Suzuki-Miyaura cross-coupling reaction on copper-trans-A2B corroles with excellent functional group tolerance

Article abstract of DOI:10.1016/j.tet.2011.04.024

The palladium-catalyzed Suzuki-Miyaura cross-coupling reaction has been investigated on meso-substituted trans-A₂B-corrole using tailored Pd-catalyst systems. We present the first examples of Suzuki-Miyaura cross-coupling reactions on meso-subs

Full text of DOI:10.1016/j.tet.2011.04.024

Tetrahedron 67 (2011) 4243e4252
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SuzukieMiyaura cross-coupling reaction on copper-trans-A2B corroles with
excellent functional group tolerance
a
a
a
a
b
€
€
€
Michael Konig , Lorenz Michael Reith , Uwe Monkowius , Gunther Knor , Klaus Bretterbauer ,
Wolfgang Schoefberger a
,
*
a Institute of Inorganic Chemistry, Johannes Kepler University Linz (JKU), Altenberger Stra
b
e 69, A-4040 Linz, Austria
b Institute of Chemical Technology of Organic Substances, Johannes Kepler University Linz (JKU) Altenberger Stra
b
e 69, A-4040 Linz, Austria
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 7 March 2011
Received in revised form 29 March 2011
Accepted 7 April 2011
Available online 14 April 2011
The palladium-catalyzed SuzukieMiyaura cross-coupling reaction has been investigated on meso-
substituted trans-A2B-corrole using tailored Pd-catalyst systems.
We present the first examples of SuzukieMiyaura cross-coupling reactions on meso-substituted trans-
A2B-corrole derivatives with neutral, sterically hindered, inactivated and heteroaromatic boronic acids
and esters, alkenylboronic acids, as well as quickly deboronating aryl boronic acids and benzo-
condensated five membered heterocyclic boronic acids. In addition, we established a high-yield pro-
cedure for the SuzukieMiyaura cross-coupling reaction of corroles with neutral boronic acids.
Due to the lability of the free-base corrole macrocycles, functionalization of the corrole periphery was
performed with the corresponding Cu-metallated species. meso-Substituted trans-A2B-corrole can hence
be regarded as highly versatile platform towards more sophisticated corrole systems.
X-ray structure analysis of a functionalized meso-substituted trans-A2B copper corrole exhibited the
typical features of such a Cu-complex: short NeCu distances and a saddled corrole configuration.
Moreover, we observed a sensitivity of the formal oxidation state of the coordinated copper ions towards
SuzukieMiyaura cross-coupling reaction conditions, where the central copper(III) ion approaches the
characteristic features of a copper(II) species. This redox behaviour was examined by UV/vis absorption
spectra, nuclear magnetic resonance (NMR) experiments and time-dependent density functional theo-
retical calculations.
Keywords:
Corrole
Copper
SuzukieMiyaura coupling reaction
Pd-catalysts
Boronic acids/esters
Density functional theory (DFT)
Time-dependent DFT
Ó 2011 Elsevier Ltd. All rights reserved.
1. Introduction
metallated (Cu, Mn) corroles have also been reported,15,16,18 but
were limited to meso-pyrimidyl substituted corroles and simple
The demand of synthesizing novel symmetric and asymmetric
corroles increased significantly over the past decade. This trend was
triggered by the first published one-pot synthesis of corroles
reported in 1999 by Gross and Paolesse.1e4 Since then, the scope of
corrole application grew tremendously including examples in the
fields of catalysis, photochemical sensors, molecular electronics
and biomedicinal applications.5 For these purposes the availability
of more sophisticated corrole systems is of great interest, which
resulted in various contributions on corrole functionalization, in-
boronic acids. Thus, the ability to couple more complex boronic
acids with the corrole precursors is of prime importance and would
open up a synthetic pathway towards highly functionalized cor-
roles for the already mentioned applications.
In this work, we present the first examples of SuzukieMiyaura
cross-coupling reactions on meso-triaryl corroles with hetero-
aromatic boronic acids and esters, alkenylboronic acids, as well as
a highly efficient method for the SuzukieMiyaura of corroles with
simpler boronic acids.
cluding reactions on the
b-pyrrolic positions like bromination,
hydroformylation, nitration and chlorosulfonation as well as
cycloadditions.6e14 Reported functionalizations on the meso-sub-
stituents include SNAr-reactions15,16 and BuchwaldeHartwig type
Pd-catalyzed aminations.17 Pd-catalyzed CeC cross-coupling re-
actions (SuzukieMiyaura and LiebeskindeSrogl) carried out on
2. Results and discussion
2.1. Synthesis of the A2B-corrole scaffold and metallation
10-(4-Bromophenyl-)5,15-bis-(pentafluorophenyl)corrole 3, which
was previously synthesized in ionic liquids,19 was chosen as our basic
starting material, since derivatives with pentafluorophenyl-
substituents exhibit superior stability than most other compounds
* Corresponding author. Tel.: þ43 732 2468 8811; e-mail address: wolf-
gang.schoefberger@jku.at (W. Schoefberger).
0040-4020/$ e see front matter Ó 2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2011.04.024

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M. Konig et al. / Tetrahedron 67 (2011) 4243e4252
4244
with aromatic meso-substituents studied to date. The first step in the
synthesis of 3 (Scheme 1) was the HCl-catalyzed condensation of
pyrrole with pentafluorobenzaldehyde in water/MeOH to give the
5-pentafluorophenyldipyrromethane 2 in 85% yield.20
Numerous new catalyst systems for Suzuki cross-coupling re-
actions were reported over the last decade, including NHC-(nitrogen
heterocyclic carbene) based Pd-containing systems,22 Ni-complex
based systems23e25 and new classes of phosphine ligand based
catalysts.26,27 Due totheir commercial availabilityand easy handling
we opted for the latter. First attempts with the conditions optimized
by Buchwald et al.26, employing SPhos (2-dicyclohexylphosphino-
20,60-dimethoxybiphenyldScheme 3) asligand, Pd2(0)dba3 as
Pd-containing species (dba¼dibenzylideneacetone) and solid K3PO4
as base in the absence of water were immediately successful: we
were able to couple Cu(III) [(10-(4-BrPh)-5,15-bis-F5PhC)] 4, with
phenylboronic acid, 6a, p-tolylboronic acid, 6b, 2-naphthylboronic
acid, 6c and E-2-phenylvinylboronic acid, 6d (Table 1, Scheme 4)
with yields up to 84%, whereby no significant formation of side-
products was observed.
Scheme 3. Phosphane-ligands used in the SuzukieMiyaura reactions.
At 80 ꢀC, relatively low reaction times were necessary for full
conversion of the reactant. As the reaction with neutral and acti-
vated aryl boronic acids proved to be more or less unproblematic,
we tried to apply the same procedure on unactivated aryl- and
heteroaryl boronic acids.
Scheme 1. Synthesis of 10-(4-bromophenyl-)-5,15-bis-(pentafluorophenyl-) corrole 3.
The SuzukieMiyaura with 2-dimethylaminopyrimidine-5-bo-
ronic acid pinacol ester 6e carried out in toluene/water 10:1 ap-
plying the same catalyst system was also successful with 35% yield,
although higher reaction times (24 h) were necessary. The reaction
of 6-(1-piperazinyl)pyridine-3-boronic acid 6f went much slower
than with the boronic acids used in the previous experiments. After
24 h of a significant amount of a green open-chain side product has
formed and could be observed in addition to the non-converted
This step is followed by the condensation of 2 with 4-bromo-
benzaldehyde in water/MeOH/HCl for 1 h and subsequent oxidation
reaction with DDQ,21 which yields up to 40% of 3.
The copper-metallation (Scheme 2) was carried out in THF with
a threefold excess of Cu(II)acetate and showed almost complete
conversion of meso-phenyl substituted A2B-corrole 3 to the Cu(III)-
10-(4-bromophenyl-)-5,15-bis-(pentafluorophenyl-)corrole, Cu(III)
[(10-(4-BrPh)-5,15-bis-F5PhC)] 4.16
Table 1
Functionalization of Cu-A2B-corroles via SuzukieMiyaura reaction using Pd2(dba)3
and SPhosa
Scheme 2. Cu-metallation of 10-(4-bromophenyl-)-5,15-bis-(pentafluorophenyl-)
corrole 4.
Entry Boron derivative Solvent
Temp [ꢀC] Time [h] Product Yield [%]
2.2. Suzuki reaction on corroles
1
2
3
4
5
6
6a
6b
6c
6d
6e
6k
Toluene
Toluene
Toluene
Toluene
80
80
80
80
1
5
2
5
24
24
7a
7b
7c
7d
7e
7k
78
84
84
80
35
14
Suzuki reaction on corroles was reported earlier,15,16 but was
limited to Cu-metallated meso-pyrimidylcorroles. In doubt of the
applicability of the classic catalyst system (Pd(OAc)2/PPh3 or
Pd(0)(PPh3)4, in aqueous medium) on both meso-triphenylcorrole
derivatives and heterocyclic boronic acids, we searched for a more
versatile catalyst system, capable of coupling a large variety of
boron derivatives with the corrole system.
Toluene/H2Ob 80
Toluene/H2Ob 80
a
Reaction conditions: 1 equiv of 4, 2 equiv of boron derivative, 3 equiv of K3PO4
cat. 10 mol % Pd2(dba)3 SPhos/Pd¼2:1.
b
Toluene/H2O 10:1.

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4245
Table 2
FunctionalizationofCu-A2B-corrolesviaSuzukieMiyaurareactionusingPrecatalyst5a
Entry Boron derivative Solvent
Temp [ꢀC] Time [h] Product Yield [%]
1
2
3
4
5
6
7
8
6e
6f
6g
6h
6i
6j
6k
6l
THF/H2Ob 45
THF/H2Ob 45
THF/H2Ob 45
THF/H2Ob 45
THF/H2Ob 45
THF/H2Ob 45
THF/H2Ob 45
THF/H2Ob 45
24
24
24
24
24
24
24
24
7e
7f
7g
7h
7i
7j
7k
7l
68
84
72
82
79
d
23
45
a
Reaction conditions: 1 equiv of 4, 3 equiv of boronic acid/ester derivative,
3 equiv of K3PO4, 10 mol % of 5.
b
THF/H2O 5:3.
The cyclometallated complex 5 generates the catalytically active
XPhosPd(0) species quickly under mild conditions under, which the
deboronation of the boronic acid derivatives is significantly slowed
down, thereby allowing the coupling of less stable boronic acids.
Along with the change of the catalyst system, also the reaction
conditions were optimized: the solvent was changed from toluene
or toluene/water 10:1 (for boronic acid esters) to THF/water 5:3,
and the excess of the boron derivative was increased (from two- to
threefold). These alterations induced a significant change in the
electronic structure of the copper corrole system: upon the addi-
tion of the solvent mixture and the base, the formal oxidation state
of the central Cu ion seems to change from copper(III) to copper(II),
which was indicated by a conspicuous colour change from
brownish-red to green in solution. This finding is supported by UV/
vis and NMR experiments, which will be discussed further below.
Scheme 4. Boronic acids and boronic acid esters used in the Suzuki couplings with 4.
reactant and the product. Extending the reaction time to 48 h did
just lead to further decomposition of the reactant as well as the
product. Furthermore, the reaction with 3-nitrophenylboronic acid,
6i, 2,4,6-triisopropylphenylboronic acid dimethyl ester, 6j, and
3-(1-phenylsulfonyl-) indolebronic acid, 6g, showed absolutely no
conversion even after 48 h, when using the SPhos/Pd2(dba)3 cata-
lyst system. Only the coupling of p-amino-phenyl boronic acid
pinacol ester 6k with 4 was achieved, however in very low yields of
14% of 7k. These results showed the demand of a more efficient
catalyst system, which could enable the SuzukieMiyaura reaction
of the corrole system at significantly lower reaction temperatures.
Buchwald et al. recently presented a novel catalyst system 5
(Scheme 5), which is capable of reacting aryl bromides fast and
efficient with free boronic acids (reaction scheme, Table 2) at room
temperature or 40 ꢀC and in short reaction times of 30 min to 2 h.27
Precatalyst 5 is easily obtained in a one-pot procedure by com-
bining Pd(OAc)2 with 2-aminobiphenyl, followed by addition of LiCl
and the phosphine ligand (XPhos, Scheme 3). We obtained the first
crystal structure of the precatalyst 5. The crystallographic data are
summarized in Table S1 (Supplementary data) and the structure is
shown in Fig. 1. The crystal structure is published in the Cambridge
Crystallographic Data Center with the CCDC number: 813705.
Fig. 1. Molecular structure of 5 (ORTEP displacement ellipsoids at the 50% probability
ꢀ
level, H atoms and i-Pr substituents are omitted for clarity). Selected bond lengths [A]
and angles [ꢀ]: Pd1eC1 2.022 (4), Pd1eP1 2.270 (1), Pd1eCl1 2.428 (1), Pd1eN1 2.119
(3), C1ePd1eN1 82.9 (1), C1ePd1eP1 98.6 (1), Cl1ePd1eN1 86.1 (1), Cl1ePd1eP1
91.62 (3).
Scheme 5. Synthesis of precatalyst 5.

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Applying the improved catalyst system as well as the altered re-
action conditions, the heterocyclic boronic acids and boronic acid
pinacolesters 6eeh could be efficiently coupled with the corrole 4
within 24 h at 45 ꢀC (Table 2).
More precisely, the SuzukieMiyaura reaction with 2-dimethyl-
amino-pyrimidyl-5-boronic acid pinacol ester, 6e, 6-(piperazin-1-yl)
pyridine-3-boronic acid pinacol ester, 6f,1-(phenylsulfonyl)indole-3-
boronic acid, 6g, 2-benzofuranboronic acid, 6h gave product yields of
7eeh higher than 70% (Table 2) though product 7f was not perma-
nently stable. Its degradation was observed immediately after a sec-
ond column chromatographic purification step. Nevertheless, mass
spectrometry and UV/vis absorption spectroscopy indicated the for-
mation of the expected compound.
Furthermore, the increased Cu(II) character of the central metal
ion is observed in reaction products 7aed indicated by a more in-
tense electronic transition at 433 nm in the UV/vis spectra (Fig. 3A)
and an increased line-width in the 1H NMR experiments. In com-
pound 4, the diamagnetic Cu(III) oxidation state is stabilized,
whereas aromatic moieties in 7aee shift the equilibrium more or
less towards the Cu(II) species (indicated by an increasing shoulder
at 433 nm). Fig. 3B shows the ESR-spectrum observed for 7a in
dichloromethane at 298 K. The ESR spectrum of compound 7a ex-
hibits unsymmetrical four lines at g¼2.077 with hyperfine splitting
due to the Cu nucleus (I¼3/2). In the Supplementary data (Fig. 52)
we have additionally attached ESR spectrum of 7a in dichloro-
methane solution at 1.5 K.
In contrast to the failed coupling attempts with 6iek described
above, the SuzukieMiyaura reaction of Cu(III) [(10-(4-BrPh)-5,15-
bis-F5PhC)], 4, with 3-nitrophenylboronic acid 6i, and p-amino-
phenyl boronic acid pinacol ester 6k now gave overall yields of
about 79% and 23%, respectively. A possible side reaction in case of
6k is the BuchwaldeHartwig reaction of the amino-group with 4
via an NeC-coupling reaction.28e30 The SuzukieMiyaura reaction
of 4 with 2-benzo[b]thiopheneboronic acid 6l under described
conditions exhibited an average yield of 45% of product 7l.
2.4. Density functional theory (DFT) and time-dependent DFT
(TD-DFT) calculations
Geometry optimization of Cu(III) [(10 (4-BrPh) 5,15 bisF5PhC)]
7a indeed also results in a saddled-shape distorted structure
(Fig. 4B) and the obtained molecular structure is almost identical to
the crystal structure of 7a depicted in Fig. 4A.
The similarity of both crystal structure and calculated structure
appears when opposing the NeCueN angles of both structures.
Experimentally observed angles are 82.0ꢀ, 91.6ꢀ, 91.0ꢀ and 97.3ꢀ
for the compound 7a and match closely to the calculated ones 81.8ꢀ,
91.5ꢀ, 91.2ꢀ and 97.0ꢀ. Consequently, also the corresponding CueN-
distances match pretty well. (Experiment: Cu1eN1 1.876, Cu1eN2
2.3. Cu(III) corrole versus Cu(II) corrole species
In the absence of other ligands, the formal oxidation state of
copper corroles corresponds to a diamagnetic Cu3þ (d8) center,
bound to a trianionic corrolate macrocycle. In practice, the presence
of polar covalent bonds and the possibility of back-bonding be-
ꢀ
ꢀ
1.880, Cu1eN3 1.892, Cu1eN4 1.891, calculations: 1.881 A, 1881 A,
ꢀ
ꢀ
1.903 A, 1.904 A). Furthermore, the enhanced saddling distortion of
tween the corrolate
p-electron system and the (formally empty) Cu
the corrole backbone in 7a, measured as the mean angle between
3dx2ꢁy2 orbital gives rise to a much smaller effective charge at the
copper center. Such an electron donation may be accomplished by
two alternative interaction types: (a) a dative bond from the cor-
rolate nitrogen lone pairs to the Cuþ3 ion, providing a more co-
planes (c)ofoppositepyrroleringsareexperimentallydetermined to
be
c
¼15.4ꢀ and
c
¼17.3ꢀ. The corresponding calculated
c-angles are
15.1ꢀ and 17.1ꢀ.
The conformation of the corrole ligand however rearranges from
the saddle-shape structure to a more relaxed geometry when ap-
plying the geometry optimization on the Cu(III) [(10 (4-BrPh) 5,15
bisF5PhC)] (Fig. 4C). Subsequent time-dependent density functional
theoretical calculations on both species support the experimentally
observed UV/vis spectra (performed in THF/H2O) reasonably well
(Fig. 4D, E). Fig. 4D exhibits the characteristic spectrum of the Cu(III)
corrole 7a with a B band (Soret Band) maximum of 405 nm and
a broader Q-band region around 550 nm. By comparing the results
obtain from the calculations both spectral features (B- and Q-bands)
could be reproduced and moreover the bathochromic shift of about
Dl¼30 nm is also consistent to spectroelectrochemical data obtained
for the first reduction,39 when calculating the corresponding reduced
Cu(II)ecorrole moiety (Fig. 4E). Even the spectral features are con-
sistent, observable by the emerging shoulder in the B-band region
valent character to the copper-corrolate
electron density from the corrolate trianion into the empty 3dx2ꢁy2
orbital via interactions induced by a saddling deformation of
the macrocycle. In the latter case, the Cu(III)-corrolate3ꢁ system is
s-bonds, (b) transfer of
sep
2ꢁ
in equilibrium with a d9-species with Cu(II)corrolateꢂ
radical
character, which can adopt either an antiferromagnetically coupled
singlet state (saddle-shape geometry) or a planar triplet state.31e38
The well resolved 1H NMR spectrum observed in dichloromethane
at 283 K (Fig. 2A) reflects, that the equilibrium for the copper A2B-
corrole 3 lies on the side of a diamagnetic species where almost no
charge redistribution between the corrole ligand p-orbitals and the
3dx2ꢁy2 orbital occurs.
In alkaline THF/H2O/K3PO4 media the equilibrium is shifted to-
wards the Cu(II)-corrolateꢂ2ꢁ dianion radical species best seen by the
vanished pyrrole proton resonances and the increased line broad-
ening of the proton resonances stemming from the phenyl moiety. All
proton spin systems therefore possess faster relaxation rates caused
by the increased paramagnetic property of the central copper ion.
Clearly, the pyrrole proton resonances are most sensitive, due to the
close proximity of the pyrrole protons to the paramagnetic copper
central atom. Furthermore, an ESR signal was observed at room
temperature in dichloromethane (Supplementary datadFig. 52).
Complementary, the UV/vis absorption spectra of [CuIII(10-Br-Ph-
5,15-bis-F5PhC)], 4, illustrated in Fig. 2B, exhibit a bathochromic
shift of the Soret-band maximum from 407 to 433 nm after the
addition of aq K3PO4 solution. A similar trend was published earlier,
by employing spectroelectrochemical and ESR studies on similar
highly substituted copper A3-corroles.39 All those findings could not
be observed in toluene/H2O/K3PO4. Hence, we hypothesize that in
THF/H2O/K3PO4 2mꢁixture (water and solvent miscible) preferably the
Cu(II)-corrolateꢂ diradical species is existent, whereas in toluene/
H2O/K3PO4 the reactant dominates in the Cu(III) form.
(
lmax calcd
,
¼435 nm and lexp¼433 nm) and a more defined Q-band
emerging at lcalcd¼570 nm versus lexp¼590 nm. The electronic
transitions are further described in the electronic Supplementary
data (Fig. 47e51).
3. Conclusion
In summary, wehavedeveloped a procedurefor SuzukieMiyaura
reactions at 80 ꢀC with a SPhos/Pd2(dba)3 catalyst system and
a milder synthesis routineat 45 ꢀC with a Pd-precatalyst system, that
allows the coupling of corrole bromides with awide range of boronic
acid/ester derivatives and exhibits excellent functional group tol-
erance. Moreover, the fast catalytic process of the latter catalyst
system 5 at lower temperature offers an excellent way to couple
heterocyclic boronic acids with corrole bromides.
Depending on the solvents used in the SuzukieMiyaura re-
action, a bathochromic shift in UV/vis absorption spectra and in-
creased line broadening of proton resonances in the 1H NMR

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4247
Fig. 2. A. Time-course 1H NMR spectra and B. UV/vis spectra of the reduction process of Cu(III) corrole aryl bromide 3 in pure (i) THF-d8 (ii) in a mixture of THF-d8/D2O and (iii) in
a mixture of THF-d8/D2O/K3PO4.
spectra of the copper-[(10-(4-BrPh)-5,15-bis-F5PhC)] corrole com-
plexes was observed. Therefore, the formal oxidation state of cop-
per is not self-evident in all cases and has to be clarified by further
investigations.
4. Experimental section
4.1. General experimental
Most of the SuzukieMiyaura coupled products form stable Cu(III)
corroles in solution and in the solid state. Activating substituents
however, like phenyl- or pyrimdyl-groups lead to coupled products
exhibiting significant Cu(II)-character. The DFT geometry optimized
structure of 7a matches well with the crystal structure and TD-DFT
approaches support the band-shift observed in UV/vis spectra and
moreover indicate a conformational change from a saddled Cu(III)
All chemicals were purchased from SigmaeAldrich or Acros and
used without further purification. Reagent grade solvents were
purchased from Fischer chemicals and distilled prior to use. THF
was distilled over sodium and benzophenone under an argon at-
mosphere and toluene was distilled over sodium/potassium alloy
and benzophenone under an argon atmosphere and was stored
ꢀ
over molecular sieves (4 A) upon use. Acetone (HPLC-grade) was
ꢀ
ꢀ
corrole species with CueN distances of dCueN¼1.88e1.89 A to a more
stored over molecular sieves (3 A) upon use.
relaxed geometry of the corresponding Cu(II) corrole with calculated
Proton (1H NMR) and carbon (13C NMR) spectra were recorded
on Bruker DRX 500 spectrometer equipped with a cryogenically
ꢀ
CueN distances of dCueN¼1.92e1.93 A.

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A
4
7a
7b
7c
7d
7e
400
500
600
700
Wavelength / nm
B
3000
2000
1000
0
-1000
-2000
-3000
-4000
-5000
2600
2800
3000
3200
3400
3600
3800
4000
field (G)
Fig. 3. A. UV/vis spectra of 4 as reference Cu(III) corrole species and the compounds 7aee exhibiting increased Cu(II) character in dichloromethane solution. B. ESR spectrum of 7a in
dichloromethane solution at 298 K.
cooled probe (TXI) at 500 and 125.8, respectively, 19F NMR spectra
were recorded on a Bruker AV 600 MHz or a Varian Inova 300 MHz
spectrometer at 564.7 and 282.4 MHz, respectively, and phospho-
rus (31P NMR) NMR spectra were recorded on a Bruker 200 MHz
spectrometer at 80.9 MHz.
TLC was performed by using Fluka silica gel 60 F254 (0.2 mm) on
aluminium plates. Silica-gel columns for chromatography were
prepared with E. Merck silica gel 60 (0.063e0.20 mesh ASTM).
4.2. Synthesis of the Fb-A2B-corrole precursor (3)
The chemical shifts are given in parts per million (ppm) on the
1
delta scale (
d
) and are referenced to TMS (
d
¼0 ppm) for H, 65% aq
Synthesis according to the procedure of Gryko and
Koszarna401.281 g (4.1 mmol, 2 equiv) of 2 and 412 mg (2.2 mmol,
1 equiv) of 1 were dissolved in 200 ml of methanol. Subsequently,
a solution of 10 ml concentrated HCl in 200 ml of water was added.
This suspension was stirred at room temperature (rt) for 1 h and
extracted with CHCl3 (2ꢃ 50 ml). The combined organic phases
were washed with water (3ꢃ 50 ml), dried over Na2SO4 and con-
centrated to 40 ml. This solution and a solution of 1.2 g of DDQ
(5.3 mmol, 2.5 equiv) in 32 ml DCM/toluene (3:1) were
H3PO4 (
d
¼0 ppm) for 31P and TFA for 19F. Abbreviations for NMR data:
s¼singlet, d¼doublet, t¼triplet, q¼quartet, dd¼doublet of doublets,
dt¼doublet of triplets, dq¼doublet of quartets, tt¼triplet of triplets,
m¼multiplet. Mass spectra were collected on a Finnigan LCQ
DecaXPplus Ion trap Mass spectrometer with ESI ion source and
MALDI-TOF measurements were collected with a Bruker Autoflex III
Smartbeam spectrometer, whereby a matrix:sample ratio of 10:1 was
used.

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M. Konig et al. / Tetrahedron 67 (2011) 4243e4252
4249
Fig. 4. A. Molecular structure of one of the two independent Cu-corrole molecules in crystals of 7a (ORTEP, displacement ellipsoids at the 30% probability level, H atoms are omitted
ꢀ
ꢀ
for clarity). Selected bond lengths [A] and angles [ ]: Cu1eN1 1.876 (5), Cu1eN2 1.880 (5), Cu1eN3 1.892 (5), Cu1eN4 1.891 (5), N1eCu1eN2 82.0 (2), N1eCu1eN4 91.6 (2),
ꢀ
ꢀ
N2eCu1eN3 91.0 (2), N3eCu1eN4 97.3 (2). The corresponding distances [A] and angles [ ] for the second complex are: Cu2eN5 1.900 (4), Cu2eN6 1.896 (4), Cu2eN7 1.887 (5),
Cu2eN8 1.909 (5), N5eCu2eN6 91.7 (2), N5eCu2eN8 96.9 (2), N6eCu2eN7 81.4 (2), N7eCu2eN8 91.9 (2) B. Ground state DFT-optimized structures of Cu(III) corrole 7a and C. The
corresponding Cu(II) corrole species. D. Experimentally (solid, red line) observed and calculated (dashed, black line) UV/vis spectra of Cu(III) corrole 7a and the E. the corresponding
experimentally (solid, red line) observed and calculated (dashed, black line) electronic transition spectra of the Cu(II) corrole analogue.
simultaneously added to 40 ml vigorously stirred DCM. The re-
action mixture was stirred for 15 min at room temperature, con-
centrated to ¼ of the initial volume and chromatographed (silica,
CHCl3/hexanes 1:1). The fluorescent bands were collected and
evaporated to dryness. 698 mg (0.88 mmol, 40%). 1H NMR
solution was purged with nitrogen for 10 min. 502 mg (2.8 mmol,
3 equiv) of anhydrous copper(II)acetate were placed into a Schlenk
tube, followed by the addition of the corrole/THF solution under
nitrogen counter flow. This mixture was stirred for 15 min at room
temperature under nitrogen atmosphere evaporated to dryness
and redissolved in 100 ml DCM. This solution was washed three
times with 30 ml water. Evaporation to dryness afforded 687.9 mg
(0.81 mmol, 91% yield) of the pure product (purple solid). 1H NMR
(200 MHz, CDCl3, 30 ꢀC):
d
¼9.12 (d, J(H,H)¼4 Hz, 2H, Hb), 8.695 (m,
4H, Hb) 8.57 (d, J(H,H)¼4 Hz, 2H, Hb), 8.05 (d, J(H,H)¼7 Hz, 2H, Ho),
7.91 (d, J(H,H)¼7 Hz, 2H, Hm); MS (ESIþ): m/z: calcd for
C37H15BrF10N7: 784.03; found: 785.08 [MþH]þ; UV/vis (CHCl3)
lmax¼408, 561, 608 nm. Other analytical data were consistent with
literature values.19
(600 MHz, CD2Cl2, 25 ꢀC):
d
¼8.02 (s, 2H, Hb), 7.65 (d, J(H,H)¼8 Hz,
2H, Ho), 7.45 (m, 4H, Hm, Hb), 7.26 (d, J(H,H)¼4 Hz, 2H, Hb), 7.20 (d,
J(H,H)¼4 Hz, 2H, Hb); 13C NMR (125.8 MHz, CD2Cl2, 25 ꢀC):
¼131.7
d
(CH), 131.4 (CH), 130.2 (CH), 125.9 (CH), 125.1 (CH), 122.8 (CH); 19F
NMR (564.7 MHz, CD2Cl2, 25 ꢀC):
d
¼ꢁ138.03 (s, 4F, Fo), ꢁ153.33 (d,
4.3. Cu-metallation reaction (4)
3J(F,F)¼20 Hz, 2F, Fp), ꢁ161.73 (m, 4F, Fm); MS (ESIꢁ): m/z: calcd for
C37H15BrCuF10N7: 845.94; found: 846.20 [M]ꢁ; UV/vis (CHCl3)
lmax¼406, 548, 617 nm.
Synthesis according to the procedure of Maes et al.16 698.2 mg
(0.89 mmol, 1 equiv) of 3 were dissolved in 130 ml THF and this

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M. Konig et al. / Tetrahedron 67 (2011) 4243e4252
13
4.4. Synthesis of precatalyst 5
Hb); C NMR (125.8 MHz, CD2Cl2, 25 ꢀC):
d
¼133.8 (CH), 132.6 (CH),
131.5 (CH), 130.3 (CH), 129.3 (CH), 128.5 (CH), 128.3 (CH), 127.8 (CH),
Synthesis in analogy to27 under N2 atmosphere,1 mmol Pd(OAc)2
and 1.04 mmol 2-amino-biphenyl were dissolved in 6 ml anhydrous
toluene, heated to 60 ꢀC and stirred for 60 min, whereby the solution
turned from red to yellowish grey and a grey precipitate formed.
Furtheron, thetoluenewasremovedviacannula and thesolutionwas
cooled to ambient temperature. The residue was washed with tolu-
ene, and 6 ml acetone and 3 mmol LiCl were added and the solution
slowly turned olive green. After 60 min of stirring, 0.95 mmol XPhos
were added in five portions and the solution was stirred for further
120 min, during which a grayish white solid precipitated. After
a major amount of the solvent was removed via cannula,1.5 ml MTBE
and 3 ml pentane were added. The solution was cooled to 0 ꢀC and
after 60 min the product was collected by filtration and washed with
124.4 ppm (CH); 19F NMR (282.4 MHz, CD2Cl2, 25 ꢀC):
d¼ꢁ138.09 (dd,
3J(F,F)¼20 Hz, 4J(F,F)¼8 Hz, 4F, Fo), ꢁ153.48 (t, 3J(F,F)¼20 Hz, 2F, Fp),
ꢁ161.79 ppm (dt, 3J(F,F)¼20 Hz, 4J(F,F)¼8 Hz, 4F, Fm); MS (ESIꢁ): m/z:
calcd for C43H17CuF10N4: 842.06; found: 842.07 [M]ꢁ. UV/vis (CH2Cl2)
lmax¼401, 557, 623 nm.
4.6.2. Compound 7b: Cu 10-(4-(4-methylphenyl-)phenyl-)5,15-bis-
pentafluorophenylcorrole. Eluent hexanes/DCM 2:1. 72 mg (84%
yield). 1H NMR (500 MHz, CD2Cl2, 25 ꢀC):
d
¼8.01 (s, 2H, Hb), 7.7 (d,
J(H,H)¼8 Hz, 2H, Ho), 7.66 (d, J(H,H)¼8 Hz, 2H, Hm), 7.61 (d, J(H,H)¼
8 Hz, 2H, Ho), 7.47 (m, 4H), 7.32 (m, 4H); 2.42 ppm (s, 3H, HMe); 13
NMR (125.8 MHz, CD2Cl2, 25 ꢀC):
¼133.1 (CH), 131.9 (CH), 130.4
C
d
(CH), 130.1 (CH), 127.3 (CH), 127.2 (CH), 127.0 (CH), 123.5 (CH), 21.4
water. Yield: 520 mg (66%). 31P NMR (80.9 MHz, CDCl3, 30ꢀC):
d¼67.9,
(CH3); 19F NMR (564.7 MHz, CD2Cl2, 25 ꢀC):
d
¼ꢁ138.06 (d, 3J(F,F)¼
65.6 ppm (two signals due to two different rotamers); MS (ESIþ): m/z:
20 Hz, 4F, Fo), ꢁ153.48 (m, 2F, Fp), ꢁ161.79 ppm (t, 3J(F,F)¼20 Hz, 4F,
Fm); MS (ESIꢁ): m/z: calcd for C44H19CuF10N4: 856.07; found: 856.40
[M]ꢁ. UV/vis (CH2Cl2) lmax¼404, 436 (sh), 554, 619 nm.
calcd for C45H59NPPdCl: 785.31; found: 750.40 [MꢁClꢁ]þ; 582.40
[MꢁC15H23
]
þ 1HNMRcomplexbutconsistentwithliterature.4 Crystal
structure is available (CSDC: 813705 and 813706).
4.6.3. Compound 7c: Cu 10-(4-(2-naphthyl-)phenyl-)5,15-bispenta-
fluorophenylcorrole. Eluent hexanes/DCM 2:1. 75 mg (84% yield). 1H
4.5. General procedure for the Suzuki-reaction with alkyl and
alkenylboronic acids- and boronic acid esters using SPhos and
Pd2(dba)3 as catalyst system
NMR (500 MHz, CD2Cl2, 30 ꢀC):
d
¼8.20 (s, 1H, Hnaphth), 7.99 (m, 4H),
7.90 (m, 4H), 7.74 (d, J(H,H)¼8 Hz, 2H, Hm), 7.53 (m, 2H, Hnaphth),
7.48 (d, J(H,H)¼4 Hz, 2H, Hb), 7.375 (d, J(H,H)¼4 Hz, 2H, Hb), 7.295
(d, J(H,H)¼4 Hz, 2H, Hb); 13C NMR (125.8 MHz, CD2Cl2, 30 ꢀC):
Compound 4 0.1 mmol (1 equiv), 0.2 mmol (2 equiv) of the
corresponding boronic acid, 63.7 mg (0.3 mmol, 3 equiv) of K3PO4,
2.3 mg of Pd2(0)dba3 (5 mol-% Pd) and 2.0 mg of SPhos (ligand to
metal ratio 2:1) were filled in a Schlenk-tube, which was sealed
with a Teflon cap. The tube was evacuated and backfilled with ni-
trogen (this process was repeated two times), followed by the ad-
dition of 32 ml of toluene (29.1 ml toluene and 2.9 ml water for
boronic acid esters) under nitrogen counter flow. The Schlenk-tube
was sealed again, and the resulting mixture was stirred for 1e24 h
at 80 ꢀC under nitrogen atmosphere. After the completion of the
reaction (TLC monitoring), the reaction mixture was suction filtered
over a Celite plug (1 cm), the filtrate was evaporated to dryness The
residue was dissolved in 30 ml DCM, washed with 10 ml of water
(three times), the organic phase was dried over anhydrous Na2SO4,
evaporated to dryness and purified via column chromatography
(silica/varying eluents).
d
¼133.5 (CH), 132.2 (CH), 131.1 (CH), 129.5 (CH), 128.4 (CH), 127.5
(CH), 127.4 (CH), 126.9 (CH), 126.3 (CH), 126.2 (CH), 124.0 (CH); 19F
NMR (564.7 MHz, CD2Cl2, 30 ꢀC):
d
¼ꢁ138.02 (d, 3J(F,F)¼20 Hz, 4F,
Fo), ꢁ153.43 (t, 3J(F,F)¼20 Hz, 2F, Fp), ꢁ161.77 ppm (t, 3J(F,F)¼20 Hz,
4F, Fm); MS (ESIꢁ): m/z: calcd for C47H19CuF10N4: 892.07; found:
892.40 [M]ꢁ; UV/vis (CH2Cl2) lmax¼400, 437 (sh), 545, 611 nm.
4.6.4. Compound 7d: Cu 10-(4-(E-phenylvinyl-)phenyl-)5,15-bis-
pentafluorophenylcorrole. Eluent hexanes/DCM 2:1. 70 mg (80%
yield). 1H NMR (500 MHz, CD2Cl2, 25 ꢀC):
d
¼8.01 (s, 2H, Hb), 7.60 (d,
J(H,H)¼7 Hz, 2H, Ho), 7.59 (m, 4H), 7.47 (m, 2H, Hb), 7.40 (t, J(H,H)¼
7 Hz, 2H, Hm), 7.26 ppm (m, 7H); 13C NMR (125.8 MHz, CD2Cl2,
25 ꢀC):
d
¼136.1 (CH), 134.9 (CH), 134.0 (CH), 133.9 (CH), 133.2 (CH),
133.2 (CH), 132.5 (CH), 131.0 (CH), 130.7 (CH), 129.5 (CH), 127.6 ppm
(CH); 19F NMR (564.7 MHz, CD2Cl2, 30 ꢀC):
d
¼ꢁ138.03 (3J(F,F)¼
19 Hz, 4F, Fo), ꢁ153.42 (t, 3J(F,F)¼19 Hz, 2F, Fp), ꢁ161.76 ppm (t,
3J(F,F)¼19 Hz, 4F, Fm); MS (ESIꢁ): m/z: calcd for C45H19CuF10N4:
868.07; found: 868.33 [M]ꢁ; UV/vis (CH2Cl2) lmax¼402, 436 (sh),
550, 616 nm. Product contains an amount of Z-isomer.
4.6. General procedure for the Suzuki cross-coupling reaction
with heteroaromatic boronic acids and boronic acid esters
employing precatalyst 5
Compound 4 0.05 mmol (1 equiv) and 0.15 mmol K3PO4 were
placed in a Schlenk tube and dissolved in 16 ml of a degassed THF/
H2O mixture (5:3). The solution was purged with N2 for further
30 min, followed by the addition of 0.15 mmol of the corresponding
boronic acid (or ester, respectively) and 10 mol % of precatalyst 5.
The Schlenk tube was sealed, and the reaction mixture was heated
to 45 ꢀC and stirred for 24 h (unless not denoted differently for the
specific reaction) under N2. After completion (TLC and ESI-MS
monitoring), the reaction mixture was evaporated to dryness, the
residue was dissolved in 30 ml of CHCl3 and washed twice with
10 ml of water. The organic phase was then dried over anhydrous
Na2SO4, evaporated to dryness and purified via column chroma-
tography (silica/varying eluents).
4.6.5. Compound 7e: Cu 10-(4-(2-dimethylaminopyrimidine-5-yl-)
phenyl-)5,15-bispentafluorophenylcorrole. Eluent
DCM/MeOH
¼8.66
200:1. 30 mg (68% yield). 1H NMR (500 MHz, CD2Cl2, 10 ꢀC):
d
(s, 2H, Hpyrim), 7.96 (s, 2H, Hb), 7.69 (d, J(H,H)¼7 Hz, 2H, Ho), 7.62 (d,
J(H,H)¼7 Hz, 2H, Hm), 7.49 (s, 2H, Hb), 7.325 (d, J(H,H)¼4 Hz, 2H, Hb),
7.24 (s, 2H, Hb), 3.22 ppm (s, 6H, Hmethyl)
13C NMR (125.8 MHz,
CD2Cl2, 10 ꢀC):
d
¼156.9 (CH), 132.8 (CH), 131.9 (CH), 130.7 (CH),
126.3 (CH), 126.2 (CH), 124.2 (CH), 38.1 (CH3); 19F NMR (564.7 MHz,
CD2Cl2, 30 ꢀC):
d
¼ꢁ138.05 (d, 3J(F,F)¼20 Hz, 4F, Fo), ꢁ153.39 (t,
3J(F,F)¼20 Hz, 2F, Fp), ꢁ161.74 ppm (t, 3J(F,F)¼20 Hz, 4F, Fm); MS
(ESIþ): m/z: calcd for C43H20CuF10N7: 887.09; found: 888.33
[MþH]þ; MS (ESIꢁ): m/z: calcd for C43H20CuF10N7: 887.09; found:
887.40 [M]ꢁ; UV/vis (CH2Cl2) lmax¼403, 551, 623 nm.
4.6.1. Compound 7a: Cu 10-(4,10-biphenyl-1-yl)5,15-bispentafluoroph-
enylcorrole. Eluent hexanes/DCM 2:1. 66 mg (78% yield). 1H NMR
4.6.6. Compound 7f: Cu 10-(4-(6-(1-piperazinyl-)pyridine-3-yl-)
phenyl-)5,15-bispentafluorophenylcorrole. Eluent CHCl3/MeOH 10:1
with 1% TEA. 39 mg (84% yield). No NMR data could be obtained
due to the fast decomposition of the product. MS (ESIþ): m/z: calcd
for C46H24CuF10N7: 927.12; found: 928.13 [MþH]þ; MS (ESIꢁ): m/z:
calcd for C46H24CuF10N7: 927.12; found: 927.40 [M]ꢁ; UV/vis
(500 MHz, CD2Cl2, 25 ꢀC):
d¼8.01 (d, J(H,H)¼4 Hz, 2H, Hb), 7.75 (d,
J(H,H)¼8 Hz, 2H, Ho), 7.71 (d, J(H,H)¼8 Hz, 2H, Hm), 7.66 (d, J(H,H)¼
8 Hz, 2H, Ho), 7.49 (m, 2H, Hm), 7.46 (d, J(H,H)¼4 Hz, 2H, Hb), 7.40 (m,
1H, Hp), 7.32 (d, J(H,H)¼4 Hz, 2H, Hb), 7.26 ppm (d, J(H,H)¼4 Hz, 2H,

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M. Konig et al. / Tetrahedron 67 (2011) 4243e4252
4251
(CHCl3) lmax¼430, 544, 592 nm. The product is very unstable, and
both, in solid and solution, partial decomposition and reduction to
the corresponding Cu(II) species is observed.
