Synthesis of Quinolines from Allylic Alcohols via Iridium-Catalyzed Tandem Isomerization/Cyclization Combined with Potassium Hydroxide

Article abstract of DOI:10.1055/s-0034-1380110

A new tandem catalytic process has been established for the synthesis of quinolines. This process utilizes the [IrCp?Cl₂]₂/KOH catalyzed isomerization/cyclization of allylic alcohols with 2-aminobenzyl alcohol. Both the secondary and primary allylic alcohols were investigated in this catalytic system to afford different substituted quinoline derivatives in moderate to good yields. A mechanism study showed the reaction following a tandem process integrating isomerization of allylic alcohols and oxidative cyclization of 2-aminobenzyl alcohol.

Full text of DOI:10.1055/s-0034-1380110

SYNTHESIS
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© Georg Thieme Verlag Stuttgart · New York
2015, 47, 976–984
paper
976
S.-j. Chen et al.
Paper
Synthesis
Synthesis of Quinolines from Allylic Alcohols via Iridium-
Catalyzed Tandem Isomerization/Cyclization Combined with
Potassium Hydroxide
Shu-jie Chen
Guo-ping Lu
Chun Cai*
R4
R4
N
R3
[IrCp*Cl2]2
KOH
R3
R2
R2
OH
NH2
+
HO
R1
R1
toluene, 100 °C
Chemical Engineering College, Nanjing University of Science &
Technology, 200 Xiaolingwei, Nanjing, Jiangsu 210094, P. R. of
China
26 examples
up to 88% yield
c.cai@mail.njust.edu.cn
Received: 23.10.2014
Accepted after revision: 19.12.2014
Published online: 28.01.2015
lyzed by transition-metal complexes. In recent years there
has been significant use of allylic alcohols as synthetic eno-
late equivalents in tandem isomerization/C–X bond forma-
tion reactions. The Grée,4 Martín-Matute,5 and Li groups6
have performed much excellent work in this field. A series
of electrophiles, including aldehydes, imines, F+, Cl+, and Br+,
have been used in the isomerization processes [Scheme 1
(b)].4–6 In addition, allylic alcohols have also been developed
as ketone equivalents in tandem isomerization/C–H activa-
tion and tandem isomerization/amination.7,8
DOI: 10.1055/s-0034-1380110; Art ID: ss-2014-h0646-op
Abstract A new tandem catalytic process has been established for the
synthesis of quinolines. This process utilizes the [IrCp*Cl2]2/KOH cata-
lyzed isomerization/cyclization of allylic alcohols with 2-aminobenzyl al-
cohol. Both the secondary and primary allylic alcohols were investigat-
ed in this catalytic system to afford different substituted quinoline
derivatives in moderate to good yields. A mechanism study showed the
reaction following a tandem process integrating isomerization of allylic
alcohols and oxidative cyclization of 2-aminobenzyl alcohol.
Quinolines and their derivatives are heterocycles that
play an important role in pharmaceutical and agricultural
chemistry, as well as in the total synthesis of natural prod-
ucts.9 A great many synthetic routes are documented for
the formation of quinoline, such as Combes, Conrad–
Limpach, Doebner–Miller, Friedländer, Skraup, Povarov, and
Camps quinoline syntheses. Among them, the Friedländer
annulation is one of the most simple and straightforward
approaches for the synthesis of quinoline derivatives, but
the existing drawback is that 2-aminobenzaldehyde is both
expensive and unstable. In 2001, Shim and co-workers pro-
posed a modified Friedländer quinoline synthesis that uses
2-aminobenzyl alcohol instead of 2-aminobenzaldehyde as
the substrate. In their approach, 2-aminobenzyl alcohol is
oxidatively cyclized with ketones via hydrogen-transfer
processes by a ruthenium/potassium hydroxide catalytic
system.10 Since then, different transition-metal complexes
derived from ruthenium,11 palladium,12 iridium,13 rhodi-
um,14 and copper15 have been synthesized and applied for
the catalysis of this indirect Friedlander reaction.16 In our
previous work, we reported an iridium-catalyzed allylation
of indoles utilizing allylic alcohols as the allylating agents.17
Continuing our work of utilizing allylic alcohols as building
blocks in organic synthesis, here, we wish to disclose an
iridium/base catalytic system for indirect Friedländer quin-
oline synthesis that uses readily accessible allylic alcohols
Key words iridium, quinolines, allylic alcohol, isomerization, cycliza-
tion
Ketones and aldehydes, as one of the most important
building blocks in organic chemistry, are widely used in the
synthesis of natural products, drugs, and functional materi-
als. Oxidation of the corresponding alcohols to ketones or
aldehydes is a practical and efficient synthetic route, but it
usually requires stoichiometric amount of oxidant or liber-
ates hydrogen as a waste product, which is not consistent
with the demands of green chemistry and atom economy.
In this regard, the internal redox isomerization of allylic al-
cohols is an atom-economic and environmentally friendly
alternative that avoids the use of costly and/or toxic oxi-
dants and maintains 100% atom economy. Transition-metal
complexes derived from molybdenum and group 8, 9, and
10 metals have been predominantly employed for this
transposition, with ruthenium and rhodium species show-
ing the best performance [Scheme 1 (a)].1 Reports on the
iridium-catalyzed transposition of allylic alcohols are rela-
tively rare.2
The tandem approach is an appealing strategy that uti-
lizes two or more transformations of an organic substrate in
a single procedure.3 Furthermore, enolates are key interme-
diates in the isomerization process of allylic alcohols cata-
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2015, 47, 976–984

977
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Synthesis
(a)
redox isomerization
[M]cat
OH R3
O
R3
R1
(b)
R4
R1
R4
M = Ru, Rh, Ir, Fe, Co,
Ni, Mo, Pt, Os, etc.
R2
R2
O
100% atom economy
[M]cat
O[M]
OH
''E''
R1
R2
R1
R2
R1
R2
[M]cat
E
''E'' = electrophile
(aldehyde, imine, F+, Cl+, Br+)
this work
[M] = Ir
R2
O
OH
Ir/base
+
R1
R2
N
R1
NH2
Scheme 1 Transformation of allylic alcohols
as the ketone precursors via iridium-catalyzed tandem
isomerization/cyclization with 2-aminobenzyl alcohols to
assemble the valuable substituted quinolines.
using only one equivalent of 2a resulted in a moderate yield
(entry 13). In the absence of the iridium catalyst, 3a was
formed in a low yield (entry 14).
We began our studies by utilizing 2-aminobenzyl alco-
hol (1a) and allylic alcohol (2a) as the model substrates.
