Enantioselective zinc-mediated conjugate alkynylation of saccharin-derived 1-: Aza -butadienes

Article abstract of DOI:10.1039/d0cc04221h

The enantioselective 1,4-alkynylation of conjugated imines derived from saccharin with aryl- and alkyl-substituted terminal alkynes has been achieved. The reaction mediated by diethylzinc in the presence of a catalytic amount of a bis(hydroxy)malonamide chiral ligand provides the corresponding imines bearing a propargylic stereocenter with moderate yields and fair to excellent enantioselectivities. This journal is

Full text of DOI:10.1039/d0cc04221h

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: G. Blay, A. Castilla,
D. Sanz, A. Sanz-Marco, C. Vila, M. C. Muñoz and J. R. Pedro, Chem. Commun., 2020, DOI:
10.1039/D0CC04221H.
Volume 54
This is an Accepted Manuscript, which has been through the
Number
January 2018
Pages 1-112
1
4
Royal Society of Chemistry peer review process and has been
accepted for publication.
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 doChneomt Cadomjumst margins
View Article Online
DOI: 10.1039/D0CC04221H
COMMUNICATION
Enantioselective zinc-mediated conjugate alkynylation of
saccharin-derived 1-aza-butadienes
Gonzalo Blay,*a Alvaro Castilla,a David Sanz,a Amparo Sanz-Marco,a Carlos Vila,a M. Carmen
Received 00th January 20xx,
Accepted 00th January 20xx
Muñoz,b José R. Pedro*a
DOI: 10.1039/x0xx00000x
The enantioselective 1,4-alkynylation of conjugated imines derived enantioselective alkynylation of conjugated carbonyl
from saccharin with aryl- and alkyl- substituted terminal alkynes compounds6 and nitroalkenes7 under a variety of metal catalysis
has been achieved. The reaction mediated by diethylzinc in the (Scheme 1b). However, despite these advances some
presence of a catalytic amount of a bis(hydroxy)malonamide chiral limitations still remain. For instance, most of the reported
ligand provides the corresponding imines bearing a propargylic procedures are appropriate for aryl- or trialkylsilyl- acetylenes
stereocenter with moderate yields and fair to excellent but provide low enantioselectivities with alkyl-substituted
enantioselectivities.
alkynes.5 Furthermore, developing conditions for the regio- and
enantioselective alkynylation of other 1,4-acceptors, besides
conjugated carbonyls and nitroalkenes, would be highly
desirable.
The C C triple bond is present in the structures of many natural
−
products and other organic compounds of interest in
biochemistry and material science.1 Furthermore, alkynes are
versatile building blocks in synthetic organic chemistry that can
undergo a broad range of transformation providing access to
different functional groups and structural motifs.2 Accordingly,
Recently, α,β-unsaturated imines (1-aza-butadienes), the
nitrogen analogues of enones, have been explored as Michael
acceptors in enantioselective reactions.8,9 However, although a
synthesis of pyridines and pyrroles involving the copper-
catalyzed conjugate addition of alkyl propiolates to N-sulfonyl
aza-dienes has been reported,10 there are no literature
precedents on the enantioselective conjugate alkynylation of
α,β-unsaturated imines to give chiral β-alkynyl imines bearing a
propargylic stereocenter. Here, we describe our results on this
elusive reaction (Scheme 1c), with special attention to the
challenging aliphatic alkynes, affording chiral β-alkynyl imines
the development of procedures to introduce a C−C triple bond
in organic molecules is an important goal for many synthetic
chemists. Among the different methodologies developed, those
that exploit the acidic character of terminal alkynes are
especially appealing. Thus, deprotonation of terminal alkynes
with stoichiometric or catalytic amounts of base (in the
presence of metal catalyst) provides nucleophilic metal
alkynylides, which can react with carbon-based electrophiles to
work
Previous
give internal alkynes with concomitant formation of a new C−C
and
Enantioselective
of carbonyl
alkynylation
imines
compounds
a)
bond and, sometimes, of a new propargylic stereogenic center.
In this context, considerable efforts have been devoted to the
enantioselective alkynylation of carbonyl compounds3 and
imines4 to give propargylic alcohols and amines, respectively
(Scheme 1a). On the other hand, the enantioselective
R3
Asymmetric
catalysis
X
XH
R1 R2
R3
R1 R2
*
=
X
NR
O,
,
α
Enantioselective
of
-unsaturated carbonyl
compounds
β
b)
alkynylation
and
nitroalkenes
O
R2
*
O
alkynylation of electrophilic C−C double bonds conjugated with
R1
R1
R2
R2
Asymmetric
catalysis
electron-withdrawing groups has constituted a bigger challenge
due to their lower electrophilicity and regioselectivity issues.5
Nevertheless, considerable success has been obtained in the
R3
R2
*
R3
O2N
work
O2N
R3
R2
This
,
α
Enantioselective
of
alkynylation
-unsaturated imines
β
c)
O
O
O
Asymmetric
catalysis
S
N
O
S
a.Departament de Química Orgànica, Facultat de Química, Universitat de València,
C/ Dr. Moliner 50, 46100-Burjassot, Spain.
N
R2
R1
b.Departament de Física Aplicada, Universitat Politècnica de València, Camí de
Vera s/n, E-46022 València, Spain.
R1
Scheme 1 Enantioselective addition of terminal alkynes
Electronic Supplementary Information (ESI) available: [details of any supplementary
information available should be included here]. See DOI: 10.1039/x0xx00000x
Please do not adjust margins

