An asymmetric hydrocyanation/Michael reaction of α-diazoacetates: Via Cu(i)/chiral guanidine catalysis

Article abstract of DOI:10.1039/c9cc09521g

An asymmetric one-pot hydrocyanation/Michael reaction of α-aryl diazoacetates with trimethylsilyl cyanide, tert-butanol, and N-phenylmaleimides has been realized. Using a chiral guanidinium salt/CuBr catalyst, a series of cyanide-containing pyrrolidine-2,5-diones could be obtained in good yields with excellent diastereo- and enantioselectivities.

Full text of DOI:10.1039/c9cc09521g

View Article Online
View Journal
ChemComm
Chemical Communications
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: S. Ruan, X. Zhong,
Q. Chen, X. Feng and X. Liu, Chem. Commun., 2020, DOI: 10.1039/C9CC09521G.
Volume 54
Number
January 2018
Pages 1-112
This is an Accepted Manuscript, which has been through the
Royal Society of Chemistry peer review process and has been
accepted for publication.
1
4
ChemComm
Chemical Communications
rsc.li/chemcomm
Accepted Manuscripts are published online shortly after acceptance,
before technical editing, formatting and proof reading. Using this free
service, authors can make their results available to the community, in
citable form, before we publish the edited article. We will replace this
Accepted Manuscript with the edited and formatted Advance Article as
soon as it is available.
You can find more information about Accepted Manuscripts in the
Information for Authors.
Please note that technical editing may introduce minor changes to the
text and/or graphics, which may alter content. The journal’s standard
Terms & Conditions and the Ethical guidelines still apply. In no event
shall the Royal Society of Chemistry be held responsible for any errors
or omissions in this Accepted Manuscript or any consequences arising
from the use of any information it contains.
ISSN 1359-7345
COMMUNICATION
S. J. Connon, M. O. Senge et al.
Conformational control of nonplanar free base porphyrins:
towards bifunctional catalysts of tunable basicity
rsc.li/chemcomm

Page 1 of 4
Please d oC hn eo mt Ca do mj u ms t margins
View Article Online
DOI: 10.1039/C9CC09521G
COMMUNICATION
Asymmetric hydrocyanation/Micheal reaction of α-
diazoacetates via Cu(I)/chiral guanidine catalysis
Sai Ruan, Xia Zhong, Quangang Chen, Xiaoming Feng, and Xiaohua Liu*
Received 00th January 20xx,
Accepted 00th January 20xx
DOI: 10.1039/x0xx00000x
An asymmetric one-pot hydrocyanation/Micheal reaction of α-
aryl diazoacetates with trimethylsilyl cyanide, tert-butanol, and N-
phenylmaleimides has been realized. Using a chiral guanidinium
salt/CuBr catalyst, a series of cyanide-containing pyrrolidine-2,5-
diones could be obtained in good yields with excellent diastereo-
and enantioselectivities.
a) Asymmetric MCR of -diazoesters via trapping protic onium ylides with electrophlies6e
α
(
O
Ar4
3-
C
η
3H5
)]
2
[
PdCl(
NH
N
2
1
3
Ar
Ar
Ar4
chiral phosphoric acid
Ar2
N
Ar3
1
Ar1
CO
R1
N
+
3
R O
2
C
2
then H O
Ar2
O
(b) Asymmetric MCR of -diazoesters, terminal alkynes and isatins7
α
R3
O
HO
R1
CuBr/YBr
chiral guanidinium salt
3
N
2
Multicomponent catalysis has attracted wide attention for the
advantages of simple operation, high atomic economy, more
compliance with green chemistry and environmentally friendly
O
O
R2
CO
2
R1
CO
R2
R3
N
N
2
PG
PG
1
α
(c) Asymmetric MCRs of -diazoesters, TMSCN, alcohol, and maleimides (this work)
requirements. Especially, the interest towards asymmetric
H
Ar
CO
CN
catalytic one-pot multicomponent reactions increased rapidly
O
CuBr
R1
N
2
2
2
+
"HCN"
+
chiral guanidinium salt
O
over the past decade. However, the identification of the chiral
R1
N
R2
Ar
CO
2
N
R2
O
catalysts is challenging due to the presence of multiple species
in the multicomponent processes. Enantioselective
organocatalysis and metal/organo or metal/metal relay-
(
TMSCN + ROH)
O
Scheme 1 Representative examples for asymmetric multi-component reactions
of -diazoacetates.
α
3
catalysis have contributed to this fast-growing subfield.
