An Approach to the Synthesis of 1-Propenylnaphthols and 3-Arylnaphtho[2,1-b]furans

Article abstract of DOI:10.1021/acs.joc.6b02902

A simple and efficient strategy for the synthesis of 1-propenylnaphthols from readily accessible 3-arylallylnaphthyl ethers has been developed. By using K₂CO₃ as base and 2-methoxyethanol as solvent, direct access to a wide range of

Full text of DOI:10.1021/acs.joc.6b02902

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Article
An Approach to the Synthesis 1-
Propenylnaphthols and 3-Arylnaphtho[2,1-b]furans
Jin Huang, Wei Wang, Hai-Yu He, Lei Jian, Hai-Yan Fu, Xue-Li Zheng, Hua Chen, and Rui-Xiang Li
J. Org. Chem., Just Accepted Manuscript • DOI: 10.1021/acs.joc.6b02902 • Publication Date (Web): 06 Feb 2017
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An Approach to the Synthesis 1-Propenylnaphthols and
3-Arylnaphtho[2,1-b]furans
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Jin Huang,a Wei Wang, b Hai-Yu He,a Lei Jian,a Hai-Yan Fu,*a Xue-Li Zheng,a Hua Chen,a
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Rui-Xiang Li*a
aKey lab of Green Chemistry and Technology, Ministry of Education; College of Chemistry,
Sichuan University, Chengdu 610064, People’s Republic of China
bState Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China
Medical School, Sichuan University, Chengdu 610064, People’s Republic of China
Abstract: A simple and efficient strategy for the synthesis of 1-propenylnaphthols from readily
accessible 3-arylallylnaphthyl ethers has been developed. By using K2CO3 as base and
2-methoxyethanol as solvent, direct access to a wide range of 1-propenylnaphthols can be
achieved in generally good yield (up to 99 %) with high stereoselectivity towards Z-isomer. The
control experiments indicate that the reaction proceed through a sequential Claisen
rearrangement/isomerization process. Furthermore, starting from the same material, the highly
valuable 3-arylnaphtho[2,1-b]furans can be obtained in N,N-dimethylformamide and in the
presence of Ag2O as the oxidant via a one-pot sequential Claisen rearrangement/isomerization/
cyclization reaction. Mechanistic studies confirm that 1-propenylnaphthols are the key
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intermediates to form the 3-arylnaphtho[2,1-b]furans. In addition, these two operationally
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simple and practical protocols could be scaled up to gram level.
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Keywords: Claisen rearrangement; Isomerization; Cyclization; Alkenylnaphthol;
Naphthofuran.
Introduction
The alkenylnaphthols are important structure unit existing in many biologically active
compounds, showing anti-inflammatory or antiviral activity (Figure 1).1 Moreover, such
compounds are very useful intermediates in organic synthesis because they can be readily
participated in a wide spectrum of reactions by acting on the hydroxyl group and
carbon-carbon double bonds.2 Particularly, they can serve as an important precursor for
preparation naphtho[b]furans (Figure 1).3
Figure 1. Structure of bioactive alkenylnaphthols and naphtho[b]furans.
The most convenient way for preparation of alkenylnaphthols is by Claisen rearrangement
/isomerization of allyl naphthyl ethers.4 However, the major drawback of the reported
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procedure is that it often requires high temperature (ranging from 180 to 240 C) and
expensive isomerization catalysts, such as Rh,4b Ru,4b,4e Ir.4a Moreover, the products were
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usually obtained as a mixture of E- or Z-isomers [Scheme 1, eq.(1)]. Recently, a
hydroarylation reaction of alkynes with naphthol protocol has been developed independently
by Kumar,5 Yadav,6a and Fedushkin,6b by employing an expensive indium salt or gallium
complex [Scheme 1, eq.(2)]. In addition, an example of alkenylation of naphthol by using
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magnesium alkylidene carbenoids under -78 C has also been reported [Scheme 1, eq. (3)].7
However, the forcing reaction condition, poor selectivity, and the expensive catalysts limit the
synthetic utility of these methods. Consequently, the development of an efficient and practical
method for synthesis of alkenylnaphthols is highly desirable.
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Scheme 1. The strategies for the construction of the alkenylnaphthol and naphtho[b]furan
skeleton.
On the other hand, naphtho[2,1-b]furan derivatives are found in a large number of natural
products and synthetic pharmaceuticals.8 A wide variety of synthetic methods have been
established in the literature for synthesis of them.2f,9 The commonly used method is by
cyclization of prefunctionalized naphthol such as 2-alkenylnaphthol, usually promoted either
9c
by employing transition metal catalyst9a,9b,9i or toxic reagents such as I2 and hypervalent
iodine [Scheme 1, eq.(4)].9f In recent years, significant progress has been made in
development of more straightforward methods by transition metal catalyzed coupling reaction
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of simple naphthol and alkynes.2f Very recently, Dong, Zhou, and coworkers have developed
an elegant metal-free approach whereby a direct oxidative coupling of free naphthols with
terminal alkynes could be achieved in the presence of BF3•Et2O [Scheme 1, eq.(5)].9h While
the majority of these methods yielded 2-arylnaphtho[2,1-b]furan as products. In contrast, the
Claisen rearrangement of an allyl or propargyl naphthyl ether followed by intramolecular
cyclization provides 3-arylnaphtho[2,1-b]furan [Scheme 1, eq.(6)].9e We have previously
reported a transition-metal free protocol for synthesis of 3-arylnaphtho[2,1-b]furan starting
from 3-arylallyl bromonaphthyl ethers by employing such a strategy.10 Moreover, we found
that the use of suitable base could lead to formation of alkenylnaphthols as the major products
[Scheme 1, eq. (7)]. Nevertheless, the commercial availability of such special 3-arylallyl
2-bromonaphthyl ether substrates is very limited. In addition, undesired halogen-containing
wastes are generated, which doesn’t meet the requirement of green and atom economic
chemistry. Herein, we demonstrate our efforts in the development of the novel protocols to
synthesize both 1-propenylnaphthols and 3-arylnaphtho[2,1-b]furans from the simple
3-arylallyl naphthyl ether via a Claisen rearrangement, isomerization or cyclization cascade
event [Scheme 1, eq.(8)].
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Results and Discussion
We initiated the investigations by using [[(2E)-3-phenyl-2-propen-1-yl]oxy]naphthalene (1a)
as model substrate, employing the conditions similar to those reported by our group for the
Claisen rearrangement/cyclization of bromonaphthyl 3-phenylallyl ethers.10 Gratifyingly, the
desired transformation proceeded readily under basic condition. In addition, this reaction
performed well in controlling the stereoselectivity, and almost exclusively Z- product 2a was
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obtained, the structure of which was unambiguously assigned based on a single-crystal X-ray
diffraction.10 Screening of bases for the reaction identified K2CO3 was the most effective one
when N,N-dimethylformamide (DMF) was used as solvent (81% yield, Table 1, entry 5).
NaHCO3 and Na2CO3, were also effective, but gave slightly lower yields of the desired
product 2a (62% and 69%; Table 1, entries 3 and 4), while the weaker bases such as NaOAc
and KOAc resulted in further reduced yields (30% and 53%; Table 1, entries 1 and 2).
