Rh-Catalyzed Cyclization of 3-Aryloxycarbonyldiazonaphthoquinones for the Synthesis of β-Phenylnaphthalene Lactones and Formal Synthesis of Pradimicinone

Article abstract of DOI:10.1021/acs.joc.5b01251

In this study, we developed a novel method for the synthesis of β-phenylnaphthalene lactones. The diazo-transfer reactions of 2-azido-1,3-dimethylimidazolinium chlorides to 3-aryloxycarbonyl-1-naphthols proceeded smoothly to give corresponding 3-aryloxycarbonyldiazonaphthoquinones in high yields. These intermediates were further transformed to β-phenylnaphthalene lactones through a Rh-catalyzed intramolecular formal C-H insertion reaction. This method of lactone formation was efficiently applied to the formal total synthesis of pradimicinone.

Full text of DOI:10.1021/acs.joc.5b01251

Note
pubs.acs.org/joc
Rh-Catalyzed Cyclization of
3‑Aryloxycarbonyldiazonaphthoquinones for the Synthesis of
β‑Phenylnaphthalene Lactones and Formal Synthesis of
Pradimicinone
Mitsuru Kitamura,* Shuhei Takahashi, and Tatsuo Okauchi
Department of Applied Chemistry, Kyushu Institute of Technology, 1-1 Sensuicho, Tobata, Kitakyushu 804-8550 Japan
S
* Supporting Information
ABSTRACT: In this study, we developed a novel method for the synthesis of β-phenylnaphthalene lactones. The diazo-transfer
reactions of 2-azido-1,3-dimethylimidazolinium chlorides to 3-aryloxycarbonyl-1-naphthols proceeded smoothly to give
corresponding 3-aryloxycarbonyldiazonaphthoquinones in high yields. These intermediates were further transformed to β-
phenylnaphthalene lactones through a Rh-catalyzed intramolecular formal C−H insertion reaction. This method of lactone
formation was efficiently applied to the formal total synthesis of pradimicinone.
for the synthesis of natural products such as polyketides and
biaryl compounds.5−7 Although several synthetic methods have
been reported for the formation of β-phenylnaphthalene
lactones,8 the most efficient method involves the Pd-catalyzed
intramolecular biaryl coupling of halogenated aryl carboxylic
acid aryl esters.9 This reaction is even applicable for the
formation of bulky ortho-tetra-substituted biaryl bonds.
However, this method can occasionally encounter several
problems such as a limited accessibility of starting haloaryl
compounds, the reproducibility of the reaction, and the harsh,
high-temperature reaction conditions.
Herein, we report a new synthetic method for the formation
of β-phenylnaphthalene lactones 2 via a Rh-catalyzed intra-
molecular 6-membered cyclization of 3-aryloxycarbonyl-2-
diazonaphthoquinones 1 (Scheme 1). We also address the
application of this synthetic methodology to the formal
synthesis of pradimicinone.
h(II)-catalyzed intramolecular C−H insertion reactions
Rare an efficient synthetic method for the formation of 5-
membered carbocyclic/heterocyclic compounds.1 In the
particular case of diazocarbonyl compounds that do not have
the required C−H bond for the formation of 5-membered
rings, the various formed products are dependent on the
reaction conditions and substrates. For example, the Rh-
catalyzed reactions of N-benzyl-2-diazoacetamides give either a
4-membered C−H insertion product or a 7-membered ring
product. These reactions proceed through aromatic cyclo-
addition and a successive expansion of a phenyl ring (Buchner
̈
reaction).2 The formation of a 6-membered formal C−H
insertion product has also been reported for the Rh-catalyzed
reaction of 1-diazo-4-aryl-2-butanone via the Buchner reaction
̈
intermediate.3
β-Phenylnaphthalene lactones (6H-benzo[b]naphtho[2,3-d]-
pyran-6-one derivatives and 5H-benzo[d]naphtho[2,3-b]pyran-
5-one derivatives) are often found in bioactive natural products
(Figure 1).4 These compounds are widely used as intermediates
Diazonaphthoquinones 1 were readily prepared from the
corresponding naphthols 3 through a regioselective, one-step
Scheme 1. Rh-Catalyzed Synthesis of β-Phenylnaphthalene
Lactone 2 from 3-Aryloxycarbonyldiazonaphthoquinone 1
Received: June 3, 2015
Figure 1. Natural products with the β-phenylnaphthalene lactone.
© XXXX American Chemical Society
A
DOI: 10.1021/acs.joc.5b01251
J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Note
reaction. This was accomplished using our recently developed
diazo-transfer method with 2-azido-1,3-dimethylimidazolinium
chloride (ADMC), which was prepared by reacting 2-chloro-
1,3-dimethylimidazolinium chloride (DMC) and sodium azide
(Table 1).10,11 We reported that the addition of 15-crown-5
Table 2. Rh-Catalyzed Cyclization of 3-Aryloxycarbonyl-2-
diazonaphthoquinone 1a
a
Table 1. Synthesis of Diazonaphthoquinones 1 from 1-
a
Naphthols 3 by Diazo-Transfer with ADMC
b
run
Rh cat. (mol %)
solvent
conc (M)
2a (%)
1
2
3
4
5
Rh2(OAc)4 (3)
Rh2(OAc)4 (3)
Rh2(OAc)4 (3)
Rh2(OAc)4 (3)
Rh2(OAc)4 (3)
Rh2(OAc)4 (3)
Rh2(OAc)4 (3)
Rh2(OAc)4 (3)
Rh2(OAc)4 (3)
Rh2(OAc)4 (1.5)
benzene
benzene
benzene
benzene
(ClCH2)2
toluene
MeCN
DMF
0.1
53
63
72
79
63
75
0.06
0.03
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
c
6
d
7
0
run
Ar
X
3
1
yield (%)
e
8
0
f
1
4-t-BuC6H4
Ph
H
3a
3b
3c
3d
3e
3f
1a
1b
1c
1d
1e
1f
92
9
THF
0
2
H
97
10
11
12
benzene
benzene
benzene
77
92
g
3
4-MeC6H4
4-MeOC6H4
4-ClC6H4
4-s-BuC6H4
3-MeC6H4
3-MeOC6H4
3-ClC6H4
2-MeC6H4
2-MeOC6H4
2-ClC6H4
2-CO2MeC6H4
3,5-(MeO)2C6H3
1-naphthyl
Ph
H
97
Rh2(oct)4 (1.5)
h
4
H
quant
quant
86
Rh2(OCOCF3)4 (1.5)
5
5
H
a
The reaction was performed at 90 °C as the bath temperature.
6
H
b
c
d
Concentration of 1a. The reaction was performed at 110 °C. 1a
e
f
7
H
3g
3h
3i
1g
1h
1i
79
was recovered in 74% yield. 1a was recovered in 91% yield. 1a was
recovered in 89% yield. Rh2(OCOC7H15)4. 4 was obtained in 46%
g
h
8
H
94
9
H
84
yield.
10
11
12
13
14
15
16
17
18
H
3j
1j
97
H
3k
3l
1k
1l
97
be reduced to 1.5 mol % without affecting the yield of 2a (77%,
Run 10). The yield of 2a further increased to 92% when
Rh2(oct)4 was substituted for Rh2(OAc)4. Intermolecular C−H
insertion product 4 for benzene was mainly formed when
Rh2(OCOCF)3 was used (run 12).
H
79
H
3m
3n
3o
3p
3q
3r
1m
1n
1o
1p
1q
1r
83
H
97
H
47
Me
Ph
MeO
93
To explore the scope of the intramolecular cyclization of 3-
aryloxycarbonyldiazonaphthoquinone 1, we subjected various
diazonaphthoquinones 1 to optimized reaction conditions [1.5
mol % Rh2(oct)4 in benzene (0.01 M for 1) at reflux] (Table
3).
Ph
85
Ph
94
a
Reaction conditions: 3 and Et3N (2 equiv) were added to a solution
of ADMC [prepared by the reaction between DMC (1.9 equiv) and
NaN3 (1.6 equiv) in CH3CN at −20 °C for 1 h].
Phenyl ester 1b and para-monosubstituted phenyl esters 1c−
1f gave their corresponding cyclic compounds 2b−2f in good
yields. In the case of meta-monosubstituted phenyl esters 1g−
1i that have two potential reaction sites for the formation of a
6-membered ring, the C−C bond cyclization is favored at the
para position of the substituent R. This selectivity is because of
steric hindrance, which mainly affords 2g−2i with a small
amount of regioisomers 2′g and 2′h for the reactions of 1g and
1h, respectively. In the series of ortho-monosubstituted phenyl
esters 1j−1m, the generated products are dependent on the
ortho-substituent R. Cyclized products were obtained from
both 1j (R = Me) and 1k (R = CO2Me). Although 1l (R =
OMe) and 1m (R = Cl) were consumed in the reaction
conditions, no cyclized products were obtained. meta-
Dimethoxyphenyl ester 1n cyclized to 2n with a high yield.
Binaphthyl lactone 2o was obtained from 3-(1-naphthyl)-
oxycarbonyldiazonaphthoquinone 1o with a 47% yield.
The introduction of a methyl, phenyl, or methoxy substituent
at the 4-position to 3-aryloxycarbonyl-2-diazonaphthoquinone
efficiently increases both the yield of the diazo-transfer products
and reaction rate for the diazo-transfer conversion of ADMC to
naphthols. Although all 1-naphthols were originally believed to
be suitable for the diazo-transfer reaction in the presence of 15-
crown-5, 1-naphthols 3 presented in Table 1 were efficiently
transformed to their corresponding diazonaphthoquinones 1 in
high yields without 15-crown-5.
Initially, the Rh-catalyzed reactions were examined with
diazonaphthoquinone 1a under several reaction conditions
(Table 2).12 When the reaction was performed in the presence
of 3 mol % Rh2(OAc)4 in benzene (0.1 M for 1a) at reflux (90
°C as bath temperature), 1a was consumed after 1 h to give 2a
with a 53% yield (run 1). A lower concentration of 1a increases
the yield of 2a (runs 1−4), and 2a was obtained in 79% at 0.01
M (run 4). Nonpolar solvents were particularly suitable for
these reactions (runs 4−9), and benzene was determined to
give the best results (run 4). The amount of Rh2(OAc)4 could
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DOI: 10.1021/acs.joc.5b01251
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The Journal of Organic Chemistry
Note
a
Table 3. Rh-Catalyzed Cyclization of Various 3-
Aryloxycarbonyldiazonaphthoquinones 1
Scheme 2. Formal Synthesis of Pradimicinone
a
a
Reaction conditions: (a) 1-Ethyl-3-(3-(dimethylamino)propyl)-
carbodiimide (EDCl), N,N-dimethyl-4-aminopyridine, CH2Cl2, rt, 2
h (51%). (b) DMC (4.5 equiv), NaN3 (4.4 equiv), 15-crown-5 (30
mol %), CH3CN, −20 °C, 1 h: then 7, Et3N (2 equiv), THF, −30 °C,
6 h. (c) Rh2(oct)4, (1.5 mol %), benzene, reflux, 2.5 h. (d) NaBH4 (4.0
equiv), THF, MeOH, −45 °C, 4 h (3 steps 55%).
following transformations were conducted without further
purification of these compounds. In summary, triol 10 was
obtained with a 55% yield in 3 steps from 1-naphthol 7.
The plausible reaction mechanism for the Rh-catalyzed
cyclization of 3-aryl-2-diazonaphthoquinones 1 is shown in
Scheme 3. In the first step, the Rh(II) catalyst reacts with 1 to
form rhodium−carbene complex I, which can then form
lactone 2 via intermediate II. Intermediate II may be formed via
a
Reaction conditions: 1 (0.3 mmol), Rh2(oct)4 (1.5 mol %) in
benzene (30 mL) at reflux for 1 h.
Buchner reaction intermediates III and/or IV or a direct
̈
1 efficiently yielded the cyclized products, and 2p−2r were
obtained in high yields from their corresponding 4-substituted
diazonaphthoquinones 1p−1r.
intramolecular C−H insertion reaction of I.14,15 No formation
of cyclized product 2 from ortho-substituted 1l (R = OMe) and
1m (R = Cl) could be attributed to the formation of rhodium
ylide I′ and the successive decomposition.16
To demonstrate the efficiency of our newly developed
methodology for lactone formation, we addressed the synthesis
of a natural product. We previously achieved the synthesis of
pradimicinone via biaryl lactone 9 and diol 10.7 We then
attempted the synthesis of these intermediates with our newly
developed reaction sequence, which involves the diazo-transfer
reaction and Rh-catalyzed lactone formation (Scheme 2).
Polysubstituted ester 7 was synthesized through a con-
densation reaction of carboxylic acid 5 with phenol 6. The
diazo-transfer reaction of ADMC to polysubstituted 1-naphthol
7 afforded diazonaphthoquinone 8. As shown in Table 1, the
diazo-transfer reaction to 1 proceeded smoothly in the absence
of 15-crown-5, but the addition of 15-crown-5 at a low
temperature was essential for the diazo-transfer reaction of 7.13
The Rh-catalyzed cyclization of 8 and its subsequent reduction
from lactone 9 successfully afforded triol 10. Because diazo-
transfer product 8 and lactone 9 were rather unstable, their
We developed an efficient method for the synthesis of β-
phenylnaphthalene lactones from 3-aryloxycarbonyl-1-naph-
thols through a 2-step synthetic sequence that involves a (i)
diazo-transfer reaction with ADMC and (ii) Rh-catalyzed
cyclization of diazonaphthoquinones. This methodology can be
applied to the formal total synthesis of pradimicinone, which
demonstrates the wide applicability of our methodology for
polysubstituted substrates.
