Synthetic Transformations Using Molecular Oxygen-Doped Carbon Materials

Article abstract of DOI:10.1021/acs.joc.7b00405

Carbon materials like activated carbon (AC) undergo chemisorption with O₂ to give species with electron deficiency in the carbon skeleton and negative charge at the oxygen end that upon reaction with PPh₃ and benzoic acid afford Ph

Full text of DOI:10.1021/acs.joc.7b00405

Note
pubs.acs.org/joc
Synthetic Transformations Using Molecular Oxygen-Doped Carbon
Materials
Mariappan Periasamy,* Masilamani Shanmugaraja, Polimera Obula Reddy, Modala Ramusagar,
and Gunda Ananda Rao
School of Chemistry, University of Hyderabad, Central University P.O., Hyderabad 500046, India
S
* Supporting Information
ABSTRACT: Carbon materials like activated carbon (AC) undergo
chemisorption with O2 to give species with electron deficiency in the
carbon skeleton and negative charge at the oxygen end that upon reaction
with PPh3 and benzoic acid afford Ph3PO. Whereas amine donors react
with O2-chemisorbed AC and nucleophiles to give dehydrogenatively
coupled products in 67−89% yields via the corresponding radical cation
and iminium ion intermediates, the reactions using β-naphthoxide
derivatives give the corresponding oxidatively coupled bi-2-naphthol
products in 68−95% yields.
molecular oxygen to a greater extent than graphite does, which
was reported to undergo only physisorption.
arbon materials like activated carbon (AC) and carbon
Cblack (CB) were reported to undergo chemisorption with
molecular oxygen, and graphite (Gr) undergoes physisorption.1
The characteristics of carbon materials and chemistry of their
surface depend on the heteroatom presence that is in turn
dependent on the nature of the materials and methods used for
their preparation.2 The surface chemistry of the carbon
materials (CM) also depends on the nature and presence of
graphene edge sites. Also, it was suggested that the heteroatom
(like oxygen) free graphene edge sites in carbon materials are
not hydrogen-terminated or free radicals; instead, the edge sites
are aryne-like armchair and carbene-like zigzag sites, but
available evidence points to predominantly carbene-like zigzag
sites 1 (Scheme 1).2
Evidence that chemisorption of molecular oxygen by
activated carbon fiber materials leads to species with electron
deficiency in the material and negative charge at the oxygen end
has been published.1 Accordingly, the transfer of an electron
from the triplet radical carbon site in 2 to the terminal oxygen
resulting in intermediate 3 containing delocalized positive
charge with negative charge on the terminal oxygen may be
visualized as shown in Scheme 1.
It is our goal to design experiments for practical utilization of
oxygen-adsorbed species like 3 in synthetic transformations.
Herein, we wish to report details of investigations of molecular
oxygen-adsorbed carbon materials for use in the development
of new synthetic methods involving reaction with electron rich
compounds. Initially, we performed several experiments to
assess the extent of adsorption of molecular oxygen on carbon
materials. The results are summarized in Table 1. The results
indicate that activated carbon and carbon black samples adsorb
The carbon skeleton of oxygen-adsorbed intermediate 3 is
expected to behave like an electron acceptor, and the negatively
charged oxygen is expected to undergo reaction with proton
donors. Accordingly, such species are expected to react with
proton-containing compounds like benzoic acid to give the
corresponding hydroperoxide intermediate 4 (Scheme 2).
To examine this possibility, we have performed the reaction
of the activated carbon (5 g) with PPh3 (10 mmol) and benzoic
acid (10 mmol). In this experiment, the triphenylphosphine
oxide (Ph3PO) was isolated in 54% yield (Table 2). When
the reaction was performed with water instead of benzoic acid,
the Ph3PO was obtained in only 7% yield. We have observed
that, in the case of carbon black (5 g) without using any proton
source, Ph3PO was formed in 17% yield, whereas using
graphite (5 g), no formation of the Ph3PO product was
observed (Table 2).
