Highly efficient and reusable ionic liquids for the catalyzed hydroamination of alkenes with sulfonamides, carbamates, and carboxamides

Article abstract of DOI:10.1055/s-0029-1216825

SO₃H-Functionalized ionic liquids were found to be efficient and reusable catalysts in the hydroamination of sulfonamides, carboxamides, p-nitroaniline and carbamates with nonactivated alkenes. The hydroamination could be performed on a large scale and the acidic ionic liquid catalyst could be reused successfully. Georg Thieme Verlag Stuttgart.

Full text of DOI:10.1055/s-0029-1216825

PAPER
1969
Highly Efficient and Reusable Ionic Liquids for the Catalyzed Hydro-
amination of Alkenes with Sulfonamides, Carbamates, and Carboxamides
C
atalyze
d
Hydr
e
oamination
i
of
A
lkenes Yang,a Li-Wen Xu,*a,b Chun-Gu Xia*a
a
State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences,
and Graduate School of the Chinese Academy of Sciences, Lanzhou 730000, P. R. of China
Fax +86(931)8277088; E-mail: lyang@lzb.ac.cn; E-mail: cgxia@lzb.ac.cn
b
Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, Hangzhou Normal University,
Hangzhou 310012, P. R. of China
Received 20 January 2009; revised 25 February 2009
In recent years, ionic liquids (ILs) have attracted consid-
erable interest and been successfully used in a variety of
catalytic reactions as environmentally benign reaction
media and catalysts due to their unique properties such as
a wide liquid range, good solvating ability, tuneable polar-
ity, high thermal stability, negligible vapor pressure, and
ease of recyclability.9 Recently, advances in the field of
ionic liquids research provides another route to achieving
task-specific ionic liquids (TSILs) in which a functional
group is covalently tethered to the cation or anion of the
ionic liquid.10 When an alkane sulfonic acid group is co-
valently tethered to the IL cation, the IL would be a strong
Brønsted acid. These functionalized ionic liquids have ex-
hibited great potential in replacement of conventional ho-
mogenous and heterogeneous acidic catalysts because
they are nonvolatile, noncorrosive and immiscible with
many organic solvents.
Abstract: SO3H-Functionalized ionic liquids were found to be effi-
cient and reusable catalysts in the hydroamination of sulfonamides,
carboxamides, p-nitroaniline and carbamates with nonactivated alk-
enes. The hydroamination could be performed on a large scale and
the acidic ionic liquid catalyst could be reused successfully.
Key words: hydroamination, ionic liquid, green chemistry, alkene,
homogeneous catalysis
New C–N bond-forming processes are highly fundamen-
tal and interesting for both organic syntheses and industri-
al processes due to the importance of nitrogen-containing
molecules as fine chemicals, pharmaceuticals and useful
building blocks.1 In the existing methods for the construc-
tion of the C–N bond, the direct addition of amines to alk-
enes and alkynes, hydroamination, is rapidly increasing in
interest as a convenient and atom-economical method for
the preparation of amines, enamines and imines.2 Despite
significant efforts that have been devoted to the intermo-
lecular hydroamination of alkenes with alkylamines and
arylamines, only a few reports of the intermolecular hy-
droamination of nonactivated alkenes with weakly basic
amine nucleophiles such as sulfonamides, carbamates and
carboxamides are known.
Although some examples of the addition of amines to alk-
enes in ionic liquids were reported recently,11 to the best
of our knowledge hydroamination of amides with alkenes
catalyzed by functional ionic liquids was unknown. As
part of our studies to explore the use of existing ionic liq-
uids in chemical reactions,12 and in continuation of our
work on the construction of the C–N bond,13 we first re-
port here the hydroamination of alkenes with sulfon-
amides, carboxamides and carbamates using SO3H-
functionalized acidic ionic liquids catalysts.
