Rh(II)-Catalyzed Synthetic Strategy for Diverse and Functionalized Halonaphthalenyl Ethers and Esters from Diazo Compounds and Its Application to Polyaromatic Compounds

Article abstract of DOI:10.1055/s-0035-1561295

An efficient and simple synthesis of various functionalized halonaphthalenyl ethers and esters in moderate to good yield was achieved via rhodium(II)-catalyzed reaction of readily available diazo compounds with benzyl halides or acid halides. This methodology has several advantages, such as ease of handling, mild reaction conditions, bromine- or chlorine-free route, and the use of an effective catalyst. The synthesized compounds were further converted into valuable polyaromatic compounds using the Suzuki reaction.

Full text of DOI:10.1055/s-0035-1561295

SYNTHESIS
0
0
3
9
-
7
8
8
1
1
4
3
7
-
2
1
0
X
© Georg Thieme Verlag Stuttgart · New York
2016, 48, 579–587
paper
579
E. R. Baral et al.
Paper
Synthesis
Rh(II)-Catalyzed Synthetic Strategy for Diverse and Functionalized
Halonaphthalenyl Ethers and Esters from Diazo Compounds and
Its Application to Polyaromatic Compounds
Ek Raj Barala
R4
R4
R5
Yong Rok Lee*a
Sung Hong Kimb
Young-Jung Weec
X
N2
X
R3
O
R3
O
R5
Rh (II)
(2 mol%)
R1
R2
B(OH)2
R1
R2
O
a School of Chemical Engineering, Yeungnam University,
Gyeongsan 712-749, Republic of Korea
Pd(PPh3)4
K2CO3
Rh (II)
(2 mol%)
R6
X
R6
R7
R7
R4
yrlee@yu.ac.kr
R6
b Analysis Research Division, Daegu Center, Korea Basic Science
Institute, Daegu 702-701, Republic of Korea
c Department of Food Science and Technology, Yeungnam
University, Gyeongsan 712-749, Republic of Korea
R5
X
R3
O
O
R3
O
R6
R1
R2
R1
R2
Received: 04.11.2015
Accepted: 23.11.2015
Published online: 28.12.2015
DOI: 10.1055/s-0035-1561295; Art ID: ss-2015-f0644-op
photolytic reaction,9 palladium- or copper-catalyzed reac-
tions,10,11 and Cu-Mn spinel oxide catalyzed reaction,12 and
further reactions using a non-heme iron halide complex13
and iron(III) meso-chloro-isoporphyrin.14
Abstract An efficient and simple synthesis of various functionalized
halonaphthalenyl ethers and esters in moderate to good yield was
achieved via rhodium(II)-catalyzed reaction of readily available diazo
compounds with benzyl halides or acid halides. This methodology has
several advantages, such as ease of handling, mild reaction conditions,
bromine- or chlorine-free route, and the use of an effective catalyst.
The synthesized compounds were further converted into valuable pol-
yaromatic compounds using the Suzuki reaction.
Despite their merits, many of the reported methods suf-
fer from drawbacks, including toxic reagents, harsh reaction
conditions, side reactions of overhalogenation, low yields,
and low chemo- and regioselectivity. Therefore, more envi-
ronmentally benign and efficient methods are needed to
overcome these limitations, which prompted this study to
develop new approaches for the halogenation of aromatic
compounds via the decomposition of diazo compounds.
The decomposition of diazo compounds has been used
widely in organic synthesis, and it is an important tool for
the synthesis of a wide range of organic molecules.15 Previ-
ous studies examined the decomposition of diazo com-
pounds and various substrates, developing novel methodol-
ogies for the synthesis of heterocycles16 and valuable mole-
cules.17 Among these, a methodology for preparing β-
substituted α-haloenones and α,β-dihaloenones using rho-
dium(II)- or ruthenium(II)-catalyzed reactions of cyclic di-
azodicarbonyl compounds with acid chlorides, benzyl ha-
lides, or oxalyl halides was reported.18,19 In related work, the
transition-metal-catalyzed20 and hypervalent iodine-based
halogenations of diazo compounds have been reported by
other groups.21
Key words diazo compounds, rhodium(II) catalyst, halonaphthalenyl
ethers, halonaphthalenyl esters, polyaromatic compounds
The halogenation of aromatic compounds provides im-
portant chemical precursors for the synthesis of valuable
drugs, pharmaceuticals, agrochemicals, bioactive natural
products, and photographic materials.1 In addition, haloge-
nated aromatic compounds have been widely used as key
intermediates in the preparation of organometallic reagents
for the synthesis of a wide variety of biologically active
molecules and functional materials.2 They have also found
widespread utility as vital starting materials in transition-
metal-catalyzed coupling reactions for the preparation of
new molecules.3 Typical approaches for the halogenation of
aromatic molecules include direct electrophilic aromatic
substitution using Cl2 and Br2 in the presence of Lewis
acids, Brønsted acids, and ionic liquids as catalysts and pro-
moters.4 These methods are quite cumbersome because of
their toxicity and hazardous nature. To avoid these prob-
lems, other methods using N-halosuccinimide/catalysts,5
HX/peroxides,6 MX/peroxides,7 and MX/hypervalent io-
dines8 as halogenating reagents have been developed. In ad-
dition, a variety of other effective approaches for halogena-
tion have also been reported, which include iron-mediated
As a result of an ongoing study in this area, herein we
report rhodium(II)-catalyzed reactions of 1-diazonaphtha-
len-2(1H)-ones with benzyl halides to form diverse and
functionalized halonaphthalenyl ethers. This is the first ex-
ample of the synthesis of diverse and functionalized ha-
lonaphthalenyl ethers starting from diazo compounds 1a–e
and benzyl halides 2a–e by rhodium(II)-catalyzed reactions
(Scheme 1).
