Zirconium-catalyzed intermolecular hydroamination of unactivated olefins

Article abstract of DOI:10.1055/s-0028-1088151

Highly efficient hydroamination reactions of sulfonamides, carboxamides, and carbamates with unactivated olefins catalyzed by simple and inexpensive zirconium salts under mild reaction conditions were presented for the practical preparation of various amines. These processes gave good to excellent yields of the addition products in Markovnikov addition fashion. Georg Thieme Verlag Stuttgart.

Full text of DOI:10.1055/s-0028-1088151

LETTER
1167
Zirconium-Catalyzed Intermolecular Hydroamination of Unactivated Olefins
a
a,b
a
a
a
a
I
L
ntermolecular
H
e
ydroamin
i
a
tionof Unac
Y
tivatedOlefins ang, Li-Wen Xu,* Wei Zhou, Yue-Hua Gao, Wei Sun, Chun-Gu Xia*
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
Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, Hangzhou Normal University,
Hangzhou 310012, P. R. of China
b
Received 3 November 2008
amides, carboxamides, and carbamates have been report-
ed. Herein we wish to report our recent findings that
Abstract: Highly efficient hydroamination reactions of sulfon-
amides, carboxamides, and carbamates with unactivated olefins cat-
alyzed by simple and inexpensive zirconium salts under mild
reaction conditions were presented for the practical preparation of
14
Zr(OTf) could be used to catalyze the hydroamination
4
between unactivated olefins and sulfonamides, carba-
various amines. These processes gave good to excellent yields of mates, or amides under mild reaction conditions.
the addition products in Markovnikov addition fashion.
Table 1 Catalyst and Solvent Screening for Hydroamination be-
Key words: hydroamination, olefins, amides, carbamates, zirconi-
tween p-Toluenesulfonamide and Cyclohexenea
um salts
NHTs
catalyst
+
NH2Ts
Hydroamination, the simple addition of an N–H bond
across an C–C unsaturated organic fragment, has attracted Entry Catalyst (loading, mol%) Time (h) Solvent
Yield (%)b
1
,2
much attention in the past decades. This synthetic trans-
formation is highly efficient due to the highly atom-
economic synthesis and the readily availability of the
starting materials. Further exploration of the hydroamina-
tion of unactivated alkenes continues to be an important
1
2
3
4
5
6
7
8
9c
0
Cu(OTf) (5)
22
22
22
22
22
22
22
22
24
20
20
20
20
toluene
toluene
toluene
toluene
toluene
toluene
toluene
toluene
toluene
DCE
trace
0
2
Sm(OTf) (10)
3
Ni(OTf) (10)
0
2
3
–5
area of research. Some time ago Marks and coworkers
demonstrated that lanthanide-based catalysts could be
used in hydroamination of a broad substrate scope in both
Zn(OTf) (10)
0
2
Zr(OTf) (5)
94
4
6
the olefin and the amines. Recently, efficient plati-
num(II), gold(I), copper(II), and other metal salts
ZrOCl ·8H O (5)
trace
trace
<10
<10
95
2
2
7
8
9
10
Zr(SO ) ·4H O (5)
were reported to catalyze the hydroamination of amides
and carbamates. Along with the metal catalysts, there
were also examples using metal-free catalysts for the
hydroamination of olefins and amides. Although some
notable progress have been made on the hydroamination
reactions of alkenes with amides in the past two years,
4
2
2
ZrCl (5)
4
1
1
Zr(OTf)
(5)
4
1
Zr(OTf) (5)
4
there were also drawbacks on the reported methods, such 11
as using expensive and toxic metals, higher temperature,
and tedious reaction procedures. Therefore, the develop-
Zr(OTf)
(5)
1,4-dioxane 38
4
1
2
Zr(OTf) (5)
n-heptane
n-heptane
97
96
4
ment of a general, efficient, and readily available or prac- 13
Zr(OTf) (2.5)
4
tical catalyst for hydroamination reactions of unactivated
alkenes with sulfonamides, carboxamides, and carba-
mates is highly desirable.
a
Reactions were conducted in solvent (2 mL) with cyclohexene (2
mmol) and NH Ts (1 mmol) in the presence of different catalyst at
2
8
5 °C.
b
Determined by GC analysis with internal standard.
The reaction was carried out at r.t.