However, the use of stronger bases, such as K3PO4, NaOH, LiOtBu, NaOtBu, and KOtBu, did
not improve the yield of 2a (48-73% yields; Table 1, entries 6-10). Remarkably, by employing
sodium or potassium carbonate as base, a detectable amount of naphtho[2,1-b]furan 3a was
observed (7% and 6%; Table 1, entries 4 and 5 ).
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Table 1. Effect of bases on this reactiona
Yield (%)b
Entry
Base
2a
3a
1
2
3
4
NaOAc
KOAc
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53
62
69
-
-
NaHCO3
Na2CO3
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K2CO3
K3PO4
NaOH
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73
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-
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LiOtBu
NaOtBu
KOtBu
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aReaction conditions: 1a (0.25 mmol), Base (0.5 mmol), DMF (1 mL), under nitrogen, 120 oC,
20 h. bYields are determined by HPLC. “-” being not detected.
The effect of solvent was then examined by using K2CO3 as the base. The results are
summarized in Table 2. Evidently, the reaction conversion among the tested aprotic solvents
followed the order: toluene < 1,4-dioxane < NMP < DMA < DMF (15-81% yields; Table 2,
entries 1-5), which is basically consistent with their solvent polarity trend. The reactivity
increased in the polar solvent possibly owing to their relatively higher solubility towards the
inorganic base. While for the protic solvents, there seemed no clear correlation between
solvent polarity and conversions. For example, n-butanol and cyclohexanol gave 2a in
comparable yields with DMF (Table 2, entries 6 and 7), but the more polar protic solvents
such as 1,2-propanediol, ethylene glycol led to a significant decrease (Table 2, entries 9 and
10). Notably, the optimal solvent was found to be 2-methoxyethanol affording 2a in 97% yield
(Table 2, entry 8). However, the structurally similar solvent 1,2-dimethoxyethane (DME) only
provided the poor yield (Table 2, entry 11), testifying the positive effect of the –OH group in
2-methoxyethanol. The amount of K2CO3 was also briefly assessed. The best yield of 2a was
observed when 2 equiv of K2CO3 was employed (Table 2, entries 8 vs 13). No desired product
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2a was detected in the absence of base (Table 2, entry 14), showing that the presence of base is
crucial for enabling this reaction. Notably, the reaction gave a significant yield of 3a under
oxygen atmosphere (13%, Table 2, entry 12). Based on these optimization studies, the
following reactions were performed in 2-methoxyethanol at 120 oC in the presence of 2 equiv
of K2CO3.
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Table 2. Effect of solvents on this reactiona
Yield (%)b
Entry
K2CO3
(mmol)
Solvent
2a
3a
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0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
toluene
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1,4-dioxane
NMP
-
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-
4
DMA
-
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DMF
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-
6
n-butanol
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cyclohexanol
2-methoxyethanol
1,2-propanediol
ethylene glycol
DME
-
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3
-
9
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11
12c
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14
31
28
87
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-
-
2-methoxyethanol
2-methoxyethanol
2-methoxyethanol
13
-
0.25
0
-
-
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aReaction conditions: 1a (0.25 mmol), under nitrogen, Solvent (1 mL), 120 oC, 20 h. Yields
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are determined by HPLC. cUnder oxygen atmosphere.
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With the optimized conditions in hand, we subsequently tested the scope of this reaction.
First, the effect of varying the nature of functional groups on the 3-phenyl moiety was
investigated. As shown in Scheme 2, both the electron-donating methyl group (2b, 2h) and
the electron-withdrawing chloro, fluoro and trifluoromethyl groups (2c-g, 2i-j) were well
tolerated. The transformation proceeded quite smoothly and afforded the desired
1-propenylnaphthol derivatives in moderate to good yields (31-90%). Para-substituted
phenyl derivatives bearing electron donating methyl group afforded the products in higher
yield than those bearing electron-withdrawing groups (Scheme 2, 2b vs 2c-e). Substituents at
either the meta- or sterically demanding ortho-position led to moderate to excellent yields of
products. Interestingly, the more sterically hindered ortho-substituted aryls afforded the
corresponding products in much higher yields than those with meta- or para- substituents
(2h-j vs 2b-g). Unexpectedly, for substrate 1k bearing a 2-CF3 group, a double bond
isomerization occurred to give vinyl ether 1k' in 23% yield, and no desired product was
observed due to intramolecular [1,3]-type H-shift.2c,11 Notably, the isomer1-naphthyl ether
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Scheme 2. Scope of the reaction for the synthesis of 1-propenylnaphthols. Reaction conditions:
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1 (0.25 mmol), K2CO3 (0.5 mmol), 2-methoxyethanol (1 mL), under nitrogen, 120 C, 20 h.
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Yields of isolated products.
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a1a' was used. c1w was used.
bIn the glove box.
(1a') could also take place this rearrangement/isomerization procedure, giving the product 2a'
in 35% yield as a mixture of Z- and E- isomer (about 6.6:1).
To further evaluate the scope of the reaction, the present protocol was then extended to the
substrates having the naphthalene with different substitution patterns. All of the tested
substrates also worked efficiently and gave moderate to excellent yields of the desired
products 2l-2v (35-99%). Again, a good functional group tolerance was observed. It was
noteworthy that substrate 1l containing a 7-Br group at the naphthyl moiety, the corresponding
naphthol 2l was obtained in up to 99% yield. Whereas when Br atom was at the C-6 position
the yield decreased to 70% (2o). The remaining bromide functional group can serve as a
versatile handle for further manipulation. However, substitution at the 2-, 3- or 4-position of
3-phenyl moiety with electron-withdrawing fluoro or chloro groups remarkably reduced the
yields (2m, 2n, 2p). Importantly, substrates bearing pharmaceutically relevant quinoline
rings12 could also react, resulting in the 6-quinolinols 2r-2v with up to 99% yields.
Unfortunately, the rearrangement reaction was completely supressed when
2-(allyloxy)naphthalene 1w was employed. It is noteworthy that the highly valuable
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naphtho[b]furans were generated as coproducts in a number of instances (3a, 3d, 3g, 3m, 3n,
3o, 3p, 3s, 3v) in 7-33% yields, it was possible that the trace amount of oxygen in the solvent
might facilitate the formation of 3. As expected, the corresponding naphthol products were
obviously increased for the substrates 1g, 1m, and 1p when the reaction was carried out in the
glove box (86-89%).
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The observation of the coproduct naphtho[2,1-b]furan promoted us to develop an efficient
way
for
preparing
naphthofuran
derivatives
using
a
one-pot
Claisen
rearrangement/isomerization/cyclization cascade event. We were pleased to find that 1a can be
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easily transformed into the corresponding naphtho[2,1-b]furan 3a at 130 C in 85% isolated
yield in the presence of Ag2O merely by switching the solvent from 2-methoxyethanol to
DMF (for the detailed condition screening, see Table 1 in the Supporting Information). The
substrate scope for this transformation was also investigated. As shown in Scheme 3, the
reactions of 3-arylallylnaphthyl ethers, bearing various substituents, such as halogen, alkyl or
alkoxyl group, all efficiently provided the corresponding naphthofurans in moderate to good
yields. It should be noted that the substrate bearing Br atom on naphthalene exhibited the
reactivity similar to that observed in naphthols system, and the substrate containing Br at C-7
position gave the higher yield than that at C-6 position (3l vs 3o). In addition, the quinolinyl
allyl ethers 1r and 1t could also be smoothly transformed into the quinoline[b]furan 3r and 3t
in high yields by using more Ag2O to accelerate the reaction. The isomer 1-naphthyl ether (1a')
was also compatible with this novel one-pot protocol and formed the naphtho[1,2-b]furan 3a',
albeit in lower yield (20%). The relatively lower reactivity of 1a compared with 1a' was well
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in agreement with the literture.13 Whereas no desired cyclization product was detected for the
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substrate 1w.
