Substituent changes in the salen ligands of CuIINaI-complexes to induce various structures and catalytic activities towards 2-imidazolines from nitriles and 1,2-diaminopropane

Article abstract of DOI:10.1039/c9cc00879a

Based on various comparable salen ligands, three synthesized Cu^IINa^I-complexes present efficient catalytic activities for the coupling and cyclization reaction of 1,2-diaminopropane with nitriles towards 2-imidazolines. The catalytic results show that salen ligands with an electron-donating substituent and small steric hindrance improve the catalytic activity.

Full text of DOI:10.1039/c9cc00879a

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DOI: 10.1039/C9CC00879A
Journal Name
COMMUNICATION
II
I
Substituent changes in salen of Cu Na -complexes to induce the
various structures and catalytic activities towards 2-imidazolines
from nitriles and 1,2-diaminopropane†
Received 00th January 20xx,
Accepted 00th January 20xx
a
a
b
c
a
a
Quan-Quan Li,‡ Peng-Xiu He,‡ Jin Zhang, Ji-Dong Zhang, Yu-Meng Xin, Ping Liu,* Yao-Yu
a
a
DOI: 10.1039/x0xx00000x
Wang and Jian-Li Li*
www.rsc.org/
Based on various comparable salen ligands, three synthesized have been devoted to expand the products 2-imidazolines, develop
II
I
Cu Na -complexes present efficient catalytic activities for the new catalysts, and explore their structure-activity relationships to
coupling and cyclization reaction of 1,2-diaminopropane with enable rational catalyst design.
nitriles towards 2-imidazolines. Their catalytic results show that Complexes as catalysts showed better performances in some organic
the salen ligands with electron-donating substituent and small syntheses, for they contain catalytical active sites at either metal
3
II
II
steric hindrance improve the catalytic activity.
nodes or ligands. Our group researched three Cu complexes, Cu -
2
g
IAA (IAA = indole-3-acetate), [(CuL0.5
-Imidazolines, as a class of bioactive molecules, have been found in 2,2’-bipyridine-3,3’,6,6’-tetracarboxylic acid) , can initiate the
H O)·H
2
2
2
O]
n n
and [CuL0.5] (L =
h
2
many applications, such as pharmaceutical chemistry, synthetic reactions of ED and aryl nitriles, and found that the metal
1
,2
organic chemistry, and coordination chemistry. Commensurate coordination environments can affect the catalytic activation
with their importance, numerous methods have been developed for temperatures. But further studies on the structure/activity
1
b
their preparation. Among them, a simple and efficient route is the relationships remain absent. Salen, as excellent directional and high
4
coupling and cyclization of diamines and nitriles. But up to now, complexational ligands, can be candidate to furnish complexes. And
related reported works had its limitations of substrates and more importantly, it has been found that some metallosalen
2
catalysts. In this method, the precursors commonly are aryl nitriles complexes can catalyze a number of chemical reactions, including
2
4a
4b
4c
4d
and ethylenediamine (ED), but other diamines such as 1,2- oxidation, cyclization, cycloaddition, polymerization , etc. In
diaminopropane (DAP) are seldom reported.2
a,2b
For some 2- contrast, the synthesis of 2-imidazolines initiated by salen complexes
imidazolines from DAP, it is interesting that there are reported two is still an unexplored area. Thus, we have chosen three comparable
ED
DAP
DAC
5
reasonable equivalent tautomeric forms for the same 2-imidazolines salen H
2
II
L , H
2
L
, and H
2
L
(Scheme 1), and synthesized three
2
c
I
compound, because the methyl substituent could reside on either new Cu Na -salen complexes to study their structural variations and
C4 or C5 of imidazolines ring (Scheme 1). Thus, it seems to be catalytic activities towards 2-imidazolines. Seventeen 2-imidazolines
amusing to determine which is the most stable form for the same 2- products have been prepared and twelve of them are first reported.
imidazolines compound. On the other hand, this reaction usually Notably, the locations of their methyl substituents are examined
2
d
2e
used small molecules as catalysts including S, ZrOCl
sulphuric acid,
2
·H
2
O, Silica through
density
functional
theory
(DFT)
calculation.