EXPERIMENTAL SECTION
General Methods. All reactions were carried out under a nitrogen
■
or argon atmosphere. NMR spectra were recorded in CDCl3 [TMS
1
(for H, δ = 0) or CDCl3 (for 13C, δ = 77.0) was used as an internal
1
1
standard] or DMSO-d6 [TMS (for H, δ = 0), DMSO (for H, δ =
2.5), or DMSO (for 13C, δ = 40.0) was used as an internal standard].
High-resolution mass spectra (HRMS) were obtained by an electron
C
DOI: 10.1021/acs.joc.5b01251
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The Journal of Organic Chemistry
Note
4-aminopyridine (DMAP) (44 mg, 0.36 mmol) in dichloromethane
(15 mL), N,N′-dicyclohexylcarbodiimide (1.91g, 9.27 mmol) was
added at 0 °C, and the mixture was stirred for 1.5 h at room
temperature. The mixture was filtered, and the solvent was removed in
vacuo. The crude materials were purified by recrystallization (hexane/
ethyl acetate) to give 4-methoxymethyl-2-naphthalenecarboxylic-4-
(tert-butyl)phenyl ester (2.16 g, 76% yield). 1H NMR (500 MHz,
CDCl3) δ 8.45 (s, 1H), 8.33 (dd, 1H, J = 8.3, 0.7 Hz), 7.97 (dd, 1H, J
= 7.4, 1.1 Hz), 7.75 (d, 1H, J = 1.4 Hz), 7.64 (ddd, 1H, J = 8.4, 6.9, 1.5
Hz), 7.59 (ddd, 1H, J = 8.1, 6.9, 1.3 Hz), 7.47−7.44 (m, 2H), 7.19−
7.17 (m, 2H), 5.48 (s, 2H), 3.57 (s, 3H), 1.35 (s, 9H). To a solution of
4-methoxymethyl-2-naphthalenecarboxylic-4-(tert-butyl)phenyl ester
(2.16 g, 5.92 mmol) in THF (10 mL), 6 M HCl (5 mL) was added
at 50 °C, and the mixture was stirred for 16 h. The mixture was
extracted three times with ethyl acetate. The combined extracts were
washed with brine and then dried over anhydrous sodium sulfate. The
solvent was removed in vacuo to afford crude compounds. The crude
materials were purified by flash column chromatography (silica gel:
hexane/ethyl acetate = 13/1) to give naphthol 3a (1.72 g, 90% yield)
as a white solid. IR (KBr) 3393, 2961, 1715, 1698, 1578, 1509, 1401,
1310, 1231, 1092 cm−1; 1H NMR (500 MHz, CDCl3) δ 8.39 (s, 1H),
8.26 (d, 1H, J = 8.3 Hz), 7.96 (d, 1H, J = 7.6 Hz), 7.64 (ddd, 1H, J =
8.3, 6.9, 1.4 Hz), 7.59 (ddd, 1H, J = 8.1, 6.9, 1.2 Hz), 7.54 (d, 1H, J =
1.4 Hz), 7.45 (dt, 2H, J = 8.8, 3.0 Hz), 7.17 (dt, 2H, J = 8.7, 3 Hz),
5.64 (s, 1H), 1.35 (s, 9H); 13C NMR (125 MHz, CDCl3) δ 165.5,
151.8, 148.8, 148.6, 133.8, 129.3, 127.9, 127.4, 127.0, 126.9, 126.4,
124.6, 122.0, 121.0, 107.7, 34.5, 31.4 ppm. Anal. Found: C, 78.73; H,
6.29%. Calcd for C21H20O3: C, 78.73; H, 6.29%; HRMS (EI+) m/z
[M]+ Calcd for C21H20O3 320.1412; found, 320.1408; mp 173−174
°C (dec).
Scheme 3. Possible Reaction Mechanism
Compounds 3b−3o were prepared in a manner similar to the
preparation of 3a (Table 4).
ionization (EI) method of ionization with a double focusing sector
detector. Column chromatography was performed on silica gel.
Materials. Benzene was distilled from P2O5 and stored over 4A
molecular sieves. Rh2(OAc)4 and Rh2(oct)4 were purchased from
suppliers and were used as received. Sodium azide was purchased from
a supplier and was used as received. Triethylamine was distilled from
KOH and stored over KOH.
Table 4. Preparation of 3b−3o
4-(tert-Butyl)phenyl 4-Hydroxy-2-naphthalenecarboxylate (3a).
To a solution of potassium carbonate (30.9 g, 224 mmol) and methyl
4-hydroxy-2-naphthalenecarboxylate (14.7 g, 146 mmol) in acetone
(110 mL), chloromehtyl methyl ether (11.8 g, 146 mmol) was added
at 0 °C, and the mixture was stirred for 2 h at room temperature. The
mixture was extracted three times with ethyl acetate. The combined
extracts were washed with brine and then dried over anhydrous
sodium sulfate. The solvent was removed in vacuo to afford crude
compounds. The crude materials were purified by flash column
chromatography (silica gel: hexane/ethyl acetate = 9/1) to give methyl
4-methoxymethyl-2-naphthalencarboxylate (20.3 g) as a yellow oil. 1H
NMR (400 MHz, CDCl3) δ 8.30−8.28 (m, 1H), 8.28 (d, 1H, J = 1.0
Hz), 7.92 (d, 1H, J = 7.7, 1.5 Hz), 7.64 (d, 1H, J = 8.3, 6.9, 1.4 Hz),
7.55 (ddd, 1H, J = 8.2, 6.8, 1.3 Hz), 5.45 (s, 2H), 3.97 (s, 3H), 3.56 (s,
3H); 13C NMR (100 MHz, CDCl3) δ 167.1, 152.8, 133.5, 129.1,
128.1, 127.7, 127.6, 127.0, 124.6, 122.0, 106.6, 94.7, 56.4, 52.2 ppm.
To a solution of methyl 4-methoxymethyl-2-naphthalencarboxylate
(20.3 g, 82.3 mmol) in methanol (50 mL), potassium hydroxide (10.8
g, 166 mmol) was added at room temperature, and the mixture was
stirred for 0.5 h at 80 °C. After cooling to 0 °C, the mixture was
acidified with 2 N HCl. The precipitates were collected by filtration to
afford crude compounds. The crude materials were purified by
recrystallization (hexane/ethyl) to give 4-methoxymethyl-2-naphtha-
lenecarboxylic acid (14.8 g, 78% yield) as a white solid. IR (KBr) 3457,
2950, 1684, 1580, 1463, 1426, 1371, 1303, 1155, 1057 cm−1; 1H NMR
(400 MHz, CDCl3) δ 8.38 (s, 1H), 8.32 (dd, 1H, J = 8.1, 0.7 Hz), 7.96
(dd, 1H, J = 7.4, 1.2 Hz), 7.70 (d, 1H, J = 1.3 Hz), 7.63 (ddd, 1H, J =
8.2, 6.8, 1.4 Hz), 7.58 (ddd, 1H, J = 8.1, 6.9, 1.3 Hz), 5.48 (s, 2H), 3.58
(s, 3H); 13C NMR (100 MHz, CDCl3) δ 171.6, 153.0, 133.4, 129.3,
128.6, 128.1, 127.2, 126.7, 125.7, 122.1, 106.7, 94.8, 56.5 ppm. To a
solution of 4-tert-butylphenol (1.33 g, 8.84 mmol), 4-methoxymethyl-
2-naphthalenecarboxylic acid (1.86 g, 8.00 mmol), and N,N-dimethyl-
run
Ar
first step (%)
second step (%)
1
Ph
quant
92
3b 78
3c 81
3d 57
3e 73
3f 72
3g 74
3h 72
3i 72
3j 84
3k 86
3l 73
3m 68
3n 52
3o 77
2
4-MeC6H4
3
4-MeOC6H4
4-ClC6H4
64
4
91
5
4-s-BuC6H4
3-MeC6H4
90
6
quant
quant
quant
quant
94
7
3-MeOC6H4
3-ClC6H4
8
9
2-MeC6H4
10
11
12
13
14
2-MeOC6H4
2-ClC6H4
quant
92
2-CO2MeC6H4
3,5-(MeO)2C6H3
1-naphthyl
90
92
4-Phenyl 4-Hydroxy-2-naphthalenecarboxylate (3b). White solid
(861 mg); IR (KBr) 3369, 1702, 1578, 1401, 1311, 1226, 1189 cm−1;
1H NMR (400 MHz, CDCl3) δ 8.40 (s, 1H), 8.26 (dd, 1H, J = 8.1, 0.3
Hz), 7.96 (d, 1H, J = 7.4, 1.2 Hz), 7.64 (ddd, 1H, J = 8.3, 6.9, 1.4 Hz),
7.59 (ddd, 1H, J = 8.1, 6.9, 1.2 Hz), 7.57 (dd, 1H. J = 1.4 Hz), 7.47−
7.43 (m, 2H), 7.31−7.25 (m, 3H), 5.82 (s, 1H); 13C NMR (100 MHz,
CDCl3) δ 165.7, 152.1, 150.9, 133.7, 129.5, 129.2, 127.9, 127.3, 127.2,
126.7, 126.0, 124.5, 122.1, 121.7, 107.6 ppm. Anal. Found: C, 76.98;
H, 4.62%. Calcd for C17H12O3: C, 77.26; H, 4.58%; mp 169−170 °C
(dec).
D
DOI: 10.1021/acs.joc.5b01251
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The Journal of Organic Chemistry
Note
4-Methylphenyl 4-Hydroxy-2-naphthalenecarboxylate (3c). Pale
yellow solid (882 mg); IR (KBr) 3441, 1721, 1508, 1402, 1308, 1276,
1221, 1199, 1064 cm−1; 1H NMR (400 MHz, CDCl3) δ 8.39 (s, 1H),
8.25 (d, 1H, J = 8.4 Hz), 7.96 (d, 1H, J = 7.4, 1.2 Hz), 7.64−7.56 (m,
3H), 7.24 (d, 2H, J = 8. Two Hz), 7.13 (dt, 2H, 6.4, J = 2.0 Hz), 5.88
(s, 1H), 2.38 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 166.0, 152.0,
148.6, 135.6, 133.7, 130.0, 129.2, 127.9, 127.3, 127.1, 126.8, 124.4,
122.1, 121.3, 107.7, 20.9 ppm; HRMS (EI+) m/z [M]+ Calcd for
C18H14O3 278.0943; found, 278.0941; mp 155−156 °C (dec).
4-Methoxyphenyl 4-Hydroxy-2-naphthalenecarboxylate (3d).
White solid (389 mg); IR (KBr) 3375, 1708, 1597, 1579, 1507,
134.8, 133.8, 130.3, 129.3, 128.2, 127.5, 127.2, 126.3, 126.2, 124.8,
122.4, 122.0, 120.2, 107.5 ppm. Anal. Found: C, 68.40; H, 3.75%.
Calcd for C17H1135ClO3: C, 68.35; H, 3.71%; mp 178−179 °C (dec).
2-Methylphenyl 4-Hydroxy-2-naphthalenecarboxylate (3j). Pale
yellow solid (887 mg); IR (KBr) 3452, 1715, 1597, 1583, 1403, 1310,
1
1278, 1228 cm−1; H NMR (400 MHz, CDCl3) δ 8.42 (s, 1H), 8.26
(d, 1H, J = 8.4 Hz), 7.97 (d, 1H, J = 7.5, 1.1 Hz), 7.64 (ddd, 1H, J =
8.4, 7.0, 1.6 Hz), 7.61−7.58 (m, 2H), 7.31−7.23 (m, 2H), 7.21−7.16
(m, 2H), 5.84 (s, 1H), 2.26 (s, 3H); 13C NMR (100 MHz, CDCl3) δ
165.6, 152.2, 149.5, 133.7, 131.2, 130.3, 129.2, 127.9, 127.3, 127.2,
127.0, 126.5, 126.2, 124.4, 122.1, 121.9, 107.7, 16.2 ppm; HRMS (EI+)
m/z [M]+ Calcd for C18H14O3 278.0943; found, 278.0950; mp 152−
153 °C (dec).
2-Methylphenyl 4-Hydroxy-2-naphthalenecarboxylate (3k). Pale
yellow solid (919 mg); IR (KBr) 3417, 1719, 1598, 1581, 1505, 1403,
1307, 1282, 1220 cm−1; 1H NMR (400 MHz, CDCl3) δ 8.42 (s, 1H),
8.25 (d, 1H, J = 8.2 Hz), 7.95 (d, 1H, J = 7.7 Hz), 7.64−7.55 (m, 3H),
7.29−7.24 (m, 1H), 7.20 (dd, 1H, J = 3.9, 1.4 Hz), 7.05−6.99 (m,
2H), 5.84 (s, 1H), 3.83 (s, 3H); 13C NMR (100 MHz, CDCl3) δ
165.4, 152.1, 151.3, 139.9, 133.7, 129.2, 127.8, 127.2, 127.1, 127.0,
126.5, 124.5, 122.9, 122.0, 120.9, 112.5, 107.9, 55.9 ppm. Anal. Found:
C, 73.26; H, 4.82%. Calcd for C18H14O4: C, 73.46; H, 4.79%; mp
159−160 °C (dec).