Diazo carbonyl compounds,4 which are considered as
valuable precursors to metal carbenes, have been widely
applied in the multicomponent relay reactions in recent years.
,9a-c
3
catalytic insertion reactions of α-diazoesters, such as CF
9d-j
9k
9l
9m
3
SCF ,
3
OCF , CN, and azide have been well established,
5
no related multicomponent reactions via trapping of the
intermediates were disclosed. The difficult might rise from the
instability of the metal species and the competing protonation
process. As part of our continuous research in asymmetric
There are several representative strategies for the
enantioselective multicomponent reaction of
α
-diazo carbonyl
compounds. For instance, Hu’s6 and other groups have
discovered novel multicomponent reactions via trapping of
ammonium/oxonium ylides with a variety of electrophiles, and
the asymmetric versions could be achieved with the assistance
a-f
6g-i
10
chiral guanidine catalysis and asymmetric reaction of α-diazo
7,10a-c
compounds,
we envisioned that the enantioselective
hydrocyanation/addition reaction of α-diazoester, “HCN” and
electrophiles would allow the readily access to the cyanide-
containing compounds with a quaternary carbon center
6e
of cooperative metal salt/chiral organocatalyst (Scheme 1a)
or chiral metal complexes.6
c,6h
Enantioselective trap of the
carbene species with terminal alkynes and isatins was realized
by our group through copper salt/chiral guanidinium salt
9l,11
(
Scheme 1c).
Herein, we report our endeavor in the
Cu(I)/chiral guanidinium salt promoted asymmetric one-pot
reaction of α-diazoesters with TMSCN, BuOH, and maleimides.
The current reaction presented a new multi-component
reaction involving a sequence of two reactions with different
reaction profiles.
catalysis to yield axially chiral tetrasubstituted allenoates
t
7
(
Scheme 1b). The CuI-catalyzed multicomponent reaction of
trifluorodiazoethanes, terminal alkynes and nitrosobenzenes
8
enabled the formation of dihydroisoxazoles. Although the
In our preliminary investigation, we selected methyl
diazoacetate 1a, TMSCN, methanol, and N-phenylmaleimide
as the model substrates to optimize the reaction conditions.
Primary study showed that in the catalytic amount of CuCl, the
hydrocyanation reaction of 1a, TMSCN, and alcohol was
sluggish, and it could be accelerated if higher amount of
α-aryl
Key Laboratory of Green Chemistry & Technology, Ministry of Education,
College of Chemistry, Sichuan University, Chengdu 610064, P. R. China.
E-mail: liuxh@scu.edu.cn.
2
a
†
Electronic Supplementary Information (ESI) available. CCDC 1901489. For ESI and
crystallographic data in CIF or other electronic format see DOI:10.1039/x0xx00000x
Please do not adjust margins

Please d oC hn eo mt Ca do mj u ms t margins
Page 2 of 4
COMMUNICATION
Journal Name
Table 1 Optimization of the reaction conditionsa
stereoselectivity, and the product was given in 65% yield, 95%
View Article Online
DOI: 10.1039/C9CC09521G
ee with 96:4 dr (entry 9). Further exploration of alcohols
O
O
N
2
Guanidine (10 mol%)
CuX (20-100 mol%)
t
showed that BuOH could be used to promote the reaction in
TMSCN
MeOH
N
Ph
Ph
N
Ph
CO
O
2
Me
CH Cl2
, 30
C
o
CN
Ph
80% yield with maintained enantioselectivity and
2
O
O
CO
2
Me
diastereoselectivity (entry 10). Finally, increasing the amount
1
a
2a
3aa
t
O
Ph
O
Ph
of
α
-diazoester, TMSCN, and BuOH to 1.2 equivalences
Ph
H
N
S
H
H
O
N
N
resulted in 86% yield, 96:4 dr with 95% ee (entry 11).
