Synthesis of substituted phenanthrene by iron(III)-catalyzed intramolecular alkyne-carbonyl metathesis

Article abstract of DOI:10.1021/jo301371n

An efficient synthesis of functionalized phenanthrenes has been developed for the first time involving an iron(III)-catalyzed intramolecular coupling of 2′-alkynyl-biphenyl-2-carbaldehydes. A broad range of functionalized phenanthrene derivatives could be

Full text of DOI:10.1021/jo301371n

Note
pubs.acs.org/joc
Synthesis of Substituted Phenanthrene by Iron(III)-Catalyzed
Intramolecular Alkyne−Carbonyl Metathesis
Krishnendu Bera, Soumen Sarkar, Swapnadeep Jalal, and Umasish Jana*
Department of Chemistry, Jadavpur University, Kolkata-700 032, West Bengal, India
S
* Supporting Information
ABSTRACT: An efficient synthesis of functionalized phenanthrenes has been
developed for the first time involving an iron(III)-catalyzed intramolecular
coupling of 2′-alkynyl-biphenyl-2-carbaldehydes. A broad range of functionalized
phenanthrene derivatives could be obtained in the present method in moderate
to good yields with high chemo- and regioselectivity. This transformation can
also be applied to the synthesis of an angularly fused tetracyclic compound. This
method offers several advantages such as high selectivity, mild reaction
conditions, and easy availability of starting materials.
regioselective synthesis of functionalized phenanthrene still
he construction of phenanthrene skeleton has attracted
Tconsiderable attention due to their occurrence in remains as a highly desirable goal in organic synthesis.
numerous natural products.1 Compounds having this structural
The Wittig reaction and its variants are among the most
powerful strategies for the construction of carbon−carbon
double bonds in organic synthesis.13 With regard to this aspect,
very recently, alkyne−carbonyl metathesis, i.e., the addition of
C−O double bond to C−C triple bonds for the construction of
α,β-unsaturated carbonyl compounds, has been recognized as
an atom economical alternative to the Wittig reaction.14
Although this reaction seems to be very useful, but has been
less exploited and only introduced very recently in organic
synthesis. This alkyne−carbonyl metathesis is considered to be
proceeding via a [2 + 2] cycloaddition and cycloreversion
process in the presence of Lewis or strong Brønsted acids
(Scheme 1).
motif also exhibit interesting biological roles such as
antimalarial,2 anticancer,3 and emetic activity.4 Moreover, they
are also very useful in material science because of their
photoconductivity, photochemical and electroluminescent
properties.5 In addition, synthesis of phenanthrene motif is
the key step in the preparation of several phenanthrene based
alkaloids such as phenanthroindolizidine, phenanthroquinolizi-
dine, etc.6 Therefore, numerous synthetic methods have been
developed from time to time in order to improve the efficiency
of synthesis of phenanthrene skeleton. Among them, the
preparations of stilbene followed by aryl−aryl coupling
reactions are the most extensively studied approaches to afford
the phenanthrene skeleton. The aryl−aryl bonds are generally
formed using Pschorr reaction, photocyclization, radical and
other oxidative coupling reactions.7
Scheme 1. Intramolecular Alkyne−Carbonyl Metathesis
A second, frequently utilized strategy involves aryl−aryl
coupling followed by various intramolecular cyclization via aldol
condensation, McMurry coupling, ring closing alkene meta-
thesis and DDQ oxidation reactions to afford phenanthrene
molecules.8 Other strategies for the phenanthrene synthesis are
based on metal induced carbocylization of alkynylated biaryl
derivatives,9 and metal-catalyzed intramolecular [4 + 2]
cycloaddition of biaryl compounds with alkynes.10 Very
recently, the coupling of terminal alkynes with N-tosylhy-
drazones11 in the presence of CuBr2 (10 mol %), TBAB (20
mol %) and LiOtBu (4 equiv), and a three-component
carbocyclization of biphenyl-2-carbaldehydes/alkynes/piperi-
dine in the presence of Zn/CuI/TFA have also been reported
to achieve phenanthrene derivatives.12 Despite these advances,
some of the above said methods suffer from one or more
limitations such as low yields, poor regioselecivity, drastic
reaction conditions, use of expensive and large excess of toxic
reagents in most cases. Therefore, the development of new,
mild and environmentally friendly approaches for the
A delicate design of intramolecular version of this reaction
would allow the constructing of complex carbo- and
heterocyclic compounds from easily available starting materials.
Despite the potential of this reaction, only a few examples of
the intramolecular version of this reaction have been
reported.15 During our recent study in this area,15a we
envisaged that the phenanthrene skeleton could be synthesized
via intramolecular alkyne−carbonyl metathesis from a sub-
stituted 2′-alkynyl-biphenyl-2-carbaldehyde (Scheme 2). Here-
in, we report an efficient synthetic route to 9-acyl
phenanthrenes under mild conditions through the intra-
Received: July 6, 2012
Published: September 6, 2012
© 2012 American Chemical Society
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Note
a
Scheme 2. Design of Phenanthrene Synthesis by Alkyne−
Carbonyl Metathesis
Table 1. Optimization of Reaction Conditions
entry
catalyst (mol %)
time (h)
temperature
yield (%)
1
FeCl3 (5)
12
12
3
rt
nr
40
86
86
83
44
45
nr
2
FeCl3 (5)
60 °C
reflux
reflux
reflux
reflux
reflux
reflux
reflux
reflux
reflux
reflux
3
FeCl3 (5)
4
FeCl3(10)
FeCl3·6H2O (5)
FeBr3 (5)
3
5
5
molecular alkyne−carbonyl metathesis of 2′-alkynyl-biphenyl-2-
carbaldehyde in presence of catalytic amount of FeCl3.
The required substrate, 2′-alkynyl-biphenyl-2-carbaldehyde
1, has been prepared by a two-step transformation in high yield
starting from 1-bromo-2-iodobenzene 3 derivatives, as outlined
in Scheme 3. The Sonogashira coupling of 1-bromo-2-
6
6
7
Fe(OTf)3 (5)
Fe(acac)3 (5)
lnCl3 (5)
7
8
8
9
4
85
82
74
86
10
11
12
AgOTf(5)
AuCl3 (5)
TfOH (5)
6
6
4
a
Scheme 3. Preparation of 2′-Alkynyl-biphenyl-2-
Conditions: Substrate 1a (0.5 mmol), catalyst (0.025 mmol) and 1,2-
a
carbaldehydes
dichloroethane (3 mL).
(Table 1, entries 9−11). These results demonstrated that
anhydrous FeCl3 exhibited higher catalytic activity for this
particular transformation, with only 5 mol % required for
achieving high yield. Strong Brønsted acid such as TfOH
provided similar results (Table 1, entry 12); however, because
of the ease of operation and economical, sustainable, and
environmentally friendly nature of iron,16 we employed iron as
the catalyst for this transformation.
a
Reaction conditions: (i) Aryl/alkyl acetylene, BuNH2, Pd(PPh3)4,
CuI, THF. (ii) 2-Formyl phenylboronic acid, Pd(PPh3)4, K2CO3,
EtOH, toluene.
With these encouraging results in hand, this intramolecular
coupling strategy has been investigated using various
substituted 2′-alkynyl-biphenyl-2-carbaldehydes to synthesize
a diverse range of functionalized phenanthrenes under the
optimized reaction conditions. In terms of structural features,
first we explored the substituent effects on the biphenyl ring
attached to the alkyne motif of the starting material (Table 2).
iodobenzene with terminal alkynes followed by Suzuki−
Miyaura coupling with 2-formyl phenylboronic acid afforded
the desired starting materials in very high yield.
To explore the possibility of the alkyne−carbonyl metathesis
in biaryl system, we began our investigations using 2′-alkynyl-
biphenyl-2-carbaldehyde 1a to optimize the suitable conditions
with various catalysts. The results are summarized in Table 1.
