Decarbonylative halogenation by a vanadium complex

Article abstract of DOI:10.1021/ic302611a

Metal-catalyzed halogenation of the C-H bond and decarbonylation of aldehyde are conventionally done in nature. However, metal-mediated decarbonylative halogenation is unknown. We have developed the first metal-mediated decarbonylative halogenation reaction starting from the divanadium oxoperoxo complex K₃V⁵⁺₂(O ₂^2-)₄(O^2-)₂(μ-OH) (1). A concerted decarbonylative halogenation reaction was proposed based on experimental observations.

Full text of DOI:10.1021/ic302611a

Article
pubs.acs.org/IC
Decarbonylative Halogenation by a Vanadium Complex
Sujoy Rana, Rameezul Haque, Ganji Santosh, and Debabrata Maiti*
Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
*
S Supporting Information
ABSTRACT: Metal-catalyzed halogenation of the C−H bond and
decarbonylation of aldehyde are conventionally done in nature. However,
metal-mediated decarbonylative halogenation is unknown. We have
developed the first metal-mediated decarbonylative halogenation reaction starting from the divanadium oxoperoxo complex
K3V5 2(O2 ) (O ) (μ-OH) (1). A concerted decarbonylative halogenation reaction was proposed based on experimental
+
2−
2−
4
2
observations.
INTRODUCTION
Although decarbonylation of aldehyde and halogenation of
the C−H bond are common in nature, metal-mediated
decarbonylative halogenation is unknown. Therefore, we set
out to develop a synthetic system that would deliver a
decarbonylative halogenation reaction. We postulated that a
divanadium oxoperoxo complex (Scheme 3, M = V) could be a
■
Halogenation occurs during biosynthesis of more than 4000
natural products that display biological activity of pharmaco-
logical interest including anticancer, antibacterial, antiviral,
antifungal, and antiinflammatory activities. Chlorination is the
predominant modification in nature, followed by bromination
and iodination. Vanadium-dependent haloperoxidases (V-
HPOs) are responsible for the majority of halogenation events
Scheme 3. Proposed Decarbonylative Halogenation
Reactions
1
in marine natural products. A common feature of the
haloperoxidases is generation of an η -peroxo intermediate,
2
followed by the formation of vanadium-bound hypohalite,
which is responsible for electrophilic halogenation reactions
2
(Scheme 1).
suitable species based on the following: (1) bioinspired
vanadium oxoperoxo complexes are known for halogenation
reaction (Scheme 4); (2) dimetallic peroxo species are
Scheme 1. Vanadium Oxoperoxo Catalyzed Halogenation in
Nature
2
,6
Scheme 4. Decarbonylative Halogenations by a Vanadium
Catalyst
Like halogenation, aldehyde decarbonylation is another
significant event in nature. The heme−peroxo intermediate of
Cytochrome P450 catalyzes a number of C−C bond cleavage
3
suggested to carry out a decarbonylation reaction in
cyanobacterial aldehyde decarbonylase (AD; Scheme 2).
reactions via aldehyde decarbonylation. Decarbonylation also
4b,c
occurs during biosynthesis of alka(e)ne by cyanobacteria (AD)
Notably, Nam and co-workers reported decarbonylation of
in which a dinuclear nonheme−iron peroxo complex is the
7
3
d,4
aldehyde by a nonheme−iron(III) peroxo complex. Valentine
putative active species (Scheme 2).
On a related note, an
also illustrated that a synthetic peroxoporphyrin complex,
unknown deformylase is also suggested for the DNA
III
2−
−
5
[Fe (TMP)(O )] , can promote direct nucleophilic attack
2
8
demethylase activity.
on an aldehyde.
Scheme 2. Suggested Bimetallic Peroxo Species for
Cyanobacterial AD
RESULTS AND DISCUSSION
■
A bright-yellow divanadium oxoperoxo complex,
5+
2−
2−
K (V ) (O ) (O ) (μ-OH) [K V O H , 1], was synthe-
3
2
2
4
2
3
2
12
3
9
sized from V O /KOH at room temperature in 80% yield. The
2
5
Received: October 18, 2012
©
XXXX American Chemical Society
A
dx.doi.org/10.1021/ic302611a | Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
structure of complex 1 has been reported previously, which we
have further confirmed by X-ray crystallography (Figure 1).
Table 1. Decarbonylative Chlorination by the Vanadium
a
9
,10
Complex 1
Figure 1. Structure of complex 1.