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2016, 48, 579–587

580
E. R. Baral et al.
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Synthesis
R4
R4
R5
R5
X
X
N2
R3
O
R3
O
2
Rh(II)
(2 mol%)
R1
R1
R2
R2
3
1
created bonds
1a R1 = R2 = R3 = H
2a X = Br, R4 = R5 = H
2b X = Br, R4 = Me, R5 = H
2c X = Br, R4 = H, R5 = Me
2d X = Br, R4 = H, R5 = Cl
2e X = Cl, R4 = R5 = H
1b R1 = H, R2 = OMe, R3 = H
1c R1 = H, R2 = H, R3 = OMe
1d R1 = H, R2 = Br, R3 = H
1e R1 = OMe, R2 = R3 = H
Scheme 1 Rhodium(II)-catalyzed synthesis of various halonaphthalenyl ethers from 1-diazonaphthalen-2(1H)-ones
The diazo compounds 1a–e and 6 were prepared from
the corresponding naphthols using 2-azido-1,3-dimeth-
ylimidazolinium chloride according to the reported proce-
dure.22 This study commenced by optimizing the reaction
conditions for the synthesis of 3a using various catalysts
and solvents (Table 1).
room temperature for 24 hours (entries 1–5). With 2 mol%
of tris(triphenylphosphine)ruthenium(II) dichloride in flu-
orobenzene at room temperature for 24 hours, product 3a
was obtained in 10% yield (entry 6). With 2 mol% of rhodi-
um(II) acetate at room temperature for 24 hours, the yield
of product 3a increased to 35% (entry 7). The best yield
(70%) was obtained with 2 mol% of rhodium(II) pivalate in
fluorobenzene at room temperature for 15 hours (entry 8).
The yield of 3a did not increase using other solvents, such
as benzene, toluene, and dichloromethane (entries 9–11).
Increasing or decreasing the rhodium(II) pivalate loading
did not improve the yield (entries 12 and 13). The structure
of 3a was determined by analysis of the spectral data and
by comparison with the spectra of a reported compound.23
The 1H NMR spectrum of 3a showed a benzylic signal at δ =
5.20 as a singlet. The structure was further confirmed by
the 13C NMR spectrum, which showed the benzylic carbon
at δ = 71.8.
Under the optimized conditions, the generality of this
decomposition reaction was explored further by employing
different diazo compounds and benzyl halides (Figure 1).
Reactions of 1a with 3-methyl- or 4-methylbenzyl bromide
bearing electron-donating group in fluorobenzene afforded
the expected products 3b and 3c in 65 and 62% yield, re-
spectively. In addition, the reactions of diazo compound
1b–d bearing electron-donating or -withdrawing groups,
such as OMe or Br, on the benzene ring were also successful.
The reaction of 1b or 1c bearing an electron-donating group
with 2a–c provided the desired products 3d–h in 60–70%
yield, and that of 1d bearing an electron-withdrawing
group afforded 3i–k in 55–72% yield. Similarly, the diazo 1d
yielded the product 3l in 60% when treated with 4-chloro-
benzyl bromide bearing electron-withdrawing group in the
para position. The combination of the other diazo com-
pound 1e with benzyl or 3-methylbenzyl bromide afforded
3m (69%) and 3n (63%), respectively. The combination of di-
azo compounds 1d or 1e with benzyl chloride provided the
corresponding products 3o and 3p in 57 and 60% yield, re-
spectively.
Table 1 Optimization for the Synthesis of 3a from 1a and 2a Using
Various Catalysts and Solventsa
Br
Br
N2
O
O
2a
catalyst
solvent
3a
1a
Entry Catalyst
Solvent
Conditions
Yieldb (%)
1
In(OAc)3 (5 mol%)
PhF
r.t., 24 h
r.t., 24 h
r.t., 24 h
r.t., 24 h
r.t., 24 h
r.t., 24 h
r.t., 24 h
r.t., 15 h
r.t., 15 h
r.t., 15 h
r.t., 15 h
r.t., 15 h
r.t., 15 h
0
2
Cu(OAc)2 (5 mol%)
FeCl3 (5 mol%)
PhF
0
3
PhF
0
4
Au(PPh3)3Me (5 mol%)
Pd(OAc)2 (5 mol%)
Ru(PPh3)3Cl2 (2 mol%)
Rh2(OAc)4 (2 mol%)
Rh2(OPiv)4 (2 mol%)
Rh2(OPiv)4 (2 mol%)
Rh2(OPiv)4 (2 mol%)
Rh2(OPiv)4 (2 mol%)
Rh2(OPiv)4 (1 mol%)
Rh2(OPiv)4 (5 mol%)
PhF
0
5
PhF
0
6
PhF
10
35
70
60
65
40
48
52
7
PhF
8
PhF
9
benzene
toluene
CH2Cl2
PhF
10
11
12
13
PhF
a Reactions were carried out using 1a (1.0 mmol) and 2a (10 mmol) in sol-
vent (5 mL) under N2.
b Isolated yield after column chromatography.
No products were formed when 1a was treated with 2a
in the presence of 5 mol% of indium(III) acetate, copper(II)
acetate, iron(III) chloride, methyltris(triphenylphos-
phine)gold(I), and palladium(II) acetate in fluorobenzene at
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Br
Br
Br
O
O
O
MeO
3d, 17 h (64%)
3c, 17 h (62%)
3b, 17 h (65%)
Br
Br
Br
O
O
MeO
O
MeO
MeO
3e, 18 h (60%)
3f, 18 h (62%)
3g, 17 h (70%)
Br
Br
Br
O
O
MeO
O
Br
Br
3j, 18 h (59%)
3h, 18 h (60%)
3i, 15 h (72%)
Cl
Br
Br
Br
O
O
O
OMe
Br
Br
3k, 18 h (55%)
3l, 17 h (60%)
3m, 15 h (69%)
Cl
Cl
Br
O
O
O
OMe
3p, 18 h (60%)
Br
OMe
3n, 15 h (63%)
3o, 18 h (57%)
Figure 1 Formation of various halonaphthalenyl ethers 3b–p from the 1-diazonaphthalene-2(1H)-ones 1a–e and benzyl halides 2a–e
To further demonstrate the versatility of this reaction,
other decomposition reactions using acid halides, which
will lead to the formation of halonaphthalenyl esters, were
next examined (Scheme 2). For example, the decomposition
of 1a–d with acetyl chloride (4a) in fluorobenzene at room
temperature for 17 hours provided the corresponding
chloronaphthalenyl chlorides 5a–d in 52–60% yield. Simi-
larly, the reaction of 1b with benzoyl bromide (4b) in fluo-
robenzene afforded bromonaphthalenyl ester 5e in 52%
yield after 17 hours.
Considering the general applicability for the synthesis
of 1-halonaphthalenyl ethers 3a–p and 1-halonaphthalenyl
esters 5a–e using 1-diazonaphthalen-2(1H)-ones 1a–e as
the starting materials, this study examined whether this
approach was suitable using 2-diazonaphthalen-1(2H)-one
(6), which will allow the formation of the 2-halonaphthale-
nyl ether and 2-halonaphthalenyl ester (Scheme 3). Reac-
tion of 6 with 2a in the presence of 2 mol% of rhodium(II)
pivalate in fluorobenzene at room temperature for 18 hours
O
X
N2
R3
X
R2
O
O
R2
O
4
R3
Rh2(OPiv)4 (2 mol%)
PhF, N2, r.t.