Having identified the optimized four-component reaction
N
N
Ts
N
Ts
n
Ar
N
H
Ph
O
N
H
Ph
N
H
Ph
N
N
N
Cy
conditions, we next investigated the scope of
diazoacetates . As depicted in Table 2, both the ester group
and the aryl substituent on the -diazoesters affected the
α-aryl
Cy
Cy
Cy NH
Cy NH
Cy NH
G-3
1
G-2
Cy = Cyclohexyl)
G-1: n = 1, Ar = 4-MeC
G-4: n = 0, Ar = 4-MeC
6
6
H
4
H
4
α
(
G-5: n = 0, Ar = 1-naphthyl
yield dramatically. It was found that with the steric hindrance
of the ester group increased, the yield decreased gradually
with the diastereoselectivity and enantioselectivity remained
I
Yield (%)b
drc
ee (%)c
Entry Cu (mol%)
Guanidine
1
2
3
4
5
6
7
CuCl (100)
CuCl (100)
CuCl (100)
CuCl (100)
CuCl (100)
CuBr (100)
CuBr (50)
CuBr (20)
CuBr (20)
CuBr (20)
CuBr (20)
G-1
G-2
G-3
G-4
G-5
21
18
13
40
46
60
71
85
65
80
86
94:6
>19:1
84:16
88:12
88:12
88:12
88:12
88:12
96:4
8/5
31/-
(3aa-3ca). If tert-butyl phenyldiazoacetate 1d was subjected
into the system, only trace amount of the product was
detected. The position and electronic nature of the substituents on
the phenyl group of methyl α-aryl diazoacetates have obvious
influence on both the yield and enantioselectivity. The
products 3ga and 3ia bearing 4-methyl and 4-fluoro
substituent were obtained with good diastereo- and
enantioselectivities in 93% and 95% ee, respectively. The
5/11
49/33
67/43
73/47
74/49
74/47
95/-
G-5
G-5•HBr
G-5•HBr
G-5•HBr
G-5•HBr
G-5•HBr
d
8
9
1
1
d,e
d-f
0
96:4
96:4
95/-
95/-
reactions of 3-methyl or 4-methoxyl substituted α-aryl
1g
diazoesters proceeded well after the addition of DABCO,
affording the related product 3fa in 87% yield with 89% ee,
and 3ha in 68% yield with 93% ee. When other halo-
a
Unless otherwise noted, all reactions were carried out with chiral guanidine (10
I
mol%), Cu (100 mol%), α-diazoester 1a (0.10 mmol), TMSCN (1.0 equiv) and
MeOH (1.0 equiv) in CH Cl
added at 30 °C and reacted at 30 °C for 12 h. Isolated yield. Determined by
HPLC analysis. 5 Å MS (20 mg) was added. 2a was added at –30 °C for 24 h.
BuOH instead of MeOH. g 1a (1.2 equiv), TMSCN (1.2 equiv), BuOH (1.2 equiv);
2
2
(0.5 mL) at 30 °C for 2 h, then 2a (1.0 equiv) was substituted
α
-phenyl diazoesters including 2-F, 4-Cl, 4-Br, and
-I substituted ones, as well as -2-naphthyl diazoester, were
used for the reaction, the good yields and enantioselectivities
3ea 3ma 3ja 3ia) could be achieved with higher loading of
b
c
4
α
d
e
f
t
t
(
,
,
-
and 2a (1.0 mmol) at –30 °C for 24 h.
CuBr and DABCO as the additives (see the ESI for details).
copper salt was added. Thus, a variety of chiral guanidine-
amides12 was examined in combination with equivalent CuCl in
Table 2 Substrate scope of α-aryl diazoacetates 1a
O
2
CH Cl
2
at 30 °C. To our delight, it was found that all of the
O
N
2
G-5 •HBr (10 mol%)
chiral guanidines could promote the reaction to give the
desired product 3aa (Table 1). However, the amino acid
backbone had obvious influence on the yield and
TMSCN
tBuOH
CuBr (20-50 mol%)
Ph
N
N
Ph
1
2
CN
Ar
Ar1
CO2
R
1
5 Å MS, CH
Cl
, 30 C, 2 h,
o
2
2
o
−
Then 30
C, 24 h
1
O
R1
O C
2
O
1a-1m
2
a
3aa-3ma
enantioselectivity of the reaction, and the
L-proline-based G-4
O
O
O
O
gave higher results (40% yield, 88:12 dr, and 49% ee) than the
guanidines G-1 to G-3 derived from ʟ-pipecolic acid,
