Enantioselective synthesis of planar chiral ferrocenes via palladium-catalyzed direct coupling with arylboronic acids

Article abstract of DOI:10.1021/ja311082u

Enantioselective Pd(II)-catalyzed direct coupling of aminomethylferrocene derivatives with boronic acids was realized. With commercially available Boc-l-Val-OH as a ligand, planar-chiral ferrocenes could be synthesized in yields of 14-81% with up to 99% ee under mild conditions.

Full text of DOI:10.1021/ja311082u

Subscriber access provided by FORDHAM UNIVERSITY
Communication
Enantioselective Synthesis of Planar Chiral Ferrocenes via
Palladium-catalyzed Direct Coupling with Aryl Boronic Acids
De-Wei Gao, Yan-Chao Shi, Qing Gu, Zheng Le Zhao, and Shu-Li You
J. Am. Chem. Soc., Just Accepted Manuscript • DOI: 10.1021/ja311082u • Publication Date (Web): 19 Dec 2012
Downloaded from http://pubs.acs.org on December 20, 2012
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
Enantioselective Synthesis of Planar Chiral Ferrocenes via Palla-
dium-catalyzed Direct Coupling with Aryl Boronic Acids
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
De-Wei Gao, Yan-Chao Shi, Qing Gu,* Zheng-Le Zhao, and Shu-Li You*
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences,
345 Lingling Lu, Shanghai 200032, P. R. of China
Supporting Information Placeholder
at 80 ℃ under air. To our great delight, the reaction proceeded
ABSTRACT: Enantioselective Pd(II)-catalyzed direct coupling
smoothly to afford the desired product 3a in 58% yield and 97% ee
along with trace amount of diarylation product 3a’ (entry 1, Table 1).
By adding 25 mol % TBAB (tetrabutyl ammonium bromide) as an
additive, the yield of product 3a could be further improved to 74%
without affecting the enantioselectivity (98% ee, entry 2, Table 1).
Next, commercially available N-Boc protected L-amino acids as
ligands were systematically examined. The results are summarized in
of aminomethyl ferrocene derivatives with boronic acids was
realized. With commercially available Boc-L-Val-OH as a ligand,
planar chiral ferrocenes could be synthesized in 14-81% yields
with up to 99% ee under mild conditions.
Table 1. The reactions all gave the desired product in yields ranging
Chiral ferrocenes are of great interest in the fields of asymmetric
catalysis, materials science, biomedical research, etc.1 Particularly,
from 48% to 75% and excellent ee values ranging from 81% to 98%
(entries 2-10, Table 1). Boc-L-Val-OH and Boc-L-Tle-OH proved to
ferrocenes bearing planar chirality, in some cases with additional
be the most efficient chiral ligands in terms of enantioselectivity and
central chirality, have been demonstrated highly efficient ligands or
catalysts in asymmetric catalysis.2 Consequently, the development of
reactivity, giving the desired product in 74-75% yield and 98% ee
(entries 2 and 8, Table 1). Boc-L-Val-OH was chosen for further
methods to introduce planar chirality into ferrocene backbone has
studies given its cheapness. The protecting groups on the nitrogen of
attracted intense attention. To date, the most widely used strategy is
diastereoselective directed ortho-metalation (DoM) induced by
various chiral auxiliaries (or chiral directing groups), and in this
L-valine were found to have dramatic impact on the reactivity and
enantioselectivity (Ac: 60% yield, 88% ee; Cbz: 52% yield, 96% ee;
approach a central chirality in general is required to be pre-installed.3
Fmoc: 19% yield; entries 11-13, Table 1). Lowering the reaction
temperature to 60 ℃ improved the yield slightly (79% yield, entry
Notably, Snieckus et al developed an enantioselective DoM of
14, Table 1). Notably, there is a moderate kinetic resolution for the
ferrocene derivatives with an external chiral base such as (-)-
formation of bisphenylation product 3a’. Along with the reaction
time, both the ratio of bisphenylation byproduct 3a’ and the ee of 3a
increased slightly (for details, see the SI). Further screening other
reaction parameters including oxidant, base, solvent, catalyst loading
and the amount of phenyl boronic acid did not improve the results
(for details, see the SI). Thus the optimized conditions were obtained
as the following: 10 mol % Pd(OAc)2, 20 mol % Boc-L-Val-OH, 2
equiv of boronic acid, 1 equiv of K2CO3 and 25 mol % TBAB in
DMA at 60 ℃ under air (entry 14, Table 1).
sparteine, which provides a straightforward route to ferrocenes with
only planar chirality.4 Recently, Ogasawara et al reported an elegant
method to synthesize planar chiral ferrocenes through ring-closing
metathesis reactions.5 However, the catalytic enantioselective
synthesis of planar chiral ferrocenes remains rare.6 Developing such
a process with readily available starting materials and catalysts is
challenging but highly desirable.