Recently, efficient hydroaminations of amides and car-
bamates catalyzed by platinum(II),3 gold(I),4 copper(II),5
iron(III),6 and other metal salts7 were reported. Along
with the metal catalysts, there were some examples using
metal-free catalysts for the hydroamination of alkenes and
amides.8 Although some notable progress has been made
on the hydroamination reactions of alkenes with amides in
the past two years, there were also some drawbacks on the
reported methods, such as, using expensive and toxic met-
als, high reaction temperature, large excess amounts of
alkenes and tedious reaction procedures. Additionally,
most of the reported methods must be carried out under an
inert atmosphere. Therefore, the development of a gener-
al, efficient, green and practical catalyst for addition reac-
tions of nonactivated alkenes with sulfonamides,
carboxamides and carbamates is highly desirable.
H
N
N+
N
N+
HSO4
N+
CF3SO3
N
–
–
–
BF4
[BMIm][CF3SO3]
[HMIm][BF4]
[BMIm][HSO4]
SO3H
SO3H
N+
N
N+
–
–
CF3SO3
CF3SO3
[MBsIm][CF3SO3]
[BSPy][CF3SO3]
Figure 1 Five existing ionic liquids used in hydroamination
We initially tested the hydroamination of cyclohexene
with p-toluenesulfonamide at 85 °C in the presence of
several ionic liquids under different reaction conditions in
air. Five existing ionic liquids, that is, [HMIm][BF4],
[BMIm][HSO4], [BMIm][CF3SO3], [MBsIm][CF3SO3]
and [BSPy][CF3SO3], have been used (Figure 1). As
SYNTHESIS 2009, No. 12, pp 1969–1974
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x.
x
x
.
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0
0
9
Advanced online publication: 19.05.2009
DOI: 10.1055/s-0029-1216825; Art ID: F02509SS
© Georg Thieme Verlag Stuttgart · New York

1970
L. Yang et al.
PAPER
shown in Table 1, the ionic liquid catalyst has a signifi-
cant effect on the yield of the reaction, only a trace of hy-
droamination adduct was obtained in the presence of
[HMIm][BF4] and [BMIm][HSO4] (entries 1 and 2). Un-
der these conditions, [BSPy][CF3SO3] proved to be very
active, leading to 72% yield of N-cyclohexyl p-toluene-
sulfonamide within 24 hours (entry 5). [BMIm][CF3SO3]
and [MBsIm][CF3SO3] could also be used as catalysts to
promote the hydroamination, but their activity seems to be
inferior compared with that of [BSPy][CF3SO3] (entries 3
and 4). These results indicated that both the anion and the
acidity of the ionic liquid were very important for achiev-
ing high yield of the product.10d In view of this,
[BSPy][CF3SO3] should be a suitable catalyst for the hy-
droamination reaction. On the basis of above results, a se-
ries of solvents were also screened (entries 6–10). We
found that polar solvents such as 1,4-dioxane and acetoni-
trile tended to shut down the reacting system, whereas
nonpolar solvents such as 1,2-dichloroethane (DCE) and
toluene seemed to be ideal. Moderate yield of the hy-
droamination product was obtained when the catalyst
loading was decreased to 10% (entry 11). Increasing cat-
alyst loading resulted in no favourable improvement of
the yield (entries 12 and 13).
Table 1 Hydroamination of p-Toluenesulfonamide and Cyclohex-
ene under Different Conditionsa
catalyst
+
NH2Ts
85 °C
NHTs
Yield (%)b
trace
trace
23
Entry
1
Ionic liquid
Solvent
MePh
[HMIm][BF4]
2
[BMIm][HSO4]
[BMIm][CF3SO3]
[MBsIm][CF3SO3]
[BSPy][CF3SO3]
[BSPy][CF3SO3]
[BSPy][CF3SO3]
[BSPy][CF3SO3]
[BSPy][CF3SO3]
[BSPy][CF3SO3]
[BSPy][CF3SO3]
[BSPy][CF3SO3]
[BSPy][CF3SO3]
MePh
3
MePh
4
MePh
65
5
MePh
72
6
DCE
62
7
dioxane
CH2Cl2
MeCN
n-heptane
MePh
trace
25
8
9
trace
34
10
11c
12d
13e
42
MePh
75
To study the scope of the procedure, other alkenes with
amides were then studied, and the results are listed in
Table 2. Benzenesulfonamide (PhSO2NH2), electron-
deficient 4-nitrobenzenesulfonamide and hindered N-
methyl-4-toluenesulfonamide underwent ionic liquid
[BSPy][CF3SO3]-catalyzed hydroamination of cyclohep-
tene or cyclohexene to form the corresponding products in
moderate to good yield (entries 1–4). The hydroamination
reactions of p-toluenesulfonamide (NH2Ts) with various
vinyl arenes gave fast and high-yielding reactions under
mild reaction conditions (entries 5, 7 and 8). Interestingly,
in the presence of electron-donating groups such as p-Me,
the reactions could be carried out at room temperature
(entry 6). We also extended this reaction to other nitrogen-
containing molecules, such as 2-oxazolidinone. The reac-
tion gave good yield of the desired product under opti-
mized reaction conditions (entry 9). The addition of
various amides to the more strained norbornene furnished
the hydroamination products in excellent yields (entries
10–13), except benzamide, only affording the product in
28% yield when using dioxane as solvent [benzamide and
NsNH2 were not very soluble in toluene or 1,2-dichloro-
ethane (entry 12)]. We further extended the scope of this
methodology to 1,3-diene, both benzyl carbamate
(CbzNH2) and sulfonamides could be added to 1,3-cyclo-
hexadiene after 24 hours at 50 °C to form allylamines in
good yields (entries 14 and 15).