Dichloro(pentamethylcyclopentadienyl)iridium dimer
[IrCp*Cl2]2,18 introduced by Martín-Matute and co-workers
in an iridium-catalyzed 1,3-hydrogen shift/fluorination of
allylic alcohols,5b was chosen as the precatalyst. The results
are summarized in Table 1. Treatment of 1a with two equiv-
alents of 2a in the presence of catalytic amounts of
[IrCp*Cl2]2 (1 mol%) in toluene at 80 °C for 20 hours did not
afford the desired product, but only the isomerization of al-
lylic alcohol was observed (entry 1). When one equivalent
of sodium hydroxide was added, 3-methyl-2-phenylquino-
line (3a) was obtained in 23% yield (entry 2). Then screen-
ing of bases was carried out (entries 3–6); among the tested
bases, potassium hydroxide was the most effective giving
the product 3a in 83% yield (entry 3). Organic base triethyl-
amine and weak base sodium carbonate were totally inef-
fective in this transformation, and only the isomerization of
allylic alcohol was observed (entries 5 and 6). A higher yield
(93%) was obtained in a shorter period of time by elevating
the temperature to 100 °C (entry 7). Dioxane, which was a
superior solvent in the previous report, resulted in a low
yield,11a while tetrahydrofuran afforded a moderate yield
(entries 8 and 9). Attempts to decrease the reaction tem-
perature and reduce the amount of potassium hydroxide
resulted in low yields of product 3a (entries 10 and 11). It
should be noted that the yield of product 3a dramatically
reduced when the reaction was carried out under an atmo-
sphere of air (entry 12). In addition, two equivalents of al-
lylic alcohol 2a were necessary to give satisfactory yields,
Table 1 Optimization of Reaction Conditionsa
OH
OH
[IrCp*Cl2]2
+
solvent, base
Ph
NH2
1a
N
Ph
2a
3a
Entry Solvent
Base (mol%)
Temp
(°C)
Time
(h)
GC yieldb
(%) of 3a
c
1
2
toluene
toluene
toluene
toluene
toluene
toluene
toluene
dioxane
THF
none
80
80
80
80
80
20
20
20
20
20
20
12
12
12
12
12
12
12
12
–
NaOH (100)
KOH (100)
t-BuOK (100)
Et3N (100)
23
83
78
3
4
c
5
–
c
6
Na2CO3 (100)
KOH (100)
KOH (100)
KOH (100)
KOH (10)
80
100
100
100
100
60
–
7
93
37
53
50
6
8
9
10
11
12d
13e
14
toluene
toluene
toluene
toluene
toluene
KOH (100)
KOH (100)
KOH (100)
KOH (100)
100
100
100
10
62
28
a Reaction conditions: 1a (0.2 mmol), 2a (0.4 mmol), [IrCp*Cl2]2 (1 mol%
based on 1a), base (1 equiv), solvent (1 mL), N2.
b GC yield of 3a based on 1a.
c Not found.
d 2a (0.2 mmol).
e Reaction was performed under an atmosphere of air.
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2015, 47, 976–984

978
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Synthesis
To evaluate the scope of the reaction, a variety of sec-
ondary allylic alcohols 2a–o, including α-aryl- and α-alkyl-
substituted allylic alcohols substrates, were subjected to
the optimized reaction conditions (Table 1, entry 7), as
summarized in Table 2. The reactions of 2-aminobenzyl al-
cohol (1a) with electron-rich and electron-deficient α-aryl
allylic alcohols 2c–h containing para, meta, and ortho sub-
stitution occurred in 69–82% yield (entries 3–8). Disubsti-
tuted α-aryl allylic alcohols 2i and 2j reacted with 1a
smoothly to give the desired product 3i and 3j in 73% and
76% yields, respectively (entries 9 and 10). Heterocyclic
substituted allylic alcohols 2k–m also proved to be suitable
substrates giving the corresponding products 3k–m in good
yields (entries 11–13). Among them, 3m is a key building
block of an efficient potent PI3K inhibitor.19 The α-alkyl al-
lylic alcohol pent-1-en-3-ol (2n) reacted with 1a to give a
moderate yield of the desired quinoline 3n (entry 14),
while reactions of cyclic allylic alcohol cyclohex-2-en-1-ol
(2o) occurred in high yield (entry 15). In addition, substitu-
tion of the terminal position of the double bond by a phenyl
group did not affect the transformation (entry 16). In the
case of 5-phenylpent-1-en-3-ol (2q), the corresponding
quinoline was obtained as a regioisomeric mixture of
3q/3q′, favoring cyclization at the less-hindered α-meth-
ylene position [Scheme 2 (a)]. A starting material bearing
two allylic alcohol functional groups 2r was also investigat-
ed, it gave the corresponding product 3r in 51% yield
[Scheme 2 (b)]. Quinoline 3r contains a bisquinolines struc-
ture that could act as a latent (N,C,N)-type pincer ligand in
the metal catalytic and light-emitting materials.20 It was
noteworthy that α-aryl allylic alcohols, prepared from the
corresponding aldehyde and vinylmagnesium bromide, are
more diverse when compared with the corresponding α-
aryl ketones.
Table 2 Iridium-Catalyzed Tandem Isomerization/Cyclization of Sec-
ondary Allylic Alcohols with 2-Aminobenzyl Alcohol (1a)a
R2
OH
OH
+
R1
R2
R1
NH2
1a
N
2a–p
3a–p
Entry
2
R1
R2
Yieldb (%) of 3
1
2
2a
2b
2c
2d
2e
2f
Ph
H
81 (3a)
84 (3b)
77 (3c)
82 (3d)
78 (3e)
81 (3f)
75 (3g)
69 (3h)
73 (3i)
76 (3j)
80 (3k)
75 (3l)
78 (3m)
37 (3n)c
84 (3o)
82 (3p)
1-naphthyl
2-MeOC6H4
2-F3CC6H4
3-MeOC6H4
3-F3CC6H4
4-MeC6H4
4-ClC6H4
2,4-Cl2C6H3
3,5-(MeO)2C6H3
2-furyl
H
H
H
H
H
H
H
H
H
H
H
H
H
3
4
5
6
7
2g
2h
2i
8
9
10
11
12
13
14
15
16
2j
2k
2l
2-thienyl
2-pyridyl
Et
2m
2n
2o
2p
(CH2)3
Ph
Ph
a Reaction conditions: 1a (0.2 mmol), 2 (0.4 mmol), [IrCp*Cl2]2 (1 mol%
based on 1a), KOH (0.2 mmol), toluene (1 mL), 100 °C, 12 h, N2.
b Isolated yield based on 1a.
c 2n (0.8 mmol) was used.