Ph
N
O
Ph
N
Ph
N
O
CN
CO2
CN
Ph
N
CN
CO2Me
CN
R
1
CO
2
Me
F
CO2Me
O
O
tetrahydroisoquinoline acid, and
L-ramipril, respectively
(
entries 1-4). Based on our previous work, the guanidines
aac: R1
3ba: R1
= Me, 76% yield, 13:1 dr, 95% ee
3
10d,12c
= Et, 81% yield, 13:1 dr, 96% ee
ca: R1 = iPr, 68% yield, 13:1 dr, 96% ee
3eab
3fab
Me
embellished a sulfonamide unit
could be adjusted to
3ga
3
3
75% yield, 2:1 dr
85/70% ee
87% yield, 13:1 dr
89% ee
71% yield, 13:1 dr
95% ee
da: R
1
=
t
Bu, trace yield
change the reactivity and enantioselectivity. It was found that
the installation of 1-naphthyl group into G-5 enhanced the
enantioselectivity to 67% ee (entry 5). Fortunately, the
evaluation of the copper salts showed that the reactivity and
enantioselectivity increased (60% yield and 73% ee) when CuBr
was used instead of CuCl (entry 6). Encouraged by these
results, we conducted more detailed investigations. When the
guanidium salt G-5·HBr combined with CuBr was used as the
catalyst, the amount of CuBr could be decreased to 50 mol%
and the yield could be increased to 71% with maintained
enantioselectivity and diastereoselectivity (entry 7). Moreover,
the yield could be further improved in the presence of 20 mol%
O
O
O
O
N
Ph
N
Ph
N
CN
CO
Ph
N
CN
CN
CO
Ph
CN
2
Me
2Me
CO2Me
O
CO
2
Me
O
O
O
OMe
F
X
3mab
3
hab
3ia
3jab: X = Cl, 90% yield, >19:1 dr, 91% ee
3ka
: X = Br, 74% yield, >19:1 dr, 92% ee
lab: X = I, 70% yield, >19:1 dr, 88% ee
68% yield, 13:1 dr
80% yield, >19:1 dr
93% ee
b
99% yield, 15:1 dr
92% ee
93% ee
3
a
Unless otherwise noted, the reactions were carried out with G-5·HBr (10 mol%),
CuBr (20 mol%), 5 Å MS (20 mg), 1/TMSCN/ BuOH (1/1/1, 1.2 equiv) in CH
mL) at 30 °C for 2 h, then 2a (0.10 mmol) was added at -30 °C and reacted at -
0 °C for 24 h. Isolated yield. EE and dr were determined by HPLC or UPC and
t
2
Cl
2
(0.5
2
3
of CuBr with 5 Å MS (entry 8). Lowering the reaction NMR analysis.
temperature in the Michael addition step led to an increase of details. c With 2a (5.0 mmol), and 5 Å MS (1.0 g) in CH
b
CuBr (20-100 mol%), DABCO (0.3-0.5 equiv), see the ESI for
Cl (25.0 mL).
2
2
2
| J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 3 of 4
Please d oC hn eo mt Ca do mj u ms t margins
Journal Name
COMMUNICATION
Table 3 Substrate scope of the N-arylmaleimides 2a
N
2
CuBr/G*-HBr
Gs*-HBr
CN
CO2Me
View Article Online
Ph
CO
2
Me
O
Ph
+
DOI: 10.1039/C
c
9
at
C
*
C09521G
O
O
1a
(Gs* = G+H
)
N
N
2
G-5 •HBr (10 mol%)
O
D
O
Ph
CuBr (20 mol%)
Ph
N
TMSCN
t
BuOH
R2
R2
N
Gs*Br
N
Cu
Ph
CO
2
Me
5
Å MS, CH
Cl
o
CN
Ph
2
2
o
, 30 C, 2 h,
O
O
Ph
N
H
−
CuL*
CN
Then 30 C, 24 h
O
O
Ph
CO2Me
2a
N
C
MeO
ab-3am
2
C
A
O
CO
2
Me
1a
2
Gs*HBr-
Ph
3
NC
Ph
O Cu
CCDC 1901489
3aa
Ph
CO
2
Me
B'
H
OMe
C
CN
H
HCN
TMSCN
Entry
2: R2
2b: 4-MeC
2c: 4-MeOC
2d: 4-EtC
2e: 4-EtOC
2f: 4-iPrC
2g: 4-FC
2h: 4-ClC
2i: 4-BrC
2j: 4-IC
2k: 2-FC
Yield (%)
62 (3ab)
70 (3ac)
73 (3ad)
65 (3ae)
72 (3af)
78 (3ag)
68 (3ah)
65 (3ai)
78 (3aj)
73 (3ak)
85 (3al)
65 (3am)
36 (3an)
54 (3ao)
nr (3ap)
dr
ee (%)
92
92
93
93
92
92
93
93
93
93
93
91
72
50
—
NC
Ph
H-transfer
trace free G-5
Ph
CO
2
Me
tBuOH
Gs*HBr
G*/CuL*
1
2
3
4
5
6
7
8
9
6
H
6 4
H
6 4
H
H
6 4
4
>19:1
16:1
>19:1
>19:1
>19:1
19:1
16:1
16:1
16:1
11:1
>19:1
16:1
7:1
CO
2
Me
B
4a
Cu
Scheme 3 Proposed catalytic cycle.
