localization of the p electrons results in a lower energy of
the p* orbital, causing a bathochromic shift of the absorp-
tion maxima. To gain a deeper insight into the electronic
structures of the PC/DBA systems, we have compared their
UV/Vis spectra with the spectra of their silyl-protected pre-
cursors and with the model systems 30–33.
Figure 2. Molecular structure of 4; ellipsoids are drawn with 50% proba-
bility.
Figure 5 compares the electronic absorption spectra of
ortho PC/DBA 5, its precursor 14 and dehydrobenzo[14]an-
nulene (31).[20]
A
significant bathochromic shift (Dl
ꢀ60 nm) is observed relative to 14, indicating conjugation in
Figure 3. Aromatic region of the 1H NMR spectra of a) dibenzo-
ACHTREUNG[2.2]paracyclophanotetradehydro[14]annulene (5) and b) its open precur-
sor 14.
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H. Hopf, M. M. Haley et al.
question to answer was whether
9
behaves more like
a
bis[14]DBA with communica-
tion between the annulene
decks or more like two inde-
pendent [14]annulene systems.
The electronic absorption
spectra (Figure 7) show for
both systems the expected bath-
ochromic shift relative to the
silyl-protected precursor. Com-
paring 9 with bisDBA 4 gives
evidence for stronger delocali-
zation in the unbridged system
4, indicating no or only weak
p–p interactions between the
annulene decks in PC/bisDBA
9. A comparison of the elec-
tronic absorption spectra of the
[14]annulenes (Figure 8) sup-
Figure 4. ACID plot of 5 and 7 (B3LYP/6-31G* optimized geometry, isosurface value 0.03). Current density
vectors are plotted onto the isosurface (small green arrows with red arrow head, length is proportional to the
current, magnetic field is orthogonal with respect to the 14-membered ring, large green arrow). The green
arrows with red arrow head around the periphery indicate qualitatively the flow of the current. The diatropic
ring current (clockwise) in 7 is distinctively stronger than in 5. Critical isosurface values (CIV) which indicate
the degree of conjugation are given for selected bonds. The CIVs are also consistently higher in 7 compared
with 5. Both the ring current and the CIVs indicate a much stronger aromaticity of the [14]annulene unit in 7.
Figure 5. Electronic absorption spectra of 5 (g), 14 (c), and 31
(c).
Figure 6. Electronic absorption spectra of 6 (a), 15 (c), 30 (g),
and 31 (c).
the [14]annulene unit. Compared with 31, PC/DBA 5 shows
a bathochromic shift of ꢀ15 nm, which can be explained by
through-space interactions in the cyclophane moiety.
A comparison of the electronic absorption spectra of
pseudo-ortho PC/DBA 6, “open” precursor 15, model
system 30 (which contains the same chromophores as 6 but
lacks the bridging ethylene units) and dehydrobenzo[14]an-
nulene (31) is shown in Figure 6.
In the pseudo-ortho derivative 6, a significant bathochro-
mic shift (Dl ꢀ25–40 nm) is observed relative to the precur-
sor 15 and model system 30. Interestingly, 6 shows nearly
the same shift as 31 but with greater absorption intensity.
Furthermore, 6 has an extended absorption cut-off relative
to the other compounds. Both observations are most proba-
bly a result of delocalization throughout the fully conjugated
macrocycle by through-space interactions in the cyclophane
unit.
Figure 7. Electronic absorption spectra of 9 (a), 11 (c), 16 (c),
and 19 (g).
ports the previous assumption. “Step” PC/bisDBA 9 shows
nearly the same shift as PC/DBA 5, indicating that the an-
nulenes in 9 behave more like two independent [14]an-
nulene units.
To gain a deeper insight into the p–p interactions between
the cyclophane decks, “step” PC/bisDBA 9 was synthesized
and compared with flat bisDBA 11 (Figure 7). The main
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ACHTREUNG[2.2]Paracyclophane/Dehydrobenzoannulene Hybrids
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Figure 10. Electronic absorption spectra of 10b (a), 12b (c), 17b
(g), and 21b (c).
Figure 8. Electronic absorption spectra of 5 (a), 9 (c), 11 (g), and
31 (c).
The neutral propeller-type PC/DBA 10b displays the
same three band pattern as seen in hydrocarbon 6, but with
a red shift of about 20–25 nm for the first two bands and
about 55 nm for the low energy band. With the added elec-
tron density of four NBu2 groups, the bands are further red
shifted by about 35 nm for the first two bands and about
60 nm for the low energy band (Figure 9).
Figure 11. Electronic absorption spectra of 10c (a), 12c (c), 17c
(g), and 21c (c).
glance that an annulene in which the p orbitals are almost
parallel should exhibit a 3608 twist of the nodal p plane. The
twist becomes apparent if the “Figure 8-shaped” system is
transformed into a planar ring (Figure 12).
Annulenes with an even number (including 0) of 1808
twists follow the Hückel rule (aromatic with 4n+2 elec-
trons). Mçbius annulenes with an odd number of twists are
aromatic with 4n electrons.[22] The propeller annulenes 10
Figure 9. Electronic absorption spectra of 6 (g), 10b (c), and 10c
(c).
To study the effect of the distance between the cyclo-
phane decks on the delocalization in the PC/DBA, we have
compared the electronic absorption spectra of the PC/DBAs
10 with their silyl-protected precursors 17 and the non-
ethano-bridged systems 12.
For the neutral systems (Figure 10), the [2.2]paracy-
clophane derivative 10b shows a small bathochromic shift of
the low energy band by about 10 nm relative to precursor
17b. Compared with 12b, the low energy band of 12b is red
shifted by about 35 nm, the higher energy bands display a
red shift of about 8 nm. In case of the tetra-donor systems
(Figure 11), a bathochromic shift of the low energy band
(ca. 30 nm) is observed for the [2.2]paracyclophane system
10c relative to precursor 17c and non-ethano-bridged deriv-
ative 12c.
Figure 12. Transformation of number 8 shaped structure 12a to a planar
ring (keeping the mutual overlap of the p orbitals) results in a double
twist of the p system.
The propeller-type structures 10 and 12 can be viewed as
doubly twisted annulenes.[21] It seems paradoxical at a first
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H. Hopf, M. M. Haley et al.
and 12, with 32 electrons in the perimeter, should thus be
antiaromatic. To investigate the electronic and magnetic
properties, we performed ACID[19] calculations (B3LYP/6-
31G*) and plotted the current density vectors onto the
ACID isosurface of 10a and 12a (Figure 13).
Figure 14. Electronic absorption spectra of 6 (a), 15 (c), 32 (g),
and 33 (c).
A comparison of “step” PC/bisDBA with ortho-PC/DBA
and bisDBA gave no evidence for p-p-interactions between
the cyclophane decks, whereas the “propeller” type PC/
DBA systems show stronger delocalization than Fallisꢁ un-
bridged propeller type molecules.
Experimental Section
General procedure A: In a tube with screw cap, a solution of the iodoar-
ene in THF and iPr2NH was deoxygenated by bubbling argon through it.
[PdACHTRE(UNG PPh3)4], CuI and TMSA were added and the reaction mixture was
heated to 608C in the closed tube. The solvents were evaporated and the
residue purified by column chromatography.
Figure 13. ACID plot of the propeller-type annulenes 10a and 12a
(B3LYP/6-31G* optimized geometry, isosurface value 0.02). Current den-
sity vectors are plotted onto the isosurface (magnetic field parallel to the
C2 axis, pointing towards the viewer). There are strong ring currents in-
duced in the benzene rings and in the cylinder shaped acetylene units;
however, there is no distinct ring current including the total 32 p perime-
ter.
General procedure B: A solution of the iodoarene in THF and iPr2NH
was deoxygenated by bubbling Ar through it. To this solution, [Pd-
AHCTRE(UNG PPh3)4]and CuI were added. A deoxygenated solution of the terminal
acetylene in THF was added with a syringe pump at 608C. After 1 d, the
reaction mixture was concentrated in vacuo and purified by column chro-
matography.
The orientation of the magnetic field with respect to the
molecule was chosen in such a way as to induce a maximum
ring current (magnetic field parallel to the C2 axis). There is
no distinct ring current including the 32 p electron periph-
ery. Obviously, the benzene rings within the perimeter
reduce the contiguous 32 p conjugation.
General procedure C: K2CO3 (2.5–3 equiv per TMS group) was added to
a solution of the TMS protected alkyne in CH2Cl2/MeOH 1:1. After stir-
ring for 1 d at room temperature, the reaction mixture was diluted with
CH2Cl2 and washed with NH4Cl solution and water. The aqueous phase
was re-extracted with CH2Cl2 and the combined organic phases were
dried with Na2SO4 or MgSO4.
A comparison of the UV/Vis spectra of 8 with precursor
29, model compound 32 and annulene 33[17] is given in
Figure 14. For PC/DA 8 no bathochromic shift relative to
the corresponding model systems is observed. However, the
extended cut-off point (Dl ꢀ50–75 nm), together with the
greater absorption intensity at higher wavelength relative to
PC/DBA 6, indicates increased effective conjugation in 8,
because of the presence of the alkene units instead of ben-
zene rings.