Several substituted 2-aminobenzyl alcohols were then
examined, as summarized in Scheme 3. The substitution of
the aromatic ring was studied, and quinolines 3ab and 3ac
were obtained in good yields from the corresponding sub-
stituted 2-aminobenzyl alcohol 1b and 1c possessing elec-
(a)
OH
[IrCp*Cl2]2 (1 mol%)
KOH (1 equiv)
OH
Ph
+
+
toluene, 100 °C, 12 h
NH2
N
Ph
N
1a
2q
3q
3q'
isolated yield 75% (3q + 3q')
3q/3q'= 3:1
(b)
OH
OH
[IrCp*Cl2]2 (1 mol%)
KOH (2 equiv)
OH
N
N
+
NH2
toluene, 100 °C, 20 h
1a
2r
3r
isolated yield 51% (based on 2r)
1a/2r = 2:1
Scheme 2 Transformation of allylic alcohols 2q and 2r
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2015, 47, 976–984

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Synthesis
tron-donating and electron-withdrawing groups on the ar-
omatic ring. The 1-(2-aminophenyl)ethanol 1d also gave
the desired quinoline 3ad in 61% yield under a higher cata-
lyst loading and temperature.
Then, a second experiment was performed starting from
propiophenone (2ab) with the addition of 2-aminobenzyl
alcohol which gave the corresponding quinoline 3a in 84%
yield [Scheme 4 (b)]. These results were consistent with our
proposal that the reaction proceeded via a tandem isomeri-
zation/cyclization process. Finally, the third experiment
was performed with the deuterated allylic alcohol [D]-2a
and 2-aminobenzyl alcohol (1a); the corresponding quino-
line [D]-3a was obtained in 80% yield and 0.37 of one deu-
terium in the methyl group of quinoline was easily deduced
[Scheme 4 (c)]. Beyond this, approximately 35% D-incorpo-
ration in the 4-position of [D]-3a was also observed. This
result indicated that the oxidation of the benzyl alcohol was
reversible, and the Ir–H(D) species took part in this process.
This is also a powerful evidence that [Ir] played an impor-
tance role in the oxidation of the benzyl alcohol, although
transition-metal-free approaches have been developed for
this transformation.16,22
R2
R2
OH
R1
R1
OH
+
NH2
N
Ph
1b R1 = Me, R2 = H
1c R1 = Br, R2 = H
1d R1 = H, R2 = Me
2a
3ab 88%
3ac 86%
3ad 61% (2 mol%
[IrCp*Cl2]2, 125 °C)
Scheme 3 Transformation of substituted 2-aminobenzyl alcohols
Next, the reactions of various primary allylic alcohols
with 2-aminobenzyl alcohol 1a were investigated (Table 3).
Compared to the secondary allylic alcohols, the primary al-
lylic alcohols needed a longer reaction time to achieve a
satisfactory result (22 h vs. 12 h). Moreover, an aldol-type
side reaction was observed in the reaction, which resulted
in a slightly lower yield.21
(a)
O
OH
D
[IrCp*Cl2]2 (1 mol%)
KOH (1 equiv)
H(0.16 D)
H(0.35 D)
toluene, 100 °C, 12 h
100% conversion
Table 3 Iridium-Catalyzed Tandem Isomerization/Cyclization of Prima-
ry Allylic Alcohol with 2-Aminobenzyl Alcohol (1a)a
(95% D)
[D]-2ab
[D]-2a
OH
OH
R
(b)
(c)
[IrCp*Cl2]2
(1 mol%)
KOH
+
O
R
NH2
1a
N
OH
(1 equiv)
+
2s–w
3s–w
NH2
N
Ph
toluene
100 °C, 12 h
3a
Yieldb (%)
1a
2ab
Entry
2s–w
R
Quinoline
(84% isolated yield)
1
2
3
4
5
2s
H
3s
67
79
72
65
70
(0.35 D)
[IrCp*Cl2]2
(1 mol%)
KOH
H
2t
Ph
3t
H2
C
2u
2v
2w
3-MeOC6H4
4-MeC6H4
4-ClC6H4
3u
3v
3w
OH
(1 equiv)
H(0.27 D)
D
+
HO
Ph
(95% D)
[D]-2a
NH2
toluene
N
Ph
100 °C, 12 h
(80% isolated yield)
a Reaction conditions: 1a (0.2 mmol), 2 (0.4 mmol), [IrCp*Cl2]2 (1 mol%
based on 1a), KOH (0.2 mmol), toluene (1 mL), 100 °C, N2, 22 h.
b Isolated yield based on 1a.
1a
[D]-3a
Scheme 4 Transformation of substituted 2-aminobenzyl alcohols
In order to obtain more information about the mecha-
nism of this tandem isomerization–cyclization process.
Three sets of experiments with deuterium-labeled allylic
alcohol [D]-2a and propiophenone (2ab) were carried out.
Firstly, in the absence of 2-aminobenzyl alcohol, the deute-
rium-labeled allylic alcohol [D]-2a isomerized to the corre-
sponding ketone [D]-2ab under the reaction conditions.
The location of 0.35 of one deuterium in the methyl group
of propiophenone was easily deduced by a combination of
mass and NMR spectra. Moreover, 16% D-incorporation was
observed at one H of the methylene position. This indicated
that the mechanism is not a strict intramolecular 1,3-hy-
drogen shift under this catalytic system [Scheme 4 (a)].
Based on the results shown above and according to liter-
ature data,13 we propose the mechanism shown in Scheme
5.
The reaction is initiated by the formation of propiophe-
none (2ab) from allylic alcohol 2a via the iridium-catalyzed
redox isomerization process.1b Then the propiophenone
(2ab) reacted with the 2-aminobenzyl alcohol (1a) to form
the ketimine A, which is then oxidized by the [Ir] species
with another equivalent of 2ab as hydrogen acceptor to give
the corresponding aldehyde C.13 Eventually, C converted
into 3a through a potassium hydroxide mediated intramo-
lecular aldol-type condensation.
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Synthesis
N
3a
Ph
O
OH
OH
N
Ph
Ph
– H2O
O
2ab
2a
+
redox
isomerization
OH
OH
NH2
Ph
Ph
A
N
Ph
1a
D
[Ir]
transfer
hydrogenation
[IrCp*Cl2]2/KOH
KOH
O
O
Ph
O
– [Ir-H2]
IrLn
N
H
N
Ph
Ph
B
C
Scheme 5 A possible reaction pathway for the iridium-catalyzed tandem isomerization/cyclization of allylic alcohol 2a with 1a
In conclusion, we have reported the first synthesis of
substituted quinolines from allylic alcohols and 2-amino-
benzyl alcohols. A wide range of substrates include second-
ary and primary allylic alcohols were investigated using
this catalytic system to afford different substituted quino-
line derivatives in moderate to good yields. A mechanism
studies revealed that the reaction proceed by an iridium-
catalyzed tandem process. Firstly, the iridium-catalyzed
isomerization of the allylic alcohols to the corresponding
ketones that reacted with the 2-aminobenzyl alcohol to
form ketimines. The ketimines were then oxidized to the
corresponding aldehydes through a transfer hydrogenation
process. Finally, a potassium hydroxide mediated intramo-
lecular aldol-type condensation yielded the desired quino-
lines.
