Highly enantioselective construction of trifluoromethylated all-carbon quaternary stereocenters via nickel-catalyzed friedel-crafts alkylation reaction

Article abstract of DOI:10.1021/ja400650m

A highly enantioselective Friedel-Crafts alkylation reaction of indoles with β-CF₃-β-disubstituted nitroalkenes was achieved using a Ni(ClO₄)₂-bisoxazoline complex as a catalyst, which afforded indole-bearing chiral compou

Full text of DOI:10.1021/ja400650m

Subscriber access provided by UNIV OF MICHIGAN
Communication
Highly Enantioselective Construction of Trifluoromethylated
All-carbon Quaternary Stereocenters via Nickel-
catalyzed Friedel-Crafts Alkylation Reaction
Jian-Rong Gao, Hao Wu, Bin Xiang, Wu-Bin Yu, Liang Han, and Yi-xia Jia
J. Am. Chem. Soc., Just Accepted Manuscript • DOI: 10.1021/ja400650m • Publication Date (Web): 14 Feb 2013
Downloaded from http://pubs.acs.org on February 17, 2013
Just Accepted
“Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted
online prior to technical editing, formatting for publication and author proofing. The American Chemical
Society provides “Just Accepted” as a free service to the research community to expedite the
dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts
appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been
fully peer reviewed, but should not be considered the official version of record. They are accessible to all
readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered
to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published
in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just
Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor
changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers
and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors
or consequences arising from the use of information contained in these “Just Accepted” manuscripts.
Journal of the American Chemical Society is published by the American Chemical
Society. 1155 Sixteenth Street N.W., Washington, DC 20036
Published by American Chemical Society. Copyright © American Chemical Society.
However, no copyright claim is made to original U.S. Government works, or works
produced by employees of any Commonwealth realm Crown government in the course
of their duties.

Page 1 of 5
Journal of the American Chemical Society
1
2
3
4
5
6
7
8
9
Highly Enantioselective Construction of Trifluoromethylated
All-carbon Quaternary Stereocenters via Nickel-catalyzed
Friedel-Crafts Alkylation Reaction
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Jian-Rong Gao, Hao Wu, Bin Xiang, Wu-bin Yu, Liang Han, and Yi-Xia Jia*
College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310014, China
Supporting Information Placeholder
oximes as nucleophiles.12 Herein, we communicated for the first
ABSTRACT: A highly enantioselective Friedel-Crafts alkylation
time the asymmetric Friedel-Crafts alkylation reaction with β,β-
reaction of indoles with β-CF3-β-disubstituted nitroalkenes was
disubstituted nitroalkenes as alkylating reagents. The reaction
between indoles and β-CF3-β-disubstituted nitroalkenes was effi-
achieved using Ni(ClO4)2-bisoxazoline complex as a catalyst,
ciently catalyzed by a Ni(ClO4)2-bisoxazoline complex13 and
which afforded indole-bearing chiral compounds with trifluoro-
methylated all-carbon quaternary stereogenic centers in good
formed trifluoromethylated all-carbon quaternary stereocenters in
excellent enantioselectivities (Scheme 1).14 Notably, the resulting
adduct was further transformed by sequential nitro reduction and
Pictet-Spengler cyclization to the trifluoromethylated tryptamine
7 and tetrahydro-β-carboline 8 as potentially biologically active
molecules.
yields and excellent enantioselectivities (up to 97% ee). Trans-
formations of the product to trifluoromethylated tryptamine and
tetrahydro-β-carboline by sequential nitro reduction and Pictet-
Spengler cyclization were realized with complete preservation of
enantiopurities.
Scheme 1
Trifluoromethylated organic compounds of pharmaceutical and
agrochemical importance have received increasing attention be-
cause of the unique impact of trifluoromethyl (CF3) group on the
enhancement and modification of their original biological activi-
ties.1 Consequently the development of reliable synthetic ap-
proaches to CF3-bearing organic compounds has been a focused
topic.2 So far, methods to form CF3-substituted tertiary or hetero-
quaternary stereogenic centers have been successfully developed.
