A catalyst-free benzylic C-H bond olefination of azaarenes for direct mannich-like reactions

Article abstract of DOI:10.1021/jo2008934

A highly efficient synthesis of trans-alkenylazaarene under catalyst-free conditions was developed via the addition of methylazaarenes to N-sulfonyl aldimines and a subsequent C-N elimination in situ. A one-pot procedure for this addition-elimination was also developed. The reaction could tolerate a broad substrate scope and give the corresponding alkenylazaarenes in high yields.

Full text of DOI:10.1021/jo2008934

NOTE
pubs.acs.org/joc
A Catalyst-Free Benzylic CÀH Bond Olefination of Azaarenes for Direct
Mannich-like Reactions
Yizhe Yan, Kun Xu, Yang Fang, and Zhiyong Wang*
Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Soft Matter Chemistry, and Department of
Chemistry, University of Science and Technology of China, Hefei, 230026, P. R. China
S Supporting Information
b
ABSTRACT: A highly efficient synthesis of trans-alkenylazaar-
ene under catalyst-free conditions was developed via the
addition of methylazaarenes to N-sulfonyl aldimines and a
subsequent CÀN elimination in situ. A one-pot procedure for
this additionÀelimination was also developed. The reaction
could tolerate a broad substrate scope and give the correspond-
ing alkenylazaarenes in high yields.
ransition-metal-catalyzed sp3 CÀH bond functionalizations
have emerged as important methods for CÀC bond forma-
to generate the corresponding aldehyde (Table 1, entries 16
and 17). In addition, reducing the amount of 2-methylquinoline
incurred a decrease in the reaction yields (Table 1, entries 18
and 19). Therefore, the optimal conditions are those described
in entry 4.
T
tion in synthetic organic chemistry.1,2 Although many excellent
results have been reported, the functionalization of a methyl
group directly attached to an aromatic ring remains limited.3
Recently, Huang and Rueping reported the palladium or Lewis
acid catalyzed benzylic addition of 2-methylazaarenes to N-
sulfonyl aldimines (Scheme 1A).4 Concurrently, Kanai and
Matsunaga reported a Lewis acid catalyzed benzylic CÀH bond
functionalization of alkyl-substituted azaarenes.5 In their report, a
mechanism via premetalation of the 2-methyl group was pro-
posed. In our study about the addition of 2-methylazaarenes to
N-sulfonyl aldimines, we found that no addition product 4 was
observed, but elimination products 3 were obtained in the
absence of metal (Scheme 1B).6
Under the optimized reaction conditions, the scope of the
reaction substrates was investigated. As shown in Table 2, various
N-tosyl aldimines 2aÀ2u were employed in this reaction. No
electronic effect was observed when different substituents were
located on the phenyl ring of aromatic aldimines. Both electron-
withdrawing and electron-donating substituents were tolerated
in this reaction (Table 2, entries 5, 7, 11À14). There seems to be
some steric effect in this reaction because R1 bearing a substituent
at ortho-position gave a lower yield in comparison with the R1
bearing a substituent at para-position (Table 2, entries 2, 4À10).
The reactions of ring-fused, heterocyclic, and styryl aldimines
also gave the corresponding products in satisfactory yields
(Table 2, entries 15À17 and 19), except for 2-pyridyl aldimine
(Table 2, entry 18). To our delight, aliphatic tosyl aldimines can
also be the substrates in this reaction despite slightly lower yields
(Table 2, entries 20 and 21). It was noted that in every case an
excellent stereoselctivity can be obtained.
2-Alkenylazaarenes 3 can be used as antagonist, antiprolifera-
tive, antiviral, and antimicrobial agents because of their important
biological activities.7 Although the aldol reactions of 2-methyl
azaarenes were directly used to synthesize alkenylazaarenes in the
presence of strong acid or base,8 only low E/Z selectivity was
obtained. Herein, we report a highly efficient and stereoselective
synthesis of alkenylazaarenes through the addition of methyla-
zaarenes to N-sulfonyl aldimines and a subsequent CÀN elim-
ination in situ without any metal catalyst or other additives.
Moreover, a one-pot procedure based on p-toluenesulfonamide
was developed to simplify this tedious additionÀelimination.
Initially, the reaction of 2-methylquinoline (1a) with N-tosyl
aldimine (2a) was chosen as a model reaction to optimize
reaction conditions. Solvent polarity had no effect on the E/Z
ratio (Table 1, entries 1À4). However, the less polar solvent
(toluene) gave the highest yield (Table 1, entry 4). The optimal
temperature was found to be 120 °C (Table 1, entries 4À6).
Subsequently, when various Lewis acids were added, the reac-
tions resulted in lower yields and poor selectivities of E/Z
(Table 1, entries 7À15). When a base was added, no desired
product was observed because N-tosyl aldimine was hydrolyzed
Subsequently, various R2 substitutents on N-sulfonyl aldi-
mines were also examined when R1 was fixed as a phenyl group.
When different sulfonyl groups were used as the N-protecting
groups, the reaction can give desired product 3aa in 84À98%
yield (Table 3, entries 1À8). It was noteworthy that aldimine
bearing a m-nitrobenzenesulfonyl group as an N-protecting
group resulted in the highest yield (Table 3, entry 2). These
results indicated that the stronger the electron-withdrawing
capability of R2, the higher the reactivity or the eletrophilicity
of sp2 carbon of aldimine. Subsequently, only a 10% yield of
3aa was obtained with benzyl (Bn) as an N-protecting group
Received: May 6, 2011
Published: July 14, 2011
r
2011 American Chemical Society
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dx.doi.org/10.1021/jo2008934 J. Org. Chem. 2011, 76, 6849–6855
|

The Journal of Organic Chemistry
NOTE
Scheme 1. Benzylic CÀH Bond Transformations
Table 1. Optimization of Reaction Conditionsa
Table 2. Substrate Scope of Various N-Tosyl Aldiminesa
R1
product
yield (%)b
E/Zc
entry solvent
additive
temp (°C) yield (%)b
E/Zc
entry
1
2
THF
DMF
DMSO
tol.
70
120
120
120
140
80
36
66
72
92
92
57
54
48
48
69
80
79
90
27
52
0
>99:1
>99:1
>99:1
>99:1
>99:1
>99:1
95:5
1
Ph
3aa
3ab
3ac
3ad
3ae
3af
92
90(92d)
>99:1
>99:1
>99:1
>99:1
>99:1
>99:1
>99:1
>99:1
>99:1
>99:1
95:5
2
4-Cl-Ph
3
3
3-Cl-Ph
90
4
4
2-Cl-Ph
86
5
4-CF3-Ph
2-CF3-Ph
4-NO2-Ph
2-NO2-Ph
4-OMe-Ph
2-OMe-Ph
2,4-di-OMe-Ph
4-Me-Ph
3-Me-Ph
2-Me-Ph
1-naphthyl
2-furyl
94(96d)
80(85d)
94
5
tol.