R1
R1
5
1
5a R1 = R2 = H, R3 = Me, X = Cl, 52%
4a R3 = Me, X = Cl
4b R3 = Ph, X = Br
1a R1 = R2 = H
1b R1 = OMe, R2 = H
5b R1 = OMe, R2 = H, R3 = Me, X = Cl, 56%
5c R1 = H, R2 = OMe, R3 = Me, X = Cl, 58%
5d R1 = Br, R2 = H, R3 = Me, X = Cl, 60%
5e R1 = OMe, R2 = H, R3 = Ph, X = Br, 52%
1c R1 = H, R2 = OMe
1d R1 = Br, R2 = H
Scheme 2 Reaction of diazo compounds 1a–d with acetyl chloride (4a) or benzoyl bromide (4b) for the formation of chloro or bromonaphthalenyl
esters 5a–e
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O
O
Br
O
Cl
O
N2
2a
4a
O
Cl
Rh2(OPiv)4
(2 mol%)
PhF
Rh2(OPiv)4
(2 mol%)
PhF
Br
6
18 h
18 h
8 (52%)
7 (55%)
Scheme 3 Reaction of 2-diazonaphthalen-1(2H)-one (6) with 2a and 4a for the synthesis of bromonaphthalenyl ether 7 and chloronaphthalenyl ester
8
provided 2-bromonaphthalenyl ether 7 (55%), and the reac-
tion with acetyl chloride (4a) afforded 2-chloronaphthale-
nyl ester 8 (52%).
(12a), 3-methoxyphenyl- (12b) or 3,5-dimethoxyphenylbo-
ronic acid (12c) in the presence of 5 mol% of Pd(PPh3)4 in
refluxing aqueous toluene for 16–20 hours gave 13a–c in
70, 72, and 77% yield, respectively, whereas the treatment
of 3e bearing a methoxy group on the naphthalenyl ring
with 12a or 12b formed 13d and 13e in 71 and 78% yield,
respectively. Importantly, the reaction of 3i bearing a Br
group on the naphthalenyl ring with 2.2 equivalents of 12a
in refluxing aqueous toluene for 16 hours provided product
13f in 73% yield. The formation of these products was con-
The proposed reaction mechanism for the formation of
3a and 5a can be explained, as shown in Scheme 4. The di-
azo compound 1a in the presence of rhodium(II) catalyst
first formed rhodium carbenoid 9 by loss of nitrogen. The
nucleophilic attack of the bromine atom of benzyl bromide
to 9 provided another intermediate 10. The intramolecular
nucleophilic attack of oxygen to carbon on the benzylic po-
sition followed by C–Br bond cleavage provided the final
product 3a. In the case of ester formation of 5a, nucleophil-
ic attack of the chlorine atom of the acid chloride to rhodi-
um carbenoid 9 provided intermediate 11, which under-
went intramolecular nucleophilic attack followed by cleav-
age of the C–Cl bond to produce the product 5a.
As an application of this methodology, the conversion of
the synthesized compounds 3a, 3e, and 3i into polyaromat-
ic compounds was next attempted using the Suzuki reac-
tions, as shown in Scheme 5. Recently, naphthalenyl group
based polyaromatic molecules have attracted considerable
interest in the fields of light emitting diodes (LEDs) and or-
ganic light emitting diodes (OLEDs) because they are used
widely as highly efficient and stable-light emitting materi-
als.24 The reaction of 3a with 1.1 equivalents of phenyl-
1
firmed by H and 13C NMR spectroscopy. The results show
that this synthetic approach can be used widely to intro-
duce benzene rings on the naphthalenyl nucleus.
An environmentally benign and efficient process for the
synthesis of diverse halonaphthalenyl ethers and esters was
developed by the rhodium(II)-catalyzed reaction of diazo
compounds and benzyl halides or acid halides. This syn-
thetic approach for various functionalized halonaphthale-
nyl ethers and esters involves simultaneous halogenation
and ether or ester formation as a one-pot procedure. This
novel protocol has important advantages, such as simple
operation, bromine- or chlorine-free route, and mild cata-
lyst, over the existing methodologies. The synthesized com-
pounds were further transformed into valuable polyaro-
matic compounds using the Suzuki reaction.
Br
N2
RhLn
Br
–
+
O
O
LnRh Br
O
RhLn
2a
O
– RhLn
1a
O
9
10
3a
Cl
Cl
O
–
+
LnRh Cl
O
O
O
– RhLn
11
Scheme 4 Proposed mechanism for the formation of 3a and 5a
5a
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Synthesis
R2
R3
R4
O
Br
B(OH)2
R2
O
Pd(PPh3)4
(5 mol%)
+
R1
3a R1 = R2 = H
3e R1 = OMe, R2 = Me
3i R1 = Br, R2 = H
K2CO3
toluene/H2O
reflux
R4
R3
12a R3 = R4 = H
12b R3 = OMe, R4 = H
12c R3 = R4 = OMe
R1
13a–f
MeO
MeO
OMe
O
O
O
13a, 20 h (70%)
13b, 18 h (72%)
MeO
13c, 16 h (77%)
O
O
O
MeO
13d, 16 h (71%)
MeO
13f, 16 h (73%)
13e, 16 h (78%)
Scheme 5 Formation of polyaromatic compounds 13a–f by the Suzuki coupling reaction of the synthesized compounds 3a, 3e, and 3i
All experiments were carried out under a N2 atmosphere. Merck, pre-
coated silica gel plates (Art. 5554) with a fluorescent indicator were
used for analytical TLC. Flash column chromatography was performed
using silica gel 9385 (Merck). 1H NMR spectra were recorded on
Varian VNS 300 or 600 MHz or DPX (Bruker) 300 MHz spectrometers
relative to TMS (δ = 0) as internal standard or relative to the resonance
of the residual protonated solvent (1H: CDCl3, δ = 7.24). 13C NMR spec-
tra were obtained at 75 MHz or 150 MHz spectrometers and refer-
enced to the internal solvent signals (13C: CDCl3, δ = 77.0). IR spectra
were recorded on a Jasco FTIR 5300 spectrophotometer. Melting
points were measured with a Fisher-Johns melting point apparatus
and are uncorrected. HRMS were measured using a Jeol JMS-600
mass spectrometer (positive ion EI mode) at the Korean Basic Science
Institute.