We have also observed that the carbon material isolated after
the reaction with PPh3 can be reused after vacuum treatment at
200 °C and re-adsorption of molecular oxygen.3 Reaction using
such reoxidized3 activated carbon with Ph3P in THF gave the
Ph3PO product in 52% yield (Table 2, entry 5).
We have observed that the reaction of benzylamine with
molecular oxygen-adsorbed carbon materials 3 in THF solvent
gives benzaldehyde in 30% yield. In the case of dibenzylamine,
the benzaldehyde was obtained in 25% yield after workup.
However, the NMR spectra obtained for the crude product
mixture before workup and chromatography revealed the
Received: February 20, 2017
© XXXX American Chemical Society
A
DOI: 10.1021/acs.joc.7b00405
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The Journal of Organic Chemistry
Note
Scheme 1. Oxygen Oxidation Reaction at Zigzag Sites of the Carbon Materials
Table 1. Adsorption of Molecular Oxygen on Carbon
Materials
Table 2. Reaction of Molecular Oxygen-Doped Carbon
a
a
Material 3 with Benzoic Acid and PPh3
entry
1
CM (g)
oxygen-adsorbed CM (g)
adsorbed O2 (mmol)
AC (1)
CB (1)
Gr (1)
1.034
1.053
1.000
2.071
2.078
3.092
3.119
4.120
4.152
5.175
5.190
10.203
10.236
15.312
1.06
1.65
−
CM
(g)
benzoic acid
(mmol)
Ph3P
(mmol)
THF
(mL)
Ph3PO yield
b
2
3
4
5
6
7
AC (2)
CB (2)
AC (3)
CB (3)
AC (4)
CB (4)
AC (5)
CB (5)
AC (10)
CB (10)
AC (15)
2.22
2.43
2.88
3.72
3.75
4.75
5.46
5.93
6.34
7.37
9.75
entry
(%)
1
2
3
4
AC (5)
CB (5)
Gr (5)
CB (5)
AC (5)
10
10
0
10
10
10
10
10
20
150
20
54
47
trace
17
0
150
20
c
5
10
52
a
The reactions were performed by using benzoic acid (10 mmol) and
b
c
PPh3 (10 mmol) at 25 °C. Yield. The reaction was performed with
reoxidized activated carbon.
Scheme 3. Dehydrogenative Cross Coupling Reaction in the
Presence of Oxygen-Adsorbed Activated Carbon
a
Carbon materials (CM; AC, activated carbon; CB, carbon black; Gr,
graphite) were heated at 200 °C under high vacuum for 2 h and cooled
to 25 °C under N2. The dry oxygen was passed through the carbon
materials for 1 h at 25 °C.
presence of the imine and benzaldehyde products (S13,
Supporting Information). Presumably, the reaction may give
an amine radical cation followed by formation of imine, which
after reaction with water yields benzaldehyde. The EPR
spectrum recorded after addition of amines to oxygen-adsorbed
activated carbon indicated the presence of paramagnetic species
(S4, 1.5, Supporting Information).
We have also performed a series of experiments using N-
phenyl tetrahydroisoquinoline 6 and activated carbon (1 g) in
organic transformations as outlined in Scheme 3. For example,
when the reaction was performed using N-phenyl tetrahy-
droisoquinoline 6 and 2 equiv of nitromethane in a DMSO
solvent, the dehydrogenative cross coupling product 7 was
obtained in 89% yield. The product 7 was not formed in the
absence of activated carbon. Use of other nucleophilic reagents
like pyrrole and TMSCN gave the corresponding coupling
products 8 and 9 in 75 and 67% yields, respectively. The
oxidized amide derivative 10 was obtained in 72% yield without
using a nucleophile.
upon addition of the amine 6 was confirmed by EPR
spectroscopy (S4, 1.6, Supporting Information).