In addition, we have characterized the compound by UV−vis
−
1
−1
(
λ
∼ 320 nm; ε ∼ 1144 M cm ) and IR [ν
= 971
= 886 and 869 cm ]
max
V1O5
−
1
−1
−1
cm , ν
= 942 cm , and ν
spectroscopy. The V NMR spectra clearly suggested that two
V2O11
O−O
9
51
vanadium centers are inequivalent (δ = −731 and −765 ppm),
9
which can also be inferred from the X-ray structure.
7
,8
Unlike in the iron complexes, decarbonylation of aldehydes
was not observed with 1. Interestingly, when we reacted 2-
hydroxy-1-naphthaldehyde with 1 in the presence of KCl (or
KBr), we observed the formation of 1-chloronaphthalen-2-ol
(
Scheme 5 and Table 1, entry 1). Like 2-hydroxy-1-
naphthaldehyde, 2-methoxy-1-naphthaldehye also gave similar
decarbonylative halogenated products (Scheme 5 and Table 1,
entry 2).
1
1
Scheme 5. Reaction of 1 with 2-OR-naphthaldehyde
a
A total of 0.5 mmol of substrate, KCl (12 mmol), citrate−phosphate
buffer (1.5 mL), 6.5 equiv of 30% H O , 1.22 M HCl (1.5 mL),
2
2
acetone (1 mL), room temperature, 24 h. Recovered starting materials
are accounted for in the mass balance. GC yield. H SO /KCl can also
2
4
9
be used with catalyst 1 for decarbonylative chlorination reaction. .
Scheme 6. Concerted Decarbonylative Chlorination
Reactions
Although a methoxy (−OMe) or a hydroxy (−OH) group
ortho to −CHO was successful (Scheme 6), bulkier
substituents [R = allyl (−CH CHCH ), propargyl
2
2
(
−CH CCH), 2-chlorobenzyloxy (−OCH Ar)] failed to
2
2
produce the desired decarbonylative chlorinated products.
Such observations indicate that binding of the −OR group
(
Scheme 6) with the vanadium center is crucial for decarbon-
ylative halogenation reactions.
Three possible pathways for decarbonylative halogenation of
2
-hydroxy-1-naphthaldehyde (or 2-methoxy-1-naphthaldehye)
could be envisioned (Scheme 5): (path 1) oxidation of a
CHO moiety to form −CO H and subsequent decarbox-
−
2
ylation to generate β-naphthol (or 2-methoxynaphthalene),
12
which then can be chlorinated; (path 2) decarbonylation of a
CHO moiety to generate β-naphthol (or 2-methoxynaph-
−
thalene) and chlorination (stepwise); (path 3) a concerted
decarbonylative chlorination.
However, 2-hydroxy-1-naphthaldehyde failed to generate
even a trace of 2-hydroxy-1-naphthoic acid (path 1) or β-
B
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Inorganic Chemistry
Article
,14,15
9
naphthol (path 2) with or without KCl (Scheme 5). We found
that 2-hydroxy-1-naphthoic acid can be decarboxylated (with or
without KCl) and 1-chloronaphthalen-2-ol can be generated in
detected and characterized under the reaction conditions.
This species is likely to be responsible for the concerted
decarbonylative halogenation reactions (Scheme 6). Note that a
9
5+
2−
the presence of KCl (Scheme 5). Also, 2-methoxy-1-naphthoic
structurally related dimeric complex, (NH ) [(V ) (O ) -
4 4 2 2 4
2−
2−
5+
acid can be decarboxylated and/or chlorinated to form 1-
chloro-2-methoxynaphthalene. We further found that β-
naphthol or 2-methoxynaphthalene produced the desired
chlorinated product (with or without KCl and with or without
(O ) (μ-O )], is known to generate such a monomeric V
2
9,15
5+
complex in acidic conditions.
Further, a V species,
V (O )(O )( OH), has previously been suggested in the
literature as the active species formed under acidic
5+
2−
2−
−
2
9
6a,16,17
catalyst 1).
conditions.
−
On a similar note, 2-methoxy-1-naphthaldehyde did not
produce any 2-methoxy-1-naphthoic acid or 2-methoxynaph-
thalene (Scheme 5). On the basis of these experimental
observations, we propose a concerted decarbonylative chlorina-
tion reaction by 1 (Schemes 5 and 6).