Recent examples included the direct asymmetric trifluoromethyla-
tion based on the utilizations of nucleophilic, electrophilic, and
radical trifluoromethylation reagents, as well as enantioselective
transformations of prochiral trifluoromethylated substrates.3 In
spite of these notable advances, the enantioselective construction
of trifluoromethylated all-carbon quaternary stereocenters is much
less exploited and remains a very important and extremely chal-
lenging task in asymmetric catalysis.4 Only few examples docu-
mented for this purpose, including the electrophilic trifluorometh-
ylation of β-ketoesters and the conjugate addition of cyanide to β-
aryl-β-CF3 enones.5 Hence, the development of novel and effi-
cient methods toward this challenge is highly valuable.
Scheme 2
Initially, the nitroalkenes were synthesized according to the
procedure illustrated in Scheme 2.15 Henry reaction of trifluoro-
methylated ketones with nitromethane gave the corresponding
nitroalcohols. Followed elimination of nitroalcohols in the pres-
ence of SOCl2 and pyridine produced (E)-β-CF3-β-disubstituted
nitroalkenes16 in modest yields. (E)-1-Phenyl-1-trifluoromethyl
nitroethene (1a) and indole (2a) were then chosen as model sub-
strates to study the Friedel-Crafts reaction. Primary results
showed that the bisoxazoline ligand could efficiently promote the
reaction.17 With achiral bisoxazoline L1 as a ligand and 10 mol%
Recently, Michael-type asymmetric Friedel-Crafts alkylation
reaction of electron-deficient olefins has been established as im-
portant accesses to chiral benzylic stereocenters.6 However, appli-
cation of this methodology for the synthesis of all-carbon quater-
nary stereocenters was conspicuously limited. To date, only two
examples were reported with modest ees through LUMO-
activation of β,β-disubstituted enaldehydes and enones by imini-
um catalysis.7 The limited success was mainly due to the intrinsic
steric hindrance and poor reactivity of these substrates. β-
Monosubstituted nitroalkene has turned out to be active substrate
in the asymmetric Friedel-Crafts alkylations of indoles,8 pyrroles,9
furans,10 and phenols.11 Utilization of the corresponding β,β-
disubstituted nitroalkene as substrate has not been disclosed yet in
this field although few reports have appeared on the enantioselec-
tive conjugate additions with dialkylzinc reagents, thiols, and
o
Ni(ClO4)2·6H2O as catalyst in toluene at 100 C for 24 h, the de-
sired product was isolated in 75% yield (Table 1, entry 1). Our
attention was then moved to chiral bisoxazoline ligands L2-L5
bearing different substituents on the C4 position of oxazoline ring.
Good enantioselectivities were obtained with L4 and L5 as lig-
ands (entries 2-3), while L2 and L3 led to very poor enantiomeric
excess (4% ee for L2 and 7% ee for L3). Further ligand examina-
tions included L6-L8 with different linkers between the two oxa-
zoline rings and L9-L10 containing additional phenyl group (en-
tries 4-8). Ligand L10 bearing trans-diphenyl groups was found
to be the best choice to give the highest enantioselectivity. The
effect of Lewis acid was subsequently screened. Zn(ClO4)2·6H2O
ACS Paragon Plus Environment

Journal of the American Chemical Society
Page 2 of 5
and Ni(OTf)2 proved to be efficient catalysts while no reaction
(entries 10 and 13). The yields were also influenced unfavorably
1
2
3
4
5
6
7
8
proceeded in the presence of Cu(ClO4)2·6H2O (entries 9-11).
Lowering the temperature to 60 C, both the yield and enantiose-
lectivity were obviously increased albeit with longer reaction time
by the steric effect of the substrate. For example, modest yields
were obtained for the products 3ga, 3ha, and 3na, containing 3,5-
disubstituted phenyl and 2-naphthyl groups (entries 8 and 15).
Moreover, no reaction took place for nitroalkene 1d containing an
ortho-tolyl group (entry 5). Noteworthy, the heteroaromatic sub-
stituted product 3ma and multi-fluorinated products 3ja-3la were
isolated in good yields and with excellent enantioselectivities
(entries 11-14). The reaction was also successfully extended to
alkylated substrates. Good to excellent enantioselectivities were
generally obtained for the reactions of substrates 1p-1s (entries
17-20). Exception was that substrate 3o bearing a benzyl group
led to significant low ee (entry 16).
o
(entry 12). The enantioselectivity was further increased to 97% ee
o
at 50 C but the yield was lowered (entry 13). Solvent screening
showed that the reactions were fully suppressed in tetrahydrofuran
(THF) and methanol. It is worth noting that no detrimental effect
on the enantioselectivity was observed when the reaction was
carried out under air atmosphere or at 5 mol% of catalyst loading
although longer reaction time was required to ensure good yield
(entries 14-15).
