Practical Cross-Coupling between O-Based Electrophiles and Aryl Bromides via Ni Catalysis

Article abstract of DOI:10.1021/acs.orglett.6b02656

Cross-coupling of various O-based electrophiles with aryl bromides was developed through Ni-catalyzed C-O activation in the presence of magnesium. Beside carboxylates, carbamates, and ethers, phenols exhibited excellent reactivity under modified conditions. This chemistry was featured as a simple and environmentally benign process with low catalyst loading and easy manipulations. The method exhibited broad substrate scopes.

Full text of DOI:10.1021/acs.orglett.6b02656

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Letter
pubs.acs.org/OrgLett
Practical Cross-Coupling between O‑Based Electrophiles and Aryl
Bromides via Ni Catalysis
Zhi-Chao Cao,†,§ Qin-Yu Luo,†,§ and Zhang-Jie Shi*,†,‡
†Beijing National Laboratory of Molecule Science (BNLMS) and Key Laboratory of Bioorganic Chemistry and Molecular
Engineering of Ministry of Education, College of Chemistry and Green Chemistry Centre, Peking University, Beijing 100871, China
‡State Key Laboratory of Organometallic Chemistry, Chinese Academy of Science, Shanghai 200032, China
S
* Supporting Information
ABSTRACT: Cross-coupling of various O-based electrophiles with aryl bromides was
developed through Ni-catalyzed C−O activation in the presence of magnesium. Beside
carboxylates, carbamates, and ethers, phenols exhibited excellent reactivity under modified
conditions. This chemistry was featured as a simple and environmentally benign process with
low catalyst loading and easy manipulations. The method exhibited broad substrate scopes.
ransition-metal-catalyzed cross-coupling has become one
and PCy3 was efficient to carry out the cross-coupling between
Tof the most powerful tools to construct carbon−carbon 1a and the prepared Grignard reagent 2a′ (eq 1).7n,o,10 We first
bonds in organic synthesis since the 1970s.1 Much attention has
been paid to the preparation of the biaryl skeleton through
cross-couplings due to its versatile application in pharmaceut-
icals, material chemistry, and total synthesis of natural
products.2 At the early stage of development, aryl halides and
their equivalents were successfully employed as electrophiles to
construct biaryl scaffolds.3 Recently, O-based electrophiles have
been used as alternatives to organic halides.4 To date,
carbamates,5 carboxylates,6 ethers,6c,7 and so on have been
submitted the substrates 1a and 2a to the corresponding
successfully applied in various coupling reactions to construct
C−C as well as C−heteroatom bonds. Sporadic cases
employing phenols and alcohols as electrophiles have also
been reported.8
conditions in the presence of Mg. Unfortunately, the desired
product 3aa was not observed (eq 2) (see the SI for control
experiments). This result indicated that a simple extension of
the previously developed Kumada-type coupling of O-based
electrophiles was not suitable for the development of targeted
reductive coupling between aryl ethers and aryl halides.
After systematic investigations of reaction parameters (Table
1), we found that a cocktail containing Ni(COD)2, ItBu, and
Mg promoted the desired cross-coupling at 60 °C in THF for
24 h to give 3aa in 88% yield (entry 1). Control experiments
indicated the crucial roles of either Ni catalyst or Mg (entries
2−4). As expected, the ligand proved to be essential. When
other N-heterocyclic carbene ligands, such as IMes, IPr, IAd,
ICy(HCl), and SItBu(HCl), were used instead of ItBu, IAd
ICy(HCl), and SItBu(HCl), 3aa was obtained in good yields
(entries 5−9). When ICy(HCl) and SItBu(HCl) were used,
MeMgBr was required as a deprotonating reagent (entries 8−
9). Other reductants were also tested, and no desired product
was observed (entries 10 and 11). Nonpolar solvent, such as
toluene, was not suitable for the transformation (entry 12). 4-
Chlorotoluene and 4-iodotoluene were used to take place the of
2a, the desired product 3aa was not observed at all, and the
starting material 1a was completely recovered (entries 13 and
14).