Palladium-catalyzed direct functionalization of inert C-H bonds
has witnessed significant progress during the past decade.7 Despite
the continuous efforts, catalytic enantioselective C-H activation as a
highly challenging topic progressed rather slowly.8 Breakthroughs
recently have been achieved by Yu and coworkers9 who discovered
chiral monoprotected amino acids as efficient ligands to enable
enantioselective C-H activation of series of prochiral substrates.
Inspired by these results, we recently explored the enantioselective
synthesis of planar chiral ferrocenes as our ongoing program towards
direct functionalization of ferrocenes.10-11 The commercially avail-
able amino acid derivatives were found to be highly efficient ligands
for Pd-catalyzed direct functionalization of ferrocene with boronic
acids. The conditions developed tend to be mild, general and practi-
cal for the synthesis of enantiopure planar chiral ferrocenes. In this
paper, we report such a highly enantioselective synthesis of planar
chiral ferrocenes via Pd-catalyzed C-H bond activation process.
We began our studies by using dimethylaminomethyl ferrocene
(1a) as a model substrate. Pd-catalyzed direct arylation of 1a with
phenylboronic acid12 was then carried out in the presence of 10 mol
% Pd(OAc)2, 20 mol % Boc-L-Val-OH and 1 equiv K2CO3 in DMA
ACS Paragon Plus Environment

Journal of the American Chemical Society
Page 2 of 5
Table 1. Screening protected amino acids a
97% ee (entry 14, Table 2). The wide tolerance of substituents
1
2
3
4
5
6
7
provided the opportunity for further transformation of the products
into useful ligands or catalysts.
NMe2
NMe2
NMe2
Ph
Pd(OAc)2 (10 mol %)
ligand (20 mol %)
Ph
Ph
+
PhB(OH)2 (2a) (2 equiv)
K2CO3 (1 equiv)
Fe
Fe
Fe
Table 2. Enantioselective synthesis of planar chiral ferro-
cene via C-H activation a
TBAB (0.25 equiv)
DMA, 80 oC, air, 4h
1a
3a
3a'
8
9
Yield
(%)c
Ee
Entry
Ligand
3a:3a’b
(%)d
97
98
98
94
92
96
97
98
96
81
88
96
-
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
1e
2
Boc-L-Val-OH
Boc-L-Val-OH
Boc-L-Phe-OH
Boc-L-Abu-OH
Boc-L-Ala-OH
Boc-L-Leu-OH
Boc-L-Ile-OH
Boc-L-Tle-OH
Boc-L-Nva-OH
Boc-L-Phg-OH
Ac-L-Val-OH
Cbz-L-Val-OH
Fmoc-L-Val-OH
Boc-L-Val-OH
Boc-L-Val-OH
42:1
8.3:1
8.7:1
10:1
4.2:1
20:1
9.5:1
9:1
58
74
71
64
61
51
70
75
69
48
60
52
19b
79
59
3
Time
(h)
Yield
(%)b
Entry
R3 (2)
Ee(%)c
1
4
1
2
3
4
5
6
7
8
9
C6H5 (2a)
10
10
10
75
10
3.5
10
10
10
79 (3a)
70 (3b)
81 (3c)
33 (3d)
59 (3e)
75 (3f)
72 (3g)
55 (3h)
61 (3i)
98
97
99
94
96
96
97
97
94
1a
1a
1a
1a
1a
1a
1a
1a
1a
5
4-MeC6H4 (2b)
3-MeC6H4 (2c)
2-MeC6H4 (2d)
4-MeOC6H4 (2e)
2-naphthyl (2f)
4-ClC6H4 (2g)
4-FC6H4 (2h)
4-CF3C6H4 (2i)
6
7
8
9
6.4:1
6.5:1
10:1
25:1
-
10
11
12
13
14f
15g
4-EtOCOC6H4
10
8
72 (3j)
95
1a
(2j)
11d
12
Me (2k)
24
22
14 (3k)
67 (3l)
ND
90
1a
1b
20:1
50:1
98
97
C6H5 (2a)
71
13
C6H5 (2a)
C6H5 (2a)
10
16
98
97
1c
a
(3m)
Reaction conditions: 1a (0.2 mmol), 2a (0.4 mmol), Pd(OAc)2
(10 mol %), ligand (20 mol %), K2CO3 (1 equiv), TBAB (0.25 equiv)
in DMA at 80 ℃ under air. Determined by H NMR with CH2Br2
14
69 (3n)
1d
b
1
a
c
d
Reaction conditions: 1 (0.2 mmol), 2 (0.4 mmol), Pd(OAc)2
as an internal standard. Isolated yield. Determined by HPLC
analysis. e Without TBAB. f At 60 ℃. g At 40 ℃.