In view of the high catalytic activity of FeCl3 for the alkyne−
carbonyl metathesis in our previous work and related work
reported by others,14g,15a,b we first examined the intramolecular
alkyne−aldeyhde coupling of 1a in the presence of anhydrous
FeCl3. The reaction did not procced with 5 mol % FeCl3 in 1,2-
dichloroethane at room temperature; however, heating to 60
°C for 12 h resulted in the formation of the desired
phenanthrene 2b in 40% yield (Table 1, entry 2). We were
delighted to find that the reaction temperature played a crucial
role for the efficiency of this reaction, and yield was
dramatically improved to 86% when the reaction mixture was
heated to reflux for 3 h in the presence of 5 mol % of anhydrous
FeCl3 (Table 1, entry 3). Further, increasing the temperature
and amount of catalyst loading from 5 to 10 mol % did not
have a beneficial effect. Other iron catalysts such as
FeCl3·6H2O, FeBr3 and Fe(OTf)3 were also investigated, and
they gave a lower yield of the desired product (Table 1, entries
5−7). Fe(acac)3 did not show any catalytic activity toward this
coupling reaction (Table 1, entry 8). We also screened other
solvents such as MeNO2, CH3CN, THF and toluene, but only
inferior results were obtained. In addition, other commonly
used Lewis acids such as InCl3, AgOTf and AuCl3 also
produced the desired product but failed to improve the yield
Table 2. Intramolecular Alkyne−Carbonyl Metathesis of a
a
Variety of Substituted Biphenyls
a
Conditions: Substrate (0.5 mmol), FeCl3 (0.025 mmol) and 1,2-
dichloroethane (3 mL).
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Note
To our delight, biaryls possessing electron-donating groups
such as −Me and −OMe or electron-withdrawing groups such
as −F, −Cl and −CO2Et were smoothly reacted under this
reaction conditions and gave the desired products 2b−2f in
good yields (68−79%).
Table 4. Intramolecular Coupling of Carbonyl with Aliphatic
Alkynes
a
Along these lines, it is notable that halide substituted
phenanthrene derivatives would be very useful substrates for
further synthetic transformations by transition metal catalyzed
cross-coupling reactions. Moreover, a benzene fused biaryl was
also efficiently converted to the desired angularly fused
tetracyclic compound 2g in high yield, 85% (Table 2). These
results further demonstrated the potential of the reaction for
the synthesis of a higher polycyclic aromatic hydrocarbon
(PAH).
We also investigated a variety of substituents in the aryl
alkyne moiety of 2′-alkynyl-biphenyl-2-carbaldehyde (Table 3).
a
Conditions: substrates (0.5 mmol),1,2-dichloroethane and FeCl3
b
c
Table 3. Iron-Catalyzed Synthesis of Substituted
(0.025 mmol). Reaction was performed at 60 °C. Performed in
MeNO2 solvents.
a
Phenanthrene
Scheme 4. Phenanthrene Synthesis with Coupling of Alkyne
and Ketone
entry
Ar
time (h)
yield of 2 (%)
1
2
3
4
p-Me-C6H4 1h
6
2h (57)
2i (83)
p-Cl-C6H4 1i
6
b
m-NO2-C6H4 2j
6-MeO-2-Naphthyl 2k
1.5
8
2j (77)
2k (56)
are 9-acyl phenanthrene derivatives, which are generally made
by Friedel−Crafts acylation of phenanthrenes. So, employing
this approach, the Friedel−Crafts acylation reaction could be
avoided to synthesize 9-acyl phenanthrene. Unfortunately,
terminal alkyne did not undergo this reaction. All of the
products were characterized by spectroscopic methods, and
product 2b (CCDC no. 881041) was further confirmed by X-
ray crystallography (see the Supporting Information).
On the basis of the above experimental results, a plausible
catalytic cycle is proposed to illustrate the formation of product
(Scheme 5). Presumably, the reaction may proceed through
formation of an oxetene intermediate 7 via an intramolecular [2
+ 2] cycloaddition, and a subsequent cycloreversion of oxetene
intermediate producing the product. The definite role of the
iron catalyst is not known; however, we believed that the
catalytic cycle begins with the coordination of FeCl3 to the
a
Conditions: Substrate 1 (0.5 mmol), FeCl3 (0.025 mmol) and 1,2-
dichloroethane (3 mL), Carried out at 60 °C.
b
Alkynes bearing an electron-donating group such as p-Me
(Table 3, entry 1) and electron-withdrawing groups such as p-
Cl and m-NO2 groups (Table 3, entries 2 and 3) were easily
converted to the desired phenanthrenes in good to high yields
(57−77%). Notably, 2-naphthyl bearing alkyne motif was also
applicable to this cyclization reaction to give the product 2k in
56% yield (Table 3, entry 4).
Next, we studied a few substrates possessing an alkyl group at
one of the terminus of biaryl alkynes to show the versatility of
this reaction (Table 4). Interestingly, this strategy was also
equally applicable to the internal alkynes bearing an alkyl group
such as 1l, 1m and 1n bearing an alkyl group affording the
desired phenanthrenes 2l, 2m and 2n in moderate yields as 64,
60, and 45%, respectively.
Finally, the intramolecular coupling of biphenyl possessing
an alkyne and a ketone group instead of an aldehyde has also
been explored to show the generality of this reaction for the
direct synthesis of 9,10-substituted phenanthrene. We were
delighted to find that the optimized reaction conditions were so
robust and versatile that the ketone could also be used as a
substrate to synthesize 9,10-substituted phenanthrene 2o in
high yield, 85% (Scheme 4) in 15 h. However, because of the
lesser reactivity of ketone, the reaction was sluggish compared
to aldehyde.
Scheme 5. Plausible Mechanism for the Formation of
Phenanthrene
In general, this method is quite simple and high yielding, and
only a catalytic amount of FeCl3 (5 mol %) is required for this
process. This reaction worked smoothly and efficiently with a
wide range of functional groups containing substrates. These
results indicated that there is no significant electronic effect of
substituents. Moreover, the products obtained in this method
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Note
Step 1. Preparation of 1-Bromo-2-(phenylethynyl)benzene (7).
To a solution of compound 7 (1 g, 3.53 mmol) in THF, Pd(PPh3)4
(0.05 equiv), CuI (0.1 equiv), BuNH2 (1.4 equiv) and phenyl
acetylene (1.2 equiv) were added successively under argon
atmosphere. The mixture was stirred at 70 °C for 11 h. After
completion of reaction (monitored by TLC), the mixture was cooled
and solvent was evaporated under reduced pressure. To this mixture,
water was added (20 mL) and then extracted with dichloromethane
and dried over anhydrous Na2SO4. The crude compound was purified
using silica gel (60−120 mesh) column chromatography (petroleum
ether/EtOAc) to afford compound 8 (760 mg, 84%) as colorless
liquid: 1H NMR (500 MHz, CDCl3) δ 7.09 (t, J = 7.0 Hz, 1H), 7.11−
7.31 (m, 4H), 7.46−7.54 (m, 4H) ppm; 13C NMR (125 MHz, CDCl3)
δ 88.2, 94.1, 122.0, 127.2, 128.5, 128.6, 128.8, 129.4, 129.5, 131.9,
132.6, 132.7, 133.4 ppm.
carbonyl group of 1, which enhances the electrophilicity of
carbonyl carbon. Then subsequent intramolecular nucleophilic
attack by the alkyne moiety onto the polarized carbonyl carbon
generating a vinylic carbocation intermediate 6, which
immediately cyclized by nucleophilic attack of the carbonyl
oxygen center forming an oxetene intermediate 7. Then a
subsequent [2 + 2] cycloreversion of oxetene intermediate
leading to the substituted phenanthrene and regenerating the
iron salts for the next catalytic cycle. It is interesting to note
that while the internal alkyne undergoes smooth coupling with
carbonyl group in the presence of iron, no such coupling takes
place with terminal alkyne. These results can be explained
considering the greater stability of secondary vinylic carboca-
tion generating from internal alkyne. However, because of the
instability of generating primary vinylic carbocation, terminal
alkyne does not participate in this reaction. Moreover, aryl
substituted internal alkynes in general produced higher yield
compared to the alkyl substituted terminal alkyne. This result
further supported the formation of vinylic intermediate 6.
