Iron oxide-silver magnetic nanoparticles as simple heterogeneous catalysts for the direct inter/intramolecular nucleophilic substitution of π-activated alcohols with electron-deficient amines

Article abstract of DOI:10.1016/j.tet.2015.06.028

The development of bimetallic iron oxide-silver magnetic nanoparticles (Fe₂O₃-Ag MNPs) catalytic system provides an efficient heterogeneous synthetic pathway to allylic amines and 1,2-dihydroquinolines involving the direct inter/intramolecular nucleophilic substitution of π-activated alcohols with electron-deficient amines. The major advantages of the present method are wide substrate scope, simple product separation, low catalyst loading, and magnetically recyclable catalyst.

Full text of DOI:10.1016/j.tet.2015.06.028

Tetrahedron xxx (2015) 1e6
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Tetrahedron
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Iron oxide-silver magnetic nanoparticles as simple heterogeneous
catalysts for the direct inter/intramolecular nucleophilic
substitution of
p
-activated alcohols with electron-deficient amines
*
Xingzhu Xu, Haibo Wu, Zhengyi Li, Xiaoqiang Sun, Zhiming Wang
Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, School of Petrochemical Engineering, Changzhou University, Changzhou,
Jiangsu 213164, China
a r t i c l e i n f o
a b s t r a c t
Article history:
The development of bimetallic iron oxide-silver magnetic nanoparticles (Fe2O3eAg MNPs) catalytic
system provides an efficient heterogeneous synthetic pathway to allylic amines and 1,2-
Received 21 March 2015
Received in revised form 4 June 2015
Accepted 6 June 2015
Available online xxx
dihydroquinolines involving the direct inter/intramolecular nucleophilic substitution of
p-activated al-
cohols with electron-deficient amines. The major advantages of the present method are wide substrate
scope, simple product separation, low catalyst loading, and magnetically recyclable catalyst.
Ó 2015 Elsevier Ltd. All rights reserved.
Keywords:
Iron oxide
Silver
Allylic amine
1,2-Dihydroquinoline
1. Introduction
indolines, and etc.9 Despite the impressive progress, some exam-
ples suffer from the limitation of expensive or toxic catalysts, un-
Allylic amines are valuable intermediates in synthetic strategies
to bioactive natural products and pharmaceutically interesting
compounds,1 and also are useful substrates involved ring-closing
alkene metathesis2 and asymmetric isomerization.3 Among the
various synthetic methodologies for allylated nitrogen com-
pounds,4,5 the direct catalytic nucleophilic substitution reactions of
desirable regioselectivities, high temperatures, and complicated
catalyst recovery. In this regard, the development of efficient, easily
recoverable and recyclable catalysts for the direct nucleophilic
substitution of p-activated alcohols is still highly desired.
In recent years, magnetic nanoparticles (MNPs) have attracted
a great attention as promising catalyst supports because of their
facile separation by magnetic force, easy preparation and modifi-
cation, high surface area-to-volume ratio, as well as low toxicity
and cost.10 Various MNP supported catalysts have been designed
and widely used in different kinds of organic reactions, such as
coupling reactions, hydrogenation, oxidation, organocatalysis,
biocatalysis, and etc.10,11 In particular, MNPs with precious metals
such as gold, palladium, or ruthenium provide very useful bi-
metallic MNPs with high catalytic activities for transition metal-
catalyzed reactions. For example, the dumbbell-like gold-coated
Fe3O4 nanoparticles show superior catalytic activities than either
Au or Fe3O4 nanoparticles in H2O2 oxidation, which was reported
by Sun and co-workers in 2010.12 Surprisingly, compared with the
extensive studies of other noble metals MNPs, the research on sil-
ver MNPs using as magnetically recyclable catalyst is relatively
limited,13,14 although the silver as a traditional catalyst is widely
used in organic synthesis. Furthermore, there are no reports on the
use of silver based MNPs as magnetically recyclable catalyst for the
p-activated alcohols with azo compounds such as amines and
amides is one of the most efficient and desirable methods in the
context of ‘Green Chemistry’.6 The main merits of this trans-
formation are high atom efficiency and producing water as the only
by-product by using allylic alcohols rather than their derivatives,
such as allylic esters or carbonates, as the starting materials. In
2002, Ozawa group firstly reported an efficient Pd-catalyzed direct
conversion of allylic alcohols into allylation products in the absence
of activating agents under mild reaction conditions.7 Since then, the
protocols with different kinds of nitrogen nucleophiles have been
discovered applying various Lewis acids or Brønsted acids as the
catalysts.8 Moreover, the Lewis acid-catalyzed intramolecular al-
lylic aminations of free p-activated alcohols turn out to be a facile
and efficient pathway to synthesize nitrogen-containing hetero-
cycles, such as dihydroquinolines, quinolines, piperidines,
* Corresponding author. Tel./fax: þ86 51986330257; e-mail addresses:
direct nucleophilic substitution of
p-activated alcohols with
wzmmol@hotmail.com, zhiming@cczu.edu.cn (Z. Wang).
http://dx.doi.org/10.1016/j.tet.2015.06.028
0040-4020/Ó 2015 Elsevier Ltd. All rights reserved.
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2
X. Xu et al. / Tetrahedron xxx (2015) 1e6
Table 1
electron-deficient amines. During the course of our ongoing study
on the development of nitrogen-containing compound forma-
tions,15 herein, we would like to report a facile and efficient syn-
thetic pathway to allylic amines and 1,2-dihydroquinolines
involving the direct inter/intramolecular nucleophilic substitution
Optimization of reaction conditionsa
of
p-activated alcohols with electron-deficient amines by using
Entry
Catalyst (loading)
None
Solvent
Time (h)
Yield (%)b
Fe2O3eAg MNPs as simple and recyclable heterogeneous catalysts.