The reaction of recovered and reoxidized activated carbon3
with N-phenyl tetrahydroisoquinoline 6 and nitromethane gave
the coupled product 7 in 86% yield. To examine the effect of
the radical scavenger like TEMPO on the products, we
performed the reaction of N-phenyl tetrahydroisoquinoline 6
and nitromethane with oxygen-doped carbon materials in the
presence of TEMPO. In this case, the coupled product 7 was
isolated in 93% yield. However, it is to be noted that the
TEMPO+ intermediate was reported to react with the amine 6
to give product 7.4 Accordingly, the results indicate the
formation of the TEMPO+ intermediate in the reaction of
oxygen-adsorbed activated carbon 3 with the radical scavenger
TEMPO (S4, 1.7, Supporting Information).
A tentative mechanism involving the amine radical cation and
iminium ions may be considered to rationalize these trans-
formations (Scheme 4). The formation of paramagnetic species
Scheme 2. Reaction of Oxygen-Doped Carbon Material with PPh3
B
DOI: 10.1021/acs.joc.7b00405
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The Journal of Organic Chemistry
Note
activated carbon was used, the bi-2-naphthol product was
obtained in 95% yield (Table 3, entry 4).
Scheme 4. Tentative Mechanism for Cross Dehydrogenative
Coupling Reaction
We have also observed that the 2-naphthol 17a undergoes
oxidative coupling reaction in the presence of carbon black (2
g) to give bi-2-naphthol 18a in 70% yield under the same
conditions, whereas no bi-2-naphthol 18a product formed
when the reaction was performed using graphite (2 g), again
indicating that molecular oxygen is mainly physisorbed in the
case of graphite. In the absence of carbon additives, the bi-2-
naphthol product 18a was not formed. The substituted 2-
naphthol derivatives 17b and 17c gave the corresponding bi-2-
naphthol derivatives 18b and 18c in 83 and 68% yields,
respectively (Table 3, entries 5 and 6) . We have also observed
that the bi-2-naphthol product 18a was obtained in 93% yield
when the recovered and reoxidized3 activated carbon was
reused in this transformation (Table 3, entry 9).
The oxidative coupling reactions of 2-naphthol 17a using
molecular oxygen-adsorbed carbon materials can be explained
by considering the mechanism outlined in Scheme 5. Initial
Previously, methods were reported for the cross coupling of
tertiary amines in the presence of Fe- and Cu-based oxidants.5,6
Also, metal free cross dehydrogenative coupling reactions of
tertiary amines using I2/O2 and eosin/visible light were also
reported.7 This simple alternative method involving activated
carbon for dehydrogenative cross coupling reactions has good
synthetic potential.
Scheme 5. Tentative Mechanism for Oxidative Coupling of
2-Naphtholate 19
We have also undertaken efforts toward the use of molecular
oxygen-doped carbon materials in oxidative coupling reactions.
We have performed the reaction of 2-naphthol 17a using 1 g of
oxygen-doped AC in solvents like THF, methanol, and toluene,
but only in toluene was the bi-2-naphthol 18a obtained in 25%
yield (Table 3, entry 1). When the reaction was performed in
the presence of t-BuOK as a base, the yield increased to 48%.
The yield further improved to 67% when the reaction with t-
BuOK was performed in THF, presumably because of the
greater solubility of t-BuOK in THF solvent. When 2 g of
deprotonation of the 2-naphthol 17a by t-BuOK base would
give the 2-naphtholate 19 that could transfer one electron to
the positively charged superoxide radical-bound carbon material
3 to give the naphtholate radical 21. Dimerization of this
naphtholate radical 21 followed by aromatization would give
the bi-2-naphthol product 18a (Scheme 5).
Table 3. Reaction of Molecular Oxygen-Adsorbed Carbon
a
Materials with 2-Naphthol Derivatives
The formation of paramagnetic species upon addition of 2-
naphthol and KOtBu was confirmed by EPR spectroscopy (S4,
1.8, Supporting Information). The coupled product 18a was
not formed when the reaction was performed in the presence of
TEMPO, indicating the expected TEMPO+ oxonium ion
intermediate formed in the reaction of TEMPO with oxygen-
doped activated carbon does not oxidize 2-naphtholate 19.