13C NMR (75 MHz, CDCl3): δ = 153.0, 136.6, 130.0, 129.2, 128.7, 128.5,
127.9, 127.7, 127.6, 127.1, 126.2, 124.4, 115.6, 110.0, 71.8.
HRMS (EI): m/z [M+] calcd for C17H13BrO: 312.0150; found: 312.0150.
1-Bromo-2-(3-methylbenzyloxy)naphthalene (3b)
Solid; yield: 212 mg (65%); mp 46–48 °C.
IR (KBr): 2922, 2368, 1622, 1502, 1459, 1341, 1267, 1074, 821, 753
cm–1
.
1H NMR (300 MHz, CDCl3): δ = 8.17 (d, J = 8.4 Hz, 1 H), 7.69 (q, J = 8.4
Hz, 2 H), 7.49 (t, J = 7.8 Hz, 1 H), 7.32 (t, J = 8.4 Hz, 1 H), 7.26 (d, J = 7.2
Hz, 1 H), 7.21–7.17 (m, 3 H), 7.06 (d, J = 7.8 Hz, 1 H), 5.19 (s, 2 H), 2.30
(s, 3 H).
13C NMR (75 MHz, CDCl3): δ = 153.0, 138.2, 136.6, 133.2, 130.0, 128.7,
128.7, 128.4, 128.0, 127.8, 127.6, 126.2, 124.5, 124.2, 115.7, 110.0,
71.9, 21.4.
Halonaphthalenyl Ethers 3a–p and 7; General Procedure
To a solution of diazo compound 1a–e or 6 (1 mmol) and benzyl ha-
lide 2a–e (10 mmol) in PhF (5 mL) was added Rh2(OPiv)4 (2 mol%).
The mixture was stirred under N2 at r.t. for 15–18 h. Then, the solvent
was evaporated on a rotary evaporator under reduced pressure. The
residue thus obtained was purified by flash column chromatography
(silica gel) to isolate the product.
HRMS (EI): m/z [M+] calcd for C18H15BrO: 326.0306; found: 326.0307.
1-Bromo-2-(4-methylbenzyloxy)naphthalene (3c)
Solid; yield: 196 mg (62%); mp 112–114 °C.
IR (KBr): 2923, 2372, 1622, 1504, 1452, 1340, 1268, 1070, 805, 742
cm–1
.
2-(Benzyloxy)-1-bromonaphthalene (3a)
1H NMR (300 MHz, CDCl3): δ = 8.16 (d, J = 8.4 Hz, 1 H), 7.68 (t, J = 8.4
Hz, 2 H), 7.48 (t, J = 7.8 Hz, 1 H), 7.33–7.30 (m, 2 H), 7.19 (d, J = 9.0 Hz,
2 H), 7.12 (d, J = 7.2 Hz, 2 H), 5.19 (s, 2 H), 2.28 (s, 3 H).
13C NMR (75 MHz, CDCl3): δ = 153.0, 137.7, 133.6, 133.1, 130.0, 129.2,
128.7, 127.9, 127.6, 127.3, 126.2, 124.4, 115.7, 110.0, 71.8, 21.1.
Solid; yield: 218 mg (70%); mp 105–107 °C.
IR (KBr): 3061, 2364, 1625, 1501, 1343, 1266, 1052, 802, 749 cm–1
1H NMR (300 MHz, CDCl3): δ = 8.15 (d, J = 8.7 Hz, 1 H), 7.68–7.64 (m, 2
H), 7.50–7.42 (m, 3 H), 7.30 (t, J = 6.9 Hz, 3 H), 7.24 (d, J = 7.2 Hz, 1 H),
7.16 (d, J = 8.7 Hz, 1 H), 5.20 (s, 2 H).
.
HRMS (EI): m/z [M+] calcd for C18H15BrO: 326.0306; found: 326.0304.
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2-(Benzyloxy)-1-bromo-6-methoxynaphthalene (3d)
Solid; yield: 219 mg (64%); mp 99–101 °C.
13C NMR (75 MHz, CDCl3): δ = 159.1, 153.3, 137.4, 134.4, 133.4, 129.5,
129.0, 128.8, 128.2, 127.0, 125.1, 117.1, 112.6, 104.4, 71.4, 55.1, 20.9.
HRMS (EI): m/z [M+] calcd for C19H17BrO2: 356.0412; found: 356.0414.
IR (KBr): 2925, 2371, 1597, 1497, 1456, 1344, 1256, 1029, 740, 693
cm–1
.
2-(Benzyloxy)-1,6-dibromonaphthalene (3i)
1H NMR (300 MHz, CDCl3): δ = 8.13 (d, J = 9.0 Hz, 1 H), 7.62 (d, J = 8.4
Hz, 1 H), 7.50 (d, J = 7.8 Hz, 2 H), 7.37 (t, J = 7.8 Hz, 2 H), 7.32 (t, J = 8.4
Hz, 1 H), 7.22–7.20 (m, 2 H), 7.06 (d, J = 2.4 Hz, 1 H), 5.24 (s, 2 H), 3.89
(s, 3 H).
13C NMR (75 MHz, CDCl3): δ = 156.7, 151.4, 136.8, 131.1, 128.6, 128.5,
127.9, 127.9, 127.3, 127.2, 120.3, 116.5, 110.5, 105.9, 72.1, 55.3.
Solid; yield: 280 mg (72%); mp 83–85 °C.
IR (KBr): 3064, 2369, 1582, 1490, 1456, 1334, 1272, 1060, 799, 732
cm–1
.
1H NMR (300 MHz, CDCl3): δ = 8.01 (d, J = 9.0 Hz, 1 H), 7.82 (s, 1 H),
7.57–7.50 (m, 2 H), 7.42 (d, J = 6.9 Hz, 2 H), 7.33–7.24 (m, 3 H), 7.17
(d, J = 9.0 Hz, 1 H), 5.20 (s, 2 H).
HRMS (EI): m/z [M+] calcd for C18H15BrO2: 342.0255; found: 342.0253.
13C NMR (75 MHz, CDCl3): δ = 153.1, 136.3, 131.7, 130.8, 129.7, 128.6,
1-Bromo-6-methoxy-2-(3-methylbenzyloxy)naphthalene (3e)
Solid; yield: 214 mg (60%); mp 83–85 °C.
128.1, 127.8, 127.4, 127.1, 126.7, 118.3, 115.6, 109.8, 71.6.
HRMS (EI): m/z [M+] calcd for C17H12Br2O: 389.9255; found 389.9256.
IR (KBr): 2915, 2369, 1598, 1498, 1456, 1372, 1252, 1167, 1071, 851,
793, 691 cm–1
.