1
2
3
4
Toluene
Toluene
Toluene
Toluene
24
24
18
18
Tracec
Tracec
48
g
-Fe2O3 NMPs (3 mol %)d
Ag NPs (3 mol %)e
2. Results and discussion
g
-Fe2O3 NMPs (3 mol %)þAg
53
NPs (3 mol %)
5
6
7
8
Fe2O3eAg NMPs (0.5 mol %)
Fe2O3eAg NMPs (2 mol %)
Fe2O3eAg NMPs (3 mol %)
Fe2O3eAg NMPs (5 mol %)
Fe2O3eAg NMPs (3 mol %)
Fe2O3eAg NMPs (3 mol %)
Fe2O3eAg NMPs (3 mol %)
Fe2O3eAg NMPs (3 mol %)
Fe2O3eAg NMPs (3 mol %)
Toluene
Toluene
Toluene
Toluene
Benzene
DMFf
10
10
10
10
48
48
48
10
10
82
84
93
92
75
70
72
The Fe2O3eAg MNPs catalyst was prepared according to the
procedure shown in Scheme 1. The synthetic method used was
adapted from the reported literatures.11g,16,17 As illustrated in
Scheme 1, Fe MNPs were prepared by NaBH4 reduction of FeSO4 and
the silver decorated iron MNPs (Fe2O3eAg MNPs) were obtained
through the FeeAg replacement reaction, followed by drying at
60 ꢀC in an oven. The nanocatalyst obtained above was well char-
acterized by X-ray diffraction (XRD), X-ray photoelectron spectros-
copy (XPS), transmission electron microscopy (TEM), atomic
absorption spectroscopy (AAS), and vibrating sample magnetome-
ter (VSM).18 Interestingly, the XRD data clearly shows that the
composition of the catalyst (Fe2O3eAg MNPs) is Ag (0) deposited
9
10
11
12
13
DMSOf
CH2CI2
THF
Tracec
Tracec
a
0.5 mmol of 1a, 0.6 mmol of 2a, catalyst, and 2 mL of solvent under reflux.
Isolated yields obtained by flash chromatography on silica gel.
Less than 5% of 3a was obtained and more than 90% of 1a was recovered.
20 nm purchased from Aladdin Reagent.
20e40 nm purchased from Sigma Aldrich.
At 110 ꢀC.
b
c
d
e
f
onto g-Fe2O3 surface, and no Fe (0) peak can be found (Fig. S1). The
XPS analysis of Ag3d and Fe2p spectra further conform the existence
of Ag (0) and Fe (III) in our FeeAg MNPs (Fig. S4 and S5). These
suggest that the bare Fe (0) MNPs obtained from NaBH4 reduction
are totally oxidized by air during the further treatment after the
FeeAg replacement reaction. The crystallite size of the Fe2O3eAg
MNPs obtained using the Debye-Scherrer equation, on the basis of
the (311) line from the XRD, was found to be 14.5 nm, and in
agreement with the result observed from the TEM, which shows
a size distribution between 10 and 20 nm (Fig. S6). Moreover, the
catalyst’s weight percentage of Ag was determined to be 5.8% by AAS
analysis.16b The magnetic properties of as-prepared Fe2O3eAg MNPs
was investigated by VSM at room temperature (Fig. S7). Although
the saturated magnetization (Ms) value of the Fe2O3eAg MNPs is less
direct substitution reaction took place in benzene, DMSO, or DMF
with moderate yields (entries 9e11), and only little desired product
could be detected in CH2Cl2 or THF (entries 12 and 13). Moreover,
the bimetallic catalyst Fe2O3eAg MNPs could be recovered and
reused up to five times with no appreciable decrease in yield (Table
S2).18 At the same time, we note no detectable differences of the
catalyst by XPS (Fig. S2eS5) and TEM (Fig. S6). These suggest that
the Ag species are strongly attached to the surface of magnetite
through van der Waal forces and etc.
With the optimized reaction conditions in hand, the reaction
scope was explored with a variety of
p-activated alcohols and
electron-deficient amines. The results were summarized in Table 2.
The electron-deficient amines, such as p-toluenesulfonamide,
methylsulfonamide, pyrimidin-2-amine, benzamide, and acetamide,
reacted well with the (E)-1,3-diphenylprop-2-en-1-ol under stan-
dard reaction condition (3a, 3b, and 3ee3g). When (E)-1,3-arylprop-
2-en-1-ols with methoxyl, chloro, or methyl groups as the sub-
stituents on the aromatic rings were used, the corresponding prod-
ucts were achieved with good to excellent yields (3i, 3l, and 3m). To
expand the reaction scope, the unsymmetrical (E)-1,3-arylprop-2-
en-1-ols were further examined and the expected products were
obtained with poor regioselectivities according to the 1H NMR and
13C NMR (3n and 3o). It seems clear that the regioisomers (3nb and
3ob) were produced through allylic carbocation rearrangement, thus
supporting the mechanism of the current substitution reaction in-
volved an SN1 pathway, which is quite different from either a bor-
rowing hydrogen or an SN2 pathway by using alumina-entrapped
than that of commercially available g-Fe2O3 MNPs probably due to
the existence of Ag (Table S1), fortunately, the magnetism of the
Fe2O3eAg MNPs was still strong enough to be separated easily from
the reaction system under an external magnetic field (Fig. S8).
