ZnI2-Catalyzed benzannulation of o-alkynylbenzaldehydes with alkenes leading to 1-acyl-2-substituted naphthalenes

Article abstract of DOI:10.1002/ejoc.201000497

A new, practical route to 1-acyl-2-substituted naphthalenes has been developed by benzoquinone-promoted ZnI₂-catalyzed benzannulation of 2-alkynylbenzaldehydes with alkenes. This method allows three new bonds, two C=C bonds and one C=O bond, to be constructed in a single reaction.

Full text of DOI:10.1002/ejoc.201000497

FULL PAPER
DOI: 10.1002/ejoc.201000497
ZnI2-Catalyzed Benzannulation of o-Alkynylbenzaldehydes with Alkenes
Leading to 1-Acyl-2-Substituted Naphthalenes
Xia Zhao,[a] Xing-Guo Zhang,[a] Ri-Yuan Tang,[a] Chen-Liang Deng,[a] and Jin-Heng Li*[a,b]
Keywords: Zinc / Annulation / Fused-ring systems / Alkenes
A new, practical route to 1-acyl-2-substituted naphthalenes
enes. This method allows three new bonds, two C=C bonds
has been developed by benzoquinone-promoted ZnI2-cata- and one C=O bond, to be constructed in a single reaction.
lyzed benzannulation of 2-alkynylbenzaldehydes with alk-
With continuing interest in zinc chemistry,[15] we decide to
Introduction
explore the efficiency of zinc Lewis acids in the [4+2] cyclo-
The naphthalene ring is a prominent structural motif
addition transformation. Here, we report a new, practical,
found in a wide range of biologically active natural prod-
ZnI2-catalyzed benzannulation protocol for the synthesis of
ucts, pharmaceuticals, and materials.[1] Techniques com-
1-acyl-2-arylnaphthalenes (Scheme 1, Equation 2). It is
monly used to prepare naphthalene or its derivatives in-
noteworthy that the Zn-catalyzed protocol has different
clude (i) introduction of substituents onto the preexisting
selectivity, particularly in the presence of 1,4-benzoquinone,
naphthalene ring,[2] (ii) Diels–Alder reactions and [2+2+2]
from that reported for the Cu- or Au-catalyzed transforma-
cyclotrimerization of alkynes, and (iii) [4+2] benzannulation
tions.
of enynes.[2–7] However, these methods involve the use of
relatively harsh reaction conditions, inaccessible substrates,
and/or expensive catalysts. Alternatively, Lewis acid cata-
lyzed benzannulation of alkynylbenzaldehydes with unsatu-
rated compounds (alkynes or alkenes) has been recently em-
ployed as an efficient strategy to access naphthalene and
its derivatives.[8–14] However, only a few papers have been
reported, and the catalysts used are limited to Au or Cu
Lewis acids.[8–13] For example, Asao and Yamamoto dis-
closed an efficient route to naphthalenes by gold-catalyzed
[4+2] cycloaddition of o-alkynylbenzaldehydes with alk-
ynes.[8] Subsequently, they described another Cu(OTf)2-
catalyzed [4+2] cycloaddition approach to 1,2-dihydronaph-
thalenes by using o-alkynyl(oxo)benzenes and alkenes as the
reaction partners (Scheme 1, Equation 1).[9] Dyker and co-
workers also provided similar results by using AuCl3 cataly-
sis.[10] Although Yao and co-workers reported a metal-free
transformation for the synthesis of 2,3-dihydrophen-
anthren-4(1H)-one derivatives recently, an excess amount of
Brønsted acids was required to promote the cationic cas-
cade reactions of o-alkynylbenzaldehydes with alkenes.[14]
Scheme 1. The [4+2] cycloaddition reactions.
Results and Discussion
We began our study with the reaction between 2-(2-phen-
ylethynyl)benzaldehyde (1a) and 4-methylstyrene (2a) in tol-
uene to explore the optimal reaction conditions. As shown
in Table 1, a series of zinc halides were initially tested
(Table 1, Entries 1–4). Whereas ZnF2 gave a trace amount
of target cycloaddition products 3 and 4 (Table 1, Entry 1),
ZnCl2 enhanced the yield to 57% with a 74:26 ratio of 3/4
(Table 1, Entry 2). To our delight, 82% total yield of prod-
ucts 3 and 4 was obtained in the presence of ZnI2 (Table 1,
Entry 4); however, a mixture of products 3 and 4 is unat-
tractive in organic synthesis. After a series of trials, we
found that Pd/C or 1,4-benzoquinone could improve the
selectivity.[16] In the presence of ZnI2 and Pd/C, the selectiv-
ity was shifted toward 3 (3/4 = 84:16; Table 1, Entry 5). Al-
though the yield had decreased to 55%, product 4 was ob-
[a] College of Chemistry and Materials Science, Wenzhou
University,
Wenzhou 325035, China
[b] Key Laboratory of Chemical Biology & Traditional Chinese
Medicine Research (Ministry of Education), Hunan Normal
University,
Changsha 410081, China
Fax: +86-731-8887-2531
E-mail: jhli@hunnu.edu.cn
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejoc.201000497.