Previously, methods for oxidative coupling of 2-naphthol
were reported using FeCl3·6H2O and Cu−amine com-
plexes.8−10 Recently, Wang et al.11 reported the coupling of
2-naphthol using m-CPBA and FeCl3 as catalysts. Graphene
oxide-BF3-catalyzed oxidative coupling of electron rich
aromatics was also reported,12 but the preparation of such
graphene oxide requires harsh conditions compared to the
simple method for adsorption of O2 to prepare the oxygen-
doped activated carbon 3 reported here.
In summary, convenient methods have been developed for
practical use of molecular oxygen-doped, metal free, and
reusable carbon materials like activated carbon, carbon black,
and graphite. The reaction of activated carbon with Ph3P gave
Ph3PO in 54% yield. Whereas benzylamine and dibenzyl-
amine undergo oxidative cleavage to give benzaldehyde in 25−
30% yield, the reaction of N-aryl isoquinoline with oxygen-
doped carbon materials leads to the formation of the radical
cation intermediates that give the corresponding iminium ions
b
c
entry CM (g) SM (2 mmol) solvent (mL) product yield (%)
d
1
2
3
4
5
6
7
8
9
AC (1)
AC (1)
AC (1)
AC (2)
AC (2)
AC (2)
AC (2)
CB (2)
AC (2)
17a
17a
17a
17a
17b
17c
17a
17a
17a
toluene (15)
toluene (15)
THF (15)
THF (30)
THF (30)
THF (30)
THF (30)
THF (45)
THF (30)
18a
18a
18a
18a
18b
18c
18a
18a
18a
25
48
67
95
83
68
76
70
93
e
f
a
Reactions were performed at 25 °C for 48 h using 2 mmol of t-
BuOK. SM indicates starting material 2-napthol derivatives 17.
Product: bi-2-naphthol derivatives 18. t-BuOK was not used. The
reaction was performed for 24 h. The reaction was performed using
b
c
d
e
f
recovered and reoxidized activated carbon.
C
DOI: 10.1021/acs.joc.7b00405
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The Journal of Organic Chemistry
Note
phenyl tetrahydroisoquinoline (0.5 mmol) and a nucleophile (1
mmol) in DMSO. The reaction mixture was stirred for an additional
48 h. After that, 15 mL of EtOAc was added and the mixture stirred for
an additional 0.5 h. The reaction mixture was filtered and washed
several times with EtOAc and H2O. The organic layer was extracted
with EtOAc, washed with brine, and then dried over anhydrous
Na2SO4. The solvent was evaporated under vacuum, and the crude
mixture was chromatographed on silica gel using a hexane/ethyl
acetate (90:10) eluent to isolate the pure compound.
that in turn react with certain nucleophilic reagents to give the
corresponding addition products in 67−89% yield. Also, in the
presence of t-BuOK, 2-naphthol derivatives undergo oxidative
coupling reaction to give bi-2-naphthol derivatives in 68−95%
yield. The activated carbon could be recovered, redoped with
molecular oxygen, and reused for these organic transformations.
Further systematic studies of the reactions of the oxygen-doped
carbon materials with electron-donating organic compounds
are expected to lead to the discovery of several new organic
transformations.
1-(Nitromethyl)-2-phenyl-1,2,3,4-tetrahydroisoquinoline (7).
Brown solid: mp 92−94 °C (lit.5 89−90 °C); 0.119 g (89% yield);
1H NMR (400 MHz, CDCl3) δ 7.29−7.18 (m, 5H), 7.14−7.13 (d, J =
6.8 Hz, 1H), 6.98 (d, J = 8 Hz, 2H), 6.85 (t, J = 7.2 Hz, 1H), 5.55 (t, J
= 7 Hz, 1H), 4.95−4.85 (m, 1H), 4.59−4.54 (m, 1H), 3.79−3.59 (m,
2H), 3.21−3.05 (m, 1H), 2.87−2.78 (m, 1H); 13C{1H} NMR (100
MHz, CDCl3) δ 148.5, 135.3, 133.0, 130.0, 129.2, 128.2, 127.0, 126.7,
119.5, 115.2, 78.8, 58.2, 42.1, 26.5; IR (KBr) 3063, 3030, 2964, 2915,
1605, 1545, 1496, 1380, 1003, 899, 756 cm−1.