Scheme 1. Synthesis of Fe2O3eAg MNPs.
In order to test the activity of the prepared catalyst as described
above, the direct nucleophilic substitution between (E)-1,3-
diphenylprop-2-en-1-ol (1a) and p-toluenesulfonamide (2a) was
chosen as the model reaction and a brief screening of the reaction
conditions was undertaken (Table 1). Although (E)-N-(1,3-
diphenyl- allyl)-4-methylbenzenesulfonamide (3a) was barely
detected in the absence of metal catalyst, a reaction yield of 93%
was obtained in the present of 3 mol % of bimetallic catalyst
Ag19 or iron/amino acid20 as catalyst. Furthermore, other
p-acti-
vated alcohols, such as (E)-4-phenylbut-3-en-3-ol, 1-phenylethanol,
diphenylmethanol, cyclohex-2-enol, and 1-(fura-2-yl)ethanol also
worked well for this transformation (3c, 3d, 3h, 3k, and 3q), and the
use of xylene as a solvent instead of toluene could improve the re-
action efficiency in some cases (3h and 3k). Interestingly, when 1-
phenylpro-2-en-1-ol and (E)-3-phenylprop-2-en-1-ol were applied
as the substrates, the same product 3j or 3p was detected. It seems
that the regioselectivity of the substitutions is controlled by the
steric hindrance of allylic carbocation. When (R)-1-phenylethanol
was used as the starting material, the 4-methyl-N-(1-phenylethyl)
benzenesulfonamide 3d was obtained in 54% as a racemic mixture,
and no chirality transfer was observed. These results also suggest
that the Fe2O3eAg MNPs catalyzed nucleophilic substitution re-
action goes through an SN1 pathway.
Fe2O3eAg MNPs in toluene (entries 1 and 7). Compared with g-
Fe2O3 and Ag NPs, the catalyst Fe2O3eAg MNPs was essential or
more efficient for the substitution reaction (entries 2e8). The major
factor determined the difference between entry 3 and entry 7 may
be the nanoparticle size of the catalysts because both the activity
and the selectivity of the catalysts usually increase with decreasing
size of the catalyst bodies according to the literatures.10a,10g It was
noteworthy that lowing the catalyst loading to 0.5 or 2 mol % could
also get reasonable reaction yields (entries 5 and 6), however, in-
creasing the catalyst loading to 5 mol % could not benefit the re-
action time or yield (entry 8). Among the solvents screened, the
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X. Xu et al. / Tetrahedron xxx (2015) 1e6
3
Table 2
Table 3
Fe2O3eAg MNPs catalyzed intermolecular nucleophilic substitutions with a variety
Fe2O3eAg MNPs catalyzed intramolecular nucleophilic substitutions for the syn-
of alcohols and aminesa,b
thesis of 1,2-dihydroquinilinesa,b
9c
heterogeneous catalytic system is even higher than that in AuCl3
15a
or FeCl3
homogeneous catalytic system.
3. Conclusions
In summary, we have developed a facile and efficient method-
ology for the direct inter/intramolecular nucleophilic substitution
reaction between
p-activated alcohols and electron-deficient
amines catalyzed by Fe2O3eAg MNPs, achieving the correspond-
ing allylic amines and 1,2-dihydroquinolines in yields up to 98%.
The wide substrate scope, simple product separation, low catalyst
loading, and magnetically recyclable catalyst make this protocol
attractive to the chemistry community.
4. Experimental section
4.1. Preparation of Fe2O3eAg MNPs
Encouraged by the results described above, we decided to ap-
ply this new catalytic system to the intramolecular nucleophilic
substitution reaction for the synthesis of 1,2-dihydroquinolines.
Under the same reaction condition, a number of desired products
were also obtained in good to excellent yields, and the represen-
tative results were summarized in Table 3. When (E)-1-phenyl-3-
(2-tosylaminophenyl)prop-1-en-3- ol was used as the substrate,
the intramolecular nucleophilic substitution took place smoothly
under Fe2O3eAg MNPs catalyzed reaction condition, affording the
expected product 5a with 89% yield. Based on the results of the
control experiments, it was found that the catalyst Fe2O3eAg
MNPs was essential or more efficient for the intramolecular sub-
stitution reaction (Table 3, 5a). The Fe2O3eAg MNPs catalyzed
synthesis of substituted dihydroquinolines could tolerate a methyl
group, CeCl bond, and CeBr bond at the terminal position of the
allylic alcohol moiety, providing 5b, 5d, 5g, and 5h with 77e89%
yields. Surprisingly, 4-methyl and 4-phenyl substituted 1,2-
dihydroquinolines 5c, 5e, and 5f were achieved by using the
standard catalyzed condition with very high reaction yields. In
these cases, the reaction efficiency in Fe2O3eAg MNPs
To a solution of 2.0 g FeSO4 in MeOHeH2O (30 mL/70 mL) was
added dropwise aqueous NaBH4 (0.4 g in 10 mL H2O) for 30 min
under ultrasound at pH 6 (achieved by addition of 5 N NaOH). The
obtained Fe MNPs were washed by H2O for five times. Then
aqueous AgNO3 (1.0 mL in H2O, 0.5 N) was added dropwise for
5 min to the sonicating solution of the obtained Fe MNPs in
20 mL H2O. The reaction mixture was left to sonicate for 20 min
after addition of AgNO3. The Fe2O3eAg MNPs were obtained after
washed by H2O for three times and dried for 2 h at 60 ꢀC in an oven
before being used for catalysis.