General procedure D: K2CO3 and CuACHTRE(UNG OAc)2·H2O were added to a solu-
tion of the TMS-protected alkyne in MeOH/CH3CN. The mixture was
heated to reflux for 24 h, cooled, diluted with CH2Cl2 and washed with
brine. The organic phase was dried with Na2SO4 and the solvent removed
in vacuo.
General procedure E: A solution of the terminal acetylene in pyridine/
Et2O was added with a syringe pump to a solution of CuACTHER(UNG OAc)2 in pyri-
dine/Et2O at room temp. Upon completion, the mixture was diluted with
Et2O and washed with brine. The solvents were removed in vacuo, the
residue dissolved in CH2Cl2 and dried with Na2SO4.
N,N-Diethyl-N’-[4-tert-butyl-2-(trimethylsilylethynyl)phenyl]triazene
(24): Triazene 23[13] (1.44 g, 4 mmol) was subjected to general procedure
A (40 mL THF; 40 mL iPr2NH; 46 mg, 0.04 mmol [PdACTHER(UNG PPh3)4]; 15 mg,
Conclusion
0.08 mmol CuI; 0.85 mL, 6 mmol TMSA). Purification by column chro-
matography on silica gel (20% CH2Cl2 in pentane, Rf =0.3) gave 24
(1.21 g, 3.6 mmol, 91%) as a pale yellow solid. M.p. 388C; 1H NMR
We have synthesized a series of dehydrobenzoannulenes
and [2.2]paracyclophane/dehydrobenzoannulene hybrids and
compared their electronic properties in order to study the
through-space interactions in the [2.2]paracyclophane unit.
(400 MHz, CDCl3): d=0.25 (s, 9H, SiACTHER(UNG CH3)3), 1.29 (s, 9H, CACHTRENUG
(t, 3J=7.1 Hz, 6H, N(CH2CH3)2), 3.77 (q, 3J=7.1 Hz, 4H, N
ACTHERUGN ACHTREUNG
7.27 (dd, 3J5,6 =8.9, 4J5,3 =2.4 Hz, 1H, 5-H), 7.30 (d, 3J6,5 =8.9 Hz, 1H, 6-
H), 7.50 (d, 4J3,5 =2.4 Hz, 1H, 3-H); 13C NMR (100 MHz, CDCl3): d=0.1
7110
www.chemeurj.org
ꢀ 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2006, 12, 7103 – 7115

ACHTREUNG[2.2]Paracyclophane/Dehydrobenzoannulene Hybrids
FULL PAPER
(q), 11.2, 14.3 (brq), 31.3 (q), 34.3 (s), 41.9, 49.0 (brt), 97.0 (s), 104.2 (s),
116.4 (d), 117.3 (s), 126.5 (d), 129.9 (d), 147.5 (s), 150.5 (s); IR (ATR):
n˜ =2969 (m), 2961 (m), 2902 (w), 2868 (w), 2156 (m), 1485 (w), 1465 (m),
1450 (m), 1431 (w), 1416 (w), 1385 (m), 1331 (m), 1248 (m), 1204 (m),
1109 (m), 1090 (m), 927 (m), 885 (w), 831 (vs), 756 cmÀ1 (s); MS (EI):
m/z (%): 329 (11) [M +], 230 (26), 229 (100) [M +], 215 (41), 214 (20),
190 (25), 173 (24), 145 (37), 70 (76), 57 (74); elemental analysis calcd
(%) for C19H31N3Si (329.56): C 69.25, H 9.48, N 12.75, Si 8.52; found C
69.42, H 9.59, N 12.88.
action mixture was concentrated and the residue was redissolved in
CH2Cl2 and filtered through a pad of silica gel. Column chromatography
on silica gel (10% CH2Cl2 in hexanes) gave 15 (600 mg, 85%) as a bright
yellow solid. M.p. 62–638C; 1H NMR (300 MHz, CDCl3) d=2.93 (ddd,
2J=12.6, 3J=10.5, 3J=5.4 Hz, 2H), 3.12 (ddd, 2J=12.7, 3J=10.5, 3J=
2.1 Hz, 2H), 3.38 (ddd, 2J=12.7, 3J=10.5, 3J=5.4 Hz, 2H), 3.93 (ddd,
2J=12.6, 3J=10.5, 3J=2.1 Hz, 2H), 6.56–6.57 (m, 4H), 7.22 (brs, 2H),
7.27–7.30 (m, 4H), 7.54–7.57 (m, 4H); 13C NMR (75 MHz, CDCl3); d=
0.0, 33.7, 34.6, 91.8, 93.5, 98.2, 104.0, 124.9, 125.0, 126.4, 127.5, 128.2,
132.4, 132.9, 133.3, 133.4, 134.7, 139.7, 142.3; IR (neat): n˜ =3088, 3060,
3028, 3012, 2958, 2930, 2896, 2854, 2204, 2156, 1590, 1488, 1475, 1441,
1250, 862, 843, 758 cmÀ1; UV (CH2Cl2): lmax (log e)=238 (4.71), 320
(4.41), 339 nm (4.31); MS (FAB): m/z (%): 600 (25) [M +], 585 (25), 527
(65), 285 (80), 239 (100).
4-tert-Butyl-2-[(trimethylsilyl)ethynyl]iodobenzene (13b): In a pressure
tube with Teflon screw cap, a solution of 24 (3.58 g, 10.8 mmol) in freshly
distilled CH3I (19 mL) was heated for 24 h at 1208C. The reaction mix-
ture was cooled to room temperature and the solvent was removed.
Column chromatography on silica gel (20% CH2Cl2 in pentane, Rf =0.74)
gave 13b (3.81 g, 10.7 mmol, 99%) as
a
pale yellow oil. 1H NMR
(CH3)3), 7.02
PC/DBA 6: CuCl (741 mg, 7.48 mmol) and K2CO3 (1.36 g, 7.48 mmol)
were added to a solution of 15 (155 mg, 0.25 mmol) in pyridine (30 mL)
and CH3OH (30 mL). The dark blue-green slurry was stirred for 72 h.
The reaction mixture was diluted with CH2Cl2 and washed successively
with 5% HCl solution, saturated NaHCO3, and water. The organic layer
was dried (MgSO4) and filtered. Column chromatography on silica gel
(20% CH2Cl2 in hexanes) provided 6 (90 mg, 79%) as a yellow powder.
M.p. 281.28C (decomp); 1H NMR (300 MHz, CDCl3): d=2.78–2.89 (m,
2H), 3.03–3.19 (m, 4H), 3.68–3.76 (m, 2H), 6.62 (m, 4H), 7.10 (brs, 2H),
7.39–7.27 (m, 4H), 7.57–7.50 (m, 4H); 13C NMR (75 MHz, CDCl3): d=
33.3, 35.7, 78.6, 82.1, 91.0, 93.5, 123.5, 124.0, 127.8, 128.9, 129.0, 131.0,
132.4, 133.1, 133.8, 133.8, 139.8, 143,3, IR (KBr): n˜ =3060, 3024, 3004,
2958, 2925, 2886, 2849, 2215, 2196, 1581, 1552, 1482, 1442, 752 cmÀ1; UV
(CH2Cl2): lmax (log e)=231 (4.69), 293 (4.68), 312 (4.57), 340 nm (4.28);
MS (FAB): m/z (%): 455 (19) [M +], 242 (100), 136 (54).
(400 MHz, CDCl3): d=0.29 (s, 9H, Si(CH3)3), 1.28 (s, 9H, CACHTREUNG
A
(dd, 3J5,6 =8.4, 4J5,3 =2.5 Hz, 1H, 5-H), 7.49 (d, 4J3,5 =2.5 Hz, 1H, 3-H),
7.73 (d, 3J6,5 =8.4 Hz, 1H, 6-H); 13C NMR (100 MHz, CDCl3): d=À0.1
(q), 31.0 (q), 34.5 (s), 97.5 (s), 97.9 (s), 107.1 (s), 127.3 (d), 129.1 (s),
130.0 (d), 138.3 (d), 151.1 (s); IR (ATR): n˜ =2960 (m), 2901 (w), 2867
(w), 2160 (m), 1459 (m), 1382 (m), 1248 (m), 1113 (m), 1014 (m), 919
(m), 838 (vs), 817 (s), 757 (s), 706 cmÀ1 (m); MS (GC-MS): m/z (%): 356
(54) [M +], 341 (100), 229 (4), 199 (16), 149 (22); elemental analysis calcd
(%) for C15H21ISi (356.29): C 50.56, H 5.94, I 35.61, Si 7.88; found C
50.58, H 5.92.