MePh
80
a Reaction conditions: cyclohexene (2 mmol), NH2Ts (1 mmol), ionic
liquid (0.2 mmol), solvent (2 mL), 85 °C, 24 h, sealed tube.
b Isolated yield.
c Using 0.1 mmol of ionic liquid.
d Using 0.3 mmol of ionic liquid.
e Using 1 mmol of ionic liquid.
Further studies also showed that the addition of p-nitro-
aniline to norbornene furnished the hydroamination prod-
uct in high yield under solvent-free conditions
(Scheme 1).
In order to broaden the scope of the reaction, we also
wanted to show that the reaction could be performed at
larger scales, demonstrating that acidic ionic liquid could
be suitable for a scaleup experiment. In a typical proce-
dure, into a test tube were placed [BSPy][CF3SO3] (20
mol%), NH2Ts (6 mmol), norbornene (12 mmol) and 1,2-
dichloroethane (5 mL). After sealing, the reaction mixture
was heated at 85 °C and stirred vigorously for 24 hours.
When the reaction was complete, the mixture was concen-
trated in vacuo to remove the 1,2-dichloroethane. The
crude product was then separated by simple extraction
(EtOAc–Et2O, 1:1) and purified by column chromatogra-
phy to give the pure product. We were also pleased to find
that the same addition reaction could be performed under
H
N
[BSPy][OTf] (20 mol%)
85 °C, 24 h, no solvent
+
H2N
NO2
NO2
6 mmol
3 mmol
83%
Scheme 1 Hydroamination of p-nitroaniline with norbornene
Synthesis 2009, No. 12, 1969–1974 © Thieme Stuttgart · New York

PAPER
Catalyzed Hydroamination of Alkenes
1971
solvent-free conditions, yielding the hydroamination
product in a gram scale. In addition, we obtained the prod-
uct in 96% yield even using 60 mmol of the NH2Ts
(Scheme 2).
NHTs
[BSPy][OTf] (20 mol%)
+
NH2Ts
85 °C, 24 h
12 mmol
6 mmol
no solvent: 97%
DCE as solvent: 95%
Finally, we investigated the reusability and the recycling
of the acidic ionic liquid [BSPy][CF3SO3], and found that
the catalyst could be easily recovered after completion of
the reaction and reused in subsequent recycles (Table 3).
The activity of the catalyst only showed a slight decrease
after three runs.
120 mmol
60 mmol
no solvent: 96%
Scheme 2 Hydroamination of NH2Ts with norbornene on a large
scale
Table 2 Hydroamination of Nonactivated Alkenes with Nitrogen Nucleophilesa
NHR3
[BSPy][OTf] (20 mol%)
NH2R3
+
R1
R2
R1
R2
in air
Entry
Alkene
Nucleophile
Time (h)/ Temp (°C) Solvent
Product
Yield (%)b
66
NHTs
1
NH2Ts
24/85
MePh
2
3
4
NH2Ns
36/85
34/85
28/85
MePh
MePh
MePh
52
42
54
NHTs
NHMeTs
PhSO2NH2
NMeTs
NHSO2Ph
NHTs
5
6
7
NH2Ts
NH2Ts
NH2Ts
22/45
24/r.t.