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X. Zhao, X.-G. Zhang, R.-Y. Tang, C.-L. Deng, J.-H. Li
FULL PAPER
tained alone with the use of 1,4-benzoquinone as an addi- phatic groups disfavored the reaction (Table 2, Entries 10
tive (Table 1, Entry 6). The results demonstrated a solvent and 13), whereas electron-deficient aryl groups were satis-
effect (Table 1, Entries 6–9). DMSO was found to be a un- factory for the reaction (Table 2, Entries 11 and 12). Sub-
suitable solvent (Table 1, Entry 7), and HOAc was superior
to toluene (Table 1, Entry 8). It was pleasing to disclose that
a mixed solvent, toluene/HOAc, afforded product 4 in 81%
Table 2. ZnI2-catalyzed benzannulation reactions of o-alkynylbenz-
aldehydes (1) with alkenes (2) in the presence of 1,4-benzoquin-
one.[a]
yield (Table 1, Entry 9). Among both the reaction tempera-
ture and the amount of ZnI2 examined, it turned out that
30 mol-% of ZnI2 at 120 °C gave the best results (Table 1,
Entries 9–13). We also found that the amount of 1,4-benzo-
quinone had an effect on the reaction, and 1 equiv. of 1,4-
benzoquinone lowered the yield to 63% (Table 1, Entry 14).
Table 1. Screening optimal conditions.[a]
Entry
[Zn] (equiv.)
Solvent
Additive
T
[°C]
Yield
[%][b]
1
2
3
ZnF2 (30)
ZnCl2 (30)
ZnBr2 (30)
ZnI2 (30)
ZnI2 (30)
ZnI2 (30)
ZnI2 (30)
ZnI2 (30)
ZnI2 (30)
ZnI2 (30)
ZnI2 (30)
ZnI2 (20)
ZnI2 (10)
ZnI2 (30)
toluene
toluene
toluene
toluene
toluene
toluene
DMSO
HOAc
–
–
–
–
80
80
80
80
80
80
80
80
80
60
trace
57 (74:26)
70 (55:45)
82 (74:26)
80 (84:16)
55 (0:100)
trace
69 (0:100)
81 (0:100)
64 (0:100)
4
5[c]
6
–
BQ
BQ
BQ
BQ
BQ
BQ
BQ
BQ
BQ
7
8
9[d]
10[d]
11[d]
12[d]
13[d]
14[d,e]
toluene/HOAc
toluene/HOAc
toluene/HOAc
toluene/HOAc
toluene/HOAc
toluene/HOAc
120 88 (0:100)
120 72 (0:100)
120 47 (0:100)
120 63 (0:100)
[a] Reaction conditions: 1 (0.3 mmol), 2 (1.2 equiv.), [Zn], BQ
(2.0 equiv.) in solvent (1.25 mL) for 24 h. [b] Isolated yield. The
selectivity between products 3 and 4 is given in parenthesis. [c] Pd/C
(10 mol-%) was added. [d] Toluene/HOAc = 4:1 (1.25 mL). [e] BQ
(1 equiv.) was used.
The above results prompted us to explore both o-alkynyl-
benzaldehydes and alkenes in the tandem benzannulation–
dehydrogenation reaction under the standard conditions
(Table 2). Initially, a variety of alkenes 2b–j were employed
to react with 2-(phenylethynyl)benzaldehyde (1a) in the
presence of ZnI2 and 1,4-benzoquinone (Table 2, Entries 1–
10). We found that aryl alkenes were more active than ali-
phatic alkenes, and substituents on the aryl moiety affected
the reaction: electron-donating groups were found to be su-
perior to electron-withdrawing groups (Table 2, Entries 1–
9). Whereas 1-methoxy-4-vinylbenzene (2e), for instance,
underwent the reaction with substrate 1a, ZnI2, and 1,4-
benzoquinone smoothly in 78% yield (Table 2, Entry 4),
substrate 2g bearing a nitro group gave a lower yield of
38%. For aliphatic alkene 2j, a low yield was observed un-
der the same conditions (Table 2, Entry 9). Subsequently,
the effect of substituents at the terminal end of the 2-ethyn-
ylbenzaldehydes was investigated (Table 2, Entries 10–13).
The results showed that both electron-rich aryl and ali-
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ZnI2-Catalyzed Benzannulation of o-Alkynylbenzaldehydes
Table 2. (Continued)
1-methyl-4-vinylbenzene, ZnI2, and 1,4-benzoquinone af-
forded the corresponding product in 45 or 55% yield,
respectively (Table 2, Entries 14 and 15), whereas weak elec-
tron-withdrawing substrate 1e could react with alkene 2a in
good yield (Table 2, Entry 16). Moderate yields were still
achieved from the reaction of substrate 1e with other al-
kenes (Table 2, Entries 17–20). However, attempts to react
substrate 1a with 1,2-diphenylethene was not successful. It
is noteworthy that the structure of 8 was unambiguously
confirmed by X-ray single-crystal diffraction analysis (Fig-
ure 1).[17]
Figure 1. ORTEP diagram of the single-crystal X-ray structure of
compound 8.[17]
A plausible mechanism as outlined in Scheme 2 was pro-
posed for the present reaction on the basis of the present
results and the reported mechanism.[8–14] The coordination
of the triple bond of substrate 1 to ZnI2 enhances the elec-
trophilicity of the alkyne, leading to intermediate A, and
then nucleophilic attack of the carbonyl oxygen atom to the
electron-deficient alkyne in intermediate A gives intermedi-
ate B. The Diels–Alder reaction of intermediate B with sty-
rene 2 affords intermediate D through intermediate C. As a
result of the instability of intermediate D, the cleavage of
the carbon–oxygen bond takes place, followed by elimi-
nation of a proton to produce zinc-enolate E and HI. Inter-
mediate E can proceed through two steps together with the
regeneration of the active Zn catalyst: (1) protonation to
[a] Reaction conditions: 1 (0.3 mmol), 2 (1.2 equiv.), ZnI2 (30 mol-
%), 1,4-benzoquinone (BQ, 2.0 equiv.) in toluene/HOAc (4:1,
1.25 mL) at 120 °C. [b] Isolated yield.
stituents on the aromatic ring of the benzaldehyde moiety
were also examined (Table 2, Entries 14–20). Treatment of
substrate 1e or 1f, having an electron-donating group, with Scheme 2. A possible mechanism.