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Table 1 Optimization of the reaction conditionsa
Table 2 Substrate scope of nitroalkenea
Entry
R
Product
Yield Ee
(%)
(%)
95
88
87
91
ndc
82
96
78
72
72
87
86
80
96
69
78
88
84
97
96
1
2b
96
96
95
96
--
Ph (1a)
3aa
3aa
3ba
3ca
3da
3ea
3fa
Ph (1a)
3
3-Me-Ph (1b)
4-Me-Ph (1c)
2-Me-Ph (1d)
3-MeO-Ph (1e)
4-MeO-Ph (1f)
3,4-(MeO)2-Ph (1g)
3,5-Me2-Ph (1h)
4-Cl-Ph (1i)
4
5
Entry
LA
L*
Temp. Yield Ee
(oC)
100
100
100
100
100
100
100
100
100
100
100
60
(%)
75
85
84
86
87
80
88
89
80
<5
85
95
87
72
82
(%)
6
92
96
88
93
92
95
95
95
96
95
33
97
88
87
89
1
Ni(ClO4)2·6H2O
Ni(ClO4)2·6H2O
Ni(ClO4)2·6H2O
Ni(ClO4)2·6H2O
Ni(ClO4)2·6H2O
Ni(ClO4)2·6H2O
Ni(ClO4)2·6H2O
Ni(ClO4)2·6H2O
Zn(ClO4)2·6H2O
Cu(ClO4)2·6H2O
Ni(OTf)2
--
L1
7
2
90
86
91
71
87
90
93
84
--
L4
8
3ga
3ha
3ia
3
L5
9
4
L6
10
11
12
13
14
15
16
17
18
19
20
5
L7
3-F-Ph (1j)
3ja
6
L8
3-CF3-Ph (1k)
4-CF3-Ph (1l)
3-Thienyl (1m)
2-Naphthyl (1n)
Benzyl (1o)
3ka
3la
7
L9
8
L10
L10
L10
L10
L10
L10
L10
L10
3ma
3na
3oa
3pa
3qa
3ra
3sa
9
10
11
12b
13c
14d
15e
89
96
97
96
96
2-Phenylethyl (1p)
3-Phenylpropyl (1q)
2-Phenoxybutyl (1r)
1-Octyl (1s)
Ni(ClO4)2·6H2O
Ni(ClO4)2·6H2O
Ni(ClO4)2·6H2O
Ni(ClO4)2·6H2O
50
60
60
a
Reactions conditions:
1 (0.4 mmol), 2a (0.6 mmol),
a The reaction of 1a (0.4 mmol) and 2a (0.6 mmol) was performed
in the presence of 10 mol% Lewis acid and 12 mol% chiral ligand
in toluene (4.0 mL) at the indicated temperature for 24 h unless
otherwise noted, isolated yield, ee was determined by chiral
Ni(ClO4)2·6H2O (10 mol%), ligand L10 (12 mol%) in toluene
o
(4.0 mL) at 60 C for 48-72 h, isolated yield, ee was determined
b
by chiral HPLC. 1a (4.0 mmol) and 2a (6.0 mmol) in 30 mL
toluene. c not detected
b
c
d
e
HPLC. for 48 h. for 72 h. under air for 72 h. 5 mol%
Ni(ClO4)·6H2O and 6 mol% L10, for 96 h.
The substituent effect of indole was then examined. Excellent
enantioselectivities were achieved for indoles bearing either elec-
tron-withdrawing groups or electron-donating groups on C4-C7
positions (entries 1-7). A slow reaction was observed for 5-Br-
indole and the product 3ae was isolated in only 42% yield (entry
Under the optimal reaction conditions, a wide range of nitroal-
kenes (1a-1n) were investigated and the results were outlined in
Table 2. The nitroalkenes bearing para- or meta-substituents on
the phenyl ring were well tolerated, and their reactions with in-
dole underwent smoothly to afford the corresponding products in
excellent enantioselectivities (over 90% ee for most cases, entries
1-15). Relatively lower yields were obtained for products 3ia and
3la, showing that the electronic nature of para- electron-
withdrawing substituents has a negative effect on the reactivity
o
4). Gratifyingly, it was improved to 85 % when heating to 80 C
and the ee value was kept as the same (entry 5). 1-Me-indole and
2-Me-indole were proved to be inferior substrates (entries 8-9).