A major disadvantage of the widespread application of the
cross-coupling reactions is the employment of prepared
organometallic reagents, for example, Grignard reagents,
which are not only costly stepwise but also sensitive to
moisture and air.1 The cross-coupling between two electro-
philes is an alternative method to circumvent this problem.6j,k,9
Among recent advancements of cross-coupling between two
electrophiles, an important pathway is to generate the active
organometallic reagents in situ by avoiding the tedious
preparations and complex manipulations of organometallic
reagents. Recently, the elegant example of iron-catalyzed
selective cross-coupling between aryl halides and alkyl halides
was reported in the presence of magnesium.9d Cross-coupling
of nonactivated alkyl tosylates and mesylates with alkyl and aryl
bromides was also approached via Cu catalysis.9i In this paper,
we demonstrated cross-coupling of arenol and their derivatives
with aryl bromides to construct biaryl scaffolds through Ni-
catalyzed C−O activation in the presence of magnesium under
mild conditions. Under these conditions, vinyl and benzyl
ethers also exhibited credible reactivity.
Our initial study was set to evaluate the cross-coupling
between naphthyl methyl ether (1a) and aryl bromide (2a).
Previous reports indicated that the combination of Ni(COD)2
Received: September 4, 2016
© XXXX American Chemical Society
A
DOI: 10.1021/acs.orglett.6b02656
Org. Lett. XXXX, XXX, XXX−XXX

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Table 1. Investigation of Different Parameters in the Cross-
a
Coupling of 1a and 2a
entry
1
ligand (L)
reductant (M)
solvent
yield (%)
ItBu
ItBu
Mg
Mg
Mg
THF
THF
THF
THF
THF
THF
THF
THF
THF
THF
THF
toluene
THF
THF
92 (88)
b
2
0
0
3
4
5
6
7
ItBu
0
IAd
Mg
Mg
Mg
Mg
Mg
Zn
65
0
IMes
IPr
Figure 2. Nickel-catalyzed cross-coupling of naphthylmethyl ether 1a
with different organo bromides 2. Conditions: aryl methyl ether (0.2
mmol), organo bromide (0.3 mmol), Ni(COD)2 (5.0 mol %), ItBu (20
mol %), Mg (3.6 equiv), THF (1.0 mL), 60 °C, 24 h. Isolated yields
are reported on the basis of aryl methyl ether. 0.6 mmol organo
bromide was used.
0
c
8
c
ICy(HCl)
SItBu(HCl)
ItBu
82
87
0
9
10
11
12
ItBu
Mn
Mg
Mg
Mg
0
ItBu
0
d
13
e
ItBu
0
and products untouched. This result indicated that different
aryl C−O bonds could be discriminated under the reaction
conditions, providing the opportunity for orthogonal cross-
coupling to produce more complex molecules.7n Moreover, aryl
bromide bearing an N,N-dimethylamino group was suitable to
produce the desired product 3ah in an excellent yield. As
expected, multisubstituted aryl bromides (3ai and 3aj) proved
to be suitable in this catalytic system. It is important to note
that the electronic property of aryl bromides played a vital role,
and aryl bromides bearing a strong electron-withdrawing group,
for example, trifluoromethyl (3ak), failed to facilitate this
coupling. Analysis of the reaction mixture indicated the
homocoupling of aryl bromides occurred.
14
ItBu
0
a
1a (0.2 mmol), 2a (0.3 mmol), Ni(COD)2 (5.0 mol %), ligand (20
mol %), Mg (3.6 equiv), THF (1.0 mL), 60 °C, 24 h. NMR yields
were reported based on 1a, and benzo[d][1,3]dioxole was used as the
inner standard; isolated yield is reported in the parentheses. Ni(cod)2
was omitted. MeMgBr (0.04 mmol) was used to deprotonate the
NHC(HCl). 4-Chlorotoluene was used to instead of 2a. 4-
Iodotoluene was used to instead of 2a. Abbreviations: ItBu = 1,3-di-
tert-butylimidazol-2-ylidene; IAd = 1,3-bis(1-adamantyl)imidazol-2-
ylidene; IMes =1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene; IPr
= 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene; ICy(HCl) = 1,3-
dicyclohexylimidazolium chloride; SItBu(HCl) = 1,3-di-tert-butylimi-
dazolinium chloride.