H
6 4
In order to clarify the multicomponent reaction mechanism,
we tried the control experiments of initial cyanation insertion
reaction and the sequent Michael addition reaction (Scheme 2).
It was found that CuBr in a catalytic amount was sluggish for
hydrocyanation using TMSCN as the cyano-source.9l The
addition of guanidinium salt could dramatically accelerate such
an insertion reaction, better than guanidine G-5 (Scheme 2, b
and c). The isolated cyano-2-phenylacetate 4a was subjected
into the Michael reaction with maleimide 2a under different
reaction conditions (Scheme 2, d-g). We found that guanidine
G-5 along could promote the addition reaction with high yield
and stereoselectivity, but the reactions were inert in the
6
H
4
6
H
4
6 4
H
6
H
4
1
1
1
1
1
1
0
1
2
3
4
5
6
H
4
2l: 2-MeC
H
6 4
2m: 3-FC
2n: Bn
2o: Me
2p: H
H
6 4
5:1
—
a
As same as the condition in footnote a in Table 2.
Taking into account the practical application of the catalyst presence of catalytic amount of CuBr or guanidinium salt. In
system, the gram-scaled synthesis of 3aa was performed. connection with condition of the four-component reaction, we
Under the optimal reaction conditions, the reaction of 5 mmol proposed that the asymmetric relay catalysis is under the
of maleimide 2a reacted well to afford the desired adduct 3aa control of chiral G-5•HBr/CuBr catalyst, rather than CuBr/G-5
in 76% yield with 95% ee and 13:1 dr. The absolute dual catalysis. In connection with the experiment procedure,
configuration of the product 3aa was determined to be (1S, 2R) this multi-component reaction involved in two kinetically
1
3
by X-ray crystallography analysis (see the ESI for details).
Then, we turned our attention to investigate the scope of
different steps.
In this case, the exact structures of the catalyst resting/
maleimides. As shown in Table 3, N-arylmaleimides 2b-2m active state are yet to be studied. We previously have
bearing various aryl groups with different electronic properties discovered a chiral guanidinium dimeric copper(I) cluster forms
efficiently underwent the tandem reaction, delivering N- from the mixture of guanidinium salt and copper(I) salt.1
0f,14
It
substituted phenylpyrrolidine-2,5-diones 3ab-3am with was proposed that such a kind of chiral ion pair might act as
vicinalquaternary-tertiary stereocenters in moderate to good the catalyst precursor. As shown in Scheme 3, the copper salt
yields (62-85%) with generally excellent diastereoselectivities can form the copper(I) carbene
and enantioselectivities (11:1->19:1 dr, 91-93% ee; entries 1- hydrocyanation reaction to generate the cyanomethyl copper
2). In addition, other maleimides such as N-methyl, and N- intermediate . Because the catalyst system is disable for the
benzyl were examined, both the yield and stereoselectivitiy Michael reaction between 4a and maleimide 2a, the copper-
dropped a little (entry 13 and 14). The N-H maleimide 2p could bonded species or other species B’ or might be the active
not participate in the Michael cascade reaction (entry 15).
nucleophile to perform the following addition reaction. The
sulfonamide unit of the guanidinium salt Gs might active the
A, which undergoes
1
B
B
C
-
5
N2
CN
maleimide 2a via hydrogen bonding. Then, a diastereo- and
enantioselective conjugate addition occurs to yield the
cat
tBuOH
TMSCN
Ph
2
CO Me
Ph
CO2Me
Å MS, CH2Cl2, 30 oC, 2 h
(1)
5
1a
4a
intermediate
protonation.
D, generating the final product 3aa after
(
a) CuBr (20 mol%)
3% yield
21% yield
88% yield
(
b) G-5 (10 mol%), CuBr (20 mol%)
(
c) G-5 •HBr (10 mol%), CuBr (20 mol%)
In summary, we have successfully developed an efficient
four-component hydrocyanation/Michael reaction of -aryl
O
O
CN
α
cat
N
Ph
Ph
N
(2)
Ph
CO2Me
Cl2, 30 oC, 12 h
5 Å MS, CH2
CN
CO2Me
diazoesters, TMSCN, tert-butanol, and N-arylmaleimides. The
cyanide-containing pyrrolidine-2,5-dione derivatives could be
obtained in the presence of a chiral guanidinium salt and CuBr
catalyst with good yields and excellent diastereo- and
enantioselectivities. Further applications of the catalyst system
of chiral guanidine or guanidinium salt with metal salt system
in the asymmetric reactions are still underway.