6
tol.
6
7
tol.
Cu(OAc)2
120
120
120
120
120
120
120
120
120
120
120
120
120
7
3ag
3ah
3ai
8
tol.
CuCl2
87:13
80:20
70:30
30:70
>99:1
>99:1
83:17
90:10
8
90
9
tol.
CuBr2
9
87
76(80d)
10
tol.
Cu(OTf)2
CuBr2 + Cu(OTf)2
CuBr
10
11
12
13
14
15
16
17
18
19
20
21
3aj
11d tol.
3ak
3al
96
12
13
14
15
16
17
18e
19f
tol.
tol.
tol.
tol.
tol.
tol.
tol.
tol.
97
>99:1
>99:1
>99:1
>99:1
>99:1
99:1
Cul
3am
3an
3ao
3ap
3aq
3ar
3as
3at
96
FeCl3
97
ZnCl2
91
79(84d)
70(85d)
tracee
90
Cs2CO3
tBuOK
0
2-thienyl
2-pyridyl
PhCHdCH
cyclohexyl
i-C4H9
86
>99:1
>99:1
90
93:7
99:1
a Reaction conditions: 1a (0.6 mmol), 2a (0.3 mmol), and additive (0.1
equiv) in solvent (0.5 mL) were refluxed for 12 h under N2. b Isolated
yields. c Determined by GC-MS on the basis of peak areas. d CuBr2
71
3au
78
>99:1
a Reaction conditions: 1a (0.6 mmol) and 2 (0.3 mmol) in toluene
(0.5 mL) were refluxed at 120 °C for 12 h under N2. b Isolated yields.
c Determined by 1H NMR on the basis of peak areas. d The system was
heated in mesitylene (0.5 mL) at 140 °C. e Unknown complex mixture.
e
(5 mol %) and Cu(OTf)2 (5 mol %) were added in a 1:1 ratio. 1a
(0.3 mmol) was used. f 1a (0.45 mmol) was used.
(Table 3, entry 9). In addition, when phenyl and butylcarbonyl
(Boc) were employed as N-protecting groups, no product was
obtained (Table 3, entries 10 and 11).
Next, the generality of methylazaarenes was investigated in
this reaction. When methylazaarenes (1bÀ1i and 1m) were
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The Journal of Organic Chemistry
NOTE
Table 3. Substrate Scope of Aldimines with Different
Table 4. Substrate Scope of Various Methylazaarenesa
N-Protecting Groupsa
entry
R2
yield (%)b
E/Zc
1
o-toluenesulfonyl
m-nitrobenzenesulfonyl
p-methoxybenzenesulfonyl
benzenesulfonyl
2-mesitylenesulfonyl
2-naphthalenesulfonyl
methanesulfonyl
1-hexadecanesulfonyl
Bn
92
98
88
90
86
89
87
84
10
0
>99:1
>99:1
>99:1
>99:1
>99:1
>99:1
>99:1
>99:1
90:10
2
3
4
5
6
7
8
9
10
11
Ph
Boc
0
a Reaction conditions: 1a (0.6 mmol) and 2 (0.3 mmol) in toluene
(0.5 mL) were refluxed at 120 °C for 12 h under N2. b Isolated yields.
c Determined by 1H NMR on the basis of peak areas.
employed in the reaction, the corresponding products (3ba-3ia
and 3ma) were obtained in 77À90% yield with high stereo-
selectivities (Table 4, entries 1À8 and 12). However, when
1jÀ1l were used as the substrates, only addition products (4ja-
4la) were obtained (Table 4, entries 9À11). In addition, 2,6-
lutidine (1o) also gave the desired product 3oa in 35% yield,
while 2-methylpyridine (1n) did not give any product (Table 4,
entries 13À14). This can be perhaps ascribed to the electronic
effect of the methyl group on the pyridyl ring.
In order to improve atom economy and enhance the reaction
efficiency, we developed a one-pot procedure for this reaction.
When the reaction mixture of 2-methylquinoline, benzaldehyde,
and p-toluenesulfonamide with a ratio of 1:1:1 was heated
either under nitrogen atmosphere or open to air for 12 h, the
product 3aa can be obtained with 93 and 83% isolated yield
respectively (Table 5, entries 1 and 3). With this procedure, the
tedious isolation of N-tosyl aldimines is avoided. The yield was
not increased by increasing the amount of 2-methylquinoline
(Table 5, entry 2). Reducing the amount of p-toluenesulfona-
mide to 0.5 equiv incurred a lower reaction yield of 86%
(Table 5, entry 4). Further reducing the amount of p-toluene-
sulfonamide to 0.2 equiv, the reaction yield was slightly
decreased (Table 5, entry 5). The reaction hardly proceeded
in the absence of p-toluenesulfonamide (Table 5, entry 6). It
was noted that sulfonamide possibly plays the role of a
catalyst in this condensation of aldehydes. Moreover, other
aldehydes and azaarenes can also give the olefination products
with moderate to good yield under these one-pot conditions
(Table 5, entries 7À17) .
a Reaction conditions: 1 (0.6 mmol) and 2a (0.3 mmol) in toluene
(0.5 mL) were refluxed at 120 °C for 12 h under N2. b Isolated yields.
c Determined by 1H NMR on the basis of peak areas. d dr = 1.8:1.
On the basis of the above experimental results, a plausible
reaction pathway is proposed in Scheme 3. First, N-tosyl
aldimine (2a) was formed from benzaldehyde and p-toluenesul-
fonamide in situ. Subsequently, the enamine intermediate 5,
which was generated via the requisite disruption of aromaticity
of 1a, cooperated with 2a to form the cyclic transition state 6.
Then intermediate 4aa was generated via a hydrogen transfer.
Finally, the stable trans-2-styrylquinoline (3aa) was obtained
through the elimination of 4aa in situ (Scheme 3), regenerating
p-toluenesulfonamide.
In conclusion, we have developed a highly efficient synthesis of
trans-alkenylazaarenes under catalyst-free conditions. The one-
pot procedure realizes successfully the condensation of alde-
hydes and methylazaarenes with the use of an organocatalyst,
To get insight into the mechanism of this reaction, several
control experiments were performed. The intermediate 4aa
could be synthesized according to the literature and then
converted to CÀC cleavage product 1a and CÀN cleavage
product 3aa. In addition, 4ja could also give similar products
in mesitylene at a higher temperature (Scheme 2). This indicates
that 4 should be the intermediate of reaction, and the addition
step may be reversible.