2
f
2a
Silica supported tungstosilicic acid,
p-
2
b
Toluenesulfonic acid, etc. Accordingly, further tremendous efforts Scheme 1. Schematic representation of 2-imidazolines in which the
methyl located at C4 or C5 of imidazolines ring, and the previous
5
reported salen ligands used in the present work.
a. Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the
Ministry of Education, Shaanxi Key Laboratory of Physico-Inorganic Chemistry,
College of Chemistry and Materials Science, Northwest University, Xi'an 710127,
P. R. China. E-mail: liuping@nwu.edu.cn; lijianli@nwu.edu.cn.
b.
College of Chemistry & Chemical Engineering, Shaanxi University of Science &
Technology, Xi'an 710021, P. R. China.
Department of Chemistry and Chemical Engineering, Ankang University, Ankang
c.
Shaanxi, 725000, P. R. China.
†Electronic Supplementary Information (ESI) available: Experimental details,
crystallographic data, magnetic details, UV-vis spectra and MS data, catalytic
reaction and DFT calculation details. CCDC for 1 , 2 and 3 : 1875301-1875303.
For ESI and crystallographic data in CIF or other electronic format see DOI:
ED
LDAP and H
refluxing
(OAc)(H
LDAC separately react with Cu(OAc)
ED
DAP
DAC
The H
NaN
Cu Na
L , H
·H
one
O and
3D
2
2
2
2
2
3
in
MeOH,
affording
1
‡
0.1039/x0xx00000x
These authors contributed equally.
ED
ED
[
4
2
(L )
2
(N
3
)
5
2
O)]
n
(1 ), two isostructural heptanuclear
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J. Name., 2013, 00, 1-3 | 1
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Journal Name
(LDAP)
(N
(N
)
(OAc)
(OAc)
(OMe)
(OMe)
(H
O)
]·H
(2DAP
)
and Cu -azide systems, they exhibited various ferromagnetic behaviours
II
[
Cu
Cu
5
Na
Na
2
2
3
6
2
2
2
DAC
2
2
O
View Article Online
DOI: 10.1039/C9CC00879A
(LDAC)
5
2
2
3
)
6
2
2
(3 ). The X-ray single crystal (Fig. S9-S11).
structural determination reveals that all of them have two parts: To evaluate the catalytic behaviours of 1 -3
Cu Na -salen and Cu -azide building units. But interestingly, their imidazolines, the reaction of 2-pyridyl nitrile (1a) and DAP (2) was
components and arrangements are different (Fig. 1 and S4). For 1 , performed, and catalysts screening result shows that 1 -3
it crystallizes in the orthorhombic space group Pbca. In the effective catalysts (Table S4). Considering that 2
unit, there are four penta- isostructure, 1 and 3 were used to identify the optimal reaction
coordinated Cu atoms (τ = 0.16 for Cu3 and 0.30 for Cu4) held conditions. The solvents, temperatures, reaction time and amounts
ED DAC
towards 2-
II
I
II
ED
ED DAC
are
DAP
and 3DAC are
II
ED
DAC
centrosymmetric Cu -azide Cu
4
6
together to form Cu
each Cu -azide links adjacent four Cu
1,1,3-azide, while azide (µ -) and acetate ion (µ
ornaments and suspend the two ends of Cu -azide unit. In each choose the following condition to continue our study: 0.05 mmol
Cu Na -salen, the tetra-coordinated Cu is embedded in N pocket catalyst, MeOH, 70 °C, and 10 h. By the different coordination
4
-azide by four µ1,1-azide and two µ1,1,3-azide, and of catalysts on the yield of product were further investigated, and
4
2
Na -salen through the µ1,3- and fortunately, the experimental results showed that the optimal
2
1
1
ED
DAC
µ
1
1
-η :η ) act as reaction conditions of 1 and 3 are similar (Table S5). Thus, we
4
II
I
2 2
O
2
h
II
I
II
with normal Cu-O and Cu-N bonds. And the two adjacent Cu Na - numbers of Cu2 in Cu -azide units (six-coordinated saturated Cu in
salen units are hold together into Cu
coordinated Na1 and hepta-coordinated Na2) which are linked by µ
2 4
H O and O atom of (L ) , and then connect adjacent two Cu -azide in fact, under the optimization of conditions, it was found that the
units into 3D framework upon considering Cu
azide as two and four connected nodes, respectively (Fig. S5). S5), showing better catalytic activity of 2 than that of 3 . This