In summary, we have developed an efficient iron-catalyzed
intramolecular alkyne−carbonyl metathesis reaction for the
regioselective synthesis of multisubstituted phenanthrene
skeletons. The advantages of this new method are the ease of
the substrate preparation, operational simplicity, high atom
economy, and use of inexpensive and environmentally friendly
FeCl3 (5 mol %) as catalyst. This coupling reaction is
compatible with a wide range of functional groups such as
methyl, methoxy, fluoride, chloride and ester groups. Moreover,
variation of functional groups was proven possible in all the
rings of phenanthrene motif. In addition, this method also
works for the synthesis of a tetracyclic compound. Considering
these, the present synthetic strategy of phenanthrene may find
application toward the synthesis of many biologically active
molecules and new polycyclic aromatic compounds.
Step 2. Preparation of 2′-(Phenylethynyl)biphenyl-2-carbalde-
hyde (1a). The compound 8 (1 g, 3.9 mmol), 2-formyl phenylboronic
acid (770 mg, 4.3 mmol) and Pd(PPh3)4 (0.02 equiv, 90 mg) were
suspended in toluene (5 mL). Then ethanol (5 mL) and K2CO3 (2.5
M) were added to it. The mixture was stirred thoroughly under argon
atmosphere and heated to 90 °C for 18 h. After completion of
reaction, toluene was evaporated under reduced pressure and crude
product was extracted with ethyl acetate. The crude mixture was
partitioned between ethyl acetate (25 mL) and brine (25 mL), and the
aqueous layer was extracted with ethyl acetate (3 × 25 mL). The
combined organic layers were dried over Na2SO4, and solvent was
removed under reduced pressure to yield the crude product 1a as dark
1
red liquid (770 mg, 70%): H NMR (300 MHz, CDCl3) δ 7.15−7.18
(m, 2H), 7.22−7.25 (m, 2H), 7.40−7.46 (m, 4H), 7.55 (t, J = 7.5 Hz,
2H), 7.62−7.70 (m, 2H), 8.09 (d, J = 7.7 Hz, 2H), 9.93 (s, 1H) ppm;
13C NMR (75 MHz, CDCl3) δ 88.4, 93.1, 123.8, 127.0, 128.4, 128.6,
130.4, 131.4, 132.1, 133.6, 140.4, 144.5, 192.0 ppm; HRMS calcd. for
C21H14NaO [M + Na] 305.0942, found 305.0940.
The compounds 1b−1o were synthesized by similar procedure.
Spectral data of compounds 1b−1o are given below:
5′-Methyl-2′-(phenylethynyl)biphenyl-2-carbaldehyde (1b). Yield
1
70%, orange-red liquid: H NMR (300 MHz, CDCl3) δ 2.44 (s, 3H),
7.18−7.21 (m, 2H), 7.23−7.26 (m,5H), 7.46 (d, J = 7.6 Hz, 1H),
7.54−7.58 (m, 2H), 7.64−7.69 (m, 1H), 8.13 (d, J = 7.7 Hz, 1H), 9.99
(s, 1H) ppm; 13C NMR (75 MHz, CDCl3) δ 21.5, 88.4, 93.1, 120.8,
122.9, 126.8, 128.2, 128.3, 129.1, 131.1, 131.2, 131.3, 131.9, 133.5,
134.3, 138.7, 140.2, 144.5, 191.9 ppm; HRMS calcd. for C22H16NaO
[M + Na] 319.1099, found 319.1105.
EXPERIMENTAL SECTION
General Methods. H NMR spectra were recorded with 300 and
■
1
500 MHz spectrometer in CDCl3. Chemical shifts are expressed in
parts per million (ppm, δ) and are referenced to CHCl3 (δ = 7.26
ppm) as an internal standard. All coupling constants are absolute
values and are expressed in Hz. The description of the signals include
the following: s = singlet, d = doublet, t = triplet, m = multiplet, dd =
doublet of doublets and brs = broad singlet. 13C NMR spectra were
recorded with spectrometer in CDCl3 with complete proton
decoupling. Chemical shifts are expressed in parts per million (ppm,
δ) and are referenced to CDCl3 (δ = 77.0 ppm) as an internal
standard. High-resolution mass spectra (HRMS) were obtained using
a TOF spectrometer using simultaneous electrospray (ESI) method.
The molecular fragments are quoted as the relation between mass and
charge (m/z). IR (infrared spectroscopy) was recorded with an FT-IR
spectrometer. The routine monitoring of reactions was performed with
silica gel coated glass slides and precoated Al plate, which were
analyzed with iodine and UV light, respectively. All reactions involving
moisture-sensitive reactants were executed with oven-dried glassware.
Anhydrous FeCl3 was purchased from Alfa aesar, Germany (98%) and
SRL, India (98%).
5′-Methoxy-2′-(phenylethynyl)biphenyl-2-carbaldehyde (1c).
1
Yield 75%, orange-red liquid: H NMR (300 MHz, CDCl3) δ 3.86
(s, 3H), 6.95−6.99 (m, 2H), 7.15−7.17 (m, 2H), 7.22−7.26 (m. 3H),
7.45 (d, J = 7.5 Hz, 1H), 7.52−7.59 (m, 2H), 7.64−7.69 (m, 1H), 8.11
(d, J = 7.7 Hz, 1H), 9.97 (s, 1H) ppm; 13C NMR (75 MHz, CDCl3) δ
55.5, 88.2, 92.3, 114.0, 115.9, 116.1, 123.1, 126.8, 128.1, 128.2, 128.3,
131.1, 133.4, 133.5, 134.2, 141.9, 144.2, 159.6, 191.8 ppm; HRMS
calcd. for C22H16NaO2 [M + Na] 335.1048, found 335.1053.
5′-Fluoro-2′-(phenylethynyl)biphenyl-2-carbaldehyde (1d). Yield
70%, brown solid: 1H NMR (500 MHz, CDCl3) δ 7.14−7.16 (m, 4H),
7.22−7.25 (m, 3H), 7.42 (d, J = 7.5 Hz, 1H), 7.57 (t, J = 7.5 Hz, 1H),
7.61−7.64 (m, 1H), 7.67−7.70 (m, 1H), 8.09 (d, J = 7.5 Hz, 1H), 9.94
(s, 1H) ppm; 13C NMR (75 MHz, CDCl3) δ 87.1, 93.3, 115.4, 115.6,
117.2, 117.5, 119.9, 120.0, 122.4, 127.1, 128.1, 128.2, 128.4, 128.6,
130.0, 130.9, 131.2, 133.6, 133.7, 133.8, 134.1, 142.6, 142.9, 149.7,
160.4, 163.8, 191.2 ppm; HRMS calcd. for C21H14FO [M + H]
301.1029, found 301.1025.
5′-Chloro-2′-(phenylethynyl)biphenyl-2-carbaldehyde (1e). Yield
80%, yellow solid: 1H NMR (300 MHz, CDCl3) δ 7.12−7.17 (m, 2H),
7.22−7.79 (m, 3H), 7.40 (s, 1H), 7.43 (s, 2H), 7.55−7.60 (m, 2H),
7.69 (t, J = 6.9 Hz, 1H), 8.10 (d, J = 7.7 Hz, 1H), 9.94 (s, 1H) ppm;
13C NMR (75 MHz, CDCl3) δ 87.1, 94.6, 122.3, 127.1, 128.2, 128.4,
128.6, 128.7, 130.1, 131.0, 131.2, 132.9, 133.6, 134.1, 134.3, 141.9,
142.7, 191.2 ppm; HRMS calcd. for C21H14ClO [M + H] 317.0733,
found 317.0738.