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Scheme 3. Scope of the reaction for the synthesis of 3-aryl naphtho[b]furans. Reaction
conditions: 1 (0.25 mmol), K2CO3 (0.5 mmol), DMF (1 mL), Ag2O (0.25 mmol), under
nitrogen, Yields of isolated products. a0.5 mmol of Ag2O.
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Collectively, 3-arylallyl naphthyl ethers were found to be a useful substrate capable of being
transformed into both alkenylnaphthols and naphtho[2,1-b]furans under different conditions. It
is worthy mentioned that no transition metal catalyst was employed in the former reaction and
Z-isomer product was nearly exclusively formed under the established conditions. This was far
superior to the previously reported methods, which required noble metal catalysts and gave
product in a mixture of E- and Z-isomers.4 In the latter case, 3-aryl substituted
naphtho[2,1-b]furans were effectively formed, which is otherwise difficult to obtain.9e We
subsequently tested the scalability of these two transformations by using 4 mmol 1a. The
corresponding products 2a and naphtho[b]furan 3a could be obtained in 73% and 70% isolated
yields [Scheme 4, eq.(1) and (2)], demonstrating that the reaction was amenable to scale-up
although with slight loss of yield.
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Scheme 4. Scale up and synthetic application.
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To insight into the origin that underlie the reactions, several experiments to elucidate the
mechanism were performed (Scheme 5). It was found that 1a failed to give any of the desired
product 2a in absence of a base, instead the ortho-Claisen rearrangement product 4a was
formed in 90% yield [Scheme 5, eq.(1)]. But with the addition of K2CO3 it can be easily
transformed into 2a in high yield [Scheme 5, eq.(2)]. This implies that base was absolutely
essential for the double bond isomerization process. We then treated 2a and 4a with Ag2O
respectively to investigate which one is the intermediate for the route to naphtho[2,1-b]furans.
The desired product 3a could be formed in 93% yield from 2a [Scheme 5, eq.(2)]. In contrast,
only trace amounts of 3a was obtained from 4a. While upon exposure to Ag2O and K2CO3, 4a
could also be successfully cyclized via a dehydrogenation process to produce
naphtho[2,1-b]furans in 87 % yield [Scheme 5, eq.(1)]. These results clearly indicated that 2a
was an important intermediate for the formation of 3a. But the cyclization of 2a did not occur
in the absence of Ag2O.
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Scheme 5. Mechanistic investigations.
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Scheme 6. Proposed mechanism.
On the basis of above results and literature reports,14-16 a reasonable mechanism proposed
for above two transformations is summarized in Scheme 6. First, allyl naphthyl ether 1a
readily undergoes a Claisen rearrangement to give an ortho benzodienone A which usually
enolizes into naphthol 4a.14 And then the 4a transformed to phenoxide B in the presence of
base. Subsequently, B undergoes a base promoted synergistic hydrogen transfer to afford 2a.15
Almost exclusively Z-isomer was given due to the electrostatic attraction in C.15 Finally, in the
presence of Ag2O, 2a is easily dehydrogenated and cyclized into naphtho[2,1-b]furan 3a. In
order to explore the cyclization mechanism of 2a, the introduction of TEMPO as a trapping
agent resulted in the yield of 3a decrease from 93% to 75%. When the amount of TEMPO was
further increased, the yield of 3a dropped to 61% (for the details see Table 2 in the Supporting
Information). Obviously, the reactivity was partly inhibited by TEMPO. According to the
reported results,16 if a radical reaction occurs in intramolecular or the radical reaction rate is
quickly, the radical trapping agent is difficult to trap it. The possibility for involvement of
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intramolecular radical pathway still can not be rule out. So we speculated that naphthoxide ion
of 2a is oxidized by Ag2O to form naphthoxide radical, which subsequently undergoes the
oxidative cyclization to give 3a.
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Conclusions
We have developed simple and efficient methods to construct various 1-propenylnaphthols
and 3-arylnaphtho[2,1-b]furans from readily accessible 3-arylallylnaphthyl ethers in a
practical and atom economical way. In the former case, the reaction，involving the Claisen
rearrangement followed by a base-induced double bond isomerization, stereoselectively
produces (Z)-1-aryl-1-propenylnaphthols. More importantly, such an alkenylnaphthols can
easily undergo the oxidative cyclization to form 3-arylnaphtho[2,1-b]furans in the presence of
Ag2O, thus enabling us to develop a one-pot sequential Claisen rearrangement/isomerization/
cyclization reactions for synthesis of naphtho[2,1-b]furans. Compared with the previous
approaches, the present novel methodologies comprise the advantages of simple reaction
system, operational ease, high stereoselectivity, and broad applicability, and should be an
attractive choice for the synthesis of 1-propenylnaphthol and 3-arylnaphtho[2,1-b]furans
derivatives.
Experimental section
The synthesis of substrates 1a, 1a', 1l, 1o, 1q, 1r, 1u, 1w:
The starting naphthol (10 mmol) and K2CO3 (30 mmol) were dissolved in acetone (30 mL).
Cinnamyl bromide (8 mmol) was added by syringe and the reaction was heated to 60 °C
overnight. After cooling, the mixture was diluted with ethyl acetate and water. The organic
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layer was washed with brine, dried with anhydrous MgSO4, and concentrated under vacuum.
The residue was purified by silica gel chromatography using petroleum ether/ethyl acetate
(10:1) as eluent.
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The synthesis of substrates 1b-1k, 1m, 1n, 1p, 1s, 1t, 1v:
For the synthesis of 1b, 4-methylcinnamic acid S-1b (2.5 g) and p-toluenesulfonic acid (1.0 g)
were dissolved in EtOH (20 mL). The resulting mixture was refluxed for 3 h, and then treated
with petroleum ether (50 mL). The organic layer was washed with water (20 mL) and 10%
Na2CO3 solution (20 mL), dried with anhydrous MgSO4, and evaporated under reduced
pressure to obtain compound S-2b (2.0 g) as a colorless liquid.
DIBAL-H (1.0 M, 25 ml) was slowly added to a stirred solution of ester S-2b (1.9 g, 10
mmol) in THF (35 ml) at −78 °C. The reaction mixture was stirred for 1 h at −78 °C and for
another 1 h at room temperature. After completion, the reaction mixture was poured into cold
diluted HCl (0.5 N), and extracted with ethyl acetate. The organic layer was dried over
anhydrous MgSO4, and evaporated under reduced pressure to obtain compound S-3b (1.5 g)
as a colorless liquid.
To a stirred solution of S-3b (5 mmol), 2-naphthol (6 mmol), and triphenylphosphane (1.7 g,
6.5 mmol) in THF (30 ml) under nitrogen atmosphere was added diethylazodicarboxylate
(DEAD, 1.2 mL) drop-wise at 0 °C. The mixture was further stirred at room temperature for
20 h. The solvent was evaporated under reduced pressure on a rotary evaporator to give a
viscous residue. The residue was purified by silica gel column chromatography to give 1b
(0.6 g) as a white solid.