(10 mol %), Boc-L-valine (20 mol %), K2CO3 (1 equiv), TBAB
b
c
(0.25 equiv) in DMA at 60 ℃ under air. Isolated yield. Deter-
mined by HPLC analysis. d At 90 ℃.
Under the above optimized reaction conditions, various ami-
nomethyl ferrocene derivatives and boronic acids were examined to
test the generality of the current reaction. The results are summarized
in Table 2. Various substituted aryl boronic acids bearing either an
electron-donating group or an electron-withdrawing group were well
tolerated and led to their corresponding products in good yields and
excellent ee values (55-81% yields, 94-99% ee, entries 2-3, 5, 7-10,
Table 1) except for ortho-methyl phenylboronic acid 2b (33% yield,
94% ee, entry 4, Table 2). Notably, the reaction with 2-naphthyl
boronic acid also led to product 3f in 75% yield and 96% ee (entry 6,
Table 2). The reaction of alkyl boronic acid required higher tempera-
ture in prolonged reaction time, giving the desired product in a
moderate yield (entry 11). In addition, the reaction was general for
ferrocenes with different alkyl group on nitrogen atom (NEt2, 67%
yield, 90% ee; N-(CH2)4-, 71% yield, 98% ee; entries 12-13, Table
2). Introduction of a substituent on another Cp ring could also be
tolerated. For instance, when 1-aminomethyl 1’-bromo ferrocene (1d)
was used, the arylation product 3n was obtained in 69% yield and
The absolute configuration of the product 3a was assigned as (Sp)
by comparing the optical rotation of the same compound, which was
transformed from either 3a or a compound reported in the literature
with known absolute configuration (for details, see the SI).
To test the practicality of the methodology, a relatively large scale
reaction was carried out. The arylation of ferrocene 1a in a 2 mmol
scale with phenylboronic acid (2a) afforded the desired product
[(Sp)-3a] without notable erosions in both yield and enantioselectiv-
ACS Paragon Plus Environment

Page 3 of 5
Journal of the American Chemical Society
rahedron: Asymmetry 1998, 9, 2377. (d) Fu, G. C. Acc. Chem. Res.
ity (73% yield, 98% ee, eq 1). However, addition of phenylboronic
2000, 33, 412. (e) Dai, L.-X.; Tu, T.; You, S.-L.; Deng, W.-P.; Hou,
X.-L. Acc. Chem. Res. 2003, 36, 659. (f) Colacot, T. J. Chem. Rev.
2003, 103, 3101. (g) Fu, G. C. Acc. Chem. Res. 2004, 37, 542. (h)
Arrayás, R. G.; Adrio, J.; Carretero, J. C. Angew. Chem., Int. Ed.
2006, 45, 7674. (i) Fu, G. C. Acc. Chem. Res. 2006, 39, 853. (j) Arae,
S.; Ogasawara, M. J. Syn. Org. Chem. 2012, 70, 593.
Selected examples: (a) Battelle, L. F.; Bau, R.; Gokel, G. W.; Oya-
kawa, R. T.; Ugi, I. K. J. Am. Chem. Soc. 1973, 95, 482. (b) Gokel,
G. W.; Marquarding, D.; Ugi, I. K. J. Org. Chem. 1972, 37, 3052. (c)
Rebière, F.; Riant, O.; Ricard, L.; Kagan, H. B. Angew. Chem., Int.