However, a very interesting structural change is observed when fact suggests that the different catalytic efficiency of 2 and 3
ligand H
crystallize in the triclinic space group P-1. Different from Cu-azide on the Cu Na -salen parts, the different yields can presumably be
unit in 1 , in 2 and 3 , there are just three Cu atoms stacked via explained by the methyl and cyclohexyl substituents on salen
four µ1,1-azide to form Cu
acetate ion further coordinate with Cu and Na atoms of two Cu Na - donating, but catalyst 2
salen units, respectively. But unlike that in 1 , the Cu Na -salen just substituent on salen L with the smaller steric hindrance than the
acts as ornaments and suspends Cu
heptanuclear cooper(II) moleculer. This structural arrangement catalytic efficiencies of 2 and 3 seem to mainly result from the
showed that the steric effects of methyl/cyclohexyl groups may different steric demands of Cu Na -salen rather than the different
DAP
DAC
2
Na
2
-salen through Na (hexa-
2
vs. pentacoordinated unsaturated one in 3 ), it is an initial
impression that 3 would had higher activity than that of 2DAP. But
DAC
2
-
ED 2-
DAP
ED
DAC
2
Na
2
-salen and Cu
4
-
yields follow the order: 2 (91%)＞1 (85%)＞3 (78%) (Table
DAP
DAC
DAP
DAC
ED
DAP
DAC
DAP DAC
II
2
L
is exchanged by H
2
L
or H
2
L
. For 2 /3 , they seems to not result from the various Cu -azide. Then when we focus
II
I
ED
DAP
DAC
4
d,7
3
-azide unit, then the azide (µ1,1-) and ligand.
Both methyl and cyclohexyl substituents are electron-
II
I
DAP
with the higher yield possesses methyl
ED
II
I
DAP
DAC
DAC
3
-azide unit to extend into cyclohexyl substituents on L
of 3 . Therefore the different
DAP
DAC
II
I
II
I
II
prevent the staking of two Cu Na -Salen and change the structural coordination numbers of Cu2 on Cu -azide units. Based on above
pattern of Cu -azide systems, further resulting in different structural discussion, it seems reasonable that the different catalytic activities
units and dimensionality. Moreover, there are some differences between 1 and 2 /3
between 2 and 3 : in Cu
while penta-coordianted in 3 , and the acetate ions show different salen of Cu Na -salen units. Compared to 2 , the catalytic activity
coordination modes (μ
II
ED
DAP DAC
may be also from the influence of the
DAP
DAC
DAP
3
-azide, Cu2 is hexa- coordinated in 2
electronic and steric hindrance effects of the diverse substituent
DAC
II
I
DAP
1
2
DAP
ED
2
-η :η in 2 vs.
of 1 decreased a little bit perhaps due to the absence of electron-
donating substituent of salen L . But for 3 , the biggest steric
effect of substituent on L
ED
DAC
DAC
seems to prevail over the electron-
donating effect leading to lowest yield. Therefore, the electron-
II
I
donating and steric hindrance substituent of Cu Na -salen units will
affect the catalytic activity.
Based on above results, a substrate scope of aryl nitriles (1b-1q) was
DAP
examined under the optimized conditions using catalyst 2 . And
the results show it is active for seventeen 2-imidazolines products,
among which twelve are new. All obtained 2-imidazolines derivatives
8
are characterized by NMR, IR, and HRMS. For five- or six-membered
hetercyclic aromatic nitriles, the yield is high (Table 1, entry 1-5).
Compared to benzonitrile (1f), the electron-withdrawing groups (-F,
-
Cl, -Br, -CF
yield (Table 1, entry 7-11), whereas the electron-donating group
Fig. 1 The metal coordination environments of 1 (a), 2DAP (b) and (methyl-, azyl- and methoxy-) decrease the yield (Table 1, entry 12-
3
, -CN) at the para-position of aromatic ring give higher
ED
DAC
ED
DAP
3
(c). The symmetry codes: for 1 , A = -x+2, -y+2, -z+1; for 2 , A 14). This suggests that the enhanced electrophilic nature of nitrile
DAC
=
-x+1,-y+3, -z; for 3 , A = -x, -y+1, -z.