b
c
d
e
Subsequently, different methyl naphthyl ethers were system-
atically investigated (Figure 3). Obviously, alkyl and aryl groups
Under optimized conditions, we tested the reactivity of
different 2-naphthol derivatives (Figure 1). Other ethers, such
Figure 1. Nickel-catalyzed cross-coupling of 2a with various 2-
naphthol derivatives. Conditions: 1, 4−8 (0.2 mmol), 2a (0.3 mmol),
Ni(COD)2 (5.0 mol %), ItBu (20 mol %), Mg (3.6 equiv), THF (1.0
mL), 60 °C, 24 h NMR yields are reported on the basis of 1a, and
benzo[d][1,3]dioxole was used as the inner standard.
Figure 3. Nickel-catalyzed cross-coupling of 2a with aryl methyl ethers
1. Conditions: aryl methyl ether (0.2 mmol), organo bromide (0.3
mmol), Ni(COD)2 (5.0 mol %), ItBu (20 mol %), Mg (3.6 equiv),
THF (1.0 mL), 60 °C, 24 h. Isolated yields are reported on the basis of
aryl methyl ether. (a) 0.6 mmol organo bromide was used. (b) NMR
yield is reported. (c) Ni(cod)2 (10 mol %), ItBu (40 mol %), p-TolBr
(3.0 equiv).
as isopropyl ether (4), proved to be suitable substrates and
transformed into the desired product 3aa in quantitative yield.
To our delight, the success of carboxylate (5) and carbamate
(6) further indicated the power of this reaction. Unfortunately,
unprotected 2-naphthol (7) was not suitable under the current
conditions.
Various organo bromides were further examined carefully
(Figure 2). The cross-coupling with aryl bromides 2 bearing
different alkyl groups proceeded smoothly, and the correspond-
ing products 3 were afforded in good to excellent yields (3aa−
af). In comparison, the steric hindrance (3af) decreased the
efficiency, while an excellent yield could also be reached with
3.0 equiv of 2f. To our delight, methoxy-substituted phenyl
bromides (3ag and 3aj) were successfully applied as coupling
partners, leaving the MeO− group in both starting materials
at the 6-position did not affect the efficiency (3ba and 3ea),
while a cyclopropyl substituent (3ca) led to a lower yield albeit
the 3-membered ring was untouched. The aliphatic etheric
group (3da) survived well. Similarly, the N,N-dialkylamino
group was also compatible (3ga). Notably, the trimethylsilyl
group survived under the reaction conditions (3fa). As for its
coupling partner, the steric hindrance is critical for this
coupling. For example, the efficiency of 1-naphthyl methyl
ether (3ia) gave a lower efficacy. When methyl group was
introduced at the ortho-position of 2-naphthyl ethers (3ha), the
B
DOI: 10.1021/acs.orglett.6b02656
Org. Lett. XXXX, XXX, XXX−XXX

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coupling efficiency dramatically decreased while the same
strategy (with 3.0 equiv of aryl bromides) could promote the
efficiency. It is noteworthy that the methoxyl groups at both the
α- and β-positions could be coupled with aryl bromide under
the same conditions (3ja). Notably, the biphenyl substrate 1k
was also transformed to the corresponding product 3ka
although in a lower isolated yield. To our delight, the
developed methodology was also suitable for the arylation of
vinyl methyl ether, and desired product 3la was obtained in an
acceptable yield.
delight, when we changed the conditions with the use of mixed
toluene/THF (volume ratio: 3/1) to take the place of THF and
increased the amount of both catalysts and magnesium, the
desired product 3aa was obtained directly from 2-naphthol 1a
in an excellent yield. Arenols bearing different alkyl
substituents, including primary alkyl group (3ba), secondary
alkyl groups (3ca, 3pa, and 3qa), and tertiary alkyl group (3ra),
were transformed to the targeted corresponding products in
high yields. Besides the alkyl group, arenol bearing an aryl
substituent proved to be suitable (3ea). As anticipated, sp3 C−
O survived well under the modified conditions (3sa). To our
delight, when the substrate containing acetal was submitted to
the system, the desired product 3ta was furnished in high
efficiency.