1,6-Dibromo-2-(3-methylbenzyloxy)naphthalene (3j)
1H NMR (300 MHz, CDCl3): δ = 8.16 (d, J = 9.0 Hz, 1 H), 7.63 (d, J = 9.0
Hz, 1 H), 7.33 (t, J = 7.8 Hz, 2 H), 7.28 (t, J = 7.8 Hz, 1 H), 7.25–7.22 (m,
2 H), 7.14 (d, J = 7.2 Hz, 1 H), 7.08 (d, J = 1.8 Hz, 1 H), 5.22 (s, 2 H), 3.91
(s, 3 H), 2.38 (s, 3 H).
13C NMR (75 MHz, CDCl3): δ = 156.7, 151.5, 138.2, 136.7, 131.0, 128.6,
128.5, 128.4, 127.9, 127.9, 127.3, 124.3, 120.3, 116.6, 110.4, 105.9,
72.2, 55.3, 21.4.
Solid; yield: 210 mg (59%); mp 63–65 °C.
IR (KBr): 2922, 2371, 1584, 1490, 1389, 1272, 1071, 802, 691 cm–1
.
1H NMR (300 MHz, CDCl3): δ = 8.09 (d, J = 9.3 Hz, 1 H), 7.90 (d, J = 1.8
Hz, 1 H), 7.65–7.57 (m, 2 H), 7.30–7.26 (m, 4 H), 7.13–7.11 (m, 1 H),
5.24 (s, 2 H), 2.36 (s, 3 H).
13C NMR (75 MHz, CDCl3): δ = 153.3, 138.3, 136.3, 130.8, 129.8, 128.8,
128.5, 128.2, 127.8, 127.8, 126.7, 124.2, 118.3, 117.6, 116.5, 113.4,
71.8, 21.4.
HRMS (EI): m/z [M+] calcd for C19H17BrO2: 356.0412; found: 356.0410.
HRMS (EI): m/z [M+] calcd for C18H14Br2O: 403.9411; found: 403.9410.
1-Bromo-6-methoxy-2-(4-methylbenzyloxy)naphthalene (3f)
Solid; yield: 221 mg (62%); mp 105–107 °C.
1,6-Dibromo-2-(4-methylbenzyloxy)naphthalene (3k)
IR (KBr): 2924, 2370, 1598, 1458, 1372, 1252, 1125, 1028, 798, 640
Solid; yield: 222 mg (55%); mp 127–129 °C.
IR (KBr): 2926, 2357, 1556, 1510, 1451, 1382, 1265, 757, 661 cm–1
1H NMR (300 MHz, CDCl3): δ = 8.08 (d, J = 8.4 Hz, 1 H), 7.90 (s, 1 H),
7.65–7.57 (m, 2 H), 7.37 (d, J = 8.4 Hz, 2 H), 7.27–7.16 (m, 3 H), 5.24 (s,
2 H), 2.33 (s, 3 H).
13C NMR (75 MHz, CDCl3): δ = 153.2, 137.8, 133.3, 131.8, 130.8, 130.8,
129.8, 129.3, 128.2, 127.7, 127.2, 118.3, 116.5, 109.9, 71.7, 21.2.
HRMS (EI): m/z [M+] calcd for C18H14Br2O: 403.9411; found: 403.9409.
cm–1
.
.
1H NMR (300 MHz, CDCl3): δ = 8.17 (d, J = 9.6 Hz, 1 H), 7.65 (d, J = 8.7
Hz, 1 H), 7.43 (d, J = 7.8 Hz, 2 H), 7.28–7.27 (m, 1 H), 7.24–7.21 (m, 3
H), 7.10 (d, J = 2.4 Hz, 1 H), 5.24 (s, 2 H), 3.93 (s, 3 H), 2.38 (s, 3 H).
13C NMR (75 MHz, CDCl3): δ = 156.7, 151.5, 137.7, 133.8, 131.0, 129.2,
128.6, 127.9, 127.4, 127.2, 120.2, 116.7, 110.5, 106.0, 72.2, 55.3, 21.1.
HRMS (EI): m/z [M+] calcd for C19H17BrO2: 356.0412; found: 356.0408.
2-(Benzyloxy)-1-bromo-7-methoxynaphthalene (3g)
Solid; yield: 239 mg (70%); mp 84–86 °C.
1,6-Dibromo-2-(4-chlorobenzyloxy)naphthalene (3l)
Solid; yield: 255 mg (60%); mp 134–136 °C.
IR (KBr): 2923, 2368, 1564, 1511, 1472, 1380, 1260, 769, 651 cm–1
1H NMR (600 MHz, CDCl3): δ = 8.10 (d, J = 9.0 Hz, 1 H), 7.93 (d, J = 1.2
Hz, 1 H), 7.67 (d, J = 8.4 Hz, 1 H), 7.61 (dd, J = 8.4, 1.2 Hz, 1 H), 7.45 (d,
J = 9.0 Hz, 2 H), 7.37 (d, J = 8.4 Hz, 2 H), 7.25 (d, J = 1.2 Hz, 1 H), 5.25 (s,
2 H).
13C NMR (150 MHz, CDCl3): δ = 152.9, 134.9, 133.9, 131.8, 131.0,
130.9, 129.8, 128.8, 128.5, 128.2, 127.9, 118.6, 116.3, 110.1, 71.0.
HRMS (EI): m/z [M+] calcd for C17H11Br2ClO: 425.8865; found:
IR (KBr): 2927, 2380, 1627, 1509, 1455, 1381, 1264, 1221, 1030, 824,
.
732 cm–1
.
1H NMR (300 MHz, CDCl3): δ = 7.65 (q, J = 5.4 Hz, 2 H), 7.52–7.50 (m, 3
H), 7.40–7.28 (m, 3 H), 7.10 (d, J = 8.7 Hz, 1 H), 7.03 (dd, J = 8.7, 2.1 Hz,
1 H), 5.27 (s, 2 H), 3.96 (s, 3 H).
13C NMR (75 MHz, CDCl3): δ = 159.3, 153.5, 136.7, 134.6, 129.7, 128.5,
128.5, 128.4, 127.9, 127.1, 125.3, 117.4, 112.7, 104.6, 71.6, 55.3.
HRMS (EI): m/z [M+] calcd for C18H15BrO2: 342.0255; found: 342.0257.
425.8865.
1-Bromo-7-methoxy-2-(4-methylbenzyloxy)naphthalene (3h)
Solid; yield: 213 mg (60%); mp 76–78 °C.