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dx.doi.org/10.1021/jo2008934 |J. Org. Chem. 2011, 76, 6849–6855

The Journal of Organic Chemistry
NOTE
Table 5. One-Pot Synthesis of 3a
(3.42 g, 20 mmol), and Si(OEt)4 (4.7 mL, 21 mmol) were placed in a
flask and heated at 120 °C for 12 h . After cooling, the mixture was
crystallized with ethyl acetate and petroleum ether. The resulting solid
was collected by filtration and then dried in a vacuum, giving 2a as a
white solid (3 g, 58% yield).
General Procedure for the Synthesis of Methylazaarenes.
Synthesis of 1b. The mixture of o-aminobenzophenone (394 mg,
2 mmol) and acetone (0.5 mL) in 20% KOH ethanol solution
(10 mL) was refluxed overnight at 80 °C. Then the reaction mixture
was quenched with hydrochloric acid (1 M) and extracted three times
with EtOAc (3 Â 20 mL). The combined organic layers were washed
with brine once and dried over Na2SO4. The organic phase was
concentrated in a vacuum and purified by chromatographic column
over silica gel, giving 2-methyl-4-phenylquinoline (1b) as a light
yellow solid.
entry
R
R1
product
yield (%)b
E/Zc
1
H
H
H
H
H
H
H
H
H
H
H
H
H
Ph
Ph
Ph
Ph
Ph
Ph
3aa
3aa
3aa
3aa
3aa
3aa
3ab
3ag
3ai
93
>99:1
>99:1
>99:1
>99:1
>99:1
2d
3e
4f
5g
6h
7
93
83
86
85
n.d.
4-Cl-Ph
4-NO2-Ph
4-OMe-Ph
4-Me-Ph
2-pyridyl
cyclohexyl
i-C4H9
Ph
95(90g)
90(84)
94(87)
98(90)
81(75)
50(45)
60(50)
90(83)
92(85)
94(86)
92(87)
>99:1
>99:1
>99:1
>99:1
>99:1
>99:1
>99:1
>99:1
>99:1
>99:1
>99:1
Synthesis of 1c.10 The mixture of o-aminobenzophenone (394 mg,
2 mmol), acetylacetone (240 mg, 2.4 mmol), and a grain of I2 in EtOH
(5 mL) was stirred overnight at room temperature. Then the mixture
was quenched with water (15 mL) and extracted with EtOAc (3 Â
20 mL). The organic phase was dried over Na2SO4 and purified by
column chromatography on silica gel, giving 2-methyl-3-acetyl-4-phe-
nylquinoline (1c) as a white solid.
8
9
10
11
12
13
14
15
16
17
3al
3ar
3at
3au
3da
3ea
3ga
3ha
Synthesis of 1d-1j.11 Aniline (2 mmol) was added into a solution of
phosphotungstic acid (2 mmol) in water (10 mL). To this was added
crotonaldehyde (3 mmol) in toluene (15 mL), and the mixture was
heated at 100 °C for 6 h. After cooling to room temperature, the mixture
was basified by sodium hydroxide solution and extracted three times
with EtOAc (3 Â 25 mL). The combined organic layers were dried over
Na2SO4, concentrated, and purified by column chromatography on
silica gel.
6-OMe
6-Me
6-Br
Ph
Ph
6-Cl
Ph
a Reaction conditions: 1 (0.3 mmol), aldehyde (0.3 mmol), and p-
toluenesulfonamide (0.3 mmol) in toluene (0.5 mL) were refluxed at
120 °C for 12 h under N2. b Isolated yields. c Determined by 1H NMR on
the basis of peak areas. d 2 equiv of 1a was used. e Under air. f 0.5 equiv of
p-toluenesulfonamide was used. g 0.2 equiv of p-toluenesulfonamide
was used. h In the absence of p-toluenesulfonamide.
Synthesis of 1k.12 A solution of Sulfo-mix (5.85 g), FeSO4 7H2O
3
(140 mg), H3BO3 (240 mg), water (5 mL), and 1-naphthylamine
(572 mg, 4 mmol) was warmed to 110 °C, and crotonaldehyde (350 mg,
5 mmol) was added dropwise over 30 min. The reaction mixture was
heated at 130 °C for 5 h. The cooled solution was basified with aqueous
20% NaOH and extracted with CHCl3 (3 Â 20 mL). The combined
organic layers were washed with brine and dried over Na2SO4. The
organic phase was concentrated in a vacuum and purified by chromato-
graphic column over silica gel, giving 2-methylbenzo[h]quinoline (1k)
as a yellow solid.
Scheme 2. Control Experiments
Synthesis of the Intermediate 4aa.4 Under N2, Pd(OAc)2 (6.8 mg,
5 mol %), 1,10-phenanthroline (5.4 mg, 5 mol %), and dry CH2Cl2 (2 mL)
were added to a tube. The mixture was kept stirring at room temperature for
0.5 h. After evaporating CH2Cl2, the mixture of 1a (1.5 mmol) and 2a
(0.6 mmol) in dry THF (3 mL) was heated at 120 °C for 24 h. After the
completion of the reaction, the solvent was removed under reduced
pressure and the residue was purified by flash column chromatography
on silica gel, giving 4aa as a white solid (145 mg, 60% yield).
Characterization Data for the Products. (E)-2-Styrylquino-
line (3aa).13 White solid (E:Z > 99:1, 92% yield): mp 98À100 °C; 1H
NMR (300 MHz, CDCl3) δ 8.14À8.07 (m, 2H), 7.78 (d, J = 8.1 Hz,
1H), 7.74À7.63 (m, 5H), 7.52À7.30 (m, 5H); 13C NMR (75 MHz,
CDCl3) δ 156.0, 148.3, 136.6, 136.4, 134.5, 129.8, 129.3, 129.1, 128.8,
128.7, 127.6, 127.4, 126.2, 119.3. HRMS calcd for C17H13N: 231.1048.
Found: 231.1045.
tosylamine. Further investigations of the mechanism and the
application of the reaction are currently underway in our
laboratory.
’ EXPERIMENTAL SECTION
General Procedure for the Synthesis of Alkenylazaarene.
A solution of 1a (81 μL, 0.6 mmol) and 2a (77.7 mg, 0.3 mmol) in
toluene (0.5 mL) was refluxed at 120 °C for 12 h in a reaction tube under
N2. After the mixture was cooled to room temperature, the solvent was
removed under reduced pressure. Then the concentrate was purified
by column chromatography on silica gel, affording 3aa as a white solid
(64 mg, 92% yield).