24/45
DCE
DCE
DCE
72
70
91
NHTs
NHTs
Cl
Br
Cl
Br
NHTs
8
9
NH2Ts
2-Oxac
24/45
24/85
DCE
89
79
O
O
N
MePh
NHTs
10
11
NH2Ts
24/85
24/85
DCE
DCE
96
86
NMeTs
NHMeTs
Synthesis 2009, No. 12, 1969–1974 © Thieme Stuttgart · New York

1972
L. Yang et al.
PAPER
Table 2 Hydroamination of Nonactivated Alkenes with Nitrogen Nucleophilesa (continued)
NHR3
[BSPy][OTf] (20 mol%)
NH2R3
+
R1
R2
R1
R2
in air
Entry
Alkene
Nucleophile
Time (h)/ Temp (°C) Solvent
Product
Yield (%)b
28
NHCOPh
NHNs
12
13
14
15
PhCONH2
NH2Ns
24/85
24/85
24/50
24/50
dioxane
dioxane
DCE
92
54
62
NHTs
NH2Ts
NHCbz
NH2Cbz
DCE
a Reaction conditions: alkene (2 mmol), NH2Ts (1 mmol), [BSPy][CF3SO3] (0.2 mmol), solvent (2 mL), sealed tube, in air.
b Isolated yield.
c 2-Oxa = 2-oxazolidinine.
Table 3 Reuse of the [BSPy][CF3SO3] Ionic Liquid for the Hy-
capillary column (30 m × 0.25 mm × 0.25 mm) and an Agilent 5973
mass selective detector.
droamination of NH2Ts with Norbornenea
Recycle number
1st
97
2nd
95
3rd
94
4th
90
Intermolecular Addition Reactions of Amides or Carbamates to
Alkenes; Typical Procedure
Product yield (%)b
Into a test tube were placed [BSPy][CF3SO3] (20% mol), NH2Ts (1
mmol), toluene (2 mL) and cyclohexene (2 mmol) together in air.
After sealing, the mixture was heated at 80 °C and stirred vigorous-
ly for 24 h. After the reaction was completed, the mixture was con-
centrated in vacuo to remove the toluene. The product was then
separated by simple extraction (EtOAc–Et2O, 1:1), and purified by
column chromatography (EtOAc–PE, 1:10 to 1:5) to give the ana-
lytically pure product (72% yield). The insoluble ionic liquid left in
the reaction vessel could be directly recycled for subsequent runs.
All the known compounds were determined by GC-MS or NMR.
a Reaction conditions: norbornene (6 mmol), NH2Ts (3 mmol),
[BSPy][CF3SO3] (0.6 mmol), 85 °C, no solvent, 24 h.
b Isolated yield.
In summary, the use of acidic ionic liquids as catalysts for
the hydroamination of sulfonamides, carboxamides, car-
bamates and anilines to various alkenes in good to excel-
lent yields avoids the use of expensive and air-sensitive
metal reagents or high temperature reaction conditions to
promote the reaction. The acidic ionic liquid
[BSPy][CF3SO3] can be recovered conveniently and re-
used up to four times under solvent-free conditions, al-
though with some loss of activity. Moreover, this
methodology offers significant improvements with regard
to the scope of this transformation, simplicity in opera-
tion, and green aspects by avoiding expensive and toxic
metals catalysts or corrosive catalysts. These advantages
of this novel catalytic system are expected to contribute to
the development of further benign hydroaminations of
amides with alkenes.
Intermolecular Addition Reactions of Amides or Anilines to
Alkenes under Solvent-Free Conditions: General Procedure
Into a test tube were placed [BSPy][CF3SO3] (20% mol), NH2Ts (6
mmol, 1.03 g) and norbornene (12 mmol) together in air. After seal-
ing, the mixture was heated at 85 °C and stirred vigorously for 24 h.
After the reaction was completed, the crude product was then sepa-
rated by simple extraction (EtOAc–Et2O, 1:1) and further purified
by column chromatography to give the pure product (97% yield).