Hypochlorite (OCl ) formation under the present reaction
conditions (with catalyst 1; Scheme 7) was proposed based on
detailed reports with a structurally related compound,
5+
2−
2−
2− 15
(NH ) [V 2(O2 ) (O ) (μ-O )].
4
4
4
2
The role of H O was probed for the proposed trans-
Scheme 7. Formation of Vanadium Hypochlorite
2
2
formation. It was concluded that hydrogen peroxide (H O ) is
2
2
required for the (re)generation of vanadium oxoperoxo species
5+
2−
2−
+
[
V (O )(O )] . Without H O , a decarbonylative halo-
2 2 2
genated product was not detected. The Amount of desired
decarbonylative chlorinated product formation increases while
using up to 3.25 mmol of H O . Any further increase of the
2
2
H O amount is detrimental for product formation. Apart from
2
2
acetone, methanol (42% for entry 1 in Table 1) and ethanol
44% for entry 1 in Table 1) were also used as the solvent, and
(
9
acceptable yields of the desired products were obtained. Note
that the formation of acetone peroxide, a well-known
4,18
Similar to cyanobacterial AD,
formic acid was detected
and quantified (yield 52%) from decarbonylative halogenation
of 2-hydroxy-1-naphthaldehyde (63%; Table 1, entry 1) by 1
Scheme 6). At the end of the catalytic reactions (Table 1),
V NMR of the resulting solution was found to contain V
species. The IR data showed two characteristic peaks at 937
) and 887 cm (νO−O), indicating the existence of
a vanadium oxoperoxo moiety. All of these observations are
1
3
explosive, cannot be ruled out completely while using acetone
as the solvent.
9
(
Next we have explored the scope of this decarbonylative
chlorination reaction (Table 1). Various substituents such as
51
5+
−
OH, −OMe, −Br, −NH , and −NO were tolerated. Without
−1
−1
2
2
cm (ν
VO
catalyst 1, desired decarbonylative halogenated products were
not observed. The low yield of the electron-withdrawing nitro
analogue is likely due to an unfavorable electrophilic aromatic
substitution reaction (Table 1, entry 3). Trichloroarene was
generated with amino analogues (entry 6) because of the strong
9
consistent with the proposed mechanism in Scheme 6. Such a
V state is also maintained in V-HPOs throughout the catalytic
5+
1,2
cycle.
o- and p-directing ability of the −NH functional. Control
CONCLUSION
2
■
experiments with either aniline or 2-chloroaniline as the
substrate produced 2,4,6-trichloroaniline (40%). Thus, in the
case of 2-aminobenzaldehyde (entry 6), a combination of a
decarbonylative chlorinated reaction and electrophilic chlorina-
tion led to the formation of 2,4,6-trichloroaniline. Note that
trihalogenation of aniline under acidic conditions has previously
In summary, we have developed the first metal-mediated
decarbonylative halogenation reaction starting from the
divanadium oxoperoxo complex 1. A concerted decarbonylative
halogenation reaction was proposed based on experimental
observations. Characterization of the intermediates and a
detailed understanding of the reaction mechanism is presently
underway in our laboratory.
12
been reported in the literature.
A monomeric vanadium oxoperoxo species, [V (O )-
5
+
2‑
2
−
+
51
−1
(
8
O2 )] ( V NMR, δ −543; IR, 960 cm for ν
and
VO
EXPERIMENTAL SECTION
■
78 cm− for ν ; UV−vis, λ ∼ 330 nm; Figure 2), was
1
O−O
max
Reagent Information. Unless otherwise stated, all of the reactions
were carried out at room temperature in a 20 mL screw-capped
reaction tube. Chemicals and solvents were purchased from Aldrich,
Merck, and Alfa Aesar. A gradient elution using petroleum ether and
ethyl acetate was performed, based on Merck Aluminum TLC sheets
(
silica gel 60F254).
Analytical Information. All isolated compounds were charac-
terized by 1H and C NMR spectroscopy, high-resolution mass
13
spectrometry (HRMS), and gas chromatography−mass spectrometry
(
(
GC−MS). IR spectra were recorded on a Fourier transform infrared
FT-IR) spectrophotometer with samples prepared as KBr pellets.