N,N-Dibutyl-3-[(trimethylsilyl)ethynyl]aniline (26): N,N-Dibutyl-3-iodoa-
niline (25,[15] 1.69 g, 5 mmol) was subjected to general procedure A
(40 mL THF; 40 mL iPr2NH; 58 mg, 0.05 mmol [PdACTHRE(UNG PPh3)4]; 19 mg,
0.1 mmol CuI; 1.1 mL, 7.5 mmol TMSA). Purification by column chroma-
tography on silica gel (5% CH2Cl2 in pentane, Rf =0.15) gave 26 (1.4 g,
4.6 mmol, 93%) as a pale yellow oil. 1H NMR (400 MHz, CDCl3): d=
4,16-Bis(6’-trimethylsilyl-1’,5’-hexadiyne-3’-ene)CAHTRE[UNG 2.2]paracyclophane (29):
A mixture of THF (150 mL) and nPrNH2 (20 mL) was deoxygenated by
bubbling N2 through it. To this solution was added (Z)-(4-chloro-3-buten-
1-ynyl)-trimethylsilane[17] (390 mg, 2.46 mmol) [Pd
ACHTREUNG
0.29 (s, 9H, SiACHTREUNG
(CH3)3), 0.99 (t, 3J=7.4 Hz, 6H, NCH2CH2CH2CH3), 1.38
(sextet, 3J=7.4 Hz, 4H, NCH2CH2CH2CH3), 1.54–1.61 (m, 4H,
NCH2CH2CH2CH3), 3.25–3.28 (m, 4H, NCH2CH2CH2CH3), 6.62–6.64 (m,
1H, 6-H), 6.75–6.78 (m, 2H, 2-H, 4-H), 7.13 (t, 3J=7.9 Hz, 1H, 5-H);
13C NMR (100 MHz, CDCl3): d=0.0 (q), 14.0 (q), 20.3 (t), 29.3 (t), 50.6
(t), 92.3 (s), 106.5 (s), 112.4 (d), 114.9 (d), 119.1 (d), 123.5 (s), 128.9 (d),
147.9 (s); IR (ATR): n˜ =2957 (m), 2930 (m), 2898 (w), 2871 (m), 2155
(m), 1592 (m), 1566 (m), 1493 (m), 1463 (m), 1367 (m), 1288 (w), 1248
(m), 1189 (m), 1145 (m), 1108 (w), 1025 (w), 937 (w), 889 (m), 839 cmÀ1
(vs), 761 (m); MS (GC-MS): m/z (%): 301 (22) [M +], 259 (18), 258
(100), 216 (43), 202 (16), 186 (19).
AHCTREUNG
THF (5 mL) was added. The reaction vessel was wrapped in aluminium
foil and the reaction was stirred at room temperature for 24 h. The dark
green solution was diluted with Et2O and filtered through a pad of silica
gel. Radial chromatography on silica gel (10% CH2Cl2 in hexanes) pro-
vided 29 (567 mg, 97%) as a yellow solid. 1H NMR (300 MHz, CD2Cl2):
d=0.26 (s, 18H), 2.85 (ddd, 2J=12.8, 3J=10.5, 3J=6.0 Hz, 2H), 3.08
(ddd, 2J=12.8, 3J=10.5, 3J=2.0 Hz, 2H), 3.29 (ddd, 2J=12.8, 3J=10.4,
3J=6.0 Hz, 2H), 3.79 (ddd, 2J=12.8, 3J=10.4, 3J=2.0 Hz, 2H), 5.94 (d,
3J=11.0 Hz, 2H), 6.17 (d, 3J=11.0 Hz, 2H), 6.57 (brs, 4H), 7.01 (brs,
2H); 13C NMR (75 MHz, CD2Cl2): d=0.2, 33.9, 35.1, 91.2, 97.9, 103.1,
103.3, 118.8, 121.2, 124.8, 134.2, 134.3, 134.8, 140.5, 143.3; IR (neat): n˜ =
3034, 2956, 2931, 2896, 2855, 2190, 2139, 1589, 1578, 1412, 1249, 1043,
842, 760 cmÀ1; UV (CH2Cl2): lmax (log e)=230 (4.39), 258 (4.25), 329
(4.50), 349 nm (4.38); MS (FAB): m/z (%): 501 (55) [M +], 427 (95), 353
(70), 235 (100), 136 (94).
N,N-Dibutyl-4-iodo-3-[(trimethylsilyl)ethynyl]aniline (13c): N,N-Dibutyl-
3-[(trimethylsilyl)ethynyl]aniline (26, 2.81 g, 9.3 mmol) in CH2Cl2
À
(170 mL) and CH3OH (30 mL) was treated with (BnNMe3)+ICl2 (3.24 g,
9.3 mmol) and CaCO3 (1.33 g, 13.3 mmol). The reaction mixture was stir-
red for 2 h and filtered. The filtrate was washed with NaHSO3 solution
(200 mL, 5%) which was subsequently extracted with Et2O. The com-
bined organic layers were dried with Na2SO4 and concentrated in vacuo.
Chromatography on silica gel (pentane, Rf =0.27) gave 13c (2.70 g,
6.3 mmol, 68%) as a pale yellow oil. 1H NMR (400 MHz, CDCl3): d=
0.28 (s, 9H, SiACHTREUNG
(CH3)3), 0.94 (t, 3J=7.4 Hz, 6H, NCH2CH2CH2CH3), 1.33
PC/DA 8: K2CO3 (1 mL sat. solution) was added to a solution of 29
(120 mg, 0.24 mmol) in THF (20 mL) and CH3OH (20 mL). The flask
was wrapped with aluminum foil and the reaction mixture was stirred for
2 d at room temp. The mixture was diluted with Et2O, washed with
NH4Cl, brine and water and dried with MgSO4. The solution was concen-
trated and diluted with CH3CN. The flask was wrapped with aluminium
(sextet, 3J=7.4 Hz, 4H, NCH2CH2CH2CH3), 1.48–1.56 (m, 4H,
NCH2CH2CH2CH3), 3.18–3.22 (m, 4H, NCH2CH2CH2CH3), 6.32 (dd,
4
4
3J6,5 =8.9, J6,2 =3.1 Hz, 1H, 6-H), 6.75 (d, J2,6 =3.1 Hz, 1H, 2-H), 7.51 (d,
3J5,6 =8.9 Hz, 1H, 5-H); 13C NMR (100 MHz, CDCl3): d=0.0 (q), 14.0
(q), 20.3 (t), 29.2 (t), 50.6 (t), 82.5 (s), 96.8 (s), 107.6 (s), 114.3 (d), 116.0
(d), 129.4 (s), 138.7 (d), 147.8 (s); IR (ATR): n˜ =2958 (s), 2927 (s), 2871
(m), 2857 (m), 2361 (s), 1583 (s), 1482 (m), 1464 (m), 1369 (m), 1249 (m),
1028 (m), 949 (s), 844 cmÀ1 (vs); MS (GC-MS): m/z (%): 427 (45) [M +],
385 (20), 383 (100), 341 (49), 184 (42), 163 (54), 73 (18).
foil and CuCAHTRE(UNG OAc)2 (654 mg, 3.6 mmol) was added. The mixture was stir-
red at 408C for 36 h, diluted with Et2O and washed with brine and water.
The organic phase was dried with MgSO4 and purified by preparative
TLC on silica (15% CH2Cl2 in hexanes) to provide 8 (80 mg, 0.23 mmol,
94%) as a bright yellow solid. M.p. 171–1738C (decomp); 1H NMR
(300 MHz, CD2Cl2): d=2.74–2.84 (m, 2H), 2.94–3.04 (m, 2H), 3.10–3.18
(m, 2H), 3.54–3.64 (m, 2H), 5.91 (d, 3J=10.2, 2H), 6.38 (d, 3J=10.2,
2H), 6.60–6.61 (m, 4H), 6.96 (brs, 2H); 13C NMR (75 MHz, CD2Cl2): d=
33.7, 35.8, 84.6, 90.7, 98.6, 98.9, 117.8, 123.5, 126.6, 133.8, 134.1, 134.3,
140.4, 144.7; IR (neat): n˜ =3042, 2954, 2925, 2887, 2849, 2165, 1540, 1449,
1432, 905, 869, 739 cmÀ1; UV (CH2Cl2): lmax (log e)=229 (4.35), 292
4,16-Bis
(15):
878 mg, 2.93 mmol) in Et3N (30 mL) was deoxygenated by bubbling N2
through it. To this solution was added [Pd(PPh3)4](176 mg, 0.15 mmol)
and CuI (85 mg, 0.44 mmol). A deoxygenated solution of 4,16-diethynyl-
[2.2]paracyclophane[3] (2, 300 mg, 1.17 mmol) in THF (5 mL) was added
with a syringe. The reaction was stirred at 408C for 18 h. The cooled re-
A
ACHTRE[UNG 2.2]paracyclophane
A
AHCTREUNG
ACHTREUNG
Chem. Eur. J. 2006, 12, 7103 – 7115
ꢀ 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
7111

H. Hopf, M. M. Haley et al.
(4.33), 325 (4.19), 329 (4.18), 362 (3.99), 436 nm (3.42); MS (FAB): m/z
(%): 354 (23) [M +], 307 (30), 217 (60), 154 (100).
1219 (15), 1220 (8) [M +], 1217 (20), 1144 (20), 1145 (20), 1146 (13), 1072
(17), 1000 (11), 73 (100).