2-(Benzyloxy)-1-bromo-3-methoxynaphthalene (3m)
IR (KBr): 2924, 2372, 1628, 1510, 1482, 1381, 1261, 1032, 816, 618
Liquid; yield: 236 mg (69%).
IR (neat): 2960, 2359, 1463, 1490, 1257, 1119, 1027, 749, 696 cm–1
1H NMR (300 MHz, CDCl3): δ = 8.17–8.14 (m, 1 H), 7.72–7.69 (m, 1 H),
7.61 (d, J = 6.6 Hz, 2 H), 7.47–7.34 (m, 5 H), 7.16 (s, 1 H), 5.12 (s, 2 H),
3.97 (s, 3 H).
cm–1
.
.
1H NMR (300 MHz, CDCl3): δ = 7.64 (q, J = 4.5 Hz, 2 H), 7.50 (d, J = 2.1
Hz, 1 H), 7.39 (d, J = 7.8 Hz, 2 H), 7.18 (q, J = 7.8 Hz, 2 H), 7.10 (d, J = 8.7
Hz, 1 H), 7.02 (dd, J = 8.7, 2.4 Hz, 1 H), 5.23 (s, 2 H), 3.95 (s, 3 H), 2.34
(s, 3 H).
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13C NMR (150 MHz, CDCl3): δ = 152.5, 146.0, 137.0, 131.6, 128.5,
1-Chloronaphthalen-2-yl Acetate (5a)
128.3, 128.1, 127.8, 126.7, 126.7, 126.0, 125.0, 116.8, 106.9, 74.8, 55.8.
HRMS (EI): m/z [M+] calcd for C18H15BrO2: 342.0255; found: 342.0255.
Solid; yield: 114 mg (52%); mp 62–64 °C.
IR (KBr): 3060, 2931, 2369, 1758, 1509, 1370, 1212, 1017, 820, 754
cm–1
.
1-Bromo-3-methoxy-2-(3-methylbenzyloxy)naphthalene (3n)
1H NMR (300 MHz, CDCl3): δ = 7.82–7.73 (m, 3 H), 7.51 (d, J = 2.1 Hz, 1
Liquid; yield: 224 mg (63%).
H), 7.45–7.41 (m, 1 H), 7.21–7.17 (m, 1 H), 2.31 (s, 3 H).
IR (neat): 2926, 2359, 1645, 1537, 1452, 1342, 1268, 804, 755 cm–1
.
13C NMR (75 MHz, CDCl3): δ = 169.6, 148.2, 133.7, 131.4, 129.3, 127.7,
1H NMR (300 MHz, CDCl3): δ = 8.25–8.22 (m, 1 H), 7.79–7.76 (m, 1 H),
7.54–7.46 (m, 4 H), 7.39–7.31 (m, 1 H), 7.24–7.22 (m, 2 H), 5.15 (s, 2
H), 4.06 (s, 3 H), 2.47 (s, 3 H).
127.6, 126.5, 125.6, 121.0, 118.4, 21.1.
HRMS (EI): m/z [M+] calcd for C12H9ClO2: 220.0291; found: 220.0292.
13C NMR (75 MHz, CDCl3): δ = 152.6, 146.1, 137.9, 137.0, 131.6, 129.1,
128.8, 128.2, 127.9, 126.7, 126.7, 126.0, 125.5, 125.0, 116.8, 106.9,
74.9, 55.9, 21.4.
1-Chloro-6-methoxynaphthalen-2-yl Acetate (5b)
Solid; yield: 140 mg (56%); mp 79–81 °C.
IR (KBr): 2999, 2940, 2834, 1750, 1602, 1365, 1198, 1018, 853, 816,
HRMS (EI): m/z [M+] calcd for C19H17BrO2: 356.0412; found: 356.0408.
711 cm–1
.
1H NMR (600 MHz, CDCl3): δ = 8.15 (d, J = 9.0 Hz, 1 H), 7.56 (d, J = 9.0
Hz, 1 H), 7.27 (dd, J = 9.0, 2.4 Hz, 1 H), 7.21 (d, J = 9.0 Hz, 1 H), 7.13 (d,
J = 2.4 Hz, 1 H), 3.92 (s, 3 H), 2.40 (s, 3 H).
2-(Benzyloxy)-6-bromo-1-chloronaphthalene (3o)
Solid; yield: 197 mg (57%); mp 66–68 °C.
IR (KBr): 2926, 2359, 1645, 1537, 1452, 1342, 1268, 804, 755 cm–1
.
13C NMR (75 MHz, CDCl3): δ = 168.9, 158.0, 142.9, 133.7, 129.0, 126.6,
1H NMR (300 MHz, CDCl3): δ = 8.08 (d, J = 8.7 Hz, 1 H), 7.91 (d, J = 1.8
Hz, 1 H), 7.60 (d, J = 8.7 Hz, 2 H), 7.49–7.46 (m, 2 H), 7.40–7.27 (m, 4
H), 5.28 (s, 2 H).
126.4, 125.9, 122.2, 120.2, 106.2, 55.4, 20.7.
HRMS (EI): m/z [M+] calcd for C13H11ClO3: 250.0397; found: 250.0400.
13C NMR (150 MHz, CDCl3): δ = 151.8, 136.2, 130.4, 130.3, 129.6,
128.7, 128.5, 128.4, 127.9, 126.9, 126.6, 125.3, 118.2, 116.4, 71.5.
HRMS (EI): m/z [M+] calcd for C17H12BrClO: 345.9760; found:
345.9761.
1-Chloro-7-methoxynaphthalen-2-yl Acetate (5c)
Solid; yield: 145 mg (58%); mp 69–71 °C.
IR (KBr): 3009, 2905, 2855, 1763, 1628, 1510, 1360, 1188, 1023, 896,
846, 677 cm–1
.
1H NMR (600 MHz, CDCl3): δ = 7.70 (d, J = 9.0 Hz, 1 H), 7.67 (d, J = 8.4
Hz, 1 H), 7.49 (d, J = 2.4 Hz, 1 H), 7.15 (dd, J = 9.0, 2.4 Hz, 1 H), 7.10 (d,
J = 9.0 Hz, 1 H), 3.94 (s, 3 H), 2.40 (s, 3 H).
2-(Benzyloxy)-1-chloro-3-methoxynaphthalene (3p)
Liquid; yield: 179 mg (60%).
IR (neat): 2930, 2354, 1643, 1463, 1329, 1260, 761, 645 cm–1
.