Eur. J. Org. Chem. 2010, 4211–4217
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X. Zhao, X.-G. Zhang, R.-Y. Tang, C.-L. Deng, J.-H. Li
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CDCl3): δ = 8.01 (d, J = 8.5 Hz, 1 H, Ar-H), 7.94 (d, J = 7.8 Hz,
1 H, Ar-H), 7.74–7.65 (m, 3 H, Ar-H), 7.59–7.37 (m, 4 H, Ar-H),
7.29–7.22 (m, 4 H, Ar-H), 7.05 (d, J = 7.8 Hz, 2 H, Ar-H), 2.26 (s,
3 H, -CH3) ppm. 13C NMR (75 MHz, CDCl3): δ = 199.8, 137.9,
137.4, 137.3, 137.2, 135.5, 133.2, 132.3, 130.7, 129.6, 129.4, 129.3,
129.0, 128.3, 128.2, 127.8, 127.1, 126.2, 125.5, 21.1 ppm. IR (KBr):
give 3 and (2) dehydrogenation to yield 4. 1,4-benzoquinone
is required for the dehydrogenation of intermediate E, lead-
ing to target product 4.[16]
Conclusions
ν = 2917, 1734, 1664, 1529 cm–1. LRMS (EI, 70 eV): m/z (%) = 322
˜
(41) [M]+, 245 (39), 219 (100), 202 (30), 105 (84).
In summary, we have developed the first example of the
Zn-catalyzed benzannulation of o-alkynylbenzaldehydes
with alkenes for the synthesis of 1-acyl-2-substituted naph-
thalenes. In the presence of ZnI2 and 1,4-benzoquinone, a
variety of o-alkynylbenzaldehydes successfully underwent
the reaction with alkenes to selectively prepare 1-acyl-2-
substituted arylnaphthalenes in moderate to good yields.
The present tandem benzannulation–dehydrogenation reac-
tion represents a practical route to the naphthalene skel-
eton. On the basis of the results, several features should be
noted: (1) The selectivity is different from that reported for
Cu- or Au-catalyzed transformations. (2) Two C=C bonds
and one C=O bond were formed in a single reaction.
(3) 1,4-Benzoquinone can shift the selectivity to improve
the reaction.
Phenyl(2-m-tolylnaphthalen-1-yl)methanone (5): Following the ge-
neral procedure, the title compound was obtained in 79% yield
(76 mg). Yellow oil. 1H NMR (300 MHz, CDCl3): δ = 8.01 (d, J =
8.5 Hz, 1 H, Ar-H), 7.94 (d, J = 8.6 Hz, 1 H, Ar-H), 7.75 (d, J =
8.5 Hz, 1 H, Ar-H), 7.65–7.60 (m, 2 H, Ar-H), 7.58 (d, J = 8.5 Hz,
1 H, Ar-H), 7.56–7.40 (m, 3 H, Ar-H), 7.27–7.10 (m, 5 H, Ar-H),
6.98 (d, J = 7.5 Hz, 1 H, Ar-H), 2.25 (s, 3 H, -CH3) ppm. 13C NMR
(75 MHz, CDCl3): δ = 199.7, 140.1, 138.1, 137.7, 137.6, 135.6,
133.1, 132.4, 130.7, 130.3, 129.5, 129.4, 128.3 (2 C), 128.2, 128.1,
127.6, 127.2, 126.6, 126.2, 125.6, 21.3 ppm. IR (KBr): ν = 2922,
˜
1667, 1255 cm–1. LRMS (EI, 70 eV): m/z (%) = 322 (100) [M]+, 307
(35), 256 (14), 245 (96), 201 (27). HRMS (EI) for C24H18O [M]+
calcd. 322.1352; found 322.1355.
Phenyl(2-phenylnaphthalen-1-yl)methanone (6):[18] Following the ge-
neral procedure, the title compound was obtained in 76% yield
(70 mg). Yellow oil. 1H NMR (300 MHz, CDCl3): δ = 8.02 (d, J =
8.5 Hz, 1 H, Ar-H), 7.94 (d, J = 9.2 Hz, 1 H, Ar-H), 7.74 (d, J =
8.2 Hz, 1 H, Ar-H), 7.64–7.41 (m, 5 H, Ar-H), 7.38–7.34 (m, 3 H,
Ar-H), 7.25–7.16 (m, 5 H, Ar-H) ppm. 13C NMR (125 MHz,
CDCl3): δ = 199.7, 140.2, 137.9, 137.5, 135.7, 133.3, 132.5, 130.7,
129.6, 129.5, 128.8, 128.3, 128.2, 128.0, 127.6, 127.5, 127.3, 126.4,
Experimental Section
General Remarks: NMR spectroscopy was performed with a
Bruker-300 spectrometer operating at 300 MHz (1H NMR) and
75 MHz (13C NMR). TMS (tetramethylsilane) was used an internal
standard and CDCl3 was used as the solvent. Mass spectrometric
analysis was performed by GC–MS analysis (SHIMADZU GC–
MS-QP2010 plus).
125.6 ppm. IR (KBr): ν = 2937, 1727, 1580 cm–1. LRMS (EI,
˜
70 eV): m/z (%) = 308 (99) [M]+, 231 (100), 202 (52), 105 (29), 77
(35).