O
O
Ph
4a
2a
3aa
(
d) G-5 •HBr (10 mol%), CuBr (20 mol%)
e) G-5 •HBr (10 mol%)
no reaction
trace, 9:1 dr, 0/0% ee
(
(
f) G-5 (10 mol%)
76% yield, >19:1 dr, 91% ee
10% yield, 86:14 dr, 0/0% ee
(
g) G-5 •HBr (10 mol%), CuBr (20 mol%),
TMSCN/
tBuOH (1.0 equiv)
Scheme 2 Control experiments.
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 3
Please do not adjust margins

Please d oC hn eo mt Ca do mj u ms t margins
Page 4 of 4
COMMUNICATION
We acknowledge the National Natural Science Foundation
Journal Name
Zhou, J. C. Wang, J. H. Wei, Z. J. Xu, Z. Guo, K. HVi.ewLoAwrticlaenOdnliCne.
M. Che, Angew. Chem., Int. Ed., 2012, 51, 11376; (h) L. Ren,
DOI: 10.1039/C9CC09521G
of China (No. 21625205) for financial support.
X. L. Lian and L. Z. Gong, Chem. – Eur. J., 2013, 19, 3315; (i) D.
Zhang, L. L. Lin, J. Yang, X. H. Liu and X. M. Feng, Angew.
Chem., Int. Ed., 2018, 57, 12323.
Conflicts of interest
There are no conflicts to declare.
7
8
9
Y. Tang, J. Xu, J. Yang, L. L. Lin, X. M. Feng and X. H. Liu, Chem,
2
018, 4, 1658.
X. X. Lv, Z. H. Kang, D. Xing and W. H. Hu, Org. Lett., 2018, 20
843.
,
4
(a) M. Y. Hu, C. F. Ni and J. B. Hu, J. Am. Chem. Soc., 2012,
134, 15257; (b) X. Q. Hu, J. B. Han and C. P. Zhang, Eur. J. Org.
Chem., 2017, 324; (c) M. Y. Hu, Q. Q. Xie, X. J. Li, C. F. Ni and J.
B. Hu, Chin. J. Chem., 2016, 34, 469; (d) X. Wang, Y. J. Zhou, G.
J. Ji, G. J. Wu, M. Li, Y. Zhang and J. B. Wang, Eur. J. Org.
Chem., 2014, 3093; (e) Q. Lefebvre, E. Fava, P. Nikolaienko
and M. Rueping, Chem. Commun., 2014, 50, 6617; (f) M. Y.
Hu, J. Rong, W. J. Miao, C. F. Ni, Y. X. Han and J. B. Hu, Org.
Lett., 2014, 16, 2030; (g) Y. F. Liu, X. X. Shao, P. P. Zhang, L.
Lu and Q. L. Shen, Org. Lett., 2015, 17, 2752; (h) C. Matheis,
T. Krause, V. Bragoni and L. J. Goossen, Chem. – Eur. J., 2016,
Notes and references
1
(a) B. M. Trost, Angew. Chem., Int. Ed., 1995, 34. 259; (b) H.
Bienaymé, C. Hulme, G. Oddon and P. Schmitt, Chem. – Eur.
J., 2000, 6, 3321; (c) J. Zhu, H. Bienaymé, Multicomponent
Reactions, Wiley, Weinheim, Germany, 2005; (d) A. Dömling,
Chem. Rev., 2006, 106, 17; (e) A. Dömling and I. Ugi, Angew.
Chem., Int. Ed., 2000, 39, 3168; (f) E. Ruijter, R. Scheffelaar
and R. V. A. Orru, Angew. Chem., Int. Ed., 2011, 50, 6234; (g)
B. Ganem, Acc. Chem. Res., 2009, 42, 463.
For reviews, see: (a) D. J. Ramon and M. Yus, Angew., Chem.,
Int. Ed., 2005, 44, 1602; (b) A. Dondoni and A. Massi, Acc.
Chem. Res., 2006, 39, 451; (c) J. Yu, F. Shi and L. Z. Gong, Acc.
Chem. Res., 2011, 44, 1156; (d) C. D. Graaff, E. Ruijter and R.
V. A. Orru, Chem. Soc. Rev., 2012, 41, 3969; (e) Q. Wang,D. X.
2
22, 12270; (i) M. Lübcke, W. M. Yuan and K. J. Szabó, Org.