In the past decades, significant progress has been
achieved through the use of group IV metal complexes for
hydroamination reactions of alkynes and allenes.12 How-
c
ever, catalysts using the simple group IV metal salts were In preliminary experiments, hydroamination of cyclohex-
1
3
limited in this reaction. To the best of our knowledge, no ene with p-toluenesulfonamide was carried out in the
example of zirconium-catalyzed intermolecular alkene presence of several readily available Lewis acids in tolu-
hydroamination with weaker nucleophiles such as sulfon- ene at 85 °C (Table 1).15 Zirconium triflate gave the
highest yield of N-cyclohexyl p-toluenesulfonamide
16
(
Table 1, entry 5). Other Lewis acids, such as Zn(OTf)2,
SYNLETT 2009, No. 7, pp 1167–1171
Advanced online publication: 26.03.2009
DOI: 10.1055/s-0028-1088151; Art ID: W17608ST
x
x.
x
x.
2
0
0
9
Sm(OTf) , Ni(OTf) could not catalyze the same reaction
at all even at higher catalyst loading (10 mol%). To vali-
3
2
©
Georg Thieme Verlag Stuttgart · New York

1
168
L. Yang et al.
LETTER
date the unique reactivity of the catalyst, several control These results indicated that the combination of the triflate
experiments were conducted in the presence of other zir- counteranion and the zirconium cation were all very im-
conium salts. For example, ZrSO , ZrCl , and ZrOCl did portant for achieving higher product yield. A series of sol-
4
4
2
not catalyze the hydroamination reaction (entries 6–8). vents was screened (entries 9–12). We found that
Table 2 Hydroamination of Unactivated Olefins with Amidesa
Entry
1
Olefin
Amide
TsNH2
Time (h)
20
Temp (°C) Product
85
Yield (%)b
93c
NHTs
NHTs
2
TsNH2
TsNH2
24
24
85
85
80c
NHTs
+
3d
64 (1:1)
NHTs
NHTs
4d
5e
6d
7d
TsNH2
20
25
20
20
30
45
100
45
90
60
93
68
75
NHCOPh
NHTs
PhCONH2
TsNH2
Br
Br
NHTs
NHTs
TsNH2
r.t.
8e
9f
TsNH2
85
Cl
Cl
NHTs
NMeTs
NHNs
TsNH2
24
24
20
24
40
85
85
95
1
1
1
1
0f
1e
2e
3f
TsNHCH3
p-NsNH2
PhCONH2
TsNH2
82
85
72
NHCOPh
25g
100
90
NHTs
NHTs
68 (2:1)h
+
C6H13
C6H13
C5H11
a
b
c
d
e
f
Reactions were conducted with nucleophiles (1 mmol), olefins (2 mmol), and Zr(OTf) (5 mol%) in n-heptane (2 mL).
Isolated yield.
4
Amount of Zr(OTf) used = 2.5 mol%.
4
Toluene was used as solvent.
1
,4-Dioxane as solvent.
DCE was used as solvent.
g
h
Amount of Zr(OTf) used = 10 mol%.
4
Amount of olefin used = 3 mmol.
Synlett 2009, No. 7, 1167–1171 © Thieme Stuttgart · New York

LETTER
Intermolecular Hydroamination of Unactivated Olefins
1169
coordinating solvents such as 1,4-dioxane tended to shut Table 3 Zr(OTf) -Catalyzed Hydroamination of 1,3-Cyclohexadi-
4
down the reaction, whereas noncoordinating solvents ene with Amines
such as 1,2-dichloroethane (DCE), n-heptane, and toluene
seemed to be ideal. Consequently, good yield was ob-
NHR
Zr(OTf)4 (5 mol%)
+
2
NH R
DCE or dioxane
tained even when using 1 mol% of Zr(OTf) as the cata-
4
lyst (76% of isolated yield).
Entrya Amine
Temp Time Product
Yield
(%)
b
With the above optimized reaction conditions in hand,
hydroamination of various nitrogen nucleophiles and dif-
ferent olefins were also investigated. The results are sum-
marized in Table 2.
(°C)
(h)
1
TsNH2
TsNH2
50
10
86
48
NHTs
Cyclic unactivated alkenes, such as cycloheptene and
cyclohexene, were found to be good acceptors with
2
r.t.