[2-(4-Methoxyphenyl)naphthalen-1-yl](phenyl)methanone (7):[18] Fol-
lowing the general procedure, the title compound was obtained in
77% yield (78 mg). Yellow solid, m.p. 186.4–189.1 °C. 1H NMR
(300 MHz, CDCl3): δ = 7.99 (d, J = 8.5 Hz, 1 H, Ar-H), 7.92 (d,
J = 8.0 Hz, 1 H, Ar-H), 7.70 (d, J = 8.2 Hz, 1 H, Ar-H), 7.62 (d,
J = 8.4 Hz, 2 H, Ar-H), 7.56–7.37 (m, 4 H, Ar-H), 7.29–7.21 (m,
4 H, Ar-H), 6.75 (d, J = 8.7 Hz, 2 H, Ar-H), 3.72 (s, 3 H,
-OCH3) ppm. 13C NMR (75 MHz, CDCl3): δ = 199.9, 158.9, 137.9,
137.0, 133.2, 132.6, 132.2, 130.6 (2 C), 129.6, 129.4, 128.3 (2 C),
Typical Experimental Procedure for the Zn-Catalyzed Benzannula-
tion Reaction: To a Schlenk tube was added 1 (0.3 mmol), alkene
2 (1.2 equiv.), ZnI2 (30 mol-%), 1,4-benzoquinone (2 equiv.), and
toluene/HOAc (4:1, 1.25 mL). Then, the tube was charged with ar-
gon, and the mixture was stirred at 120 °C (oil bath temperature)
for the indicated time until complete consumption of the starting
material as monitored by TLC and GC–MS analysis. After the re-
action was finished, the reaction mixture was cooled to room tem-
perature, diluted with diethyl ether, and washed with brine. The
aqueous phase was re-extracted with EtOAc. The combined or-
ganic extracts were dried with Na2SO4 and concentrated in vacuo.
The resulting residue was purified by silica gel column chromatog-
raphy (hexane/ethyl acetate) to afford the desired product.
128.1, 127.7, 127.1, 126.1, 125.4, 113.7, 55.2 ppm. IR (KBr): ν =
˜
3309, 1663, 1517, 1237 cm–1. LRMS (EI, 70 eV): m/z (%) = 338
(100) [M]+, 261 (79), 189 (19), 105 (29).
[2-(4-Fluorophenyl)naphthalen-1-yl](phenyl)methanone (8):[18] Fol-
lowing the general procedure, the title compound was obtained in
78% yield (76 mg). Yellow solid, m.p. 180.1–182.3 °C. 1H NMR
(300 MHz, CDCl3): δ = 8.02 (d, J = 8.5 Hz, 1 H, Ar-H), 7.94 (d,
J = 7.8 Hz, 1 H, Ar-H), 7.71 (d, J = 8.5 Hz, 1 H, Ar-H), 7.60 (dd,
J = 7.8, 1.0 Hz, 2 H, Ar-H), 7.53–7.41 (m, 4 H, Ar-H), 7.33–7.22
(m, 4 H, Ar-H), 6.91 (m, 2 H, Ar-H) ppm. 13C NMR (75 MHz,
CDCl3): δ = 199.6, 162.2 (d, 1JC,F = 243.4 Hz), 137.8, 136.3, 136.22,
136.18, 135.8, 133.4, 132.4, 131.2, 131.1, 130.6, 129.5 (2 C), 128.4,
Phenyl(2-p-tolyl-1,2-dihydronaphthalen-1-yl)methanone (3):[18] Fol-
lowing the general procedure, the title compound was obtained in
67% yield (65 mg). Yellow oil. 1H NMR (300 MHz, CDCl3): δ =
7.90 (d, J = 8.7 Hz, 2 H, Ar-H), 7.57–7.51 (m, 1 H, Ar-H), 7.42
(m, 2 H, Ar-H), 7.25–7.15 (m, 3 H, Ar-H), 7.13–7.04 (m, 4 H, Ar-
H), 6.84 (d, J = 7.5 Hz, 1 H, Ar-H), 6.22 (dd, J = 9.9, 1.8 Hz, 1
H, =C-H), 5.97 (d, J = 6.6 Hz, 1 H, CH=C-H), 4.98 (d, J = 7.5 Hz,
1 H, CHC-H), 4.13 (t, J = 4.8 Hz, 1 H, =CH-C-H), 2.24 (s, 3 H,
-CH3) ppm. 13C NMR (75 MHz, CDCl3): δ = 201.0, 139.9, 137.1,
136.6, 133.7, 133.0, 131.8, 130.4, 129.6, 129.4, 128.9, 128.7 (2 C),
128.6, 128.3, 128.1, 127.7 (2 C), 127.6, 127.2, 126.6, 53.4, 43.5,
2
128.2, 127.4, 127.3, 126.4, 125.5, 115.2 (d, JC,F = 21.3 Hz) ppm.
IR (KBr): ν = 3058, 1666, 1504, 1235 cm–1. LRMS (EI, 70 eV): m/z
˜
(%) = 326 (93) [M]+, 249 (100), 220 (41), 105 (40).
[2-(4-Chlorophenyl)naphthalen-1-yl](phenyl)methanone (9): Follow-
ing the general procedure, the title compound was obtained in 41%
yield (42 mg). Yellow solid, m.p. 168.4–170.9 °C. 1H NMR
(300 MHz, CDCl3): δ = 8.01 (d, J = 8.4 Hz, 1 H, Ar-H), 7.94 (d,
J = 7.8 Hz, 1 H, Ar-H), 7.70 (d, J = 8.2 Hz, 1 H, Ar-H), 7.61 (d,
J = 7.2 Hz, 2 H, Ar-H), 7.55–7.40 (m, 4 H, Ar-H), 7.29–7.18 (m,
21.0 ppm. IR (KBr): ν = 2918, 1667, 1237 cm–1. LRMS (EI, 70 eV):
˜
m/z (%) = 324 (11) [M]+, 219 (100), 204 (42), 105 (38), 77 (29).