The insoluble ionic liquid left in the reaction vessel could be direct-
ly recycled for subsequent runs.
All the compounds are known and NMR or GC-MS data for some
representative products are given below.
N-Cyclohexyl-p-toluenesulfonamide
White solid; mp 83–85 °C.
All reactions were performed in sealed oven-dried glass tubes in air.
Ionic liquids used were prepared according to previous methods.14
All common reagents were obtained from commercial suppliers and
used without further purification. Thin-layer chromatography
(TLC) was performed on silica gel GF254 eluting with PE–EtOAc,
5:1 unless noted otherwise. Column chromatography was carried
out using silica gel (200–300 mesh) eluting with PE–EtOAc. NMR
spectra were obtained on a Varian spectrometer operating at 400
MHz for 1H and 100 MHz for 13C in CDCl3 unless noted otherwise.
All coupling constants are reported in hertz (Hz). GC-MS data was
obtained on an Agilent 6890-N GC system with an Alltech EC-1
1H NMR (400 MHz): d = 7.77 (d, J = 8.0 Hz, 2 H), 7.28–7.26 (t,
J = 8.0 Hz, 2 H), 4.55 (d, J = 6.4 Hz, 1 H), 3.10–3.07 (m, 1 H), 2.40
(s, 3 H), 1.73–1.70 (m, 2 H), 1.62–1.58 (m, 2 H), 1.50–1.46 (m, 1
H), 1.29–1.06 (m, 5 H).
13C NMR (100 MHz): d = 143.09, 138.40, 129.60, 126.90, 52.53,
33.89, 25.10, 24.60, 21.51.
GC-MS: m/z = 253.
N-Cyclopentyl-p-toluenesulfonamide
White solid; mp 81–83 °C.
Synthesis 2009, No. 12, 1969–1974 © Thieme Stuttgart · New York

PAPER
Catalyzed Hydroamination of Alkenes
1973
1H NMR (400 MHz): d = 7.75 (d, J = 8.0 Hz, 2 H), 7.26 (d, J = 8.0
Hz, 2 H), 4.96 (s, 1 H), 3.56–3.51 (m, 1 H), 2.44 (s, 3 H), 1.73–1.70
(m, 2 H), 1.64–1.59 (m, 2 H), 1.52–1.46 (m, 1 H), 1.25–1.08 (m, 5
H).
13C NMR (100 MHz): d = 143.15, 137.77, 129.59, 127.06, 55.06,
33.30, 23.05, 21.47.
J = 6.8 Hz, 1 H), 2.38 (s, 3 H), 2.27 (s, 3 H), 1.37 (d, J = 6.8 Hz, 3
H).
13C NMR (100 MHz): d = 143.03, 140.00, 137.65, 137.18, 129.42,
129.04, 127.02, 125.86, 53.20, 23.36, 21.41, 21.0.
GC-MS: m/z = 289.
GC-MS: m/z = 239.
N-Phenylethyl-oxazolidinone
Light yellow oil.
N-Cyclohexyl-p-nitrobenzenesulfonamide
White solid; mp 135–137 °C.
1H NMR (400 MHz): d = 8.36–8.32 (m, 2 H), 8.07–8.04 (m, 2 H),
4.77 (d, J = 8.0 Hz, 1 H), 3.23–3.16 (m, 1 H), 1.75–1.72 (m, 2 H),
1.65–1.53 (m, 2 H), 1.53–1.48 (m, 1 H), 1.28–1.07 (m, 5 H).
13C NMR (100 MHz): d = 149.89, 147.41, 128.09, 124.37, 53.09,
33.95, 24.93, 24.55.
1H NMR (400 MHz): d = 7.36–7.24 (m, 5 H), 7.27 (q, J = 6.8, 7.2
Hz, 1 H), 4.30–4.17 (m, 2 H), 3.51–3.44 (m, 1 H), 3.16–3.09 (m, 1
H), 1.55 (d, J = 7.2 Hz, 3 H).
13C NMR (100 MHz): d = 157.91, 139.39, 128.62, 127.80, 126.96,
61.85, 51.35, 39.94, 16.25.
GC-MS: m/z = 191.
GC-MS: m/z = 284.
N-exo-Bicyclo[2.2.1]hept-2-yl-p-toluenesulfonamide
White solid; mp 127–129 °C.