Ed. 1993, 32, 568. (d) Riant, O.; Samuel, O.; Kagan, H. B. J. Am.
Chem. Soc. 1993, 115, 5835. (e) Richards, C. J.; Damalidis, T.;
Hibbs, D. E.; Hursthouse, M. B. Synlett 1995, 74. (f) Riant, O.;
Samuel, O.; Flessner, T.; Taudien, S.; Kagan, H. B. J. Org. Chem.
1997, 62, 6733. (g) Enders, D.; Peters, R.; Lochtman, R.; Raabe, G.
Angew. Chem., Int. Ed. 1999, 38, 2421.
Selected examples: (a) Tsukazaki, M.; Tinkl, M.; Roglans, A.;
Chapell, B. J.; Taylor, N. J.; Snieckus, V. J. Am. Chem. Soc. 1996,
118, 685. (b) Laufer, R. S.; Veith, U.; Taylor, N. J.; Snieckus, V.
Org. Lett. 2000, 2, 629.
(a) Ogasawara, M.; Watanabe, S.; Fan, L.; Nakajima, K.; Takahashi,
T. Organometallics 2006, 25, 5201. (b) Ogasawara, M.; Watanabe,
S.; Nakajima, K.; Takahashi, T. J. Am. Chem. Soc. 2010, 132, 2136.
For reviews: (c) Ogasawara, M.; Watanabe, S.; Nakajima, K.;
Takahashi, T. Pure Appl. Chem. 2008, 80, 1109. (d) Ogasawara, M.;
Watanabe, S. Synthesis 2009, 1761.
1
2
3
4
5
6
7
8
acid in five times (every two hours) has a beneficial effect for
achieving a higher yield comparing with one-time addition.
As a further demonstration of the utility of our methodology, pla-
nar chiral P, N-ligand L1 was prepared from product 3n obtained in
the current study. Starting from 3n (96% ee), lithiation with n-BuLi
followed by quenching with Ph2PCl afforded L1 in 68% yield and
92% ee (eq 2). A preliminary examination of L1 (92% ee) in palla-
dium-catalyzed allylic alkylation reaction disclosed that this type of
P, N-ligand is highly efficient although the enantioselectivity needs
further improvement (98% yield, 15% ee, eq 3).
3.
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
4.
5.
6.
7.
For a review on kinetic resolution with enzymes: (a) Alba, Andrea-
Nekane R.; Rios, R. Molecules 2009, 14, 4747. For selected catalyti-
cally asymmetric synthesis: (b) Siegel, S.; Schmalz, H.-G. Angew.
Chem., Int. Ed. 1997, 36, 2456. (c) Genet, C.; Canipa, S. J.; O’Brien,
P.; Taylor, S. J. Am. Chem. Soc. 2006, 128, 9336. (d) Bueno, A.;
Rosol, M; García, J.; Moyano, A. Adv. Synth. Catal. 2006, 348, 2590.
(e) Alba, A.-N.; Pilar Gómez-Sal, P.; Rios, R.; Moyano, A.
Tetrahedron: Asymmetry 2009, 20, 1314.
In summary, we have developed an asymmetric Pd-catalyzed
direct functionalization of aminomethyl ferrocene derivatives with
boronic acids. The new methodology provides a highly enantioselec-
tive synthesis of planar chiral ferrocenes from readily available
starting materials under mild reaction conditions. The requirement of
commercially available and cheap N-Boc-protected amino acids as
efficient ligands and air as oxidant makes the current access to
enantiopure ferrocene compounds potentially practical. Further
mechanistic investigations, application of these enantiopure ferro-
cenes and development of more efficient catalytic system are
currently underway in our laboratory.