Phenyl(2-p-tolylnaphthalen-1-yl)methanone (4):[9] Following the ge-
neral procedure, the title compound was obtained in 88% yield
(85 mg). Yellow solid, m.p. 152.8–155.2 °C. 1H NMR (300 MHz,
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ZnI2-Catalyzed Benzannulation of o-Alkynylbenzaldehydes
6 H, Ar-H) ppm. 13C NMR (75 MHz, CDCl3): δ = 199.4, 138.6,
(75 MHz, CDCl3): δ = 199.2, 197.6, 141.0, 140.0, 137.7, 137.4,
137.7, 136.0, 135.8, 133.6, 133.5, 132.5, 130.7, 130.6, 129.6 (2 C), 137.0, 132.3, 130.5, 129.9, 129.6, 129.4, 129.1, 128.3, 128.2, 127.7,
128.4 (2 C), 128.2, 127.4, 127.3, 126.5, 125.6 ppm. IR (KBr): ν =
127.4, 126.3, 125.1, 122.4, 26.8, 21.1 ppm. IR (KBr): ν = 2921,
˜
˜
2917, 1667, 1236 cm–1. LRMS (EI, 70 eV): m/z (%) =344 (31) [M
+ 2]+, 342 (100) [M]+, 265 (79), 202 (50), 105 (56), 77 (48). HRMS
(EI) for C23H15ClO [M]+ calcd. 342.0806; found 342.0808.
1670, 1231 cm–1. LRMS (EI, 70 eV): m/z (%) = 364 (96) [M]+, 349
(24), 245 (100), 202 (41), 167 (20). HRMS (EI) for C26H20O2 [M]+
calcd. 364.1458; found 364.1459.
[2-(3-Nitrophenyl)naphthalen-1-yl](phenyl)methanone (10): Follow-
1-[4-(2-m-Tolyl-1-naphthoyl)phenyl]ethanone (17): Following the ge-
ing the general procedure, the title compound was obtained in 38%
neral procedure, the title compound was obtained in 61% yield
yield (40 mg). Yellow oil. 1H NMR (300 MHz, CDCl3): δ = 8.20 (67 mg). Yellow oil. H NMR (300 MHz, CDCl3): δ = 8.03 (d, J =
(s, 1 H, Ar-H), 8.08–8.01 (m, 2 H, Ar-H), 7.97 (d, J = 8.0 Hz, 1 H, 8.5 Hz, 1 H, Ar-H), 7.96 (d, J = 8.5 Hz, 1 H, Ar-H), 7.79 (d, J =
Ar-H), 7.73–7.67 (m, 2 H, Ar-H), 7.62–7.37 (m, 7 H, Ar-H), 7.29– 8.6 Hz, 2 H, Ar-H), 7.74–7.65 (m, 3 H, Ar-H), 7.59–7.44 (m, 3 H,
7.23 (m, 2 H, Ar-H) ppm. 13C NMR (75 MHz, CDCl3): δ = 199.0, Ar-H), 7.18–7.06 (m, 3 H, Ar-H), 6.98–6.96 (m, 1 H, Ar-H), 2.54
1
148.0, 141.8, 137.7, 136.4, 135.5, 134.7, 133.8, 132.8, 130.5, 130.0,
129.5, 129.2, 128.6, 128.3, 127.6, 127.0, 126.8, 125.7, 124.1, CDCl3): δ = 199.1, 197.5, 141.2, 139.9, 137.9, 134.9, 132.4, 130.5,
122.3 ppm. IR (KBr): ν = 2923, 1668, 1529, 1350 cm–1. LRMS (EI,
130.3, 129.9, 129.5, 128.4, 128.3, 128.2, 128.1 (2 C), 127.5, 127.4,
(s, 3 H, -COCH3), 2.24 (s, 3 H, -CH3) ppm. 13C NMR (75 MHz,
˜
70 eV): m/z (%) = 353 (100) [M]+, 276 (63), 105 (100), 77 (59). 126.6, 126.4, 125.2, 122.3, 26.8, 21.3 ppm. IR (KBr): ν = 2923,
˜
HRMS (EI) for C23H15NO3 [M]+ calcd. 353.1046; found 353.1050.
1686, 1233 cm–1. LRMS (EI, 70 eV): m/z (%) = 364 (100) [M]+,
349 (46), 245 (98), 202 (44). HRMS (EI) for C26H20O2 [M]+ calcd.
364.1458; found 364.1459.