1
1402, 1311, 1277, 1230, 1197 cm−1; H NMR (500 MHz, CDCl3) δ
8.39 (s, 1H), 8.26 (d, 1H, J = 8.4 Hz), 7.96 (d, 1H, J = 7.9 Hz), 7.63
(ddd, 1H, J = 8.3, 6.9, 1.4 Hz), 7.57 (ddd, 1H, J = 8.1, 6.9, 1.2 Hz),
7.55 (d, 1H, J = 1.3 Hz), 7.17 (dt, 2H, J = 9.0, 2.3 Hz), 6.96 (dt, 2H, J
= 9.1, 2.3 Hz), 5.81 (s, 1H), 3.83 (s, 3H); 13C NMR (125 MHz,
CDCl3) δ 165.7, 157.3, 151.8, 144.5, 133.8, 129.2, 127.9, 127.4, 127.0,
126.8, 124.6, 122.4, 121.9, 114.6, 107.6, 55.6 ppm; HRMS (EI+) m/z
[M]+ Calcd for C18H14O4 294.0892; found, 294.0890; mp 184−185
°C (dec).
4-Chlorophenyl 4-Hydroxy-2-naphthalenecarboxylate (3e).
White solid (981 mg); IR (KBr) 3449, 1719, 1489, 1405, 1309,
1
1282, 1223 cm−1; H NMR (500 MHz, DMSO) δ 10.6 (s, 1H), 8.30
(s, 1H), 8.21 (dd, 1H, J = 7.7, 1.0 Hz), 8.11 (dd, 1H, J = 7.5, 1.6 Hz),
7.65 (ddd, 1H, J = 8.3, 6.8, 1.4 Hz), 7.63 (ddd, 1H, J = 8.3, 6.9, 1.4
Hz), 7.56 (d, 2H, J = 8.8 Hz), 7.48 (d, 1H, J = 1.5 Hz), 7.39 (d, 2H, J
= 8.8 Hz); 13C NMR (125 MHz, DMSO) δ 165.2, 154.2, 150.0, 133.9,
130.6, 130.0, 129.7, 128.2, 127.8, 127.6, 126.7, 124.4, 122.8, 122.5,
107.0 ppm; HRMS (EI+) m/z [M]+ Calcd for C17H1135ClO3 298.0397;
found, 298.0399; mp 184−185 °C (dec).
4-(sec-Butyl)phenyl 4-Hydroxy-2-naphthalenecarboxylate (3f).
White solid (778 mg); IR (KBr) 3397, 2963, 1704, 1578, 1508,
1401, 1271, 1228, 1186 cm−1; 1H NMR (500 MHz, CDCl3) δ 8.39 (s,
1H), 8.26 (d, 1H, J = 7.7 Hz), 7.96 (d, 1H, J = 7.6 Hz), 7.63 (ddd, 1H,
J = 8.3, 6.9, 1.4 Hz), 7.59 (ddd, 1H, J = 8.1, 6.9, 1.3 Hz), 7.56 (d, 1H, J
= 1.4 Hz), 7.25 (d, 2H, J = 7.9 Hz), 7.17 (d, 2H, J = 8.6 Hz), 5.76 (s,
1H), 2.68−2.61 (m, 1H), 1.65−1.58 (m, 2H), 1.26 (d, 3H, J = 6.9
Hz), 0.86 (t, 3H, J = 7.4 Hz); 13C NMR (100 MHz, CDCl3) δ 165.9,
152.1, 148.8, 145.4, 133.7, 129.2, 128.0, 127.8, 127.3, 127.1, 126.8,
124.4, 122.1, 121.3, 107.7, 41.1, 31.2, 21.8, 12.2 ppm; HRMS (EI+) m/
z [M]+ Calcd for C21H20O3 320.1412; found, 320.1408; mp 137−138
°C (dec).
2-Chlorophenyl 4-Hydroxy-2-naphthalenecarboxylate (3l). White
solid (913 mg); IR (KBr) 3445, 1721, 1597, 1581, 1477, 1403, 1309,
1280, 1220, 1067 cm−1; 1H NMR (500 MHz, DMSO) δ 10.7 (s, 1H),
8.34 (s, 1H), 8.22 (d, 1H, J = 7.9 Hz), 8.13 (d, 1H, J = 7.3 Hz), 7.68−
7.62 (m, 3H), 7.53−7.46 (m, 3H), 7.39 (ddd, 1H, J = 7.8, 7.4, 1.7 Hz);
13C NMR (125 MHz,DMSO) δ 164.5, 154.3, 147.3, 133.9, 130.6,
129.8, 129.1, 128.4, 128.3, 127.9, 127.7, 126.4, 126.2, 124.9, 122.9,
122.6, 106.9 ppm. Anal. Found: C, 68.21; H, 3.67%. Calcd for
C17H1135ClO3: C, 68.35; H, 3.71%; mp 197−198 °C (dec).
2-Methoxycarbonylphenyl 4-Hydroxy-2-naphthalenecarboxylate
(3m). Beige solid (863 mg); IR (KBr) 3405, 3056, 1707, 1604, 1579,
1484, 1404, 1305, 1278, 1226, 1087 cm−1; 1H NMR (500 MHz,
CDCl3) δ 8.41(s, 1H), 8.23(d, 1H, J = 8.3 Hz), 8.09(dd, 1H, J = 7.8,
1.7 Hz), 7.95(d, 1H, J = 7.5 Hz), 7.65−7.55(m, 4H), 7.38(ddd, 1H, J =
8.7, 7.7, 1.1 Hz), 7.28 (dd, 1H, J = 8.1, 1.0 Hz), 5.95 (s, 1H), 3.74 (s,
3H); 13C NMR (125 MHz, CDCl3) δ 165.5, 165.2, 151.9, 150.8,
133.9, 133.8, 131.9, 129.2, 127.8, 127.2, 127.1, 126.6, 126.1, 124.7,
123.9, 123.4, 122.0, 107.6, 52.3 ppm; HRMS (EI+) m/z [M]+ Calcd
for C19H14O5 322.0841; found, 322.0833; mp 169−170 °C (dec).
3,5-Dimethoxyphenyl 4-Hydroxy-2-naphthalenecarboxylate
(3n). White solid (603 mg); IR (KBr) 3425, 1707, 1622, 1590,
1476, 1406, 1305, 1271, 1218, 1191, 1153, 1058 cm−1; 1H NMR (400
MHz, CDCl3) δ 8.38 (s, 1H), 8.26 (d, 1H, J = 8.5 Hz), 7.96 (d, 1H, J =
8.0 Hz), 7.64 (ddd, 1H, J = 8.3, 6.9, 1.5 Hz), 7.59 (ddd, 1H, J = 8.1,
6.9, 1.3 Hz), 7.55 (d, 1H, J = 1.4 Hz), 6.43 (d, 2H, J = 2.2 Hz), 6.40 (t,
1H, J = 2.2 Hz), 5.90 (s, 1H), 3.80 (s, 6H); 13C NMR (100 MHz,
CDCl3) δ 165.5, 161.2, 152.4, 152.1, 133.7, 129.2, 127.9, 127.3, 127.1,
126.6, 124.4, 122.2, 107.6, 100.3, 98.5, 55.5 ppm; HRMS (EI+) m/z
[M]+ Calcd for C19H16O5 324.0998; found, 324.0993; mp 140−141
°C (dec).
3-Methylphenyl 4-Hydroxy-2-naphthalenecarboxylate (3g).
White solid (1.12 g); IR (KBr) 3448, 1722, 1582, 1402, 1307, 1277,
1
1215, 1146 cm−1; H NMR (400 MHz, CDCl3) δ 8.39 (s, 1H), 8.26
(d, 1H, J = 8.4 Hz), 7.96 (dd, 1H, J = 7.5, 1.2 Hz), 7.64 (ddd, 1H, J =
8.4, 6.9, 1.6 Hz), 7.59 (ddd, 1H, J = 8.1, 6.9, 1.3 Hz), 7.55 (d, 1H, J =
1.4 Hz), 7.33 (t, 1H, J = 7.7 Hz), 7.10 (d, 1H, J = 8.2 Hz), 7.06−7.04
(m, 2H), 5.78 (s, 1H), 2.40 (s, 3H); 13C NMR (100 MHz, CDCl3) δ
165.9, 152.1, 150.8, 139.7, 133.7, 129.26, 129.22, 127.8, 127.3, 127.2,
126.8, 126.7, 124.4, 122.2, 122.1, 118.6, 107.6, 21.3 ppm. Anal. Found:
C, 77.53; H, 5.12%. Calcd for C18H14O3: C, 77.68; H, 5.07%; mp
158−159 °C (dec).
Naphthalenyl 4-Hydroxy-2-naphthalenecarboxylate (3o). White
solid (375 mg); IR (KBr) 3429, 1719, 1404, 1388, 1280, 1218, 1078
cm−1; 1H NMR (400 MHz, CDCl3) δ 8.54 (s, 1H), 8.27 (dd, 1H, J =
8.4, 1.0 Hz), 8.00 (dd, 1H, J = 7.3, 1.3 Hz), 7.96 (dd, 1H, J = 7.9, 1.3
Hz), 7.91 (dd, 1H, J = 7.5, 2.1 Hz), 7.80 (d, 1H, J = 8.3 Hz), 7.66−
7.58 (m, 3H), 7.55−7.46 (m, 3H), 7.41 (dd, 1H, J = 7.5, 0.9 Hz), 5.87
(s, 1H); 13C NMR (125 MHz, DMSO-d6) δ 165.5, 154.3, 146.9, 134.7,
134.0, 129.8, 128.6, 128.3, 127.8, 127.7, 127.4, 127.2, 126.9, 126.7,
126.5, 126.3, 122.9, 122.6, 121.3, 119.2, 107.0 ppm; HRMS (EI+) m/z
[M]+ Calcd for C21H14O3 314.0943; found, 314.0936; mp 195−196
°C (dec);
Phenyl 4-Hydroxy-1-methyl-2-naphthalenecarboxylate (3p). To
a suspention of sodium hydride (60%, dispersion in mineral oil,
washed with hexane (4.28 g, 107 mmol)) in toluene (40 mL) was
added to dimethyl succinate (18.7 g, 128 mmol) and methanol (39.5
mg, 1.23 mmol) at 0 °C and was sttired for 15 min. A solution of
acetophenone (5.15g, 42.8 mmol) in toluene (10 mL) was added at 0
3-Methoxyphenyl 4-Hydroxy-2-naphthalenecarboxylate (3h).
White solid (1.09 g); IR (KBr) 3421, 1706, 1583, 1492, 1408, 1308,
1274, 1225, 1138 cm−1; 1H NMR (400 MHz, CDCl3) δ 8.39 (s, 1H),
8.26 (d, 1H, J = 8.5 Hz), 7.96 (d, 1H, J = 8.6 Hz), 7.64 (ddd, 1H, J =
8.3, 6.9, 1.6 Hz), 7.59 (ddd, 1H, J = 8.1, 6.9, 1.4 Hz), 7.55 (d, 1H, J =
1.4 Hz), 7.34 (t, 1H, J = 8.2 Hz), 6.87−6.81 (m, 3H), 5.77 (s, 1H),
3.83 (s, 3H); 13C NMR (125 MHz, DMSO-d6) δ 165.2, 160.7, 154.2,
152.2, 133.9, 130.5, 129.7, 128.1, 127.8, 127.5, 127.0, 122.6, 122.5,
114.5, 112.3, 108.4, 107.0, 55.9 ppm. Anal. Found: C, 73.16; H, 4.78%.
Calcd for C18H14O4: C, 73.46; H, 4.79%; mp 145−146 °C (dec).
3-Chlorophenyl 4-Hydroxy-2-naphthalenecarboxylate (3i). White
solid (966 mg); IR (KBr) 3434, 3062, 1703, 1585, 1471, 1404, 1308,
1
1269, 1066 cm−1; H NMR (500 MHz, CDCl3) δ 8.38 (s, 1H), 8.27
(d, 1H, J = 7.6 Hz), 7.96 (d, 1H, J = 7.6 Hz), 7.65 (ddd, 1H, J = 8.2,
6.7, 1.2 Hz), 7.60 (ddd, 1H, J = 8.2, 7.0, 1.2 Hz), 7.51 (d, 1H, J = 1.2
Hz), 7.38 (t, 1H, J = 8.2 Hz), 7.31−7.27 (m, 2H), 7.18−7.16 (m, 1H),
5.76 (s, 1H); 13C NMR (125 MHz, CDCl3) δ 164.9, 151.9, 151.5,
E
DOI: 10.1021/acs.joc.5b01251
J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Note
°C. The reaction mixture was warmed to room temperature, and the
stirring was continued overnight. The mixture was poured over ice and
stirred for 1 h at room temperature. The organic layer was extracted
three times with 1 M K2CO3 (aq), and the aqueous layer was washed
three times with ethyl acetate. The aqueous layer was acidified with
conc. HCl, and the organic layer was extracted three times with ethyl
acetate. The combined extracts were washed with water and brine and
then dried over anhydrous sodium sulfate. The solvent was removed in
vacuo to afford crude compounds. Sodium acetate (7.03 g, 85.7 mmol)
and acetic anhydride (100 mL) were added to this crude material at
room temperature. The reaction mixture was heated at reflux for 1.5 h.