Lett., 2017, 19, 4548; (j) Z. K. Zhang, Z. Sheng, W. Z. Yu, G. J.
Wu, R. Zhang, W. D. Chu, Y. Zhang and J. B. Wang, Nat.
Chem., 2017, 9, 970; (k) G. F. Zha, J. B. Han, X. Q. Hu, H. L.
Qin, W. Y. Fang and C. P. Zhang, Chem. Commun., 2016, 52
,
Wang,M. X. Wang and J. P. Zhu, Acc. Chem. Res., 2018, 51
,
,
,
7
7
458; (l) E. J. Park, S. Lee and S. Chang, J. Org. Chem., 2010,
1
5
4
290; (f) C. Hulme and V. Gore, Curr. Med. Chem., 2003, 10
1; (g) B. B. Toure and D. G. Hall, Chem. Rev., 2009, 109
439.
5, 2760; (m) H. H. San, C. Y. Wang, H. P. Zeng, S. T. Fu, M.
Jiang and X. Y. Tang, J. Org. Chem., 2019, 84, 4478.
1
0 For selected examples, see: (a) Y. Zhu, X. H. Liu, S. X. Dong, Y.
H. Zhou, W. Li, L. L. Lin and X. M. Feng, Angew. Chem., Int.
Ed., 2014, 53, 1636; (b) Y. Tang, Q. G. Chen, X. H. Liu, G.
Wang, L. L. Lin and X. M. Feng, Angew., Chem. Int. Ed., 2015,
, 9512; (c) F. Tan, X. H. Liu, X. Y. Hao, Y. Tang, L. L. Lin and
X. M. Feng, ACS Catal., 2016, , 6930; (d) Q. G. Chen, Y. Tang,
3
For selected reviews, see: (a) Y. Qin, L. H. Zhu and S. Z. Luo,
Chem. Rev., 2017, 117, 9433; (b) D. F. Chen, Z. Y. Han, X. L.
Zhou and L. Z. Gong, Acc. Chem. Res., 2014, 47, 2365; (c) C.
Zhong and X. D. Shi, Eur. J. Org. Chem., 2010, 2999; (d) Z. H.
Shao and H. B. Zhang, Chem. Soc. Rev., 2009, 38, 2745; (e) J.
Park and S. Hong, Chem. Soc. Rev., 20129, 42, 6931; For
selected examples, see: (f) G. M. Sammis, H. Danjo and E. N.
Jacobsen, J. Am. Chem. Soc. 2004, 126, 9968; (g) J. Li, L. L.
Lin, B. W. Hu, P. F. Zhou, T. Y. Huang, X. H. Liu and X. M.
Feng, Angew. Chem., Int. Ed., 2017, 56, 885; (h) Q. Xiong, S. X.
Dong, Y. S. Chen, X. H. Liu and X. M. Feng, Nat. Commun.,
5
4
6
T. Y. Huang, X. H. Liu, L. L. Lin and X. M. Feng, Angew., Chem.
Int. Ed., 2016, 55, 5286; (e) Q. G. Chen, L. H. Xie, Z. J. Li, Y.
Tang, P. Zhao, L. L. Lin, X. M. Feng and X. H. Liu, Chem.
Commun., 2018, 54, 678; (f) S. S. Guo, P. Dong, Y. S. Chen, X.
M. Feng and X. H. Liu, Angew. Chem., Int. Ed., 2018, 57
6852; (g) J. Yang, P. R. Ruan, W. Yang, X. M. Feng and X. H.
Liu, Chem. Sci., 2019, 10, 10305.
,
1
2019, 10, 2116.
For selected reviews, see: (a) G. Maas, Chem. Soc. Rev.,
4
5
1
1
1 (a) X. H. Liu, B. Qin, X. Zhou, B. He and X. M. Feng, J. Am.
Chem. Soc., 2005, 127, 12224; (b) Y. H. Liao, X. L. Liu, Z. J.
Wu, X. L. Du, X. M. Zhang and W. C. Yuan, Adv. Synth. Catal.,
2
2
2
2
004, 33, 183; (b) H. M. L. Davies and J. R. Manning, Nature,
008, 451, 417; (c) Y. Zhang and J. B. Wang, Chem. Commun.,
009, 5350; (d) S. F, Zhu and Q. L. Zhou, Acc. Chem. Res.,
012, 45, 1365; (e) N. R. Candeias, R. Paterna, P. M. P. Gois,
2
011, 353, 1720; (c) Z. W. Ma, Y. Wu, B. Sun, H. L. Du, W. M.