Please do not adjust margins
ChemComm
Page 2 of 4
COMMUNICATION
Journal Name
with excellent enantioselectivities.
bis(hydroxy)oxamide (L4) and several bis(hydroxyV)miewaAlortinclaemOnildinee
L8) were tested as chiDraOlI:l1ig0.a1n03d9s/.D0TChCe04m22o1sHt
Preliminary studies for the conjugate alkynylation of α,β- derivatives (L5
unsaturated imines were carried out using the addition of significative results are shown in Table 1 (see also SI). Ligands
phenylacetylene to the N-tosylimine of chalcone mediated by derived from 2,2-diethylmalonic acid and 1,1,2-
-
zinc. However, although the applied conditions11 led to the triarylaminoethanol (L6 and L7) provided the best results with
conjugate alkynylation product with fair levels of similar performance for both ligands, compound 3aa being
enantioselectivity, this was ineluctably obtained as an obtained in ca 50% yield and 71% ee and 72% ee, respectively
imine/enamine isomeric mixture (See SI). To avoid this (Table 1, entries 6 and 7). Further optimization was performed
drawback, saccharin-derived imines were chosen as substrates with ligand L7. The effect of the catalyst load was examined.
as we anticipated the preferential formation of the imine with Increasing it to 30 mol% brought about a decrease of both yield
the endocyclic double bond.12 To begin with the optimization and enantiomeric excess (Table 1, entry 9). On the other hand,
process, we studied the addition of phenylacetylene (2a) to only a slight decrease in the ee and yield was observed when
saccharin-derived imine 1a (Table 1).11
the catalyst loading was reduced to 10 mol% (Table 1, entry 7 vs
We initially tested the conditions developed in our group for the entry 10). Increasing the amount of diethylzinc from 2 to 4
zinc-mediated conjugate alkynylation of unsaturated carbonyl equivalents in the presence of 10 mol% of L7 allowed to
compounds.11 Under the initial conditions, the reactive system improve the ee of the reaction up to 80% (Table 1, entry 11).
was prepared by heating a solution of ligand (20 mol%), alkyne Dimethylzinc was also tested but provided lower results than
2a (7.5 equiv.) and diethylzinc (2 equiv.) in toluene to 70 °C for diethylzinc (Table 1, entry 12 vs 11). Finally, reducing the
1 hour followed by addition of the imine 1a after cooling to amount of alkyne 2a to 5 equivalents increased the ee to 85%,
room temperature. Dihydroxybiaryl (L1
,
L2), mandelamide (L3), while keeping the yield (Table 1, entry 13).
Under the best conditions available (Table 1, entry 13) we
studied the scope of the enantioselective conjugate
alkynylation of imines (Table 2). First, we performed the
addition of arylacetylenes to imines . The results of the
reaction were highly dependent on both the substituent on the
β position of the double bond in compounds and on the aryl
group of the alkyne . In most of the cases the addition products
were obtained with fair yields‡ and enantiomeric excesses
Table 1 Optimization of reaction conditions.a
O
O
Ph
*
1
O
H
+
S
O
N
S
1
R Zn L
,
2
N
Ph
toluene
Ph
Ph
1
1a
2a
Ph Ph
3aa
2
3
O
(Table 2, entries 1-11). Interestingly, the addition of 4-phenyl-1-
butyne (2d) to imine 1a under the optimized conditions
provided compound 3ad with 90% ee together with some
racemic ethylation product, which could be avoided by reducing
OH
OH
Ph
OH
Ph
N
O
H
O
H
H
L3
L1
L2
R
O
R
Table
2 Conjugate addition of aryl-substituted terminal acetylenes 2 to
O
O
O
O
O
unsaturated imines 1 a
.
Ph
Ph
Ph
Ph
Ph
Ph
Ph
NH HN
Ph
Ph
Ph
HN
NH
Ph
Ar
Ar
NH HN
Ph
R2
Ph
Ph
O
Ar
Ar
O
O
R2
S
HO
OH
O
HO
OH
HO
OH
=
=
=
N
S
L7
Et Zn
,
2
N
+
L4
=
L5
L6
L7
L8
R