Inspired by the success of cross-coupling between aryl ethers
and aryl bromides, sp3 O-based electrophiles were considered
(Scheme 1). We tested primary benzyl methyl ether (1m), and
We set out to explore the mechanism of this cross-coupling
reaction. A series of control experiments were conducted, and
they revealed that this cross-coupling is not a simple
combination of Kumada cross-coupling and Grignard reagent
formation. Furthermore, a mercury poisoning test was
performed, and the result indicated that a heterogeneous
species may be involved in the catalytic cycle. Data collected
from radical-capture experiments suggested that radical species
may participate in the catalytic cycle (for detailed mechanistic
information, see the Supporting Information).
Scheme 1. Nickel-Catalyzed Cross-Coupling of Different
Benzyl Methyl Ethers and Organobromide 2a
In summary, we demonstrated the cross electrophile
coupling between aryl ethers and aryl bromides via nickel
catalysis in the presence of Mg as reductant. Aryl carboxylates
and carbamates were suitable under standard conditions. Vinyl
ethers and benzyl ether derivatives were efficient for the
coupling. Under modified conditions, arenols were efficiently
applied as coupling partners. This methodology is featured as a
simple, robust process to forge carbon−carbon bonds
efficiently. Continuous efforts to expand substrate scopes and
to understand the detailed mechanism are underway.
to our delight, the corresponding cross coupling took place
smoothly and the desired product (3ma) was obtained in a
quantative isolated yield (Scheme 1a). Besides primary 2-
naphthyl methyl ether 1m, the secondary carbon-centered ether
(1n), which presents β-H, was also suitable, and the desired
product (3na) was isolated. Notably, if the enantiopure
substrate (1o) was submitted, the stereospecific cross-coupling
occurred and the enantiopure product 3oa was isolated in an
excellent yield by keeping the ee value at the same level
(Scheme 1b). The conversion of the absolute configuration of
the stereogenic center implied that the oxidative addition of
nickel catalyst to the C−O bond may proceed through the SN2-
type pathway; similar reactivity was also reported by the Jarvo
group.4g
Compared to anisole derivatives, arenols are relatively cheap
and easily available. However, because of its kinetic and
thermodynamical stability, it is more challenging to directly
apply arenols for the cross-coupling.11 As mentioned above,
cross-coupling of 2-naphthol 1a with 4-toluyl bromide 2a failed
under the above conditions. Because of its potential application
and fundamental challenges, we set out to evaluate direct cross-
coupling between arenols and aryl halides (Figure 4). To our
ASSOCIATED CONTENT
■
S
* Supporting Information
The Supporting Information is available free of charge on the
ACS Publications website at DOI: 10.1021/acs.or-
glett.6b02656.
Experimental procedures and characterization data of
products (PDF)
AUTHOR INFORMATION
■
Corresponding Author
*E-mail: zshi@pku.edu.cn.
ORCID
Zhang-Jie Shi: 0000-0002-0919-752X
Author Contributions
§Z.-C.C. and Q.-Y.L. contributed equally to this work.
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
Figure 4. Nickel-catalyzed cross-coupling of organo bromide 2a with
various arenols. Conditions: phenol (0.2 mmol), organo bromide (0.6
mmol), Ni(COD)2 (10.0 mol %), ItBu (40 mol %), Mg (5.0 equiv),
PhMe/THF (0.45 mL + 0.15 mL), 100 °C, 36 h. Isolated yields are
reported on the basis of phenol.
Support of this work by the “973” Project from the MOST of
China (2015CB856600, 2013CB228102) and NSFC (No.
21332001) is gratefully acknowledged. We also thank Pei-Ling
Xu (Peking University) for his help with HPLC analysis.
C
DOI: 10.1021/acs.orglett.6b02656
Org. Lett. XXXX, XXX, XXX−XXX

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Chem. Soc. 2014, 136, 14951. (i) Harris, M. R.; Konev, M. O.; Jarvo, E.