4.2. General procedure for the direct nucleophilic sub-
stitutions of
p-activated alcohols and electron-deficient
amines catalyzed by Fe2O3eAg MNPs
To a solution of alcohol (0.5 mmol) and amine (0.6 mmol) in
toluene (2 mL) was added Fe2O3eAg MNPs (28 mg). The reaction
mixture was stirred under reflux at nitrogen atmosphere until
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4
X. Xu et al. / Tetrahedron xxx (2015) 1e6
the substrate alcohol was consumed (TLC monitored). The
Fe2O3eAg MNPs was magnetically separated, and washed with
acetone (2.0 mL X 3) and H2O (2.0 mL X 3), then dried, and could
be used directly for the next run. The reaction supernatant and
acetone washings were collected together, evaporated, and pu-
rified by flash column chromatography on silica gel (petroleum
ether/ethyl acetate) to give the desired product (3ae3o and
5ae5h).
3H); 13C NMR (75 MHz, CDCl3):
129.5, 137.4, 140.6, 143.3.
d 21.6, 61.4, 127.3, 127.5, 127.7, 128.7,
4 . 2 . 9 . ( E ) - N - ( 1, 3 - b i s ( 4 - M e t h o x y p h e n y l ) a l l y l ) - 4 -
methylbenzenesulfonamide (3i). White solid; mp 124e125 ꢀC; 98%
yield; 1H NMR (300 MHz, CDCl3):
d
7.64 (d, J¼8.1 Hz, 2H), 7.25e7.08
(m, 6H), 6.79e6.74 (m, 4H), 6.26 (d, J¼15.9 Hz, 1H), 5.91 (dd, J¼6.6,
16.5 Hz, 1H), 5.11e5.00 (m, 2H), 3.78 (s, 3H), 3.75 (s, 3H), 2.32 (s,
3H); 13C NMR (75 MHz, CDCl3):
d 21.5, 55.4, 59.4, 113.9, 114.0, 126.3,
4.2.1. (E)-N-(1,3-Diphenylallyl)-4-methylbenzenesulfonamide
127.4, 127.8, 128.4, 129.0, 129.5, 131.4, 132.1, 137.9, 143.2, 159.2,
159.4; HRMS (EI): m/z calcd for C24H25NO4S (Mþ): 423.1504, Found,
423.1509.
(3a).15b Light yellow solid; mp 137e139 ꢀC (lit.15b 133e135 ꢀC); 93%
yield; 1H NMR (300 MHz, CDCl3):
d
7.67 (d, J¼8.4 Hz, 2H), 7.31e7.15
(m, 12H), 6.36 (d, J¼15.9 Hz, 1H), 6.09 (dd, J¼6.6, 15.9 Hz, 1H),
5.16e5.07 (m, 2H), 2.34 (s, 3H); 13C NMR (75 MHz, CDCl3):
21.4,
d
4.2.10. N-Cinnamyl-4-methylbenzenesulfonamide (3j).8f Light yel-
low solid; mp 104e106 ꢀC (lit.22 103e105 ꢀC); 62% yield; 1H NMR
59.8, 126.5, 127.1, 127.3, 127.8, 127.9, 128.2, 128.5, 128.7, 129.5, 132.2,
136.0, 137.7, 139.7, 143.3.
(300 MHz, CDCl3):
d
7.78 (d, J¼8.4 Hz, 2H), 7.33e7.23 (m, 7H), 6.44
(d, J¼15.9 Hz, 1H), 6.02 (td, J¼6.3, 15.9 Hz, 1H), 4.48 (br, 1H), 3.76
4.2.2. (E)-N-(1,3-Diphenylallyl)methanesulfonamide
yellow solid; mp 125e127 ꢀC (lit.8h 127 ꢀC); 84% yield; 1H NMR
(300 MHz, CDCl3):
7.41e7.24 (m, 10H), 6.63 (d, J¼15.6 Hz,1H), 6.33
(dd, J¼6.6,15.6 Hz,1H), 5.31e5.27 (m,1H), 4.89 (br,1H), 2.79 (s, 3H);
13C NMR (75 MHz, CDCl3):
42.3, 59.9, 126.8, 127.3, 128.3, 128.4,
(3b).8h Light
(dt, J¼1.5, 7.8 Hz, 2H), 2.42 (s, 3H); 13C NMR (75 MHz, CDCl3):
d
21.7, 45.7, 124.2, 126.6, 127.4, 128.1, 128.7, 129.9, 133.3, 136.2,
d
137.2, 143.7.
d
4.2.11. N-(Cyclohex-2-en-1-yl)-4-methylbenzenesulfonamide
128.5, 128.8, 129.2, 132.6, 136.0, 134.0.
(3k).8d White solid; mp 101e102 ꢀC (lit.8d 102e103 ꢀC); 72% yield;
1H NMR (300 MHz, CDCl3):
d
7.77 (d, J¼7.8 Hz, 2H), 7.30 (d, J¼7.8 Hz,
4.2.3. (E)-4-Methyl-N-(4-phenylbut-3-en-2-yl)benzenesulfonamide
2H), 5.80e5.73 (m, 1H), 5.37e5.31 (m, 1H), 4.46 (d, J¼8.4 Hz, 1H),
(3c).8d White solid; mp 90e92 ꢀC (lit.8d 88e89 ꢀC); 72% yield; 1H
3.85e3.78 (br, 1H), 2.43 (s, 3H), 1.96e1.90 (m, 2H), 1.80e1.72 (m,
NMR (300 MHz, CDCl3):
d
7.76 (d, J¼8.4 Hz, 2H), 7.28e7.12 (m, 7H),
1H), 1.64e1.51 (m, 3H); 13C NMR (75 MHz, CDCl3):
d 19.4, 21.7, 24.6,
6.28 (d, J¼16.2 Hz, 1H), 5.83 (dd, J¼6.9, 15.6 Hz, 1H), 4.91e4.87 (br,
30.4, 49.1, 127.1, 127.2, 129.8, 131.8, 138.5, 143.4.