PC/bis-DBA 10b: Polyyne 17b (38 mg, 0.033 mmol) was subjected to
general procedure D (46 mg, 0.33 mmolK2CO3; 265 mg, 1.32 mmol Cu-
4,5,12,13-Tetrakis(4’-tert-butyl-2’-[trimethylsilyl]ethynylphenylethynyl)-
[2.2]paracyclophane[4] (3,
ACHTREUNG[2.2]paracyclophane (16): 4,5,13,14-TetraethynylACHTREUGN
AHCTREU(GN OAc)2·H2O; 66 mL CH3OH; 66 mL CH3CN; 13 mL CH2Cl2). Purifica-
15 mg, 0.05 mmol) in THF (1.5 mL) was coupled with 4-tert-butyl-2-[(tri-
methylsilyl)ethynyl]iodobenzene (13b, 89 mg, 0.25 mmol) as described in
general procedure B (14 mg, 0.013 mmol [PdACHTRE(UNG PPh3)4]; 7 mg 0.038 mmol
CuI; 6 mL THF; 7.5 mL iPr2NH). Column chromatography on silica gel
(10% CH2Cl2 in pentane, Rf =0.07) gave 16 (25 mg, 0.02 mmol, 41%) as
a colorless solid. M.p. 1388C; 1H NMR (400 MHz, CDCl3): d=0.22 (s,
tion by preparative thick layer chromatography (20% CH2Cl2 in pentane,
Rf =0.49) yielded 10b (12 mg, 0.013 mmol, 40%) as a pale yellow solid.
M.p. ꢀ2208C (decomp); 1H NMR (400 MHz, CDCl3): d=1.35 (s, 36H,
CACHTER(UNG CH3)3), 3.06–3.14 (m, 4H, 1-, 2-, 9-, 10-H), 3.48–3.56 (m, 4H, 1-, 2-, 9-,
10-H), 7.18 (s, 4H, 5-, 8-, 12-, 15-H), 7.40 (dd, 3J5’,6’ =8.2, 4J5’,3’ =2.0 Hz,
4H, 5’-H), 7.48 (d, 3J6’,5’ =8.2 Hz, 4H, 6’-H), 7.55 (d, 4J3’,5’ =2.0 Hz, 4H,
36H, SiACHTREUNG(CH3)3), 1.34 (s, 36H, CCAHTRE(UGN CH3)3), 3.15–3.22 (m, 4H, 1-, 2-, 9-, 10-
3’-H); 13C NMR (100 MHz, CDCl3): d=31.0 (q, C
ACHTREUNG
H), 3.71–3.78 (m, 4H, 1-, 2-, 9-, 10-H), 7.08 (s, 4H, 7-, 8-, 15-, 16-H), 7.30
3
(dd, 3J5’,6’ =8.2, 4J5’,3’ =2.1 Hz, 4H, 5’-H), 7.55 (d, J6’,5’ =8.2 Hz, 4H, 6’-H),
-2, -9, -10), 34.9 (s, CACHTREUNG
4
7.56 (d, J3’,5’ =2.1 Hz, 4H, 3’-H); 13C NMR (100 MHz, CDCl3): d=0.1 (q,
C-7’), 92.9 (s, C-7’ or C-8’), 123.9 (s, C-2’), 124.4 (s, C-4, -7, -13, -16),
125.7 (s, C-1’), 126.4 (d, C-5’), 128.1 (d, C-3’), 132.1 (d, C-6’), 133.8 (d, C-
5, -8,
-12, -15), 143.1 (s, C-3, -6, -11, -14), 151.6 (s, C-4’); IR (ATR): n˜ =2959
(s), 2926 (m), 2902 (m), 2867 (m), 1594 (w), 1494 (s), 1462 (m), 1427 (m),
1394 (m), 1363 (m), 1255 (m), 1200 (m), 1127 (m), 1027 (m), 900 (m), 828
(s), 738 (m), 725 (m), 712 cmÀ1 (m); UV (CH2Cl2): lmax (lg e)=232 (5.11),
258 (4.82), 290 (4.8), 312 (5.15), 338 (4.95), 366 (4.67), 394 nm (4.78); MS
(MALDI-TOF): m/z: 947.3, 948.4, 949.4 [M ++Na], 924.3, 925.4, 926.4
[M +].
SiACHTREUNG(CH3)3), 31.1 (q, CACHTREUNG(CH3)3), 33.0 (t, C-1, -2, -9, -10), 34.8 (s, CACHTREU(NG CH3)3),
92.1 (s, C-8’), 95.9 (s, C-7’), 97.5 (s, C-10’), 104.5 (s, C-9’), 123.5 (s, C-1’),
124.6 (s, C-2’), 125.7 (d, C-5’), 128.2 (s, C-4, -5, -12, -13), 129.9 (d, C-3’),
130.2 (d, C-7, -8, -15, -16), 132.7 (d, C-6’), 142.4 (s, C-3, -6, -11, -14), 151.1
(s, C-4’); IR (ATR): n˜ =2961 (m), 2904 (w), 2869 (w), 2155 (w), 1494 (m),
1462 (m), 1393 (m), 1363 (w), 1248 (m), 1200 (w), 1126 (w), 1094 (w), 925
(m), 837 (vs), 757 (s), 700 cmÀ1 (m); UV (CH2Cl2): lmax (lg e)=240
(5.00), 251 (5.00), 310 (4.78), 343 nm (4.64); MS (ESI, Ag+): m/z (%):
1324 (63), 1325 (69), 1326 (100), 1327 (84), 1328 (52), 1329 (25), 1330
(10).
4,7,13,16-Tetrakis(4’-N,N-dibutylamino-2’-[trimethylsilyl]ethynylphenyl-
ethynyl)CAHTRE[UGN 2.2]paracyclophane (17c): 4,7,13,16-tetraethynyl[2.2]paracyclo-
phane (4, 26 mg, 0.085 mmol) in THF (1 mL) was coupled with N,N-dibu-
tyl-4-iodo-3-[(trimethylsilyl)ethynyl]aniline (13c, 172 mg, 0.425 mmol) as
PC/bis-DBA 9: A solution of polyyne 16 (12 mg, 0.01 mmol) in CH2Cl2
(10 mL) was subjected to general procedure D (14 mg, 0.1 mmolK2CO3,
80 mg, 0.4 mmol CuACHTREUNG(OAc)2·H2O, 20 mL CH3OH, 20 mL CH3CN).
Column chromatography on silica gel (20% CH2Cl2 in pentane) yielded
described in general procedure B (8 mg, 0.007 mmol [PdACHTRE(UGN PPh3)4]; 1 mg,
0.007 mmol CuI; 5 mL THF; 6 mL iPr2NH). Purification by preparative
thick layer chromatography (20% CH2Cl2 in pentane, Rf =0.22) yielded
17c (50 mg, 0.033 mmol, 39%) as a yellow solid. M.p. 888C; 1H NMR
9 (5 mg, 0.005 mmol, 50%) as a colorless solid. M.p. ꢀ1808C (decomp);
1H NMR (400 MHz, CDCl3): d=1.41 (s, 36H, C
ACHTRE(UNG CH3)3), 3.21–3.49 (m,
4H, 1-, 2-, 9-, 10-H), 3.88–3.95 (m, 4H, 1-, 2-, 9-, 10-H), 6.84 (s, 4H, 7-,
8-, 15-, 16-H), 7.60 (dd, 3J5’,6’ =8.3, 4J5’,3’ =2.0 Hz, 4H, 5’-H), 7.69 (d,
4J3’,5’ =2.0 Hz, 4H, 3’-H), 7.89 (d, 3J6’,5’ =8.3 Hz, 4H, 6’-H); 13C NMR
(100 MHz, CDCl3): d=31.2 (q, CACTHREU(NG CH3)3), 33.7 (t, C-1, C-2, C-9, C-10),
35.0 (s,
(400 MHz, CDCl3): d=0.22 (s, 36H, Si
ACHTREUNG
24H, NCH2CH2CH2CH3), 1.37 (ps-sextet,
NCH2CH2CH2CH3), 1.55–1.62 (m, 16H, NCH2CH2CH2CH3), 3.07–3.13
(m, 4H, 1-H, 2-H, 9-H, 10-H), 3.29 (t, J=7.5 Hz, 16H,
3
NCH2CH2CH2CH3), 3.62–3.70 (m, 4H, 1-, 2-, 9-, 10-H), 6.59 (dd, J5’,6’
=
CACHTREUNG(CH3)3), 80.2 (s, C-10’), 86.5 (s, C-9’), 93.2 (s, C-8’), 97.3 (s, C-7’), 122.4
8.8, 4J5’,3’ =2.6 Hz, 4H, 5’-H), 6.75 (d, 4J3’,5’ =2.6 Hz, 4H, 3’-H), 7.15 (s,
(s, C-2’), 125.3 (s, C-4, -5, -12, -13), 126.2 (d, C-3’), 126.3 (d, C-5’), 127.3
(s, C-1’), 130.0 (d, C-7, -8, -15, -16), 132.6 (d, C-6’), 143.9 (s, C-3, -6, -11,
-13), 151.4 (s, C-4’); IR (ATR): n˜ =3281 (br), 2959 (s), 2927 (s), 2867 (m),
2167 (w), 1694 (m), 1596 (m), 1558 (m), 1484 (s), 1460 (m), 1436 (m),
1394 (w), 1363 (m), 1254 (m), 1198 (m), 1167 (m), 1129 (m), 1100 (m),
1027 (w), 903 (m), 866 (m), 823 (s), 796 (w), 730 cmÀ1 (vs); UV (CH2Cl2):
lmax (lg e)=230 (4.80), 315 (4.91), 326 (4.97), 345 (4.65), 355 (4.56),
368 nm (4.50); MS (ESI, Ag+): m/z (%): 1031 (78), 1032 (63), 1033 (100),
1034 (65), 1035 (24).