R. J. Am. Chem. Soc. 2014, 136, 7825. (j) Kondo, H.; Akiba, N.; Kochi,
T.; Kakiuchi, F. Angew. Chem., Int. Ed. 2015, 54, 9293. (k) Ogiwara, Y.;
Kochi, T.; Kakiuchi, F. Org. Lett. 2011, 13, 3254. (l) Cong, X.; Tang,
H.; Zeng, X. J. Am. Chem. Soc. 2015, 137, 14367. (m) Sergeev, A. G.;
Hartwig, J. F. Science 2011, 332, 439. (n) Dankwardt, J. W. Angew.
Chem., Int. Ed. 2004, 43, 2428. (o) Wenkert, E.; Michelotti, E. L.;
Swindell, C. S. J. Am. Chem. Soc. 1979, 101, 2246. (p) Zarate, C.;
Manzano, R.; Martin, R. J. Am. Chem. Soc. 2015, 137, 6754.
(q) Alvarez-Bercedo, P.; Martin, R. J. Am. Chem. Soc. 2010, 132,
17352. (r) Leiendecker, M.; Hsiao, C. C.; Guo, L.; Alandini, N.;
Rueping, M. Angew. Chem., Int. Ed. 2014, 53, 12912. (s) Guan, B.-T.;
Xiang, S.-K.; Wu, T.; Sun, Z.-P.; Wang, B.-Q.; Zhao, K.-Q.; Shi, Z.-J.
Chem. Commun. 2008, 1437.
(8) (a) Yu, D.-G.; Li, B.-J.; Zheng, S.-F.; Guan, B.-T.; Wang, B.-Q.;
Shi, Z.-J. Angew. Chem., Int. Ed. 2010, 49, 4566. (b) Yu, D.-G.; Shi, Z.-J.
Angew. Chem., Int. Ed. 2011, 50, 7097. (c) Yu, D.-G.; Wang, X.; Zhu,
R.-Y.; Luo, S.; Zhang, X.-B.; Wang, B.-Q.; Wang, L.; Shi, Z.-J. J. Am.
Chem. Soc. 2012, 134, 14638. (d) Cao, Z.-C.; Luo, F.-X.; Shi, W.-J.;
Shi, Z.-J. Org. Chem. Front. 2015, 2, 1505. (e) Cao, Z.-C.; Yu, D.-G.;
Zhu, R.-Y.; Wei, J.-B.; Shi, Z.-J. Chem. Commun. 2015, 51, 2683.
(f) Ohgi, A.; Nakao, Y. Chem. Lett. 2016, 45, 45.
(9) (a) Knappke, C. E. I.; Grupe, S.; Gartner, D.; Corpet, M.;
Gosmini, C.; Jacobi von Wangelin, A. Chem. - Eur. J. 2014, 20, 6828.
(b) Everson, D. A.; Weix, D. J. J. Org. Chem. 2014, 79, 4793.
(c) Everson, D. A.; Shrestha, R.; Weix, D. J. J. Am. Chem. Soc. 2010,
132, 920. (d) Czaplik, W. M.; Mayer, M.; Jacobi von Wangelin, A.
Angew. Chem., Int. Ed. 2009, 48, 607. (e) Qian, X.; Auffrant, A.;
Felouat, A.; Gosmini, C. Angew. Chem., Int. Ed. 2011, 50, 10402.
(f) Gu, J.; Wang, X.; Xue, W.; Gong, H. Org. Chem. Front. 2015, 2,
1411. (g) Xu, H.; Zhao, C.; Qian, Q.; Deng, W.; Gong, H. Chem. Sci.
2013, 4, 4022. (h) Krasovskiy, A.; Duplais, C.; Lipshutz, B. H. J. Am.
Chem. Soc. 2009, 131, 15592. (i) Liu, J. H.; Yang, C. T.; Lu, X. Y.;
Zhang, Z. Q.; Xu, L.; Cui, M.; Lu, X.; Xiao, B.; Fu, Y.; Liu, L. Chem. -
Eur. J. 2014, 20, 15334. (j) Bhonde, V. R.; O’Neill, B. T.; Buchwald, S.
L. Angew. Chem., Int. Ed. 2016, 55, 1849. (k) Moragas, T.; Correa, A.;
Martin, R. Chem. - Eur. J. 2014, 20, 8242. (l) Ackerman, L. K. G.;
Lovell, M. M.; Weix, D. J. Nature 2015, 524, 454. (m) Qian, Q.; Zang,
Z.; Wang, S.; Chen, Y.; Gong, H.; Lin, K. Synlett 2013, 24, 619.