Shi and J. C. Tao, Tetrahedron: Asymmetry, 2013, 24, 7.
2 (a) Z. P. Yu, X. H. Liu, L. Zhou, L. L. Lin and X. M. Feng, Angew.
Chem., Int. Ed., 2009, 48, 5195; (b) S. X. Dong, X. H. Liu, X. H.
Chen, F. Mei, Y. L. Zhang, B. Gao, L. L. Lin and X. M. Feng, J.
Chem. Rev., 2016, 116, 2937; (f) Y. Xia, D. Qiu, and J. B. Wang,
Chem. Rev., 2017, 117, 13810; (g) Y. Y. Ren, S. F. Zhu and Q.
L. Zhou, Org. Biomol. Chem., 2018, 16, 3087.
(a) X. Guo and W. H. Hu, Acc. Chem. Res., 2013, 46, 2427; (b)
M. Tang, D. Xing, M. Q. Cai and W. H. Hu, Chin. J. Org. Chem.,
Am. Chem. Soc., 2010, 132, 10650
Xie, L. L. Lin, X. M. Feng and X. H. Liu, Org. Chem. Front.,
018, , 32; (d) S. X. Dong, X. M. Feng and X. H. Liu, Chem.
; (c) S. Ruan, X. B. Lin, L. H.
2
1
014, 34, 1268; (c) D. Zhang and W. H. Hu, Chem. Rec., 2017,
, 739; (d) M. Y. Wu, W. W. He, X. Y. Liu and B. Tan, Angew.
2
5
7
Soc. Rev., 2018, 47, 8525; (e) X. H. Liu, S. X. Dong, L. L. Lin
and X. M. Feng, Chin. J. Chem., 2018, 36, 791; (f) W. D. Cao,
X. H. Liu and X. M. Feng, Chin. Chem. Lett., 2018, 29, 1201; (g)
L. H. Xie, S. X. Dong, Q. Zhang, X. M. Feng and X. H. Liu,
Chem. Commun., 2019, 55, 87.
Chem., Int. Ed., 2015, 54, 9409; (e) D. Zhang, H. Qiu, L. Q.
Jiang, F. P. Lv, C. Q. Ma and W. H. Hu, Angew. Chem., Int. Ed.,
2
013, 52, 13356; (f) S. F. Yu, X. Fu, G. X. Liu, H. Qiu and W. H.
Hu, Acta Chim. Sinica., 2018, 76, 895; (g) F. M. Liao, Y. Du, F.
Zhou, J. Zhou, Acta Chim. Sinica., 2018, 76, 862.
1
1
3 CCDC 1901489 (3aa).
6
For selected examples, see: (a) W. H. Hu, X. F. Xu, J. Zhou, W.
J. Liu, H. X. Huang, J. Hu, L. P. Yang and L. Z. Gong, J. Am.
Chem. Soc., 2008, 130, 7782; (b) X. Zhang, H. X. Huang, X.
Guo, X. Y. Guan, L. P. Yang and W. H. Hu, Angew. Chem., Int.
Ed., 2008, 47, 6647; (c) X. Y. Guan, L. P. Yang and W. H. Hu,
Angew. Chem., Int. Ed., 2010, 49, 2190; (d) J. Jiang, H. D. Xu, J.
B. Xi, B. Y. Ren, F. P. Lv, X. Guo, L. Q. Jiang, Z. Y. Zhang, and W.
H. Hu, J. Am. Chem. Soc., 2011, 133, 8428; (e) D. Zhang, J.
4 (a) H. X. Huang, X. Guo and W. H. Hu, Angew. Chem., Int. Ed.,
2
007, 46, 1337; (b) X. Y. Cui, Y. C. Ge, S. M. Tan, H. Jiang, D.
Tan, Y. P. Lu, R. Lee and C. H. Tan, J. Am. Chem. Soc., 2018,
1
40, 8448
M. L. Ma, D. Xing and W. H. Hu, Chem. Commun., 2018, 54
2.
;
(c) G. K. R. Alavala, F. Sajjad, T. D. Shi, Z. H. Kang,
,
1
Zhou, F. Xia, Z. H Kang and W. H. Hu, Nat. Commun., 2015,
6
,
5
801; (f) H. Qiu, M. Li, L. Q. Jiang, F. P. Lv, L. Zan, C. W. Zhai,
M. P. Doyle and W. H. Hu, Nat. Chem., 2012,
4
, 733. (g) C. Y.
4
| J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins