Iridium-catalyzed annulative coupling of 2-arylbenzoyl chlorides with alkynes: Selective formation of phenanthrene derivatives

Article abstract of DOI:10.1021/jo501835u

2-Arylbenzoyl chlorides undergo annulative coupling with internal alkynes in the presence of a catalyst system of [IrCl(cod)]₂/P(t-Bu)₃ to selectively afford the corresponding phenanthrene derivatives accompanied by elimination of carbon monoxide and hydrogen chloride. The reaction occurs without addition of any external base. Deuterium-labeling experiments using 2-(d₅-phenyl)benzoyl chloride suggest that the rate-determining step does not involve the C2′-H bond cleavage. Formation of a [(t-Bu)₃PH][(biphenyl-2,2′-diyl)Ir(CO)Cl₂] complex dimer, of which the structure was determined by single-crystal X-ray analysis, from a stoichiometric reaction at 60 °C without addition of alkyne also supports the facile C-H cleavage.

Full text of DOI:10.1021/jo501835u

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Featured Article
Iridium-Catalyzed Annulative Coupling of 2-Arylbenzoyl Chlorides
with Alkynes: Selective Formation of Phenanthrene Derivatives
Tomoya Nagata, Koji Hirano, Tetsuya Satoh, and Masahiro Miura
J. Org. Chem., Just Accepted Manuscript • Publication Date (Web): 13 Sep 2014
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Iridium-Catalyzed Annulative Coupling of
2-Arylbenzoyl Chlorides with Alkynes: Selective
Formation of Phenanthrene Derivatives
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Tomoya Nagata, Koji Hirano, Tetsuya Satoh, and Masahiro Miura*
Department of Applied Chemistry, Faculty of Engineering, Osaka University, Suita, Osaka
565-0871, Japan
miura@chem.eng.osaka-u.ac.jp
Cl
O
H
R
R
X
Y
[IrCl(cod)]2 (1 mol%)
P(t-Bu)3 (2 mol%)
+
X
Y
o-xylene, reflux
R
R
no base
ABSTRACT: 2-Arylbenzoyl chlorides undergo annulative coupling with internal alkynes in the
presence of a catalyst system of [IrCl(cod)]2/P(t-Bu)3 to selectively afford the corresponding
phenanthrene derivatives accompanied by elimination of carbon monoxide and hydrogen chloride.
The reaction occurs without addition of any external base. Deuterium labeling experiments using
2-(d5-phenyl)benzoyl chloride suggest that the rate-determining step does not involve the C2’-H
bond cleavage. Formation of a [(t-Bu)3PH][(biphenyl-2,2’-diyl)Ir(CO)Cl2] complex dimer, of which
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structure was determined by single-crystal X-ray analysis, from a stoichiometric reaction at 60 C
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without adding alkyne also supports the facile C-H cleavage.
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INTRODUCTION
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The chemistry of polycyclic aromatic hydrocarbons (PAHs) has a long history1 and they have
become increasingly important in recent years as the structural cores of various π-conjugated
functional materials.2 Thus, the selective synthesis of substituted PAHs even more attracts attention.
Among potential and straightforward strategies to construct condensed aromatics is the transition
metal-catalyzed benzannulation of aromatic substrates with alkynes. For instance, the reaction of
mono-functionalized benzenes and 2-functionalized naphthalenes with two alkyne molecules via
ortho-C-H bond cleavage directly provides multiply substituted naphthalenes and anthracenes,
respectively (Scheme 1a).3 Using aliphatic alkynes may produce the compounds having substantial
solubilities. Meanwhile, the annulation reaction of 2-functionalized 1,1’-biphenyls with an alkyne
through the activation of C2’-H bond appears to be a promising pathway for the synthesis of
phenanthrene series of compounds (Scheme 1b).4 This second type of coupling is, however, less
explored compared with the 1:2 coupling and still remains room for further development.
Scheme 1. Annulation of Mono-Functionalized Arenes with Alkynes
R
R
R
R
X
H
R
R
(a)
+
R
R
R
R
X
H
2'
3
(b)
+
R
R
As an early example of the phenanthrene formation (Scheme 1b), Heck reported the
palladium-catalyzed reaction of 2-iodobiphenyl (X = I) with diphenylacetylene albeit with a low
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yield.3d Larock described that the reaction is significantly promoted by the addition of sodium
acetate as base and various arylalkynes can be employed.4a Glorius demonstrated that
2-phenylbenzoic acids (X = COOH) can be used as the starting substrates in place of
2-iodobiphenyl in the palladium-catalyzed reaction using silver carbonate as oxidant and base.4b
Takahashi described the chromium-mediated reaction of 2-halo-1,1’-biphenyls.4c An iron-catalyzed
annulation of 1,1’-biphenyl-2-yl-magnesium bromide (X = MgBr) was reported by Nakamura.4d Wu
recently employed the Larock method (X = I) for the synthesis of [8]circulenes.4e
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We previously reported that benzoyl and naphthoyl chlorides effectively undergo 1:2 coupling
with alkynes in the presence of an iridium catalyst to afford the corresponding annulated products
accompanied by elimination of hydrogen chloride and carbon monoxide (Scheme 1a, X = COCl).3f, 5
It may be conceived that using a similar catalyst system, the reaction of 2-phenylbenzoyl chloride
leads to the corresponding phenanthrene (Scheme 1b, X = COCl). Indeed, we have found that the
annulation via C2’-H cleavage proceeds selectively without involving any 1:2 coupling via C3-H
cleavage. This reaction allows the use of dialkylacetylenes, which could not be employed in the
palladium-catalyzed reactions,4a,b while it was also possible in the case with 2,2’-diiodobiaryls as
substrates.4f,g It should also be noted that the reaction takes place without addition of any base as in
the reaction of simple benzoyl chloride. This implies that the C2’-H cleavage during the annulation
process can occur without assistance of an external base. Consequently, we have investigated the
phenanthrene formation reaction with respect to the substrate scope and undertaken
deuterium-labeling experiments using 2-(d5-phenyl)benzoyl chloride and isolation of an
intermediary complex from a stoichiometric reaction to provide mechanistic insights. The results
are described herein.
RESULTS AND DISCUSSION
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In an initial attempt, 2-phenylbenzoyl chloride (1a, 0.5 mmol) was treated with 4-octyne (2a,
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5
o
0.75 mmol) in the presence of [IrCl(cod)]2 (0.005 mmol) in refluxing o-xylene at 160 C (bath
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temperature) for 24 h under nitrogen and the expected 9,10-dipropylphenanthrene (3aa) was formed
in 61% GC yield (Table 1, entry 1). Then, the reaction was carried out with the addition of a
number of phosphine ligands. The use of PPh3 improved the yield of 3aa to 72% (entry 2) and
PPhCy2 gave an excellent yield of 97% within 9 h (entry 3). However, related more bulky P(Ar)Cy2
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type
phosphines,
P(o-tolyl)Cy2,
Ruphos
Xphos
(2-dicyclhexycylphosphino-2',6'-diisopropoxy-1,1'-biphenyl),
and
(2-dicyclohexylphosphino-2',4',6'-triisopropyl-1,1’-biphenyl) were less effective (entries 4-6).
While the reaction with Johnphos (2-(di-tert-butylphosphino)-1,1’-biphenyl) was sluggish (entry 7),
P(t-Bu)3 was found to be superior to PPhCy2 and afforded 3aa quantitatively within 3 h (entry 8,
83% after chromatographic purification). The use of [RhCl(cod)]2/P(t-Bu)3 in place of [IrCl(cod)]2
gave only a moderate yield of 3aa (entry 9). It is noted that in the absence of the alkyne 2a,
fluorenone (4a) was formed in 78% (24 h), whereas the formation of 4a was not observed at all in
the presence of 2a.
Table 1. Reaction of 2-Phenylbenzoyl Chloride (1a) with 4-Octyne (2a)a
COCl
n-C3H7
n-C3H7
[IrCl(cod)]2 (1 mol%)
ligand (2 mol%)
1a
+
o-xylene, 160 oC
n-C3H7
n-C3H7
3aa
2a (1.5 equiv)
entry
ligand
-
time (h)
Yield of 3aa (%)b
1
2
3
4
24
9
(61)
(72)
(97)
(18)
PPh3
PPhCy2
P(o-tolyl)Cy2
9
6
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Ruphos
Xphos
Johnphos
P(t-Bu)3
P(t-Bu)3
-
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9
(40)
(24)
7
9
(23)
8
3
83 (>98)
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9c
10d
24
3
88 (>98)
a Reaction conditions: 1a (0.50 mmol), 2a (0.75 mmol), [IrCl(cod)]2 (0.005 mmol), ligand (0.010
b
mmol), o-xylene (2.5 mL), under N2.
1-methylnaphthalene as internal standard.
Yield in parentheses was determined by GC with
c
d
Reaction with [RhCl(cod)]2 in place of [IrCl(cod)]2.
Reaction with complex 6 (0.005 mmol) as catalyst.
We next carried out the annulation reactions using a number of 2-arylbenzoyl chlorides and
alkynes under the conditions employed for entry 8 in Table 1 (Scheme 2). The reactions of 1a with
6-dodecyne (2b), 8-hexadecyne (2c), 1-phenyl-1-hexyne (2d), and diphenylacetylene (2e) gave the
corresponding 9,10-disubstituted phenanthrenes 3ab-3ae, with good yields, as in the case with 2a.
4,4’-Dimethoxy-, dimethyl-, dichloro-, and di(trifluoromethyl)-substituted diphenylacetylenes 2f-2i
also coupled with 1a to give 9,10-diarylphenanthrenes 3af-3ai. It is noted that while these products
were formed more than 90% GC yields with the exception of 3ai (ca. 60%), their lower yields are
attributable to the isolation process by recrystallization to eliminate the residual acetylenes. The
reaction of 1,2-bis(2-thienyl)acetylene (2j) with 1a afforded 9,10-di(2-thienyl)phenanthrene (3aj) in
excellent yield. Functionalized internal alkynes, ethyl 3-phenylpropynoate (2k) and
[2-(trimethylsilyl)ethynyl]benzene (2l), and even terminal alkynes, 1-octyne (2m) and
ethynylbenzene (2n), could also couple with 1a to provide phenanthrenes 3ak-3an, albeit in
moderate yields. 4’-Methyl-, 4’-fluoro-, and 4’-trifluoromethyl-substituted 2-phenylbenzoyl
chlorides 1b-1d also reacted with 2a to selectively produce phenanthrenes 3ba, 3ca, and 3da. In
contrast, the reaction of 2-(4’-methoxyphenyl)benzoyl chloride (1e) with 2a gave the expected 3ea
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along with 2-methoxyfluorenone (4e). The reaction of 2-(2-naphthyl)benzoyl chloride (1f) with 2a
similarly gave tetraphene 3fa (an isomer was accompanied: 3fa/isomer = 92:8, judged by 1H NMR)
and benzofluorenone 4f. Note that 3fa and 4f are formed by the cleavage of C3’-H and C1’-H
bonds, respectively. 4,4’-Dibromo-substituted 2-phenylbenzoyl chloride 1g effectively underwent
coupling with alkynes 3a and 3c to give 2,7-dibromo-9,10-dialkylphenanthrenes 3ga and 3gc in
good yields, demonstrating that bromo functions that can be used further transformations are
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tolerable
under
the
reaction
conditions.
It
is
worth
citing
that
2,7-dibromo-9,10-dialkylphenanthrenes are useful building blocks for the synthesis of π-conjugated
polymers.6 The reaction of 2-(3-methylphenyl)benzoyl chloride (1h) reacted with 2a to selectively
afford the corresponding 3,9,10-trisubstituted phenanthrene 3ha.
Scheme 2. Reaction of Various 2-Phenylbenzoyl Chlorides 1 with Alkynes 2a
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R1
R2
[IrCl(cod)]2 (1 mol%)
P(t-Bu)3 (2 mol%)
COCl
R1
2 (1.5 equiv)
R2
+
X
Y
X
Y
o-xylene, 160 oC
3
1
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n-C5H11 n-C5H11
n-C4H9
n-C7H15 n-C7H15
3ab, 94%
3ad, 90%
3ac, 85%
3ae, 73%
Me
Me
F3C
CF3
MeO
OMe
Cl
Cl
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3af, 50%b
3ah, 50%b
3ag, 54%
3ai, 23%c
S
S
CO2Et
SiMe3
n-C6H13
3aj, 96%d
3ak, 38%c
3al, 37%
3am, 45%
n-C3H7
n-C3H7
n-C3H7
n-C3H7
n-C3H7
n-C3H7
Me
CF3
F
3da, 84%
3an, 26%e
n-C3H7
3ca, 77%
3ba, 80%
O
n-C3H7
n-C3H7
n-C3H7
O
OMe
+
+
OMe
4e, 24%
3fa, 22%f
3ea, 38%
n-C3H7
4f, 70%
n-C3H7
n-C7H15 n-C7H15
n-C3H7
n-C3H7
Br
Br
Br
Br
3ha, 81%g
3gc, 84%
Me
3ga, 88%
a
Reaction conditions: 1 (0.50 mmol), 2 (0.75 mmol), [IrCl(cod)]2 (0.005 mmol), P(t-Bu)3 (0.010
mmol), o-xylene (2.5 mL), under N2 for 3 h. b Reaction for 4 h. c Reaction for 5 h. d Reaction for 6 h.
e
f
Reaction for 22 h. An isomer was contaminated (3fa/isomer = 92:8). Reaction with 0.42 mmol
g
of 1h and 0.63 mmol of 2a.
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On the basis of literature information and our findings, we are tempted to assume the mechanism
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for the reaction of 1 with 2 as depicted in Scheme 3, in which neutral ligands are omitted.
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Scheme 3. Plausible Mechanism
R
R
COCl
[IrCl(cod)]2/P(t-Bu)3
1
3
IrCl
- IrCl
Cl
R
R
O
R
IrCl2
C
IrCl2
Ir
R
H
- HCl
3
2'
R
A
E
C
- CO
2
R
R
R
(a)
(b)
Cl
R
Cl
Ir
Cl
Ir
Cl Ir H
2
2'
R
- HCl
B
F
D
R
R
R
R
2
R
R
R
Cl
Ir
R
C
-IrCl
-HCl
not observed
Oxidative addition of 1 to chloroiridium(I) gives aroyliridium(III) A, which undergoes
decarbonylation to give aryliridium(III) B.3f, 4c, 7 Then, there may be two pathways. (a) Insertion of
alkyne 2 to B gives vinyliridium C and the subsequent iridation via cleavage of C2’-H bond yields
seven-membered iridacycle E. (b) Alternatively, five-membered iridacycle D is formed before the
insertion of 2. In this case, the insertion occurs at both C2-Ir and C2’-Ir bonds to yield iridacycles E
and F. Anyway, reductive elimination at E or E/F affords product 3.4j, 8
To provide further mechanistic information, we carried out deuterium labeling experiments
using 2-(d5-phenyl)benzoyl chloride (1a-d5) (Scheme 4). When the reaction of 1a-d5 with 2a at 140
oC was stopped at 18 min and methanol was added, phenanthrene 3aa-d4 was formed together with
1
methyl 2-(d5-phenyl)benzoate (5a-d5) (eq 1). H NMR analysis of the isolated 3aa-d4 and 5a-d5
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indicated that no D-H exchange took place. The reaction of 1a-d5 with the unsymmetrical alkyne 2d
gave a 1:1 mixture of the corresponding phenanthrenes 3ad-d4 and 3ad-d4’ (eq 2). As such an
insertion of alkyl(aryl)acetylene to aryl-metal bond usually occurs regioselectively to a greater or
less extent,9 this implies that pathway (b) in Scheme 3 leading to the 1:1 product mixture is
predominantly involved in the catalytic cycle. No observation of 1:2 coupling product via pathway
(a) followed by iridation at C3, which corresponds to Scheme 1a, is consistent with the
consideration. This is in marked contrast to the related palladium catalysis with 2-phenylbenzoic
acids as substrates, in which preference for pathway (a)-type insertion was suggested.4b The
precedence of pathway (b) may be attributed to the facile C2’-H bond cleavage under the present
conditions. In connection with this, we carried out the competitive experiment with a 1:1 mixture of
1a and 1a-d5 together with 2a. The reaction proceeded even at 120 oC and gave a 1:1 mixture of 3aa
and 3aa-d4 at an early stage, suggesting that 1a and 1a-d5 equally reacted. While the
rate-determining step of the present catalytic cycle is not definitive at this stage, the observation
leads us to deduce that it does not involve the C2’-H cleavage, which occurs without addition of
any external base. This contrasts with the fact that in recently developed various Rh(III)-catalyzed
direct coupling reactions of arenes with unsaturated compounds through C-H bond cleavage, the
presence of a carboxylate species is usually required and substantial kH/kD values are often
observed.9,10
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Scheme 4. Deuterium-Labeling Experiments
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2
COOMe
3
4
COCl
1. [IrCl(cod)]2 (1 mol%)
P(t-Bu)3 ( 2 mol%)
5
6
7
8
D5
5a-d5, 46%
o-xylene
140 oC, 18 min
D5
1a-d5
+
n-C3H7
n-C3H7
(1)
+
2.
MeOH
9
n-C3H7
n-C3H7
rt, 10 min
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2a (1.5 equiv)
D4
3aa-d4, 50%
n-C4H9
COCl
3ad-d4
D4
[IrCl(cod)]2 (1 mol%)
P(t-Bu)3 ( 2 mol%)
1a-d5
D5
+
+
(2)
n-C4H9
o-xylene
160 oC, 3 h
n-C4H9
2d (1.5 equiv)
D4
3ad-d4'
91% (1:1)
n-C3H7 n-C3H7
1a (0.25 mmol)
+
3aa
[IrCl(cod)]2 (1 mol%)
P(t-Bu)3 ( 2 mol%)
+
n-C3H7
n-C3H7
1a-d5 (0.25 mmol)
(3)
o-xylene
120 oC, 1 h
+
2a (0.75 mmol)
D4
3aa-d4
19% (1:1)
We also carried out the stoichiometric reaction of 1a, [IrCl(cod)]2, and P(t-Bu)3 without adding
alkyne as depicted in Scheme 5. The reaction at 60 oC for 12 h gave an off-white solid. Dissolving it
in dichloromethane and gradual evaporation of the solvent afforded a sample suitable for
single-crystal X-ray analysis. Interestingly, it was found to be the dianionic iridium dimer complex
6 with the cation part of [(t-Bu)3PH]22+ (Figure 1). Its FT-IR spectrum showed two characteristic
bands at 2345 (P-H) and 2019 (C=O) cm-1 as expected. It was confirmed that the FT-IR spectra
before and after recrystallization are identical. The complex 6 may be considered as a [(t-Bu)3PH]Cl
adduct to the assumed intermediate D. Importantly, the reaction of 1a with 2a using 6 (1 mol%) as
catalyst efficiently proceeded as in the case using [IrCl(cod)]2/P(t-Bu)3 (Table 1, entry 10). The
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formation of 6 in the stoichiometric reaction may imply that the C2’-H cleavage that occurs even at
60 oC is likely promoted by (t-Bu)3P as an internal base. It should be noted that the 31P{1H} NMR of
CD2Cl2 solution of 6 unexpectedly showed two peaks at 50.14 and -13.96 ppm, which are
assignable to (t-Bu)3PH and (t-Bu)3PIr species, respectively.11 In accordance with this, the 1H NMR
of CD2Cl2 solution of 6 exhibited two doublets of t-Bu hydrogens coupled with the P atoms (J = 16
Hz) (see the Supporting Information). These NMR spectra may suggest that the complex 6 is in
equilibrium with a (t-Bu)3PIr species in CD2Cl2, while its exact structure is not definitive. Based on
these results, it may be reasonable to consider that (t-Bu)3P acts as both the internal base and ligand
during the reaction.11
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Scheme 5. Formation of Complex 6
COCl
[IrCl(cod)]2
0.1 mmol
P(t-Bu)3
+
+
1a
0.6 mmol
0.2 mmol
1. o-xylene, 60 oC, 12 h
2. recrystallization
from CH2Cl2
2-
2+
[(t-Bu)3PH]2
CO
Cl
Cl
Cl
Ir
Ir
Cl
CO
6, 58%
(X-ray structure of 2 units)
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Meanwhile, the competitive formation of fluorenones 4e and 4f together with 3ea and 3fa,
respectively, may be rationalized by the mechanism that involves either intramolecular iridation at
intermediary aroyliridium A or reinsertion of carbon monoxide at iridacycle D. It was confirmed
that both 1e and 1f did not give the fluorenones without adding the iridium catalyst under otherwise
identical conditions. The fact that the formation of the fluorenones in the presence of alkyne 2a was
observed only in the case of the electron-rich substrates 1e and 1f may imply the competitive
participation of iridation at aroyliridium A. The observation that in the reaction of 1f, 3fa and 4f are
formed through C-H cleavage on the different carbons, less hindered C3’ for 3fa and hindered but
relatively more electron-rich C1’ for 4f, respectively, appears to be in harmony with the
assumption.
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In summary, we have demonstrated that 2-arylbenzoyl chlorides effectively undergoes
annulative coupling on treatment with both aliphatic and aromatic internal alkynes in the presence
of a catalyst system of [IrCl(cod)]2/P(t-Bu)3 to selectively give the corresponding phenanthrene
derivatives. The reaction occurs without adding any external base and one of the major factors to
this success may be attributed to the facile intramolecular iridation via C-H bond cleavage
promoted by the phosphine ligand.
Experimental Section
Instrumentation and Chemicals. 1H and 13C NMR spectra were recorded at 400 and 100 MHz,
respectively, for CDCl3 solutions. HRMS data were obtained by APCI using a TOF unless
otherwise noted. GC analysis was carried out using a silicon OV-17 column (i.d. 2.6 mm x 1.5 m)
or a CBP-1 capillary column (i.d. 0.5 mm x 25 m). Materials obtained from commercial suppliers
were used without further purification. Acid chloride 1a was prepared by the reaction of
commercially available 1,1’-biphenyl-2-carboxylic acid with oxalyl chloride in the presence of
o
DMF at 0 C in dichloromethane according to the published procedure.12 The carboxylic acids for
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the preparation of acid chlorides 1b-1f, 1h, and 1a-d5 were synthesized by the nickel-catalyzed
Suzuki-Miyaura type coupling of methyl 2-iodobenzoate with the corresponding arylboronic acids
followed by hydrolysis with potassium hydroxide in aqueous ethanol.13 All the 2-arylbenzoic acids
(aryl = 4-MeC6H4,14 4-FC6H4,15 4-CF3C6H4,16 4-MeOC6H4,4b 2-naphthyl,4b 3-MeC6H4,4b and C6D54b)
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are
known.
4,4’-Dibromo-1,1’-biphenyl-2-carboxylic
acid
was
prepared
from
2,7-dibromofluorenone by the published procedure.17 The carboxylic acids were treated with oxalyl
chloride as for the chlorination of 1,1’-biphenyl-2-carboxylic acid12 to give 1b-1h and 1a-d5. The
purity of the acid chlorides was confirmed by 1H and 13C NMR.
2-Phenylbenzoyl chloride (1a): colorless oil;12 1H NMR (400 MHz, CDCl3) δ 7.30-7.53 (m,
7H), 7.63 (dt, J = 7.6, 1.3 Hz, 1H), 8.03 (dd, J = 7.9, 1.1 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3)
δ 127.6, 128.1, 128.6, 128.8, 131.2, 131.4, 133.2, 134.6, 139.8, 142.9, 168.5.
2-(4-Methylphenyl)benzoyl chloride (1b):18 colorless oil; H NMR (400 MHz, CDCl3) δ
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2.41 (s, 3H), 7.23-7.27 (m, 4H), 7.41 (dd, J = 7.7, 0.9 Hz, 1H), 7.47 (dt, J = 7.7, 1.3 Hz, 1H), 7.61
(dt, J = 7.6, 1.4 Hz, 1H), 8.00 (dd, J = 7.9, 1.3 Hz, 1H); C{1H} NMR (100 MHz, CDCl3) δ 21.4,
13
127.3, 128.7, 129.4, 131.1, 131.4, 133.2, 134.7, 136.9, 138.0, 142.8, 168.6.
2-(4-Fluorophenyl)benzoyl chloride (1c):19 orange oil; H NMR (400 MHz, CDCl3) δ
1
7.08-7.16 (m, 2H), 7.27-7.33 (m, 2H), 7.38 (dd, J = 7.7, 1.4 Hz, 1H), 7.50 (dt, J = 7.7, 1.2 Hz, 1H),
7.63 (dt, J = 7.6, 1.4 Hz, 1H), 8.04 (dd, J = 7.9, 1.1 Hz, 1H); C{1H} NMR (100 MHz, CDCl3)
13
δ 115.6 (d, J = 21.1 Hz), 127.8, 130.5 (d, J = 8.3 Hz), 131.4, 131.5, 133.4, 134.5, 135.8 (d, J = 3.6
Hz), 141.9, 162.8 (d, J = 245.9 Hz), 168.4.
2-(4-Trifluoromethylphenyl)benzoyl chloride (1d):20 colorless oil; H NMR (400 MHz,
1
CDCl3) δ 7.38 (dd, J = 7.6, 0.9 Hz, 1H), 7.44 (d, J = 8.0 Hz, 2H), 7.56 (dt, J = 7.7, 1.2 Hz, 1H),
7.64-7.72 (m, 3H), 8.12 (dd, J = 7.9, 1.1 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) δ 124.2 (q, J =
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269.0 Hz), 125.5 (q, J = 3.7 Hz), 128.4, 129.2, 130.2 (q, J = 32.5 Hz), 131.3, 131.9, 133.6, 134.1,
4
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141.7, 143.6, 168.2.
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2-(4-Methoxyphenyl)benzoylchloride (1e):21 colorless oil; 1H NMR (400 MHz, CDCl3) δ 3.86
(s, 3H), 6.94-7.00 (m, 2H), 7.25-7.30 (m, 2H), 7.40 (dd, J = 7.7, 0.9 Hz, 1H), 7.45 (dt, J = 7.7, 1.3
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Hz, 1H), 7.60 (dt, J = 7.6, 1.4 Hz, 1H), 7.98 (dd, J = 7.9, 1.0 Hz, 1H); C{1H} NMR (100 MHz,
13
CDCl3) δ 55.4, 114.1, 127.2, 130.1, 131.1, 131.4, 132.1, 133.1, 134.6, 142.4, 159.7, 168.8.
1
2-(2-Naphtyl)benzoyl chloride (1f):22 yellow oil; H NMR (400 MHz, CDCl3) δ 7.45 (dd, J =
8.4, 1.7 Hz, 1H), 7.49-7.56 (m, 4H), 7.63-7.69 (m, 1H), 7.82 (s, 1H), 7.85-7.93 (m, 3H), 8.08 (d, J =
7.9 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) δ 126.57, 126.61, 127.0, 127.7, 127.8, 127.9, 128.2,
128.3, 131.5, 131.7, 132.9, 133.3, 133.4, 134.6, 137.4, 142.9, 168.5.
1
4,4’-Dibromobiphenyl-2-carboxylic acid:17 white solid, mp 212 °C; H NMR (400 MHz,
(CH3)2SO) δ 7.25-7.30 (m, 2H), 7.33 (d, J = 8.3 Hz, 1H), 7.57-7.63 (m, 2H), 7.78 (dd, J = 8.2, 2.2
Hz, 1H), 8.90 (d, J = 2.1 Hz, 1H), 13.20 (s, 1H); C{1H} NMR (100 MHz, (CH3)2SO) δ 120.7,
13
121.0, 130.4, 131.1, 131.7, 132.5, 133.8, 133.9, 138.98, 139.03, 167.7.
1
4,4’-Dibromobiphenyl-2-carbonyl chloride (1g): pale yellow solid; mp 82-83 °C; H NMR
(400 MHz, CDCl3) δ 7.15-7.21 (m, 2H), 7.27-7.29 (s, 1H), 7.55-7.61 (m, 2H), 7.77 (dd, J = 8.2, 2.1
Hz, 1H), 8.16 (d, J = 2.0 Hz, 1H); C{1H} NMR (100 MHz, CDCl3) δ 121.9, 122.9, 130.3, 132.0,
13
132.7, 133.9, 135.8, 136.3, 137.6, 140.3, 167.2; HRMS (EI) m/z calcd for C13H7Br2ClO (M+)
371.8552, found 371.8551.
2-(3-Metylphenyl)benzoyl chloride (1h):4b colorless oil; 1H NMR (400 MHz, CDCl3) δ 2.41 (s,
3H), 7.11-7.19 (m, 2H), 7.20-7.25 (m, 1H), 7.32 (dd, J = 7.5, 7.5 Hz, 1H), 7.41 (dd, J = 7.7, 1.2 Hz,
1H), 7.48 (ddd, J = 7.7, 7.7, 1.3 Hz, 1H), 7.61 (ddd, J = 7.6, 7.6, 1.3 Hz, 1H), 8.01 (dd, J = 7.9, 1.3
Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) δ 21.6, 126.0, 127.5, 128.5, 128.9, 129.5, 131.1, 131.4,
133.1, 134.6, 138.3, 139.8, 143.0, 168.5.
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Typical Procedure for Reaction of 1 with 2. The synthesis of 3aa is representative: in a 20 mL
two-necked flask were placed [IrCl(cod)]2 (3.4 mg, 0.005 mmol) and P(t-Bu)3 (2 mg, 0.01 mmol) in
o-xylene (0.1 mL). The central neck of the flask was equipped with a reflux condenser having an N2
balloon connected by a three-way cock at its top and a rubber cap was inserted to the side-neck. The
flask was evacuated and filled with nitrogen (three times). A solution of acid chloride 1a (108.3 mg,
0.5 mmol) and alkyne 2a (82.7 mg, 0.75 mmol) in o-xylene (2.4 mL) was injected and the resulting
mixture was heated at 160 oC (bath temperature) with stirring for 3 h. After cooling, the solvent was
evaporated and the residue was fractionated by column chromatography on silica gel. Elution with
hexane gave phenanthrene 3aa (109 mg, 83%).
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9,10-Dipropylphenanthrene (3aa):4j white solid; mp 97-98 °C; 1H NMR (400 MHz, CDCl3) δ
1.18 (t, J = 7.4 Hz, 6H), 1.72-1.83 (m, 4H), 3.12-3.19 (m, 4H), 7.58-7.66 (m, 4H), 8.09-8.15 (m,
2H), 8.70-8.78 (m, 2H); C{1H} NMR (100 MHz, CDCl3) δ 15.0, 24.2, 31.7, 123.1, 124.9, 125.5,
13
126.7, 130.0, 131.5, 134.0; HRMS m/z calcd for C20H23 (M+H+) 263.1794, found 263.1794.
9,10-Dipentylphenanthrene (3ab):23 purified by column chromatography with hexane as
eluent (149 mg, 94%); white solid; mp 58-59 °C; 1H NMR (400 MHz, CDCl3) δ 0.99 (t, J = 7.2 Hz,
6H), 1.42-1.52 (m, 4H), 1.53-1.63 (m, 4H), 1.68-1.80 (m, 4H), 3.10-3.20 (m, 4H), 7.57-7.66 (m,
4H), 8.09-8.15 (m, 2H), 8.70-8.76 (m, 2H); C{1H} NMR (100 MHz, CDCl3) δ 14.3, 22.8, 29.5,
13
30.6, 32.8, 123.1, 124.8, 125.5, 126.7, 130.0, 131.5, 134.1; HRMS m/z calcd for C24H31 (M+H+)
319.2420, found 319.2420.
9,10-Diheptylphenanthrene (3ac): purified by column chromatography with hexane as eluent;
1
white solid (159 mg, 85%); mp 33-34 °C; H NMR (400 MHz, CDCl3) δ 0.95 (t, J = 6.9 Hz, 6H),
1.33-1.50 (m, 12H), 1.55-1.65 (m, 4H), 1.70-1.80 (m, 4H), 3.13-3.20 (m, 4H), 7.58-7.67 (m, 4H),
8.10-8.16 (m, 2H), 8.71-8.77 (m, 2H); C{1H} NMR (100 MHz, CDCl3) δ 14.3, 22.9, 29.4, 29.5,
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30.6, 30.9, 32.1, 123.1, 124.8, 125.5, 126.7, 130.0, 131.5, 134.1; HRMS m/z calcd for C28H39
4
5
(M+H+) 375.3046, found 375.3041.
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9-Butyl-10-phenylphenanthrene (3ad): purified by column chromatography with hexane as
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1
eluent (140 mg, 90%); white solid; mp 119-120 °C; H NMR (400 MHz, CDCl3) δ 0.82 (t, J = 7.4
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Hz, 3H), 1.31 (sextuplet, J = 7.4 Hz, 2H), 1.56-1.65 (m, 2H), 2.82-2.89 (m, 2H), 7.30-7.35 (m, 3H),
7.39-7.61 (m, 5H), 7.65-7.71 (m, 2H), 8.14-8.20 (m, 1H), 8.70-8.76 (m, 1H), 8.77-8.83 (m, 1H);
13C{1H} NMR (100 MHz, CDCl3) δ 13.9, 23.3, 30.4, 33.2, 122.4, 123.2, 125.4, 125.8, 126.2, 126.5,
126.9, 127.2, 127.7, 128.5, 129.5, 130.4, 130.6, 131.1, 132.6, 135.0, 137.0, 140.7; HRMS m/z calcd
for C24H23 (M+H+) 311.1794, found 311.1794.
9,10-Diphenylphenanthrene (3ae):4i purified by column chromatography with hexane/ethyl
1
acetate (95:5, v/v) as eluent (120 mg, 73%); white solid; mp 238-239 °C; H NMR (400 MHz,
CDCl3) δ 7.12-7.27 (m, 10H), 7.45-7.51 (m, 2H), 7.53-7.59 (m, 2H), 7.63-7.70 (m, 2H), 8.81 (d, J =
8.3 Hz, 2H); C{1H} NMR (100 MHz, CDCl3) δ 122.6, 126.5, 126.6, 126.8, 127.7, 128.0, 130.1,
13
131.2, 132.0, 137.3, 139.7; HRMS m/z calcd for C26H19 (M+H+) 331.1481, found 331.1480.