After cooling to room temperature, the reaction was stopped by
adding water, and then, the solvent was removed in vacuo. The mixture
was extracted three times with ethyl acetate. The combined extracts
were washed with water and brine, and then dried over anhydrous
sodium sulfate. The solvent was removed in vacuo to afford crude
compounds. The crude materials were purified by flash column
chromatography (silica gel: hexane/ethyl acetate = 9/1) to give methyl
4-acetyloxy-1-methyl-2-naphthalenecarboxylate (4.67 g, 42% yield) as
(m, 1H), 7.64−7.60 (m, 2H), 7.46−7.42 (m, 3H), 7.41 (s, 1H), 7.30−
7.27 (m, 1H), 7.24 (dd, 1H, J = 7.5, 2.0 Hz), 5.50 (s, 1H), 2.94 (s,
3H); 13C NMR (125 MHz, CDCl3) δ 166.8, 150.9, 149.5, 134.2,
131.2, 129.5, 127.17, 127.15, 126.4, 126.1, 125.9, 125.5, 122.2, 121.7,
108.3, 15.4 ppm; HRMS (EI+) m/z [M]+ Calcd for C18H14O3
278.0943; found, 278.0934; mp 146−147 °C (dec).
Phenyl 4-Hydroxy-1-phenyl-2-naphthalenecarboxylate (3q).
Compound 3q was synthesized in 32% yield (1.23 g) as a white
solid from benzophenone instead of acetophenone similar to the
preparation of 3p. IR (KBr) 3421, 3074, 2962, 2923, 1731, 1698, 1595,
1491, 1380, 1303, 1240, 1189, 1074; 1H NMR (500 MHz, DMSO-d6)
δ 10.7 (s, 1H), 8.29 (d, 1H, J = 8.2 Hz), 7.62 (ddd, 1H, J = 8.2, 6.7, 1.2
Hz), 7.54−7.44 (m, 5H), 7.37−7.33 (m, 5H), 7.21 (t, 1H, J = 7.4 Hz),
6.77 (dd, 2H, J = 8.5, 0.9 Hz); 13C NMR (125 MHz, DMSO-d6) δ
167.1, 153.4, 150.7, 139.1, 133.5, 131.8, 130.6, 129.8, 128.6, 128.3,
127.8, 127.7, 127.3, 127.1, 126.5, 126.3, 122.6, 121.8, 107.3 ppm;
HRMS (EI+) m/z [M]+ Calcd for C23H16O3 340.1099; found,
340.1100; mp 188−189 °C (dec).
Phenyl 4-Hydroxy-1-methoxy-2-naphthalenecarboxylate (3r). To
a solution of phenyl 1,4-dihydroxy-2-naphthoate (840 mg, 3.00 mmol)
in dichloromethane (15 mL), pyridinium p-toluenesulfonate (PPTS)
(73.6 mg, 0.293 mmol) and 3,4-dihydro-2H-pyrane (DHP) (716 mg,
8.51 mmol) were added, and the mixture was stirred for 1 day at room
temperature. The mixture was washed with sat. NaHCO3 (aq) and
then dried over anhydrous sodium sulfate. The solvent was removed in
vacuo. The crude materials were purified by flash column
chromatography (silica gel: hexane/ethyl acetate = 98/2) to give
phenyl 4-tetrahydro-2H-pyranyloxy-1-methoxy-2-naphthalenecarboxy-
late (727 mg, 67%). To a solution of phenyl 4-tetrahydro-2H-
pyranyloxy-1-hydroxy-2-naphthalenecarboxylate (727 mg, 2.00 mmol)
and potassium carbonate (829 mg, 6.00 mmol) in dimethoxyethane
(DME) (5 mL), dimethyl sulfate (266 mg, 2.11 mmol) was added at
room teperature, and the mixture was stirred for 5 h at reflux. After
cooling to room temperature, the reaction was stopped by adding
Et3N. The mixture was filtered through a Celite pad (washed with
ethyl acetate). The solvent was removed in vacuo to afford crude
compounds. Acetic acid (4 mL), THF (2 mL), and water (1 mL) were
added to this crude material at room temperature. The mixture was
stirred for 7 h at 45 °C. The mixture was extracted three times with
ethyl acetate. The combined extracts were washed with brine and then
dried over anhydrous sodium sulfate. The mixture was washed with
sat. NaHCO3 (aq) and then dried over anhydrous sodium sulfate. The
solvent was removed in vacuo. The crude materials were purified by
flash column chromatography (silica gel: hexane/ethyl acetate = 9/1)
to give naphthol 3r (376 mg, 64% yield) as a yellow solid; IR (KBr)
3394, 1733, 1627, 1597, 1477, 1375, 1303, 1266, 1193, 1141, 1066; 1H
NMR (500 MHz, CDCl3) δ 8.27 (dd, 1H, J = 6.8, 1.6 Hz), 8.22 (dd,
1H, J = 6.9, 1.6 Hz), 7.66−7.59 (m, 2H), 7.46−7.42 (m, 2H), 7.39 (s,
1H), 7.30−7.23 (m, 3H), 5.66 (s, 1H), 4.07 (s, 3H); 13C NMR (125
MHz, CDCl3) δ 164.5, 153.1, 150.8, 147.6, 129.54, 129.50, 128.1,
127.2, 125.9, 123.7, 122.3, 121.7, 117.9, 108.9, 108.0, 63.6 ppm;
HRMS (EI+) m/z [M]+ Calcd for C18H14O4 294.0892; found,
294.0896; mp 146 °C (dec).
1
a yellow solid. H NMR (500 MHz, CDCl3) δ 8.24−8.21 (m, 1H),
7.90−7.86 (m, 1H), 7.65 (s, 1H), 7.63−7.59 (m, 2H), 3.94 (s, 3H),
2.94 (s, 3H), 2.46 (s, 3H); 13C NMR (125 MHz, CDCl3) δ 169.4,
168.1, 144.5, 135.9, 134.0, 128.2, 127.9, 127.1, 127.0, 125.8, 121.5,
118.2, 52.2, 20.9, 15.6 ppm. To a solution of methyl 4-acetyloy-1-
methyl-2-naphthalenecarboxylate (513 mg, 1.98 mmol) in methanol
(3 mL), potassium hydroxide (454 mg, 8.09 mmol) was added at
room temperature, and the mixture was stirred for 2 h at 80 °C. After
cooling to room temperature, the mixture was diluted with water and
then washed with Et2O. After the aqueous layer was acidified with 2 M
HCl (aq), the organic material was extracted three times with ethyl
acetate. The combined extracts were washed with water and brine and
then dried over anhydrous sodium sulfate. The solvent was removed in
vacuo to afford crude compounds. N,N-Dimethyl-4-aminopyridine
(24.0 mg, 0.196 mmol), acetic anhydride (604 mg, 5.92 mmol), and
pyridine (3 mL) were added to this crude material at 0 °C. The
reaction mixture was stirred at room temperature for 4 h. The reaction
was quenched with water, and the aqueous layer was acidified with 2
M HCl (aq). The organic materials were extracted three times with
ethyl acetate. The combined extracts were washed with water and
brine and then dried over anhydrous sodium sulfate. The solvent was
removed in vacuo to afford crude compounds. The crude materials
were purified by flash column chromatography (silica gel: chloroform/
methanol = 99/1) to give 4-acetyloxy-1-methyl-2-naphthalenecarbox-
ylic acid (405 mg, 84% yield). 1H NMR (500 MHz, acetone-d6) δ 11.5
(s, 1H), 8.35−8.31 (m, 1H), 8.03−7.99 (m, 1H), 7.71−7.66 (m, 3H),
2.96 (s, 3H), 2.47 (s, 3H). To a solution of phenol (163 mg, 1.73
mmol), 4-acetyloxy-1-methyl-2-naphthalenecarboxylic acid (404 g,
1.65 mmol) and N,N-dimethyl-4-aminopyridine (DMAP) (16.7 mg,
0.136 mmol) in dichloromethane (8 mL), N,N′-dicyclohexylcarbodii-
mide (391 mg, 1.89 mmol) was added at 0 °C, and the mixture was
stirred for 1.5 h at room temperature. The mixture was filtered, and
the solvent was removed in vacuo. The crude materials were purified
by flash column chromatography (silica gel: hexane/ethyl acetate = 7/
1) to give phenyl 4-acetyloxy-1-methyl-2-naphthalenecarboxylate (452
Typical Procedure for the Preparation of Diazonaphthoquinone
1. Synthesis of 1b. To a solution of 2-chloro-1,3-dimethylimidazo-
linium chloride (477 mg, 2.82 mmol) in acetonitrile (3 mL), sodium
azide (228.6 mg, 3.52 mmol) was added at −20 °C, and the mixture
was stirred for 1 h. Naphthol 3b (477.3 mg, 1.81 mmol) and
triethylamine (0.5 mL, 3.58 mmol) in THF (18 mL) were added to
the mixture, which was stirred for 30 min. The reaction was quenched
with water, and organic materials were extracted three times with ethyl
acetate. The combined extracts were washed with water and brine, and
then dried over anhydrous sodium sulfate. The solvent was removed in
vacuo to afford crude compounds. The crude materials were purified
by flash column chromatography (silica gel: hexane/ethyl acetate = 4/
1) to give diazonaphthoquinone 1b (508 mg, 97%).
1
mg, 86% yield). H NMR (500 MHz, CDCl3) δ 8.17−8.16 (m, 1H),
7.90−7.86 (m, 2H), 7.60−7.54 (m, 2H), 7.42−7.37 (m, 2H), 7.26−
7.22 (m, 3H), 2.96 (s, 3H), 2.42 (s, 3H); 13C NMR (125 MHz,
CDCl3) δ 169.5, 165.8, 150.8, 144.7, 137.4, 134.0, 129.4, 128.5, 128.3,
127.2, 126.0, 121.7, 121.5, 120.3, 118.4, 115.1, 20.9, 15.7 ppm. To a
solution of phenyl 4-acetyloxy-1-methyl-2-naphthalenecarboxylate
(445 mg, 1.39 mmol) in acetone (10 mL), 3 M HCl (5 mL) was
added at 70 °C, and the mixture was stirred for 4 h. The mixture was
extracted three times with ethyl acetate. The combined extracts were
washed with sat. NaHCO3 (aq) and brine and then dried over
anhydrous sodium sulfate. The solvent was removed in vacuo to afford
crude compounds. The crude materials were purified by flash column
chromatography (silica gel: hexane/ethyl acetate = 13/1) to give
naphthol 3p (346 mg, 89% yield) as a pale yellow solid. IR (KBr)
3394, 1706, 1597, 1491, 1382, 1355, 1287, 1212, 1165, 1143, 1085,
1068; 1H NMR (500 MHz, CDCl3) δ 8.28−8.25 (m, 1H), 8.21−8.17
4-(tert-Butyl)phenyl 3-diazo-3,4-dihydro-4-oxo-2-naphthalene-
carboxylate (1a). Orange solid; 92% yield (1.71 g); IR (KBr) 3070,
2963, 2105, 1716, 1615, 1577, 1510, 1431, 1308, 1220 cm−1; 1H NMR
(500 MHz, CDCl3) δ 8.42 (dd, 1H, J = 7.9 Hz), 7.70−7.75 (m, 3H),
F
DOI: 10.1021/acs.joc.5b01251
J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Note
7.65 (ddd, 1H, J = 8.3, 6.7, 1.8 Hz), 7.47 (d, 2H, J = 8.9 Hz), 7.15 (d,
2H, J = 8.6 Hz), 1.35 (s, 9H); 13CNMR (125 MHz, CDCl3) δ 179.1,
162.4, 149.5, 147.9, 134.6, 133.0, 131.1, 130.0, 129.9, 126.6, 125.8,
124.0, 120.7, 118.6, 34.6, 31.4 ppm. Anal. Found: C, 72.49; H, 5.24; N,
8.13%. Calcd for C21H18N2O3: C, 72.82; H, 5.24; N, 8.09%; mp 162−
163 °C (dec).
113.5, 112.3, 107.5, 55.5 ppm; HRMS (EI+) m/z [M]+ Calcd for
C18H12N2O4 320.0797; found, 320.0804; mp 144−145 °C (dec).
3-Chlorophenyl 3-Diazo-3,4-dihydro-4-oxo-2-naphthalenecar-
boxylate (1i). Yellow solid; 84% yield (537 mg); IR (KBr) 2105,
1714, 1624, 1588, 1476, 1428, 1310, 1232 cm−1; 1H NMR (400 MHz,
CDCl3) δ 8.42 (dd, 1H, J = 7.9, 0.6 Hz), 7.69−7.77 (m, 3H), 7.66
(ddd, 1H, J = 8.3, 6.8, 1.6 Hz), 7.40 (t, 1H, J = 8.0 Hz), 7.29−7.33 (m,
2H), 7.16 (dq, 1H, J = 8.1, 1.0 Hz); 13CNMR (100 MHz, CDCl3) δ
179.0, 161.7, 150.6, 135.0, 134.4, 133.0, 131.2, 130.4, 130.2, 130.1,
126.8, 125.8, 124.4, 122.1, 119.8, 117.9 ppm; HRMS (EI+) m/z [M]+
Calcd for C17H935ClN2O3 324.0302; found, 324.0307; mp 152−153
°C (dec).
2-Methylphenyl 3-Diazo-3,4-dihydro-4-oxo-2-naphthalenecar-
boxylate (1j). Orange solid; 97% yield (592 mg); IR (KBr) 3060,
2111, 1720, 1619, 1577, 1488, 1427, 1321, 1301 cm−1; 1H NMR (400
MHz, CDCl3) δ 8.43 (d, 1H, J = 8.0 Hz), 7.77 (s, 1H) 7.76−7.72 (m,
2H), 7.65 (ddd, 1H, J = 8.3, 6.5, 2.0 Hz), 7.32−7.21 (m, 3H), 7.15
(dd, 1H, J = 7.9, 1.3 Hz), 2.27 (s, 3H); 13CNMR (125 MHz, CDCl3) δ
179.0, 161.9, 148.9, 134.5, 132.9, 131.4, 131.1, 130.08, 130.06, 130.0,
127.2, 126.7, 125.8, 124.0, 121.7, 118.3, 16.2 ppm; HRMS (EI+) m/z
[M]+ Calcd for C18H12N2O3 304.0848; found, 304.0838; mp 169−170
°C (dec).