Representative Experimental Procedure for the Preparation
of 2′-Alkynyl-biphenyl-2-carbaldehydes (1a).
Ethyl 2′-formyl-6-(phenylethynyl)biphenyl-3-carboxylate (1f).
1
Yield 50%, faint yellow solid: H NMR (300 MHz, CDCl3) δ 1.41
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Note
(t, J = 7.1 Hz, 3H), 4.41 (q, J = 7.1 Hz, 2H), 7.15−7.18 (m, 2H),
7.22− 7.31 (m, 3H), 7.45 (d J = 7.6 Hz, 1H), 7.58 (t, J = 7.5 Hz, 1H),
7.67−7.72 (m, 2H), 8.11 (d, J = 6.9 Hz, 3H), 9.92 (s, 1H) ppm; 13C
NMR (75 MHz, CDCl3) δ 14.3, 61.4, 87.7, 96.7, 122.1, 127.2, 128.1,
128.3, 128.6, 128.9, 129.1, 130.1, 131.0, 131.3, 131.4, 131.9, 133.7,
134.2, 140.5, 143.3, 165.7, 191.3 ppm; HRMS calcd. for C24H18NaO3
[M + H] 377.1154, found 377.1159.
31.9, 79.5, 99.2, 124.5, 126.6, 127.6, 127.9, 128.0, 129.0, 129.7, 129.9,
131.1, 131.9, 133.4, 134.1, 134.4, 140.2, 144.7, 191.8 ppm; HRMS
calcd. for C21H20NaO [M + Na] 311.1412, found 311.1417.
1-[2′-(Phenylethynyl)biphenyl-2-yl] ethanone (1o). Yield 73%,
1
yellow solid: H NMR (500 MHz, CDCl3) δ 2.17 (s, 3H), 7.22−7.28
(m, 5H), 7.32−7.44 (m, 4H), 7.48 (t, J = 7.5 Hz, 1H), 7.55 (q, J = 7.5
Hz, 1H), 7.62−7.66 (m, 1H), 7.76 (d, J = 7.5 Hz, 1H) ppm; 13C NMR
(125 MHz, CDCl3) δ 29.4, 88.6, 93.2, 122.4, 123.1, 127.5, 127.7,
128.1, 128.3, 128.5, 129.2, 129.5, 130.9, 131.0, 131.1, 131.4, 132.2,
132.8, 139.9, 140.3, 143.9, 202.1 ppm; HRMS calcd. for C22H16NaO
[M + H] 319.1099, found 319.1105.
2-[2-(Phenylethynyl)naphthalen-1-yl]benzaldehyde (1g). Yield
1
65%, faint yellow oil: H NMR (500 MHz, CDCl3) δ 7.10 (d, J =
8.0 Hz, 2H), 7.21−7.26 (m, 3H), 7.43 (s, 2H), 7.46 (d, J = 8.0 Hz,
1H), 7.50−7.53 (m, 1H), 7.64 (t, J = 7.5 Hz, 1H), 7.69 (d, J = 8.5 Hz,
1H), 7.76 (t, J = 7.5 Hz, 1H), 7.91 (d, J = 8.5 Hz, 2H), 8.19 (d, J = 7.5
Hz, 1H), 9.66 (s, 1H) ppm; 13C NMR (75 MHz, CDCl3) δ 89.0, 94.9,
121.7, 122.8, 126.3, 126.8, 127.1, 127.3, 128.0, 128.3, 128.4, 128.5,
128.5, 131.4, 132.1, 132.8, 132.9, 133.7, 135.2, 138.4, 142.9, 191.8
ppm; HRMS calcd. for C25H16NaO [M + Na] 355.1099, found
355.1094.
General Experimental Procedure for the Synthesis of
Phenanthrene. Representative Experimental Procedure for the
synthesis of Phenanthrene-9-yl (phenyl)methanone (2a). Com-
pound 1a (140 mg, 0.5 mmol) was taken in a 10 mL round-bottom
flask containing 3 mL of dry 1,2-dichloroethane. Anhydrous FeCl3 (4.0
mg, 0.025 mmol) was added to it, and the reaction mixture was heated
to reflux for 4 h under an Ar atmosphere. After completion of the
reaction (TLC), dichloroethane was distilled out under reduced
pressure and the residue was purified by silica gel (mesh 60−120)
column chromatography (petroleum ether/EtOAc) to afford 2a (121
2′-(p-Tolylethynyl)biphenyl-2-carbaldehyde (1h). Yield 80%,
1
orange oil: H NMR (500 MHz, CDCl3) δ 2.31 (s, 3H), 7.04−7.08
(m, 4H), 7.39−7.45 (m, 4H), 7.54 (t, J = 7.5 Hz, 1H), 7.63−7.68 (m,
2H), 8.09 (d, J = 7.5 Hz, 1H), 9.94 ppm; 13C NMR (125 MHz,
CDCl3) δ 21.6, 87.7, 94.2, 119.8, 124.1, 127.0, 128.3, 129.2, 130.3,
131.3, 131.4, 132.0, 133.5, 134.4, 138.7, 140.3,144.5, 191.9 ppm;
HRMS calcd. for C22H16NaO [M + Na] 319.1099, found 319.1106.
2′-[(4-Chlorophenyl)ethynyl]biphenyl-2-carbaldehyde (1i). Yield
50%, yellow oil: 1H NMR (300 MHz, CDCl3) δ 7.08 (d, J = 10.7 Hz,
2H), 7.21 (d, J = 8.6 Hz, 2H), 7.34 (s, 1H), 7.42−7.45 (m, 2H), 7.52−
7.57 (m, 2H), 7.62−7.70 (m, 2H), 8.08 (d, J = 7.7 Hz, 1H), 9.91 (s,
1H) ppm; 13C NMR (75 MHz, CDCl3) δ 89.1, 92.6, 121.1, 122.9,
123.4, 126.8, 127.3, 128.2, 128.4, 128.6, 129.5, 130.2, 131.0, 131.2,
131.9, 132.4, 132.6, 133.4, 134.5, 140.4, 144.1, 191.7 ppm; HRMS
calcd. for C21H13ClNaO [M + Na] 339.0553, found 335.0559.
2′-[(3-nitrophenyl)ethynyl]biphenyl-2-carbaldehyde (1j). Yield
1
mg, 0.43 mmol, 86%) as a yellow oil: H NMR (500 MHz, CDCl3) δ
7.49 (t, J = 7.5 Hz, 2H), 7.59−7.65 (m, 3H), 7.70−7.78 (m, 2H), 7.88
(s, 1H), 7.91 (d, J = 8.0 Hz, 1H), 7.97 (d, J = 7.0 Hz, 2H), 8.15 (d, J =
8.0 Hz, 1H), 8.77 (dd, J = 18.0 Hz, 8.0 Hz, 2H) ppm; 13C NMR (125
MHz, CDCl3) δ 122.9, 123.1, 126.8, 127.3, 127.3, 128.4, 128.7, 129.3,
129.5, 129.6, 130.2, 130.6, 130.8, 131.5, 133.5, 135.5, 138.4, 198.0;
HRMS calcd. for C21H15O [M + H] 283.1123, found 283.1128.