90
10
21
22
24
NHTs
NH Ts (entries 1–3). When using styrene as the olefin
2
3c
4
p-NsNH2
<10
74
(
entry 4), high yield of the addition product was obtained
NHNs
in toluene under mild reaction conditions (45 °C). The
addition of benzamide to styrene also occurred under
modified conditions (entry 5). The reactions of TsNH2
with 4-bromostyrene produced a fast and high-yielding
reaction (entry 6), while the reaction of 4-chlorostyrene
was somewhat slower (entry 8). Interestingly, in the pres-
ence of electron-donating groups such as 4-Me, the reac-
tions could be carried out at room temperature in good hexadiene (1.2 mmol), and Zr(OTf)
yield (entry 7). Additions of amide to the more strained
norbornene were also studied (entries 9–12). For example,
best yields were obtained with NH Ts or TsNHCH , and
NH Cbz
50
2
NHCbz
NHCOPh
5d
PhCONH2
100
55
a
Reactions were conducted with nucleophiles (1 mmol), 1,3-cyclo-
(5 mol%) in DCE (2 mL).
4
b
Isolated yield.
c
1
,4-Dioxane was used as solvent.
d
The amount of 10 mol% of Zr(OTf) was used.
4
2
3
moderate yield with the less nucleophilic 4-nitrobenzene-
source are the advantages of this process. Although the
exact mechanism was not clear at this current stage, on the
basis of the results obtained from the group IV metal com-
plex catalyzed hydroamination reactions,1 the genera-
tion of zirconium–imido complexes was probably
involved in our present reaction. Further explorations of
this work to asymmetric hydroamination and other heter-
ofunctionalization of olefin or alkynes are undergoing in
our groups.
sulfonamide (p-NsNH ). It should be noted that the reac-
2
tion of benzamide and norbornene was very sluggish,
affording product in 25% yield after 24 hours using 10
2,13
mol% Zr(OTf) as the catalyst. The reaction between
4
TsNH and an excess (3 equiv) of 1-octene occurred in
2
moderate yield to form an approximately 2:1 ratio of the
2
- and 3-N-octyl tosylamides (entry 13).
Next, we further extended the scope of this methodology
by subjecting various amides as nucleophiles for the
1
7
hydroamination of 1,3-cyclohexadiene. As shown in
Supporting Information for this article is available online at
http://www.thieme-connect.com/ejournals/toc/synlett.
Table 3, the catalytic hydroamination of NH Ts with 1,3-
2
cyclohexadiene in the presence of 5% Zr(OTf) was near-
4
ly completed after 10 hours at 50 °C to form the addition
product in 86% isolated yield (Table 3, entry 1). Remark-
ably, this addition reaction could proceed smoothly at
room temperature. This demonstrated the unique catalytic
activity of Zr(OTf) as compared to Cu(OTf) , which was
Acknowledgment
We thank the National Natural Science Foundation of China
(
No.20572114) and National Natural Science Funds for Distin-
4
2
guished Young Scholar, P. R. China (No.20625308) for financial
support.
ineffective alone in the hydroamination of NH Ts with
2
9
1
,3-cyclohexadiene. It was interesting to find that p-
NsNH was not a suitable candidate for this reaction (en-
try 3). Zirconium triflate was also applied to hydroamina-
2
References and Notes
tion of NH Cbz with 1,3-cyclohexadiene to give products
in good yield (entry 4). On the other hand, lower reactive
2
(1) For selected recent reviews, see: (a) Müller, T. E.; Beller, M.
Chem. Rev. 1998, 98, 675. (b) Roesky, P. W.; Müller, T. E.
Angew. Chem. Int. Ed. 2003, 42, 2708. (c) Bystschkov, I.;
Doye, S. Eur. J. Org. Chem. 2003, 935. (d) Hultzsch, K. C.
Adv. Synth. Catal. 2005, 347, 367. (e) Hazari, N.;
PhCONH and 1,3-cyclohexadiene only gave moderate
2
results even at relatively higher temperature (entry 5).
In summary, we presented herein that Zr(OTf) could ef-
4
Mountford, P. Acc. Chem. Res. 2005, 38, 839.
ficiently catalyze the addition of sulfonamides, carbox-
amides, and carbamates to various unactivated olefins.
The wide substrate scope, relatively inexpensive catalyst,
simple operation, and lower ratio of olefin to nitrogen
(
2) (a) Pohlki, F.; Doye, S. Chem. Soc. Rev. 2003, 32, 104; and
references therein. (b) Hartwig, J. F. Pure Appl. Chem.