carbon is achieved in the existence of electron-withdrawing groups
at para-position of aromatic ring, thereby leading to a higher
0
2
DAC
II
I
μ
2
-η :η in 3 ); in Cu Na -Salen, except for the diverse diamine activation of the substrate. Similarly, the electron-withdrawing
) at the meta-position of aromatic ring affords high yield
vs. hexa-coordinated in 3 ). Their (93%), while the yield is significantly reduced for the electron-
magnetic measurements were performed, and due to the different donating group (-OMe) (Table 1, entry 15 and 16). And notably, both
backbones, the coordination environments around Na are different group (-CF
3
DAP
DAC
(
hepta-coordinated in 2
2
| J. Name., 2012, 00, 1-3
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ED
+
-
3
CF and -OMe groups at meta-positions give higher yield than they presence of [L CuNa] ([M+H] m/z: 413.9, Found, 414.0) and
View Article Online
DOI: 10.1039/C9CC0087 9E DA
ED
+
2 2 2 2
respective at para-positions. Further, the effects of two electron- [(L ) Cu Na (H O)] ([M+H] m/z: 844.7, Found: 844.1) in 1 ,
withdrawing halogen groups at different positions of aromatic ring [L CuNa] ([M+H]+ m/z: 427.9, Found: 428.0) and
DAP
are also studied. Locating at 3 and 5 positions give higher yield (up to [LDAPCu
9
Na(OCH
O)(CH
COO)(N
] ([M+H] m/z: 873.1, Found:
+
3
3
)(H
2
DAC
3
3
)
5
+
DAP
5%) (Table 1, entry 17), while at 3 and 4 positions reduce the yield 873.2) in 2 , and [L CuNa] ([M+H] m/z: 468.0, Found: 468.1) and
DAC
+
(Table 1, entry 18-19).
[L Cu
3
Na(OCH
3
)(CH
3
COO)(N
3
)
5
] ([M+H] m/z: 913.2, Found: 913.2)
DAC
in 3 in the solution (Fig. S14). Furthermore, we have compared the
catalytic activities of 1 -3 , salen ligands (H
DAP a
ED DAC
ED
DAC
Table 1. Syntheses of 2-imidazolines catalyzed by 2
.
2
L -H
2
L
), Cu(II)
H2N
DAP
N
2
(0.05mmol)
(Cu(OAc) , CuSO and CuCl ) and NaN under the same experimental
Ar CN +
Ar
2
4
2
3
MeOH, 70 °C, 10h
H2N
N
H
3
conditions (Table S4). The Cu(OAc)
display a much lower catalytic activity (33-46%) than 1 -3 , and no
reaction occurs when adding salen ligands or NaN
for a longer reaction time (24 h), certifying that alone Cu(II) salts,
NaN or salen ligands only have poor or no catalytic activities.
Therefore, it seems that the reactions of aryl nitriles and DAP are
catalyzed by complexes 1 -3
Moreover, these products have two equivalent tautomeric forms 3
and 3’ (the methyl substituent resides on C5 and C4 of imidazolines
ring, respectively). To determine their most stable forms, the DFT
calculations were employed to calculate electronic and thermal free
2
, CuSO
4
and CuCl
2
were found to
ED DAC
1
2
Entr
y
Yields(%)
Nitriles
Products
b
3
even at stirring
N
CN
1
2
3
4
N
N
H
91
83
97
75
N
1a
1b
3a
3b
3c
3d
N
3
CN
N
N
N
H
N
ED DAC
N
CN
N
.
1
c
N
H
N
N
N
N
N
CN
N
H
1d
N
CN
S
5
N
H
96
S
1e
3e
3f
8
N
energies in implicit solvent mediums (methanol) of 3 and 3’. And the
CN
6
7
8
9
N
H
31
89
1
f
results indicate that besides 3j’ and 3o’-3r’, the rest compounds
having the C5-methyl substituents are more stable than that of the
C4-ones (Table S7). Besides, a plausible catalytic mechanism has
been raised in Scheme 2. The nitrile is activated by catalysts to afford
I), then DAP attacks (I) to give (II), lastly, cyclization of (II) provides
the final product by releasing NH
catalytic cycle.
N
F
Cl
Br
F
CN
1g
N
H
3g
3h
3i
N
Cl
CN
CN
1
h
i
N
H
81
97
N
(
Br
1
N
H
3
and the catalysts for the next
F
F
F
F
F
N
CN
CN
1
1
1
1
0
1
2
3
F
N
80
1j
H
3j’
3k
3l
N
NC
H3C
H2N
NC
1
k
N
91
H
Scheme 2. Proposed mechanism for preparing 2-imidazolines
catalyzed by catalysts.