N-Cyclohexylbenzenesulfonamide
White solid; mp 88–90 °C.
1H NMR (400 MHz): d = 7.89–7.86 (m, 2 H), 7.56–7.46 (m, 3 H),
4.85 (br s, 1 H), 3.15–3.08 (m, 1 H), 1.72–1.69 (m, 2 H), 1.62–1.57
(m, 2 H), 1.49–1.44 (m, 1 H), 1.24–1.02 (m, 5 H).
1H NMR (400 MHz): d = 7.73 (d, J = 7.2 Hz, 2 H), 7.28 (d, J = 7.6
Hz, 2 H), 4.61 (d, J = 6.4 Hz, 1 H), 3.10 (s, 1 H), 2.41 (s, 3 H), 2.16
(s, 1 H), 2.07 (s, 1 H), 1.59–1.54 (m, 1 H), 1.43–1.38 (m, 2 H), 1.31–
1.29 (m, 2 H), 1.15–1.03 (m, 2 H), 0.99–0.87 (m, 2 H).
13C NMR (100MHz): d = 143.19, 137.84, 129.63, 127.06, 56.61,
42.44, 40.74, 35.54, 35.14, 27.96, 26.27, 21.51.
13C NMR (100 MHz): d = 141.37, 132.36, 128.98, 126.81, 52.58,
33.81, 25.05, 24.55.
GC-MS: m/z = 265.
GC-MS: m/z = 239.
N-Methyl-N-exo-bicyclo[2.2.1]hept-2-yl-p-methylbenzene-
sulfonamide
N-Cyclohexyl-N-methyl-p-toluenesulfonamide
White solid; mp 74–76 °C.
White solid; mp 76–78 °C.
1H NMR (400 MHz): d = 7.66 (d, J = 8.2 Hz, 2 H), 7.25 (d, J = 8.2
Hz, 2 H), 3.74–3.70 (m, 1 H), 2.69 (s, 3 H), 2.39 (s, 3 H), 1.70–1.68
(m, 2 H), 1.59–1.55 (m, 1 H), 1.46–1.44 (m, 2 H), 1.30–1.22 (m, 4
H), 0.98–0.94 (m, 1 H).
1H NMR (400 MHz): d = 7.63 (d, J = 6.4 Hz, 2 H), 7.25 (d, J = 8.0
Hz, 2 H), 3.82–3.78 (m, 1 H), 2.68 (s, 3 H), 2.38 (s, 3 H), 2.17 (br s,
1 H), 1.83 (br s, 1 H), 1.55–1.48 (m, 1 H), 1.41–1.30 (m, 4 H), 1.16–
1.10 (m, 1 H), 1.06–1.00 (m, 2 H).
13C NMR (100 MHz): d = 142.80, 137.33, 129.57, 126.86, 56.71,
13C NMR (100 MHz): d = 142.95, 136.16, 129.50, 127.16, 59.81,
30.21, 28.56, 25.71, 25.31, 21.47.
39.02, 36.71, 36.55, 35.67, 29.78, 29.10, 27.24, 21.44.
GC-MS: m/z = 267.
GC-MS: m/z = 279.
N-[1-(4-Bromophenyl)ethyl]-p-methylbenzenesulfonamide
Cyclohex-2-enyl-p-toluenesulfonamide
White solid; mp 120–122 °C.
White solid; mp 102–104 °C.
1H NMR (400 MHz): d = 7.57 (d, J = 8.4 Hz, 2 H), 7.27 (d, J = 8.4
Hz, 2 H), 7.16 (d, J = 8.0 Hz, 2 H), 6.97 (d, J = 8.0 Hz, 2 H), 5.42
(d, J = 7.2 Hz, 1 H), 4.41 (quintet, J = 6.8 Hz, 1 H), 2.39 (s, 3 H),
1.37 (d, J = 6.8 Hz, 3 H).
1H NMR (400 MHz): d = 7.75 (d, J = 7.6 Hz, 2 H), 7.27 (d, J = 8.0
Hz, 2 H), 5.71 (d, J = 10 Hz, 1 H), 5.31 (d, J = 10.4 Hz, 1 H), 4.84
(d, J = 8.4 Hz, 1 H), 3.77 (s, 1 H), 2.39 (s, 3 H), 1.94–1.77 (m, 2 H),
1.74–1.61 (m, 1 H), 1.57–1.50 (m, 3 H).