9,10-Bis(4-methoxyphenyl)phenanthrene (3af):4i purified by recrystallization from toluene;
white solid (98 mg, 50%); mp 263-264 °C; 1H NMR (400 MHz, CDCl3) δ 3.81 (s, 6H), 6.80 (d, J =
8.8 Hz, 4H), 7.06 (d, J = 8.8 Hz, 4H), 7.48 (ddd, J = 8.1, 6.9, 1.2 Hz, 2H), 7.59 (dd, J = 8.3, 1.0 Hz,
2H), 7.65 (ddd, J = 8.3, 6.9, 1.4 Hz, 2H), 8.80 (d, J = 8.3 Hz, 2H); C{1H} NMR (100 MHz,
13
CDCl3) δ 55.3, 113.2, 122.6, 126.4, 126.7, 128.0, 130.1, 132.1, 132.2, 132.5, 137.3, 158.1; HRMS
m/z calcd for C28H23O2 (M+H+) 391.1693, found 391.1694.
9,10-Bis(4-methylphenyl)phenanthrene (3ag):4j purified by recrystallization from toluene;
1
white solid (97 mg, 54%); mp 246 °C; H NMR (400 MHz, CDCl3) δ 2.33 (s, 6H), 7.03-7.08 (m,
8H), 7.47 (ddd, J = 8.1, 6.8, 1.1 Hz, 2H), 7.56 (dd, J = 8.3, 1.3 Hz, 2H), 7.65 (ddd, J = 8.3, 6.8, 1.4
Hz, 2H), 8.80 (d, J = 8.2 Hz, 2H); C{1H} NMR (100 MHz, CDCl3) δ 21.4, 122.6, 126.4, 126.6,
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128.0, 128.5, 130.1, 131.0, 132.3, 135.9, 136.8, 137.3; HRMS m/z calcd for C28H23 (M+H+)
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359.1794, found 359.1791.
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1
preparative GPC (100 mg, 50%); white solid; mp 251-252 °C; H NMR (400 MHz, CDCl3) δ
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7.05-7.10 (m, 4H), 7.23-7.28 (m, 4H), 7.47-7.53 (m, 4H), 7.65-7.72 (m, 2H), 8.81 (d, J = 8.4 Hz,
2H); C{1H} NMR (100 MHz, CDCl3) δ 122.8, 126.9, 127.0, 127.7, 128.3, 130.2, 131.6, 132.4,
13
132.9, 136.3, 137.9; HRMS m/z calcd for C26H17Cl2 (M+H+) 399.0702, found 399.0714.
9,10-Bis(4-(trifluoromethyl)phenyl)phenanthrene (3ai): purified by recrystallization from
toluene (54 mg, 23%); white solid; mp 287-288 °C; 1H NMR (400 MHz, CDCl3) δ 7.28 (d, J = 8.0
Hz, 4H), 7.44 (d, J = 8.2 Hz, 2H), 7.49-7.57 (m, 6H), 7.72 (ddd, J = 8.3, 7.0, 1.2 Hz, 2H), 8.84 (d, J
= 8.2 Hz, 2H); 13C{1H} NMR (100 MHz, CDCl3) δ 122.9, 124.2 (q, J = 270.5 Hz), 125.0 (q, J = 3.7
Hz), 127.2, 127.6, 129.3 (q, J = 32.0 Hz), 130.3, 131.2, 131.4, 136.1, 143.1 (one peak is
overlapped); HRMS m/z calcd for C28H17F6 (M+H+) 467.1229, found 467.1230.
9,10-Di(thiophen-2-yl)phenanthrene (3aj):24 purified by column chromatography with
1
hexane/ethyl acetate (98:2, v/v) as eluent (164 mg, 96%); white solid; mp 245 °C; H NMR (400
MHz, CDCl3) δ 6.95 (dd, J = 3.4, 1.2 Hz, 2H), 7.02 (dd, J = 5.1, 3.4 Hz, 2H), 7.34 (dd, J = 5.1, 1.2
Hz, 2H), 7.55 (ddd, J = 8.2, 7.0, 1.2 Hz, 2H), 7.70 (ddd, J = 8.3, 7.0, 1.3 Hz, 2H), 7.81 (dd, J = 8.3,
1.0 Hz, 2H), 8.78 (d, J = 8.2 Hz, 2H); C{1H} NMR (100 MHz, CDCl3) δ 122.6, 126.3, 126.5,
13
127.1, 127.3, 128.0, 129.4, 130.4, 132.3, 132.4, 139.9; HRMS m/z calcd for C22H15S2 (M+) 343.0610,
found 343.0611.
Ethyl 10-phenylphenanthrene-9-carboxylate (3ak):25 purified by column chromatography
with hexane/ethyl acetate (95:5, v/v) as eluent and preparative GPC (62 mg, 38%); pale yellow
solid; mp 128-129 °C; 1H NMR (400 MHz, CDCl3) δ 0.97 (t, J = 7.1 Hz, 3H), 4.12 (q, J = 7.1 Hz,
2H), 7.42-7.55 (m, 6H), 7.62-7.75 (m, 4H), 7.94 (dd, J = 8.1, 1.3 Hz, 1H), 8.77 (d, J = 8.2 Hz, 2H);
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13C{1H} NMR (100 MHz, CDCl3) δ 13.9, 61.3, 122.8, 123.0, 126.0, 127.0, 127.2, 127.56, 127.59,
127.9, 128.1, 128.2, 130.1, 130.5, 130.77, 130.81, 131.0, 136.6, 138.2, 169.4; HRMS m/z calcd for
C23H19O2 (M+H+) 327.1380, found 327.1387.
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Trimethyl(9-phenylphenanthren-1-yl)silane (3al):4c purified by column chromatography with
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hexane as eluent and preparative GPC (60 mg, 37%); pale yellow solid; mp 161-162 °C; H NMR
(400 MHz, CDCl3) δ 0.29 (s, 9H), 5.96 (d, J = 8.0 Hz, 1H), 6.81 (ddd, J = 8.0, 7.4, 1.2 Hz, 1H),
7.05-7.11 (m, 2H), 7.18 (dt, J = 7.4, 1.0 Hz, 1H), 7.28-7.47 (m, 5H), 7.64 (d, J = 7.4 Hz, 1H), 7.72
(d, J = 7.4 Hz, 1H), 7.99 (d, J = 7.7 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) δ 0.6, 119.1, 119.5,
125.7, 126.16, 126.22, 126.55, 126.64, 126.9, 127.9, 128.2, 129.0, 138.6, 139.0, 140.6, 141.3, 145.2,
145.8, 149.4; HRMS m/z calcd for C23H23Si (M+H+) 327.1564, found 327.1570.
9-Hexylphenanthrene (3am):26 purified by column chromatography with hexane as eluent and
preparative GPC (59 mg, 45%); white solid; mp 77-78 °C; 1H NMR (400 MHz, CDCl3) δ 0.92 (t, J
= 7.1 Hz, 3H), 1.30-1.43 (m, 4H), 1.45-1.55 (m, 2H), 1.78-1.88 (m, 2H), 3.12 (t, J = 7.7 Hz, 2H),
7.55-7.70 (m, 5H), 7.81-7.87 (m, 1H), 8.09-8.16 (m, 1H), 8.63-8.70 (m, 1H), 8.71-8.79 (m, 1H);
13C{1H} NMR (100 MHz, CDCl3) δ 14.3, 22.8, 29.7, 30.4, 31.9, 33.6, 122.6, 123.3, 124.6, 126.0,
126.1, 126.2, 126.6, 126.7, 128.1, 129.7, 130.8, 131.5, 132.1, 137.2; HRMS m/z calcd for C20H23
(M+H+) 263.1794, found 263.1802.
9-Phenylphenanthrene (3an):25 purified by column chromatography with hexane as eluent and
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preparative GPC (32 mg, 25%); white solid; mp 104 °C; H NMR (400 MHz, CDCl3) δ 7.45-7.60
(m, 6H), 7.61-7.74 (m, 4H), 7.88-7.97 (m, 2H), 8.75 (dd, J = 8.1, 0.5 Hz, 1H), 8.80 (ddd, J = 8.3,
0.5, 0.5 Hz, 1H); C{1H} NMR (100 MHz, CDCl3) δ 122.7, 123.0, 126.58, 126.63, 126.7, 127.0,
13
127.1, 127.5, 127.6, 128.4, 128.8, 130.1, 130.2, 130.8, 131.3, 131.7, 138.9, 140.9; HRMS m/z calcd
for C20H15 (M+H+) 255.1168, found 255.1169.
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2-Methyl-9,10-dipropylphenanthrene (3ba): purified by column chromatography with hexane
as eluent (110 mg, 80%); white solid, mp 71-73 °C; 1H NMR (400 MHz, CDCl3) δ 1.20 (t, J = 7.3
Hz, 3H), 1.21 (t, J = 7.3 Hz, 3H), 1.73-1.85 (m, 4H), 2.63 (s, 3H), 3.12-3.20 (m, 4H), 7.45 (dd, J =
8.4, 1.4 Hz, 1H), 7.57-7.64 (m, 2H), 7.90 (s, 1H), 8.09-8.15 (m, 1H), 8.63 (d, J = 8.5 Hz, 1H),
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8.67-8.74 (m, 1H); C{1H} NMR (100 MHz, CDCl3) δ 15.0 (2C), 22.2, 24.1, 24.2, 31.6, 31.7,
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122.9, 123.0, 124.5, 124.8, 125.4, 126.2, 127.2, 127.8, 130.0, 131.1, 131.6, 133.7, 134.0, 136.2;
HRMS m/z calcd for C21H25 (M+H+) 277.1951, found 277.1950.
2-Fluoro-9,10-dipropylphenanthrene (3ca): purified by column chromatography with hexane
as eluent (108 mg, 77%); white solid, mp 88-89 °C; 1H NMR (400 MHz, CDCl3) δ 1.18 (t, J = 7.3
Hz, 3H), 1.19 (t, J = 7.4 Hz, 3H), 1.69-1.82 (m, 4H), 3.04-3.11 (m, 2H), 3.11-3.18 (m, 2H), 7.34
(ddd, J = 9.1, 7.8, 2.6 Hz, 1H), 7.58-7.65 (m, 2H), 7.73 (dd, J = 11.7, 2.6 Hz, 1H), 8.08-8.15 (m,
1H), 8.60-8.66 (m, 1H), 8.68 (dd, J = 9.2, 5.9 Hz, 1H); C{1H} NMR (100 MHz, CDCl3) δ 14.9,
13
15.0, 23.9, 24.1, 31.7, 31.8, 109.5 (d, J = 21.3 Hz), 114.3 (d, J = 23.4 Hz), 122.9, 125.0, 125.3 (d, J
= 8.8 Hz), 125.9, 126.5, 126.6, 129.7, 131.0, 133.2 (d, J = 8.0 Hz), 133.4 (d, J = 3.7 Hz), 135.4,
161.8 (d, J = 242.7 Hz); HRMS m/z calcd for C20H22F (M+H+) 281.1700, found 281.1693.
9,10-Dipropyl-2-(trifluoromethyl)phenanthrene (3da): purified by column chromatography
1
with hexane as eluent (139 mg, 84%); white solid, mp 106-107 °C; H NMR (400 MHz, CDCl3)
δ 1.18 (t, J = 7.4 Hz, 6H), 1.69-1.82 (m, 4H), 3.11-3.20 (m, 4H), 7.60-7.73 (m, 2H), 7.78 (dd, J =
8.7, 1.5 Hz, 1H), 8.14 (dd, J = 8.0, 1.3 Hz, 1H), 8.36 (s, 1H), 8.72 (dd, J = 8.0, 1.4 Hz, 1H), 8.80 (d,
J = 8.7 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) δ 14.86, 14.94, 24.1, 24.3, 31.5, 31.7, 121.3 (q, J
= 3.2 Hz), 122.2 (q, J = 4.3 Hz), 123.5, 123.9, 124.8 (q, J = 270.7 Hz) 125.1, 126.1, 127.8, 128.3 (q,
J = 31.8 Hz), 129.2, 131.0, 132.1, 132.2, 133.9, 135.7; HRMS m/z calcd for C21H22F3 (M+H+)
331.1668, found 331.1659.
2-Methoxy-9,10-dipropylphenanthrene (3ea): purified by column chromatography with
hexane/ethyl acetate (98:2, v/v) as eluent (55 mg, 38%); pale yellow solid, m.p. 64-66 °C; 1H NMR
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(400 MHz, CDCl3) δ 1.19 (t, J = 7.3 Hz, 3H), 1.19 (t, J = 7.3 Hz, 3H), 1.72-1.85 (m, 4H), 3.08-3.19
(m, 4H), 4.00 (s, 3H), 7.26 (dd, J = 9.1, 2.6 Hz, 1H), 7.51 (d, J = 2.6 Hz, 1H), 7.54-7.62 (m, 2H),
8.07-8.13 (m, 1H), 8.59-8.68 (m, 2H); 13C{1H} NMR (100 MHz, CDCl3) δ 14.97, 15.02, 23.8, 24.2,
31.75, 31.80, 55.5, 106.5, 114.8, 122.6, 124.3, 124.7, 124.9, 125.6, 125.7, 130.0, 130.4, 132.9,
133.4, 134.7, 158.4; HRMS m/z calcd for C21H25O (M+H+) 293.1900, found 293.1907.