1H), 4.11e4.04 (m, 1H), 2.33 (s, 3H), 1.26 (d, J¼6.6 Hz, 3H); 13C NMR
(75 MHz, CDCl3):
d
21.6, 22.0, 51.8, 126.5, 127.4, 127.8, 128.5, 129.7,
4 . 2 . 1 2 . ( E ) - N - ( 1, 3 - b i s ( 4 - C h l o r o p h e n y l ) a l l y l ) - 4 -
130.2, 130.6, 136.4, 138.1, 143.4.
methylbenzenesulfonamide (3l). White solid; mp 137e139 ꢀC; 80%
yield; 1H NMR (300 MHz, CDCl3):
d
7.62 (d, J¼8.4 Hz, 2H), 7.32e7.09
4.2.4. 4-Methyl-N-(1-phenylethyl)benzenesulfonamide
(m, 10H), 6.29 (d, J¼15.6 Hz, 1H), 6.02 (dd, J¼6.6, 15.9 Hz, 1H), 5.08
(3d).8a White solid; mp 82e84 ꢀC (lit.8a 81e82 ꢀC); 50% yield;
(t, J¼6.9 Hz, 1H), 5.00 (d, J¼6.9 Hz, 1H), 2.36 (s, 3H); 13C NMR
1H NMR (300 MHz, CDCl3):
d
7.61 (d, J¼8.4 Hz, 2H), 7.19e7.16
(75 MHz, CDCl3): d 21.6, 59.2, 127.4, 127.9, 128.4, 128.6, 128.9, 129.0,
(m, 5H), 7.10e7.08 (m, 2H), 5.06 (br, 1H), 4.48e4.43 (m, 1H),
2.38 (s, 3H), 1.41 (d, J¼6.9 Hz, 3H); 13C NMR (75 MHz, CDCl3):
129.7, 131.5, 133.9, 134.0, 134.4, 137.6, 137.9, 143.7; HRMS (EI): m/z
calcd for C22H19Cl2NO2S (Mþ): 431.0514, Found, 431.0512.
d
21.6, 23.7, 53.8, 126.2, 127.2, 127.6, 128.6, 129.6, 137.7, 142.2,
143.2.
4.2.13. (E)-N-(1,3-di-p-Tolylallyl)-4-methylbenzenesulfonamide
(3m).21 White solid; mp 128e130 ꢀC; 82% yield; 1H NMR (300 MHz,
4.2.5. (E)-N-(1,3-Diphenylallyl)pyrimidin-2-amine
(3e).15b Light
8.26 (d, J¼4.8 Hz,
CDCl3):
d
7.71 (d, J¼8.1 Hz, 2H), 7.17e7.06 (m, 10H), 6.33 (dd, J¼0.6,
yellow oil; 74% yield; 1H NMR (300 MHz, CDCl3):
d
15.9 Hz, 1H), 6.06 (dd, J¼6.9, 15.9 Hz, 1H), 5.48e5.46 (br, 1H), 5.10 (t,
2H), 7.45e7.19 (m, 10H), 6.63 (d, J¼15.6 Hz, 1H), 6.53 (t, J¼4.8 Hz,
J¼7.2 Hz, 1H), 2.35 (s, 6H), 2.33 (s, 3H); 13C NMR (75 MHz, CDCl3):
1H), 6.44 (dd, J¼5.4, 15.9 Hz, 1H), 5.96e5.87 (m, 2H); 13C NMR
d
21.1, 21.2, 21.4, 59.7, 126.5, 127.0, 127.3, 127.4, 129.2, 129.3, 129.4,
(75 MHz, CDCl3):
d
56.7, 111.2, 126.7, 127.3, 127.6, 127.8, 128.7, 128.8,
131.7, 133.5, 136.9, 137.4, 137.6, 137.9, 143.1.
130.0, 130.8, 136.8, 141.7, 158.2, 161.7.
4.2.14. N-Cinnamylmethanesulfonamide (3p).23 White solid; mp
73e75 ꢀC (lit.23 74e76 ꢀC); 65% yield; 1H NMR (300 MHz, CDCl3):
4.2.6. (E)-N-(1,3-Diphenylallyl)benzamide (3f).15b Light yellow
solid; mp 156e158 ꢀC (lit.15b 150e152 ꢀC); 93% yield; 1H NMR
d
7.39e7.25 (m, 5H), 6.61 (d, J¼15.9 Hz, 1H), 6.20 (dt, J¼15.9,
(300 MHz, CDCl3):
6.63 (d, J¼16.8 Hz, 1H), 6.51e6.42 (m, 2H), 6.03 (t, J¼6.6 Hz,
1H); 13C NMR (75 MHz, CDCl3):
55.4, 126.7, 127.2, 127.4, 127.9,
d
7.85e7.82 (m, 2H), 7.55e7.24 (m, 13H),
6.3 Hz, 1H), 4.63 (br, 1H), 3.93 (td, J¼6.3, 1.5 Hz, 2H), 2.99 (s, 3H);
13C NMR (75 MHz, CDCl3):
133.4, 136.0.
d 41.2, 45.4, 124.4, 126.5, 128.2, 128.7,
d
128.0, 128.7, 128.8, 128.9, 129.0, 131.8, 131.9, 134.4, 136.5, 140.9,
166.6.
4.2.15. N-(1-(Furan-2-yl)ethyl)-4-methylbenzenesulfonamide
(3p).24 White solid; mp 72e73 ꢀC (lit.24 72e73 ꢀC); 63% yield; 1H
4.2.7. (E)-N-(1,3-Diphenylallyl)acetamide (3g).8e White solid; mp
135e136 ꢀC (lit.8e 136e138 ꢀC); 72% yield; 1H NMR (300 MHz,
NMR (300 MHz, CDCl3):
d
7.68 (d, J¼8.4 Hz, 2H), 7.23 (d,
J¼8.4 Hz, 2H), 7.16 (dd, J¼1.8, 0.9 Hz, 1H), 6.15 (dd, J¼3.3, 2.1 Hz,
1H), 5.98 (dd, J¼3.0, 0.6 Hz, 1H), 5.10 (d, J¼8.1 Hz, 1H), 4.59e4.49
(m, 1H), 2.40 (s, 3H), 1.44 (d, J¼6.9 Hz, 3H); 13C NMR (75 MHz,
CDCl3):
15.9 Hz, 1H), 5.84e5.82 (m, 2H), 2.07 (s, 3H); 13C NMR (75 MHz,
CDCl3): 23.7, 54.9, 126.7, 127.4, 127.9, 128.0, 128.7, 129.0, 131.5,
d
7.35e7.24 (m, 10H), 6.54 (d, J¼15.9 Hz, 1H), 6.34 (dd, J¼5.7,
d
CDCl3): d 21.9, 21.5, 47.4, 106.1, 110.1, 127.0, 129.5, 137.7, 141.9,
136.6, 141.0, 169.2.
143.1, 154.1.
4.2.8. N-Benzhydryl-4-methylbenzenesulfonamide
(3h).8a White
4.2.16. 2-Phenyl-1-tosyl-1,2-dihydroquinoline (5a).9c White solid;
mp 124e126 ꢀC (lit.25 125 ꢀC); 89% yield; 1H NMR (400 MHz,
solid; mp 157e159 ꢀC (lit.8a 156e158 ꢀC); 72% yield; 1H NMR
(300 MHz, CDCl3):
7.11e7.07 (m, 6H), 5.56 (d, J¼7.2 Hz, 1H), 5.30e5.23 (br, 1H), 2.37 (s,
d
7.55 (d, J¼8.4 Hz, 2H), 7.24e7.16 (m, 6H),
CDCl3):
d
7.64 (d, J¼8.0 Hz, 1H), 7.34e7.33 (m, 4H), 7.24e7.18 (m,
4H), 7.14e7.08 (m, 3H), 6.96 (d, J¼7.2 Hz, 1H), 6.28 (d, J¼9.6 Hz, 1H),
Please cite this article in press as: Xu, X.; et al., Tetrahedron (2015), http://dx.doi.org/10.1016/j.tet.2015.06.028

X. Xu et al. / Tetrahedron xxx (2015) 1e6
5
6.02 (d, J¼6.0 Hz, 1H), 5.88 (dd, J¼9.6, 6.0 Hz, 1H), 2.35 (s, 3H); 13
C
d 21.6, 56.3,122.0,125.8,126.0,126.4,126.7,127.2,127.6,128.4,128.5,
129.1, 129.2, 131.5, 132.6, 135.9, 137.4, 143.6.
NMR (125 MHz, CDCl3):
d
21.5, 57.0, 125.5, 126.3, 126.4, 126.5, 127.2,
127.4, 127.6, 127.9, 128.2, 128.4, 128.6, 129.1, 132.9, 136.1, 138.4,
143.4.
Acknowledgements
4.2.17. 2-(p-Tolyl)-1-tosyl-1,2-dihydroquinoline (5b).9c White solid;
mp 123e125 ꢀC (lit.9c 124e127 ꢀC); 87% yield; 1H NMR (400 MHz,
This work was financially supported by the Natural Science
Foundation of China (Grant no. 21372033), the Priority Academic
Program Development of Jiangsu Higher Education Institutions,
Jiangsu Key Laboratory of Advanced Catalytic Materials and Tech-
nology (BM2012110), the Qing Lan Project, and the National Natural
Science Foundation of Jiangsu Province (Grant no. 12KYB150002
and no. 14KJA150002).
CDCl3):
d
7.63 (d, J¼8.0 Hz, 1H), 7.33 (d, J¼8.0 Hz, 2H), 7.23e7.18
(m, 3H), 7.14e7.08 (m, 3H), 7.04 (d, J¼8.0 Hz, 2H), 6.96 (d,
J¼7.6 Hz, 1H), 6.26 (d, J¼9.6 Hz, 1H), 5.98 (d, J¼6.0 Hz, 1H), 5.87
(dd, J¼9.6, 6.0 Hz, 1H), 2.35 (s, 3H), 2.26 (s, 3H); 13C NMR
(125 MHz, CDCl3):
d 21.1, 21.6, 56.8, 125.4, 126.2, 126.4, 126.7,
127.3, 127.4, 127.7, 128.2, 128.7, 129.1, 129.2, 132.9, 135.3, 136.2,
137.7, 143.3.