NMR spectra were recorded either on a Bruker 400 MHz or on a
1
13
51
Varian 400 MHz instrument. Copies of the H, C, and V NMR
1
spectra are attached at the end of this document. All H NMR spectra
were reported in units of parts per million (ppm) and measured
Figure 2. UV−vis spectra of 1 (red, λ = 320 nm), the formation of
relative to the signals for residual chloroform (7.26 ppm) in a
max
5
+
2−
2−
+
13
[
V (O )(O )] species from 1 (green, λ = 330 nm), and the
deuterated solvent, unless otherwise stated. All C NMR spectra were
2
max
catalytically inactive species after completion of the reaction (blue).
reported in ppm relative to CDCl (77.23 ppm), unless otherwise
3
C
dx.doi.org/10.1021/ic302611a | Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
stated, and all were obtained with H decoupling. All 51V NMR spectra
1
40%) was isolated by column chromatography using ethyl acetate in
1
were recorded in D O and reported in ppm relative to NH VO
petroleum ether. H NMR (400 MHz, CDCl ): δ 4.12−4.15 (s, 3H),
2
4
3
3
(
−573.27 ppm). All GC analyses were performed on an Agilent 7890A
GC system with a flame ionization detector using a J&W DB-1 column
10 m × 0.1 mm i.d.). All GC−MS analyses were done by an Agilent
890A GC system connected with a 5975C inert XL EI/CI MSD
with a triple-axis detector).
Preparation of K V O H (1). A solution of V O (1.82 g, 10
7.46−7.51 (d, J = 9.2 Hz, 1H), 8.21−8.27 (d, J = 9.3 Hz, 1H), 8.30−
8.37 (m, 2H), 8.69−8.73 (d, J = 2.4 Hz, 1H), 9.38−9.43 (d, J = 9.7 Hz,
1
3
(
7
1H), 10.83−10.90 (d, J = 1.0 Hz, 1H). C NMR (101 MHz, CDCl ):
3
δ 56.98, 114.85, 122.53, 123.09, 124.75, 126.77, 127.23, 134.86,
139.16, 166.14, 191.47. GC−MS: m/z 231.1 ([M] ).
Preparation of 6-Bromo-2-methoxy-1-naphthaldehyde.
+
(
9
9,21
3
2
12
3
2
5
mmol) in 20 mL of distilled water was taken in a 100 mL round-
bottomed flask and heated to 50−60 °C. Then KOH (2.3 g, 41 mmol)
was added to the reaction mixture, and 1 mL of H O (30%) was
Methylation of 6-bromo-2-naphthol was carried out by following the
methylation step described in the synthesis of 2-methoxy-1-naphthoic
acid. 6-Bromo-2-methoxynaphthalene (0.711 g, 3 mmol) was added in
10 mL of dry toluene along with N-methylformanilide (2.2 mL, 18
mmol) and phosphorus oxychloride (2.8 mL, 30 mmol) at room
temperature. Then, the reaction mixture was refluxed for 12 h at 100
2
2
added to ensure dissolution. The reaction mixture was stirred for 1 h at
°C, and 6 mL of 30% H O was added dropwise. Then it was
0
2
2
warmed to room temperature and stirred for 6 h. The resulting
mixture was filtered through sintered glass under reduced pressure,
washed with cold water twice, and dried under vacuum. From the
aqueous filtrate part, some amount of the complex was recovered by
recrystallization. The yield of the desired product was 80% (3.28 g). 1
was crystallized from a saturated solution of water.
°
C. A solution of potassium acetate (4.57 g) in 15 mL of distilled
water was added to neutralize the resulting reaction mixture.
Subsequently, it was dried under reduced pressure in a rotary
evaporator, 30 mL of water was added, and it was extracted with ethyl
acetate (2 × 50 mL). The organic extract was combined, dried over
Na SO , and concentrated under reduced pressure in a rotary
General Reaction Procedure (A) for the Reaction Setup.
Vanadium catalyst 1 (38 mg, 18 mol %) was taken in a 20 mL reaction
tube along with 1.5 mL of a 1.22 M HCl solution and 1.5 mL of a
citrate−phosphate buffer solution. Then KCl (12 mmol, 0.895 g) and
aldehyde (or alcohol) (0.5 mmol) were added, followed by 1 mL of
acetone. Subsequently, 30% H O (330 μL, 3.25 mmol) was added to
2
4
evaporator. The desired compound, 6-bromo-2-methoxy-1-naphthal-
dehyde (0.238 g, 30%), was isolated by column chromatography using
1
5
% ethyl acetate in petroleum ether (silica gel, 60−120 mesh). H
NMR (400 MHz, CDCl ): δ 3.96−3.98 (s, 3H), 7.14−7.24 (d, J = 9.2
3
2
2
Hz, 1H), 7.55−7.62 (dd, J = 9.3 and 2.2 Hz, 1H), 7.74−7.86 (m, 2H),
the resulting reaction mixture. The reaction mixture was stirred at
room temperature. After 24 h, CH Cl (50 mL) was added to the
9
2
.05−9.15 (d, J = 9.2 Hz, 1H), 10.75−10.80 (s, 1H). GC−MS: m/z
+
2
2
64.1 ([M] ).