1-(6-Methylphenanthrene-9-yl)ethanone (2b). Compound 1b
(155 mg, 0.5 mmol) and anhydrous FeCl3 (4.0 mg, 0.025 mmol)
were treated in dry 1,2-dichloroethane as described for the synthesis of
2a for 6 h to afford 2b (113 mg, 0.38 mmol, 75%) as a yellow solid:
1
mp 130 °C; IR (KBr) 3063, 2360, 1665, 1252, 749 cm−1; H NMR
1
(500 MHz, CDCl3) δ 2.63 (s, 3H), 7.42 (d, J = 8.5 Hz, 1H), 7.47 (t, J
= 8.0 Hz, 2H), 7.62 (t, J = 7.5 Hz, 2H), 7.73 (t, J = 7.0 Hz, 1H), 7.79
(s, 1H), 7.87 (d, J = 8.0 Hz, 1H), 7.95 (d, J = 8.0 Hz, 2H), 8.02 (d, J =
8.0 Hz, 1H), 8.56 (s, 1H), 8.73 (d, J = 8.0 Hz, 1H) ppm; 13C NMR
(125 MHz, CDCl3) δ 22.2, 122.8, 126.6, 127.1, 127.4, 128.2, 128.4,
128.6, 129.1, 129.6, 130.4, 130.6, 130.9, 131.2, 133.4, 135.4, 137.2,
138.4, 198.2 ppm; HRMS calcd. for C22H17O [M + H] 297.1279,
found 297.1281.
(6-Methoxyphenanthrene-9-yl)(phenyl)methanone (2c). Com-
pound 1c (156 mg, 0.5 mmol) and anhydrous FeCl3 (4.0 mg, 0.025
mmol) were treated in dry 1,2-dichloroethane as described for the
synthesis of 2a for 6 h to afford 2c (119 mg, 0.38 mmol, 75%) as a
yellow liquid: IR (KBr) 2924, 2322, 1655, 1617, 1229, 1062, 724 cm−1;
1H NMR (300 MHz, CDCl3) δ 4.02 (s, 3H), 7.23 (dd, J = 9.1 Hz, 2.6
Hz, 1H), 7.48 (t, J = 7.5 Hz, 2H), 7.62 (t, J = 7.6 Hz, 2H), 7.69−7.75
(m, 2H), 7.86 (d, J = 7.3 Hz, 1H), 7.96 (d, J = 7.1 Hz, 2H), 8.09 (d, J
= 9.1 Hz, 1H), 8.12 (s, 1H), 8.65 (d, J = 8.3 Hz, 1H) ppm; 13C NMR
(75 MHz, CDCl3) δ 55.4, 104.5, 117.0, 122.7, 123.9, 127.1, 127.2,
127.9, 128.1, 128.5, 129.5, 130.4, 130.5, 130.7, 132.3, 133.3, 135.1,
138.3, 158.7, 198.0 ppm; HRMS calcd. for C22H17O2 [M + H]
313.1229, found 313.1233.
70%, yellow solid: H NMR (300 MHz, CDCl3) δ 7.42−7.52 (m,
6H), 7.60 (t, J = 7.5 Hz, 1H), 7.66−7.74 (m, 2H), 8.0 (s, 1H), 8.11 (d,
J = 7.2 Hz, 2H), 9.92 (s, 1H) ppm; 13C NMR (75 MHz, CDCl3) δ
90.7, 91.2, 122.7, 123.0, 124.5, 126.1, 127.0, 128.4, 128.5, 129.3, 129.3,
130.3, 131.3, 132.1, 133.6, 134.3, 136.8, 140.8, 143.9, 148.1, 191.7
ppm; HRMS calcd. for C21H13NNaO3 [M + Na] 350.0793, found
350.0794.
2′-[(6-Methoxynaphthalen-2-yl)ethynyl]biphenyl-2-carbalde-
1
hyde (1k). Yield 70%, yellow liquid: H NMR (300 MHz, CDCl3) δ
3.90 (s, 3H), 7.06 (s, 1H), 7.10−7.17 (m, 2H), 7.39−7.47 (m, 3H),
7.49 (s, 1H), 7.57 (s, 1H), 7.61 (d, J = 5.9 Hz, 2H), 7.65−7.72 (m,
3H), 8.12 (d, J = 7.7 Hz, 1H), 9.97 (s, 1H) ppm; 13C NMR (75 MHz,
CDCl3) δ 55.3, 87.9, 94.5, 105.8, 119.3, 123.9, 126.7, 126.9, 128.2,
128.3, 128.3, 128.5, 129.4, 130.3, 131.1, 131.3, 131.9, 133.5, 134.2,
134.3, 140.2, 144.4, 158.4, 191.9 ppm; HRMS calcd. for C26H18NaO2
[M + Na] 385.1204, found 385.1209.
2′-(1-Octynyl)biphenyl-2-carbaldehyde (1l). Yield 75%, yellowish-
red oil: 1H NMR (500 MHz, CDCl3) δ 0.83−0.88 (m, 2H), 1.08−1.15
(m, 4H), 1.21−1.35 (m, 4H), 2.15 (t, J = 6.9 Hz, 2H), 7.30−7.40 (m,
4H), 7.47−7.52 (m, 2H), 7.63 (t, J = 7.4 Hz, 1H), 8.03 (d, J = 7.7 Hz,
1H), 9.85 (s, 1H) ppm; 13C NMR (125 MHz, CDCl3) δ 14.2, 19.4,
22.6, 28.2, 28.4, 31.6, 79.5, 95.6, 124.6, 126.8, 127.8, 128.1, 128.2,
130.2, 131.2, 132.1, 133.5, 134.3, 140.3, 144.8, 192.0 ppm; HRMS
calcd. for C21H22NaO [M + Na] 313.1568, found 313.1574.
(6-Fluorophenanthrene-9-yl)(phenyl)methanone (2d). Com-
pound 1d (150 mg, 0.5 mmol) and anhydrous FeCl3 (4.0 mg, 0.025
mmol) were treated in dry 1,2-dichloroethane as described for the
synthesis of 2a for 6 h to afford 2d (111 mg, 0.37 mmol, 73%) as a
2′-(4-Methoxybut-1-ynyl)biphenyl-2-carbaldehyde (1m). Yield
1
1
60%, yellow liquid: H NMR (500 MHz, CDCl3) δ 2.32 (t, J = 6.5
yellow solid: mp 98 °C; IR (KBr) 1651, 1594, 1250, 751 cm−1; H
Hz, 2H), 3.14−3.19 (m, 5H), 7.21−7.29 (m, 4H), 7.38−7.42 (m, 2H),
7.53 (t, J = 7.5 Hz, 1H), 7.94 (d, J = 7.5 Hz, 1H), 9.75 (s, 1H) ppm;
13C NMR (75 MHz, CDCl3) δ 20.5, 58.5, 70.2, 80.3, 91.8, 124.0,
126.6, 126.9, 128.0, 128.0, 128.8, 130.1, 131.1, 131.7,132.1, 133.4,
134.1, 140.2, 144.4, 191.8 ppm; HRMS calcd. for C18H16NaO2 [M +
Na] 287.1048, found 287.1048.
NMR (300 MHz, CDCl3) δ 7.30−7.35 (m, 1H), 7.46−7.52 (m, 3H),
7.65 (q, J = 7.2 Hz, 2H), 7.72−7.78 (m, 1H), 7.82 (s, 1H), 7.89 (d, J =
7.8 Hz, 1H), 7.95 (d, J = 7.6 Hz, 2H), 8.18 (dd, J = 9.1 Hz, 5.9 Hz,
1H), 8.35 (dd, J = 10.9 Hz, 2.5 Hz, 1H), 8.58 (d, J = 8.3 Hz, 1H) ppm;
13C NMR (75 MHz, CDCl3) δ 107.9, 108.2, 116.0, 116.3, 122.9, 16.0,
127.7, 128.4, 128.6, 128.8, 128.9, 129.0, 129.6, 130.3, 130.4,
130.6,132.5, 132.6, 133.4, 134.7, 138.1, 160.1, 163.4, 197.5; HRMS
calcd. for C21H13FNaO [M + Na] 323.0848, found 323.0853.