Supplementary data
4.2.18. 4-Methyl-1-tosyl-1,2-dihydroquinoline (5c).9c White solid;
mp 80e82 ꢀC (lit.26 82 ꢀC); 98% yield; 1H NMR (400 MHz, CDCl3):
Supplementary data (Copies of the 1H NMR and 13C NMR spectra
of all key intermediates and final products) associated with this
article can be found in the online version, at http://dx.doi.org/
10.1016/j.tet.2015.06.028. These data include MOL files and InChi-
Keys of the most important compounds described in this article.
d
7.70 (d, J¼8.0 Hz,1H), 7.32e7.28 (m,1H), 7.26e7.16 (m, 3H), 7.11 (d,
J¼7.6 Hz, 1H), 7.05 (d, J¼8.0 Hz, 2H), 5.32 (br, 1H), 4.34e4.33 (m,
2H), 2.33 (s, 3H),1.58 (s, 3H); 13C NMR (125 MHz, CDCl3):
17.7, 21.4,
d
45.3, 120.3, 123.3, 126.7, 127.2, 127.4, 127.8, 128.8, 131.4, 131.6, 135.2,
136.1, 143.2.
References and notes
4.2.19. 2-(2-Chlorophenyl)-1-tosyl-1,2-dihydroquinoline
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Wiley-VCH: New York, NY, 2000.
4. For selected reviews on allylic amine synthesis, see: (a) Breder, A. Synlett 2014,
899e904; (b) Ramirez, T. A.; Zhao, B.; Shi, Y. Chem. Soc. Rev. 2012, 41, 931e942;
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M.; Jørgensen, K. A. Chem. Rev. 1998, 98, 1689e1708.
(5d).15a White solid; mp 147e149 ꢀC; 89% yield; 1H NMR (400 MHz,
CDCl3):
d
7.79 (d, J¼8.0 Hz, 1H), 7.39e7.34 (m, 3H), 7.30 (t, J¼7.6 Hz,
1H), 7.18e7.09 (m, 5H), 7.01 (t, J¼7.6 Hz, 1H), 6.95 (d, J¼7.6 Hz, 1H),
6.45 (d, J¼5.6 Hz, 1H), 6.15 (d, J¼9.6 Hz, 1H), 6.01 (dd, J¼9.6, 5.6 Hz,
1H), 2.35 (s, 3H); 13C NMR (125 MHz, CDCl3):
d 21.6, 55.2, 124.6,
126.0, 126.5, 126.6, 127.1, 127.5, 128.1, 128.3, 128.6, 129.0, 129.1,
129.9, 131.3, 134.0, 135.8, 137.3, 143.6.
5. For recent selected examples on allylic amine synthesis, see: (a) Kawatsura, M.;
Terasaki, S.; Minakawa, M.; Hirakawa, T.; Ikeda, K.; Itoh, T. Org. Lett. 2014, 16,
2442e2445; (b) Lee, J. H.; Lee, S. Chem. Sci. 2013, 4, 2922e2927; (c) Beck, J. F.;
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4.2.20. 6-Chloro-4-phenyl-1-tosyl-1,2-dihydroquinoline
(5e).9c White solid; mp 168e170 ꢀC (lit.9c 167e170 ꢀC); 98% yield;
1H NMR (300 MHz, CDCl3):
d
7.73 (d, J¼8.8 Hz,1H), 7.34 (d, J¼8.4 Hz,
2H), 7.31e7.23 (m, 4H), 7.06 (d, J¼7.8 Hz, 2H), 6.84 (d, J¼2.4 Hz, 1H),
6.71e6.68 (m, 2H), 5.61 (t, J¼4.5 Hz, 1H), 4.53 (d, J¼4.5 Hz, 2H), 2.28
~
Org. Biomol. Chem. 2013, 11, 7076e7079; (f) Souto, J. A.; Zian, D.; Muniz, K. J. Am.
Chem. Soc. 2012, 134, 7242e7245; (g) Xie, Y.; Hu, J.; Wang, Y.; Xia, C.; Huang, H.
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L.; Tu, S. J.; Li, G. J. Org. Chem. 2012, 77, 7497e7505.
(s, 3H); 13C NMR (75 MHz, CDCl3):
d 21.4, 45.4, 122.9, 125.8, 127.5,
127.9, 128.1, 128.2, 128.4, 129.0, 129.2, 132.3, 132.4, 134.0, 135.8,
137.3, 137.9, 143.7.
6. For recent reviews on nucleophilic substitution reactions of
p-activated alco-
hols with nitrogenated compounds, see: (a) Muzart, J. Eur. J. Org. Chem. 2007,
3077e3089; (b) Muzart, J. Tetrahedron 2008, 64, 5815e5849; (c) Emer, E.; Sinisi,
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Chem. 2011, 647e666; (d) Bandini, M. Angew. Chem., Int. Ed. 2011, 50, 994e995;
(e) Biannic, B.; Aponick, A. Eur. J. Org. Chem. 2011, 6605e6617.
4.2.21. 4-Phenyl-1-tosyl-1,2-dihydroquinoline (5f).9c White solid;
mp 128e130 ꢀC (lit.9c 129e131 ꢀC); 97% yield; 1H NMR (400 MHz,
7. Ozawa, F.; Okamoto, H.; Kawagishi, S.; Yamamoto, S.; Minami, T.; Yoshifuji, M. J.
Am. Chem. Soc. 2002, 124, 10968e10969.