reaction mixture and an organic component was extracted (2 × 50 mL
9
−1
Characterization of 1. FT-IR bands (KBr pellet, cm ): ν
V1O5
of CH Cl ). The organic extract was combined, dried over Na SO ,
−1
−1
2
2
2
4
=
8
971 cm and ν
= 942 cm for VO bonds; ν
= 886 and
V2O11
O−O
and concentrated under reduced pressure in a rotary evaporator. The
crude product thus obtained was further purified by column
chromatography.
−1
−4
69 cm for peroxo O−O bonds. A 1.18 × 10 M solution of 1 was
prepared, and the UV−vis spectrum was taken, which showed an
absorption maximum at 320 nm with an absorption coefficient of ε ∼
9,19,20
Preparation of 2-Methoxy-1-naphthoic acid.
A solution
−1
−1
1
144 M cm . The UV−vis feature is characteristic of oxoperoxo
51
of 2-hydroxy-1-naphthoic acid (0.376 g, 2 mmol) in 10 mL of dry
acetone was taken in a 100 mL two-neck round-bottomed flask.
Potassium carbonate (0.828 g, 6 mmol) was added to the flask. The
reaction mixture was heated at 60 °C, and Me SO (0.378 mL, 4
species in the complex. After preparation of complex 1, V NMR
51
studies were done. V NMR (300 MHz, D O): δ −731, −765. Our
2
22,23
findings matched well with the literature report.
2
4
+
9
Characterization of VO(O ) in Solution. Under our standard
2
mmol) was added dropwise by syringe. The resulting reaction mixture
was refluxed overnight. It was cooled to room temperature, filtered
through a funnel plugged with cotton/Celite, and washed with
acetone/ethyl acetate. The organic filtrate was combined, dried over
reaction conditions, after the addition of H O , the resulting solution
2
2
was tested by 51V NMR, UV−vis, and FT-IR spectroscopy. The
51
V
NMR study showed a single peak at −543.7 ppm, while the UV−vis
14
spectrum showed an absorption maximum at 330 nm. FT-IR studies
Na SO , and concentrated. Methyl 2-methoxy-1-naphthoate (0.410 g,
2
4
−1
−1
14
showed two characteristic peaks at 960 cm (ν
) and 878 cm
VO
9
5% yield) was isolated by column chromatography (5% ethyl acetate
in petroleum ether). The brown oily ester was refluxed for 12 h with
0% NaOH (5 mL) to generate the naphthoic acid derivative. The
+
(
νO−O), indicating the presence of VO(O ) formation in solution.
2
9
Characterization of the Final Complex. After decarbonylative
4
halogenation reaction, the aqueous part was dried properly and the IR
spectrum was taken. The IR data showed two characteristic peaks at
reaction mixture was neutralized with 10 N HCl at room temperature,
and the organic part was extracted with ethyl acetate (3 × 50 mL). The
organic extract was combined, dried over Na SO , and concentrated
−
1
−1
9
37 cm (ν
) and 887 cm (νO−O), indicating the presence of
VO
2
4
22
oxoperoxo in the final vanadium complex. After reaction, the
under reduced pressure in a rotary evaporator. The desired compound,
-methoxy-1-naphthoic acid (0.307 g, 80%), was isolated by column
aqueous part was dried under reduced pressure in a rotary evaporator
2
1
and 51V NMR was recorded in D O and reported in ppm relative to
2
chromatography (40% ethyl acetate in petroleum ether). H NMR
51
NH VO (−573.8 ppm). V NMR showed peaks at −520.1, −502.1,
4
3
(
400 MHz, CDCl ): δ 4.02−4.11 (s, 3H), 7.24−7.28 (d, 1H), 7.29−
3
5+
and −423.6 ppm, which indicate the presence of a V oxidation state
at the end of the catalytic cycle.