(n) Ilies, L.; Kobayashi, M.; Matsumoto, A.; Yoshikai, N.; Nakamura,
E. Adv. Synth. Catal. 2012, 354, 593.
REFERENCES
■
(1) (a) Diederich, F.; Stang, P. J. Metal-Catalyzed Cross-Coupling
Reactions; John Wiley & Sons, 2008. (b) Miyaura, N.; Buchwald, S. L.
Cross-Coupling Reactions: A Practical Guide; Topics in Current
Chemistry; Springer Science & Business Media, 2002; Vol. 219.
(c) Alimardanov, A.; Schmieder-van de Vondervoort, L.; de Vries, A.
H. M.; de Vries, J. G. Adv. Synth. Catal. 2004, 346, 1812. (d) Negishi,
E. Acc. Chem. Res. 1982, 15, 340. (e) Heck, R. F. Acc. Chem. Res. 1979,
12, 146. (f) Hiyama, T.; Shirakawa, E. Cross-Coupling Reactions;
Springer: 2002; p 61.
(2) (a) Cepanec, I. Synthesis of Biaryls; Elsevier, 2010. (b) Nicolaou,
K.; Bulger, P. G.; Sarlah, D. Angew. Chem., Int. Ed. 2005, 44, 4442.
(c) Hassan, J.; Sevignon, M.; Gozzi, C.; Schulz, E.; Lemaire, M. Chem.
Rev. 2002, 102, 1359. (d) Fanta, P. E. Synthesis 1974, 1974, 9.
(e) Ashenhurst, J. A. Chem. Soc. Rev. 2010, 39, 540. (f) Suzuki, A.
Angew. Chem., Int. Ed. 2011, 50, 6722.
(3) (a) Johansson Seechurn, C. C.; Kitching, M. O.; Colacot, T. J.;
Snieckus, V. Angew. Chem., Int. Ed. 2012, 51, 5062. (b) Old, D. W.;
Wolfe, J. P.; Buchwald, S. L. J. Am. Chem. Soc. 1998, 120, 9722.
(c) Littke, A. F.; Fu, G. C. Angew. Chem., Int. Ed. 1998, 37, 3387.
(d) Cristofoli, W. A.; Keay, B. A. Tetrahedron Lett. 1991, 32, 5881.
(e) Cherney, A. H.; Kadunce, N. T.; Reisman, S. E. Chem. Rev. 2015,
115, 9587.
(4) (a) Rosen, B. M.; Quasdorf, K. W.; Wilson, D. A.; Zhang, N.;
Resmerita, A.-M.; Garg, N. K.; Percec, V. Chem. Rev. 2011, 111, 1346.
(b) Tobisu, M.; Chatani, N. Acc. Chem. Res. 2015, 48, 1717.
(c) Cornella, J.; Zarate, C.; Martin, R. Chem. Soc. Rev. 2014, 43, 8081.
(d) Yu, D.-G.; Li, B.-J.; Shi, Z.-J. Acc. Chem. Res. 2010, 43, 1486.
(e) Su, B.; Cao, Z.-C.; Shi, Z.-J. Acc. Chem. Res. 2015, 48, 886. (f) Li, B.
J.; Yu, D. G.; Sun, C. L.; Shi, Z. J. Chem. - Eur. J. 2011, 17, 1728.
(g) Tollefson, E. J.; Hanna, L. E.; Jarvo, E. R. Acc. Chem. Res. 2015, 48,
2344. (h) Tasker, S. Z.; Standley, E. A.; Jamison, T. F. Nature 2014,
509, 299. (i) Shi, Z.-J. Homogeneous Catalysis for Unreactive Bond
Activation; John Wiley & Sons, 2014.
(5) (a) Mesganaw, T.; Fine Nathel, N. F.; Garg, N. K. Org. Lett.
2012, 14, 2918. (b) Mesganaw, T.; Silberstein, A. L.; Ramgren, S. D.;
Nathel, N. F. F.; Hong, X.; Liu, P.; Garg, N. K. Chem. Sci. 2011, 2,
1766. (c) Meng, L.; Kamada, Y.; Muto, K.; Yamaguchi, J.; Itami, K.