Product 3ai was obtained in 15% ee for the reaction of 2-Me-
indole with 1a, while only trace amount of the product 3ah was
observed in the case of 1-Me-indole.
ACS Paragon Plus Environment

Page 3 of 5
Journal of the American Chemical Society
Table 3. Substrate scope of indolea
We next examined the transformations of 3aa to the corre-
1
2
3
4
5
6
7
8
sponding trifluoromethylated tryptamine and tetrahydro-β-
carboline as potentially biologically active compounds. As seen in
Scheme 3, the nitro reduction of 3aa by NaBH4/NiCl2·6H2O in
methanol at room temperature afforded tryptamine 7 in 92% yield
and 96% ee. Through a CF3CO2H-mediated Pictet-Spengler cy-
clization of 7 with benzaldehyde, the trifluoromethylated tetrahy-
dro-β-carboline 8, an important structural motif in biologically
active alkaloids, was isolated in 78% yield with 1:2 of diastereo-
meric ratio and 96% ee for both isomers.
Entry
R
Product
Yield Ee
(%)
92
92
89
42
85
86
95
(%)
1
97
96
97
96
96
90
96
4-MeO (2b)
5-MeO (2c)
5-Me (2d)
5-Br (2e)
3ab
3ac
3ad
3ae
3ae
3af
3ag
3ah
3ai
9
2
Scheme 3. Synthetic transformations of product 3aa
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
3
4
5b
6b
7
5-Br (2e)
6-Cl (2f)
7-Me (2g)
1-Me (2h)
2-Me (2i)
b
a NaBH4 (5.0 eq.), NiCl2·6H2O (1.0 eq.), MeOH, r.t., 30 min..
8
trace --
85 15
2 (0.6 mmol),
PhCHO (1.2 eq.), CF3CO2H (2 eq.), MgSO4, CH2Cl2, r.t., 4 days.
9
In conclusion, we have developed a highly enantioselective
Ni(ClO4)2-bisoxazoline complex catalyzed Michael-type Friedel-
Crafts alkylation reaction of indoles with β-trifluoromethyl-β-
disubstituted nitroalkenes. It represents the first highly enantiose-
lective Friedel-Crafts alkylation reaction to construct all-carbon
quaternary stereocenters and provides a reliable strategy for the
synthesis of trifluoromethyl-substituted chiral benzylic com-
pounds. Further extension of this methodology in organic synthe-
sis is currently underway in the laboratory.
a
Reactions conditions: 1a (0.4 mmol),
Ni(ClO4)2·6H2O (10 mol%), ligand L10 (12 mol%) in toluene
o
(4.0 mL) at 60 C for 48 h, isolated yield, ee was determined by
chiral HPLC. b at 80 oC for 72 h.
Pyrrole was also tested as substrate in this Friedel-Crafts reac-
tion. As shown in eq. 1, in the presence of 10 mol%
Ni(ClO4)2·6H2O and 12 mol% L10 the reaction of pyrrole with 1a
proceeded smoothly to afford the product 4 in 51% yield and with
96% ee. In addition, the reactions of indole with β-
methylnitrostyrene (E)-5a and (Z)-5b, structurally similar to ni-
troalkene 1a, were carried out under the identical reaction condi-
tions (eq. 2). Significant lower ee values of 33% and 61% were
detected, respectively, which revealed the unique fluorine effect
of CF3-bearing substrate on the enantioselectivity.18
ASSOCIATED CONTENT
Supporting Information
1
Full experimental and characterization data, including H,
13C, and 19F NMR for all the new compounds, chiral HPLC
spectra for the products, and crystal data are available free
of charge via the Internet at http://pubs.acs.org.