Quinolines 3; General Procedure
A mixture of 2-aminobenzyl alcohol 1 (0.2 mmol), allylic alcohol 2
(0.4 mmol), [IrCp*Cl2]2 (0.0020 mmol, 1.0 mol%), and KOH (0.2 mmol)
were dissolved in anhyd toluene (1 mL) in a 25-mL Schlenk tube. The
system was flushed with N2 and allowed to react at the specified tem-
perature and for the specified time. The mixture was allowed to cool
to r.t. and filtered through a short silica gel column (washed with EtO-
Ac). Removal of the solvent left an oil that was separated by column
chromatography (silica gel, EtOAc–hexane) to give the quinoline.
Secondary Allylic Alcohols; General Procedure25
In an oven-dried round-bottom flask, a solution of the aldehyde (10
mmol, 1 equiv) in anhyd THF (10 mL) was stirred for 10 min under N2
at 0 °C. To the mixture, 1 M vinylmagnesium bromide in THF (12
mmol, 1.2 equiv) was added slowly. After 15 min the mixture was al-
lowed to warm to r.t. and stirred for an additional 1–3 h. The reaction
was quenched with sat. aq NH4Cl solution and extracted with Et2O (3
× 30 mL). The combined organic layers were washed with brine, dried
(MgSO4), filtered, and evaporated to give the crude allylic alcohols
2a–n,q–r, which were used in the next step without further purifica-
tion.
Unless stated otherwise, all reactions were carried out in flame-dried
glassware under a N2 atmosphere. THF and toluene were freshly dis-
tilled from sodium benzophenone ketyl under N2. TLC were per-
formed on glass plates precoated with silica gel and visualization
with UV light (254 nm). All melting points are uncorrected. Mass
spectra were taken on a Finnigan TSQ Quantum-MS instrument. IR
spectra were recorded on Thermo Scientific Nicolet iS10. 1H, 13C, and
19F NMR spectra were recorded on an Avance 500 Bruker spectrome-
ter operating at 500, 125, and 470 MHz in CDCl3, respectively, with
respect to internal TMS. Elemental analyses were performed on a
Yanagimoto MT3CHN recorder. GC analysis were performed on an
Agilent 7890A instrument (Column: Agilent 19091J-413: 30 m × 320
μm × 0.25 μm, carrier gas: N2, FID detector. [IrCp*Cl2]223 and deuterat-
ed allylic alcohol ([D]-2a)24 were synthesized according to previous
reports.
1-Phenylprop-2-en-1-ol (2a)
Colorless oil; yield: 1313 mg (98%).
1H NMR (500 MHz, CDCl3): δ = 7.42–7.37 (m, 4 H), 7.34–7.30 (m, 1 H),
6.07 (ddd, J = 17.0, 10.2, 6.1 Hz, 1 H), 5.37 (d, J = 17.1 Hz, 1 H), 5.22 (d,
J = 10.3 Hz, 2 H), 2.33 (s, 1 H).
13C NMR (125 MHz, CDCl3): δ = 142.74, 140.37, 128.66, 127.84,
126.47, 115.21, 75.41.
(E)-3-(4-Chlorophenyl)prop-2-en-1-ol (2w); Typical Procedure26
To a solution of secondary allylic alcohol 2h (1.0 mmol) in THF–H2O
(4:1, 5 mL), methanesulfonic acid (2.0 mmol) was added dropwise
over 5 min at r.t. and stirring was continued at this temperature for 12
h (TLC monitoring). After complete conversion, the mixture was
quenched with sat. NaHCO3 solution (10 mL). The resulting mixture
was extracted with Et2O (3 × 10 mL). The combined organic layers
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2015, 47, 976–984

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Synthesis
were washed with water, dried (Na2SO4), filtered, and concentrated
under reduced pressure. The resulting crude product was purified by
column chromatography (silica gel, EtOAc–hexane) to afforded 2w
(141 mg, 84%) as a colorless oil.
1H NMR (500 MHz, CDCl3): δ = 7.35–7.23 (m, 4 H), 6.55 (d, J = 15.9 Hz,
1 H), 6.32 (dtd, J = 15.8, 5.6, 2.2 Hz, 1 H), 4.30 (d, J = 5.6 Hz, 2 H), 2.04
(s, 1 H).
13C NMR (125 MHz, CDCl3): δ = 157.90, 144.95, 138.45, 134.96,
130.77, 129.22, 128.69, 128.32, 127.90, 127.35 (q, J = 32.5 Hz), 127.34,
126.93, 125.83, 125.79, 125.60, 123.02 (q, J = 272.6 Hz), 18.59.
19F NMR (470 MHz, CDCl3): δ = –58.90.
MS (EI): m/z = 287 (M+).
Anal. Calcd for C17H12F3N: C, 71.07; H, 4.21; N, 4.88. Found: C, 71.25;
H, 4.13; N, 5.11.
13C NMR (125 MHz, CDCl3): δ = 134.22, 132.30, 128.74, 128.22,
127.76, 126.67, 62.46.
2-(3-Methoxyphenyl)-3-methylquinoline (3e)
Colorless oil; yield: 39 mg (78%).
1,3-Diphenylprop-2-en-1-ol (2p)27
1H NMR (500 MHz, CDCl3): δ = 8.17 (d, J = 8.4 Hz, 1 H), 8.04 (s, 1 H),
7.80 (d, J = 8.1 Hz, 1 H), 7.68 (dd, J = 11.3, 4.0 Hz, 1 H), 7.54 (t, J = 7.5
Hz, 1 H), 7.42 (t, J = 7.9 Hz, 1 H), 7.16 (dd, J = 10.6, 4.9 Hz, 2 H), 7.01
(dd, J = 8.1, 2.2 Hz, 1 H), 3.88 (s, 3 H), 2.48 (s, 3 H).
13C NMR (125 MHz, CDCl3): δ = 159.34, 158.59, 145.45, 141.06,
135.86, 128.36, 128.23, 127.85, 126.66, 125.72, 125.51, 120.29,
113.36, 113.17, 54.37, 19.56.