N
CN
CN
H3C
H2N
1
1
l
N
H
27
N
m
N
H
trace
3m
3n
N
O
CN
CN
O
1
1
1
1
4
5
6
7
N
H
trace
93
1
n
N
F
F
F
N
H
F
F
1o
F
3o’
3p’
N
CN
N
H
50
O
O
1
p
Cl
Cl
N
CN
CN
CN
95
N
H
Cl
1q
1r
Cl
3q’
N
F
F
1
1
8
9
N
H
42
69
F
F
3
r’
N
F
F
N
H
Cl
1s
Cl
3s
a
Reaction conditions: various nitriles (2.0 mmol, 1.0 eq.), 1,2-
II
I
In conclusion, three Cu Na -complexes constructed by azide and
three comparable salen ligands were synthesized and characterized.
DAP
diaminopropane (4 mmol, 2 eq.), 2 (0.05 mmol, 0.025 eq.), MeOH
b
(8 mL), 70 °C for 10h, then rt. HPLC yield.
II
I
II
They are all constituted by Cu Na -salen and Cu -azide units, but their
structures, magnetic and catalytic activities have been changed to
some extent by altering the substituent on salen ligands. With the
different components and arrangements of Cu Na -salen and Cu -
azide units, there are structural varieties: 1 presents a 3D
In order to get more insight structural information of 1 -3DAC in the
methanol solution, the UV-vis spectral and MS data have been
characterized (Fig. S12-S14). Their UV-vis spectra in solid state show
that the adsorption band observed in the range of 680-720 nm
corresponds to d-d transition and strong bands at 240-551 nm are
due to the phenoxo-Cu(II) ligand to metal charge transition (LMCT).
The UV-vis spectra in methanol solution are similar to that in solid
state (Table S6), so it may be assumed that solution and solid-state
structures of complexes are similar. The MS analysis revealed the
ED
II
I
II
ED
DAP
DAC
framework, while 2 and 3 are isostructural heptanuclear. And
II
due to their different Cu -azide units, magnetic measurement results
ED DAC
also exhibit various ferromagnetic behaviours in 1 -3
.
Furthermore, the catalytic results demonstrate that though they are
efficient catalysts in the synthesis of 2-imidazolines products, their
catalytic efficiency diversities may be mainly due to the different
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Journal Name
II
I
Cu Na -salen units (diverse electronic and steric factors of substitutes 4. (a) C. X. Tan, J. J. Jiao, Z. J. Li, Y. Liu, X. Han and Y. Cui, Angew. Chem.
View Article Online
DOI: 10.1039/C9CC00879A
DAP
of salen). The metallosalen complex 2 with small sterical hindered
Int. Ed., 2018, 57, 2085-2090; (b) Q. C. Xia, Y. Liu, Z. J. Li, W. Gong
electron-donating substituent can efficiently improve the catalytic
performance. Besides, seventeen products (including twelve first
reported compounds 3a-3e, 3j’-3k and 3o’-3s) have been prepared,
and the most stable forms of these compounds were investigated by
performing DFT calculation. To our best knowledge, it is the first
report in the synthesis of 2-imidazolines catalyzed by metallosalen
complexes.
and Y. Cui, Chem. Commun., 2016, 52, 13167-13170; (c) T. T. Liu,
J. Liang, Y. B. Huang and R. Cao, Chem. Commun., 2016, 52,
13288-13291; (d) W. K. Gu, P. F.Xu, Y. R. Wang, Y. M. Yao, D. Yuan
and Q. Shi, Organometallics, 2015, 34, 2907-2916; (e) D. P. Chen,
R. Luo, M. Y. Wen, Y. Li, C. Chen and N. Zhang, Chem. Commun.,
2017, 53, 10930; (e) Y. L. Hou, R. W. Y. Sun, X. P. Zhou, J. H. Wang
and D. Li, Chem. Commun., 2014, 50, 2295.
This work was supported by the NSF of China (No. 21673173, 5. (a) A. Finelli, N. Hérault, A. Crochet and K. M. Fromm, Cryst. Growth
2
1572177, 21371142, and 21531007), the NSF of Shaanxi Province of
Des., 2018, 18, 1215-1226; (b) S. Majumder, S. Pasayat, A. K.
Panda, S. P. Dash, S. Roy, A. Biswas, M. E. Varma, B. N. Joshi, E.
Garribba, C. Kausar, S. K. Patra, W. Kaminsky, A. Crochet and R.