AUTHOR INFORMATION
Corresponding Author
yxjia@zjut.edu.cn
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENT
The absolute configuration of product 3ae was determined to
be R based on the X-ray analysis of its single crystal structure. A
possible model for asymmetric induction was then depicted in
Figure 1. The nitroalkene coordinated to Ni(II) through a 1,3-
binding fashion8c,d and the Re-face attack of indole at the β-
position of nitroalkene was favored.13c
We are grateful for the generous financial support by the National
Natural Science Foundation of China (21002089) and young
scholarship for the doctoral program of higher education
(20103317120001). YXJ dedicates this work to Professor Qi-Lin
Zhou on the occasion of his 55th birthday and to Professor E.
Peter Kündig on the occasion of his retirement.
REFERENCES
O
Ph
(1) (a) Kirsch, P. Modern Fluoroorganic Chemistry: Synthesis, Reactivity,
Applications; Wiley-VCH: Weinheim, 2004. (b) Müller, K.; Faeh, C.;
Diederich, F. Science 2007, 317, 1881. (c) Bégué, J.,-P.; Bonnet-
Delpon, D. Bioorganic and Medicinal Chemistry of Fluorine; Wiley-
VCH, Weinheim, 2008. (d) Hagmann,W., K. J. Med. Chem. 2008,
51, 4359. (e) Filler, R; Saha, R. Future Med. Chem. 2009, 1, 777. (f)
Ojima, I. Fluorine in Medicinal Chemistry and Chemical Biology;
Wiley, Chichester, 2009. (g) Lin, G.-Q.; You, Q.-D.; Cheng, J.-F.
N
F3C
O
Ni
O
N
O
(R) NO2
Br
Ph
5-Br-indole
Re-face
approach
N
N
H
CF3
X
3ae
Figure 1. Proposed model for asymmetric induction
ACS Paragon Plus Environment

Journal of the American Chemical Society
Page 4 of 5
Chiral Drugs: Chemistry and Biological Action; Wiley-VCH: Hobo-
Chem. Soc. 2000, 122, 10710. (f) Kennosuke, I.; Kanemasa, S. J. Am.
ken, 2011.
Chem. Soc. 2002, 124, 13394. (g) Sibi, M. P.; Ma, Z.; Jasperse, C. P.
J. Am. Chem. Soc. 2005, 127, 5764. (h) Shibata, N.; Kohno, J.; Takai,
K.; Ishimaru, T.; Nakamura, S.; Toru, T.; Kanemasa, S. Angew.
Chem., Int. Ed.2005, 44, 4204. (i) Suga, H.; Funyu, A.; Kakehi, A.
Org. Lettt. 2007, 9, 97. (j) Lifchits, O.; Charette, A. B. Org. Lett.
2008, 10, 2809. (k) Shi, J.-W.; Zhao, M.-X.; Lei, Z.-Y.; Shi, M. J.
Org. Chem. 2008, 73, 305. (l) Suga, H.; Furihata, Y.; Sakamoto, A.;
Itoh, K.; Okumura, Y.; Tsuchida, T.; Kakehi, A.; Baba, T. J. Org.
Chem. 2011, 76, 7377. (m) Zhou, Y.-Y.; Wang, L.-J.; Li, J.; Sun, X.-
L.; Tang, Y. J. Am. Chem. Soc. 2012, 134, 9066.
1
2
3
4
5
6
7
8
(2) For recent reviews, see: (a) Lundgren, R. J.; Stradiotto, M. Angew.
Chem., Int. Ed. 2010, 49, 9322. (b) Furuya, T.; Kamlet, A. S.; Ritter,
T. Nature 2011, 473, 470. (c) Qing, F.-L.; Zheng, F. Synlett 2011,
1052. (d) Roy, S.; Gregg, B. T.; Gribble, G. W.; Le, V.-D.; Roy, S.
Tetrahedron 2011, 67, 2161. (e) Tomashenko, O. A.; Grushin, V. V.
Chem. Rev. 2011, 111, 4475. (f) Besset, T.; Schneider, C.; Cahard, D.
Angew. Chem., Int. Ed. 2012, 51, 5048.
(3) For reviews, see: (a) Mikami, K.; Itoh, Y.; Yamanaka, M. Chem. Rev.,
2004, 104, 1. (b) Shibata, N.; Mizuta, S.; Kawai, H. Tetrahedron:
Asymmetry 2008, 19, 2633. (c) Ma, J.-A.; Cahard, D. Chem. Rev.