In an oven-dried round-bottom flask, a solution of chalcone (2 mmol,
1 equiv) in THF–MeOH (1:1, 10 mL) was stirred for 5 min at 0 °C. Then
NaBH4 (2.59 g, 2 mmol, 1.0 equiv) was added in one portion and the
mixture is maintained at this temperature for 30 min. Then the sol-
vent was removed under vacuum and the residue was dissolved in
Et2O (15 mL) and treated with 0.6 M HCl (1 mL). The organic layer was
separated, washed with sat. NaHCO3 until the aqueous phase had
neutral pH and then sat. NaCl, and dried (anhyd MgSO4). The solvent
was removed under vacuum to afford 2p (403 mg, 96%) as a colorless
oil which was used without further purification.
MS (EI): m/z = 249 (M+).
Anal. Calcd for C17H15NO: C, 81.90; H, 6.06; N, 5.62. Found: C, 82.06;
H, 6.27; N, 5.28.
3-Methyl-2-phenylquinoline (3a)16a
3-Methyl-2-[3-(trifluoromethyl)phenyl]quinoline (3f)
Colorless oil; yield: 35 mg (81%).
White solid; yield: 46 mg (81%); mp 86–87 °C.
1H NMR (500 MHz, CDCl3): δ = 8.16 (d, J = 8.4 Hz, 1 H), 8.04 (s, 1 H),
7.80 (d, J = 8.0 Hz, 1 H), 7.71–7.64 (m, 1 H), 7.64–7.58 (m, 2 H), 7.57–
7.48 (m, 3 H), 7.48–7.43 (m, 1 H), 2.48 (s, 3 H).
13C NMR (125 MHz, CDCl3): δ = 159.54, 145.60, 139.84, 135.81,
128.29, 127.88, 127.80, 127.33, 127.23, 126.63, 125.72, 125.45, 19.64.
1H NMR (500 MHz, CDCl3): δ = 8.12 (d, J = 8.5 Hz, 1 H), 8.06 (s, 1 H),
7.89 (s, 1 H), 7.80 (d, J = 8.0 Hz, 2 H), 7.74–7.66 (m, 2 H), 7.62 (t, J = 7.7
Hz, 1 H), 7.55 (dd, J = 11.1, 3.9 Hz, 1 H), 2.47 (s, 3 H).
13C NMR (125 MHz, CDCl3): δ = 157.83, 145.69, 140.60, 136.16,
131.30, 129.81 (q, J = 32.5 Hz), 128.34, 128.08, 127.83, 126.78, 125.85,
125.79, 124.92, 124.02, 123.14 (q, J = 270.6 Hz), 19.44.
3-Methyl-2-(naphthalen-1-yl)quinoline (3b)28
19F NMR (470 MHz, CDCl3): δ = –62.53.
MS (EI): m/z = 287 (M+).
Colorless oil; yield: 45 mg (84%).
1H NMR (500 MHz, CDCl3): δ = 8.16 (d, J = 8.4 Hz, 1 H), 8.10 (s, 1 H),
7.94 (t, J = 8.4 Hz, 2 H), 7.86 (d, J = 8.1 Hz, 1 H), 7.74–7.67 (m, 1 H),
7.59 (dt, J = 10.4, 7.1 Hz, 2 H), 7.49 (ddd, J = 8.8, 8.1, 4.4 Hz, 2 H), 7.42–
7.33 (m, 2 H), 2.21 (s, 3 H).
13C NMR (125 MHz, CDCl3): δ = 159.46, 145.66, 137.50, 135.11,
132.75, 130.50, 129.78, 128.43, 127.83, 127.49, 127.39, 126.93,
125.87, 125.63, 125.40, 125.21, 124.94, 124.49, 124.44, 18.73.
Anal. Calcd for C17H12F3N: C, 71.07; H, 4.21; N, 4.88. Found: C, 70.95;
H, 4.44; N, 4.98.
3-Methyl-2-(p-tolyl)quinoline (3g)28
Colorless oil; yield: 35 mg (75%).
1H NMR (500 MHz, CDCl3): δ = 8.16 (d, J = 8.4 Hz, 1 H), 8.03 (s, 1 H),
7.79 (d, J = 8.0 Hz, 1 H), 7.68 (dd, J = 11.2, 4.1 Hz, 1 H), 7.53 (t, J = 8.0
Hz, 3 H), 7.32 (d, J = 7.8 Hz, 2 H), 2.49 (s, 3 H), 2.45 (s, 3 H).
2-(2-Methoxyphenyl)-3-methylquinoline (3c)28
Colorless oil; yield: 38 mg (77%).
13C NMR (125 MHz, CDCl3): δ = 159.50, 145.50, 137.10, 136.79,
135.86, 128.34, 128.14, 127.99, 127.84, 126.55, 125.68, 125.36, 20.34,
19.69.
1H NMR (500 MHz, CDCl3): δ = 8.08 (d, J = 8.4 Hz, 1 H), 7.91 (s, 1 H),
7.73 (d, J = 8.1 Hz, 1 H), 7.58 (t, J = 7.6 Hz, 1 H), 7.45 (t, J = 7.5 Hz, 1 H),
7.41–7.32 (m, 1 H), 7.31–7.24 (m, 1 H), 7.04 (t, J = 7.4 Hz, 1 H), 6.94 (d,
J = 8.3 Hz, 1 H), 3.71 (s, 3 H), 2.25 (s, 3 H).
2-(4-Chlorophenyl)-3-methylquinoline (3h)
13C NMR (125 MHz, CDCl3): δ = 158.34, 155.74, 145.62, 134.33,
130.04, 129.29, 128.70, 128.35, 127.38, 126.86, 125.76, 125.27,
120.03, 109.89, 54.44, 18.26.
White solid; yield: 35 mg (69%); mp 93–94 °C.
IR (neat): 725, 748, 837, 1086, 1483, 1597, 2979, 3051 cm–1
1H NMR (500 MHz, CDCl3): δ = 8.11 (d, J = 8.4 Hz, 1 H), 8.02 (s, 1 H),
7.78 (d, J = 8.1 Hz, 1 H), 7.67 (t, J = 7.5 Hz, 1 H), 7.54 (dd, J = 15.6, 7.9
Hz, 3 H), 7.47 (d, J = 8.4 Hz, 2 H), 2.46 (s, 3 H).
.
3-Methyl-2-[2-(trifluoromethyl)phenyl]quinoline (3d)
White solid; yield: 47 mg (82%); mp 58–59 °C.
IR (neat): 751, 1107, 1121, 1312, 1736, 3062 cm–1
13C NMR (125 MHz, CDCl3): δ = 158.23, 145.68, 138.32, 135.99,
133.36, 129.36, 128.29, 127.94, 127.54, 126.67, 125.75, 125.64, 19.57.
.