Selected reviews: (a) Daugulis, O.; Zaitsev, V. G.; Shabashov, D.;
Pham, Q. N.; Lazareva, A. Synlett 2006, 3382. (b) Campeau, L. C.;
Fagnou, K. Chem. Commun. 2006, 1253. (c) Li, B.-J.; Yang, S.-D.;
Shi, Z.-J. Synlett 2008, 949. (d) Chen, X.; Engle, K. M.; Wang, D.-
H.; Yu, J.-Q. Angew. Chem., Int. Ed. 2009, 48, 5094. (e) Daugulis,
O.; DO, H.-Q. Shabashov, D. Acc. Chem. Res. 2009, 42, 1074. (f)
Yu, J.-Q.; Shi, Z.-J. Top. Curr. Chem. 2010, 292. (g) Sun, C.-L.; Li,
B.-J.; Shi, Z.-J. Chem. Commun. 2010, 46, 677. (h) Lyons, T. W.;
Sanford, M. S. Chem. Rev. 2010, 110, 1147. (i) Sehnal, P.; Taylor, R.
J. K.; Fairlamb, I. J. S. Chem. Rev. 2010, 110, 824. (j) Engle, K. M.;
Mei, T.-S.; Wasa, M.; Yu, J.-Q. Acc. Chem. Res. 2012, 45, 788. (k)
Neufeldt, S. R.; Sanford, M. S. Acc. Chem. Res. 2012, 45, 936.
For reviews: (a) Giri, R.; Shi, B.-F.; Engle, K. M.; Maugel, N.; Yu,
J.-Q. Chem. Soc. Rev. 2009, 38, 3242. (b) Peng, H. M.; Dai, L.-X.;
You, S.-L. Angew. Chem., Int. Ed. 2010, 49, 5826. For selected ex-
amples: (c) Mikami, K.; Hatano, M.; Terada, M. Chem. Lett. 1999,
28, 55. (d) Kakiuchi, F.; Le Gendre, P.; Yamada, A.; Ohtaki, H.;
Murai, S. Tetrahedron: Asymmetry 2000, 11, 2647. (e) Thalji, R. K.;
Ellman, J. A.; Bergman, R. G. J. Am. Chem. Soc. 2004, 126, 7192. (f)
Albicker, M. R.; Cramer, N. Angew. Chem., Int. Ed. 2009, 48, 9139.
(g) Renaudat, A.; Jean-Gérard, L.; Jazzar, R.; Kefalidis, C. E.; Clot,
E.; Baudoin, O. Angew. Chem., Int. Ed. 2010, 49, 7261. (h)
Nakanishi, M.; Katayev, D.; Besnard, C.; Kündig E. P. Angew.
Chem., Int. Ed. 2011, 50, 7438. (i) Anas, S.; Cordi, A.; Kagan, H. B.
Chem. Commun. 2011, 47, 11483. (j) Katayev, D.; Nakanishi, M.;
Bürgib, T.; Kündig, E. P. Chem. Sci. 2012, 3, 1422. (k) Saget, T.;
Lemouzy, S. J.; Cramer, N. Angew. Chem., Int. Ed. 2012, 51, 2238.
(l) Martin, N.; Pierre, C.; Davi, M.; Jazzar, R.; Baudoin, O. Chem.
Eur. J. 2012, 18, 4480. (m) Yamaguchi, K.; Yamaguchi, J.; Studer,
A.; Itami, K. Chem. Sci. 2012, 3, 2165. (n) Shintani, R.; Otomo, H.;
Ota, K.; Hayashi, T. J. Am. Chem. Soc. 2012, 134, 7305. (o) Saget,
T.; Cramer, N. Angew. Chem., Int. Ed. 2012, 51, 12842.
ASSOCIATED CONTENT
Supporting Information
8.
Experimental procedures and analysis data for all new compounds.
This material is available free of charge via the Internet at
http://pubs.acs.org.
AUTHOR INFORMATION
Corresponding Author
qinggu@sioc.ac.cn or slyou@sioc.ac.cn
ACKNOWLEDGMENT
We thank the National Basic Research Program of China (973
Program 2009CB825300) and National Natural Science Founda-
tion of China (20923005, 21025209, 21002111, 21121062) for
generous financial support.
REFERENCES
9.
(a) Shi, B.-F.; Maugel, N.; Zhang, Y.-H.; Yu, J.-Q. Angew. Chem.,
Int. Ed. 2008, 47, 4882. (b) Shi, B.-F.; Zhang, Y.-H.; Lam, J. K.;
Wang, D.-H.; Yu, J.-Q. J. Am. Chem. Soc. 2010, 132, 460. (c) Wasa,
M.; Engle, K. M.; Lin, D. W.; Yoo, E. J.; Yu, J.-Q. J. Am. Chem. Soc.