[2-(2-Chlorophenyl)naphthalen-1-yl](phenyl)methanone (11): Follow-
ing the general procedure, the title compound was obtained in 50%
yield (51 mg). Yellow solid, m.p. 154.6–157.2 °C. 1H NMR
(300 MHz, CDCl3): δ = 8.00–7.94 (m, 2 H, Ar-H), 7.74 (d, J =
8.4 Hz, 1 H, Ar-H), 7.65 (d, J = 8.0 Hz, 2 H, Ar-H), 7.57–7.38 (m,
5 H, Ar-H), 7.38–7.23 (m, 3 H, Ar-H), 7.20–7.07 (m, 2 H, Ar-
H) ppm. 13C NMR (75 MHz, CDCl3): δ = 199.0, 137.9, 137.8,
136.7, 134.7, 133.3, 132.9, 132.7, 132.5, 130.7, 130.0, 129.5, 129.4,
129.1, 128.6, 128.2, 128.0, 127.2, 126.7, 126.2, 125.7 ppm. IR
1-(2-p-Tolylnaphthalen-1-yl)heptan-1-one (18): Following the gene-
ral procedure, the title compound was obtained in 30% yield
1
(30 mg). Yellow oil. H NMR (300 MHz, CDCl3): δ = 8.52 (d, J =
8.5 Hz, 1 H, Ar-H), 7.90–7.76 (m, 3 H, Ar-H), 7.65 (m, 2 H, Ar-
H), 7.57–7.51 (m, 1 H, Ar-H), 7.43–7.34 (m, 2 H, Ar-H), 7.19 (d,
J = 8.1 Hz, 1 H, Ar-H), 2.96 (t, J = 7.3 Hz, 2 H, -COCH2), 2.48
(s, 3 H, -CH3), 1.78 (m, 2 H, -CH2), 1.81–1.43 (m, 6 H,
-CH2CH2CH2), 0.96 (t, J = 7.1 Hz, 3 H, -CH3) ppm. 13C NMR
(75 MHz, CDCl3): δ = 210.4, 137.5, 132.5, 130.8, 129.4 (2 C), 129.3,
129.2, 128.2, 127.9, 127.7, 127.3, 127.1, 126.6, 124.8, 31.4, 28.5,
(KBr): ν = 3057, 2922, 1667, 1236 cm–1. LRMS (EI, 70 eV): m/z
˜
(%) = 344 (4) [M + 2]+, 342 (11) [M]+, 307 (100) [M – Cl]+, 202
(15), 153 (13), 77 (16). HRMS (EI) for C23H15ClO [M]+ calcd.
342.0806; found 342.0808.
23.6 (2 C), 22.4, 21.0, 14.0 ppm. IR (KBr): ν = 2925, 1698,
˜
812 cm–1. LRMS (EI, 70 eV): m/z (%) = 330 (2) [M]+, 328 (24), 300
(48), 243 (49), 229 (100), 207 (23). HRMS (EI) for C24H26O [M]+
calcd. 330.1978; found 330.1981.
[2-(2-Bromophenyl)naphthalen-1-yl](phenyl)methanone (12): Follow-
ing the general procedure, the title compound was obtained in 53%
1
yield (61 mg). Yellow oil. H NMR (300 MHz, CDCl3): δ = 8.00–
7.94 (m, 2 H, Ar-H), 7.73 (d, J = 8.4 Hz, 1 H, Ar-H), 7.67 (d, J =
(6-Methyl-2-p-tolylnaphthalen-1-yl)(phenyl)methanone (19): Follow-
5.2 Hz, 2 H, Ar-H), 7.57–7.39 (m, 5 H, Ar-H), 7.38–7.14 (m, 4 H, ing the general procedure, the title compound was obtained in 45%
Ar-H), 7.04–6.99 (m, 1 H, Ar-H) ppm. 13C NMR (75 MHz, yield (45 mg). Yellow oil. 1H NMR (300 MHz, CDCl3): δ = 7.95
CDCl3): δ = 199.0, 139.7, 137.8, 136.6, 136.1, 133.3, 132.8, 132.6,
(d, J = 8.4 Hz, 1 H, Ar-H), 7.83 (d, J = 8.4 Hz, 1 H, Ar-H), 7.65–
7.62 (m, 2 H, Ar-H), 7.50–7.47 (m, 2 H, Ar-H), 7.41–7.35 (m, 2 H,
Ar-H), 7.28–7.21 (m, 4 H, Ar-H), 7.02 (d, J = 7.8 Hz, 2 H, Ar-H),
2.41 (s, 3 H, -CH3), 2.24 (s, 3 H, -CH3) ppm. 13C NMR (75 MHz,
CDCl3): δ = 200.1, 138.0, 137.4, 137.0, 134.9, 133.1, 130.9, 130.6,
129.6, 129.3, 129.1, 128.9, 128.6, 128.5, 128.2, 127.9, 127.2, 126.8,
130.7, 129.5, 129.2, 129.0, 128.8, 128.5, 128.2, 127.7, 127.2, 126.8,
126.7, 125.7, 123.2 ppm. IR (KBr): ν = 3056, 1668, 1236 cm–1.
˜
LRMS (EI, 70 eV): m/z (%) = 388 (98) [M + 2]+, 386 (100) [M]+,
230 (11), 202 (10), 153 (15). HRMS (EI) for C23H15BrO [M]+ calcd.
386.0301; found 386.0303.
124.4, 21.9, 21.1 ppm. IR (KBr): ν = 2920, 1667, 1238, 822 cm–1.
˜
(4-Methoxyphenyl)(2-p-tolylnaphthalen-1-yl)methanone (15): Fol-
lowing the general procedure, the title compound was obtained in
40% yield (42 mg). Yellow solid, m.p. 173.9–176.8 °C. 1H NMR
(300 MHz, CDCl3): δ = 7.99 (d, J = 8.5 Hz, 1 H, Ar-H), 7.92 (d,
LRMS (EI, 70 eV): m/z (%) = 336 (100) [M]+, 321 (72), 259 (91),
149 (85), 105 (67). HRMS (EI) for C25H20O [M]+ calcd. 336.1509;
found 336.1510.