13C NMR (100 MHz): d = 143.32, 140.00, 137.33, 131.43, 129.42,
13C NMR (100 MHz): d = 143.14, 138.24, 131.39, 129.60, 126.95,
127.92, 127.00, 121.16, 53.06, 23.35, 21.47.
126.91, 48.89, 30.12, 24.38, 21.45, 19.22.
GC-MS: m/z = 354.
GC-MS: m/z = 251.
N-[1-(4-Chlorophenyl)ethyl]-p-methylbenzenesulfonamide
Benzyl Cyclohex-2-enylcarbamate
White solid; mp 129–131 °C.
White solid; mp 51–53 °C.
1H NMR (400 MHz): d = 7.58 (d, J = 8.4 Hz, 2 H), 7.16 (d, J = 8.4
Hz, 2 H), 7.14 (d, J = 8.4 Hz, 2 H), 7.01 (d, J = 8.4 Hz, 2 H), 4.76
(d, J = 6.8 Hz, 1 H), 4.45 (quintet, J = 6.8 Hz, 1 H), 2.40 (s, 3 H),
1.38 (d, J = 6.8 Hz, 3 H).
1H NMR (400 MHz): d = 7.34–7.24 (m, 5 H), 5.81 (d, J = 8.8 Hz, 1
H), 5.59 (d, J = 10 Hz, 1 H), 5.08 (m, 2 H), 4.71 (br s, 1 H), 4.19 (br
s, 1 H), 1.96 (s, 2 H), 1.90–1.88 (m, 1 H), 1.62–1.60 (m, 2 H), 1.57–
1.51 (m, 1 H).
13C NMR (100 MHz): d = 143.31, 140.50, 137.36, 133.09, 129.42,
13C NMR (100 MHz): d = 155.60, 136.56, 130.87, 128.51, 128.14,
128.49, 127.57, 127.01, 52.59, 23.42, 21.44.
128.09, 127.65, 66.57, 46.30, 29.70, 24.73, 19.54.
GC-MS: m/z = 310.
GC-MS: m/z = 231.
N-[1-(4-Methylphenyl)ethyl]-p-methylbenzenesulfonamide
N-(4-Nitrophenyl)bicyclo[2.2.1]heptan-2-amine
White solid; mp 118–120 °C.
Yellow solid; mp 115–117 °C.
1H NMR (400 MHz): d = 7.62 (d, J = 8.4 Hz, 2 H), 7.13 (d, J = 8.4
Hz, 2 H), 7.00 (m, 4 H), 4.80 (d, J = 6.8 Hz, 1 H), 4.41 (quintet,
1H NMR (400 MHz): d = 8.09–8.05 (m, 2 H), 6.50–6.46 (m, 2 H),
4.49 (s, 1 H), 3.31 (m, 1 H), 2.35 (s, 1 H), 2.29 (s, 1 H), 1.92–1.86
Synthesis 2009, No. 12, 1969–1974 © Thieme Stuttgart · New York

1974
L. Yang et al.
PAPER
(8) (a) Talluri, S. K.; Sudalai, A. Org. Lett. 2005, 7, 855.
(m, 1 H), 1.56–1.50 (m, 2 H), 1.46–1.43 (dd, J = 8.4, 1.6 Hz 1 H),
1.43–1.16 (m, 4 H).
13C NMR (100 MHz): d = 152.51, 137.57, 126.38, 111.36, 56.32,
41.40, 40.89, 35.62, 35.48, 28.22, 26.22.
(b) Li, Z.; Zhang, J.; Brouwer, C.; Yang, C. G.; Reich, N. W.;
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GC-MS: m/z = 232.
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1077–1236.
Acknowledgment
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We thank the National Natural Science Foundation of China (No.
20572114 and 20533080) and National Natural Science Funds for
Distinguished Young Scholar, P.R. of China (No. 20625308) for fi-
nancial support.
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Synthesis 2009, No. 12, 1969–1974 © Thieme Stuttgart · New York