(E)-2-(4-Chlorostyryl)quinoline (3ab).14 White solid (E:Z > 99:1,
90% yield): mp 143À145 °C; 1H NMR (300 MHz, CDCl3) δ 8.14 (d,
J = 8.4 Hz, 1H), 8.09 (d, J = 8.4 Hz, 1H), 7.79 (d, J = 8.1 Hz, 1H),
7.75À7.62 (m, 3H), 7.59À7.48 (m, 3H), 7.41À7.35 (m, 3H); 13C NMR
(75 MHz, CDCl3) δ 155.6, 148.3, 136.5, 135.1, 134.4, 133.1, 129.9,
129.5, 129.3, 129.1, 128.5, 127.6, 127.5, 126.4, 119.4. HRMS calcd for
C17H12ClN: 265.0658. Found: 265.0660.
General Procedure for the Synthesis of N-Sulfonyl
(E)-2-(3-Chlorostyryl)quinoline (3ac).6 White solid (E:Z > 99:1,
Aldimines.9 Benzaldehyde (2.12 g, 20 mmol), p-toluenesulfonamide
90% yield): mp 97À99 °C; H NMR (300 MHz, CDCl3) δ 8.15
1
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The Journal of Organic Chemistry
NOTE
Scheme 3. Plausible Reaction Pathway
(d, J = 8.4 Hz, 1H), 8.10 (d, J = 8.7 Hz, 1H), 7.79 (d, J = 8.1 Hz, 1H),
7.75À7.62 (m, 4H), 7.54À7.49 (m, 2H), 7.44À7.27 (m, 3H); 13C
NMR (75 MHz, CDCl3) δ 155.4, 148.3, 138.5, 136.5, 134.8, 132.9,
131.0, 130.3, 130.1, 129.9, 129.3, 128.5, 127.6, 127.2, 126.5, 125.5,
119.5. HRMS calcd for C17H12ClN: 265.0658. Found: 265.0655.
(E)-2-(2-Chlorostyryl)quinoline (3ad).15 Light yellow solid (E:Z >
(d, J = 16.8 Hz, 1H), 7.79À7.67 (m, 4H), 7.52À7.46 (m, 2H),
7.32À7.25 (m, 1H), 7.03À6.92 (m, 2H), 3.93 (s, 3H); 13C NMR (75
MHz, CDCl3) δ 157.5, 156.8, 148.2, 136.3, 129.9, 129.7, 129.54, 129.5,
129.2, 127.5, 127.3, 126.1, 125.5, 120.9, 119.1, 111.1, 55.6. HRMS calcd
for C18H15NO: 261.1154. Found: 261.1156.
(E)-2-(2,4-Dimethoxystyryl)quinoline (3ak). Bright yellow oil (E:Z =
95:5, 96% yield): 1H NMR (300 MHz, CDCl3) δ 8.11À8.07 (m, 2H),
7.93 (d, J = 16.8 Hz, 1H), 7.82À7.63 (m, 4H), 7.50À7.26 (m, 2H),
7.32À7.25 (m, 1H), 6.58À6.48 (m, 2H), 3.91 (s, 3H), 3.85 (s, 3H), 3.81
(s, 0.13H), 3.79 (s, 0.13H); 13C NMR (75 MHz, CDCl3) δ 161.4, 158.7,
157.1, 148.1, 136.1, 129.55, 129.5, 129.4, 128.8, 128.2, 127.5, 127.0,
126.3, 125.8, 118.8, 118.5, 105.2, 98.4, 55.5, 55.4. HRMS calcd for
C19H17NO2: 291.1259. Found: 291.1255.
1
99:1, 86% yield): mp 78À80 °C; H NMR (300 MHz, CDCl3) δ
8.16À8.00 (m, 3H), 7.84À7.68 (m, 4H), 7.53À7.39 (m, 3H),
7.33À7.21 (m, 2H); 13C NMR (75 MHz, CDCl3) δ 155.7, 148.2,
136.5, 134.6, 134.1, 131.7, 130.3, 130.0, 129.8, 129.5, 129.3, 127.6, 127.5,
127.1, 127.0, 127.0, 119.0. HRMS calcd for C17H12ClN: 265.0658.
Found: 265.0659.
(E)-2-(4-(Trifluoromethyl)styryl)quinoline (3ae). White solid (E:Z >
99:1, 94% yield): mp 124À126 °C; 1H NMR (300 MHz, CDCl3) δ 8.17
(d, J = 8.7 Hz, 1H), 8.11 (d, J = 8.4 Hz, 1H), 7.81 (d, J = 8.1 Hz, 1H),
7.76À7.63 (m, 7H), 7.56À7.45 (m, 2H); 13C NMR (75 MHz, CDCl3)
δ 155.2, 148.3, 140.0, 136.5, 132.6, 131.3, 130.3, 130.0, 129.3, 127.6,
127.3, 126.6, 126.0, 125.8, 125.7, 119.5. HRMS calcd for C18H12F3N:
299.0922. Found: 299.0925.
(E)-2-(4-Methylstyryl)quinoline (3al).6 White solid (E:Z > 99:1, 97%
yield): mp 140À142 °C; 1H NMR (300 MHz, CDCl3) δ 8.14À8.07 (m,
2H), 7.78 (d, J = 8.1 Hz, 1H), 7.73À7.63 (m, 3H), 7.56À7.46 (m, 3H),
7.38 (d, J = 16.5 Hz, 1H), 7.26À7.19 (m, 2H), 2.38 (s, 3H); 13C NMR
(75 MHz, CDCl3) δ 156.2, 148.3, 138.8, 136.3, 134.5, 133.8, 131.0,
129.7, 129.6, 129.2, 128.0, 127.5, 127.3, 126.1, 119.2, 21.4. HRMS calcd
for C18H15N: 245.1204. Found: 245.1208.