4H, 5-, 8-, 12-, 15-H), 7.42 (d, 3J6’,5’ =8.8 Hz, 4H, 6’-H); 13C NMR
(100 MHz, CDCl3): d=0.1 (q, SiCAHTRE(UNG CH3)3), 14.0 (q, NCH2CH2CH2CH3),
20.3 (t, NCH2CH2CH2CH3), 29.4 (t, NCH2CH2CH2CH3), 32.8 (t, C-1, C-2,
C-9, C-10), 50.6 (t, NCH2CH2CH2CH3), 91.1 (s, C-8’), 93.9 (s, C-7’), 96.6
(s, C-10’), 105.0 (s, C-9’), 112.2 (d, C-5’), 113.1 (s, C-1’), 115.1 (d, C-3’),
125.3 (s, C-4, -7, -13, -16), 125.9 (s, C-2’), 133.6 (d, C-6’), 134.4 (d, C-5, -8,
-12, -15), 141.4 (s, C-3, -6, -11, -14), 147.3 (s, C-4’); IR (ATR): n˜ =2956
(m), 2929 (m), 2868 (m), 2193 (w), 2151 (w), 1593 (vs), 1535 (m), 1506
(s), 1463 (w), 1363 (m), 1294 (w), 1246 (m), 1224 (m), 1180 (m), 1096 (s),
939 (w), 906 (w), 836 (vs), 804 (s), 755 (m), 722 cmÀ1 (m); UV (CH2Cl2):
lmax (lg e)=246 (4.99), 262 (4.92), 358 (4.74), 422 nm (5.00); MS (EI):
m/z (%): 1500 (18), 1501 (25), 1502 (20), 1503 (13), 1504 (7) [M +], 1427
(6), 1428 (7), 1429 (5), 1277 (8), 1278 (8), 1279 (6), 73 (100).
4,7,13,16-Tetrakis(4’-tert-butyl-2’-[trimethylsilyl]ethynyl-phenylethynyl)-
[2.2]paracyclophane[3]
ACHTREUNG[2.2]paracyclophane (17b): 4,7,13,16-TetraethynylACHTREUGN
(4, 61 mg, 0.2 mmol) in THF (2 mL) was coupled with 4-tert-butyl-2-[(tri-
methylsilyl)ethynyl]iodobenzene (13b, 257 mg, 1.0 mmol) as described in
general procedure B (18 mg, 0.016 mmol [PdACHTRE(UNG PPh3)4]; 3 mg 0.016 mmol
PC/bis-DBA 10c: Polyyne 17c (38 mg, 0.025 mmol) was subjected to gen-
CuI; 10 mL THF; 12 mL iPr2NH). Purification by preparative thick layer
chromatography (10% CH2Cl2 in pentane, Rf =0.07) gave 17b (40 mg,
0.03 mmol, 15%) as a pale yellow solid. M.p. 968C; 1H NMR (400 MHz,
eral procedure
D (35 mg, 0.25 mmolK2CO3; 200 mg, 1 mmol Cu-
AHCTREU(GN OAc)2·H2O; 50 mL CH3OH; 50 mL CH3CN; 10 mL CH2Cl2). Purifica-
tion by preparative thick layer chromatography (20% CH2Cl2 in pentane,
Rf =0.6) yielded 10c (20 mg, 0.017 mmol, 66%) as a yellow solid. M.p.
ꢀ1858C (decomp); 1H NMR (400 MHz, CDCl3): d=0.98 (ps-t, 3J=
7.4 Hz, 24H, NCH2CH2CH2CH3), 1.36 (ps-sextet, J=7.4 Hz, 16H,
NCH2CH2CH2CH3), 1.54–1.70 (m, 16H, NCH2CH2CH2CH3), 3.05–3.16
(m, 4H, 1-, 2-, 9-, 10-H), 3.27–3.30 (m, 16H, NCH2CH2CH2CH3), 3.43–
CDCl3): d=0.22 (s, 36H, SiACHTREUN(G CH3)3), 1.35 (s, 36H, CACHRTE(UGN CH3)3), 3.11–3.18 (m,
4H, 1-, 2-, 9-, 10-H), 3.67–3.74 (m, 4H, 1-, 2-, 9-, 10-H), 7.22 (s, 4H, 5-,
8-, 12-, 15-H), 7.33 (dd, 3J5’,6’ =8.2, 4J5’,3’ =2.0 Hz, 4H, 5’-H), 7.51 (d,
3J6’,5’ =8.2 Hz, 4H, 6’-H), 7.55 (d, 4J3’,5’ =2.0 Hz, 4H, 3’-H); 13C NMR
(100 MHz, CDCl3): d=0.07 (q, Si
ACHTRU(NEG CH3)3), 31.1 (q, CACHTRE(UGN CH3)3), 32.7 (t, C-1,
4
3.48 (m, 4H, 1-, 2-, 9-, 10-H), 6.61 (dd, 3J5’,6’ =8.8 Hz, J5’,3’ not resolved,
-2, -9, -10), 34.8 (s, C(CH3)3), 92.6 (s, C-8’), 93.3 (s, C-7’), 97.6 (s, C-10’),
ACHTREUNG
4
104.3 (s, C-9’), 123.5 (s, C-1’), 124.8 (s, C-2’), 125.4 (s, C-4, C-7, C-13, C-
16), 125.7 (d, C-5’), 129.7 (d, C-3’), 132.2 (d, C-6’), 135.0 (d, C-5, -8, -12,
-15), 141.9 (s, C-3, -6, -11, -14), 151.1 (s, C-4’); IR (ATR): n˜ =2958 (m),
2921 (m), 2900 (m), 2864 (m), 2153 (w), 2135 (w), 1587 (w), 1540 (w),
1498 (m), 1463 (m), 1431 (m), 1392 (m)1292 (w), 1247 (m), 1199 (w),
1102 (w), 926 (m), 856 (w), 832 (vs), 830 (vs), 810 (m), 757 (m), 722 cmÀ1
(m); UV (CH2Cl2): lmax (lg e)=240 (5.25), 250 (5.21), 268 (5.09), 312
(4.76), 332 (4.88), 374 (5.03), 386 nm (5.01); MS (EI): m/z (%): 1218 (22),
4H, 5’-H), 6.72 (d, J3’,5’ not resolved, 4H, 3’-H), 7.14 (s, 4H, 5-, 8-, 12-,
15-H), 7.35 (d, 3J6’,5’ =8.8 Hz, 4H, 6’-H); 13C NMR (100 MHz, CDCl3):
d=14.0 (q, NCH2CH2CH2CH3), 20.3 (t, NCH2CH2CH2CH3), 29.4 (t,
NCH2CH2CH2CH3), 33.1 (t, C-1, -2, -9, -10), 50.8 (t, NCH2CH2CH2CH3),
77.2 (s, C-10’), 82.7 (s, C-9’), 91.1 (s, C-8’), 93.6 (s, C-7’), 112.5 (d, C-5’),
113.3 (s, C-3’), 115.0 (d, C-1’), 124.4 (s, C-4, -7, -13, -16), 125.1 (s, C-2’),
133.4 (d, C-5, -8, -12, -15), 133.6 (d, C-6’), 142.5 (s, C-3, -6, -11, -14), 147.4
(s, C-4’); IR (ATR): n˜ =2955 (m), 2928 (m), 2871 (m), 2187 (w), 1593
7112
www.chemeurj.org
ꢀ 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2006, 12, 7103 – 7115

ACHTREUNG[2.2]Paracyclophane/Dehydrobenzoannulene Hybrids
FULL PAPER
(vs), 1533 (m), 1504 (s), 1462 (m), 1366 (m), 1252 (w), 1217 (m), 1182
(w), 1110 (w), 1093 (m), 906 (w), 843 (w), 806 (m), 713 cmÀ1 (w); UV
(CH2Cl2): lmax (lg e)=232 (4.93), 292 (4.76), 330 (4.97), 346 (5.00), 366
(4.82), 452 nm (4.80); MS (MALDI-TOF): m/z: 1209.6, 1208.7, 1209.6,
1210.7, 1211.7, 1212.7, 1213.7.