2′-(cyclohexylethynyl)biphenyl-2-carbaldehyde (1n). Yield 60%,
1
brown-yellow liquid: H NMR (300 MHz, CDCl3) δ 1.15−1.24 (m,
5H), 1.36−1.54 (m, 5H), 2.32−2.34 (m, 1H), 7.26−7.33 (m, 4H),
7.42−7.47 (m, 2H), 7.58 (t, J = 7.5 Hz, 1H), 8.02 (d, J = 7.7 Hz, 1H),
9.84 (s, 1H) ppm; 13C NMR (75 MHz, CDCl3) δ 24.5, 25.8, 29.4,
(6-Chlorophenanthrene-9-yl)(phenyl)methanone (2e). Com-
pound 1e (158 mg, 0.5 mmol) and anhydrous FeCl3 (4.0 mg, 0.025
mmol) were treated in dry 1,2-dichloroethane as described for the
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Note
synthesis of 2a for 6 h to afford 2e (108 mg, 0.34 mmol, 68%) as a
as a yellow oil: IR (KBr) 2924, 2322, 1655, 1617, 1300, 1062, 748
1
1
yellow solid: mp 120 °C; IR (KBr) 1651, 1594, 1254, 744 cm−1; H
cm−1; H NMR (300 MHz, CDCl3) δ 3.98 (s, 3H), 7.14−7.18 (m,
NMR (300 MHz, CDCl3) δ 7.49 (t, J = 7.6 Hz, 2H), 7.55 (s, 1H),
7.61−7.68 (m, 2H), 7.75 (t, J = 7.2 Hz, 1H), 7.86 (s, 1H), 7.89 (s,
1H), 7.94 (d, J = 7.2 Hz, 2H), 8.11 (d, J = 8.8 Hz, 1H), 7.62 (d, J = 8.3
Hz, 1H), 8.71 (s, 1H) ppm; 13C NMR (75 MHz, CDCl3) δ 122.6,
122.7, 127.7, 127.8, 128.1, 128.6, 128.7, 129.6, 129.7, 130.3, 130.3,
130.4, 131.9, 133.4, 133.5, 134.6, 138.0, 197.4 ppm; HRMS calcd. for
C21H14ClO [M + H] 317.0733, found 317.0736.
2H), 7.51−7.62 (m, 2H), 7.65−7.70 (m,3H), 7.75 (d, J = 8.2 Hz, 1H),
7.83 (d, J = 8.6 Hz, 1H), 7.92 (s, 1H), 8.15 (d, J = 8.6 Hz, 2H), 8.30
(s, 1H), 8.77 (t, J = 9.4 Hz, 2H) ppm; 13C NMR (75 MHz, CDCl3) δ
55.4, 105.6, 1058, 119.7, 122.7, 123.0, 126.1, 126.7, 127.1, 127.2, 127.7,
128.2, 128.6, 129.5, 130.2, 130.6, 131.2, 131.3, 132.9, 133.5,135.9,
137.6, 158.0, 160.0, 197.8 ppm; HRMS calcd. for C26H19O2 [M + H]
363.1385, found 363.1379.
1-(Phenanthrene-9-yl)heptan-1-one (2l). Compound 1l (145 mg,
0.5 mmol) and anhydrous FeCl3 (4.0 mg, 0.025 mmol) were treated in
dry 1,2-dichloroethane as described for the synthesis of 2a for 6 h to
afford 2l (93 mg, 0.32 mmol, 64%) as a faint yellow oil: IR (KBr)
3063, 2929, 2252, 1693, 908, 732 cm−1; 1H NMR (300 MHz, CDCl3)
δ 0.89−0.93 (m, 3H), 1.31−1.45 (m, 6H), 1.81−1.86 (m, 2H), 3.13 (t,
J = 7.5 Hz, 2H), 7.64−7.74 (m, 4H), 7.95 (d, J = 6.93 Hz, 1H), 8.08
(s, 1H), 8.50−8.53(m, 1H), 8.66−8.74 (m, 2H) ppm; 13C NMR (75
MHz, CDCl3) δ = 14.0, 22.5, 24.7, 29.0, 31.2, 42.4, 122.6, 122.8, 126.5,
127.0, 127.4, 128.4, 128.6, 128.7, 129.6, 129.8, 130.8, 131.6, 132.7,
135.7, 205.2 ppm; HRMS calcd. for C21H22NaO [M + Na] 313.1568,
found 313.1572.
Ethyl-10-Acetylphenanthrene-3-carboxylate (2f). Compound 1f
(185 mg, 0.5 mmol) and anhydrous FeCl3 (4.0 mg, 0.025 mmol) were
treated in dry 1,2-dichloroethane as described for the synthesis of 2a
for 1.5 h to afford 2f (144 mg, 0.39 mmol, 79%) as a yellowish white
solid: mp 110 °C; IR (KBr) 3064, 2983, 2252, 1710, 1660, 1255, 910,
1
734 cm−1; H NMR (300 MHz, CDCl3) δ 1.48 (t, J = 7.1 Hz, 3H),
4.49 (q, J = 7.1 Hz, 2H), 7.45−7.50 (m, 2H), 7.60−7.68 (m, 2H), 7.79
(t, J = 7.1 Hz, 1H), 7.88−7.95 (m, 4H), 8.18 (s, 1H), 8.83 (d, J = 8.3
Hz, 1H), 9.49 (s, 1H) ppm; 13C NMR (75 MHz, CDCl3) δ 14.5, 61.3,
123.0, 125.3, 126.7, 127.0, 127.7, 128.6, 128.7, 129.0, 129.7, 130.2,
130.4, 131.5, 132.1, 133.6, 134.8, 138.0, 166.6, 197.4 ppm; HRMS
calcd. for C24H19O3 [M + H] 355.1334, found 355.1328.
Benzo[c]phenanthrene-6-yl (phenyl)methanone (2g). Compound
1g (166 mg, 0.5 mmol) and anhydrous FeCl3 (4.0 mg, 0.025 mmol)
were treated in dry 1,2-dichloroethane as described for the synthesis of
2a for 8 h to afford 2g (143 mg, 0.43 mmol, 85%) as a yellow oil: IR
(KBr) 2919, 1655, 1594, 1265, 748 cm−1; 1H NMR (300 MHz,
CDCl3) δ 7.48 (t, J = 7.5 Hz, 2H), 7.60−7.69 (m, 3H), 7.72−7.79 (m,
2H), 7.88 (d, J = 8.9 Hz, 1H), 7.98−8.04 (m, 5H), 8.07 (s, 1H), 9.14
(d, J = Hz, 2H) ppm; 13C NMR (75 MHz, CDCl3) δ 123.7, 126.3,
126.5, 126.5, 127.6, 127.9, 128.2, 128.3, 128.4, 128.6, 128.8, 129.2,
130.5, 131.1, 131.5, 133.3, 133.5, 138.2, 198.1 ppm; HRMS calcd. for
C25H16NaO [M + Na] 355.1099, found 355.1104.
3-Methoxy-1-(phenanthrene-9-yl)propan-1-one (2m). Com-
pound 1m (132 mg, 0.5 mmol) and anhydrous FeCl3 (4.0 mg,
0.025 mmol) were treated in dry 1,2-dichloroethane solvent at 60 °C
following the procedure as described for the synthesis of 2a for 4 h to
afford 2m (79 mg, 0.30 mmol, 60%) as a faint yellow solid: mp 70 °C;
1
IR (KBr) 2886, 2360, 1664, 1114, 747, 723 cm−1; H NMR (300
MHz, CDCl3) δ 3.38 (t, J = 6.3 Hz, 2H), 3.41 (s, 3H), 3.91 (t, J = 6.2
Hz, 2H), 7.59−7.75 (m, 4H), 7.92 (d, J = 7.9 Hz, 1H), 8.13 (s, 1H),
8.58−8.71 (m, 3H) ppm; 13C NMR (75 MHz, CDCl3) δ 42.2, 58.9,
68.2, 122.6, 122.7, 126.6, 127.0, 127.4, 128.2, 128.7, 129.5, 129.7,
129.9, 130.7, 131.7, 135.1, 202.6 ppm; HRMS calcd. for C18H16NaO2
[M + Na] 287.1048, found 287.1051.