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Typical procedure for the synthesis 2a: A mixture of 1a (0.25 mmol), K2CO3 (0.5 mmol) in
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nitrogen. At the end of the reaction, water (3 mL) was added into the mixture and
subsequently the mixture was extracted with ethyl acetate (3 × 5 mL). The combined organic
extract was washed with brine (3 × 5 mL), dried with anhydrous MgSO4, and concentrated
under vacuum. The residue was purified by silica gel chromatography using petroleum
ether-ethyl acetate (20:1) as eluent to give the pure product 2a (58 mg, 90 %).
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Typical procedure for the synthesis 3a: A mixture of 1a (0.25 mmol), K2CO3 (0.5 mmol),
Ag2O (0.25 mmol) in DMF (1 mL) was stirred in a dried Schlenk tube for 20 h at 130 oC. At
the end of the reaction, water (3 mL) was added into the mixture and subsequently the
mixture was extracted with ethyl acetate (3 × 5 mL). The combined organic extract was
washed with brine (3 × 5 mL), dried with anhydrous MgSO4, and concentrated under vacuum.
The residue was purified by silica gel chromatography using petroleum ether as eluent to give
the pure product 3a (55 mg, 85 %).
2-[[(2E)-3-phenyl-2-propen-1-yl]oxy]Naphthalene (1a). 78% (1.6 g) as a white solid; mp:
110-111 oC. 1H NMR (400 MHz, CDCl3) δ 7.81 – 7.71 (m, 3H), 7.48 – 7.41 (m, 3H), 7.38 –
7.31 (m, 3H), 7.29 – 7.25 (m, 1H), 7.24 – 7.19 (m, 2H), 6.80 (d, J = 16.0 Hz, 1H), 6.49 (dtd,
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J = 16.0, 5.8, 2.3 Hz, 1H), 4.82 (dd, J = 5.8, 1.3 Hz, 2H). C NMR (101 MHz, CDCl3) δ
155.5, 135.4, 133.5, 132.1, 128.4, 128.0, 127.6, 126.9, 126.6, 125.8, 125.6, 125.3, 123.3,
122.7, 118.0, 106.0, 67.6. HRMS(ESI): Calcd for C19H15O [M-H]- 259.1123, found 259.1104.
Spectral data obtained were in agreement with those reported in the literature.14b
2-[[(2E)-3-(4-methylphenyl)-2-propen-1-yl]oxy]Naphthalene (1b). 85% (1.2 g) as a
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white solid; mp: 133-134 oC. 1H NMR (400 MHz, CDCl3) δ 7.79 – 7.70 (m, 3H), 7.46 – 7.41
(m, 1H), 7.36 – 7.30 (m, 3H), 7.23 – 7.18 (m, 2H), 7.14 (d, J = 7.9 Hz, 2H), 6.76 (d, J = 16.0
Hz, 1H), 6.44 (dt, J = 16.0, 5.9 Hz, 1H), 4.80 (dd, J = 5.9, 1.4 Hz, 2H), 2.34 (s, 3H). 13C
NMR (101 MHz, CDCl3) δ 156.6, 137.8, 134.5, 133.7, 133.2, 129.5, 129.3, 129.0, 127.7,
126.8, 126.5, 126.4, 123.7, 123.2, 119.0, 107.1, 68.8, 21.2. HRMS(ESI): Calcd for C20H17O
[M-H]- 273.1279, found 273.1274.
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2-[[(2E)-3-(4-chlorophenyl)-2-propen-1-yl]oxy]Naphthalene (1c). 80% (1.2 g) as a white
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solid; mp: 132-134 C. H NMR (400 MHz, CDCl3) δ 7.81 – 7.72 (m, 3H), 7.47 – 7.42 (m,
1H), 7.39 – 7.28 (m, 5H), 7.23 – 7.18 (m, 2H), 6.75 (d, J = 16.0 Hz, 1H), 6.47 (dt, J = 16.0,
5.7 Hz, 1H), 4.81 (dd, J = 5.7, 1.2 Hz,2H). 13C NMR (101 MHz, CDCl3) δ 156.5, 135.0,
134.5, 133.6, 131.8, 129.5, 129.1, 128.8, 127.8, 127.7, 126.8, 126.4, 125.0, 123.8, 118.9,
107.0, 68.4. HRMS(ESI): Calcd for C19H14ClO [M-H]- 293.0733, found 293.0719.
2-[[(2E)-3-(4-fluorophenyl)-2-propen-1-yl]oxy]Naphthalene (1d). 78% (1.1 g) as a white
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solid; mp: 124-125 C. H NMR (400 MHz, CDCl3) δ 7.82 – 7.71 (m, 3H), 7.47 – 7.31 (m,
4H), 7.24 – 7.18 (m, 2H), 7.02 (t, J = 8.5 Hz, 2H), 6.75 (d, J = 16.0 Hz, 1H), 6.40 (dt, J =
16.0, 5.8 Hz, 1H), 4.80 (dd, J = 5.8, 1.3 Hz, 2H). 13C NMR (101 MHz, CDCl3) δ 162.7,
160.3, 155.5, 133.5, 131.6, 131.0, 128.5, 128.1, 127.2, 127.1, 126.7, 125.8, 125.4, 123.1,
122.7, 117.9, 114.6, 114.4, 106.1, 67.5. HRMS(ESI): Calcd for C19H14FO [M-H]- 277.1029,
found 277.1013.
2-[[(2E)-3-(4-trifluoromethylphenyl)-2-propen-1-yl]oxy]Naphthalene (1e). 83% (1.4 g) as
a white solid; mp: 170-172 oC. 1H NMR (400 MHz, CDCl3) δ 7.80 – 7.72 (m, 3H), 7.59 (d, J
= 8.3 Hz, 2H), 7.52 (d, J = 8.2 Hz, 2H), 7.47 – 7.42 (m, 1H), 7.38 – 7.32 (m, 1H), 7.24 – 7.18
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(m, 2H), 6.83 (d, J = 16.0 Hz, 1H), 6.58 (dt, J = 16.0, 5.5 Hz, 1H), 4.85 (dd, J = 5.4, 1.2 Hz,
2H). 13C NMR (101 MHz, CDCl3) δ 156.4, 139.9, 134.5, 131.3, 130.7, 129.9, 129.6, 129.1,
127.7, 127.1, 126.8, 126.7, 126.5, 125.7, 125.6 (2C), 125.5, 123.8, 118.9, 107.1, 68.2.
HRMS(ESI): Calcd for C20H14F3O [M-H]- 327.0997, found 327.0983.