Angew. Chem., Int. Ed. 2013, 52, 10048. (d) Harris, M. R.; Hanna, L.
E.; Greene, M. A.; Moore, C. E.; Jarvo, E. R. J. Am. Chem. Soc. 2013,
135, 3303. (e) Huang, K.; Yu, D.-G.; Zheng, S.-F.; Wu, Z.-H.; Shi, Z.-J.
Chem. - Eur. J. 2011, 17, 786. (f) Guan, B.-T.; Lu, X.-Y.; Zheng, Y.; Yu,
D.-G.; Wu, T.; Li, K.-L.; Li, B.-J.; Shi, Z.-J. Org. Lett. 2010, 12, 396.
(6) (a) Li, B.-J.; Xu, L.; Wu, Z.-H.; Guan, B.-T.; Sun, C.-L.; Wang, B.-
Q.; Shi, Z.-J. J. Am. Chem. Soc. 2009, 131, 14656. (b) Li, B.-J.; Li, Y.-Z.;
Lu, X.-Y.; Liu, J.; Guan, B.-T.; Shi, Z.-J. Angew. Chem., Int. Ed. 2008,
47, 10124. (c) Guan, B.-T.; Xiang, S.-K.; Wang, B.-Q.; Sun, Z.-P.;
Wang, Y.; Zhao, K.-Q.; Shi, Z.-J. J. Am. Chem. Soc. 2008, 130, 3268.
(d) Zarate, C.; Martin, R. J. Am. Chem. Soc. 2014, 136, 2236.
(10) Xie, L.-G.; Wang, Z.-X. Chem. - Eur. J. 2011, 17, 4972.
(11) Luo, Y.-R. Handbook of Bond Dissociation Energies in Organic
Compounds; CRC Press, 2002.
́
(e) Cornella, J.; Gomez-Bengoa, E.; Martin, R. J. Am. Chem. Soc. 2013,
135, 1997. (f) Takise, R.; Muto, K.; Yamaguchi, J.; Itami, K. Angew.
Chem., Int. Ed. 2014, 53, 6791. (g) Koch, E.; Takise, R.; Studer, A.;
Yamaguchi, J.; Itami, K. Chem. Commun. 2015, 51, 855. (h) Muto, K.;
Yamaguchi, J.; Itami, K. J. Am. Chem. Soc. 2012, 134, 169. (i) Quasdorf,
K. W.; Tian, X.; Garg, N. K. J. Am. Chem. Soc. 2008, 130, 14422.
(j) Correa, A.; Martin, R. J. Am. Chem. Soc. 2014, 136, 7253.
́
(k) Correa, A.; Leon, T.; Martin, R. J. Am. Chem. Soc. 2014, 136, 1062.
(l) Kinuta, H.; Hasegawa, J.; Tobisu, M.; Chatani, N. Chem. Lett. 2015,
44, 366.
(7) (a) Tobisu, M.; Takahira, T.; Ohtsuki, A.; Chatani, N. Org. Lett.
2015, 17, 680. (b) Tobisu, M.; Takahira, T.; Chatani, N. Org. Lett.
2015, 17, 4352. (c) Tobisu, M.; Morioka, T.; Ohtsuki, A.; Chatani, N.
Chem. Sci. 2015, 6, 3410. (d) Kinuta, H.; Tobisu, M.; Chatani, N. J.
Am. Chem. Soc. 2015, 137, 1593. (e) Tobisu, M.; Shimasaki, T.;
Chatani, N. Angew. Chem., Int. Ed. 2008, 47, 4866. (f) Tollefson, E. J.;
Erickson, L. W.; Jarvo, E. R. J. Am. Chem. Soc. 2015, 137, 9760.
(g) Yonova, I. M.; Johnson, A. G.; Osborne, C. A.; Moore, C. E.;
Morrissette, N. S.; Jarvo, E. R. Angew. Chem., Int. Ed. 2014, 53, 2422.
(h) Tollefson, E. J.; Dawson, D. D.; Osborne, C. A.; Jarvo, E. R. J. Am.
D
DOI: 10.1021/acs.orglett.6b02656
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