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5,6-Dipropyltetraphene (3fa): purified by column chromatography with hexane/ethyl acetate
(98:2, v/v) as eluent (34 mg, 22%); pale yellow solid, mp 105-107 °C; 1H NMR (400 MHz, CDCl3)
δ 1.20 (t, J = 7.4 Hz, 3H), 1.23 (t, J = 7.3 Hz, 3H), 1.74-1.91 (m, 4H), 3.10-3.18 (m, 2H), 3.20-3.27
(m, 2H), 7.51-7.57 (m, 2H), 7.61-7.67 (m, 2H), 8.05-8.13 (m, 3H), 8.55 (s, 1H), 8.85-8.91 (m, 1H),
9.20 (s, 1H); C{1H} NMR (100 MHz, CDCl3) δ 14.99, 15.04, 23.94, 23.96, 31.8 (2C), 121.8,
13
123.26, 123.31, 125.0, 125.6, 125.7, 125.9, 127.2, 128.2, 128.3, 128.9, 130.27, 130.32, 131.2, 131.8,
132.2, 133.78, 133.84; HRMS m/z calcd for C24H25 (M+H+) 313.1951, found 313.1950.
2,7-Dibromo-9,10-dipropylphenanthrene (3ga): purified by column chromatography with
hexane as eluent (185 mg, 88%); white solid, mp 82-83 °C; 1H NMR (400 MHz, CDCl3) δ 1.16 (t, J
= 7.3 Hz, 6H), 1.65-1.77 (m, 4H), 3.02-3.09 (m, 4H), 7.66 (d, J = 8.7 Hz, 2H), 8.18 (d, J = 1.8 Hz,
2H), 8.47 (d, J = 8.8, 2H); 13C{1H} NMR (100 MHz, CDCl3) δ 14.9, 24.0, 31.6, 121.5, 124.7, 127.5,
128.2, 129.0, 133.0, 134.5; HRMS m/z calcd for C20H20Br2 (M+) 417.9932, found 417.9926.
2,7-Dibromo-9,10-diheptylphenanthrene (3gc): purified by column chromatography with
hexane as eluent (225 mg, 84%); white solid, mp 62- 64 °C; 1H NMR (400 MHz, CDCl3) δ 0.93 (t,
J = 6.9 Hz, 6H), 1.30-1.47 (m, 12H), 1.51-1.61 (m, 4H), 1.61-1.73 (m, 4H), 3.00-3.09 (m, 4H), 7.65
(dd, J = 8.8, 1.8 Hz, 2H), 8.18 (d, J = 1.9 Hz, 2H), 8.44 (d, J = 8.8 Hz, 2H); C{1H} NMR (100
13
MHz, CDCl3) δ 14.3, 22.9, 29.2, 29.4, 30.4, 30.7, 32.0, 121.5, 124.7, 127.5, 128.2, 128.9, 133.0,
134.6; HRMS m/z calcd for C28H36Br2 (M+) 530.1184, found 530.1187.
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3-Methyl-9,10-dipropylphenanthrene (3ha): purified by column chromatography with hexane
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as eluent (94 mg, 81%); colorless oil; H NMR (400 MHz, CDCl3) δ 1.18 (t, J = 7.3 Hz, 6H),
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1.71-1.84 (m, 4H), 2.63 (s, 3H), 3.10-3.19 (m, 4H), 7.46 (dd, J = 8.4, 1.2 Hz, 1H), 7.56-7.65 (m,
9
2H), 8.02 (d, J = 8.5 Hz, 1H), 8.08-8.14 (m, 1H), 8.53 (s, 1H), 8.70-8.77 (m, 1H); C{1H} NMR
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(100 MHz, CDCl3) δ 15.0, 22.0, 24.15, 24.20, 31.6, 31.7, 122.9, 123.0, 124.79, 124.84, 125.3, 126.5,
128.4, 129.4, 129.7, 130.0, 131.7, 133.0, 133.9, 135.0; HRMS m/z calcd for C21H25 (M+H+)
277.1951, found 277.1947.
2-Methoxy-9H-fluoren-9-one (4e):27 purified by column chromatography with hexane/ethyl
acetate (98:2, v/v) as eluent (25 mg, 24%); yellow solid, mp 74-76 °C; 1H NMR (400 MHz, CDCl3)
δ 3.85 (s, 3H), 6.97 (dd, J = 8.2, 2.4 Hz, 1H), 7.16-7.22 (m, 2H), 7.37-7.46 (m, 3H), 7.57-7.62 (m,
1H); C{1H} NMR (100 MHz, CDCl3) δ 55.9, 109.5, 119.7, 120.4, 121.5, 124.5, 128.0, 134.4,
13
135.0, 136.0, 137.1, 145.0, 161.0, 194.0; HRMS m/z calcd for (M+H+) 211.0754, found 211.0768.
11H-Benzo[α]fluoren-11-one (4f):28 purified by column chromatography with hexane/ethyl
1
acetate (98:2, v/v) as eluent (81 mg, 70%); orange solid, mp 130-132 °C; H NMR (400 MHz,
CDCl3) δ 7.21-7.28 (m, 1H), 7.37-7.46 (m, 3H), 7.54-7.61 (m, 3H), 7.75 (d, J = 8.3 Hz, 1H), 7.94
(d, J = 8.2 Hz, 1H), 8.93 (d, J = 8.4 Hz, 1H); C{1H} NMR (100 MHz, CDCl3) δ 118.2, 120.0,
13
123.9, 124.4, 126.5, 126.9, 128.6, 129.3, 129.5, 130.3, 134.3, 134.5, 134.7, 136.0, 144.0, 146.2,
195.5; HRMS m/z calcd for C17H11O (M+H+) 231.0804, found 231.0800.
Preparation of Complex 6. In a 20 mL two-necked flask were placed [IrCl(cod)]2 (67.2 mg,
0.1 mmol) and P(t-Bu)3 (40.5 mg, 0.2 mmol) in o-xylene (0.5 mL). The central neck of the flask
was equipped with a reflux condenser having an N2 balloon connected by a three-way cock at its
top and a rubber cap was inserted to the side-neck. The flask was evacuated and filled with nitrogen
(three times). A solution of acid chloride 1a (130 mg, 0.6 mmol) in o-xylene (1.5 mL) was injected
o
and the resulting mixture was heated at 60 C with stirring for 12 h. After cooling, the solvent was
evaporated and the residue was washed with diethyl ether and hexane to give an off-white solid
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(108 mg). Dissolving it in dichloromethane (ca. 15 mL) and gradual evaporation of the solvent
afforded the analytical sample of complex 6 (75 mg, 58%). The structure was confirmed by
single-crystal X-ray (Mo Kα) diffraction (Scheme 5 and the Supporting Information: CCDC
1018164). FT-IR (KBr): 2345, 2019 cm-1. Anal. Calcd for C50H72Cl4Ir2O2P2: C, 46.43; H, 5.61.
Found: C, 46.14; H, 5.47.
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ASSOCIATED CONTENT
Supporting Information
1H and 13C NMR spectra for compounds. This material is available free of charge via the Internet
at http://pubs.acs.org.
AUTHOR INFORMATION
Corresponding Author
*E-mail: miura@chem.eng.osaka-u.ac.jp
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
This work was supported by Grants-in-Aid for Scientific Research from the MEXT and JSPS, Japan.
We thank Dr. M. Ohashi of Osaka University for X-ray analysis and helpful discussion.
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