13C NMR (150 MHz, CDCl3): δ = 168.6, 159.1, 145.2, 132.8, 129.7,
1H NMR (300 MHz, CDCl3): δ = 8.15–8.12 (m, 1 H), 7.72–7.67 (m, 1 H),
7.57 (d, J = 6.6 Hz, 2 H), 7.45–7.29 (m, 5 H), 7.11 (s, 1 H), 5.11 (s, 2 H),
3.97 (s, 3 H).
127.7, 127.5, 121.6, 119.2, 119.0, 102.5, 55.3, 20.7.
HRMS (EI): m/z [M+] calcd for C13H11ClO3: 250.0397; found: 250.0399.
13C NMR (150 MHz, CDCl3): δ = 152.6, 144.7, 137.0, 131.2, 128.6,
128.5, 128.3, 128.1, 126.7, 126.0, 124.8, 124.1, 116.1, 106.0, 75.1, 55.9.
HRMS (EI): m/z [M+] calcd for C18H15ClO2: 298.0761; found: 298.0758.
6-Bromo-1-chloronaphthalen-2-yl Acetate (5d)
Solid; yield: 178 mg (60%); mp 110–112 °C.
IR (KBr): 3057, 2928, 2364, 1750, 1512, 1372, 1213, 1019, 820, 753
cm–1
.
1-(Benzyloxy)-2-bromonaphthalene (7)
1H NMR (300 MHz, CDCl3): δ = 7.98 (s, 1 H), 7.74 (d, J = 9.0 Hz, 1 H),
7.65 (d, J = 9.0 Hz, 1 H), 7.53 (td, J = 9.0, 1.8 Hz, 2 H), 2.33 (s, 3 H).
Solid; yield: 172 mg (55%); mp 48–50 °C.
IR (KBr): 3059, 2367, 1604, 1510, 1368, 1210, 1017, 820, 750 cm–1
.
13C NMR (150 MHz, CDCl3): δ = 169.4, 148.5, 132.4, 132.1, 129.9,
1H NMR (300 MHz, CDCl3): δ = 8.12–8.09 (m, 1 H), 7.80 (s, 1 H), 7.62–
129.8, 129.2, 128.5, 122.2, 119.6, 118.6, 21.1.
HRMS (EI): m/z [M+] calcd for C12H8BrClO2: 297.9396; found:
7.59 (m, 3 H), 7.53–7.37 (m, 6 H), 5.12 (s, 2 H).
13C NMR (150 MHz, CDCl3): δ = 151.9, 136.8, 133.9, 130.1, 129.3,
297.9394.
128.5, 128.3, 128.2, 128.0, 126.7, 126.5, 125.4, 122.1, 113.1, 75.6.
1-Bromo-6-methoxynaphthalen-2-yl Benzoate (5e)
Solid; yield: 185 mg (52%); mp 149–151 °C.
HRMS (EI): m/z [M+] calcd for C17H13BrO: 312.0150; found: 312.0149.
Chloronaphthalenyl Esters 5a–e and 8; General Procedure
IR (KBr): 3009, 2936, 2851, 1763, 1628, 1506, 1452, 1375, 1172, 1126,
1018, 896, 835, 712, 677 cm–1
.
To a solution of diazo compounds 1a–d, or 6 (1 mmol) and acetyl
chloride (4a) or benzoyl bromide (4b) (10 mmol) in PhF (5 mL) was
added Rh2(OPiv)4 (2 mol%). The mixture was stirred under N2 for 17 h.
Then, the remaining acetyl chloride was evaporated on a rotary evap-
orator under reduced pressure. The residue thus obtained was puri-
fied by flash column chromatography (silica gel) to isolate the prod-
uct.
1H NMR (600 MHz, CDCl3): δ = 8.29 (d, J = 7.2 Hz, 2 H), 8.16 (d, J = 9.0
Hz, 1 H), 7.73 (d, J = 9.0 Hz, 1 H), 7.65 (t, J = 7.2 Hz, 1 H), 7.53 (t, J = 8.4
Hz, 2 H), 7.33 (d, J = 9.0 Hz, 1 H), 7.26 (dd, J = 9.0, 2.4 Hz, 1 H), 7.14 (d,
J = 2.4 Hz, 1 H), 3.92 (s, 3 H).
13C NMR (150 MHz, CDCl3): δ = 164.6, 157.9, 144.7, 133.8, 133.7,
130.4, 129.1, 128.6, 128.5, 127.9, 127.4, 122.3, 120.4, 114.9, 106.2,
55.4.
HRMS (EI): m/z [M+] calcd for C18H13BrO3: 356.0048; found: 356.0048.
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2-Chloronaphthalen-1-yl Acetate (8)
IR (neat): 3048, 2935, 2301, 1725, 1598, 1501, 1371, 1240, 1039, 772,
969 cm–1
.
Solid; yield: 114 mg (52%); mp 42–44 °C.
1H NMR (300 MHz, CDCl3): δ = 7.71 (d, J = 9.0 Hz, 1 H), 7.50–7.31 (m, 7
H), 7.16–7.11 (m, 2 H), 7.02 (d, J = 9.0 Hz, 2 H), 6.94 (d, J = 7.8 Hz, 2 H),
4.98 (s, 2 H), 3.89 (s, 3 H), 2.26 (s, 3 H).
13C NMR (75 MHz, CDCl3): δ = 156.2, 151.5, 137.9, 137.3, 136.5, 131.0,
130.5, 128.9, 128.2, 128.1, 128.0, 127.8, 127.5, 127.5, 127.1, 127.0,
124.0, 118.9, 117.3, 105.7, 72.3, 55.3, 21.3.
IR (KBr): 3058, 2930, 2366, 1752, 1504, 1372, 1210, 1019, 820, 750
cm–1
.
1H NMR (300 MHz, CDCl3): δ = 7.81 (t, J = 9.3 Hz, 2 H), 7.68 (d, J = 8.7
Hz, 1 H), 7.56–7.46 (m, 3 H), 2.49 (s, 3 H).
13C NMR (150 MHz, CDCl3): δ = 168.1, 142.8, 132.9, 128.0, 127.9,
127.3, 126.9, 126.6, 123.6, 121.9, 121.0, 20.5.
HRMS (EI): m/z [M+] calcd for C25H22O2: 354.1620; found: 354.1619.
HRMS (EI): m/z [M+] calcd for C12H9ClO23: 220.0291; found: 220.0290.