EXPERIMENTAL SECTION
■
General Information. N-Phenyl tetrahydroisoquinoline 6 was
prepared following a literature procedure.13 Melting points were
determined using a capillary point apparatus. IR (KBr) spectra were
recorded on a FT-IR spectrophotometer with polystyrene as a
reference. 1H NMR (400 MHz) and 13C{1H} NMR (100 MHz)
spectra were recorded with chloroform-d as a solvent and TMS as a
reference (δ = 0 ppm). The chemical shifts are expressed in δ
downfield from the signal of internal TMS. EPR spectra was recorded
in a spectrometer equipped with an EMX micro X source for X band
measurement using Xenon 1.1b.60 software provided by the
manufacturer. Activated carbon was heated at 200 °C under reduced
pressure (0.001 mmHg) in a vacuum oven and stored under dry
nitrogen. Toluene and THF were freshly distilled over sodium
benzophenone ketyl before use. Analytical thin layer chromatographic
tests were performed on glass plates (3 cm × 10 cm) coated with 250
μm silica gel-G and GF254 containing 13% calcium sulfate as a binder.
The spots were visualized by a short exposure to iodine vapor or UV
light. Column chromatography was performed using silica gel (100−
200 mesh).
1-(1H-Indol-3-yl)-2-phenyl-1,2,3,4-tetrahydroisoquinoline (8).14
1
Pale yellow solid: mp 175−177 °C; 0.103 g (75% yield); H NMR
(400 MHz, CDCl3) δ 7.85 (s, 1H), 7.60 (d, J = 8 Hz, 1H), 7.34−7.27
(m, 4H), 7.23−7.18 (m, 4H), 7.09−7.06 (m, 3H), 6.83 (t, J = 7.2 Hz,
1H), 6.62 (s, 1H), 6.22 (s, 1H), 3.68−3.65 (m, 2H), 3.15−3.07 (m,
1H), 2.88−2.81 (m, 1H); 13C{1H} NMR (100 MHz, CDCl3) δ 149.8,
137.5, 136.6, 135.6, 129.3, 128.9, 128.1, 126.7, 126.5, 125.8, 124.2,
122.1, 120.1, 119.7, 119.3, 118.2, 115.9, 111.1, 56.7, 42.3, 26.7; IR
(KBr) 3408, 3058, 2915, 2838, 1704, 1589, 1501, 1452, 1348, 1222,
932, 740 cm−1.
2-Phenyl-1,2,3,4-tetrahydroisoquinoline-1-carbonitrile (9). Pale
yellow solid: mp 94−96 °C (lit.7a 98−99 °C); 0.078 g (67% yield);
1H NMR (400 MHz, CDCl3) δ 7.42−7.38 (m, 2H), 7.35−7.26 (m,
4H), 7.13 (d, J = 8 Hz, 1H), 7.06 (t, J = 7.4 Hz, 1H), 5.55 (s, 1H),
3.83−3.78 (m, 1H), 3.55−3.48 (m, 1H), 3.23−3.14 (m, 1H), 3.02−
2.96 (m, 1H); 13C{1H} NMR (100 MHz, CDCl3) δ 148.4, 134.7,
129.6, 129.4, 128.8, 127.1, 126.9, 121.9, 117.8, 117.6, 53.2, 44.2, 28.6;
IR (KBr) 3041, 2926, 2838, 1742, 1600, 1496, 1463, 1375, 1205, 1145,
1030, 942, 745, 695 cm−1.