7
7
8
1
.35 (d, J = 9.1 Hz, 1H), 7.38−7.46 (m, 1H), 7.55−7.61 (m, 1H),
2
2
.79−7.84 (m, 1H), 7.94−8.00 (d, J = 9.1 Hz, 1H), 8.34−8.42 (d, J =
.6 Hz, 1H). 13C NMR (101 MHz, CDCl ): δ 57.35, 113.00, 115.11,
Formic Acid Test. Citric acid (0.5 g, 2.6 mmol) and acetamide (10
g, 169.5 mmol) were dissolved in 100 mL of isopropyl alcohol (R1).
Potassium acetate (30 g) was dissolved in 100 mL of distilled water.
The reaction of 1 with 2-hydroxy-1-naphthaldehyde was carried out
following general procedure A, using 1.5 mL of 0.75 M acid solutions
without adding citrate−phosphate buffer. From the reaction mixture,
0.5 mL of the aqueous part was taken and was neutralized by a KOH
solution; subsequently, 1 mL of R1 and 1 drop of a potassium acetate
solution were added. Subsequently, acetic anhydride (3.5 mL) was
added. The solution was kept at room temperature until a red color
appeared. Then the red solution was diluted with isopropyl alcohol up
to 25 mL in a volumetric flask. The UV−vis spectrum was recorded
with this solution and compared with the red solution obtained from a
standard formate solution’s color test. The molar extinction coefficient
3
24.72, 124.84, 128.42, 128.47, 129.11, 131.76, 133.61, 155.91. GC−
+
MS: m/z 202.1 ([M] ).
Preparation of a Nitro Derivative of 2-Methoxy-1-naph-
9
thaldehyde. A solution of 2-methoxy-1-naphthaldehyde (1 g, 5.37
mmol) was taken in a 100 mL round-bottomed flask, and it was kept at
−
5 °C in an ice bath. Then concentrated HNO (10 mL, d = 1.47) was
added portionwise so that the temperature did not rise above−5 °C
addition was continued for 35 min portionwise). The mixture was
3
(
stirred for another 1 h at room temperature and poured into ice-cold
water. The yellow precipitate was filtered off and subsequently washed
with ethyl acetate. The organic filtrate was collected. The aqueous part
was also extracted with ethyl acetate (2 × 50 mL) to recover the
organic component. Organic extracts were combined, dried over
Na SO , and concentrated under reduced pressure in a rotary
−
1
−1
is 212 M cm . The yield of formic acid was calculated based on
2
4
9
evaporator. Finally, 2-methoxy-6-nitro-1-naphthaldehyde (0.496 g,
UV−vis spectra (52%).
D
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Inorganic Chemistry
Article
1
-Chloro-2-hydroxynaphthalene (Table 1, entry 1). General
Notes
procedure A was followed with 1% ethyl acetate in petroleum ether as
the eluent for column chromatography (silica gel, 100−200 mesh),
and as a white solid (56 mg, 63%) was isolated. The starting material
was recovered (16%). In a separate experiment, a 40% yield of 1-
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
chloro-2-hydroxynaphthalene was obtained with 6 mol % catalyst 1.
This activity was supported by DST-India. Financial support
was received from CSIR-India (fellowship to S.R.), and Indian
Institute of Technology Bombay is gratefully acknowledged by
G.S. D.M. thanks Dr. Rahul Banerjee (NCL-Pune) for helpful
discussions.
1
H NMR (400 MHz, CDCl ): δ 5.94−6.02 (m, 1H), 7.26−7.32 (d, J =
3
8
=
1
1
(
.9 Hz, 1H), 7.38−7.45 (m, 1H), 7.56−7.62 (m, 1H), 7.70−7.74 (d, J
8.8 Hz, 1H), 7.77−7.85 (dd, J = 8.2 and 1.1 Hz, 1H), 8.06−8.10 (m,
H). 13C NMR (101 MHz, CDCl ): δ 113.46, 117.36, 122.90, 124.27,
3
27.70, 128.34, 128.56, 129.58, 131.18, 149.47. GC−MS: m/z 178.1
+
[M] ).
1
-Chloro-2-methoxynaphthalene (Table 1, entry 2). General
REFERENCES
■
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(
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7
1
.34−7.40 (m, 1H), 7.51−7.56 (m, 1H), 7.69−7.76 (m, 2H), 8.17−
.22 (m, 1H). 13C NMR (101 MHz, CDCl ): δ 57.01, 76.88, 77.20,
(2) (a) Schneider, C. J.; Zampella, G.; Greco, C.; Pecoraro, V. L.; De
3
Gioia, L. Eur. J. Inorg. Chem. 2007, 515−523. (b) Schneider, C. J.;
Penner-Hahn, J. E.; Pecoraro, V. L. J. Am. Chem. Soc. 2008, 130,
712−2713. (c) Podgorsek, A.; Zupan, M.; Iskra, J. Angew. Chem., Int.