J = 8.4 Hz, 1 H, Ar-H), 7.71–7.63 (m, 3 H, Ar-H), 7.58–7.42 (m, Phenyl[6-p-tolylnaphtho(2,3-d)(1,3)dioxol-5-yl]methanone (20): Fol-
3 H, Ar-H), 7.29 (d, J = 8.1 Hz, 2 H, Ar-H), 7.06 (d, J = 7.9 Hz, lowing the general procedure, the title compound was obtained in
2 H, Ar-H), 6.74 (d, J = 9.0 Hz, 2 H, Ar-H), 3.77 (s, 3 H, -OCH3), 55% yield (60 mg). Yellow solid, m.p. 197.5–200.4 °C. 1H NMR
2.27 (s, 3 H, -CH3) ppm. 13C NMR (75 MHz, CDCl3): δ = 198.2,
163.6, 137.4, 137.0, 135.8, 132.3, 132.1, 131.2, 130.7, 129.2 (2 C),
129.1, 129.0, 128.1, 127.8, 127.0, 126.1, 125.6, 113.6, 55.4,
(300 MHz, CDCl3): δ = 7.79 (d, J = 6.9 Hz, 1 H, Ar-H), 7.63–7.59
(m, 2 H, Ar-H), 7.41–7.35 (m, 2 H, Ar-H), 7.25–7.20 (m, 5 H, Ar-
H), 7.01–6.98 (m, 3 H, Ar-H), 5.99 (s, 2 H, -OCH2O-), 2.23 (s, 3
H. -CH3) ppm. 13C NMR (75 MHz, CDCl3): δ = 199.9, 148.6,
21.1 ppm. IR (KBr): ν = 2920, 1595, 1245 cm–1. LRMS (EI, 70 eV):
˜
m/z (%) = 352 (97) [M]+, 245 (32), 202 (27), 135 (100), 77 (31). 147.7, 137.8, 137.4, 136.8, 136.1, 134.8, 133.2, 129.6 (2 C), 129.2,
HRMS (EI) for C25H20O2 [M]+ calcd. 352.1458; found 352.1460.
128.9, 128.3, 128.2, 127.5, 126.6, 104.0, 101.9, 101.3, 21.0 ppm. IR
(KBr): ν = 2918, 1663, 1465, 1248 cm–1. LRMS (EI, 70 eV): m/z
˜
1-[4-(2-p-Tolyl-1-naphthoyl)phenyl]ethanone (16): Following the ge-
neral procedure, the title compound was obtained in 76% yield
(83 mg). Yellow oil. 1H NMR (300 MHz, CDCl3): δ = 8.02 (d, J =
8.8 Hz, 1 H, Ar-H), 7.94 (d, J = 8.4 Hz, 1 H, Ar-H), 7.79 (d, J =
(%) = 366 (100) [M]+, 289 (89), 231 (18), 105 (24), 77 (34). HRMS
(EI) for C25H18O3 [M]+ calcd. 366.1250; found 366.1252.
(6-Fluoro-2-p-tolylnaphthalen-1-yl)(phenyl)methanone (21): Follow-
8.2 Hz, 2 H, Ar-H), 7.71–7.67 (m, 3 H, Ar-H), 7.58–7.45 (m, 3 H, ing the general procedure, the title compound was obtained in 80%
Ar-H), 7.23 (d, J = 8.0 Hz, 2 H, Ar-H), 7.03 (d, J = 7.8 Hz, 2 H,
yield (82 mg). Yellow oil. 1H NMR (300 MHz, CDCl3): δ = 7.93
(d, J = 8.5 Hz, 1 H, Ar-H), 7.71–7.68 (m, 1 H, Ar-H), 7.64–7.51
Ar-H), 2.53 (s, 3 H, -COCH3), 2.24 (s, 3 H, -CH3) ppm. 13C NMR
Eur. J. Org. Chem. 2010, 4211–4217
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
4215

X. Zhao, X.-G. Zhang, R.-Y. Tang, C.-L. Deng, J.-H. Li
FULL PAPER
(m, 4 H, Ar-H), 7.43–7.38 (m, 1 H, Ar-H), 7.31–7.18 (m, 5 H, Ar-
Acknowledgments
H), 7.03 (d, J = 8.4 Hz, 2 H, Ar-H), 2.24 (s, 3 H, -CH3) ppm. 13C
1
NMR (75 MHz, CDCl3): δ = 199.4, 160.6 (d, JC,F = 246.2 Hz),
The authors thank the National Natural Science Foundation of
China (No. 20872112) and the Zhejiang Provincial Natural Science
Foundation of China (No. Y407116) for financial support.
137.7, 137.3, 137.0, 133.4, 133.3, 129.6, 129.3, 129.0, 128.9, 128.7,
128.7, 128.3, 128.1, 128.0, 127.7, 117.4 (2JC,F = 25.1 Hz), 111.3,
(2JC,F = 20.3 Hz), 21.1 ppm. IR (KBr): ν = 2921, 1666, 1241 cm–1.
˜
LRMS (EI, 70 eV): m/z (%) = 340 (100) [M]+, 263 (88), 220 (37),
105 (52), 77 (44). HRMS (EI) for C24H17FO [M]+ calcd. 340.1258;
found 340.1262.