6-Methoxy-1-(3-methoxyphenyl)-2-(3-methylbenzyloxy)naphtha-
lene (13e)
Polyaromatic Compounds 13a–f; General Procedure
To a solution of halonaphthalenyl ether 3a, 3e, and 3i (1 mmol) and
phenylboronic acid 12a–c (1.1 mmol or 2.2 mmol) in toluene (5 mL)
and K2CO3 (2 M) was added Pd(PPh3)4 (5 mol%) and the mixture was
refluxed for 16–20 h. The mixture was quenched with sat. NH4Cl solu-
tion (10 mL) and extracted with EtOAc (3 × 10 mL). The solvent was
evaporated on a rotary evaporator under reduced pressure. The resi-
due thus obtained was purified by flash column chromatography (sil-
ica gel) to isolate the product.
Solid; yield: 299 mg (78%); mp 72–74 °C.
IR (KBr): 3052, 2925, 2340, 1714, 1596, 1449, 1250, 1056, 749 cm–1
.
1H NMR (300 MHz, CDCl3): δ = 7.73 (d, J = 9.0 Hz, 1 H), 7.53 (d, J = 9.3
Hz, 1 H), 7.43 (t, J = 8.1 Hz, 1 H), 7.35 (d, J = 8.7 Hz, 1 H), 7.20–7.14 (m,
2 H), 7.08–6.99 (m, 7 H), 5.03 (s, 2 H), 3.91 (s, 3 H), 3.83 (s, 3 H), 2.30
(s, 3 H).
13C NMR (75 MHz, CDCl3): δ = 159.3, 156.2, 151.4, 137.9, 137.8, 137.3,
130.4, 128.9, 128.8, 128.2, 128.0, 127.8, 127.5, 127.2, 127.1, 124.0,
123.4, 118.9, 117.2, 116.3, 112.8, 105.7, 72.1, 55.2, 55.1, 21.2.
2-(Benzyloxy)-1-phenylnaphthalene (13a)
Liquid; yield: 217 mg (70%).
IR (neat): 3050, 2922, 2344, 1723, 1596, 1455, 1257, 1057, 742 cm–1
HRMS (EI): m/z [M+] calcd for C26H24O3: 384.1725; found: 384.1726.
.
1H NMR (300 MHz, CDCl3): δ = 7.61 (d, J = 8.7 Hz, 2 H), 7.34–7.26 (m, 4
H), 7.21–7.11 (m, 5 H), 7.05–7.03 (m, 3 H), 6.96 (d, J = 7.2 Hz, 2 H),
4.87 (s, 2 H).
13C NMR (150 MHz, CDCl3): δ = 152.8, 137.3, 136.3, 133.6, 131.0,
129.4, 129.1, 128.9, 128.3, 128.0, 127.8, 127.5, 127.0, 126.9, 126.2,
125.4, 123.8, 116.3, 71.7.
2-(Benzyloxy)-1,6-diphenylnaphthalene (13f)
Solid; yield: 282 mg (73%); mp 128–130 °C.
IR (KBr): 3052, 2940, 2354, 1722, 1560, 1443, 1260, 1043, 749 cm–1
.
1H NMR (300 MHz, CDCl3): δ = 7.94 (s, 1 H), 7.82 (d, J = 9.0 Hz, 1 H),
7.61 (d, J = 7.2 Hz, 2 H), 7.53 (s, 2 H), 7.46–7.25 (m, 10 H), 7.20–7.19
(m, 2 H), 7.12–7.09 (m, 2 H), 5.02 (s, 2 H).
13C NMR (75 MHz, CDCl3): δ = 152.9, 141.0, 137.2, 136.5, 136.3, 132.8,
131.0, 129.6, 129.2, 128.8, 128.3, 128.1, 127.5, 127.2, 127.1, 127.1,
126.9, 126.8, 126.0, 125.9, 125.6, 116.7, 71.7.
HRMS (EI): m/z [M+] calcd for C23H18O: 310.1358; found: 310.1359.
2-(Benzyloxy)-1-(3-methoxyphenyl)naphthalene (13b)
Liquid; yield: 205 mg (72%).
IR (neat): 3052, 2925, 2340, 1720, 1596, 1450, 1250, 1053, 743 cm–1
HRMS (EI): m/z [M+] calcd for C29H22O: 386.1671; found: 386.1668.
.
1H NMR (300 MHz, CDCl3): δ = 7.70–7.67 (m, 2 H), 7.44–7.42 (m, 1 H),
7.28 (t, J = 7.8 Hz, 1 H), 7.22–7.21 (m, 3 H), 7.15–7.11 (m, 3 H), 7.07 (d,
J = 7.8 Hz, 2 H), 6.87 (d, J = 7.2 Hz, 2 H), 6.82 (s, 1 H), 4.97 (s, 2 H), 3.69
(s, 3 H).
13C NMR (75 MHz, CDCl3): δ = 159.4, 152.7, 137.7, 137.3, 133.5, 129.3,
129.0, 129.0, 128.3, 127.7, 127.5, 127.0, 126.7, 126.2, 125.4, 123.8,
123.5, 116.3, 116.3, 113.0, 71.7, 55.2.
Acknowledgment
This work was supported by the 2014 Yeungnam University Research
Grant (214A380008).
Supporting Information
HRMS (EI): m/z [M+] calcd for C24H20O2: 340.1463; found: 340.1462.
Supporting information for this article is available online at
http://dx.doi.org/10.1055/s-0035-1561295.
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2-(Benzyloxy)-1-(3,5-dimethoxyphenyl)naphthalene (13c)
Solid; yield: 285 mg (77%); mp 85–87 °C.
IR (KBr): 3050, 2920, 2340, 1724, 1590, 1450, 1251, 1052, 742 cm–1
.
References
1H NMR (300 MHz, CDCl3): δ = 7.72–7.70 (m, 2 H), 7.52–7.51 (m, 1 H),
7.26–7.25 (m, 3 H), 7.20–7.17 (m, 2 H), 7.15 (d, J = 7.8 Hz, 3 H), 6.47 (s,
3 H), 5.03 (s, 2 H), 3.70 (s, 6 H).
13C NMR (75 MHz, CDCl3): δ = 160.5, 152.6, 138.4, 137.3, 133.5, 132.3,
129.3, 128.9, 128.4, 128.3, 127.7, 127.5, 127.0, 126.7, 126.3, 125.5,
123.8, 116.2, 108.9, 99.6, 71.7, 55.2.
(1) (a) Edlund, C.; Ganning, A. E.; Elhammer, A. Acta Chem. Scand. B
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HRMS (EI): m/z [M+] calcd for C25H22O3: 370.1569; found: 370.1567.
6-Methoxy-2-(3-methylbenzyloxy)-1-phenylnaphthalene (13d)
Liquid; yield: 251 mg (71%).
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