1H NMR (500 MHz, CDCl3): δ = 8.10 (d, J = 8.4 Hz, 1 H), 8.02 (s, 1 H),
7.81 (dd, J = 7.9, 3.2 Hz, 2 H), 7.66 (dt, J = 15.4, 7.7 Hz, 2 H), 7.56 (dd,
J = 14.3, 7.1 Hz, 2 H), 7.38 (d, J = 7.5 Hz, 1 H), 2.22 (s, 3 H).
MS (EI): m/z = 253 (M+).
Anal. Calcd for C16H12ClN: C, 75.74; H, 4.77; N, 5.52. Found: C, 75.46;
H, 4.97; N, 5.36.
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2-(2,4-Dichlorophenyl)-3-methylquinoline (3i)
Colorless oil; yield: 42 mg (73%).
IR (neat): 754, 780, 835, 1000, 1099, 1586, 2926 cm–1
1H NMR (500 MHz, CDCl3): δ = 8.11 (d, J = 8.5 Hz, 1 H), 8.03 (s, 1 H),
7.81 (d, J = 8.1 Hz, 1 H), 7.68 (t, J = 7.4 Hz, 1 H), 7.58–7.50 (m, 2 H),
7.39 (dd, J = 8.2, 1.8 Hz, 1 H), 7.33 (d, J = 8.2 Hz, 1 H), 2.30 (s, 3 H).
13C NMR (125 MHz, CDCl3): δ = 156.85, 145.41, 137.38, 135.30,
133.82, 132.63, 130.15, 128.98, 128.46, 128.30, 128.00, 127.07,
126.50, 125.92, 18.17.
1H NMR (500 MHz, CDCl3): δ = 8.72 (d, J = 4.7 Hz, 1 H), 8.13 (d, J = 8.4
Hz, 1 H), 8.04 (s, 1 H), 7.92–7.82 (m, 2 H), 7.79 (d, J = 8.1 Hz, 1 H),
7.71–7.62 (m, 1 H), 7.57–7.48 (m, 1 H), 7.35 (ddd, J = 6.8, 4.9, 1.9 Hz, 1
H), 2.61 (s, 3 H).
13C NMR (125 MHz, CDCl3): δ = 158.12, 156.99, 147.58, 145.44,
136.38, 135.78, 129.08, 128.40, 127.73, 127.08, 125.78, 123.37,
121.97, 19.39.
.
2-Ethyl-3-methylquinoline (3n)16a
White solid; yield: 13 mg (37%); mp 50–51 °C.
MS (EI): m/z = 287 (M+).
1H NMR (500 MHz, CDCl3): δ = 8.00 (d, J = 8.4 Hz, 1 H), 7.80 (s, 1 H),
7.67 (d, J = 8.1 Hz, 1 H), 7.58 (ddd, J = 8.3, 7.0, 1.3 Hz, 1 H), 7.45–7.38
(m, 1 H), 2.97 (q, J = 7.6 Hz, 2 H), 2.45 (d, J = 0.4 Hz, 3 H), 1.35 (t, J = 7.6
Hz, 3 H).
Anal. Calcd for C16H11Cl2N: C, 66.69; H, 3.85; N, 4.86. Found: C, 66.92;
H, 3.93; N, 4.69.
2-(3,5-Dimethoxyphenyl)-3-methylquinoline (3j)
13C NMR (125 MHz, CDCl3): δ = 163.43, 146.77, 135.86, 129.52,
128.61, 128.40, 127.43, 126.79, 125.70, 29.63, 19.23, 12.98.
Colorless oil; yield: 42 mg (76%).
IR (neat): 723, 1024, 1159, 1583, 2962 cm–1
.
1,2,3,4-Tetrahydroacridine (3o)16a
1H NMR (500 MHz, CDCl3): δ = 8.13 (d, J = 8.4 Hz, 1 H), 8.01 (s, 1 H),
7.77 (d, J = 8.1 Hz, 1 H), 7.71–7.61 (m, 1 H), 7.52 (dd, J = 11.1, 3.9 Hz, 1
H), 6.71 (d, J = 2.3 Hz, 2 H), 6.55 (t, J = 2.3 Hz, 1 H), 3.84 (s, 6 H), 2.46 (s,
3 H).
13C NMR (125 MHz, CDCl3): δ = 159.73, 159.44, 145.47, 141.79,
135.71, 128.32, 128.20, 127.78, 126.69, 125.72, 125.49, 105.99, 99.56,
54.48, 19.50.
Colorless oil; yield: 31 mg (84%).
1H NMR (500 MHz, CDCl3): δ = 7.98 (d, J = 8.5 Hz, 1 H), 7.78 (s, 1 H),
7.67 (d, J = 8.1 Hz, 1 H), 7.59 (t, J = 7.6 Hz, 1 H), 7.42 (t, J = 7.5 Hz, 1 H),
3.12 (t, J = 6.6 Hz, 2 H), 2.95 (t, J = 6.4 Hz, 2 H), 2.01–1.94 (m, 2 H),
1.90–1.84 (m, 2 H).
13C NMR (125 MHz, CDCl3): δ = 158.26, 145.40, 134.17, 130.00,
127.60, 127.11, 126.21, 125.90, 124.61, 2.46, 28.23, 22.19, 21.89.
MS (EI): m/z = 279 (M+).
Anal. Calcd for C18H17NO2: C, 77.40; H, 6.13; N, 5.01. Found: C, 77.52;
H, 6.29; N, 4.95.
3-Benzyl-2-phenylquinoline (3p)12c
Yellow solid; yield: 48 mg (82%); mp 94–95 °C.
1H NMR (500 MHz, CDCl3): δ = 8.18 (d, J = 8.5 Hz, 1 H), 7.94 (s, 1 H),
7.76 (d, J = 8.1 Hz, 1 H), 7.70 (t, J = 7.4 Hz, 1 H), 7.58–7.48 (m, 3 H),
7.48–7.39 (m, 3 H), 7.26 (t, J = 7.3 Hz, 2 H), 7.21 (t, J = 7.2 Hz, 1 H), 7.02
(d, J = 7.3 Hz, 2 H), 4.15 (s, 2 H).
13C NMR (125 MHz, CDCl3): δ = 159.78, 145.69, 139.69, 139.00,
136.06, 131.56, 128.34, 128.20, 128.05, 127.91, 127.53, 127.33,
127.24, 126.58, 126.16, 125.54, 125.31, 38.15.
2-(2-Furyl)-3-methylquinoline (3k)
Colorless oil; yield: 33 mg (80%).