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(6-Fluoro-2-m-tolylnaphthalen-1-yl)(phenyl)methanone (22): Follow-
ing the general procedure, the title compound was obtained in 73%
yield (75 mg). Yellow oil. 1H NMR (300 MHz, CDCl3): δ = 7.95
(d, J = 8.6 Hz, 1 H, Ar-H), 7.76–7.73 (m, 1 H, Ar-H), 7.63–7.54
(m, 4 H, Ar-H), 7.41–7.38 (m, 1 H, Ar-H), 7.28–7.22 (m, 3 H, Ar-
H), 7.16–7.00 (m, 4 H, Ar-H), 2.25 (s, 3 H, -CH3) ppm. 13C NMR
1
(75 MHz, CDCl3): δ = 199.3, 160.6 (d, JC,F = 245.9 Hz), 139.8,
137.8, 137.0, 135.7, 133.5, 133.3, 130.2, 129.5 (2 C), 128.8, 128.7,
2
128.3 (2 C), 128.2, 128.1, 127.7, 126.5, 117.4 (d, JC,F = 25.1 Hz),
2
111.3 (d, JC,F = 20.3 Hz), 21.3 ppm. IR (KBr): ν = 2924, 1663,
˜
1240 cm–1. LRMS (EI, 70 eV): m/z (%) = 340 (100) [M]+, 325 (52),
263 (75), 220 (32), 105 (47). HRMS (EI) for C24H17FO [M]+ calcd.
340.1258; found 340.1262.
[6-Fluoro-2-(4-fluorophenyl)naphthalen-1-yl](phenyl)methanone (23):
Following the general procedure, the title compound was obtained
1
in 61% yield (63 mg). Yellow oil. H NMR (300 MHz, CDCl3): δ
= 7.95 (d, J = 8.5 Hz, 1 H, Ar-H), 7.76–7.71 (m, 1 H, Ar-H), 7.61–
7.54 (m, 4 H, Ar-H), 7.45–7.40 (m, 1 H, Ar-H), 7.32–7.21 (m, 5 H,
Ar-H), 6.95–6.89 (m, 2 H, Ar-H) ppm. 13C NMR (75 MHz,
1
1
CDCl3): δ = 199.2, 162.2 (d, JC,F = 246.1 Hz), 160.7 (d, JC,F
=
246.5 Hz), 137.6, 135.9, 133.6, 131.1, 131.0, 129.5, 128.9, 128.8,
2
128.6, 128.4, 128.2, 128.1, 127.6, 117.6 (d, JC,F = 21.4 Hz), 115.4
2
2
(d, JC,F = 25.2 Hz), 111.3 (d, JC,F = 20.3 Hz) ppm. IR (KBr): ν
˜
= 3060, 1663, 1507, 1224 cm–1. LRMS (EI, 70 eV): m/z (%) = 344
(97) [M]+, 267 (100), 238 (47), 105 (80), 77 (59). HRMS (EI) for
C23H14F2O [M]+ calcd. 344.1007; found 344.1011.
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[2-(4-Chlorophenyl)-6-fluoronaphthalen-1-yl](phenyl)methanone
(24): Following the general procedure, the title compound was ob-
tained in 65% yield (70 mg). Yellow oil. 1H NMR (300 MHz,
CDCl3): δ = 7.99 (d, J = 8.5 Hz, 1 H, Ar-H), 7.74–7.69 (m, 1 H,
Ar-H), 7.61–7.53 (m, 4 H, Ar-H), 7.47–7.41 (m, 1 H, Ar-H), 7.30–
7.18 (m, 7 H, Ar-H) ppm. 13C NMR (75 MHz, CDCl3): δ = 199.1,
1
160.8 (d, JC,F = 246.8 Hz), 138.3, 137.5, 133.73, 133.67, 133.5,
130.7, 129.5, 128.94, 128.87, 128.50, 128.48, 128.42, 128.25, 128.13,
2
2
127.6, 117.7 (d, JC,F = 25.1 Hz), 111.3 (d, JC,F = 20.5 Hz) ppm.
IR (KBr): ν = 3060, 1664, 1497, 1240 cm–1. LRMS (EI, 70 eV): m/z
˜
(%) = 360 (100) [M]+, 283 (69), 220 (46), 105 (98). HRMS (EI) for
C23H14ClFO [M]+ calcd. 360.0712; found 360.0713.
[2-(2-Chlorophenyl)-6-fluoronaphthalen-1-yl](phenyl)methanone
(25): Following the general procedure, the title compound was ob-
tained in 45% yield (49 mg). Yellow solid, m.p. 133.7–137.5 °C. 1H
NMR (300 MHz, CDCl3): δ = 7.94 (d, J = 8.5 Hz, 1 H, Ar-H),
7.78–7.73 (m, 1 H, Ar-H), 7.72–7.54 (m, 4 H, Ar-H), 7.47–7.39 (m,
1 H, Ar-H), 7.28–7.21 (m, 5 H, Ar-H), 7.14–7.08 (m, 2 H, Ar-
1
H) ppm. 13C NMR (75 MHz, CDCl3): δ = 198.6, 160.9 (d, JC,F
=
246.4 Hz), 137.7, 136.9, 134.1, 133.9, 133.8, 133.5, 132.5, 129.5,
129.4, 129.2, 128.7, 128.3, 128.2, 128.0, 127.9, 127.6, 126.3, 117.4
2
2
(d, JC,F = 25.1 Hz), 111.4 (d, JC,F = 24.5 Hz) ppm. IR (KBr): ν
˜
= 3062, 1664, 1238 cm–1. LRMS (EI, 70 eV): m/z (%) = 360 (1)
[M]+, 325 (100), 220 (13), 105 (20), 77 (21). HRMS (EI) for
C23H14ClFO [M]+ calcd. 360.0712; found 360.0713.
Supporting Information (see footnote on the first page of this arti-
cle): NMR spectra (1H and 13C) of compounds 3–12 and 15–25.
4216
www.eurjoc.org
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2010, 4211–4217

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[17] CCDC-775610 (for 8) contains the supplementary crystallo-
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www.ccdc.cam.ac.uk/data_request/cif.
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Received: April 12, 2010
Published Online: June 18, 2010
Eur. J. Org. Chem. 2010, 4211–4217
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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