General Procedure for Reaction of Molecular Oxygen-
Doped Carbon Materials with Ph3P in the Presence of Benzoic
Acid. In a 50 mL RB flask, activated carbon (5 g) heated at 200 °C
under high vacuum (0.001 mmHg) for 2 h. After the RB flask was
cooled to room temperature under a nitrogen atmosphere, the
contents were saturated with dry air for 1 h. To this were added Ph3P
(2.62 g 10 mmol) and benzoic acid (1.221 g, 10 mmol) in THF. The
reaction mixture was stirred for a further 24 h. The reaction mixture
was filtered, and the organic layer was separated. The solvent was
evaporated under reduced pressure, and the crude product Ph3PO
was purified by silica gel column chromatography using hexane as an
2-Phenyl-3,4-dihydroisoquinolin-1(2H)-one (10). White solid: mp
76−78 °C (lit.15 83−89 °C); 0.080 g (72% yield); hexane/ethyl
1
acetate (80:20); H NMR (400 MHz, CDCl3) δ 8.18 (d, J = 7.6 Hz,
1H), 7.45−7.34 (m, 5H), 7.27 (t, J = 7 Hz, 3H), 4.01 (t, J = 6.4 Hz,
2H), 3.16 (t, J = 6.4 Hz, 2H); 13C{1H} NMR (100 MHz, CDCl3) δ
164.2, 143.1, 138.3, 132.0, 129.7, 128.9, 128.8, 127.2, 127.0, 126.3,
125.3, 49.4, 28.7; IR (KBr) 3063, 3041, 2964, 2931, 1660, 1599, 1490,
1408, 1325, 1254, 1029, 739, 690 cm−1.
1
eluent to give a white solid: 0.501 g, 54% yield; H NMR (400 MHz,
CDCl3) δ 7.67−7.62 (m, 1H), 7.52−7.48 (m, 1H), 7.43−7.40 (m,
1H); 13C{1H} NMR (100 MHz, CDCl3) δ 133.0, 132.1, 132.0, 131.9,
128.5, 128.4; 31P NMR (162 MHz, CDCl3) δ 29.3; IR (neat, cm−1)
3073, 3046, 1599, 1489, 1435, 1308, 1188, 1117, 1002.
General Procedure for Cross Dehydrogenative Coupling of
N-Phenyl Tetrahydroisoquinoline with Activated Carbon and
a TEMPO Radical Scavenger. In a 25 mL RB flask, activated carbon
(1 g) was heated at 200 °C under high vacuum (0.001 mmHg) for 2 h.
After the RB flask was cooled to room temperature under a nitrogen
atmosphere, the contents were saturated with dry air for 1 h. To this
was added TEMPO (1 mmol) in a DMSO (4 mL) solvent, and the
mixture was stirred for 1 h. Then, N-phenyl tetrahydroisoquinoline
(0.5 mmol) and nitromethane (1 mmol) were added. The reaction
mixture was stirred for an additional 48 h. After that, 15 mL of EtOAc
was added and the mixture stirred for an additional 0.5 h. The reaction
mixture was filtered and washed several times with EtOAc and H2O.
The organic layer was extracted with EtOAc, washed with brine, and
then dried over anhydrous Na2SO4. The solvent was evaporated under
vacuum, and the crude mixture was chromatographed on silica gel
using a hexane/ethyl acetate eluent to isolate pure compound 7 in 93%
yield. The reaction of activated carbon in the presence of TEMPO may
lead to the formation of activated carbon−TEMPO oxonium ion
paramagnetic species, which may lead to the formation of product 7.
General Procedure for Oxidative Coupling of 2-Naphthol
Derivatives with Activated Carbon. In a 50 mL RB flask, the 2-
naphthol (17a−17c) (2 mmol) was dissolved in THF (30 mL) under
a nitrogen atmosphere. To this was added t-BuOK (2 mmol), and the
contents were stirred for ∼1 h followed by addition of activated carbon
(2 g). The reaction mixture was stirred for an additional 48 h. The
General Procedure for Oxidation of Benzylamine Deriva-
tives with Activated Carbon. In a 25 mL RB flask, activated carbon
(1 g) was heated at 200 °C under high vacuum (0.001 mmHg) for 2 h.