was coupled with 4-tert-butyl-2-[(trimethylsilyl)ethynyl]iodo-benzene
(13b, 843 mg, 2.5 mmol) in THF (5 mL) and iPr2NH (7 mL) as described
in general procedure B (46 mg, 0.04 mmol [PdCAHTRE(UNG PPh3)4]; 7 mg, 0.04 mmol
CuI). Column chromatography on silica gel (5% dichloromethane in
pentane, Rf =0.07) gave 21b (329 mg, 0.56 mmol, 56%) as a colorless
solid. M.p. 1908C (decomp); 1H NMR (400 MHz, CDCl3): d=0.21 (s,
1,2,4,5-Tetrakis(4’-tert-butyl-2’-[trimethylsilyl]ethynyl-phenylethynyl)ben-
zene (19): KOH (500 mg, 9.0 mmol) was added to a solution of 1,2,4,5-
Tetrakis[(trimethylsilyl)ethynyl]benzene[10] (18, 464 mg, 1.0 mmol) in
Et2O (10 mL) and CH3OH (17 mL). The mixture was stirred overnight,
acidified with 1n HCl and extracted with Et2O. The organic phase was
dried with Na2SO4. The solution of 1,2,4,5-tetraethynylbenzene was con-
centrated to ca. 10 mL and subjected to general procedure B (178 mg;
3
4
18H, SiACTHRE(UGN CH3)3), 1.24 (s, 18H, CHCARTEU(GN CH3)3), 7.25 (dd, J5’,6’ =8.2, J5’,3’ =2.0 Hz,
2H, 5’-H), 7.36 (d, 3J6’,5’ =8.2 Hz, 2H, 6’-H), 7.45 (d, 4J3’,5’ =2.0 Hz, 2H,
3’-H), 7.45 (s, 4H, 2-, 3-, 5-, 6-H); 13C NMR (100 MHz, CDCl3): d=0.1
(q, SiCATHER(UNG CH3)3), 31.0 (q, CAHCTRE(UGN CH3)3), 34.8 (s, CACHTREU(GN CH3)3), 90.3 (s, C-7’), 92.5 (s,
C-8’), 97.9 (s, C-10’), 104.0 (s, C-9’), 123.0 (s, C-1’), 123.3 (s, C-1, -4), 125.3
(s, C-2’), 125.7 (d, C-5’), 129.3 (d, C-3’), 131.4 (d, C-6’), 131.5 (d, C-2, -3,
-5, -6), 151.5 (s, C-4’); IR (ATR): n˜ =2956 (m), 2900 (w), 2867 (w), 2158
(m), 1512 (m), 1479 (w), 1462 (w), 1396 (m), 1363 (w), 1243 (m), 1204
(w), 1087 (w), 927 (m), 897 (w), 835 (vs), 756 cmÀ1 (s); UV (CH2Cl2): lmax
(lg e)=255 (4.49), 263 (4.63), 291 (4.16), 342 (4.63), 364 nm (4.47); MS
(EI): m/z (%): 582 (100), 583 (54), 584 (19) [M +], 567 (18), 276 (19), 221
(15), 145 (25), 73 (26); elemental analysis calcd (%) for C40H46Si2
(582.95): C 82.41, H 7.95, Si 9.64; found C 82.13, H 8.09.
5 mmol 13b; 90 mg, 0.08 mmol [PdCATHRE(UNG PPh3)4]; 15 mg, 0.08 mmol CuI;
50 mL THF; 60 mL iPr2NH). After stirring at 508C for 2 d, the solvents
were evaporated and the residue purified by column chromatography on
silica gel (10% CH2Cl2 in pentane) to give 19 (427 mg, 0.39 mmol, 39%)
as
a
light yellow solid. M.p. 2508C (decomp); 1H NMR (400 MHz,
3
CDCl3) d=0.21 (s, 36H, Si
(CH3)3), 1.32 (s, 36H, (CH3)3), 7.30 (dd, J5’,6’
=
8.3, 4J5’,3’ =2.0 Hz, 4H, 5’-H), 7.48 (d, 3J6’,5’ =8.3 Hz, 4H, 6’-H), 7.52 (d,
4J3’,5’ =2.0 Hz, 4H, 3’-H), 7.80 (s, 2H, 3-H, 6-H); 13C NMR (100 MHz,
1,4-Bis(4’-tert-butyl-2’-ethynylphenylethynyl)benzene (22b): TMS pro-
tected polyyne 21b (145 mg,0.25 mmol) in CH2Cl2 (7.5 mL) and CH3OH
(7.5 mL) was subjected to general procedure C (276 mg, 2 mmolK2CO3).
The solvents were removed in vacuo and the residue dried in high
vacuum to yield 22b (101 mg, 0.23 mmol, 92%) as a colorless solid. M.p.
1688C (decomp); 1H NMR (400 MHz, CDCl3): d=1.32 (s, 18H,
ꢁ
CDCl3) d=0.0 (q, Si
A
CACHTRE(UGN CH3)3), 34.8 (s,
CACHTREUNG(CH3)3), 90.6 (s, C-8’), 94.1 (s, C-7’), 98.2 (s, C-10’), 103.9 (s, C-9’), 123.1
(s, C-1’), 125.3 (s, C-1, -2, -4, -5), 125.4 (s, C-2’), 125.6 (d, C-5’), 129.2 (d,
C-3’), 132.0 (d, C-6’), 135.6 (d, C-3, -6), 151.5 (s, C-4’); IR (ATR): n˜ =
2962 (m), 2903 (w), 2870 (w), 2156 (w), 1507 (m), 1464 (w), 1394 (w),
1363 (w), 1248 (m), 1203 (w), 1124 (w), 1087 (w), 930 (m), 895 (w), 834
(vs), 758 cmÀ1 (s); UV (CH2Cl2): lmax (lg e)=228 (4.99), 232 (4.99), 237
(4.99), 268 (4.94), 333 (4.98), 364 (4.91), 385 nm (4.69); MS (EI): m/z
(%): 1086 (38), 1087 (40), 1088 (25), 1089 (11), 1090 (6) [M +], 1012 (16),
1013 (36), 1014 (42), 1015 (28), 1016 (12), 73 (100).
(CH3)3), 3.35 (s, 2H, C C-H), 7.36 (dd, 3J5’,6’ =8.3, 4J5’,3’ =2.0 Hz, 2H,
CACHTREUNG
5’-H), 7.47 (d, 3J6’,5’ =8.3 Hz, 2H, 6’-H), 7.52 (s, 4H, 2-, 3-, 5-, 6-H), 7.56
(d, 4J3’,5’ =2.0 Hz, 2H, 3’-H); 13C NMR (100 MHz, CDCl3): d=31.0 (q,
CCH3), 34.8 (s, CCH3), 80.5 (d, C-10), 82.7 (s, C-9), 89.9 (s, C-7), 92.6 (s,
C-8), 123.2 (s, C-1’ or C-1, -4), 123.3 (s, C-1, -4 or C-1’), 124.3 (s, C-2’),
126.0 (d, C-5’), 129.7 (d, C-3’), 131.6 (C-6’), 131.6 (d, C-2, -3, -5, -6), 151.6
(s, C-4’); IR (ATR): n˜ =3274 (s), 3061 (w), 3039 (w), 2955 (m), 2899 (m),
2861 (m), 2111 (w), 2109 (w), 1908 (w), 1783 (w), 1507 (m), 1472 (m),
1397 (m), 1361 (m), 1261 (m), 1188 (m), 1123 (w), 1098 (w), 897 (s), 828
(s), 741 cmÀ1 (m); UV (CH2Cl2): lmax (lg e)=286 (4.47), 318 (4.06), 330
(4.52), 338 (4.61), 338 (4.7), 360 nm (4.52); MS (EI): m/z (%): 440 (7),
439 (34), 438 (100) [M +], 425 (4), 424 (18), 423 (52); elemental analysis
calcd (%) for C34H30 (438.61): C 93.11, H 6.89; found C 93.05, H 6.91.
1,2,4,5-Tetrakis(4’-tert-butyl-2’-ethynyl-phenylethynyl)benzene: TMS pro-
tected polyyne 19 (136 mg, 0.13 mmol) in CH2Cl2 (4 mL) and CH3OH
(4 mL) was subjected to general procedure C (180 mg, 1.3 mmolK2CO3).
The solvents were removed in vacuo and the residue dried in high
vacuum to yield a pale yellow solid (96 mg, 0.12 mmol, 96%). M.p. 918C;
3
1H NMR (300 MHz, CDCl3) d=1.32 (s, 36H, (CH3)3), 7.36 (dd, J5’,6’
=
8.3, 4J5’,3’ =1.9 Hz, 4H, 5’-H), 7.54 (d, 3J6’,5’ =8.3 Hz, 4H, 6’-H), 7.57 (d,
4J3’,5’ =1.9 Hz, 4H, 3’-H), 7.83 (s, 2H, 3-H, 6-H); 13C NMR (75 MHz,
CDCl3) d=31.0 (q), 34.8 (s), 80.9 (d), 82.5 (s), 90.8 (s), 93.8 (s), 123.1 (s),
124.3 (s), 125.1 (s), 125.9 (d), 129.6 (d), 132.2 (d), 136.1 (d), 151.8 (s); IR
(ATR): n˜ =3286 (m), 2960 (m), 2903 (m), 2867 (m), 2112 (w), 1504 (m),
1463 (m), 1394 (m), 1362 (m), 1263 (m), 1189 (m), 1125 (m), 896 (m), 830
(s), 739 cmÀ1 (w); UV (CH2Cl2): lmax (lg e)=231 (4.91), 261 (4.75), 331
(4.96), 364 nm (4.68); MS (ESI): m/z (%): 821 (100), 822 (65), 823 (22)
[M ++Na].
tert-Butyl-annulene 12b: Polyyne 22b (329 mg, 0.75 mmol) in pyridine/
Et2O (90 mL/30 mL) was dimerized as described in general procedure E
(900 mg, 4.5 mmol CuACHTERU(NG OAc)2·H2O; 190 mL pyridine; 65 mL Et2O).