Phenanthrene-9-yl (p-tolyl)methanone (2h). Compound 1h (148
mg, 0.5 mmol) and anhydrous FeCl3 (4.0 mg, 0.025 mmol) were
treated in dry 1,2-dichloroethane as described for the synthesis of 2a
for 5 h to afford 2h (86 mg, 0.29 mmol, 57%) as a yellow oil: IR (KBr)
Cyclohexyl (phenanthrene-9-yl)methanone (2n). Compound 1n
(144 mg, 0.5 mmol) and anhydrous FeCl3 (4.0 mg, 0.025 mmol) were
treated in dry nitromethane at 60 °C following the procedure as
described for the synthesis of 2a for 7 h to afford 2n (66 mg, 0.23
mmol, 45%) as a yellow oil: IR (KBr) 3072, 2921, 2850, 1681, 1444,
728 cm−1; 1H NMR (300 MHz, CDCl3) δ 1.26−1.45 (m, 4H), 1.52−
1.75 (m, 2H), 1.83−1.88 (m, 2H), 1.98−2.03 (m, 2H), 3.24−3.33 (m,
1H), 7.60−7.76 (m, 4H), 7.93−7.96 (m, 2H), 8.22 (dd, J = 8.0 Hz,
1.42 Hz, 1H), 8.71 (t, J = 9.4 Hz, 2H) ppm; 13C NMR (75 MHz,
CDCl3) δ 25.8, 26.0, 28.9, 50.0, 122.7, 122.9, 126.4, 126.9, 127.1,
127.3, 128.3, 128.8, 129.5, 130.2, 130.7, 131.4, 136.6, 208.7 ppm;
HRMS calcd. for C21H21O [M + H] 289.1592, found 289.1596.
(10-Methylphenanthren-9-yl)(phenyl)methanone (2o). Com-
pound 1o (156 mg, 0.5 mmol) and anhydrous FeCl3 (8.0 mg, 0.05
mmol) were treated in dry 1,2-dichloroethane solvent as described for
the synthesis of 2a for 15 h to afford 2o (133 mg, 0.43 mmol, 85%) as
a yellow solid: mp 164 °C; IR (KBr) 3047, 2918, 2845, 2358, 1664,
1
3063, 2924, 2251, 1651, 1604, 908, 732 cm−1; H NMR (300 MHz,
CDCl3) δ 2.44 (s, 3H), 7.28 (d, J = 8.0 Hz, 2H), 7.56−7.77 (m, 4H),
7.85−7.90 (m, 4H), 8.11 (d, J = 8.2 Hz, 1H), 8.75 (t, J = 8.6 Hz, 2H)
ppm; 13C NMR (75 MHz, CDCl3) δ 21.7, 122.7, 122.9, 126.6, 127.1,
127.1, 128.1, 128.7, 129.2, 129.4, 129.4, 130.1, 130.6, 131.2, 135.6,
135.7, 144.4, 197.6 ppm; HRMS calcd. for C22H17O [M + H]
297.1279, found 297.1282.
(4-Chlorophenyl)(phenanthrene-9-yl)methanone (2i). Compound
1i (158 mg, 0.5 mmol) and anhydrous FeCl3 (4.0 mg, 0.025 mmol)
were treated in dry 1,2-dichloroethane as described for the synthesis of
2a for 6 h to afford 2i (133 mg, 0.42 mmol, 83%) as a yellow oil: IR
(KBr) 3059, 2922, 1651, 1585, 1084, 725 cm−1; 1H NMR (300 MHz,
CDCl3) δ 7.45 (d, J = 8.6 Hz, 2H), 7.55−7.76 (m, 5H), 7.84 (s, 1H),
7.89 (d, J = 8.5 Hz, 2H), 8.10 (d, J = 8.2 Hz, 1H), 8.75 (t, J = 9.7 Hz,
2H) ppm; 13C NMR (75 MHz, CDCl3) δ 122.7, 123.0, 126.5, 127.2,
127.3, 128.5, 128.9, 129.1, 129.3, 129.6, 130.0, 130.6, 131.3, 131.8,
134.9, 136.5, 139.9, 196.6 ppm; HRMS calcd. for C21H14ClO [M + H]
317.0733, found 317.0733.
(3-Nitrophenyl)(phenanthrene-9-yl)methanone (2j). Compound
1j (164 mg, 0.5 mmol) and anhydrous FeCl3 (4.0 mg, 0.025 mmol)
were treated in 1,2-dichloroethane as described for the synthesis of 2a
for 1.5 h to afford 2j (128 mg, 0.39 mmol, 77%) as a faint yellow solid:
mp 122 °C; IR (KBr) 3076, 2361, 1655, 1537, 1348, 1254, 723 cm−1;
1H NMR (300 MHz, CDCl3) δ 7.64 (t, J = 7.8 Hz, 3H), 7.70−7.80
(m, 2H), 7.85−7.90 (m, 2H), 8.18 (dd, J = 16.7 Hz, 8.2 Hz, 2H), 8.44
(d, J = 6.2 Hz, 1H), 8.71−8.78 (m, 3H) ppm; 13C NMR (75 MHz,
CDCl3) δ 122.8, 123.2, 124.9, 126.3, 127.4, 127.4, 127.5, 127.6, 128.9,
129.0, 129.7, 129.8, 130.4, 130.8, 131.7, 133.7, 135.8, 139.8, 148.4,
195.3 ppm; HRMS calcd. for C21H14NO3 [M + H] 328.0974, found
328.0970.
1
1574, 1591, 1239, 1163, 883 cm−1; H NMR (500 MHz, CDCl3) δ
2.57 (s, 3H), 7.42−7.49 (m, 3H), 7.55−7.63 (m, 3H), 7.69−7.76 (m,
2H), 7.93 (d, J = 7.5 Hz, 2H), 8.15 (d, J = 8.0 Hz, 1H), 8.77 (dd, J =
22.7 Hz, 8.5 Hz, 2H) ppm; 13C NMR (125 MHz, CDCl3) δ 17.1,
122.9, 123.2, 125.0, 126.1, 126.5, 127.2, 127.3, 129.0, 129.1, 129.4
ppm; HRMS calcd. for C22H16NaO [M + Na] 319.1099, found
319.1103.
ASSOCIATED CONTENT
■
S
* Supporting Information
X-ray crystallographic data of 2b (CIF) and copies of NMR
spectra. This material is available free of charge via the Internet
at http://pubs.acs.org.
(6-Methoxynaphthalene-2-yl)(phenanthren-9-yl)methanone
(2k). Compound 1k (181 mg, 0.5 mmol) and anhydrous FeCl3 (4.0
mg, 0.025 mmol) were treated in dry 1,2-dichloroethane as described
for the synthesis of 2a for 8 h to afford 2k (101 mg, 0.28 mmol, 56%)
AUTHOR INFORMATION
■
Corresponding Author
*E-mail: jumasish2004@yahoo.co.in.
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The Journal of Organic Chemistry
Note
M. A.; Martín, V. S. J. Org. Chem. 2005, 70, 57−62. (h) You, L.; Al-
Rashid, Z. F.; Figueroa, R.; Ghosh, S. K.; Li, G.; Lu, T.; Hsung, R. P.
Synlett 2007, 1656.
Notes
The authors declare no competing financial interest.
(15) Recent literature for intramolecular alkyne−carbonyl metha-
thesis: (a) Iron-catalyzed reaction, see: Bera, K.; Sarkar, S.; Biswas, S.;
Maiti, S.; Jana, U. J. Org. Chem. 2011, 76, 3539−3544 and references
cited therein. (b) Iron-catalyzed intramolecular Prins cyclization of
alkynyl-dimethylacetals, see: Zheng, D.; Gong, Ma, W. Z.; Ma, B.;
Zhao, X.; Xie, Z.; Li, Y. Tetrahedron Lett. 2011, 52, 314−317. (c) A
review on Au-catalysis, see: Liu, L.; Xu, B.; Hammond, G. B. Beilstein J.