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2-[[(2E)-3-(3-chlorophenyl)-2-propen-1-yl]oxy]Naphthalene (1f). 75% (1.1 g) as a white
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solid; mp: 104-106 C. H NMR (400 MHz, CDCl3) δ 7.81 – 7.70 (m, 3H), 7.48 – 7.40 (m,
2H), 7.38 – 7.32 (m, 1H), 7.31 – 7.27 (m, 2H), 7.24 – 7.18 (m, 3H), 6.74 (d, J = 16.0 Hz, 1H),
6.49 (dt, J = 16.0, 5.6 Hz, 1H), 4.82 (d, J = 5.5 Hz, 2H). 13C NMR (101 MHz, CDCl3) δ
156.4, 138.3, 134.6, 134.5, 131.5, 129.9, 129.6, 129.1, 127.9, 127.7, 126.8, 126.5 (2C), 125.9,
124.8, 123.8, 118.9, 107.0, 68.3. HRMS(ESI): Calcd for C19H14ClO [M-H]- 293.0733, found
293.0715.
2-[[(2E)-3-(3-fluorophenyl)-2-propen-1-yl]oxy]Naphthalene (1g). 76% (1.1 g) as a white
solid; mp: 78-80 oC. 1H NMR (400 MHz, CDCl3) δ 7.81 – 7.71 (m, 3H), 7.48 – 7.41 (m, 1H),
7.38 – 7.31 (m, 1H), 7.31 – 7.26 (m, 1H), 7.23 – 7.17 (m, 3H), 7.13 (d, J = 10.0 Hz, 1H), 6.96
(td, J = 8.4, 1.3 Hz, 1H), 6.76 (d, J = 16.0 Hz, 1H), 6.49 (dt, J = 16.0, 5.6 Hz, 1H), 4.82 (d, J
= 5.6 Hz, 2H). 13C NMR (101 MHz, CDCl3) δ 163.2, 160.8, 155.4, 137.7, 133.4, 130.7 (2C),
129.0, 128.9, 128.4, 128.0, 126.6, 125.7, 125.3, 124.7, 122.7, 121.4 (2C), 117.8, 113.7, 113.5,
112.0, 111.8, 105.9, 67.2. HRMS(ESI): Calcd for C19H14FO [M-H]- 277.1029, found
277.1010.
2-[[(2E)-3-(2-methylphenyl)-2-propen-1-yl]oxy]Naphthalene (1h). 62% (0.8 g) as a white
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solid; mp: 94 C. H NMR (400 MHz, CDCl3) δ 7.81 – 7.71 (m, 3H), 7.52 – 7.48 (m, 1H),
7.47 – 7.42 (m, 1H), 7.37 – 7.32 (m, 1H), 7.23 – 7.20 (m, 2H), 7.19 – 7.14 (m, 3H), 7.02 (d, J
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= 15.8 Hz, 1H), 6.37 (dt, J = 15.8, 5.8 Hz, 1H), 4.84 (dd, J = 5.8, 1.4 Hz, 2H), 2.36 (s, 3H).
13C NMR (101 MHz, CDCl3) δ 155.5, 134.6 (2C), 133.5, 130.1, 129.3, 128.4, 128.0, 126.8,
126.6, 125.7, 125.3, 125.1, 124.8, 124.6, 122.6, 118.0, 106.1, 67.9, 18.8. HRMS(ESI): Calcd
for C20H17O [M-H]- 273.1279, found 273.1273.
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2-[[(2E)-3-(2-chlorophenyl)-2-propen-1-yl]oxy]Naphthalene (1i). 64% (0.9 g) as a white
solid; mp: 84-85 oC. 1H NMR (400 MHz, CDCl3) δ 7.80 – 7.73 (m, 3H), 7.59 (dd, J = 7.5, 1.9
Hz, 1H), 7.47 – 7.42 (m, 1H), 7.39 – 7.31 (m, 2H), 7.25 – 7.17 (m, 5H), 6.47 (dt, J = 16.0, 5.8
Hz, 1H), 4.86 (dd, J = 5.8, 1.5 Hz, 2H). 13C NMR (101 MHz, CDCl3) δ 155.4, 133.6, 133.5,
132.2, 128.7, 128.5, 128.4, 128.0, 127.9, 126.6, 126.3, 126.0, 125.9, 125.8, 125.4, 122.7,
118.0, 106.0, 67.6. HRMS(ESI): Calcd for C19H14ClO [M-H]- 293.0733, found 293.0723.
2-[[(2E)-3-(2-fluorophenyl)-2-propen-1-yl]oxy]Naphthalene (1j). 70% (1.0 g) as a white
solid; mp: 97-98 oC. 1H NMR (400 MHz, CDCl3) δ 7.80 – 7.72 (m, 3H), 7.47 (dtd, J = 15.1,
8.1, 1.2 Hz, 2H), 7.37 – 7.31 (m, 1H), 7.24 – 7.19 (m, 3H), 7.11 (td, J = 7.6, 0.9 Hz, 1H),
7.05 (ddd, J = 10.7, 8.2, 1.0 Hz, 1H), 6.96 (d, J = 16.2 Hz, 1H), 6.58 (dt, J = 16.2, 5.7 Hz,
1H), 4.84 (dd, J = 5.7, 1.4 Hz, 2H). 13C NMR (101 MHz, CDCl3) δ 161.6, 159.1, 156.5, 134.5,
129.5, 129.3, 129.2, 129.1, 127.7, 127.1, 127.0, 126.8, 126.4, 125.6 (2C), 124.3, 124.2 (2C),
124.1, 123.7, 119.0, 115.9, 115.7, 107.1, 68.7. HRMS(ESI): Calcd for C19H14FO [M-H]-
277.1029, found 277.1015.
2-[[(2E)-3-(2-trifluoromethylphenyl)-2-propen-1-yl]oxy]Naphthalene (1k). 73% (1.2 g) as
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a white solid; mp: 102-103 C. H NMR (400 MHz, CDCl3) δ 7.81 – 7.70 (m, 3H), 7.68 –
7.60 (m, 2H), 7.53 – 7.40 (m, 2H), 7.37 – 7.31 (m, 2H), 7.24 – 7.14 (m, 3H), 6.44 (dt, J =
15.8, 5.7 Hz, 1H), 4.84 (dd, J = 5.7, 1.3 Hz, 2H). 13C NMR (101 MHz, CDCl3) δ 156.5, 135.7,
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134.6, 132.0, 129.6, 129.2, 129.1, 127.8, 127.7 (2C), 127.5, 126.9, 126.5, 126.0, 125.9 (2C),
125.8 (2C), 123.9, 123.1, 119.1, 107.2, 68.6. HRMS(ESI): Calcd for C20H14F3O [M-H]-
327.0997, found 327.0977.
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1-[[(2E)-3-phenyl-2-propen-1-yl]oxy]Naphthalene (1a'). 75% (1.5 g) as a white solid; mp:
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80-82 C. H NMR (600 MHz, CDCl3) δ 8.36 – 8.32 (m, 1H), 7.83 – 7.78 (m, 1H), 7.52 –
7.46 (m, 2H), 7.46 – 7.43 (m, 3H), 7.39 – 7.33 (m, 3H), 7.27 (t, J = 7.3 Hz, 1H), 6.88 (d, J =
7.6 Hz, 1H), 6.83 (d, J = 16.0 Hz, 1H), 6.54 (dt, J = 16.0, 5.7 Hz, 1H), 4.89 (d, J = 5.6 Hz,
2H). Spectral data obtained were in agreement with those reported in the literature.14b
7-bromo-2-[[(2E)-3-phenyl-2-propen-1-yl]oxy]Naphthalene (1l). 74% (2 g) as a white
solid; mp: 130 oC. 1H NMR (400 MHz, CDCl3) δ 7.89 (d, J = 1.7 Hz, 1H), 7.72 (d, J = 9.0 Hz,
1H), 7.63 (d, J = 8.7 Hz, 1H), 7.45 – 7.39 (m, 3H), 7.37 – 7.31 (m, 2H), 7.28 (d, J = 7.5 Hz,
1H), 7.21 (dd, J = 9.0, 2.4 Hz, 1H), 7.09 (d, J = 2.4 Hz, 1H), 6.79 (d, J = 16.0 Hz, 1H), 6.47
(dt, J = 16.0, 5.8 Hz, 1H), 4.80 (d, J = 5.8 Hz, 2H). 13C NMR (101 MHz, CDCl3) δ 157.3,
136.3, 135.8, 133.4, 129.5, 129.3, 128.8, 128.6, 128.0, 127.4, 127.0, 126.6, 124.0, 120.6,
119.4, 106.2, 68.7. HRMS(ESI): Calcd for C19H14BrO [M-H]- 337.0228, found 337.0209.