2004, 76, 507. (c) Severin, R.; Doye, S. Chem. Soc. Rev.
2007, 36, 1407.
Synlett 2009, No. 7, 1167–1171 © Thieme Stuttgart · New York

1
170
L. Yang et al.
LETTER
(9) Taylor, J. G.; Whittall, N.; Hii, K. K. Org. Lett. 2006, 8,
(
3) Representative examples in the catalytic hydroamination.
For lanthanide complexes, see: (a) Kim, Y. K.;
3561.
Livinghouse, T.; Horino, Y. J. Am. Chem. Soc. 2003, 125,
(10) (a) Huang, J. M.; Wong, C. M.; Xu, F. X.; Loh, T. P.
Tetrahedron Lett. 2007, 48, 3375. (b) Michaux, J.;
Terrasson, V.; Marque, S.; Wehbe, J.; Prim, D.; Campagne,
J. M. Eur. J. Org. Chem. 2007, 2601. (c) Qin, H.;
Matsunaga, S.; Yamagiwa, N.; Shibasaki, M. Chem. Asian J.
2007, 2, 150. (d) Qin, H.; Yamagiwa, N.; Matsunaga, S.;
Shibasaki, M. J. Am. Chem. Soc. 2006, 128, 1611.
(11) (a) Talluri, S. K.; Sudalai, A. Org. Lett. 2005, 7, 855.
(b) Li, Z.; Zhang, J.; Brouwer, C.; Yang, C. G.; Reich, N. W.;
He, C. Org. Lett. 2006, 8, 4175. (c) Rosenfeld, D. C.;
Shekhar, S.; Takemiya, A.; Utsunomiya, M.; Hartwig, J. F.
Org. Lett. 2006, 8, 4179. (d) Motokura, K.; Nakagiri, N.;
Mori, K.; Mizugaki, K.; Ebitani, T.; Jitsukawa, K.; Kaneda,
K. Org. Lett. 2006, 8, 4617.
(12) (a) Bytschkov, I.; Doye, S. Eur. J. Org. Chem. 2003, 935.
(b) Lee, A. V.; Schafer, L. L. Eur. J. Org. Chem. 2007,
2243. (c) Shi, Y.; Ciszewski, J. T.; Odom, A. L.
Organometallics 2001, 20, 3967. (d) Johnson, J. S.;
Bergman, R. G. J. Am. Chem. Soc. 2001, 123, 2923.
(e) Ackermann, L. Organometallics 2003, 22, 4367.
(f) Kim, H.; Kim, Y. K.; Shim, J. H.; Kim, M.; Han, M. J.;
Livinghouse, T.; Lee, P. H. Adv. Synth. Catal. 2006, 348,
2609.
9560. (b) Kim, H.; Livinghouse, T.; Shim, J. H.; Lee, S. G.;
Lee, P. H. Adv. Synth. Catal. 2006, 348, 701; and references
cited therein. Alkali metals: (c) Ichikawa, J.; Lapointe, G.;
Iwai, Y. Chem. Commun. 2007, 2698. Iridium: (d) Dorta,
R.; Egli, P.; Zürcher, F.; Togni, A. J. Am. Chem. Soc. 1997,
119, 10857. (e) Zhao, J.; Goldman, A. S.; Hartwig, J. F.
Science 2005, 307, 1080. Rhodium: (f) Takemiya, A.;
Hartwig, J. F. J. Am. Chem. Soc. 2006, 128, 6042.
(
g) Beller, M.; Thiel, O. R.; Trauthwein, H.; Hartung, C. G.
Chem. Eur. J. 2000, 6, 2513. (h) Utsunomiya, M.; Kuwano,
R.; Kawatsura, M.; Hartwig, J. F. J. Am. Chem. Soc. 2003,
1
25, 5608. Nickel: (i) Pawlas, J.; Nakao, Y.; Kawatsura, M.;
Hartwig, J. F. J. Am. Chem. Soc. 2002, 124, 3669.
j) Fadini, L.; Togni, A. Chem. Commun. 2003, 30.
(
Palladium: (k) Minami, T.; Okamoto, H.; Ikeda, S.; Tanaka,
R.; Ozawa, F.; Yoshifuji, M. Angew. Chem. Int. Ed. 2001,
40, 4501. (l) Utsunomiya, M.; Hartwig, J. F. J. Am. Chem.