7.51, 113.71, 116.87, 123.52, 124.40, 127.57, 128.08, 128.12, 129.58,
+
31.95, 152.62. GC−MS: m/z 192.1 ([M] ).
2
1-Chloro-2-methoxy-6-nitronaphthalene (Table 1, entry 3).
Ed. 2009, 48, 8424−8450. (d) Kravitz, J. Y.; Pecoraro, V. L. Pure Appl.
Chem. 2005, 77, 1595−1605. (e) Colpas, G. J.; Hamstra, B. J.; Kampf,
J. W.; Pecoraro, V. L. J. Am. Chem. Soc. 1996, 118, 3469−3478.
(f) Colpas, G. J.; Hamstra, B. J.; Kampf, J. W.; Pecoraro, V. L. J. Am.
Chem. Soc. 1994, 116, 3627−3628.
General procedure A was followed with 1% ethyl acetate in petroleum
ether as the eluent for column chromatography (silica gel, 100−200
mesh), and a yellow powder (6 mg, 5%) was isolated. The starting
1
material was recovered (80%). H NMR (400 MHz, CDCl ): δ 3.97−
3
4
1
(
2
.23 (s, 3H), 7.42−7.49 (d, J = 9.1 Hz, 1H), 7.97−8.03 (d, J = 9.1 Hz,
(
3) (a) Henry, K. M.; Townsend, C. A. J. Am. Chem. Soc. 2005, 127,
H), 8.28−8.36 (m, 2H), 8.76−8.79 (m, 1H). GC−MS: m/z 237.1
+
3724−3733. (b) Roberts, E. S.; Vaz, A. D. N.; Coon, M. J. Proc. Natl.
Acad. Sci. U.S.A. 1991, 88, 8963−8966. (c) Sen, K.; Hackett, J. C. J.
Am. Chem. Soc. 2010, 132, 10293−10305. (d) Patra, T.; Manna, S.;
Maiti, D. Angew. Chem., Int. Ed. 2011, 50, 12140−12142.
[M] ). HRMS (ESI). Calcd for C H NO Cl: 238.0262. Found:
11
8
3
38.0271.
2-Chloroethene-1,1-diyl)dibenzene (Table 1, entry 4).
(
General procedure A was followed with 1% ethyl acetate in petroleum
ether as the eluent for column chromatography, and a yellow powder
(
4) (a) Schirmer, A.; Rude, M. A.; Li, X. Z.; Popova, E.; del Cardayre,
S. B. Science 2010, 329, 559−562. (b) Li, N.; Norgaard, H.; Warui, D.
M.; Booker, S. J.; Krebs, C.; Bollinger, J. M. J. Am. Chem. Soc. 2011,
133, 6158−6161. (c) Krebs, C.; Bollinger, J. M.; Booker, S. J. Curr.
Opin. Chem. Biol. 2011, 15, 291−303.
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12143−12145. (b) Pfaffeneder, T.; Hackner, B.; Truss, M.; Munzel,
M.; Muller, M.; Deiml, C. A.; Hagemeier, C.; Carell, T. Angew. Chem.,
Int. Ed. 2011, 50, 7008−7012. (c) Wu, S. C.; Zhang, Y. Nat. Rev. Mol.
Cell Biol. 2010, 11, 607−620.
(6) (a) Conte, V.; Coletti, A.; Floris, B.; Licini, G.; Zonta, C. Coord.
Chem. Rev. 2011, 255, 2165−2177. (b) Wischang, D.; Brucher, O.;
Hartung, J. Coord. Chem. Rev. 2011, 255, 2204−2217.
(7) (a) Park, M. J.; Lee, J.; Suh, Y.; Kim, J.; Nam, W. J. Am. Chem.
Soc. 2006, 128, 2630−2634. (b) Annaraj, J.; Suh, Y.; Seo, M. S.; Kim,
S. O.; Nam, W. Chem. Commun. 2005, 4529−4531.
(8) Wertz, D. L.; Sisemore, M. F.; Selke, M.; Driscoll, J.; Valentine, J.