7-bromo-2-[[(2E)-3-(2-chlorophenyl)-2-propen-1-yl]oxy]Naphthalene (1m). 63% (1.2 g)
as a white solid; mp: 98-99 oC. 1H NMR (400 MHz, CDCl3) δ 7.89 (d, J = 1.8 Hz, 1H), 7.72
(d, J = 9.0 Hz, 1H), 7.63 (d, J = 8.7 Hz, 1H), 7.58 (dd, J = 7.4, 2.0 Hz, 1H), 7.39 (ddd, J = 9.3,
8.2, 1.9 Hz, 2H), 7.25 – 7.17 (m, 4H), 7.10 (d, J = 2.4 Hz, 1H), 6.45 (dt, J = 16.0, 5.8 Hz, 1H),
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4.84 (dd, J = 5.8, 1.5 Hz, 2H). C NMR (101 MHz, CDCl3) δ 156.2, 134.7, 133.5, 132.2,
128.7, 128.6, 128.5, 128.3, 128.0, 127.7, 126.4, 126.0 (2C), 125.9, 125.1, 119.6, 118.4, 105.2,
67.6. HRMS(ESI): Calcd for C19H13BrClO [M-H]- 370.9838, found 370.9815.
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7-bromo-2-[[(2E)-3-(3-chlorophenyl)-2-propen-1-yl]oxy]Naphthalene (1n). 67% (1.2 g)
as a white solid; mp: 123 oC. 1H NMR (400 MHz, CDCl3) δ 7.89 (d, J = 1.7 Hz, 1H), 7.73 (d,
J = 9.0 Hz, 1H), 7.63 (d, J = 8.7 Hz, 1H), 7.46 – 7.39 (m, 2H), 7.33 – 7.26 (m, 2H), 7.25 –
7.19 (m, 2H), 7.08 (d, J = 2.4 Hz, 1H), 6.73 (d, J = 16.0 Hz, 1H), 6.48 (dt, J = 16.0, 5.6 Hz,
1H), 4.81 (dd, J = 5.6, 1.4 Hz, 2H). 13C NMR (101 MHz, CDCl3) δ 156.1, 137.1, 134.6,
133.5, 130.6, 128.8, 128.4, 128.2, 127.7, 126.8, 126.3, 126.0, 125.4, 124.5, 123.7, 119.5,
118.2, 105.0, 67.2. HRMS(ESI): Calcd for C19H13BrClO [M-H]- 370.9838, found 370.9823.
6-bromo-2-[[(2E)-3-phenyl-2-propen-1-yl]oxy]Naphthalene (1o). 71% (1.9 g) as a white
solid; mp: 148 oC. 1H NMR (400 MHz, CDCl3) δ 7.92 (d, J = 1.8 Hz, 1H), 7.66 (d, J = 9.0 Hz,
1H), 7.60 (d, J = 8.8 Hz, 1H), 7.50 (dd, J = 8.7, 2.0 Hz, 1H), 7.45 – 7.41 (m, 2H), 7.37 – 7.31
(m, 2H), 7.29 – 7.26 (m, 1H), 7.22 (dd, J = 9.0, 2.5 Hz, 1H), 7.16 (d, J = 2.4 Hz, 1H), 6.79 (d,
J = 16.0 Hz, 1H), 6.47 (dt, J = 16.0, 5.8 Hz, 1H), 4.80 (dd, J = 5.8, 1.4 Hz, 2H). 13C NMR
(101 MHz, CDCl3) δ 155.8, 135.3, 132.3, 132.0, 129.1, 128.6 (2C), 127.6 (2C), 127.4, 127.0,
125.6, 123.0, 119.0, 116.1, 106.0, 67.7. HRMS(ESI): Calcd for C19H14BrO [M-H]- 337.0228.
found 337.0217.
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6-bromo-2-[[(2E)-3-(4-fluorophenyl)-2-propen-1-yl]oxy]Naphthalene (1p). 68% (1.2 g) as
a white solid; mp: 134-136 oC. 1H NMR (400 MHz, CDCl3) δ 7.92 (d, J = 1.4 Hz, 1H), 7.66
(d, J = 9.0 Hz, 1H), 7.59 (d, J = 8.8 Hz, 1H), 7.50 (dd, J = 8.7, 1.9 Hz, 1H), 7.42 – 7.36 (m,
2H), 7.26 – 7.19 (m, 1H), 7.14 (d, J = 2.3 Hz, 1H), 7.02 (t, J = 8.6 Hz, 2H), 6.74 (d, J = 16.0
Hz, 1H), 6.38 (dt, J = 16.0, 5.8 Hz, 1H), 4.78 (d, J = 5.8 Hz, 2H). 13C NMR (101 MHz,
CDCl3) δ 163.8, 161.3, 156.8, 133.0, 132.5 (2C), 132.2, 130.1, 129.7, 128.6, 128.4, 128.2,
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128.1, 123.7 (2C), 120.0, 117.2, 115.7, 115.5, 107.0, 68.6. HRMS(ESI): Calcd for
C19H13BrFO [M-H]- 355.0134, found 355.0117.
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6-methoxy-2-[[(2E)-3-phenyl-2-propen-1-yl]oxy]Naphthalene (1q). 71% (1.6 g) as a white
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solid; mp: 156 C. H NMR (400 MHz, CDCl3) δ 7.65 (t, J = 8.9 Hz, 2H), 7.45 – 7.41 (m,
2H), 7.36 - 7.30 (m, 2H), 7.29 – 7.26 (m, 1H), 7.21 – 7.16 (m, 2H), 7.15 – 7.10 (m, 2H), 6.78
(d, J = 16.0 Hz, 1H), 6.48 (dt, J = 16.0, 5.8 Hz, 1H), 4.79 (dd, J = 5.8, 1.4 Hz, 2H), 3.90 (s,
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3H). C NMR (101 MHz, CDCl3) δ 156.2, 155.1, 136.5, 133.1, 129.9, 129.7, 128.6, 128.2,
127.9, 126.6, 124.5, 119.2, 119.0, 109.7, 107.5, 106.1, 68.8, 55.3. HRMS(ESI): Calcd for
C20H17O2 [M-H]- 289.1229, found 289.1207.