2011, 133, 19598. (d) Musaev, D. G.; Kaledin, A.; Shi, B.-F.; Yu, J.-
Q. J. Am. Chem. Soc. 2012, 134, 1690.
1.
For books see: (a) Hayashi, T., Togni, A., Eds. Ferrocenes; VCH:
Weinheim, Germany, 1995. (b) Togni, A., Haltermann, R. L., Eds.
Metallocenes; VCH: Weinheim, Germany, 1998. (c) Štěpnička, P.,
Ed. Ferrocenes; Wiley: Chichester, 2008. (d) Dai, L.-X.; Hou, X.-L.,
Eds. Chiral Ferrocenes in Asymmetric Catalysis, Wiley: 2010.
(a) Halterman, R. L. Chem. Rev. 1992, 92, 965. (b) Togni, A. Angew.
Chem. Int. Ed. 1996, 35, 1475. (c) Richards, C. J.; Locke, A. J. Tet-
10. For enantioselective studies: (a) Xia, J.-B.; You, S.-L. Organometal-
lics 2007, 26, 4869. (b) Günay, M. E.; Richards, C. J. Organometal-
2.
ACS Paragon Plus Environment

Journal of the American Chemical Society
Page 4 of 5
lics 2009, 28, 5833. (c) Dendele, N.; Bisaro, F.; Gaumont, A.-C.;
Perriob, S.; Richards, C. J. Chem. Commun. 2012, 48, 1991. (d) Ta-
kebayashi, S.; Shizuno, T.; Otani, T.; Shibata, T. Beilstein J. Org.
Chem. 2012, 8, 1844. For an early study on amino acid assisted C-H
activation of ferrocene in the presence of palladium(II) salt: (e)
Sokolov, V. I.; Troitskaya, L. L.; Reutov, O. A. J. Organomet. Chem.
1979, 182, 537.
1
2
3
4
5
6
7
8
11. Selected recent racemic studies: (a) Takebayashi, S.; Shibata, T.
Organometallics 2012, 31, 4114. (b) Zhang, H.; Cui, X.; Yao, X.;
Wang, H.; Zhang, J.; Wu, Y. Org. Lett. 2012, 14, 3012. (c) Singh, K.
S.; Dixneuf, P. H. Organometallics 2012, 31, 7320.
12. For book and reviews on direct arylation with boronic acid: (a)
Ackermann, L. Eds. Modern Arylation Methods Wiley: 2009. (b)
Alberico, D.; Scott, M. E.; Lautens, M. Chem. Rev. 2007, 107, 174.
(c) Ackermann, L.; Vicente, R.; Kapdi, A. R. Angew. Chem., Int. Ed.
2009, 48, 9792. Selected examples: (d) Chen, X.; Goodhue, C. E.;
Yu, J.-Q. J. Am. Chem. Soc. 2006, 128, 12634. (e) Giri, R.; Maugel,
N.; Li, J.-J.; Wang, D.-H.; Breazzano, S. P.; Saunders, L. B.; Yu, J.-
Q. J. Am. Chem. Soc. 2007, 129, 3510. (f) Shi, Z.; Li, B.; Wan, X.;
Cheng, J.; Fang, Z.; Cao, B.; Qin, C.; Wang, Y. Angew. Chem., Int.
Ed. 2007, 46, 5554. (g) Yang, S.-D.; Sun, C.-L.; Fang, Z.; Li, B.-J.;
Li, Y.-Z.; Shi, Z.-J. Angew. Chem., Int. Ed. 2008, 47, 1473. (h)
Wang, D.-H.; Mei, T.-S.; Yu, J.-Q. J. Am. Chem. Soc. 2008, 130,
17676. (i) Wen, J.; Zhang, J.; Chen, S.-Y.; Li, J.; Yu, X.-Q. Angew.
Chem., Int. Ed. 2008, 47, 8897. (j) Wei, Y.; Kan, J.; Wang, M.; Su,
W.; Hong, M. Org. Lett. 2009, 11, 3346. (k) Engle, K. M.; Thuy-
Boun, P. S.; Dang, M.; Yu, J.-Q. J. Am. Chem. Soc. 2011, 133,
18183.
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

Page 5 of 5
Journal of the American Chemical Society
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