2-Methoxyphenyl 3-Diazo-3,4-dihydro-4-oxo-2-naphthalenecar-
boxylate (1k). Orange solid; 97% yield (623 mg); IR (KBr) 3069,
2944, 2102, 1716, 1586, 1577, 1488, 1427, 1321, 1301 cm−1; 1H NMR
(400 MHz, CDCl3) δ 8.42 (dd, 1H, J = 7.9, 0.5 Hz), 7.76 (s, 1 H),
7.75−7.69 (m, 2H), 7.64 (ddd, 1H, J = 8.3, 6.5, 2.0 Hz), 7.29 (ddd,
1H, J = 8.3, 7.6, 1.7 Hz), 7.18 (dd, 1H, J = 7.9, 1.6 Hz), 7.00−7.06 (m,
2H), 3.85 (s, 3H); 13CNMR (125 MHz, CDCl3) δ 179.1, 161.7, 151.0,
139.2, 134.6, 132.9, 131.1, 130.0, 129.9, 127.5, 125.7, 124.2, 122.7,
120.9, 118.3, 112.5, 55.9 ppm; HRMS (EI+) m/z [M]+ Calcd for
C18H12N2O4 320.0797; found, 320.0803; mp 153−154 °C (dec).
2-Chlorophenyl 3-Diazo-3,4-dihydro-4-oxo-2-naphthalenecar-
boxylate (1l). Orange solid; 79% yield (515 mg); IR (KBr) 3071,
2113, 1728, 1621, 1574, 1475, 1430, 1307 cm−1; 1H NMR (400 MHz,
CDCl3) δ 8.42 (dd, 1H, J = 7.8, 0.4 Hz), 7.81 (s, 1H), 7.75−7.69 (m,
2H), 7.66 (ddd, 1H, J = 8.1, 6.3, 2.2 Hz), 7.53 (dd, 1H, J = 7.5, 1.5
Hz), 7.37 (ddd, 1H, J = 8.3, 7.3, 1.6 Hz), 7.31−7.26 (m, 2H);
13CNMR (100 MHz, CDCl3) δ 179.0, 161.3, 146.5, 134.5, 133.0,
Phenyl 3-Diazo-3,4-dihydro-4-oxo-2-naphthalenecarboxylate
(1b). Orange solid; 97% yield (508 mg); IR (KBr) 2104, 1715,
1619, 1430, 1306, 1214, 1190, 1001 cm−1; 1H NMR (400 MHz,
CDCl3) δ 8.42 (dd, 1H, J = 7.9, 0.5 Hz), 7.76 (s, 1H), 7.79−7.70 (m,
2H), 7.65 (ddd, 1H, J = 8.3, 6.6, 1.8), 7.49−7.45 (m, 2H), 7.35−7.31
(m, 1H), 7.25−7.23 (m, 2H); 13CNMR (100 MHz, CDCl3) δ 179.0,
162.1, 150.2, 134.5, 132.9, 131.1, 130.0, 129.7, 126.5, 125.7, 124.1,
121.4, 121.4, 118.6 ppm; HRMS (EI+) m/z [M]+ Calcd for
C17H10N2O3 290.0691; found, 290.0684; mp 137−138 °C (dec).
4-Methylphenyl 3-Diazo-3,4-dihydro-4-oxo-2-naphthalenecar-
boxylate (1c). Yellow solid; 97% (592 mg); IR (KBr) 2107, 1720,
1616, 1577, 1507, 1432, 1308, 1220 cm−1; 1H NMR (400 MHz,
CDCl3) δ 8.41 (dd, 1H, J = 8.0, 0.6 Hz), 7.73−7.70 (m, 3H), 7.64
(ddd, 1H, J = 8.1, 6.7, 1.7 Hz), 7.25 (d, 2H, J = 8.2 Hz), 7.11 (d, 2H, J
= 8.5 Hz), 2.39 (s, 3H); 13CNMR (100 MHz, CDCl3) δ 179.0, 162.3,
148.0, 136.2, 134.5, 132.9, 131.0, 130.1, 130.0, 129.9, 125.7, 123.9,
121.0, 118.4, 20.8 ppm; HRMS (EI+) m/z [M]+ Calcd for
C18H12N2O3 304.0848; found, 304.0859; mp 119−120 °C (dec).
4-Methoxyphenyl 3-Diazo-3,4-dihydro-4-oxo-2-naphthalenecar-
boxylate (1d). Orange solid; quant (339 mg); IR (KBr) 2103, 1712,
1
1621, 1509, 1428, 1305, 1238 cm−1; H NMR (400 MHz, CDCl3) δ
8.42 (dd, 1H, J = 7.4, 0.5 Hz)7.76−7.69 (m, 3H), 7.65 (ddd, 1H, J =
8.3, 6.5, 1.8 Hz), 7.15 (dt, 2H, J = 9.1, 3.7 Hz), 6.97 (dt, 2H, J = 9.1,
3.6 Hz), 3.83 (s, 3H); 13CNMR (100 MHz, CDCl3) δ 179.0, 162.5,
157.7, 143.6, 134.5, 132.9, 131.0, 130.0, 129.9, 125.7, 123.9, 122.1,
118.4, 114.7, 55.6 ppm; HRMS (EI+) m/z [M]+ Calcd for
C18H12N2O4 320.0797; found, 320.0790; mp 138−139 °C (dec).
4-Chlorophenyl 3-Diazo-3,4-dihydro-4-oxo-2-naphthalenecar-
boxylate (1e). Yellow solid; quant (690 mg); IR (KBr) 2110, 1719,
1
1632, 1490, 1431, 1305, 1236 cm−1; H NMR (400 MHz, CDCl3) δ
8.42 (dd, 1H, J = 7.3, 0.6 Hz), 7.76−7.69 (m, 3H), 7.66 (ddd, 1H, J =
8.0, 6.8, 1.6 Hz), 7.43 (dt, 2H, J = 8.8, 2.1 Hz), 7.19 (dt, 2H, J = 8.9,
2.2 Hz); 13CNMR (100 MHz, CDCl3) δ 178.9, 161.9, 148.6, 134.9,
133.0, 132.0, 131.1, 130.1, 130.0, 129.7, 125.8, 124.3, 122.8, 118.0
ppm; HRMS (EI+) m/z [M]+ Calcd for C17H935ClN2O3 324.0296;
found, 324.0303; mp 150−151 °C (dec).
4-(sec-Butyl)phenyl 3-Diazo-3,4-dihydro-4-oxo-2-naphthalene-
carboxylate (1f). Orange solid; 86% yield (466 mg); IR (KBr)
3067, 2960, 2105, 1716, 1616, 1577, 1508, 1431, 1304, 1218 cm−1; 1H
NMR (400 MHz, CDCl3) δ 8.42 (dd, 1H, J = 7.4, 0.5 Hz), 7.70−7.76
(m, 3H), 7.64 (ddd, 1H, J = 8.3, 7.7, 1.8 Hz), 7.26 (d, 2H, J = 8.5 Hz),
7.15 (d, 2H, J = 8.5 Hz), 2.65 (q, 1H, J = 7.0 Hz), 1.61 (q, 2H, J = 7.3
Hz), 1.26 (d, 3H, J = 6.9 Hz), 0.85 (t, 3H, J = 7.3 Hz); 13CNMR (100
MHz, CDCl3) δ 179.1, 162.3, 148.1, 146.0, 134.5, 132.9, 131.0, 130.0,
129.9, 128.2, 125.7, 124.0, 120.9, 118.5, 41.2, 31.2, 21.8, 12.2 ppm;
HRMS (EI+) m/z [M]+ Calcd for C21H18N2O3 346.1312; found,
346.1317; mp 147−148 °C (dec).
3-Methylphenyl 3-Diazo-3,4-dihydro-4-oxo-2-naphthalenecar-
boxylate (1g). Orange solid; 79% yield (447 mg); IR (KBr) 3064,
2098, 1715, 1617, 1583, 1448, 1430, 1307, 1213 cm−1; 1H NMR (400
MHz, CDCl3) δ 8.42 (dd, 1H, J = 7.9, 0.6 Hz), 7.69−7.76 (m, 3H),
7.64 (ddd, 1H, J = 8.2, 6.7, 1.7 Hz), 7.34 (t, 1H, J = 7.7 Hz), 7.13 (d,
1H, J = 7.6 Hz), 7.05−7.02 (m, 2H), 2,41 (s, 3H); 13CNMR (100
MHz, CDCl3) δ 179.0, 162.2, 150.2, 140.0, 134.5, 132.9, 131.0, 130.0,
129.9, 129.4, 127.3, 125.7, 124.0, 121.9, 118.5, 118.3, 21.3 ppm;
HRMS (EI+) m/z [M]+ Calcd for C18H12N2O3 304.0848; found,
304.0849; mp 139−140 °C (dec).
3-Methoxyphenyl 3-Diazo-3,4-dihydro-4-oxo-2-naphthalenecar-
boxylate (1h). Yellow solid, 94% yield (604 mg); IR (KBr) 2114,
1717, 1618, 1489, 1427, 1301, 1212 cm−1; 1H NMR (400 MHz,
CDCl3) δ 8.42 (dd, 1H, J = 8.0, 0.6 Hz), 7.76−7.69 (m, 3H), 7.65
(ddd, 1H, J = 8.3, 6.7, 1.8 Hz), 7.36 (t, 1H, J = 8.2 Hz), 6.78−6.88 (m,
3H), 3.84 (s, 3H); 13CNMR (100 MHz, CDCl3) δ 179.0, 162.0, 160.7,
151.2, 134.4, 132.9, 131.0, 130.1, 130.03, 130.00, 125.7, 124.1, 118.3,
131.198, 130.197, 130.5, 130.19, 130.17, 128.0, 127.7, 126.8, 125.8,
124.7, 123.6, 117.6 ppm; HRMS (EI+) m/z [M]+ Calcd for
C17H935ClN2O3 324.0302; found, 324.0317; mp 184−185 °C (dec).
2-Methoxycarbonylphenyl 3-Diazo-3,4-dihydro-4-oxo-2-naph-
thalenecarboxylate (1m). Orange solid; 83% yield (288 mg); IR
1
(KBr) 2102, 1718, 1625, 1429, 1305, 1268, 1219, 1084 cm−1; H
NMR (400 MHz, CDCl3) δ 8.43 (dd, 1H, J = 7.8, 0.5 Hz), 8.12 (dd,
1H, J = 7.9, 1.6 Hz), 7.77 (s, 1H), 7.76−7.62 (m, 4H), 7.42 (ddd, 1H,
J = 7.7, 6.6, 1.1 Hz), 7.27 (dd, 1H, J = 7.9, 1.1 Hz), 3.83 (s, 3H);
13CNMR (100 MHz, CDCl3) δ 179.1, 164.5, 162.2, 150.1, 134.6,
134.1, 132.8, 132.0, 131.1, 130.1, 129.8, 126.6, 125.7, 124.3, 123.7,
122.9. 118.3, 52.3 ppm; HRMS (EI+) m/z [M]+ Calcd for
C19H12N2O5 348.0746; found, 348.0741; mp 174−175 °C (dec).
3,5-Dimethoxyphenyl 3-Diazo-3,4-dihydro-4-oxo-2-naphthale-
necarboxylate (1n). Yellow solid; 97% yield (341 mg); IR (KBr)
2102, 1715, 1630, 1481, 1427, 1305, 1231, 1127, 1054 cm−1; 1H NMR
(400 MHz, CDCl3) δ 8.42 (dd, 1H, J = 7.8, 0.4 Hz), 7.72 (s, 1H),
7.76−7.71 (m, 2H), 7.65 (ddd, 1H, J = 8.2, 6.7, 1.7), 6.43−6.39 (m,
3H), 3.81 (s, 6H); 13CNMR (125 MHz, CDCl3) δ 179.1, 162.0, 161.3,
151.7, 134.5, 133.0, 131.1, 130.06, 130.05, 125.8, 124.1, 118.3, 100.0,
98.8, 55.6 ppm; HRMS (EI+) m/z [M]+ Calcd for C19H14N2O5
350.0903; found, 350.0906; mp 154−155 °C (dec).
Naphthalenyl 3-Diazo-3,4-dihydro-4-oxo-2-naphthalenecarbox-
ylate (1o). Orange solid; 47% yield (280 mg); IR (KBr) 2102, 1718,
1
1637, 1428, 1302, 1230 cm−1; H NMR (400 MHz, CDCl3) δ 8.46
(dd, 1H, J = 7.8, 0.6 Hz), 7.95 (s, 1H), 7.93 (ddd, 2H, J = 7.5, 2.6, 2.6
Hz), 7.84 (d, 1H, J = 8.3 Hz), 7.77 (d, 2H, J = 3.7 Hz), 7.70−7.66 (m,
1H), 7.57−7.52 (m, 3H), 7.39 (dd, 1H, J = 7.5, 0.9 Hz); 13CNMR
(100 MHz, CDCl3) δ 179.0, 162.3, 146.1, 134.7, 134.5, 133.3, 131.2,
130.14, 130.13, 128.2, 126.8, 126.7, 126.5, 125.8, 125.3, 124.2, 120.7,
G
DOI: 10.1021/acs.joc.5b01251
J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Note
118.2, 118.1, 76.8 ppm; HRMS (EI+) m/z [M]+ Calcd for
C21H12N2O3 340.0848; found, 340.0852; mp 183−184 °C (dec).