7-[[(2E)-3-phenyl-2-propen-1-yl]oxy] quinoline (1r). 65% (1.4 g) as a white solid; mp:
80-81 oC. 1H NMR (400 MHz, CDCl3) δ 8.77 (dd, J = 4.2, 1.5 Hz, 1H), 8.10 – 8.01 (m, 2H),
7.47 – 7.41 (m, 3H), 7.39 – 7.31 (m, 3H), 7.30 – 7.24 (m, 1H), 7.14 (d, J = 2.7 Hz, 1H), 6.80
(d, J = 16.0 Hz, 1H), 6.47 (dt, J = 16.0, 5.8 Hz, 1H), 4.83 (d, J = 5.8 Hz, 2H). 13C NMR (101
MHz, CDCl3) δ 155.8, 146.9, 143.3, 135.3, 134.1, 132.5, 129.9, 128.3, 127.7, 127.1, 125.7,
122.9, 121.7, 120.4, 105.5, 68.0. HRMS(ESI): Calcd for C18H14NO [M-H]- 260.1075, found
260.1067.
7-[[(2E)-3-(4-methylphenyl)phenyl-2-propen-1-yl]oxy] quinoline (1s). 68% (0.9 g) as a
white solid; mp: 93-95 oC . 1H NMR (400 MHz, CDCl3) δ 8.78 (dd, J = 4.2, 1.4 Hz, 1H), 8.09
– 8.01 (m, 2H), 7.44 (dd, J = 9.2, 2.8 Hz, 1H), 7.39 – 7.31 (m, 3H), 7.18 – 7.12 (m, 3H), 6.76
(d, J = 16.0 Hz, 1H), 6.43 (dt, J = 15.9, 5.9 Hz, 1H), 4.81 (dd, J = 5.9, 1.2 Hz, 2H), 2.35 (s,
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3H). C NMR (101 MHz, CDCl3) δ 155.7, 146.9, 143.3, 137.0, 134.0, 132.5, 132.4, 129.8,
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128.3 (2C), 125.5, 121.7, 121.6, 120.3, 105.3, 68.0, 20.2. HRMS(ESI): Calcd for C19H16NO
[M-H]- 274.1232, found 274.1226.
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7-[[(2E)-3-(2-methylphenyl)phenyl-2-propen-1-yl]oxy] quinoline (1t). 76% (1.0 g) as a
white solid; mp: 83 oC. 1H NMR (400 MHz, CDCl3) δ 8.79 (dd, J = 4.3, 1.6 Hz, 1H), 8.12 –
8.01 (m, 2H), 7.53 – 7.49 (m, 1H), 7.46 (dd, J = 9.2, 2.7 Hz, 1H), 7.37 (dd, J = 8.3, 4.2 Hz,
1H), 7.22 – 7.14 (m, 4H), 7.02 (d, J = 15.8 Hz, 1H), 6.37 (dt, J = 15.8, 5.8 Hz, 1H), 4.85 (d, J
= 5.8 Hz, 2H), 2.36 (s, 3H). 13C NMR (101 MHz, CDCl3) δ 155.7, 147.0, 143.3, 134.6, 134.4,
133.9, 130.4, 129.9, 129.3, 128.2, 126.9, 125.2, 124.8, 124.1, 121.6, 120.4, 105.4, 68.1, 18.8.
HRMS(ESI): Calcd for C19H16NO [M-H]- 274.1232, found 274.1223.
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2-methyl -7-[[(2E)-3-phenyl-2-propen-1-yl]oxy] quinoline (1u). 74% (1.6 g) as a white
solid; mp: 98-99 oC. 1H NMR (400 MHz, CDCl3) δ 7.99 – 7.92 (m, 2H), 7.46 – 7.38 (m, 3H),
7.37 – 7.31 (m, 2H), 7.29 – 7.26 (m, 1H), 7.26 – 7.22 (m, 1H), 7.11 (d, J = 2.8 Hz, 1H), 6.79
(d, J = 16.0 Hz, 1H), 6.47 (dt, J = 16.0, 5.8 Hz, 1H), 4.81 (dd, J = 5.8, 1.2 Hz, 2H), 2.72 (s,
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3H). C NMR (101 MHz, CDCl3) δ 155.4, 155.1, 142.7, 135.2, 134.1, 132.2, 128.9, 127.5,
126.9, 126.2, 125.5, 122.9, 121.2, 121.1, 105.5, 67.8, 23.9. HRMS(ESI): Calcd for C19H18NO
[M+H]+ 276.1388, found 276.1371.
2-methyl-7-[[(2E)-3-(4-methylphenyl)phenyl-2-propen-1-yl]oxy] quinoline (1v). 76% (1.1
g) as a white solid; mp: 125-126 oC. 1H NMR (400 MHz, CDCl3) δ 7.94 (d, J = 8.8 Hz, 2H),
7.40 (dd, J = 9.1, 2.7 Hz, 1H), 7.33 (d, J = 8.0 Hz, 2H), 7.28 – 7.22 (m, 1H), 7.17 – 7.09 (m,
3H), 6.75 (d, J = 16.0 Hz, 1H), 6.42 (dt, J = 15.9, 5.9 Hz, 1H), 4.79 (d, J = 5.8 Hz, 2H), 2.71
(s, 3H), 2.34 (s, 3H). 13C NMR (101 MHz, CDCl3) δ 156.4, 156.2, 143.8, 137.9, 135.2, 133.5,
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133.4, 130.0, 129.3, 127.3, 126.5, 122.9, 122.3, 106.5, 69.1, 25.0, 21.3. HRMS(ESI): Calcd
for C20H20NO [M+H]+ 290.1545, found 290.1529.
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2-(allyloxy)naphthalene (1w). 75% (1.1 g) as a colorless liquid; 1H NMR (400 MHz, CDCl3)
δ 7.76 – 7.65 (m, 3H), 7.44 – 7.38 (m, 1H), 7.34 – 7.27 (m, 1H), 7.18 – 7.13 (m, 1H), 7.10 (d,
J = 1.5 Hz, 1H), 6.15 – 6.03 (m, 1H), 5.48 – 5.40 (m, 1H), 5.29 (dd, J = 10.5, 1.4 Hz, 1H),
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4.60 (dt, J = 5.3, 1.3 Hz, 2H). C NMR (101 MHz, CDCl3) δ 156.6, 134.6, 133.3, 129.5,
129.1, 127.8, 126.9, 126.5, 123.8, 119.1, 117.9, 107.1, 68.9. Spectral data obtained were in
agreement with those reported in the literature.17
1-(1-phenyl-1-propen-1-yl)-2-Naphthol (2a). 90% (59 mg) as a white solid; mp: 108-109
oC. 1H NMR (400 MHz, CDCl3) δ 7.83 – 7.77 (m, 2H), 7.52 – 7.46 (m, 1H), 7.34 – 7.28 (m,
3H), 7.27 – 7.18 (m, 5H), 6.80 (q, J = 6.9 Hz, 1H), 5.37 (s, 1H), 1.62 (d, J = 6.9 Hz, 3H). 13C
NMR (101 MHz, CDCl3) δ 150.3, 139.8, 134.4, 132.7, 129.7, 129.6, 129.2, 128.7, 128.2,
127.5, 126.6, 125.9, 124.6, 123.3, 117.6, 117.1, 15.5. MS (ESI): Calcd for C19H15O [M-H]-
259.1123, found 259.11. Spectral data obtained were in agreement with those reported in the
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1-[1-(4-methylphenyl)-1-propen-1-yl]-2-Naphthol (2b). 68% (46 mg) as a yellow oil; H
NMR (400 MHz, CDCl3) δ 7.84 – 7.76 (m, 2H), 7.53 – 7.46 (m, 1H), 7.34 – 7.31 (m, 1H),
7.30 – 7.28 (m, 1H), 7.27 – 7.23 (m, 1H), 7.16 (d, J = 8.2 Hz, 2H), 7.04 (d, J = 8.2 Hz, 2H),
6.76 (q, J = 6.9 Hz, 1H), 5.38 (s, 1H), 2.29 (s, 3H), 1.61 (d, J = 6.9 Hz, 3H). 13C NMR (101
MHz, CDCl3) δ 150.2, 137.4, 136.9, 134.2, 132.7, 129.5, 129.4, 129.1, 128.6, 128.1, 126.6,
125.8, 124.7, 123.3, 117.8, 117.1, 21.1, 15.4. HRMS (ESI): Calcd for C20H17O [M-H]-
273.1279, found 273.1278.