Soc. 2003, 125, 14286. Platinum: (m) Brunet, J. J.; Chu,
N. C.; Rodriguez-Zubiri, M. Eur. J. Inorg. Chem. 2007,
4711. Gold: (n) Nishina, N.; Yamamoto, Y. Angew. Chem.
Int. Ed. 2006, 45, 3314. (o) Han, X.; Widenhoefer, R. A.
Angew. Chem. Int. Ed. 2006, 45, 1747. For a review, see:
(
4
p) Widenhoefer, R. A.; Han, X. Q. Eur. J. Org. Chem. 2006,
555. Ruthenium: (q) Utsunomiya, M.; Hartwig, J. F. J. Am.
(13) (a) Ackermann, L.; Kaspar, L. T.; Gschrei, C. J. Org. Lett.
2004, 6, 2515. (b) Kaspar, L. T.; Benjamin, F.; Ackermann,
L. Angew. Chem. Int. Ed. 2005, 44, 5972. (c) Abbiati, G.;
Casoni, A.; Canevari, V.; Nava, D.; Rossi, E. Org. Lett.
2006, 8, 4839. (d) Ackermann, L.; Kaspar, L. T. J. Org.
Chem. 2007, 72, 6149. (e) Ackermann, L.; Kaspar, L. T.;
Althammer, A. Org. Biomol. Chem. 2007, 5, 1975.
(14) During the preparation of our manuscript, several related
papers using other metal salts dealing with the
Chem. Soc. 2004, 126, 2702. (r) Takaya, J.; Hartwig, J. F.
J. Am. Chem. Soc. 2005, 127, 5756. Main-group metals:
(
s) Lauterwasser, F.; Hayes, P. G.; Bräse, S.; Piers, W. E.;
Schafer, L. L. Organometallics 2004, 23, 2234.
t) Crimmin, M. R.; Casely, I. J.; Hill, M. S. J. Am. Chem.
(
Soc. 2005, 127, 2042. (u) Wei, H.; Qian, G. M.; Xia, Y. Z.;
Li, K.; Li, Y. H.; Li, W. Eur. J. Org. Chem. 2007, 4471.
4) Brønsted acids: (a) Schlummer, B.; Hartwig, J. F. Org. Lett.
(
intermolecular hydroamination of styrenes have appeared in
the literature, see ref. 10a–c.
2
002, 4, 1471. (b) Anderson, L. L.; Arnold, J.; Bergman,
R. G. J. Am. Chem. Soc. 2005, 127, 14542. (c) Rosenfeld,
D. C.; Shekhar, S.; Takemiya, A.; Utsunomiya, M.; Hartwig,
J. F. Org. Lett. 2006, 8, 4179. (d) Marcseková, I.; Doye, S.
Synthesis 2007, 145. (e) Jazzar, R.; Dewhurst, R. D.; Bourg,
J. B.; Donnadieu, B.; Canac, Y.; Bertrand, G. Angew. Chem.
Int. Ed. 2007, 46, 2899. (f) Yang, L.; Xu, L. W.; Xia, C. G.
Tetrahedron Lett. 2008, 49, 2882.
(15) Typical Procedure for Intermolecular Addition
Reactions of Olefins
Into a test tube were placed Zr(OTf) (0.05 mmol) and
4
NH Ts (1 mmol). After the test tube was sealed, it was
2
purged three times with argon, then n-heptane (2 mL) and
cyclohexene (2 mmol) were injected. The reaction mixture
was heated at 85 °C and stirred vigorously for 20 h. After the
reaction was completed, the mixture was directly applied to
(
5) Recent representative progress: (a) LaLonde, R. L.; Sherry,
B. D.; Kang, E. J.; Toste, F. D. J. Am. Chem. Soc. 2007, 129,
column chromatography using SiO (EtOAc–PE, 1:10 to
2
2
452. (b) Wood, M. C.; Leitch, D. C.; Yeung, C. S.; Kozak,
J. A.; Schafer, L. L. Angew. Chem. Int. Ed. 2007, 46, 354.
c) Guin, J.; Mück-Lichtenfeld, C.; Grimme, S.; Studer, A.
1:5) to afford a analytically pure product (93% isolated
yield). All the compounds are known and NMR or GC-MS
data for some representative products are given below.
(
J. Am. Chem. Soc. 2007, 129, 4498. (d) Nishina, N.;
Yamamoto, Y. Synlett 2007, 1767. (e) Horrillo-Martinez,
P.; Hultzsch, K. C.; Gil, A.; Branchadell, V. Eur. J. Org.