Org. Chem. 2011, 7, 606−614 and references cited therein. (d) SbF5-
MeOH catalyzed reaction, see: Saito, A.; Kasai, J.; Odaira, Y.; Fukaya,
H.; Hanzawa, Y. J. Org. Chem. 2009, 74, 5644−5647. (e) TfOH-
catalyzed reaction, see: Jin, T.; Yang, F.; Liu, C.; Yamamoto, Y. Chem.
Commun. 2009, 3533−3535. (f) TFA-catalyzed reaction, see:
ACKNOWLEDGMENTS
■
We acknowledge the financial and infrastructural support from
the UGC-CAS program, Department of Chemistry, Jadavpur
University. The DST-PURSE program is also acknowledged.
K.B., S.S. and S.J. are thankful to the CSIR, New Delhi, India,
for their fellowships.
REFERENCES
■
(1) (a) Floyd, A. J.; Dyke, S. F.; Ward, S. E. Chem. Rev. 1976, 76,
509−562. (b) Cragg, G. M.; Newman, D. J. J. Nat. Prod. 2004, 67,
232−244. (c) Li, Z.; Jin, Z.; Huang, R. Synthesis 2001, 2365−2378.
(2) Colwell, W. T.; Brown, V.; Christie, P.; Lange, J.; Reece, C.;
Yamamoto, K.; Henry, D. W. J. Med. Chem. 1972, 15, 771−775.
(3) (a) Banwell, M. G.; Bezos, A.; Burns, C.; Kruszelnicki, I.; Parish,
C. R.; Su, S.; Sydnes, M. O. Bioorg. Med. Chem. Lett. 2006, 16, 181−
185. (b) Wei, L.; Brossi, A; Kendall, R.; Bastow, K. F.; Morris-
Natschke, S. L.; Shi, Q.; Lee, K.-H. Bioorg. Med. Chem. 2006, 14,
6560−6569.
́ ́
Gonzalez-Rodríguez, C.; Escalante, L.; Varela, J. A.; Castedo, L.; Saa,
C. Org. Lett. 2009, 11, 1531. (g) Combination of Au(I) and Ag(I)-
catalyzed reaction, see: Jin, T.; Yamamoto, Y. Org. Lett. 2007, 9, 5259−
5262.
(16) For recent reviews of iron catalysis, see: (a) Bolm, C.; Legros, J.;
Paih, J. L.; Zani, L. Chem. Rev. 2004, 104, 6217. (b) Enthaler, S.; Junge,
K.; Beller, M. Angew. Chem., Int. Ed. 2008, 47, 3317. (c) Sherry, B. D.;
Furstner, A. Acc. Chem. Res. 2008, 41, 1500. (d) Czaplik, W. M.;
̈
(4) Cannon, J. G.; Khonje, P. R.; Long, J. P. J. Med. Chem. 1975, 18,
110−112.
Mayer, M.; Cvengros,
́
J.; Wangelin, A. J. V. ChemSusChem. 2009, 2,
396.
(5) (a) Lewis, F. D.; Burch, E. L. J. Phys. Chem. 1996, 100, 4055−
4063. (b) Lewis, F. D.; Barancyk, S. V.; Burch, E. L. J. Am. Chem. Soc.
1992, 114, 3866−3870. (c) Machado, A. M.; Munaro, M.; Martins, T.
́
D.; Davila, L. Y. A.; Giro, R.; Caldas, M. J.; Atvars, T. D. Z.; Akcelrud,
L. C. Macromolecules 2006, 39, 3398−3407.
(6) (a) Kim, S.; Lee, J.; Lee, T.; Park, H.; Kim, D. Org. Lett. 2003, 5,
2703−2706. (b) Kim, S.; Lee, T.; Lee, E.; Lee, J.; Fan, G.; Lee, S.; Kim,
D. J. Org. Chem. 2004, 69, 3144−3149. (c) Camacho-Davila, A.;
Herndon, J. W. J. Org. Chem. 2006, 71, 6682−6685. (d) Furstner, A.;
Kennedy, J. W. J. Chem.Eur. J. 2006, 12, 7398−7410. (e) Kim, S.;
Lee, Y.; Lee, M.; Lee, J.; Fu, T.; Song, Y.; Cho, Y.; Kim, J. D. J. Org.
Chem. 2007, 72, 4886−4891.
(7) (a) Wassmundt, F. W.; Kiesman, W. F. J. Org. Chem. 1995, 60,
́
196−201. (b) Almeida, J. F.; Castedo, L.; Fernandez, D.; Neo, A. G.;
Romero, V.; Tojo, G. Org. Lett. 2003, 5, 4939−4941. (c) Harrowven,
D. C.; Nunn, M. I. T.; Fenwick, D. R. Tetrahedron Lett. 2002, 43,
3185−3187. (d) Wang, K.; Lu, M.; Yu, A.; Zhu, X.; Wang, Q. J. Org.
̈
Chem. 2009, 74, 935−938 and references cited therein.
(8) Kim, Y. H.; Lee, H.; Kim, Y. J.; Kim, B. T.; Heo, J.-N. J. Org.
Chem. 2008, 73, 495−501 and references cited therein.
(9) (a) Furstner, A.; Mamane, V. J. Org. Chem. 2002, 67, 6264−6267.
̈
(b) Mamane, V.; Hannen, P.; Furstner, A. Chem.Eur. J. 2004, 10,
̈
4556−4575. (c) Mandal, A. B.; Lee, G.-H.; Liu, Y.-H.; Peng, S.-M.;
Leung, M.-K. J. Org. Chem. 2000, 65, 332−336.
(10) (a) Shi, Z.; Ding, S.; Cui, Y.; Jiao, N. Angew. Chem., Int. Ed.
2009, 48, 7895−7898 and reference cited therein. (b) Matsumoto, A.;
Ilies, L.; Nakamura, E. J. Am. Chem. Soc. 2011, 133, 6557−6559.
(c) Wang, C.; Rakshit, S.; Glorius, F. J. Am. Chem. Soc. 2010, 132,
14006−14008.
(11) Ye, F.; Shi, Y.; Zhou, Y.; Xiao, Q.; Zhang, Y.; Wang, J. Org. Lett.
2011, 13, 5020−5023.
(12) Saifuddin, M.; Agarwal, P. K.; Kundu, B. J. Org. Chem. 2011, 76,
10122−10128.
(13) For selected reviews, see: (a) Maryanoff, B. E.; Reitz, A. B.
Chem. Rev. 1989, 89, 863. (b) Cristau, H.-J. Chem. Rev. 1994, 94, 1299.
(c) Li, C. -Y.; Wang, X. -B.; Sun, X. -L.; Zheng, J. -C.; Xu, Z. -H.;
Zhou, Y. -G.; Dai, L. -X. J. Am. Chem. Soc. 2007, 129, 1494−1495.
(14) For intermolecular alkyne−carbonyl metathesis, see: (a) Hay-
ashi, A.; Yamaguchi, M.; Hirama, M. Synlett 1995, 195. (b) Xu, L.-W.;
Li, L.; Xia, C.-Z.; Zhao, P.-Q. Helv. Chim. Acta 2004, 87, 3080.
(c) Curini, M.; Epifano, F.; Maltese, F.; Rosati, O. Synlett 2003, 552.
(d) Kurtz, K. C. M.; Hsung, R. P.; Zhang, Y. Org. Lett. 2006, 8, 231−
234. (e) Saito, A.; Umakoshi, M.; Yagyu, N.; Hanazawa, Y. Org. Lett.
2008, 10, 1783. (f) Viswanathan, G. S.; Lee, C.-J. Tetrahedron Lett.
́
2002, 43, 1613. (g) Miranda, P. O.; Díaz, D. D.; Padron, J. I.; Ramírez,
8786
dx.doi.org/10.1021/jo301371n | J. Org. Chem. 2012, 77, 8780−8786