2008, 108, PR1. (d) Nie, J.; Guo, H.-C.; Cahard, D.; Ma, J.-A. Chem.
Rev. 2011, 111, 455. (e) Valero, G.; Companyo, X.; Rios, R. Chem.-
Eur. J. 2011, 17, 2018.
(4) For reviews of catalytic asymmetric construction of all-carbon quater-
nary stereocenters, see: (a) Corey, E. J.; Guzman-Perez, A. Angew.
Chem., Int. Ed. 1998, 37, 388. (b) Douglas, C. J.; Overman, L. E.
Proc. Natl. Acad. Sci. U.S.A. 2004, 101, 5363. (c) Christoffers, J.;
Baro, A. Adv. Synth. Catal. 2005, 347, 1473. (d) Trost, B. M.; Jiang,
C. Synthesis 2006, 369. (e) Hawner, C.; Alexakis, A. Chem. Com-
mun. 2010, 46, 7295.
(5) (a) Deng, Q.-H.; Wadepohl, H.; Gade, L. H. J. Am. Chem. Soc. 2012,
134, 10769. (b) Kawai. H.; Okusu, S.; Tokunaga, E.; Sato, H.; Shiro,
M.; Shibata, N. Angew. Chem., Int. Ed. 2012, 51, 4959.
(6) For a book, see: (a) Bandini, M.; Umani-Ronchi, A. Catalytic Asym-
metric Friedel-Crafts Alkylations, Wiley-VCH, Weinheim, 2009. For
reviews, see: (b) Poulsen, T. B.; Jørgensen, K. A. Chem. Rev. 2008,
108, 2903. (c) You, S.-L.; Cai, Q.; Zeng, M. Chem. Soc. Rev. 2009,
38, 2190. (d) Bandini, M.; Eichholzer, A. Angew. Chem., Int. Ed.
2009, 48, 9608. (e) Terrasson, V.; Figueiredo, R. M.; Campagne, J.
M. Eur. J. Org. Chem. 2010, 2635.
(7) (a) Banwell, M. G.; Beck, D. A. S.; Willis, A. C. ARKIVOC 2006,
163. (b) Lyzwa, D.; Dudzinski, K.; Kwiatkowski, P. Org. Lett. 2012,
14, 1540.
(8) For selected examples, see: (a) Zhuang, W.; Hazell, R. G.; Jorgensen,
K. A. Org. Biomol. Chem. 2005, 3, 2566. (b) Herrera, R. P.;
Sgarrzani, V.; Bernardi, L.; Ricci, A. Angew. Chem., Int. Ed. 2005,
44, 6576. (c) Jia, Y.-X.; Zhu, S.-F.; Yang, Y.; Wang, L.-X.; Zhou,
Q.-L. J. Org. Chem. 2006, 71, 75. (d) Lu, S.-F.; Du, D.-M.; Xu, J.
Org. Lett. 2006, 8, 2115. (e) Ganesh, M.; Seidel, D. J. Am. Chem.
Soc. 2008, 130, 16464. (f) Itoh, J.; Fuchibe, K.; Akiyama, T. Angew.
Chem., Int. Ed. 2008, 47, 4016. (g) Yokoyama, N.; Arai, T. Chem.
Commun. 2009, 3285. (h) Mckeon, S. C.; Muller-Bunz, H.; Guiry, P.
J. Eur. J. Org. Chem. 2009, 4833. (i) Liu, H.; Du, D.-M. Adv. Syn.
Cat. 2010, 352, 1113. (j) Kim, H. Y.; Kim, S.; Oh, K. Angew. Chem.,
Int. Ed. 2010, 49, 4476. (k) Guo, F.; Lai, G.; Xiong, S.; Wang, S.;
Wang, Z. Chem. Eur. J. 2010, 16, 6438. (l) Takenaka, N.; Chen, J.;
Captain, B.; Sarangthem, R. S.; Chandrakumar, A. J. Am. Chem. Soc.
2010, 132, 4536. (m) Wu, J.; Li, X.; Wu, F.; Wan, B. Org. Lett.
2011, 13, 4834.