(E)-2-(3-Methylstyryl)quinoline (3am). White solid (E:Z > 99:1, 96%
yield): mp 71À73 °C; 1H NMR (300 MHz, CDCl3) δ 8.12À8.06 (m,
2H), 7.77 (d, J = 8.1 Hz, 1H), 7.73À7.62 (m, 3H), 7.51À7.37 (m, 4H),
7.32À7.24 (m, 1H), 7.03À6.92 (d, J = 7.2 Hz, 1H), 2.39 (s, 3H); 13C
NMR (75 MHz, CDCl3) δ 156.1, 148.3, 138.4, 136.5, 136.3, 134.6,
129.7, 129.5, 129.2, 128.9, 128.7, 128.0, 127.5, 127.4, 126.1, 124.5, 119.2,
21.5. HRMS calcd for C18H15N: 245.1204. Found: 245.1205.
(E)-2-(2-Methylstyryl)quinoline (3an). Colorless oil (E:Z > 99:1,
97% yield): 1H NMR (300 MHz, CDCl3) δ 8.13À8.09 (m, 2H), 7.94 (d,
J = 16.2 Hz, 1H), 7.79À7.64 (m, 4H), 7.51À7.45 (m, 1H), 7.32 (d, J =
16.2 Hz, 1H), 7.26À7.20 (m, 3H), 2.51 (s, 3H); 13C NMR (75 MHz,
CDCl3) δ 156.2, 148.3, 136.6, 136.4, 135.6, 132.2, 130.7, 130.2, 129.8,
129.3, 128.6, 127.6, 127.4, 126.4, 126.2, 125.9, 119.4, 20.1. HRMS calcd
for C18H15N: 245.1204. Found: 245.1201.
(E)-2-(2-(Trifluoromethyl)styryl)quinoline (3af). White solid (E:Z >
1
99:1, 80% yield): mp 93À95 °C; H NMR (300 MHz, CDCl3) δ 8.18
(d, J = 8.7 Hz, 1H), 8.12 (d, J = 8.4 Hz, 1H), 8.02À7.91 (m, 2H), 7.81
(d, J = 8.1 Hz, 1H), 7.77À7.72 (m, 3H), 7.70À7.40 (m, 4H); 13C NMR
(75 MHz, CDCl3) δ 155.6, 148.3, 136.6, 133.4, 132.2, 130.0, 129.95, 129.5,
128.2, 127.6, 127.5, 126.7, 126.3, 126.24, 126.17, 126.1, 126.0, 122.7, 118.9.
HRMS calcd for C18H12F3N: 299.0922. Found: 299.0918.
(E)-2-(4-Nitrostyryl)quinoline (3ag).16 Light yellow solid (E:Z >
1
99:1, 94% yield): mp 170À172 °C; H NMR (300 MHz, CDCl3) δ
8.26 (d, J = 9.0 Hz, 2H), 8.20 (d, J = 8.4 Hz, 1H), 8.12 (d, J = 8.4 Hz, 1H),
7.84À7.72 (m, 5H), 7.68 (d, J = 8.4 Hz, 1H), 7.41À7.35 (m, 2H); 13C
NMR (75 MHz, CDCl3) δ 154.7, 148.3, 147.5, 143.0, 136.8, 133.2,
131.8, 131.0, 130.2, 129.4, 128.9, 127.7, 126.9, 124.2, 119.8. HRMS calcd
for C17H12N2O2: 276.0899. Found: 276.0904.
(E)-2-(2-Nitrostyryl)quinoline (3ah).13 Light yellow solid (E:Z > 99:1,
90% yield): mp 102À104 °C; 1H NMR (300 MHz, CDCl3) δ 8.18 (d,
J = 8.7 Hz, 1H), 8.14À8.08 (m, 2H), 8.02 (d, J = 8.1 Hz, 1H), 7.89 (d, J =
7.8 Hz, 1H), 7.83À7.68 (m, 3H), 7.65 (d, J = 7.8 Hz, 1H), 7.64À7.47
(m, 2H), 7.42 (d, J = 16.2 Hz, 1H); 13C NMR (75 MHz, CDCl3) δ
155.2, 148.3, 148.2, 136.7, 134.3, 133.4, 132.4, 130.0, 129.5, 129.2, 128.9,
128.6, 127.6, 126.8, 124.9, 119.1. HRMS calcd for C17H12N2O2:
276.0899. Found: 276.0901.
(E)-2-(2-(Naphthalen-1-yl)vinyl)quinoline (3ao).6 Yellow solid (E:Z
> 99:1, 91% yield): mp 103À105 °C; 1H NMR (300 MHz, CDCl3) δ
8.53 (d, J = 16.2 Hz, 1H), 8.34 (d, J = 8.4 Hz, 1H), 8.16 (t, J = 8.1 Hz,
2H), 7.93À7.70 (m, 6H), 7.59À7.46 (m, 5H); 13C NMR (75 MHz,
CDCl3) δ 156.0, 148.3, 136.4, 134.0, 133.8, 131.7, 131.5, 131.4, 129.8,
129.3, 129.0, 128.7, 127.6, 127.4, 126.4, 126.3, 126.0, 125.7, 124.2, 123.8,
119.6. HRMS calcd for C21H15N: 281.1204. Found: 281.1202.
(E)-2-(2-(Furan-2-yl)vinyl)quinoline (3ap).6 Yellow oil (E:Z > 99:1,
79% yield): 1H NMR (300 MHz, CDCl3) δ 8.10 (dd, J1 = 8.4 Hz, J2 = 3.3
Hz, 2H), 7.78À7.67 (m, 2H), 7.61À7.45 (m, 4H), 7.29 (d, J = 16.2 Hz,
(E)-2-(4-Methoxystyryl)quinoline (3ai).17 Light yellow solid (E:Z >
1
99:1, 87% yield): mp 125À127 °C; H NMR (300 MHz, CDCl3) δ
8.12À8.06 (m, 2H), 7.77 (d, J = 8.1 Hz, 1H), 7.70À7.57 (m, 5H),
7.50À7.45 (t, 1H), 7.29 (d, J = 16.5 Hz, 1H), 6.93 (d, J = 8.9 Hz, 2H),
3.84 (s, 3H); 13C NMR (75 MHz, CDCl3) δ 160.2, 156.4, 148.3, 136.3,
134.2, 130.7, 129.8, 129.4, 129.1, 128.7, 127.6, 127.3, 126.9, 126.4, 126.0,
119.2, 114.3, 55.4. HRMS calcd for C18H15NO: 261.1154. Found: 261.1155.
(E)-2-(2-Methoxystyryl)quinoline (3aj). Yellow oil (E:Z > 99:1,
76% yield): 1H NMR (300 MHz, CDCl3) δ 8.14À8.09 (m, 2H), 8.03
1H), 6.56 (d, J = 3 Hz, 1H), 6.47 (dd, J1 = 9.0 Hz, J2 = 1.8 Hz, 1H); 13
C
NMR (75 MHz, CDCl3) δ 155.7, 153.0, 148.3, 143.3, 136.54, 136.49,
129.9, 129.2, 127.6, 127.4, 126.8, 126.2, 122.0, 120.0, 112.1, 111.4, 111.3.
HRMS calcd for C15H11NO: 221.0841. Found: 221.0843.