Phenyl 3-Diazo-3,4-dihydro-1methyl-4-oxo-2-naphthalenecar-
boxylate (1p). Orange solid; 93% yield (184 mg); IR (KBr) 2113,
1715, 1633, 1599, 1494, 1393, 1313, 1236, 1197, 1064 cm−1; 1H NMR
(500 MHz, CDCl3) δ 8.46 (dd, 1H, J = 7.9, 1.2 Hz), 7.96 (d, 1H, J =
8.1 Hz), 7.78 (ddd, 1H, J = 8.4, 7.3, 1.5 Hz), 7.64 (ddd, 1H, J = 8.0,
8.0, 0.9 Hz), 7.50−7.46 (m, 2H), 7.35−7.32 (ddd, 1H, J = 8.5, 8.4, 0.9
Hz), 7.24−7.22 (m, 2H), 2.78 (s, 3H); 13C NMR (125 MHz, CDCl3)
δ 178.9, 163.1, 150.0, 136.4, 133.0, 130.3, 129.8, 129.7, 129.2, 126.6,
126.2, 125.9, 121.3, 116.3, 16.4 ppm; HRMS (EI+) m/z [M]+ Calcd
for C18H12N2O3 304.0853; found, 304.0848; mp 135−136 °C (dec).
Phenyl 3-Diazo-3,4-dihydro-4-oxo-1-phenyl-2-naphthalenecar-
boxylate (1q). Orange solid; 85% yield (279 mg). IR (KBr) 3052,
2108, 1704, 1621, 1593, 1490, 1392, 1304, 1229, 1193 cm−1; 1H NMR
(500 MHz, CDCl3) δ 8.48 (dd, 1H, J = 6.7, 2.6 Hz), 7.61−7.56 (m,
2H), 7.51−7.44 (m, 3H), 7.37 (dd, 2H, J = 8.0, 1.4 Hz), 7.28−7.25
(m, 3H), 7.17 (t, 1H, J = 7.4 Hz), 6.66 (d, 2H, J = 7.7 Hz); 13CNMR
(125 MHz, CDCl3) δ 178.5, 163.1, 149.7, 137.6, 136.4, 133.8, 132.7,
130.4, 129.9, 129.3, 129.2, 129.0, 128.4, 128.0, 126.2, 125.6, 120.7,
117.6, 77.4 ppm; HRMS (EI+) m/z [M]+ Calcd for C23H14N2O3
366.1004; found, 366.1006; mp 163−164 °C (dec).
128.3, 128.2, 127.4, 123.6, 122.4, 119.9, 118.2, 116.5, 114.5, 21.0 ppm.
Anal. Found: C, 78.03; H, 4.41%. Calcd for C18H12O3: C, 78.25; H,
4.38%; mp 261−269 °C (dec).
12-Hydroxy-2-(sec-butyl)-6H-naphtho[2,3-c]chromen-6-one (2d).
Yellow solid; 73% yield (70.8 mg); IR (KBr) 3287, 2957, 2919, 2870,
1705, 1624, 1580, 1409, 1276, 1212 cm−1; 1H NMR (500 MHz,
DMSO-d6) δ 10.9 (brs, 1H), 9.21 (d, 1H, J = 1.7 Hz), 8.61 (s, 1H),
8.50 (d, 1H, J = 8.5 Hz), 8.21(d, 1H, J = 8.1 Hz), 7.76 (ddd, 1H, J =
8.4, 6.8, 1.2 Hz), 7.67 (ddd, 1H, J = 7.9, 0.8 Hz), 7.35−7.31 (m, 2H),
2.68−2.69 (m, 1H), 1.65 (q, 2H, J = 6.9 Hz), 1.29 (d, 3H, J = 6.9 Hz),
0.84 (t, 3H, J = 7.4 Hz); 13CNMR (125 MHz, DMSO-d6) δ 161.3,
151.5, 148.2, 143.4, 132.9, 130.1, 128.9, 128.8, 127.94, 127.92, 127.0,
124.1, 122.9, 120.4, 118.8, 117.1, 115.1, 41.4, 31.2, 22.5, 12.6 ppm.
Anal. Found: C, 79.20; H, 5.77%. Calcd for C21H18O3: C, 79.22; H,
5.70%; HRMS (EI+) m/z [M]+ Calcd for C21H18O3 318.1256; found,
318.1260; mp 231−232 °C (dec).
12-Hydroxy-2-methoxy-6H-naphtho[2,3-c]chromen-6-one (2e).
Pale beige solid; 67% yield (59.0 mg); IR (KBr) 3317, 1697, 1623,
1579, 1405, 1344, 1263, 1219 cm−1; 1H NMR (400 MHz, DMSO-d6)
δ 11.0 (brs, 1H), 8.89 (d, 1H, J = 3.0 Hz), 8.60 (s, 1H), 8.50 (d, 1H, J
= 8.4 Hz), 8.21 (d, 1H, J = 8.1 Hz), 7.76 (ddd, 1H, J = 8.1, 6.8, 1.1
Hz), 7.68 (ddd, 1H, J = 7.9, 7.2, 0.7 Hz), 7.34 (d, 1H, J = 8.9 Hz), 7.09
(dd, 1H, J = 8.9, 3.0 Hz), 3.86 (s, 3H); 13C NMR (125 MHz, DMSO-
d6) δ 160.8, 155.4, 151.2, 143.7, 132.5, 129.6, 128.5, 128.3, 127.5,
123.7, 122.5, 119.8, 119.0, 117.5, 114.8, 114.4, 112.5, 55.4 ppm;
HRMS (EI+) m/z [M]+ Calcd for C18H12O4 292.0736; found,
292.0741; mp 263−269 °C (dec).
2-Chloro-12-hydroxy-6H-naphtho[2,3-c]chromen-6-one (2f).
Gray solid; 60% yield (53.4 mg); IR (KBr) 3200, 1696, 1622, 1576,
1399, 1342, 1261, 1220, 1100 cm−1; 1H NMR (500 MHz, DMSO-d6)
δ 11.2 (brs, 1H), 9.32 (d, 1H, J = 2.8 Hz), 8.59 (s, 1H), 8.49 (d, 1H, J
= 8.5 Hz), 8.22(d, 1H, J = 8.2 Hz), 7.78 (ddd, 1H, J = 8.2, 6.7, 1.2 Hz),
7.70 (t, 1H, J = 7.1 Hz), 7.53 (dd, 1H, J = 8.6, 2.8 Hz), 7.42 (dd, 1H, J
= 8.6 Hz); 13CNMR (125 MHz, DMSO-d6) δ 160.2, 151.4, 148.2,
132.7, 129.6, 128.6, 128.3, 128.11, 128.09, 127.8, 127.2, 123.6, 122.5,
120.1, 119.5, 118.6, 113.1 ppm. Anal. Found: C, 68.82; H, 3.06%.
Calcd for C17H9ClO3: C, 68.53; H, 3.13%; HRMS (EI+) m/z [M]+
Calcd for C17H935ClO3 296.0240; found, 296.0242; mp 278−285 °C
(dec).
Phenyl 3-Diazo-3,4-dihydro-1-methoxy-4-oxo-2-naphthalene-
carboxylate (1r). Orange solid; 94% yield (301 mg); IR (KBr)
2942, 2100, 1710, 1628, 1573, 1484, 1400, 1300, 1226, 1186, 1014
1
cm−1; H NMR (500 MHz, CDCl3) δ 8.43 (dd, 1H, J = 8.0, 0.9 Hz),
8.04 (dd, 1H, J = 8.1, 0.6 Hz), 7.80 (ddd, 1H, J = 8.2, 7.3, 1.3 Hz), 7.69
(ddd, 1H, J = 8.2, 7.3, 1.2 Hz), 7.50−7.45 (m, 2H), 7.32 (ddd, 1H, J =
4.6, 4.6, 1.0 Hz), 7.27−7.25 (m, 2H), 4.06 (s, 3H); 13CNMR (125
MHz, CDCl3) δ 177.8, 161.6, 150.6, 150.2, 133.1, 132.7, 131.9, 130.3,
129.7, 126.5, 126.2, 124.6, 121.3, 108.0, 75.4, 63.7 ppm; HRMS (EI+)
m/z [M]+ Calcd for C18H12N2O4 320.0797; found, 320.0809; mp
131−132 °C (dec).
Typical Procedure for the Rh-Catalyzed Cyclization of Various 3-
Aryloxycarbonyldiazonaphthoquones 1. Reaction of Diazonaph-
thoquione 1b. To a solution of diazonaphthoquione 1b (88.3 mg,
0.304 mmol) in benzene (30 mL), Rh2(oct)4 (3.5 mg, 1.5 mol %) was
added at room temperature. The mixture was stirred for 1 h at 90 °C
as the bath temperature. After cooling the mixture, the precipitates
were collected by filtration to afford 2b (15.8 mg, 20% yield). The
filtrate were concentrated in vacuo to afford the crude compound,
which was purified by flash column chromatography (silica gel,
hexane/ethyl acetate = 6:1) to give 2b (42.9 mg, 54% yield).
12-Hydroxy-2-(tert-butyl)-6H-naphtho[2,3-c]chromen-6-one
(2a). Yellow solid; 92% yield (58.7 mg); IR (KBr) 3323, 2948, 1698,
1624, 1490, 1399, 1343, 1253, 1199 cm−1; 1H NMR (500 MHz,
CDCl3) δ 9.15 (d, 1H, J = 2.1 Hz), 8.74 (s, 1H), 8.07 (t, 2H, J = 9.2
Hz), 7.75 (t, 1H, J = 7.3 Hz), 7.63 (t, 1H, J = 7.0 Hz), 7.49 (dd 1H, J =
8.6, 2.1 Hz), 7.31 (d, 1H, J = 8.8 Hz), 6.29 (s, 1H), 4.06 (s, 9H);
13CNMR (125 MHz, CDCl3) δ 161.9, 148.3, 148.1, 147.4, 132.5,
130.4, 129.2, 127.3, 127.2, 126.5, 125.7, 124.9, 120.5, 119.2, 117.6,
116.9, 115.3, 34.8, 31.6 ppm; HRMS (EI+) m/z [M]+ Calcd for
C21H18O3 318.1256; found, 318.1252; mp 261−263 °C (dec).
12-Hydroxy-6H-naphtho[2,3-c]chromen-6-one (2b). Yellow solid;
74% yield (58.7 mg); IR (KBr) 3444, 1702, 1627, 1408, 1349, 1216,
753 cm−1; 1H NMR (400 MHz, DMSO-d6) δ 10.9 (brs, 1H), 9.32 (dd,
1H, J = 8.2, 1.6 Hz) 8.61 (s, 1H) 8.51 (d, 1H, J = 8.7 Hz) 8.20 (d, 1H,
J = 8.1 Hz) 7.77 (ddd, 1H, J = 8.4, 6.8, 1.2 Hz), 7.68 (ddd, 1H, J = 7.8,
6.9, 0.8 Hz), 7.50 (ddd, 1H, J = 8.4, 7.7, 1.6 Hz), 7.44−7.38 (m, 2H);
13CNMR (100 MHz, DMSO-d6) δ 161.2, 151.5, 149.9, 132.9, 130.1,
129.3, 128.9, 128.8, 128.7, 127.9, 124.9, 124.1, 123.0, 120.3, 119.1,
117.3, 114.9 ppm; HRMS (EI+) m/z [M]+ Calcd for C17H10O3
262.0630; found, 262.0621; mp 254−256 °C (dec).
12-Hydroxy-2-methyl-6H-naphtho[2,3-c]chromen-6-one (2c).
Yellow solid; 69% yield (57.1 mg); IR (KBr) 3231, 1697, 1624,
1583, 1402, 1349, 1263, 1219 cm−1; 1H NMR (500 MHz, DMSO-d6)
δ 10.8 (brs, 1H), 9.15 (s, 1H), 8.60 (s, 1H), 8.49 (d, 1H, J = 8.6 Hz),
8.21(d, 1H, J = 8.2 Hz), 7.76 (ddd, 1H, J = 8.3, 6.7, 1.2 Hz), 7.68 (t,
1H, J = 7.7), 7.32−7.27 (m, 2H), 2.44 (s, 3H); 13CNMR (125 MHz,
DMSO-d6) δ 160.8, 151.0, 147.5, 133.2, 132.4, 129.6, 129.4, 128.4,
12-Hydroxy-3-methyl-6H-naphtho[2,3-c]chromen-6-one (2g).
Yellow solid; 77% yield (67.7 mg); IR (KBr) 3405, 1708, 1623,
1
1400, 1266 cm−1; H NMR (400 MHz, DMSO-d6) δ 10.8 (brs, 1H),
9.16 (d, 1H, J = 8.1 Hz), 8.59 (s, 1H), 8.48 (d, 1H, J = 8.7 Hz), 8.19
(d, 1H, J = 8.1 Hz), 7.75 (ddd, 1H, J = 8.4, 6.8, 1.2 Hz), 7.66 (ddd, 1H,
J = 7.8, 0.8 Hz), 7.24 (d, 1H, J = 1.2 Hz), 7.21 (s, 1H), 3.34 (s, 3H);
13CNMR (125 MHz, DMSO-d6) δ 160.8, 150.5, 149.4, 139.0, 132.2,
129.6, 128.37, 128.35, 128.0, 127.2, 125.3, 123.6, 122.4, 119.7, 116.9,
115.8, 114.8, 20.6 ppm; HRMS (EI+) m/z [M]+ Calcd for C18H12O3
276.0786; found, 276.0787; mp 257−258 °C (dec).