S. J. Am. Chem. Soc. 1998, 120, 5331−5332.
(
14 mg, 12%) was isolated. Benzophenone (10%) was obtained as a
1
byproduct, and the starting material was recovered (60%). H NMR
(
400 MHz, CDCl ): δ 6.54−6.64 (d, J = 4.7 Hz, 1H), 7.04−7.45 (m,
3
1
1
1
0H). 13C NMR (101 MHz, CDCl ): δ 116.03, 127.87, 127.91,
3
28.12, 128.22, 128.27, 128.36, 128.41, 128.58, 130.02, 137.75, 140.30,
+
44.05. GC−MS: m/z 214.1 ([M] ). HRMS (ESI). Calcd for
C H Cl O : 215.063. Found: 215.0635.
1
2
10
2
2
6
-Bromo-1-chloro-2-methoxynaphthalene (Table 1, entry
5
). General procedure A was followed with 5% ethyl acetate in
petroleum ether as the eluent for column chromatography, and a
brownish powder (30 mg, 22%) was isolated. The starting material was
1
recovered (65%). H NMR (400 MHz, chloroform-d): δ 3.94−4.08
(
2
q, J = 4.0, 3.9, and 3.9 Hz, 3H), 7.21−7.32 (m, 1H), 7.54−7.67 (m,
13
H), 7.84−7.96 (m, 1H), 7.98−8.10 (m, 1H). C NMR (101 MHz,
CDCl ): δ 57.09, 114.69, 117.11, 118.32, 125.53, 127.19, 130.02,
1
3
+
30.51, 130.60, 130.88, 152.92. GC−MS: m/z 272.1 ([M] ).
,4,6-Trichloroaniline (Table 1, entry 6). General procedure A
2
was followed for 24 h. After workup, the GC yield was determined
using n-decane as the internal standard (25%). The unreacted starting
material (43%) was determined by GC analysis. Product formation
(9) See the Supporting Information for a detailed description.
(10) (a) Grzywa, M.; Rafalska-Lasocha, A.; Lasocha, W. Powder Diffr.
2003, 18, 248−251. (b) Zhang, H. Y.; Huang, Z. X.; Guo, H. X. Chin.
J. Struct. Chem. 2004, 23, 1252−1255.
+
was confirmed by GC−MS [m/z 195 ([M] )].
(11) (a) Wang, Z.; Zhu, L.; Yin, F.; Su, Z.; Li, Z.; Li, C. J. Am. Chem.
ASSOCIATED CONTENT
Supporting Information
Additional data, together with NMR characterization of the
compounds. This material is available free of charge via the
Internet at http://pubs.acs.org.
Soc. 2012, 134, 4258−4263. (b) Johnson, R. G.; Ingham, R. K. Chem.
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Samant, S. D. Ultrason. Sonochem. 2002, 9, 31−35. (d) Perumal, P. T.;
Bhatt, M. V. Tetrahedron Lett. 1979, 3099−3100.
■
*
S
(
12) (a) Vyas, P. V.; Bhatt, A. K.; Ramachandraiah, G.; Bedekar, A. V.
Tetrahedron Lett. 2003, 44, 4085−4088. (b) Moon, B. S.; Choi, H. Y.;
Koh, H. Y.; Chi, D. Y. Bull. Korean Chem. Soc. 2011, 32, 472−476.
(c) Muathen, H. A. Helv. Chim. Acta 2003, 86, 164.
AUTHOR INFORMATION
Corresponding Author
E-mail: dmaiti@chem.iitb.ac.in.
■
*
(
13) (a) Acree, F.; Haller, H. L. J. Am. Chem. Soc. 1943, 65, 1652−
1
652. (b) Schulte-Ladbeck, R.; Kolla, P.; Karst, U. Anal. Chem. 2003,
7
(
5, 731−735. (c) Laird, T. Org. Process Res. Dev. 2004, 8, 815−815.
Author Contributions
All authors have given approval to the final version of the
manuscript.
14) (a) Waidmann, C. R.; DiPasquale, A. G.; Mayer, J. M. Inorg.
Chem. 2010, 49, 2383−2391. (b) Sivak, M. Chem. Pap. 1987, 41, 311−
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E
dx.doi.org/10.1021/ic302611a | Inorg. Chem. XXXX, XXX, XXX−XXX

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−
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(
(
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dx.doi.org/10.1021/ic302611a | Inorg. Chem. XXXX, XXX, XXX−XXX