IR (neat): 736, 1003, 1494, 1722, 2928 cm–1
1H NMR (500 MHz, CDCl3): δ = 8.13 (d, J = 8.5 Hz, 1 H), 7.97 (s, 1 H),
7.72 (d, J = 8.0 Hz, 1 H), 7.66 (dd, J = 14.0, 5.8 Hz, 2 H), 7.48 (t, J = 7.4
Hz, 1 H), 7.12 (d, J = 3.4 Hz, 1 H), 6.60 (dd, J = 3.3, 1.7 Hz, 1 H), 2.72 (s,
3 H).
.
13C NMR (125 MHz, CDCl3): δ = 152.65, 147.98, 145.56, 142.70,
136.62, 128.20, 127.95, 127.30, 126.27, 125.62, 125.42, 111.47,
110.64, 20.30.
3-Methyl-2-phenethylquinoline (3q)31 and 3-Benzyl-2-ethylquino-
line (3q′)32
Colorless oil; yield: 37 mg (75%).
MS (EI): m/z = 209 (M+).
1H NMR (500 MHz, CDCl3): δ = 8.09 (t, J = 7.8 Hz, 1 H), 7.84 (s, 1 H),
7.77 (s, 1 H), 7.71 (t, J = 8.9 Hz, 1 H), 7.65 (t, J = 7.6 Hz, 1 H), 7.47 (dd,
J = 15.0, 7.4 Hz, 1 H), 7.37–7.27 (m, 5 H), 7.25–7.20 (m, 1 H), 7.18 (d,
J = 7.4 Hz, 1 H), 4.19 (s, 1 H), 3.28 (dd, J = 10.2, 5.6 Hz, 2 H), 3.19 (dd,
J = 10.5, 5.9 Hz, 2 H), 2.98 (q, J = 7.5 Hz, 1 H), 2.42 (s, 3 H), 1.34 (t, J =
7.5 Hz, 1 H).
Anal. Calcd for C14H11NO: C, 80.36; H, 5.30; N, 6.69. Found: C, 80.51;
H, 5.16; N, 6.82.
3-Methyl-2-(2-thienyl)quinoline (3l)29
Colorless oil; yield: 34 mg (75%).
1H NMR (500 MHz, CDCl3): δ = 8.05 (d, J = 8.5 Hz, 1 H), 7.95 (s, 1 H),
7.70 (d, J = 8.1 Hz, 1 H), 7.66–7.57 (m, 2 H), 7.45 (t, J = 6.4 Hz, 2 H),
7.20–7.09 (m, 1 H), 2.70 (s, 3 H).
1,3-Bis(3-methylquinolin-2-yl)benzene (3r)
Pale yellow solid; yield: 39 mg (51%); mp 170–171 °C.
13C NMR (125 MHz, CDCl3): δ = 151.68, 145.58, 144.18, 136.58,
128.04, 127.93, 127.32, 127.14, 126.75, 126.63, 126.23, 125.56,
125.35, 20.83.
1H NMR (500 MHz, CDCl3): δ = 8.11 (d, J = 8.5 Hz, 1 H), 8.01 (s, 1 H),
7.86 (s, 1 H), 7.76 (d, J = 8.1 Hz, 1 H), 7.71–7.66 (m, 1 H), 7.66–7.57 (m,
2 H), 7.49 (t, J = 7.5 Hz, 1 H), 2.52 (s, 3 H).
13C NMR (125 MHz, CDCl3): δ = 159.17, 145.71, 139.88, 135.89,
128.81, 128.34, 127.86, 127.77, 127.29, 126.66, 125.73, 125.47, 28.72,
19.79.
3-Methyl-2-(2-pyridyl)quinoline (3m)30
Colorless oil; yield: 34 mg (78%).
MS (EI): m/z = 360 (M+).
Anal. Calcd for C26H20N2: C, 86.64; H, 5.59; N, 7.77. Found: C, 86.86; H,
5.70; N, 7.96.
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3,6-Dimethyl-2-phenylquinoline (3ab)28
13C NMR (125 MHz, CDCl3): δ = 158.96, 151.07, 145.95, 140.26,
133.86, 132.70, 128.75, 128.20, 127.86, 127.15, 126.48, 125.68,
120.38, 113.89, 110.81, 54.20, 38.29.
Colorless oil; yield: 41 mg (88%).
1H NMR (500 MHz, CDCl3): δ = 8.02 (d, J = 8.6 Hz, 1 H), 7.92 (s, 1 H),
7.59 (d, J = 7.2 Hz, 2 H), 7.53 (s, 1 H), 7.48 (t, J = 7.5 Hz, 3 H), 7.43 (t, J =
7.3 Hz, 1 H), 2.54 (s, 3 H), 2.45 (s, 3 H).
13C NMR (125 MHz, CDCl3): δ = 159.72, 145.37, 141.12, 136.31,
136.19, 131.14, 129.21, 129.09, 128.99, 128.36, 128.15, 127.74,
125.63, 21.74, 20.72.
MS (EI): m/z = 249 (M+).
Anal. Calcd for C17H15NO: C, 81.90; H, 6.06; N, 5.62. Found: C, 82.14;
H, 6.17; N, 5.41.
3-(4-Methylbenzyl)quinoline (3v)35
Colorless oil; yield: 30 mg (65%).
6-Bromo-3-methyl-2-phenylquinoline (3ac)
1H NMR (500 MHz, CDCl3): δ = 8.83 (s, 1 H), 8.12 (d, J = 8.4 Hz, 1 H),
7.91 (s, 1 H), 7.76 (d, J = 8.1 Hz, 1 H), 7.72–7.63 (m, 1 H), 7.53 (t, J = 7.4
Hz, 1 H), 7.20–7.06 (m, 4 H), 4.15 (s, 2 H), 2.35 (s, 3 H).
Pale yellow solid; yield: 51 mg (86%); mp 91–92 °C.
IR (neat): 685, 816, 903, 1472, 1590, 2922 cm–1
.
13C NMR (125 MHz, CDCl3): δ = 150.89, 145.61, 135.56, 135.18,
134.04, 133.20, 128.46, 127.95, 127.85, 127.20, 126.46, 125.75, 37.85,
20.02.
1H NMR (500 MHz, CDCl3): δ = 7.98 (d, J = 8.9 Hz, 1 H), 7.95–7.88 (m, 2
H), 7.71 (dd, J = 8.9, 2.1 Hz, 1 H), 7.62–7.54 (m, 2 H), 7.49 (t, J = 7.3 Hz,
2 H), 7.47–7.41 (m, 1 H), 2.46 (s, 3 H).
13C NMR (125 MHz, CDCl3): δ = 161.04, 145.30, 140.58, 135.77,
132.29, 131.18, 130.44, 128.89, 128.83, 128.47, 120.32, 20.78.
3-(4-Chlorobenzyl)quinoline (3w)
Colorless oil; yield: 35 mg (70%).
MS (EI): m/z = 297 (M+).
1H NMR (500 MHz, CDCl3): δ = 8.78 (d, J = 1.9 Hz, 1 H), 8.08 (d, J = 8.4
Hz, 1 H), 7.85 (s, 1 H), 7.73 (d, J = 8.1 Hz, 1 H), 7.70–7.62 (m, 1 H), 7.52
(dd, J = 11.1, 3.9 Hz, 1 H), 7.28 (d, J = 8.4 Hz, 2 H), 7.15 (d, J = 8.3 Hz, 2
H), 4.12 (s, 2 H).
13C NMR (125 MHz, CDCl3): δ = 150.88, 145.99, 137.15, 133.87,
132.29, 131.49, 129.30, 128.22, 128.03, 127.90, 127.08, 126.45,
125.83, 37.57.
Anal. Calcd for C16H12BrN: C, 64.45; H, 4.06; N, 4.70. Found: C, 64.20;
H, 4.14; N, 4.84.
3,4-Dimethyl-2-phenylquinoline (3ad)33
Colorless oil; yield: 28 mg (61%).
1H NMR (500 MHz, CDCl3): δ = 8.12 (d, J = 8.3 Hz, 1 H), 8.05 (d, J = 8.4
Hz, 1 H), 7.66 (t, J = 7.3 Hz, 1 H), 7.60–7.52 (m, 3 H), 7.49 (t, J = 7.4 Hz,
2 H), 7.43 (t, J = 7.3 Hz, 1 H), 2.70 (s, 3 H), 2.40 (s, 3 H).
13C NMR (126 MHz, CDCl3): δ = 159.60, 144.98, 141.23, 140.89,
129.17, 127.95, 127.26, 126.92, 126.24, 126.11, 125.13, 122.37, 16.55,
13.80.
MS (EI): m/z = 253 (M+).
Anal. Calcd for C16H12ClN: C, 75.74; H, 4.77; N, 5.52. Found: C, 75.70;
H, 4.89; N, 5.44.
1-Deuterio-1-phenylprop-2-en-1-ol ([D]-2a)24
Colorless oil.
3-Methylquinoline (3s)34
1H NMR (500 MHz, CDCl3): δ = 7.39 (dd, J = 6.7, 3.4 Hz, 4 H), 7.35–7.29
(m, 1 H), 6.07 (dd, J = 17.1, 10.3 Hz, 1 H), 5.36 (dd, J = 17.1, 1.3 Hz, 1
H), 5.22 (dd, J = 10.3, 1.3 Hz, 1.05 H), 2.33 (s, 1 H).
13C NMR (125 MHz, CDCl3): δ = 142.68, 140.31, 128.67, 127.85,
126.45, 115.24, 75.02 (t, J = 22.5 Hz).
Colorless oil; yield: 19 mg (67%).
1H NMR (500 MHz, CDCl3): δ = 8.79 (d, J = 1.2 Hz, 1 H), 8.10 (d, J = 8.4
Hz, 1 H), 7.95 (s, 1 H), 7.76 (d, J = 8.1 Hz, 1 H), 7.67 (dd, J = 11.2, 4.0 Hz,
1 H), 7.53 (t, J = 7.4 Hz, 1 H), 2.54 (s, 3 H).
13C NMR (125 MHz, CDCl3): δ = 151.18, 145.30, 133.96, 129.52,
127.97, 127.60, 127.18, 126.15, 125.67, 17.75.
Compound [D]-2ab
Colorless oil.
3-Benzylquinoline (3t)21a
1H NMR (500 MHz, CDCl3): δ = 7.97 (d, J = 7.9 Hz, 2 H), 7.55 (t, J = 7.3
Hz, 1 H), 7.46 (t, J = 7.7 Hz, 2 H), 3.01 (q, J = 7.2 Hz, 1.84 H), 1.23 (q, J =
7.7 Hz, 2.65 H).
Colorless oil; yield: 35 mg (79%).
1H NMR (500 MHz, CDCl3): δ = 8.81 (d, J = 1.8 Hz, 1 H), 8.07 (d, J = 8.5
Hz, 1 H), 7.87 (s, 1 H), 7.73 (d, J = 8.2 Hz, 1 H), 7.65 (t, J = 7.6 Hz, 1 H),
7.50 (t, J = 7.5 Hz, 1 H), 7.31 (t, J = 7.5 Hz, 2 H), 7.23 (t, J = 7.7 Hz, 3 H),
4.16 (s, 2 H).
Compound [D]-3a
Colorless oil; yield: 35 mg (80%).
13C NMR (125 MHz, CDCl3): δ = 151.14, 145.94, 138.71, 133.85,
132.86, 128.22, 127.98, 127.85, 127.77, 127.15, 126.46, 125.69,
125.59, 38.28.
1H NMR (500 MHz, CDCl3): δ = 8.13 (d, J = 8.4 Hz, 1 H), 8.01 (s, 0.65 H),
7.78 (d, J = 8.1 Hz, 1 H), 7.66 (t, J = 7.6 Hz, 1 H), 7.59 (d, J = 7.3 Hz, 2 H),
7.50 (dt, J = 13.1, 7.5 Hz, 3 H), 7.43 (t, J = 7.3 Hz, 1 H), 2.46 (s, 1.84 H),
2.45 (s, 0.89 H).
3-(3-Methoxybenzyl)quinoline (3u)
13C NMR (125 MHz, CDCl3): δ = 159.57, 145.68, 139.93, 135.73,
135.58, 135.38, 135.19, 128.34, 128.22, 127.87, 127.75, 127.31,
127.19, 126.63, 126.57, 125.71, 125.41, 76.30, 76.04, 75.79, 19.62,
19.56, 19.35, 19.19.
Yellow oil; yield: 36 mg (72%).
IR (neat): 751, 1046, 1257, 1489, 1582, 1736, 2927 cm–1
1H NMR (500 MHz, CDCl3): δ = 8.76 (d, J = 1.6 Hz, 1 H), 8.03 (d, J = 8.4
Hz, 1 H), 7.83 (s, 1 H), 7.68 (d, J = 8.1 Hz, 1 H), 7.61 (t, J = 7.6 Hz, 1 H),
7.46 (t, J = 7.4 Hz, 1 H), 7.19 (dd, J = 12.7, 4.7 Hz, 1 H), 6.77 (d, J = 7.5
Hz, 1 H), 6.75–6.70 (m, 2 H), 4.08 (s, 2 H), 3.72 (s, 3 H).
.
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2015, 47, 976–984

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Paper
Synthesis
Supporting Information
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Supporting information for this article is available online at
http://dx.doi.org/10.1055/s-0034-1380110.
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© Georg Thieme Verlag Stuttgart · New York — Synthesis 2015, 47, 976–984