12-Hydroxy-1-methyl-6H-naphtho[2,3-c]chromen-6-one (2′g).
Yellow solid; 8% yield (6.5 mg); IR (KBr) 3223, 1699, 1624, 1560,
1
1410, 1240, 1217, 1114 cm−1; H NMR (500 MHz, CDCl3) 8.56 (s,
1H), 8.40 (d, 1H, J = 8.5, 0.7 Hz), 8.04 (d, 1H, J = 8.1 Hz), 7.72 (ddd,
1H, J = 8.3, 6.8, 1.2 Hz), 7.66 (ddd, 1H, J = 8.1, 6.9, 1.2 Hz), 7.39
(ddd, 1H, J = 7.8 Hz), 7.26 (d, 1H, J = 7.1 Hz), 7.23 (d, 1H, J = 8.0
Hz), 5.59 (s, 1H), 2.55 (s, 3H); 13CNMR (125 MHz, CDCl3) δ 161.7,
150.8, 147.4, 135.0, 133.0, 129.3, 128.9, 128.7, 128.1, 127.8, 127.7,
124.4, 122.4, 121.7, 116.9, 114.7, 112.7, 22.2 ppm; HRMS (EI+) m/z
[M]+ Calcd for C18H12O3 276.0786; found, 276.0784; mp 215−217
°C (dec).
12-Hydroxy-3-methoxy-6H-naphtho[2,3-c]chromen-6-one (2h).
Yellow solid; 59% yield (51.5 mg); IR (KBr) 3385, 1699, 1616,
1508, 1287, 1254, 1137, 1031 cm−1; 1H NMR (400 MHz, DMSO-d6)
δ 10.7 (s, 1H), 9.22 (d, 1H, J = 9.0 Hz), 8.58 (s, 1H), 8.46 (d, 1H, J =
8.5 Hz), 8.18 (d, 1H, J = 8.1 Hz), 7.74 (ddd, 1H, J = 8.4, 6.8, 1.2 Hz),
7.64 (ddd, 1H, J = 7.7, 0.7 Hz), 7.02 (dd, 1H, J = 9.0, 2.7 Hz), 6.99 (d,
1H, J = 2.6 Hz), 3.87 (s, 3H); 13C NMR (125 MHz, DMSO-d6) δ
160.9, 159.5, 150.8, 149.7, 131.9, 129.6, 129.3, 128.44, 128.40, 126.9,
123.6, 122.2, 119.1, 115.1, 111.35, 111.29, 101.6, 55.5 ppm; HRMS
H
DOI: 10.1021/acs.joc.5b01251
J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Note
(EI+) m/z [M]+ Calcd for C18H12O4 292.0736; found, 292.0736; mp
279−280 °C (dec).
1H, J = 8.5, 0.7 Hz), 8.43 (d, 1H, J = 8.4 Hz), 7.79 (ddd, 1H, J = 8.4,
6.7, 1.2 Hz), 7.73 (ddd, 1H, J = 8.1, 6.7, 1.2 Hz), 7.46 (ddd, 1H, J =
8.7, 8.0, 1.5 Hz), 7.35 (ddd, 1H, J = 8.4, 7.2, 1.4 Hz), 7.33 (dd, 1H, J =
8.1, 1.3 Hz), 3.12 (s, 3H); 13C NMR (125 MHz, DMSO-d6) δ 160.8,
149.8, 149.2, 134.8, 133.2, 129.3, 129.1, 129.0, 128.7, 128.0, 126.5,
124.5, 123.4, 119.2, 118.4, 116.6, 116.0, 17.3 ppm; HRMS (EI+) m/z
[M]+ Calcd for C18H12O3 276.0796; found, 276.0786; mp 234−235
°C (dec).
12-Hydroxy-1-methoxy-6H-naphtho[2,3-c]chromen-6-one (2′h).
Pale yellow solid; 27% yield (23.8 mg); IR (KBr) 3158, 2949, 1717,
1562, 1468, 1392, 1301, 1244, 1197, 1080 cm−1; 1H NMR (400 MHz,
CDCl3) δ 10.0 (s, 1H), 8.64 (s, 1H), 8.56 (d, 1H, J = 8.3 Hz), 7.99 (d,
1H, J = 7.7 Hz), 7.70−7.62 (m, 2H), 7.45 (t, 1H, J = 8.2 Hz), 7.17 (dd,
1H, J = 8.1, 0.7 Hz), 7.03 (d, 1H, J = 8.2 Hz), 4.15 (s, 3H); 13C NMR
(125 MHz, CDCl3) δ 161.7, 153.6, 151.2, 150.5, 133.1, 129.4, 129.2,
128.7, 128.4, 128.0, 124.5, 124.2, 120.6, 113.0, 110.8, 109.9, 109.7, 58.6
ppm; HRMS (EI+) m/z [M]+ Calcd for C18H12O4 292.0736; found,
292.0735; mp 164−165 °C (dec).
12-Hydroxy-7-phenyl-6H-naphtho[2,3-c]chromen-6-one (2q).
Yellow solid; 87% yield (88.2 mg); IR (KBr) 3366, 1708, 1610,
1
1410, 1388, 1162 cm−1; H NMR (500 MHz, DMSO-d6) δ 10.9 (s,
1H), 9.36 (dd, 1H, J = 8.2, 1.4 Hz), 8.55 (d, 1H, J = 8.5 Hz), 7.75
(ddd, 1H, J = 8.3, 6.8, 1.0 Hz), 7.54 (ddd, 1H, J = 7.9, 6.8, 1.0 Hz),
7.49−7.37 (m, 5H), 7.33−7.31 (m, 2H), 7.22 (dd, 2H, J = 8.2, 1.5
Hz); 13C NMR (125 MHz, DMSO-d6) δ 159.4, 150.9, 149.9, 140.7,
137.9, 133.4, 129.5, 129.4, 129.0, 128.8, 128.71, 128.68, 128.3, 128.1,
124.5, 123.0, 119.1, 117.9, 116.8, 115.6 ppm; HRMS (EI+) m/z [M]+
Calcd for C23H14O3 338.0943; found, 338.0945; mp 281−284 °C
(dec).
12-Hydroxy-7-methoxy-6H-naphtho[2,3-c]chromen-6-one (2r).
Yellow solid; 86% yield (76.0 mg). IR (KBr) 3421, 1716, 1618,
1412, 1376, 1281, 1241, 1160, 1089 cm−1; 1H NMR (500 MHz,
DMSO-d6) δ 10.5 (s, 1H), 9.30 (dd, 1H, J = 8.2, 1.4 Hz), 8.47 (d, 1H,
J = 8.5 Hz), 8.33 (d, 1H, J = 8.3 Hz), 7.82 (ddd, 1H, J = 8.3, 6.8, 1.1
Hz), 7.34 (ddd, 1H, J = 7.8, 7.8, 0.7 Hz), 7.47 (ddd, 1H, J = 8.6, 8.2,
1.5 Hz), 7.36 (ddd, 1H, J = 8.4, 7.2, 1.3 Hz), 7.33 (dd, 1H, J = 8.0, 1.2
Hz), 3.97 (s, 3H); 13C NMR (125 MHz, DMSO-d6) δ 157.5, 154.6,
150.0, 147.0, 130.4, 129.6, 129.4, 128.9, 128.5, 128.0, 124.5, 124.2,
123.4, 119.0, 116.8, 115.6, 111.3, 63.2 ppm; HRMS (EI+) m/z [M]+
Calcd for C18H12O4 292.0736; found, 292.0744; mp 231−232 °C
(dec).
4-(tert-Butyl)phenyl 4-Hydroxy-3-phenyl-2-naphthalenecarboxy-
late (4). Beige solid; 46% yield (27.3 mg); IR (KBr) 3499, 2962, 1723,
1541, 1508, 1467, 1383, 1295, 1208, 1173, 1063 cm−1; 1H NMR (500
MHz, CDCl3) δ 8.30 (dd, 1H, J = 9.8, 1.4 Hz), 8.26 (s, 1H), 7.96 (dd,
1H, J = 8.9, 1.9 Hz), 7.66−7.53 (m, 4H), 7.49−7.43 (m, 3H), 7.30 (d,
2H, J = 8.7 Hz), 6.74 (d, 2H, J = 8.7 Hz), 5.68 (s, 1H), 1.27 (s, 9H);
13C NMR (125 MHz, CDCl3) δ 166.3, 149.0, 148.4, 148.2, 135.2,
132.7, 130.1, 129.4, 128.6, 128.4, 128.3, 127.8, 127.4, 126.1, 125.7,
123.7, 122.6, 120.6, 120.1, 34.4, 31.3 ppm; HRMS (EI+) m/z [M]+
Calcd for C27H24O3 396.1725; found, 396.1738.
3-Chloro-12-hydroxy-6H-naphtho[2,3-c]chromen-6-one (2i). Yel-
low solid; 74% yield (66.4 mg); IR (KBr) 3380, 1703, 1625, 1487,
1
1395, 1261, 1212 cm−1; H NMR (400 MHz, DMSO-d6) 11.0 (brs,
1H), 9.26 (d, 1H, J = 8.8 Hz), 8.56 (s, 1H) 8.49 (d, 1H, J = 8.6 Hz),
8.18 (d, 1H, J = 8.1 Hz), 7.75 (ddd, 1H, J = 8.4, 6.9, 1.2 Hz), 7.66 (t,
1H, J = 7.4 Hz), 7.48 (d, 1H, J = 2.3 Hz), 7.44 (dd, 1H, J = 8.8, 2.3
Hz); 13CNMR (100 MHz, DMSO-d6) δ 160.7, 151.6, 150.5, 133.0,
132.8, 130.1, 130.0, 129.0, 128.7, 128.1, 124.9, 124.2, 123.0, 119.9,
118.1, 117.2, 114.1 ppm; HRMS (EI+) m/z [M]+ Calcd for
C17H935ClO3 296.0242; found, 296.0238; mp 282−284 °C (dec).
12-Hydroxy-4-methyl-6H-naphtho[2,3-c]chromen-6-one (2j).
Yellow solid; 84% yield (69.7 mg); IR (KBr) 3336, 1698, 1624,
1
1407, 1346 cm−1; H NMR (500 MHz, DMSO-d6) δ 10.8 (brs, 1H),
9.19 (dd, 1H, J = 8.1, 0.8 Hz), 8.61 (s, 1H), 8.50 (d, 1H, J = 8.5 Hz),
8.20 (d, 1H, J = 8.1 Hz), 7.75 (ddd, 1H, J = 8.3, 6.8, 1.1 Hz), 7.67
(ddd, 1H, J = 7.8, 7.8, 0.8 Hz), 7.37 (dd, 1H, J = 7.2, 0.4 Hz), 7.29 (t,
1H, J = 7.6 Hz), 2.43 (s, 3H); 13C NMR (125 MHz, DMSO-d6) δ
161.2, 151.8, 148.1, 132.9, 130.6, 130.0, 129.0, 128.9, 127.9, 126.4,
125.7, 124.2, 123.8, 123.1, 120.3, 118.6, 115.3, 16.4 ppm; HRMS (EI+)
m/z [M]+ Calcd for C18H12O3 276.0786; found, 276.0788; mp 280−
285 °C (dec).
12-Hydroxy-4-methoxycarbonyl-6H-naphtho[2,3-c]chromen-6-
one (2k). Yellow solid; 44% yield (40.0 mg). IR (KBr) 3421, 1732,
1704, 1624, 1508, 1439, 1399, 1248 cm−1; 1H NMR (400 MHz,
DMSO-d6) δ 11.0 (brs, 1H), 9.52 (d, 1H, J = 7.7 Hz), 8.61 (s, 1H),
8.51 (d, 1H, J = 8.5 Hz), 8.22 (d, 1H, J = 8.1 Hz), 7.80−7.76 (m, 2H),
7.70 (t, 1H, J = 7.2 Hz), 7.48 (t, 1H, J = 7.9 Hz), 3.93 (s, 3H); 13C
NMR (100 MHz, DMSO-d6) δ 165.8, 160.4, 151.9, 147.8, 133.2,
132.0, 130.1, 129.8, 129.0, 128.9, 128.2, 124.3, 124.0, 123.1, 120.9,
120.0, 119.9, 114.3, 52.9 ppm; HRMS (EI+) m/z [M]+ Calcd for
C19H12O5 320.0685; found, 320.0682; mp 283−284 °C (dec).
12-Hydroxy-1,3-dimethoxy-6H-naphtho[2,3-c]chromen-6-one
(2n). Yellow solid; 90% yield (87.2 mg); IR (KBr) 3106, 1717, 1622,
1450, 1393, 1301, 1247 cm−1; 1H NMR (400 MHz, DMSO-d6) δ 9.87
(brs, 1H), 8.50 (s, 1H), 8.41 (d, 1H, J = 8.4 Hz), 8.14 (d, 1H, J = 8.2
Hz), 7.73−7.64 (m, 2H), 6.77 (d, 1H, J = 2.5 Hz), 6.76 (d, 1H, J = 2.5
Hz), 4.12 (s, 3H), 3.89 (s, 3H); 13C NMR (100 MHz, DMSO-d6) δ
161.3, 161.0, 155.6, 151.8, 149.1, 132.1, 129.3, 129.0, 128.9, 128.0,
123.7, 123.5, 120.4, 111.3, 101.6, 97.4, 96.3, 58.2, 56.4 ppm. Anal.