4.6.11. Compound 7k: Cu 10-(4-aminophenyl-)5,15-bispentafluorop-
henylcorrole. Eluent DCM/hexanes 10:1. 10 mg (23% yield). 1H NMR
(500 MHz, CD2Cl2, 25 ꢀC):
d
¼7.97 (s, 2H, Hb), 7.64 (d, J(H,H)¼8 Hz,
2H, Ho), 7.59 (d, J(H,H)¼8 Hz, 2H, Hm), 7.49 (d, J(H,H)¼8 Hz, 2H, Ho),
7.43 (d, J(H,H)¼4 Hz, 2H, Hb), 7.31 (d, J(H,H)¼4 Hz, 2H, Hb), 7.23 (d,
J(H,H)¼4 Hz, 2H, Hb), 6.76 (d, J(H,H)¼8 Hz, 2H, Hm), 3.83 ppm (s, H,
4.6.7. Compound 7g: Cu 10-(4-(1-phenylsulfonylindole-3-yl-)phenyl-)
5,15-bispentafluorophenylcorrole. Eluent hexanes/DCM 2:1. A sec-
ond column chromatography was necessary (silica, hexanes/DCM
NH2); 13C NMR (125.8 MHz, CD2Cl2, 25 ꢀC):
d¼132.8 (CH), 131.3
1:1). 37 mg (72% yield). 1H NMR (500 MHz, CD2Cl2, 10 ꢀC):
d¼8.10
(CH), 130.2 (CH), 128.1 (CH), 126.7 (CH), 126.1 (CH), 123.2 (CH), 115.4
19
(d, J(H,H)¼8.2 Hz, 1H, indolyl-H7), 8.02 (br s, 2H, Hb), 7.98 (d,
J(H,H)¼7.5 Hz, 2H, phen-sulfonyl Ho), 7,91 (m(overlapping), 1H,
indolyl H4), 7.89 (d(overlapping), 2H, phenyl Hm), 7,86 (s(over-
lapping), 1H, indolyl H2), 7.77 (d, J(H,H)¼7.9 Hz, 2H, phenyl Hm),
7.70 (d, J(H,H)¼7.9 Hz, 2H, phenyl Ho) 7.57e7.62 (m, 1H, phen-
sulfonyl Hp), 7.45 (br s (overlapping), 2H, Hb), 7.40e7.43 (m, 1H,
indolyl H5), 7.33e7.37 (m, 1H, indolyl H6), 7.33 (br s, 2H, Hb), 7.28
(CH); F NMR (564.7 MHz, CD2Cl2, 30 ꢀC):
d
¼ꢁ138.04 (d, 3J(F,F)¼
17 Hz, 4F, Fo), ꢁ153.39 (t, 3J(F,F)¼19 Hz, 2F, Fp), ꢁ161.80 ppm (t,
3J(F,F)¼19 Hz, 4F, Fm); MS (ESIþ): m/z: calcd for C43H18CuF10N5:
857.07; found: 858.07 [MþH]þ; MS (ESIꢁ): m/z: calcd for
C43H20CuF10N7: 857.07; found: 857.47 [M]ꢁ; UV/vis (CH2Cl2)
lmax¼404, 552, 616 nm.
(br s, 2H, Hb); 13C NMR (125.8 MHz, CD2Cl2, 10 ꢀC):
d
¼132.9 (CH,
4.6.12. Compound 7l: Cu 10-(4-(4-benzo[b]thiophen-2-yl-)phenyl-)
5,15-bispentafluorophenylcorrole. Eluent hexanes/DCM 2:1. 20 mg
2C, Cb), 131.2 (CH, 2C, phenyl Co), 130.1 (CH, 1C, phen-sulfonyl Cp),
130.8 (CH, 2C, Cb), 129.9 (CH, 2C, Cb), 128.1 (CH, 2C, phenyl Cm),
127.5 (CH, 2C, phen-sulfonyl Co), 127.5 (CH, 2C, phen-sulfonyl Cm),
125.7 (CH, 1C, indolyl C5), 124.5 (CH, 1C, indolyl C6), 123.9 (CH, 2C,
Cb), 123.9 (CH, 1C, indolyl C2), 121.0 (CH, 1C, indolyl C4), 114.4 (CH,
(45% yield). 1H NMR (500 MHz, CD2Cl2, 10 ꢀC):
d
¼8.03 (2H, Hb), 7.88
(2H, Hm), 7.88 (2H, Hb), 7.67 (2H, Ho), 7.72 (s, 1H, Benzothienyl-H3),
7.71 (d, 1H, Benzothienyl-H7), 7.59 (d, J¼7.20 Hz, 1H, Benzothienyl-
H4), 7.34e7.41 (m, 1H, Benzothienyl-H6), 7.33 (2H, Hb), 7.28 (2H,
Hb), 7.13e7.18 (m, 1H, Benzothienyl-H5). 13C NMR (125.8 MHz,
1C, indolyl-C7); 19F NMR (282.4 MHz, CD2Cl2, 25 ꢀC):
d¼ꢁ138.02
(dd, 3J(F,F)¼21 Hz), ꢁ153.38 (t, 3J(F,F)¼21 Hz, 2F, Fp), ꢁ161.74 ppm
(dt, 3J(F,F)¼21 Hz, 4J(F,F)¼7.5 Hz, 4F, Fm); MS (ESIꢁ): m/z: calcd for
C51H21CuF10N5O2S: 1021.06; found: 1021.25 [M]ꢁ, 880.23
[Mꢁphenylsulfonyl]ꢁ; UV/vis (CH2Cl2) lmax¼401, 430(sh), 5550,
610 nm.
CD2Cl2, 25 ꢀC):
d
¼131.7 (CH),130.6 (CH),129.3 (CH),128.4 (CH),125.2
(CH), 124.0 (CH), 123.9 (CH), 122.2 (CH), 121.8 (CH), 119.5 (CH), 119.3
(CH); 19F NMR (282.4 MHz, CD2Cl2, 25 ꢀC):
d
¼ꢁ138.07 (br d, 3J(F,F)¼
20 Hz, 4F, Fo), ꢁ153.39 (t, 3J(F,F)¼20 Hz, 2F, Fp), ꢁ161.77 ppm (m, 4F,
Fm); MS (MALDIþ): m/z: calcd for C45H17CuF10N4S: 898.03; found:
898.07 [M]þ; UV/vis (CH2Cl2) lmax¼402, 431(sh), 547, 606 nm.
4.6.8. Compound 7h: Cu 10-(4-(benzo[b]furan-2-yl-)phenyl-)5,15-
bispentafluorophenylcorrole. Eluent hexanes/DCM 1:1. 36 mg (82%
4.7. DFT-calculations
yield). 1H NMR (500 MHz, CD2Cl2, 25 ꢀC):
d¼8.00 (br s, 2H, Hb), 7.71
(d, J(H,H)¼8.0 Hz, 2H, Hm), 7,65 (d, J(H,H)¼7.7 Hz,1H, Benzofuranyl-
H4), 7.57 (d, J(H,H)¼7.8 Hz, 1H, Benzofuranyl-H7), 7.48 (d(over-
lapping), 2H, Hb), 7.45 (m, 1H, Benzofuranyl-H5), 7.36e7.32 (m, 1H,
Benzofuranyl-H6), 7.33 (m(overlapping), 2H, Hb), 7.27 (m(over-
lapping), 2H, Ho), 7.26 (m(overlapping), 2H, Hb), 7.21 (s, 1H,
Benzofuranyl-H3); 13C NMR (125.8 MHz, CD2Cl2, 25 ꢀC): 131.3 (CH,
2C, Cb), 130.3 (CH, 2C, Cm), 129.5 (CH, 2C, Cb), 125.2 (CH, 2C, Cb),
125.0 (CH, 1C, Benzofuranyl-C5), 124.1 (CH, 1C, Benzofuranyl-C6),
123.2 (CH, 2C, Cb), 122.5 (CH, 2C, Co), 120.4 (CH, 1C, Benzofuranyl-
Calculationswereperformedbyusing the Gaussian 03package of
programs.41 The electronic structure calculations were based on the
Kohn-Sham density functional theory (KS-DFT) with Becke’s three-
parameter hybrid functional (B3LYP) and at DFT/mPW1PW91le-
vel.42,43 Relativistic electronic core potentials (ECPs)44 were used to
describe the electrons of Cu atoms. The basis set of Peterson and
Puzzarini45 was augmented by adding one set of polarization func-
tions on all atoms and one set of diffuse functions on all non-
hydrogen atoms. For C and H atoms all-electron split-valence 6-
311þG(d,p) basis sets supplemented with a single set of diffuse
functions on carbon atoms were employed. The vertical singlet
electronic states were studied using the extended Koopman’s the-
orem with time-dependent PBE0 density functional method (TD-
PBE0/BS-II).46 Energies and dipole moments reported herein were
evaluated using the second- and fourth-order Moeller-Plesset per-
turbation theory [MP2(full)/BS-II or MP4(SDQ)/BS-II] in combina-
tion with PBE0 parametrization [PBE0/BS-I].