After the RB flask was cooled to room temperature under a nitrogen
atmosphere, the contents were saturated with dry air for 1 h. To this
benzylamine were added derivatives (1 mmol) in a THF solvent. The
reaction mixture was stirred for a further 24 h. After that, the reaction
mixture was filtered and the organic layer was evaporated. Then the
NMR spectrum was recorded for the crude compound to show the
formation of both imine and benzaldehyde (S13, Supporting
Information). The crude reaction mixture was washed several times
with EtOAc and H2O. The organic layer extracts with EtOAc were
washed with brine and then dried over anhydrous Na2SO4. The
solvent was evaporated under vacuum, and the crude mixture was
chromatographed on silica gel using a hexane/ethyl acetate (90:10)
eluent to give pure benzaldehyde.
General Procedure for Cross Dehydrogenative Coupling of
N-Phenyl Tetrahydroisoquinoline Derivatives with Activated
Carbon. In a 25 mL RB flask, activated carbon (1 g) was heated at
200 °C under high vacuum (0.001 mmHg) for 2 h. After the RB flask
was cooled to room temperature under a nitrogen atmosphere, the
contents were saturated with dry air for 1 h. To this were added N-
D
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Note
reaction mixtures were filtered and washed several times with DCM
and H2O. The organic layer was extracted with DCM, washed with
brine, and then dried over anhydrous Na2SO4. The solvent was
evaporated under vacuum, and the crude mixture was chromato-
graphed on silica gel using a hexane/ethyl acetate (85:15) eluent to
isolate the pure compound.
material for 1 h. This oxygen-adsorbed activated carbon sample was
reused for synthetic transformations.
(4) Xue, D.; Long, Y.-Q. J. Org. Chem. 2014, 79, 4727.
(5) Li, Z.; Li, C.-J. J. Am. Chem. Soc. 2005, 127, 3672.
(6) (a) Ratnikov, M. O.; Xu, X.; Doyle, M. P. J. Am. Chem. Soc. 2013,
135, 9475. (b) Brzozowski, M.; Forni, J. A.; Savage, G. P.; Polyzos, A.
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Pitchaiah, A. J. Org. Chem. 2010, 75, 3916.
1,1′-Bi-2,2′-naphthol (18a). Colorless solid: 0.275 g (95% yield);
mp 217−219 °C (lit.11 216−218 °C); 1H NMR (400 MHz, CDCl3) δ
7.97−7.95 (d, J = 8 Hz, 2H), 7.90−7.88 (d, J = 8 Hz, 2H), 7.39−7.33
(m, 4H), 7.33−7.29 (m, 2H), 7.17−7.15 (d, J = 8 Hz, 2H), 5.09 (s,
2H); 13C{1H} NMR (100 MHz, CDCl3) δ 152.6, 133.4, 131.4, 129.4,
128.4, 127.5, 124.2, 124.0, 117.7, 110.8; IR (neat) 3484, 3402, 3040,
1621, 1599, 1517, 1468, 1386, 1325, 1271, 1221, 1183, 1145 cm−1.
6,6′-Dibromo-1,1′-bi-2,2′-naphthol (18b). Colorless solid: 0.372 g
(7) (a) Dhineshkumar, J.; Lamani, M.; Alagiri, K.; Prabhu, K. R. Org.
Lett. 2013, 15, 1092. (b) Hari, D. P.; Konig, B. Org. Lett. 2011, 13,
̈
3852.
(8) Ding, K.; Wang, Y.; Zhang, L.; Wu, Y.; Matsuura, T. Tetrahedron
1996, 52, 1005.
(9) Brussee, J.; Groenendijk, J. K. G.; te Koppele, J. M.; Jansen, A. S.