Column chromatography on silica gel (20% dichloromethane in pentane)
gave 12b (25 mg, 0.03 mmol, 8%) as a colorless solid. M.p. 1708C
(decomp). Single crystals suitable for X-ray structure analysis were ob-
tained by slow diffusion of methanol into a dichloromethane solution of
1
12b. H NMR (400 MHz, CDCl3): d=1.34 (s, 36H, C
A
tert-Butyl-bis[14]annulene (11):
A solution of [PdACHRTE(UNG dppe)Cl2](6 mg,
2-, 3-, 5-, 6-, 8-, 9-, 11-, 12-H), 7.38 (dd, 3J5’,6’ =8.3, 4J5’,3’ =1.9 Hz, 4H, 5’-
H), 7.44 (d, 3J6’,5’ =8.3 Hz, 4H, 6’-H), 7.59 (d, 4J3’,5’ =1.9 Hz, 4H, 3’-H);
13C NMR (100 MHz, CDCl3): d=31.0 (q, CCH3), 34.8 (s, CCH3), 77.5 (s,
C-10’), 81.6 (s, C-9’), 89.3 (s, C-7’), 93.9 (s, C-8’), 122.6 (s, C-1, -4, -7, -10),
124.6 (s, C-2’), 124.6 (s, C-1’), 126.4 (d, C-5’), 129.3 (d,
C-3’), 131.1 (d, C-6’), 131.5 (d, C-2, -3, -5, -6, -8, -9, -11, -12), 151.5 (s, C-
4’); IR (ATR): n˜ =2957 (m), 2926 (m), 2901 (m), 2866 (m), 2215 (w),
1909 (w), 1594 (w), 1512 (m), 1460 (m), 1393 (m), 1363 (m), 1254 (m),
2101 (m), 1126 (m), 1099 (m), 1018 (m), 891 (m), 828 (vs), 736 cmÀ1 (m);
UV (CH2Cl2): lmax (lg e)=304 (5.05), 330 (4.96), 360 nm (4.73); MS
(MALDI-TOF): m/z: 872.3, 873.3, 874.3 [M +].
0.01 mmol), CuI (3 mg, 0.015 mmol) and I2 (13 mg, 0.05 mmol) in THF
(100 mL) and iPr2NH (100 mL) was heated to 608C. To this solution was
added a solution of 1,2,4,5-tetrakis(4’-tert-butyl-2’-ethynylphenylethynyl)-
benzene (80 mg, 0.1 mmol) in THF (50 mL) with a syringe pump over
1 d. Heating was continued for 1 d, the solvents were evaporated and the
residue filtered through a pad of silica gel (50% CH2Cl2 in pentane).
Treatment of a CH2Cl2 solution with pentane (5 equiv) gave 11 (60 mg,
0.075 mmol, 75%) as a yellow solid. M.p. ꢀ2608C (decomp); 1H NMR
4
(300 MHz, CDCl3) d=1.37 (s, 36H, (CH3)3), 7.55 (dd, 3J5’,6’ =8.3, J5’,3’
=
4
3
1.9 Hz, 4H, 5’-H), 7.63 (d, J3’,5’ =1.9 Hz, 4H, 3’-H), 7.92 (d, J6’,5’ =8.3 Hz,
4H, 6’-H), 8.45 (s, 2H, 3-, 6-H); 13C NMR (100 MHz, CDCl3) d=31.1 (q,
CACHTREUNG(CH3)3), 35.0 (s, CACHTREUNG(CH3)3), 79.8 (s, C-10’), 86.0 (s, C-9’), 92.3 (s, C-8’),
1,4-Bis(4’-N,N-dibutylamino-2’-[trimethylsilyl]ethynylphenylethynyl)ben-
zene (21c): 1,4-Diethynylbenzene (20, 189 mg, 1.5 mmol) in THF
(1.5 mL) was coupled with N,N-dibutyl-4-iodo-3-[(trimethylsilyl)-ethyn-
95.1 (s, C-7’), 122.6 (s, C-1, -2, -4, -5), 122.7 (s, C-2’), 126.4 (s, d, d, C-1’,
-3’, -5’), 133.0 (d, C-6’), 143.1 (d, C-3, -6), 151.9 (s, C-4’); IR (ATR): n˜ =
2961 (vs), 2904 (m), 2868 (m), 2114 (w), 2176 (w), 1596 (m), 1506 (vs),
1485 (vs), 1468 (s), 1427 (m), 1395 (m), 1364 (s), 1256 (s), 1200 (m), 1128
(m), 1100 (m), 1024 (m), 925 (vs), 890 (vs), 737 cmÀ1 (m); UV (CH2Cl2):
lmax (lg e)=230 (5.09), 297 (5.06), 342 (5.32), 356 (5.29), 371 (5.01), 389
(4.99), 400 (4.76), 419 nm (4.22); MS (ESI, Ag+): m/z (%): 901 (82), 902
(53), 903 (100), 904 (57), 905 (8) [M ++Ag].
AHCTREUNG
AHCTREUNG
5.5 mL iPr2NH). Column chromatography on silica gel (20% CH2Cl2
pentane, Rf =0.1) gave 21c (428 mg, 0.59 mmol, 39%) as a yellow solid.
M.p. 140–1448C; 1H NMR (400 MHz, CDCl3): d=0.29 (s, 18H, Si-
AHCTREUNG
(CH3)3), 0.94 (ps-t, 3J=7.4 Hz, 12H, NCH2CH2CH2CH3), 1.32 (ps-sextet,
1,4-Bis(4’-tert-butyl-2’-[trimethylsilyl]ethynylphenylethynyl)benzene
(21b): 1,4-Diethynylbenzene[11] (20, 126 mg, 1.0 mmol) in THF (2 mL)
3J=7.4 Hz, 8H, NCH2CH2CH2CH3), 1.52 (ps-q, 3J=7.5 Hz, 8H,
NCH2CH2CH2CH3), 3.22 (ps-t, 3J=7.6 Hz, 8H, NCH2CH2CH2CH3), 6.52
Chem. Eur. J. 2006, 12, 7103 – 7115
ꢀ 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
7113

H. Hopf, M. M. Haley et al.
4
(dd, 3J5’,6’ =8.9, 4J5’,3’ =2.7 Hz, 2H, 5’-H), 6.71 (d, J3’,5’ =2.7 Hz, 2H, 3’-H),
in hexanes) provided 32 (50 mg, 92%) as a yellow solid. M.p. 77–808C;
1H NMR (300 MHz, CD2Cl2): d=6.02 (d, J=10.5, 2H), 6.25 (d, J=10.5,
2H), 7.29–7.37 (m, 6H), 7.47–7.50 (m, 4H); 13C NMR (75 MHz, CD2Cl2):
d=81.5, 82.4, 87.4, 99.5, 118.3, 123.0, 123.7, 129.0, 129.5, 132.4; IR (neat):
n˜ =3079, 3141, 2968, 2925, 2852, 2200, 2174, 2121, 1597, 1576, 1554, 1488,
1442, 1389, 1069, 1032, 916, 755, 742 cmÀ1; UV (CH2Cl2): lmax (log e)=
230 (4.40), 266 (4.21), 294 (4.31), 306 (4.35), 319 (4.31), 348 (4.35),
369 nm (4.34); MS (FAB): m/z: 302 (100) [M +], 154 (78), 136 (88).
7.31 (d, 3J6’,5’ =8.9 Hz, 2H, 6’-H), 7.47 (s, 4H, 2-, 3-, 5-, 6-H); 13C NMR
(100 MHz, CDCl3): d=0.1 (q, SiCAHTRE(UNG CH3)3), 13.9 (q, NCH2CH2CH2CH3),
20.2 (t, NCH2CH2CH2CH3), 29.3 (t, NCH2CH2CH2CH3), 50.4 (t,
NCH2CH2CH2CH3), 90.8 (s, C-8’), 91.3 (s, C-7’), 96.6 (s, C-10’), 104.7 (s,
C-9’), 111.8 (s, C-1’), 111.9 (d, C-5’), 114.6 (d, C-3’), 123.2 (s, C-1, C-4),
126.4 (s, C-2’), 130.9 (d, C-2, -3, -5, -6), 132.7 (d, C-6’), 147.5 (s, C-4’); IR
(ATR): n˜ =2956 (m), 2929 (m), 2894 (m), 2872 (m), 2857 (m), 2204 (m),
2152 (m), 1593 (vs), 1534 (m), 1515 (s), 1493 (m), 1463 (m), 1427 (m),
1399 (m), 1386 (m), 1295 (m), 1247 (m), 1221 (m), 1182 (m), 1097 (s),
940 (w), 905 (w), 833 (vs), 803 (s), 753 cmÀ1 (m); UV (CH2Cl2): lmax (lg
e)=258 (4.56), 266 (4.57), 300 (4.05), 360 (4.48), 402 nm (4.67); MS (EI):
m/z (%): 724 (100), 725 (24) [M +], 681 (20), 639 (16), 319 (14), 277 (15),
73 (10) [SiMe3+]; elemental analysis calcd (%) for C48H64N2Si2 (725.22):
C 79.50, H 8.90, N 3.86, Si 7.74; found C 79.17, H 9.13, N 3.86.