C4), 110.5 (CH, 1C, Benzofuranyl-C7), 101.5 (CH, 1C, Benzofuranyl-
19
C3); F NMR (282.4 MHz, CD2Cl2, 25 ꢀC):
d
¼ꢁ138.08 (dd, 3J(F,F)¼
21 Hz, 4J(F,F)¼7.8 Hz, 4F, Fo), ꢁ153.40 (t, 3J(F,F)¼21 Hz, 2F, Fp),
ꢁ161.76 ppm (dt, 3J(F,F)¼21 Hz, 4J(F,F)¼7.8 Hz, 4F, Fm); MS (ESIꢁ):
m/z: calcd for C45H17CuF10N4O: 882.05; found: 882.27 [M]ꢁ; UV/vis
(CH2Cl2) lmax¼403, 431(sh), 546, 601 nm;
4.6.9. Compound 7i: Cu 10-(4-(m-nitro-phenyl)phenyl-)5,15-bis-
pentafluorophenylcorrole. Eluent hexanes/DCM 2:1. 35 mg (79%
yield). 1H NMR (500 MHz, CD2Cl2, 10 ꢀC):
d
¼8.51 (s, 1H, nitrophen-
4.8. Crystal structure determination
H20), 8.29 (d, J(H,H)¼8.3 Hz,1H, nitrophen-H40), 8.22 (br m, 2H, Hb),
8.00 (J(H,H)¼8.2 Hz, 1H, nitrophen-H60), 7.78e7.84 (m, 1H, nitro-
phenn-H50), 7.72 (d, J(H,H)¼7.5 Hz, 2H, Hm), 7.49 (br s, 2H, Hb), 7.40
(m, 2H, Ho), 7.23 (br s, 2H, Hb), 7.29 (br s, 2H, Hb); 13C NMR
Crystalsof 5and7aweremountedonaMitegenMicromountwere
automatically centred on a Bruker SMART X2S benchtop crystallo-
graphic system. Intensity measurements were performed using
(125.8 MHz, CD2Cl2, 25 ꢀC):
d
¼133.4 (CH), 130.6 (CH), 129.5 (CH),
monochromated (doubly curved silicon crystal) Mo Ka-radiation
ꢀ
126.2 (CH), 124.5 (CH), 122.4 (CH), 122.0 (CH), 121.3 (CH), 118.5 (CH),
(0.71073 A) from a sealed microfocus tube. APEX2 software was used
for preliminary determination of the unit cell.47 Determinations of
integrated intensities and unit cell refinement were performed using
SAINT.48 Data were corrected for absorption effects with SADABS
using the multi-scan technique.49 The structures were solved by di-
rect methods (SHELXS-97)51 and refined by full-matrix least-squares
on Fo2 (SHELXL-97).50,51 The H atoms were calculated geometrically,
and a riding model was applied during the refinement process.
The cell parameters of 7a suggest a monoclinic space group, but
the tolyl substituent could not be resolved in P21/c. Structure so-
lution in the triclinic space group Pꢁ1 reveals a disorder of the tolyl
19
118.2 (CH); F NMR (282.4 MHz, CD2Cl2, 25 ꢀC):
d¼ꢁ138.08 (br d,
3J(F,F)¼22 Hz, 4F, Fo), ꢁ153.36 (t, 3J(F,F)¼22 Hz, 2F, Fp), ꢁ161.79 ppm
(bt, 3J(F,F)¼22 Hz, 4F, Fm); MS (MALDIþ): m/z: calcd for
C43H16CuF10N5O2: 887.04; found: 887.22 [M]þ; UV/vis (CH2Cl2)
lmax¼403, 422(sh), 547, 604 nm;
4.6.10. Compound 7j: Cu 10-(4-(2,4,6-tri(isopropyl)-phenyl)phenyl-)
5,15-bispentafluorophenylcorrole. Only traces of the reaction prod-
uct were observed in the reaction mixture: MS (MALDIþ): m/z:
calcd for C52H35CuF10N4: 968.20; found: 968.41 [M]þ;

€
M. Konig et al. / Tetrahedron 67 (2011) 4243e4252
4252
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14. Barata, J. F. B.; Neves, M. G. P. M. S.; Tome, A. C.; Cavaleiro, J. A. S. J. Porphyrins
Phthalocyanines 2009, 13, 415.
and one pentafluorophenyl substituent. The structure was refined
with two positions of each disordered aromatic moiety rotated
about the CipsoeCpara positions. Their site occupancy factors were
refined to w52:48 for both disordered pentafluorophenyl and one
phenyl-group and to 55:45 for the other phenyl-moiety. As this
disorder model is still not yielding acceptable structural parameters
of the disordered groups, the bond distances were fixed with the
DFIX command and the rings flattened with FLAT command. All 86
restrains originate form this description of the disorder. Crystals of
the precatalyst 5 contain two molecules of chloroform one of which
is disordered. Hence, the program SQUEEZE,52 a part of the PLATON
package of crystallographic software, was used to calculate the
solvent disorder area and remove its contribution to the overall
intensity data.
15. Maes, W.; Ngo, T. H.; Vanderhaeghen, J.; Dehaen, W. Org. Lett. 2007, 9, 16.
16. Ngo, T. H.; Nastasi, F.; Puntoriero, F.; Campagna, S.; Dehaen, W.; Maes, W. J. Org.
Chem. 2010, 75, 2127.
17. Broring, M.; Milsmann, C.; Ruck, S.; Kohler, S. J. Organomet. Chem. 2009, 694,
1011.
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Acknowledgements
This work was supported by the Austrian Science Fund, projects
P-18384 (to W.S.) and the European Community (EU-NMR, contract
No. RII 3-026145).
We would like to thank Dr. Manuela List for her support in
measuring our samples on the ESI-Q-TOF mass spectrometer.
30. Zim, D.; Buchwald, S. L. Org. Lett. 2003, 5, 2413.
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Supplementary data
36. Guilard, R.; Gros, C. P.; Barbe, J.-M.; Espinosa, E.; Jerome, F.; Tabard, A.; Latour,
J.-M.; Shao, J.; Ou, Z.; Kadish, K. M. Inorg. Chem. 2004, 43, 7441.
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Supplementary data associated with this article can be found in
the online version at doi:10.1016/j.tet.2011.04.024.
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