(83% yield); mp 198−200 °C (lit.11 200−202 °C); H NMR (400
1
A. Tetrahedron 1985, 41, 3313.
MHz, CDCl3) δ 8.06−8.04 (m, 2H), 7.91−7.87 (m, 2H), 7.41−7.35
(m, 4H), 6.98−6.94 (m, 2H), 5.04 (s, 2H); 13C{1H} NMR (100 MHz,
CDCl3) δ 152.9, 131.9, 130.8, 130.7, 130.5, 130.4, 125.8, 118.9,
118.02, 110.6; IR (neat) 3451, 1604, 1588, 1495, 1380, 1347, 1215,
1160, 1122 cm−1.
Dimethyl 2,2′-Dihydroxy-1,1′-binaphthyl-3,3′-dicarboxylate
(18c). Yellow solid: 0.275 g (68% yield); mp 284−286 °C (lit.11
285−287 °C); 1H NMR (400 MHz, CDCl3) δ 10.77 (s, 2H), 8.71 (s,
2H), 7.95−7.93 (m, 2H), 7.37−7.35 (m, 4H), 7.20−7.18 (m, 2H),
4.06 (s, 6H); 13C{1H} NMR (100 MHz, CDCl3) δ 170.6, 154.0, 137.2,
132.9, 129.8, 129.5, 127.2, 124.7, 124.0, 117.0, 114.1, 52.7; IR (neat)
3183, 2947, 1676, 1506, 1441, 1326, 1293, 1221, 1150, 1084 cm−1.
(10) Doussot, J.; Guy, A.; Ferroud, C. Tetrahedron Lett. 2000, 41,
2545.
(11) Wang, K.; Lu, M.; Yu, A.; Zhu, X.; Wang, Q. J. Org. Chem. 2009,
74, 935.
(12) Morioku, K.; Morimoto, N.; Takeuchi, Y.; Nishina, Y. Sci. Rep.
2016, 6, 25824.
(13) Tanoue, A.; Yoo, W.-J.; Kobayashi, S. Org. Lett. 2014, 16, 2346.
(14) Liu, P.; Zhou, C.-Y.; Xiang, S.; Che, C.-M. Chem. Commun.
2010, 46, 2739.
(15) Zhang, W.; Yang, S.; Shen, Z. Adv. Synth. Catal. 2016, 358, 2392.
ASSOCIATED CONTENT
* Supporting Information
■
S
The Supporting Information is available free of charge on the
ACS Publications website at DOI: 10.1021/acs.joc.7b00405.
Copies of the EPR, 1H NMR, and 13C{1H} NMR spectra
of the products (PDF)
AUTHOR INFORMATION
Corresponding Author
*E-mail: mpsc@uohyd.ac.in.
■
ORCID
Mariappan Periasamy: 0000-0001-6376-6589
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
We thank the DST-SERB for its support via a J. C. Bose
National Fellowship (SR/S2/JCB-33/2005) and Green Chem-
istry programs (SB/S5/GC-01/2014) and the CSIR-HRDG for
its support by a research grant (02/0176/14/EMR-II). We also
thank the DST for its support of the School of Chemistry under
the FIST and IRPHA programs, and support of the UGC under
UPE and CAS programs to the School of Chemistry is also
gratefully acknowledged. M.S., P.O.R., M.R., and G.A.R. thank
the CSIR and UGC (New Delhi) for research fellowships.
REFERENCES
■
(1) Sumanasekera, G. U.; Chen, G.; Takai, K.; Joly, J.; Kobayashi, N.;
Enoki, T.; Eklund, P. C. J. Phys.: Condens. Matter 2010, 22, 334208.
(2) Radovic, L. R.; Bockrath, B. J. Am. Chem. Soc. 2005, 127, 5917.
(3) Reuse of oxidized activated carbon. After the reaction with
activated carbon, the resulting carbon materials were filtered and
washed several times with organic solvents (THF followed by acetone)
to remove the trace amount of organic products. Then, the sample was
heated at 200 °C under high vacuum for 2 h and cooled to rt under
N2. The dry oxygen was adsorbed by passing it through the carbon
E
DOI: 10.1021/acs.joc.7b00405
J. Org. Chem. XXXX, XXX, XXX−XXX