X-ray structure determinations: Numerical details are presented in
Table 1.
Table 1. Details of X-ray structure analyses of 4 and 12b.
Compound
4
12b
1,4-Bis(4’-N,N-dibutylamino-2’-ethynyl-phenylethynyl)benzene
TMS-protected polyyne 21c (181 mg, 0.25 mmol) was subjected to gener-
al procedure (276 mg, 2 mmolK2CO3; 7.5 mL CH2Cl2; 7.5 mL
(22c):
formula
Mr
habit
C24H16
304.37
colorless tablet
C68H56
873.13
pale brown prism
C
CH3OH). The solvents were removed in vacuo and the residue was dried
in high vacuum to yield 21c (132 mg, 0.23 mmol, 91%) as a yellow solid.
M.p. 1288C; 1H NMR (400 MHz, CDCl3): d=0.94 (ps-t, J=7.3 Hz, 12H,
NCH2CH2CH2CH3), 1.33 (sextet, J=7.5 Hz, 8H, NCH2CH2CH2CH3),
1.50–1.57 (m, 8H, NCH2CH2CH2CH3), 3.24 (t, J=7.6 Hz, 8H,
crystal size [mm]0.2”0.2”0.13
0.45”0.3”0.3
crystal system
space group
cell constants
a [Š]13.7087(16)
b [Š]9.4745(12)
c [Š]12.7205(16)
a [8]90
orthorhombic
Pna21
monoclinic
C2/c
24.185(3)
14.024(2)
16.621(2)
3
4
NCH2CH2CH2CH3), 3.28 (s, 2H, 10-H), 6.55 (dd, J5’,6’ =8.9, J5’,3’ =2.7 Hz,
4H, 5’-H), 6.74 (d, 4J3’,5’ =2.7 Hz, 4H, 3’-H), 7.32 (d, 3J6’,5’ =8.9 Hz, 4H,
6’-H), 7.45 (s, 4H, 2-, 3-, 5-, 6-H); 13C NMR (100 MHz, CDCl3): d=13.9
(q, NCH2CH2CH2CH3), 20.2 (t, NCH2CH2CH2CH3), 29.3 (t,
NCH2CH2CH2CH3), 50.6 (t, NCH2CH2CH2CH3), 79.5 (d, C-10’), 83.3 (s,
C-9’), 90.9 (s, C-7’, C-8’), 111.9 (s, C-1’), 112.2 (d, C-5’), 115.0 (d, C-3),
132.2 (s, C-4, C-5), 125.4 (s, C-2’), 131.1 (d, C-2, -3, -5, -6), 132.9 (d, C-6’),
147.6 (s, C-4’); IR (ATR): n˜ =3292 (m), 2957 (m), 2928 (m), 2873 (m),
2859 (m), 2201 (m), 2107 (w), 1593 (vs), 1534 (m), 1516 (s), 1463 (m),
1425 (w), 1399 (m), 1369 (s), 1292 (m), 1257 (m), 1221 (m), 1179 (m),
1091 (s), 1015 (w), 941 (w), 880 (w), 836 (vs), 807 (vs), 746 cmÀ1 (w); UV
(CH2Cl2): lmax (lg e)=241 (4.58), 249 (4.56), 298 (4.17), 359 (4.58), 397
(4.8), 406 nm (4.78); MS (EI): m/z (%): 580 (100), 581 (45) [M +], 539
(12), 537 (36), 495 (23), 395 (17), 247 (17), 226 (14), 205 (19), 198 (12), 86
(27); elemental analysis calcd (%) for C42H48N2 (580.85): C 86.85, H 8.33,
N 4.82; found C 86.45, H 8.37, N 4.57.
90
b [8]90
g [8]90
111.143(5)
90
5258.1
V [Š3]1652.2
Z
4
4
1 [MgmÀ3]1.224
1.103
0.06
m [mmÀ1]0.07
F
A
640
À140
60
1856
À140
60
T [8C]
2qmax
no. reflections
measured
independent
Rint
18176
2524
0.030
233
0.092
0.033
1.06
29739
7679
0.080
313
0.151
0.051
1.02
parameters
Tetrakis-N,N-dibutylaminoannulene 12c: Polyyne 22c (153, 0.26 mmol)
in pyridine/Et2O (38 mL/12 mL) was dimerized as described in general
procedure E (312 mg, 1.56 mmol CuCATHRE(UNG OAc)2·H2O; 95 mL pyridine; 30 mL
Et2O). Preparative thick layer chromatography on ALOX (20% Et2O in
pentane Rf =0.33) gave 12c (23 mg, 0.02 mmol, 15%) as a yellow solid
(m.p. 248–2508C). 1H NMR (400 MHz, CDCl3): d=0.94 (ps-t, J=7.3 Hz,
wR(F2, all refl.)
R
S
ACHTRE(UGN F, >4s(F))
max. D1 [eŠÀ3]0.27
0.31
12H,
NCH2CH2CH2CH3),
1.33
(sextet,
J=7.5 Hz,
8H,
NCH2CH2CH2CH3), 1.50–1.57 (m, 8H, NCH2CH2CH2CH3), 3.24 (t, J=
7.6 Hz, 8H, NCH2CH2CH2CH3), 6.52 (dd, 3J5’,6’ =8.9, 4J5’,3’ =2.7 Hz, 4H,
5’-H), 6.70 (d, 4J3’,5’ =2.7 Hz, 4H, 3’-H), 7.15 (s, 4H, 2-, 3-, 5-, 6-, 8-, 9-,
11-, 12-H), 7.24 (d, 3J6’,5’ =8.9 Hz, 4H, 6’-H); 13C NMR (100 MHz,
CDCl3): d=14.0 (q, NCH2CH2CH2CH3), 20.3 (t, NCH2CH2CH2CH3),
29.4 (t, NCH2CH2CH2CH3), 50.8 (t, NCH2CH2CH2CH3), 76.8 (s, C-10’),
81.9 (s, C-9’), 89.9 (s, C-7’), 92.2 (s, C-8’), 113.7 (s, C-1’), 112.5 (d, C-5’),
114.5 (d, C-3’), 122.6 (s, C-1, C-4, C-7, C-10), 125.7 (s, C-2’), 131.0 (d, C-2,
-3, -5, -6, -8, -9, -11, -12), 132.4 (d, C-6’), 147.4 (s, C-4’); IR (ATR): n˜ =
3078 (m), 3044 (s), 2853 (m), 2208 (w), 1718 (m), 1591 (vs), 1535 (m),
1515 (s), 1493 (m), 1458 (m), 1397 (w), 1364 (s), 1279 (m), 1254 (m), 1216
(s), 1183 (w), 1124 (m), 1092 (s), 1016 (w), 926 (w), 832 (m), 804 (m),
725 cmÀ1 (m); UV (CH2Cl2): lmax (lg e)=234 (4.75), 304 (4.67), 324
(4.73), 344 (4.75), 368 (4.74), 420 nm (4.54); MS (MALDI-TOF): m/z:
1156.7, 1157.7, 1158.7, 1159.7 [M +].
Data collection: Crystals were mounted in inert oil on glass fibres and
transferred to the cold gas stream of the diffractometer (Bruker SMART
1000 CCDC). Measurements were performed with monochromated MoKa
radiation.
Structure refinement: The structures were refined anisotropically against
F2 (program SHELXL-97, G. M. Sheldrick, University of Gçttingen). H
atoms were included using a riding model.
Special features and exceptions: For compound 13, which crystallizes in a
non-centrosymmetric space group, Friedel opposite reflections were
merged because of the lack of significant anomalous scattering. Its acety-
À
lenic hydrogens were refined freely but with C H bond lengths restrain-
ed to be equal.
CCDC-603577 (4), -603576 (12b) contain the supplementary crystallo-
graphic data for this paper. These data can be obtained free of charge
from The Cambridge Crystallographic Data Centre via www.ccdc.cam.
ac.uk/data_request/cif.
1,12-Diphenyldodeca-3,9-dien-1,5,7,11-tetrayne (32): Cu
ACHTRE(UGN OAc)2 (1.96 g,
10.8 mmol), CuCl (1.07 g, 10.8 mmol), and K2CO3 (1.49 g, 10.8 mmol)
were added to
a solution of 1-phenyl-6-(trimethylsilyl)hexa-3-en-1,5-
diyne[24] (80 mg, 0.36 mmol) in pyridine (18 mL) and CH3OH (18 mL).
The dark blue-green reaction mixture was stirred overnight at 508C. The
cooled slurry was diluted with Et2O, washed with 10% HCl solution,
dried (MgSO4), and filtered. Chromatography on silica gel (10% CH2Cl2
7114
www.chemeurj.org
ꢀ 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2006, 12, 7103 – 7115

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Received: April 7, 2006
Published online: August 7, 2006
Chem. Eur. J. 2006, 12, 7103 – 7115
ꢀ 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
7115