Dinda, Inorg. Chem., 2017, 56, 11190-11210; (c) J. W. Yang, Y. M.
Tian, J. Tao, P. Chen, H. F. Li, Y. Q. Zhang, P. F. Yan and W. B. Sun,
Inorg. Chem., 2018, 57, 8065-8077.
China (No. 2016JZ004 and 2015JZ003), the Xi'an City Science and
Technology Project (No. 2017085CG/RC048(XBDX004)), the Chinese
National Innovation Experiment Program for University Students
(G201710697034 and G201710697041) and the “Top-rated
Discipline” construction scheme of Shaanxi higher education for
financial support.
6. A. W. Addison and T. N. Rao, J. Chem. Soc. Dalton. Trans., 1984,
1
349-1356.
. (a) S. Rayati, A. Ghaemib and N. Sadeghzadeh, Catal. Commun.,
010, 11, 792-796; (b) K. S. Banu, T. Chattopadhyay, A. Banerjee,
S. Bhattacharya, E. Zangrando, and D. Das, J. Mol. Catal. A-Chem.,
009, 310, 34-41; (c) N. J. V. Zee, M. J. Sanford and G. W. Coates,
J. Am. Chem. Soc., 2016, 138, 2755-2761.
7
Conflicts of interest
There are no conflicts to declare.
2
2
Notes and references
8. See the ESI†.
1
. (a) T. Arai, H. Ogawa, A. Awata, M. Sato, M. Watabe and M.
Yamanaka, Angew. Chem. Int. Ed., 2015, 54, 1595-1599; (b) H. Liu
and D. M. Du, Adv. Synth. Catal., 2009, 351, 489-519; (c) S. J.
Huang, Y. L. Shao, L. X. Zhang and X. G. Zhou, Angew. Chem. Int.
Ed., 2015, 54, 14452-14456; (d) A. Franchino, J. Chapman, I.
Funes-Ardoiz, R. S. Paton and D. J. Dixon, Eur. Chem. J., 2018, 24,
1
7660-17664.
2
. (a) M. Nasr-Esfahani, M. Montazerozohori, M. Moghadam and P.
Akhlaghi, ARKIVOC, 2010, 2, 97-109; (b) M. Nasr-Esfahani, M.
Montazerozohori and S. Mehrizi, J. Heterocyclic Chem., 2011, 48,
2
49; (c) J. E. Lönnqvist, T. Holmström and L. F. Jalander, J. Chem.
Res., 2002, 1, 7-7; (d) V. Mirkhani, M. Moghadam, S.
Tangestaninejada and H. Kargara, Tetrahedron Lett., 2006, 47,
2
129-2132; (e) V. Mirkhani, I. Mohammadpoor-Baltork, M.
Moghadam, S. Tangestaninejad, M. Abdollahi-Alibeik and H.
Kargar, Appl. Catal., A, 2007, 325, 99-104; (f) I. Mahammadpoor-
Baltork, V. Mirkhani, M. Moghadam, S. Tangestaninejad, M. A.
Zolfigol, M. Abdollahi-Alibeik, A. R. Khosropour, H. Kargar and S.
F. Hojati, Catal. Commun., 2008, 9, 894; (g) J. Zhang, X. Wang, M.
P. Yang, K. R. Wan, B. Yin, Y. X. Wang, J. L. Li and Z. Shi,
Tetrahedron Lett., 2011, 52, 1578-1582; (h) Q. Q. Li, C. Y. Ren, Y.
Y. Huang, J. L. Li, P. Liu, B. Liu, Y. Liu and Y. Y. Wang, Chem. Eur. J.,
2
015, 21, 4703-4711.
. (a) C. M. Kozak, K. Ambrose and T. S. Anderson, Coord. Chem. Rev.,
018, 376, 565-587; (b) N. Kuwamura, Y. Kurioka, N. Yoshinari
3
2
and T. Konno, Chem. Commun., 2018, 54, 10766-10769; (c) X.
Jiang, B. Yang, Q. Q. Yang, C. H. Tung and L. Z. Wu, Chem.
Commun., 2018, 54, 4794; (d) H. Shigehisa, M. Hayashi, H.
Ohkawa, T. Suzuki, H. Okayasu, M. Mukai, A. Yamazaki, R. Kawai,
H. Kikuchi, Y. Satoh, A. Fukuyama and K. Hiroya, J. Am. Chem. Soc.,
2
016, 138, 10597-10604.
4
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