(E)-2-(2-(Thiophen-2-yl)vinyl)quinoline (3aq). Light yellow solid
(E:Z = 99:1, 70% yield): mp 89À91 °C; 1H NMR (300 MHz, CDCl3)
6853
dx.doi.org/10.1021/jo2008934 |J. Org. Chem. 2011, 76, 6849–6855

The Journal of Organic Chemistry
NOTE
δ 8.10 (t, J = 8.1 Hz, 2H), 7.86 (d, J = 15.9 Hz, 1H), 7.77 (d, J = 8.1 Hz,
1H), 7.70 (t, J = 7.8 Hz, 1H), 7.58 (d, J = 8.7, 1H), 7.52À7.46 (m, 1H),
7.31À7.19 (m, 3H), 7.05 (t, J = 4.2 Hz, 1H); 13C NMR (75 MHz,
CDCl3) δ 155.7, 148.4, 142.2, 136.51, 136.46, 129.93, 129.89, 129.2,
128.25, 128.16, 127.9, 127.6, 127.5, 127.4, 126.24, 126.22, 126.15, 119.5.
HRMS calcd for C15H11NS: 237.0612. Found: 237.0610.
(E)-2-(2-(Pyridin-2-yl)vinyl)quinoline (3ar). Light yellow solid
(E:Z > 99:1, 81% yield): mp 95À97 °C; 1H NMR (400 MHz, CDCl3)
δ 8.65 (dq, J1 = 4.8 Hz, J2 = 0.8 Hz, 1H), 8.12 (dd, J1 = 11.6 Hz, J2 = 8.8
Hz, 2H), 7.83 (d, J = 6.0 Hz, 2H), 7.80À7.77 (m, 1H), 7.73À7.65
(m, 3H), 7.58À7.55 (m, 1H), 7.53À7.48 (m, 1H), 6.97 (d, J1 = 7.6 Hz,
1H, J2 = 4.8 Hz, J3 = 1.2 Hz, 1H); 13C NMR (100 MHz, CDCl3) δ 155.4,
155.2, 149.9, 148.4, 136.7, 136.6, 133.9, 132.7, 129.9, 129.5, 127.7, 127.6,
126.5, 122.92, 122.87, 120.43. HRMS calcd for C16H12N2: 232.1000.
Found: 232.1005.
(m, 2H), 7.68À7.60 (m, 4H), 7.55À7.52 (m, 2H), 7.43À7.38 (m, 3H),
7.34À7.30 (m, 1H), 2.53 (s, 3H); 13C NMR (100 MHz, CDCl3) δ
154.2, 145.8, 135.7, 135.2, 134.8, 133.1, 131.2, 128.1, 127.92, 127.89,
127.6, 126.5, 126.3, 125.6, 118.3, 20.7. HRMS calcd for C18H15N:
245.1204. Found: 245.1206.
(E)-6-Nitro-2-styrylquinoline (3fa). Yellow solid (E:Z > 99:1, 88%
yield): mp 192À194 °C; 1H NMR (400 MHz, CDCl3) δ 8.73 (d, J =
2.4 Hz, 1H), 8.46 (dd, J1 = 9.2 Hz, J2 = 2.8 Hz, 1H), 8.28 (d, J = 8.4 Hz,
1H), 8.18 (d, J = 9.2 Hz, 1H), 7.84 (d, J = 16.0 Hz, 1H), 7.77 (d, J = 8.8
Hz, 1H), 7.67À7.64 (m, 2H), 7.45À7.35 (m, 4H); 13C NMR (100
MHz, CDCl3) δ 159.4, 150.5, 145.2, 138.2, 137.4, 136.0, 130.8, 129.6,
129.1, 127.85, 127.78, 126.1, 124.4, 123.5, 121.5. HRMS calcd for
C17H12N2O2: 276.0899. Found: 276.0896.
(E)-6-Bromo-2-styrylquinoline (3ga).13 White solid (E:Z > 99:1,
83% yield): mp 168À170 °C; 1H NMR (400 MHz, CDCl3) δ 8.02 (d,
J = 8.8 Hz, 1H), 7.97À7.92 (m, 2H), 7.78À7.62 (m, 5H), 7.42À7.31 (m,
4H); 13C NMR (100 MHz, CDCl3) δ 156.4, 146.8, 136.4, 135.6, 135.4,
133.4, 130.9, 129.7, 129.03, 128.98, 128.5, 128.4, 127.5, 120.3, 120.1.
HRMS calcd for C17H12BrN: 309.0153. Found: 309.0152.
2-((1E,3E)-4-Phenylbuta-1,3-dienyl)quinoline (3as).6 Light yellow
solid (E:Z = 93:7, 90% yield): mp 117À119 °C; 1H NMR (400 MHz,
CDCl3) δ 8.11À8.06 (m, 2H), 7.77À7.66 (m, 2H), 7.58À7.46 (m, 5H),
7.40À7.25 (m, 3H), 7.10À7.02 (dd, J1 = 15.6 Hz, J2 = 10.8 Hz, 1H), 6.97
(d, J = 15.6 Hz, 1H), 6.86 (d, J = 15.6 Hz, 1H), 6.59 (d, 0.16H); 13C
NMR (100 MHz, CDCl3) δ 156.0, 148.2, 138.0, 137.5, 137.1, 136.5,
136.3, 136.1, 135.6, 135.3, 132.7, 130.0, 129.71, 129.68, 129.2, 128.88,
128.81, 128.7, 128.3, 128.2, 127.61, 127.55, 127.4, 127.1, 126.93, 126.87,
126.7, 126.35, 126.32, 123.1, 119.5. HRMS calcd for C19H15N:
257.1204. Found: 257.1205.
(E)-2-(2-Cyclohexylvinyl)quinoline (3at). Light yellow oil (E:Z =
99:1, 71% yield). 1H NMR (300 MHz, CDCl3) δ 8.04 (dd, J1 = 8.1 Hz, J2
= 5.6 Hz, 2H), 7.74 (d, J = 8.1 Hz, 1H), 7.69À7.63 (m, 1H), 7.53 (d, J =
8.9 Hz, 1H), 7.48À7.42 (m, 1H), 6.78 (dd, J1 = 16.2 Hz, J2 = 6.3 Hz,
1H), 6.68 (d, J = 16.2 Hz, 1H), 2.30À2.21 (m, 1H), 1.91À1.68 (m, 4H),
1.43À1.19 (m, 6H); 13C NMR (75 MHz, CDCl3) δ 156.9, 148.2, 143.6,
136.3, 129.6, 129.2, 128.8, 127.5, 127.3, 125.9, 118.9, 41.3, 37.7, 26.3,
26.2, 25.9. HRMS calcd for C17H19N: 237.1517. Found: 237.1514.
(E)-2-(4-Methylpent-1-enyl)quinoline (3au). Light yellow oil (E:Z >
99:1, 78% yield): 1H NMR (400 MHz, CDCl3) δ 8.05 (dd, J1 = 8.4 Hz,
J2 = 3.6 Hz, 2H), 7.74 (dd, J1 = 8.4 Hz, J2 = 1.2 Hz, 1H), 7.69À7.64 (m,
1H), 7.53 (d, J = 8.8 Hz, 1H), 7.48À7.43 (m, 1H), 6.83À6.77 (m, 1H),
6.72 (d, J = 16.0 Hz, 1H), 2.25À2.20 (m, 2H), 1.90À1.70 (m, 1H), 0.99
(d, J = 6.8 Hz, 6H); 13C NMR (100 MHz, CDCl3) δ 156.5, 148.1, 137.0,
136.3, 132.2, 129.7, 129.2, 127.5, 127.3, 126.0, 118.8, 42.6, 28.5, 22.6.
HRMS calcd for C15H17N: 211.1361. Found: 211.1364.
(E)-4-Phenyl-2-styrylquinoline (3ba). White solid (E:Z = 92:8, 91%
yield): mp 145À147 °C; 1H NMR (400 MHz, CDCl3) δ 8.18 (d, J = 8.4
Hz, 1H), 7.86 (dd, J1 = 8.4 Hz, J2 = 0.8 Hz, 1H), 7.74À7.62 (m, 5H),
7.56À7.32 (m, 10H); 13C NMR (100 MHz, CDCl3) δ 155.5, 149.2,
138.4, 136.6, 135.0, 129.9, 129.7, 129.5, 129.4, 129.0, 128.9, 128.8,
128.63, 128.55, 128.4, 128.1, 127.5, 126.5, 126.2, 125.9, 125.8, 119.6.
HRMS calcd for C23H17N: 307.1361. Found: 307.1365.
(E)-1-(4-Phenyl-2-styrylquinolin-3-yl)ethanone (3ca). White solid
(E:Z > 99:1, 80% yield): mp 189À191 °C; 1H NMR (400 MHz, CDCl3)
δ 8.19 (d, J = 8.4 Hz, 1H), 8.10 (d, J = 15.6 Hz, 1H), 7.76À7.71 (m, 1H),
7.63À7.53 (m, 3H), 7.53À7.50 (m, 3H), 7.46À7.31 (m, 6H), 7.22 (d,
J = 15.6 Hz, 1H), 2.09 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 205.8,
150.3, 148.0, 144.6, 137.1, 136.6, 135.3, 134.7, 130.5, 130.2, 129.6,
129.04, 128.96, 128.8, 127.8, 126.9, 126.3, 125.7, 124.1, 33.0. HRMS
calcd for C25H19NO: 349.1467. Found: 349.1466.
(E)-6-Chloro-2-styrylquinoline (3ha).13 White solid (E:Z = 91:9, 86%
yield): mp 156À158 °C; 1H NMR (400 MHz, CDCl3) δ 8.03 (dd, J1 =
8.4 Hz, J2 = 3.2 Hz, 2H), 7.76À7.62 (m, 6H), 7.43À7.26 (m, 4H); 13
C
NMR (100 MHz, CDCl3) δ 156.3, 146.6, 136.5, 135.7, 135.3, 132.0, 130.9,
130.8, 129.2, 129.01, 128.98, 128.52, 128.45, 128.2, 128.0, 127.5, 126.4,
123.1, 120.3. HRMS calcd for C17H12ClN: 265.0658. Found: 265.0665.
(E)-8-Methoxy-2-styrylquinoline (3ia).6 Colorless oil (E:Z > 99:1,
90% yield): 1H NMR (400 MHz, CDCl3) δ 8.08 (d, J = 4.4 Hz, 1H),
7.74 (d, J = 8.4 Hz, 1H), 7.64À7.51 (m, 4H), 7.43À7.30 (m, 5H), 7.04
(dd, J1 = 7.6 Hz, J2 = 1.2 Hz, 1H), 4.10 (s, 3H); 13C NMR (100 MHz,
CDCl3) δ 155.27, 155.25, 140.1, 136.7, 136.4, 134.1, 129.7, 128.9, 128.6,
128.5, 127.3, 126.5, 119.5, 119.3, 108.1, 56.2. HRMS calcd for
C18H15NO: 261.1154. Found: 261.1150.
N-(2-(8-Chloroquinolin-2-yl)-1-phenylethyl)-4-methylbenzenesul-
fonamide (4ja).18 White solid (82% yield): mp 169À171 °C; 1H NMR
(400 MHz, CDCl3) δ 8.16 (d, J = 6.0 Hz, 1H), 7.94 (d, J = 8.4 Hz, 1H),
7.86 (dd, J1 = 7.2 Hz, J2 = 1.2 Hz, 1H), 7.66 (dd, J1 = 8.4 Hz, J2 = 1.2 Hz,
1H), 7.54 (d, J = 8.4 Hz, 2H), 7.45 (t, J = 8.0 Hz, 1H), 7.22À7.19 (m,
2H), 7.14À7.09 (m, 3H), 7.04 (d, J = 8.0 Hz, 1H), 6.93 (d, J = 8.4 Hz,
2H), 4.86 (m, 1H), 3.35À3.30 (m, 1H), 3.27À3.20 (m, 1H), 2.25 (s,
3H); 13C NMR (100 MHz, CDCl3) δ 159.4, 143.4, 142.5, 141.1, 138.1,
137.4, 133.3, 130.0, 129.1, 128.3, 128.1, 127.2, 127.0, 126.9, 126.7, 126.5,
123.1, 57.3, 43.8, 21.5. HRMS calcd for C24H21ClN2O2S: 436.1012.
Found: 436.1018. Crystal Data for 4ja. Empirical formula:
C24H21ClN2O2S, MW = 436.94, T = 293(2) K, λ = 0.71073 Å,
tetragonal, P42/n, a = 22.6880 (5) Å, b = 22.6880 (5) Å, c = 8.4809
(3) Å, R = 90.00°, β = 90.00°, γ = 90.00°, V = 4365.5 (2) Å3, Z = 8,
D
calcd = 1.330 mg/m3, F(000) = 1824. Crystal size 0.36 Â 0.32 Â 0.26 mm,
independent reflections 3836 [R(int) = 0.0310], reflections collected
13919, refinement method, full-matrix least-squares on F2, goodness-of-
fit on F2 1.069, final R indices [I > 2σ(I)] R1 = 0.0541, wR2 = 0.1708, R
indices (all data) R1 = 0.0824, wR2 = 0.1838, Largest diff. peak and hole
1.557 and À0.232 e ÅÀ3
.
3
N-(2-(Benzo[h]quinolin-2-yl)-1-phenylethyl)-4-methylbenzenesul-
fonamide (4ka). Light yellow solid (60% yield): mp 124À126 °C; 1H
NMR (400 MHz, CDCl3) δ 9.26 (d, J = 7.2 Hz, 1H), 7.94À7.92 (m,
2H), 7.86À7.72 (m, 3H), 7.59 (d, J = 8.8 Hz, 1H), 7.47 (s, 1H),
7.32À7.17 (m, 7H), 7.09 (d, J = 8.0 Hz, 1H), 6.70 (d, J = 8.0 Hz, 1H),
4.80À4.70 (m, 1H), 3.30À3.20 (m, 2H), 2.13 (s, 3H); 13C NMR (100
MHz, CDCl3) δ 156.7, 145.7, 142.5, 141.6, 137.2, 136.8, 133.9, 131.0,
129.0, 128.7, 128.5, 128.1, 127.8, 127.7, 127.4, 126.9, 126.8, 125.1, 125.0,
124.4, 122.5, 58.1, 44.9, 21.4. HRMS calcd for C28H24N2O2S: 452.1558.
Found: 452.1565.
(E)-6-Methoxy-2-styrylquinoline (3da).6 White solid (E:Z > 99:1,
77% yield): mp 149À151 °C; 1H NMR (400 MHz, CDCl3) δ 7.99 (d,
J = 8.8 Hz, 2H), 7.63À7.58 (m, 4H), 7.40À7.28 (m, 5H), 7.03 (d, J = 2.8
Hz, 1H), 3.91 (s, 3H); 13C NMR (100 MHz, CDCl3) δ157.8, 153.8, 144.2,
136.8, 135.3, 133.5, 130.6, 129.0, 128.9, 128.5, 128.4, 127.3, 122.5, 119.6,
105.4, 55.7. HRMS calcd for C18H15NO: 261.1154. Found: 261.1155.
(E)-6-Methyl-2-styrylquinoline (3ea).13 White solid (E:Z > 99:1, 84%
4-Methyl-N-(1-phenyl-2-(quinolin-2-yl)propyl)benzenesulfonamide
1
1
yield): mp 136À138 °C; H NMR (400 MHz, CDCl3) δ 8.03À7.98
(4la).4 Light yellow oil (dr = 1.8:1, 70% yield): H NMR (400 MHz,
6854
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The Journal of Organic Chemistry
NOTE
CDCl3) δ 8.09 (d, J = 8.4 Hz, 1.56H), 7.88 (dd, J1 = 8.4 Hz, J2 = 5.6 Hz,
1.56H), 7.75À7.70 (m, 3.12H), 7.54À7.51 (m, 1.56H), 7.47 (d, J = 6.8
Hz, 1.0H), 7.39 (d, J = 8.0 Hz, 2.0H), 7.28À7.24 (m, 1.4), 7.15À7.13
(m, 3.5H), 7.07À7.01 (m, 5H), 6.97À6.89 (m, 3.6H), 6.70 (d, J = 8.0
Hz, 1.12H), 4.62 (t, J = 6.0 Hz, 1.0H), 4.54 (t, J = 4.4 Hz, 0.56H),
3.34À3.32 (m, 1.56H), 2.25 (s, 3.0H), 2.17 (s, 1.68H), 1.29 (d, J = 6.8
Hz, 3.0H), 1.25 (d, J = 7.2 Hz, 1.68H); 13C NMR (100 MHz, CDCl3) δ
163.0, 162.4, 147.3, 147.0, 142.5, 142.4, 140.9, 139.7, 138.1, 137.0, 136.8,
136.6, 129.9, 129.86, 129.7, 129.2, 129.0, 128.94, 128.89, 128.1, 128.0,
127.6, 127.5, 127.2, 127.1, 127.07, 127.02, 126.9, 126.8, 126.5, 126.47,
126.4, 121.2, 120.8, 62.9, 61.8, 47.5, 46.6, 21.42, 21.36, 19.2, 14.3. HRMS
calcd for C25H24N2O2S: 416.1558. Found: 416.1555.
(E)-1-Styrylisoquinoline (3ma). White solid (E:Z > 99:1, 78% yield):
mp 116À118 °C; 1H NMR (400 MHz, CDCl3) δ 8.55 (d, J = 5.6 Hz,
1H), 8.35 (d, J = 8.0 Hz, 1H), 7.99 (s, 2H), 7.81 (d, J = 8.0 Hz, 1H),
7.71À7.58 (m, 4H), 7.55 (d, J = 5.6 Hz, 1H), 7.43À7.38 (m, 2H),
7.35À7.30 (m, 1H); 13C NMR (100 MHz, CDCl3) δ 154.6, 142.5,
137.0, 136.9, 136.1, 130.0, 128.9, 128.7, 127.6, 127.4, 127.3, 126.9, 124.6,
122.9, 120.0. HRMS calcd for C17H13N: 231.1048. Found: 231.1053.
(E)-2-Methyl-6-styrypyridine (3oa).6 Yellow oil (E:Z > 99:1, 35%
yield): 1H NMR (400 MHz, CDCl3) δ 7.60À7.53 (m, 4H), 7.39À7.34
(m, 2H), 7.31À7.28 (m, 1H), 7.25 (d, J = 8.4 Hz, 1H), 7.18 (d, J = 16.0
Hz, 1H), 7.02 (d, J = 7.6 Hz, 1H), 2.59 (s, 3H); 13C NMR (100 MHz,
CDCl3) δ 158.4, 155.2, 136.9, 132.7, 129.1, 128.8, 128.44, 128.35, 127.2,
127.3, 121.9, 118.9, 24.7. HRMS calcd for C14H13N: 195.1048. Found:
195.1045.
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’ ASSOCIATED CONTENT
Supporting Information. 1H and 13C NMR spectra and
S
b
crystal data. This material is available free of charge via the
Internet at http://pubs.acs.org.
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’ AUTHOR INFORMATION
Corresponding Author
*E-mail: zwang3@ustc.edu.cn.
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’ ACKNOWLEDGMENT
We are grateful to the Natural Science Foundation of China
(20932002, 20972144, 2010CB912103, and 90813008), the
Chinese Academy of Sciences, and the Graduate Innovation
Fund of USTC for support.
(17) Wang, D.-W.; Wang, X.-B.; Wang, D.-S.; Lu, S.-M.; Zhou, Y.-G.;
Li, Y.-X. J. Org. Chem. 2009, 74, 2780.
’ REFERENCES
(18) CCDC-790188 contains the supplementary crystallographic
data for 4ja. The data can be obtained free of charge from The
Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/
data_request/cif.
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