Found: C, 70.53; H, 4.37%. Calcd for C19H14O5: C, 70.80; H, 4.38%;
HRMS (EI+) m/z [M]+ Calcd for C19H14O5 322.0841; found,
322.0832; mp 230−231 °C (dec).
14-Hydroxy-8H-dinaphtho[2,3-c][1,2-e]pyran-8-one (2o). Gray
solid; 47% yield (41.0 mg); IR (KBr) 3449, 1701, 1624, 1498, 1330,
773 cm−1; 1H NMR (500 MHz, DMSO-d6) δ 10.9 (brs, 1H), 9.42 (d,
1H, J = 7.3 Hz), 8.67 (s, 1H), 8.51 (d, 1H, J = 6.8 Hz), 8.40 (d, 1H, J =
6.5 Hz), 8.22 (d, 1H, J = 6.5 Hz), 7.99 (d, 1H, J = 6.1 Hz), 7.89 (d,
1H, J = 7.3 Hz), 7.77 (t, 1H, J = 5.9 Hz), 7.69−7.62 (m, 3H); 13C
NMR (125 MHz, DMSO-d6) δ 161.1, 151.6, 144.9, 133.2, 133.0,
130.1, 129.1, 128.9, 127.9, 127.8, 127.7, 127.3, 125.4, 124.2, 123.9,
123.4, 123.0, 121.7, 120.3, 115.6, 114.6 ppm. Anal. Found: C, 70.53;
H, 4.37%. Calcd for C19H14O5: C, 70.80; H, 4.38%; HRMS (EI+) m/z
[M]+ Calcd for C21H12O3 312.0786; found, 312.0793; mp >300 °C
(dec).
2-Methoxycarbonyl-4-(methoxymethoxy)methyl-3-methylphenyl
7-Chloro-4-hydroxy-5,8-dimethoxy-2-naphthoate (7). To a solution
of phenol 67a (1.76 g, 7.35 mmol), carboxylic acid 57a (1.00 g, 3.54
mmol) in dichloromethane (35 mL), 1-ethyl-3-(3-(dimethylamino)-
propyl)carbodiimide (EDCI) (0.742 g, 3.87 mmol), and N,N-
dimethyl-4-aminopyridine (DMAP) (0.423 g, 3.46 mmol) were
added at room temperature, and the mixture was stirred for 1.5 h.
The reaction was quenched with water, and organic materials were
extracted three times with ethyl acetate. The combined extracts were
washed with water and brine and then dried over anhydrous sodium
sulfate. The solvent was removed in vacuo to afford crude compounds.
The crude materials were purified by flash column chromatography
(silica gel: hexane/ethyl acetate = 6/1) to give ester 7 (0.909 g, 51%
yield) as a white solid. IR (KBr) 3477, 3073, 2960, 1685, 1508, 1451,
1
1410, 1348, 1315, 1207, 1005 cm−1; H NMR (500 MHz, CDCl3) δ
9.27 (s, 1H), 8.41 (d, 1H, J = 1.6 Hz), 7.56 (d, 1H, J = 1.6 Hz), 7.19
(s, 1H), 7.16 (s, 1H), 6.86 (s, 1H), 4.72 (s, 2H), 4.62 (s, 2H), 4.07 (s,
3H), 3.99 (s, 3H), 3.74 (s, 3H), 3.41 (s, 3H), 2.45 (s, 3H); 13C NMR
(125 MHz, CDCl3) δ 166.7, 164.5, 155.3, 152.3, 148.9, 147.3, 141.4,
138.7, 130.7, 129.2, 127.0, 125.1, 123.5, 119.3, 116.9, 116.3, 110.9,
108.0, 95.8, 68.0, 61.5, 56.7, 55.4, 52.1, 20.1 ppm; HRMS (EI+) m/z
[M]+ Calcd for C25H2535ClO9 504.1187; found, 504.1180; mp 107−
108 °C (dec).
Methyl 3-(6-Chloro-1-hydroxy-3-hydroxymethyl-5,8-dimethox-
yaphthalen-2-yl)-2-hydroxy-4-(methoxymethoxy)methyl-6-methyl-
benzoate (10).7a To a solution of 2-chloro-1,3-dimethylimidazolinium
chloride (152.0 mg, 0.899 mmol) in acetonitrile (1 mL), sodium azide
(228.6 mg, 3.52 mmol) and 15-crown-5 (12.2 mg, 0.0554 mmol) were
added at −30 °C, and the mixture was stirred for 1 h. Ester 7 (101.0
12-Hydroxy-7-methyl-6H-naphtho[2,3-c]chromen-6-one (2p).
Yellow solid; 81% yield (67.7 mg); IR (KBr) 3369, 1702, 1616,
1407, 1380, 1277, 1242, 1222, 1108 cm−1; 1H NMR (500 MHz,
DMSO-d6) δ 10.5 (brs, 1H), 9.29 (dd, 1H, J = 8.2, 1.4 Hz), 8.49 (dd,
I
DOI: 10.1021/acs.joc.5b01251
J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Note
mg, 0.200 mmol) and triethylamine (36.3 mg, 0.0358 mmol) in THF
(2 mL) were added to the mixture, which was stirred for 6 h. The
reaction was quenched with buffer (pH 7), and organic materials were
extracted four times with ethyl acetate. The combined extracts were
washed with water and brine, and then dried over anhydrous sodium
sulfate. The solvent was removed in vacuo to afford crude compounds.
Rh2(oct)4 (3.5 mg, 1.5 mol %) was added to a solution of the crude
material in benzene (20 mL) at room temperature. The mixture was
stirred for 2.5 h at 90 °C as the bath temperature. After cooling the
mixture, the solvent was concentrated in vacuo. The residue was
diluted with THF/MeOH (20:1) (6.3 mL). To the mixture, NaBH4
(30.6 mg, 0.0809 mmol) was added at −45 °C. After stirring the
mixture for 4 h, the reaction was stopped by adding two drops of
AcOH at that temperature. After warming the mixture to room
temperature, water was added, and the mixture was extracted three
times with ethyl acetate. The combined extracts were washed with
water and brine, and then dried over anhydrous sodium sulfate. The
solvent was removed in vacuo to afford crude compounds. The crude
materials were purified by flash column chromatography (silica gel:
hexane/ethyl acetate = 7/3) to give triol 10 (56.0 mg, 55% yield) as a
yellow solid. IR (KBr) 3384, 2936, 1734, 1655, 1597, 1451, 1362,
(b) Ueberschaar, N.; Xu, Z.; Scherlach, K.; Metsa-Ketela, M.;
̈
̈
Bretschneider, T.; Dahse, H.-M.; Gorls, H.; Hertweck, C. J. Am.
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Chem. Soc. 2013, 135, 17408. (c) Hatano, K.; Higashide, E.; Shibata,
M.; Kameda, Y.; Horii, S.; Mizuno, K. Agric. Biol. Chem. 1980, 44,
1157. (d) Horii, S.; Fukase, H.; Mizuta, E.; Hatano, K.; Mizuno, K.
Chem. Pharm. Bull. 1980, 28, 3601.
(5) (a) Bringmann, G.; Menche, D. Angew. Chem., Int. Ed. 2001, 40,
1687. (b) Bringmann, G.; Saeb, W.; Rubenacker, M. Tetrahedron 1999,
̈
55, 423.
(6) (a) Hauser, F. M.; Combs, D. W. J. Org. Chem. 1980, 45, 4071.
(b) Matsumoto, T.; Hosoya, T.; Suzuki, K. J. Am. Chem. Soc. 1992,
114, 3568. (c) Hosoya, T.; Takashiro, E.; Matsumoto, T.; Suzuki, K. J.
Am. Chem. Soc. 1994, 116, 1004. (d) Garino, C.; Bihel, F.;
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Pietrancosta, N.; Laras, Y.; Quelever, G.; Woo, I.; Klein, P.; Bain, J.;
Boucher, J.-L.; Kraus, J.-L. Bioorg. Med. Chem. Lett. 2005, 15, 135.
(e) Sun, W.; Cama, L. D.; Birzin, E. T.; Warrier, S.; Locco, L.; Mosley,
R.; Hammond, M. L.; Rohrer, S. P. Bioorg. Med. Chem. Lett. 2006, 16,
1468. (f) Hager, A.; Mazunin, D.; Mayer, P.; Trauner, D. Org. Lett.
2011, 13, 1386.
(7) (a) Kitamura, M.; Ohmori, K.; Kawase, T.; Suzuki, K. Angew.
Chem., Int. Ed. 1999, 38, 1229. (b) Ohmori, K.; Tamiya, M.; Kitamura,
M.; Kato, H.; Oorui, M.; Suzuki, K. Angew. Chem., Int. Ed. 2005, 44,
3871. (c) Tamiya, M.; Ohmori, K.; Kitamura, M.; Kato, H.; Arai, T.;
Oorui, M.; Suzuki, K. Chem. - Eur. J. 2007, 13, 9791.
(8) (a) Koch, K.; Podlech, J.; Pfeiffer, E.; Metzler, M. J. Org. Chem.
2005, 70, 3275. (b) Alam, A.; Tsuboi, S. Tetrahedron 2007, 63, 10454.
(c) Tatsuta, K.; Furuyama, A.; Yano, T.; Suzuki, Y.; Ogura, T.;
Hosokawa, S. Tetrahedron Lett. 2008, 49, 4036. (d) Thasana, N.;
Worayuthakarn, R.; Kradanrat, P.; Hohn, E.; Young, L.; Ruchirawat, S.
J. Org. Chem. 2007, 72, 9379. (e) Li, Y.; Ding, Y.-J.; Wang, J.-Y.; Su, Y.-
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Q. J.; Worm, K.; Dolle, R. E. J. Org. Chem. 2004, 69, 5147. (c) Abe, H.;
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Tetrahedron Lett. 2005, 46, 3197. (d) Kemperman, G. J.; Ter Horst, B.;
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1
1258, 1202, 1106, 1041, 1014, 973, 945 cm−1; H NMR (500 MHz,
CDCl3) δ 11.76 (s, 1H), 9.45 (s, 1H), 7.80 (s, 1H), 7.03 (s, 1H), 6.73
(s, 1H), 4.53 (d, 1H, J = 6.6 Hz), 4.46 (d, 2H, J = 5.7 Hz), 4.42 (d, 1H,
J = 6.6 Hz), 4.33 (d, 1H, J = 12.3 Hz), 4.27 (d, 1H, J = 12.3 Hz), 3.99
(s, 3H), 3.98 (s, 3H), 3.97 (s, 3H), 3.13 (s, 3H), 2.74 (t, 1H, J = 6.0
Hz), 2.63 (s, 3H); 13C NMR (125 MHz, CDCl3) δ 172.3, 159.9, 152.5,
151.2, 146.5, 143.6, 141.3, 141.2, 131.0, 123.1, 122.7, 121.2, 117.1,
113.9, 113.0, 111.9, 105.8, 96.1, 67.3, 64.0, 61.2, 56.5, 55.2, 52.3, 24.2
ppm.
ASSOCIATED CONTENT
* Supporting Information
■
S
NMR spectra of 1, 2, 2′, 3, 4, 7, and 10. The Supporting
Information is available free of charge on the ACS Publications
website at DOI: 10.1021/acs.joc.5b01251.
AUTHOR INFORMATION
Corresponding Author
*E-mail: kita@che.kyutech.ac.jp.
■
Notes
(10) (a) Kitamura, M.; Tashiro, N.; Sakata, R.; Okauchi, T. Synlett
2010, 2010, 2503. (b) Kitamura, M.; Sakata, R.; Tashiro, N.; Ikegami,
A.; Okauchi, T. Bull. Chem. Soc. Jpn. 2015, 88, 824.
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
This work was supported by JSPS KAKENHI Grant Number
26410054.
■
(11) Reaction of 2-azido-1,3-dimethylimidazolinium salts. For a
review see: (a) Kitamura, M. Yuki Gosei Kagaku Kyokaishi 2014, 72,
14. Related publications, see: (b) Kitamura, M.; Tashiro, N.;
Takamoto, Y.; Okauchi, T. Chem. Lett. 2010, 39, 732. (c) Kitamura,
M.; Yano, M.; Tashiro, N.; Miyagawa, S.; Sando, M.; Okauchi, T. Eur.
J. Org. Chem. 2011, 2011, 458. (d) Kitamura, M.; Koga, T.; Yano, M.;
Okauchi, T. Synlett 2012, 23, 1335. (e) Kitamura, M.; Murakami, K.;
Shiratake, Y.; Okauchi, T. Chem. Lett. 2013, 42, 691. (f) Kitamura, M.;
Kato, S.; Yano, M.; Tashiro, N.; Shiratake, Y.; Sando, M.; Okauchi, T.
Org. Biomol. Chem. 2014, 12, 4397.
(12) For a recent study on the metal-catalyzed reaction of
diazonaphthoquinones, see: (a) Kitamura, M.; Sakata, R.; Okauchi,
T. Tetrahedron Lett. 2011, 52, 1931. (b) Kitamura, M.; Kisanuki, M.;
Sakata, R.; Okauchi, T. Chem. Lett. 2011, 40, 1129. (c) Kitamura, M.;
Kisanuki, M.; Okauchi, T. Eur. J. Org. Chem. 2012, 2012, 905.
(d) Kitamura, M.; Araki, K.; Matsuzaki, H.; Okauchi, T. Eur. J. Org.
Chem. 2013, 2013, 5045. (e) Kitamura, M.; Kisanuki, M.; Kanemura,
K.; Okauchi, T. Org. Lett. 2014, 16, 1554.
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