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1-[1-(4-chlorophenyl)-1-propen-1-yl]-2-Naphthol (2c). 31% (23 mg) as a yellow oil; H
NMR (400 MHz, CDCl3) δ 7.85 – 7.77 (m, 2H), 7.46 – 7.41 (m, 1H), 7.35 – 7.29 (m, 2H),
7.27 (d, J = 8.9 Hz, 1H), 7.19 (s, 4H), 6.80 (q, J = 6.9 Hz, 1H), 5.31 (s, 1H), 1.63 (d, J = 6.9
Hz, 3H). 13C NMR (101 MHz, CDCl3) δ 134.7, 122.7, 118.0, 117.8, 117.0, 114.6, 114.3,
113.7, 113.3, 112.7, 111.7, 111.2, 108.9, 107.9, 101.6, 101.5, 14.2. HRMS(ESI): Calcd for
C19H14ClO [M-H]- 293.0733, found 293.0728.
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1-[1-(4-fluorophenyl)-1-propen-1-yl]-2-Naphthol (2d). 47% (33 mg) as a yellow solid; mp:
89 oC. 1H NMR (400 MHz, CDCl3) δ 7.85 – 7.78 (m, 2H), 7.48 – 7.43 (m, 1H), 7.35 – 7.29
(m, 2H), 7.29 – 7.26 (m, 1H), 7.25 – 7.21 (m, 2H), 6.96 – 6.89 (m, 2H), 6.74 (q, J = 6.9 Hz,
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1H), 5.35 (s, 1H), 1.62 (d, J = 6.9 Hz, 3H). C NMR (101 MHz, CDCl3) δ 163.5, 161.1,
150.2, 135.9, 135.8, 133.4, 132.5, 129.7, 129.4, 129.2, 128.2, 127.6, 127.5, 126.7, 124.5,
123.4, 117.3, 117.1, 115.6, 115.4, 15.5. HRMS(ESI): Calcd for C19H14FO [M-H]- 277.1029,
found 277.1033.
1-[1-(4-trifluoromethylphenyl)-1-propen-1-yl]-2-Naphthol (2e). 41% (33 mg) as a white
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solid; mp: 146-148 C. H NMR (400 MHz, CDCl3) δ 7.86 – 7.80 (m, 2H), 7.52 – 7.47 (m,
2H), 7.45 – 7.40 (m, 1H), 7.37 (d, J = 8.6 Hz, 2H), 7.34 – 7.31 (m, 2H), 7.28 (d, J = 8.9 Hz,
1H), 6.92 (q, J = 6.9 Hz, 1H), 1.68 (d, J = 6.9 Hz, 3H). 13C NMR (101 MHz, CDCl3) δ 150.3,
143.3, 133.7, 132.5, 132.1, 130.0, 129.6, 129.2, 128.3, 126.9, 126.2, 125.7 (2C), 125.6 (2C),
124.3, 123.6, 122.8, 117.2, 116.8, 15.7. HRMS(ESI): Calcd for C20H14F3O [M-H]- 327.0997,
found 327.1018.
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NMR (400 MHz, CDCl3) δ 7.85 – 7.79 (m, 2H), 7.48 – 7.42 (m, 1H), 7.37 – 7.30 (m, 3H),
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1.6 Hz, 1H), 6.83 (q, J = 6.9 Hz, 1H), 5.30 (s, 1H), 1.64 (d, J = 6.9 Hz, 3H). C NMR (101
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MHz, CDCl3) δ 150.3, 141.8, 134.7, 133.5, 132.5, 131.1, 129.9 (2C), 129.2, 128.3, 127.6,
126.8, 125.9, 124.4, 124.3, 123.5, 117.2, 116.9, 15.6. HRMS(ESI): Calcd for C19H14ClO
[M-H]- 293.0733, found 293.0738.
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NMR (400 MHz, CDCl3) δ 7.87 – 7.78 (m, 2H), 7.50 – 7.42 (m, 1H), 7.36 – 7.31 (m, 2H),
7.28 (d, J = 9.0 Hz, 1H), 7.20 (td, J = 8.0, 6.1 Hz, 1H), 7.04 (d, J = 7.9 Hz, 1H), 7.01 – 6.95
(m, 1H), 6.91 (td, J = 8.3, 2.5 Hz, 1H), 6.84 (q, J = 6.9 Hz, 1H), 5.30 (s, 1H), 1.64 (d, J = 6.9
Hz, 3H). 13C NMR (101 MHz, CDCl3) δ 163.4, 161.0, 149.3, 141.2 (2C), 132.6, 131.5, 129.9,
129.1 (2C), 128.9, 128.2, 127.3, 125.8, 123.4, 122.5, 120.6 (2C), 116.2, 116.0, 113.5, 113.3,
111.9, 111.7, 14.6. HRMS(ESI): Calcd for C19H14FO [M-H]- 277.1029, found 277.1022.
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NMR (400 MHz, CDCl3) δ 7.79 – 7.74 (m, 2H), 7.54 (dd, J = 8.2, 0.8 Hz, 1H), 7.34 – 7.26
(m, 2H), 7.23 (d, J = 8.9 Hz, 1H), 7.20 – 7.12 (m, 3H), 7.11 – 7.08 (m, 1H), 6.37 (q, J = 6.9
Hz, 1H), 5.58 (s, 1H), 2.31 (s, 3H), 1.70 (d, J = 6.9 Hz, 3H). 13C NMR (101 MHz, CDCl3) δ
150.3, 141.1, 135.3, 135.0, 133.5, 132.6, 131.4, 129.7, 129.3, 129.2, 128.2, 127.3, 126.5,
126.1, 124.8, 123.2, 118.7, 117.1, 20.9, 15.7. HRMS(ESI): Calcd for C20H17O [M-H]-
273.1279, found 273.1271.
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NMR (400 MHz, CDCl3) δ 7.70 (d, J = 9.1 Hz, 2H), 7.64 (d, J = 8.4 Hz, 1H), 7.31 (t, J = 7.5
Hz, 2H), 7.26 – 7.20 (m, 1H), 7.16 (d, J = 8.9 Hz, 1H), 7.10 – 6.98 (m, 3H), 6.54 (q, J = 6.8
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