Chem. 2007, 3311. (f) Yin, Y.; Ma, W.; Chai, Z.; Zhao, G.
J. Org. Chem. 2007, 5731. (g) Lingaiah, N.; Babu, N. S.;
Reddy, K. M.; Prasad, P. S. S.; Suryanarayana, I. Chem.
Commun. 2007, 278. (h) For a review, see: Chemler, S. R.;
Fuller, P. H. Chem. Soc. Rev. 2007, 36, 1153.
N-(1-Phenylethyl)benzamide
1
H NMR (400 MHz, CDCl ): d = 7.77 (d, J = 7.2 Hz, 2 H),
3
7.50–7.46 (t, 1 H), 7.42–7.35 (m, 6 H), 7.33–7.25 (m, 1 H),
6.44 (br, 1 H), 5.34 (dt, J = 7.2, 7.2 Hz, 1 H), 1.60 (d, J = 6.8
1
3
Hz, 3 H). C NMR (100 MHz, CDCl ): d = 166.56, 143.08,
3
134.51, 131.42, 128.70, 128.50, 127.40, 126.89, 126.21,
49.17, 21.68. GC-MS: m/z = 225.
N-[1-(4-Bromophenyl)ethyl]-4-methylbenzenesulfon-
(
(
6) Ryu, J. S.; Li, G. Y.; Marks, T. J. J. Am. Chem. Soc. 2003,
amide
1
1
25, 12584.
7) (a) Qian, H.; Widenhoefer, R. A. Org. Lett. 2005, 7, 2635.
b) Karshtedt, D.; Bell, A. T.; Tilley, T. D. J. Am. Chem. Soc.
005, 127, 12640.
8) (a) Zhang, J. L.; Yang, C. G.; He, C. J. Am. Chem. Soc. 2006,
H NMR (400 MHz, CDCl ): d = 7.57 (d, J = 8.4 Hz, 2 H),
3
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 (quint,
J = 6.8 Hz, 1 H), 2.39 (s, 3 H), 1.37 (d, J = 6.8 Hz, 3 H).
(
2
1
3
(
C NMR (100 MHz, CDCl ): d = 143.32, 140.00, 137.33,
3
1
8
2
28, 1798. (b) Liu, X. Y.; Li, C.; Che, C. M. Org. Lett. 2006,
, 2707. (c) Bender, C. F.; Widenhoefer, R. A. Org. Lett.
006, 8, 5303. (d) Brouwer, C.; He, C. Angew. Chem. Int.
131.43, 129.42, 127.92, 127.00, 121.16, 53.06, 23.35, 21.47.
GC-MS: m/z = 354.
Cyclohex-2-enyl-p-toluenesulfonamide
1
Ed. 2006, 45, 1744.
H NMR (400 MHz, CDCl ): d = 7.75 (d, J = 7.6 Hz, 2 H),
3
7
.27 (d, J = 8.0 Hz, 2 H), 5.71 (d, J = 10.0 Hz, 1 H), 5.31 (d,
Synlett 2009, No. 7, 1167–1171 © Thieme Stuttgart · New York

LETTER
J = 10.4 Hz, 1 H), 4.84 (d, J = 8.4 Hz, 1 H), 3.77 (s, 1 H),
Intermolecular Hydroamination of Unactivated Olefins
1171
(16) Zr(OTf) was prepared according to reported methods:
4
2
1
1
2
.39 (s, 3 H), 1.94–1.77 (m, 2 H), 1.74–1.61 (m,1 H), 1.57–
(a) Kobayashi, S.; Iwamoto, S.; Nagayama, S. Synlett 1997,
1099. (b) Shi, M.; Yang, Y. H.; Xu, B. Synlett 2004, 1622.
(17) Allylamines are fundamental building blocks in organic
chemistry. For a review, see: Johannsen, M.; Jørgensen,
K. A. Chem. Rev. 1998, 98, 1689.
1
3
.50 (m, 3 H). C NMR (100 MHz, CDCl ): d = 143.14,
3
38.24, 131.39, 129.60, 126.95, 126.91, 48.89, 30.12, 24.38,
1.45, 19.22. GC-MS: m/z = 251.
Synlett 2009, No. 7, 1167–1171 © Thieme Stuttgart · New York

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