CDCl3):
d
7.80 (d, J¼8.0 Hz, 1H), 7.35e7.32 (m, 3H), 7.25e7.22 (m,
3H), 7.14 (t, J¼7.6 Hz, 1H), 7.03 (d, J¼8.0 Hz, 2H), 6.87 (d, J¼7.6 Hz,
8. For recent selected examples on nucleophilic substitution reactions of
p-acti-
1H), 6.71 (d, J¼7.0 Hz, 2H), 5.58 (t, J¼4.4 Hz, 1H), 4.54 (d, J¼4.4 Hz,
vated alcohols with nitrogenated compounds, see: (a) Li, L.; Zhu, A.; Zhang, Y.;
2H), 2.27 (s, 3H); 13C NMR (125 MHz, CDCl3):
d 21.3, 45.5, 121.6,
Fan, X.; Zhang, G. RSC Adv. 2014, 4, 4286e4291; (b) Fan, G. P.; Liu, Z.; Wang, G.
ꢀ
W. Green Chem. 2013, 15, 1659e1664; (c) Trillo, P.; Baeza, A.; Najera, C. Chem-
126.0, 126.6, 127.57, 127.61, 127.64, 127.9, 128.3, 128.5, 129.1, 131.0,
135.5, 136.1, 138.1, 138.7, 143.4.
ꢀ
CatChem 2013, 5, 1538e1542; (d) Trillo, P.; Baeza, A.; Najera, C. J. Org. Chem.
2012, 77, 7344e7354; (e) Gopal Das, B.; Nallagonda, R.; Ghorai, P. J. Org. Chem.
2012, 77, 5577e5583 and references cited therein; (f) Trillo, P.; Baeza, A.;
ꢀ
Najera, C. Eur. J. Org. Chem. 2012, 2929e2934 and references cited therein; (g)
4.2.22. 2-(4-Chlorophenyl)-1-tosyl-1,2-dihydroquinoline
Han, F.; Yang, L.; Li, Z.; Xia, C. Adv. Synth. Catal. 2012, 354, 1052e1060; (h) Giner,
X.; Trillo, P.; Najera, C. J. Organomet. Chem. 2011, 696, 357e361.
(5g).9c White solid; mp 129e130 ꢀC (lit.9c 128e131 ꢀC); 77%
ꢀ
yield; 1H NMR (400 MHz, CDCl3):
d
7.64 (d, J¼8.0 Hz, 1H), 7.32
9. (a) Guerinot, A.; Serra-Muns, A.; Gnamm, C.; Bensoussan, C.; Reymond, S.;
Cossy, J. Org. Lett. 2010, 12, 1808e1811; (b) Yamamoto, H.; Ho, E.; Namba, K.;
Imagawa, H.; Nishizawa, M. Chem.dEur. J. 2010, 16, 11271e11274; (c) Ko-
thandaraman, P.; Foo, S. J.; Chan, P. W. H. J. Org. Chem. 2009, 74, 5947e5952.
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16, 3401e3427; (b) Rossi, L. M.; Costa, N. J. S.; Silva, F. P.; Wojcieszak, R. Green
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(d, J¼8.0 Hz, 2H), 7.27 (d, J¼8.0 Hz, 2H), 7.24e7.19 (m, 3H),
7.16e7.08 (m, 3H), 6.97 (d, J¼7.6 Hz, 1H), 6.28 (d, J¼9.6 Hz, 1H),
5.98 (d, J¼6.0, 1H), 5.85 (dd, J¼9.6, 6.0 Hz, 1H), 2.35 (s, 3H); 13C
NMR (125 MHz, CDCl3):
d 21.6, 56.2, 125.9, 126.0, 126.4, 126.6,
127.2, 127.6, 128.5, 128.6, 128.9, 129.2, 132.7, 133.8, 136.0, 136.9,
143.6.
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667e677; (d) Mrowczynski, R.; Nan, A.; Liebscher, J. RSC Adv. 2014, 4,
5927e5952; (e) Nasir Baig, R. B.; Varma, R. S. Chem. Commun. 2013, 752e770;
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4.2.23. 2-(4-Bromophenyl)-1-tosyl-1,2-dihydroquinoline
(5h).9c White solid; mp 152e154 ꢀC (lit.9c 154e156 ꢀC); 84% yield;
11. For recent selected examples, see: (a) Shen, C.; Xu, J.; Yu, W.; Zhang, P. Green
Chem. 2014, 16, 3007e3012; (b) Khalafi-Nezhad, A.; Nourisefat, M.; Panahi, F.
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2014, 10, 717e724; (d) Wang, D.; Etienne, L.; Echeverria, M.; Moya, S.; Astruc, D.
Chem.dEur. J. 2014, 20, 4047e4054; (e) Baig, R. B. N.; Varma, R. S. RSC Adv. 2014,
4, 6568e6572; (f) Baig, R. B. N.; Varma, R. S. Green Chem. 2013, 15, 398e417; (g)
1H NMR (400 MHz, CDCl3):
d
7.64 (d, J¼8.0 Hz,1H), 7.36 (d, J¼8.4 Hz,
2H), 7.32 (d, J¼8.0 Hz, 2H), 7.24e7.20 (m, 3H), 7.16e7.08 (m, 3H),
6.97 (d, J¼7.2 Hz, 1H), 6.29 (d, J¼9.6 Hz, 1H), 5.96 (d, J¼5.6 Hz, 1H),
5.85 (dd, J¼9.6, 5.6 Hz, 1H), 2.35 (s, 3H); 13C NMR (125 MHz, CDCl3):
Please cite this article in press as: Xu, X.; et al., Tetrahedron (2015), http://dx.doi.org/10.1016/j.tet.2015.06.028

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X. Xu et al. / Tetrahedron xxx (2015) 1e6
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