(14) Latest examples for the asymmetric Friedel-Crafts reaction with β-
CF3-α,β-unsaturated system as substrates to form tertiary
trifluoromethylated stereocenters: (a) Huang, Y.; Tokunaga, E.;
Suzuki, S.; Shiro, M.; Shibata, N. Org. Lett. 2010, 12, 1136. (b)
Blay, G.; Fernandez, I.; Munoz, M. C.; Pedro, J. R.; Vila. C. Chem.
Eur. J. 2010, 16, 9117. (c) Lin, J.-H.; Xiao, J.-C. Eur. J. Org. Chem.
2011, 4536. (d) Wang, W.; Lian, X.; Chen, D.; Liu, X.; Lin, L.; Feng,
X. Chem. Commun. 2011, 47, 7821. (e) Wen, L.; Shen, Q.; Wan, X.;
Lu, L. J. Org. Chem. 2011, 76, 2282. (f) Shibatomi, K.; Narayama,
A.; Abe, Y.; Iwasa, S. Chem. Commun. 2012, 48, 7380.
(15) Wahed, A. R.; Norbert, M. T.; Tesuya, M. PCT. Int. Appl,
2011128299, 20 Oct 2011.
(16) Nitroalkene 1g was determined to be E-configuration by X-ray anal-
ysis of its single crystal structure. The configurations of other sub-
strates were determined by analogy.
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
(17) No reaction occurred in the absence of a ligand or with 2,2’-
bipyridine as ligand.
(18) Liu, Y.-L.; Shi, T.-D.; Zhou, F.; Zhao, X.-L.; Wang, X.; Zhou, J. Org.
Lett. 2011, 13, 3826.
(9) (a) Trost, B. M.; Muller, C. J. Am. Chem. Soc. 2008, 130, 2438. (b)
Liu, H.; Lu, S.-F.; Xu, J.; Du, D.-M. Chem. Asian J. 2008, 3, 1111. (c)
Sheng, Y.-F.; Gu, Q.; Zhang, A-J.; You, S.-L. J. Org. Chem. 2009,
74, 6899. (d) Sheng, Y.-F.; Li, G.-Q.; Kang, Q.; Zhang, A-J.; You, S.-
L. Chem. Eur. J. 2009, 15, 3351. (e) Zhang, G. Org. Biomol. Chem.
2012, 10, 2534.
(10) Liu, H.; Xu, J.; Du, D.-M. Org. Lett. 2007, 9, 4725.
(11) (a) Liu, T.-Y.; Cui, H.-L.; Chai, Q.; Long, J.; Li, B.-J.; Wu, Y.; Ding,
L.-S.; Chen, Y.-C. Chem. Commun. 2007, 2228. (b) Sohtome, Y.;
Shin, B.; Horitsugi, N.; Takagi, R.; Nagasawa, K. Angew. Chem., Int.
Ed. 2010, 49, 7299.
(12) (a) Wu, J.; Mampreian, D. M.; Hoveyda, A. H. J. Am. Chem. Soc.
2005, 127, 4584. (b) Lu, H.-H.; Zhang, F.-G.; Meng, X.-G.; Duan, S.-
W.; Xiao, W.-J. Org. Lett. 2009, 11, 3946. (c) Zhang, F.-G.; Yang,
Q.-Q.; Xuan, J.; Lu, H.-H.; Duan, S.-W.; Chen, J.-R.; Xiao, W.-J.
Org. Lett. 2010, 12, 5636.
(13) Ni(ClO4)2 has been proved to be efficient catalysts in asymmetric
catalysis. For review, see: (a) Dalpozzo, R.; Bartoli, G.; Sambri, L.;
Melchiorre, P. Chem. Rev., 2010, 110, 3501. Selected examples: (b)
Kanemasa, S.; Oderaotoshi, Y.; Tanaka, J.; Wada, E. J. Am Chem.
Soc. 1998, 120, 12355. (c) Kanemasa, S.; Oderaotoshi, Y.; Sakaguchi,
S.; Yamamoto, H.; Tanaka, J.; Wada, E.; Curran, D. P. J. Am Chem.
Soc. 1998, 120, 3074. (d) Kanemasa, S.; Oderaotoshi, Y.; Wada, E. J.
Am Chem. Soc. 1999, 121, 8657. (e) Kanemasa, S.; Kanai, T. J. Am.
ACS Paragon Plus Environment

Page 5 of 5
Journal of the American Chemical Society
TOC
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
ACS Paragon Plus Environment