R
R
Me, Ar Ph
rt
toluene,
R1
H
=
Et, Ar Ph
R1
=
Et, Ar
4-ClC6
H4
2
1
3
L
2a
Et2Zn
Yield
(%)
22
48
65
49
48
50
53
54
27
41
53
50
47
ee
Entry
1
R1
2
R2
3
Yield ee
Entry
t (h)
(mol%) (equiv.) (equiv.)
(%)b
0
(%) (%)b
1
2
3
4
5
6
7
8
9
10
11
12c
13
L1 (20)
L2 (20)
L3 (20)
L4 (20)
L5 (20)
L6 (20)
L7 (20)
L8 (20)
L7 (30)
L7 (10)
L7 (10)
L7 (10)
L7 (10)
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
5
2
2
2
2
2
2
2
2
2
2
4
4
4
3
3
3
3
3
3
3
3
3
3
3
3
3
1
2
3
4
5
6
7
8
9
a
b
c
d
e
f
g
h
i
a
a
a
Ph
p-BrC6H4
a
a
a
a
a
a
a
a
a
b
c
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
3aa
3ba
3ca
3da
3ea
3fa
3ga
3ha
3ia
47
59
40
33
36
35
35
49
84
43
46
50
85
69
33
58
53
71
83
70
35
83
54
90
-22
26
10
p-MeOC6H4
p-MeC6H4
o-MeC6H4
m-MeC6H4
2-naphthyl
2-thienyl
tert-butyl
Ph
-65
-71
-72
30
-38
-67
-80
-58
-85
10
11
12c
p-ClC6H4
p-MeOC6H4
PhCH2CH2
3ab
3ac
3ad
Ph
Ph
d
a
1
(0.125 mmol),
2
(0.625 mmol), 1.5 M Et2Zn in toluene (0.50 mmol), L7
a 1a (0.125 mmol), 2a, 1.5 M Et2Zn in toluene, L, toluene (1.5 mL), rt. b Determined
by HPLC with chiral stationary phases. Different sign indicates opposite
enantiomers. c Me2Zn was used instead of Et2Zn.
b
(0.025 mmol), toluene (1.5 mL), rt, 3 h. Determined by HPLC with chiral
stationary phases. c Et2Zn (0.25 mmol)
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
ChemComm
Please do not adjust margins
Journal Name
COMMUNICATION
the amount of Et2Zn to 2 equivalents (Table 2, entry 12). This is
a remarkable result, since historically alkyl acetylenes tend to
give lower enantioselectivities than aryl acetylenes.5 In the view
of these promising results, we decided to further investigate the
addition of alkyl-substituted terminal acetylenes. The
performance of ligands L6 and L7 was re-evaluated in the
addition of 4-phenyl-1-butyne (2d) to imine 1a. In this case L6
gave better result, allowing to obtain compound 3ad in 68%
View Article Online
DOI: 10.1039/D0CC04221H
yield and 95% ee (Table 2, entry 12 vs Table 3, entry 1). With L6
,
we studied the addition of a number of alkyl-substituted
terminal acetylenes to several imines (Table 3).
Besides 4-phenyl-1-butyne (2d), the reaction could be carried
out with other alkynes bearing a fully alkyl chain such as 1-
hexyne (2e), the functionalized 6-chloro-1-hexyne (2f), the
Figure 1 Ortep plot for the X-ray structure of compound 3bg. The thermal
ellipsoids are drawn at the 50% probability level. Flack parameter 0.017(6).
challenging cyclopropylacetylene
functionalized alkynes bearing ester, benzyl ether or aryl ether
groups (2h ). Regarding the conjugated imine partner, the aryl
(2g), as well as other
The conjugate alkynylation of 1a with 4-phenyl-1-butyne (2d
)
-
j
was scaled up to 1.25 mmol of 1a providing the expected
product 3ad with good yield and some erosion of
enantioselectivity, but still with high 88% ee (Table 3, entry 18).
Compound 3bg (Table 3, entry 10) could be crystallized and
subjected to X-ray analysis, what allowed to establish the
configuration of the stereogenic center as S (Figure 1).§ The
group attached to the β-carbon of the double bond was
amenable to variation, allowing the presence of electron-
withdrawing or electron-donating groups at either the ortho-,
metha- or para-positions of the phenyl ring. In all the cases, the
alkynylated imines were obtained with excellent
enantioselectivities (82-97% ee), especially when a para-
substituted aryl group was used (Table 3).
absolute stereochemistry of all compounds
3 was assigned by
analogy upon the assumption of a uniform stereochemical
pathway.
Scheme 2 shows some transformations on compound 3ae that
Table
3 Conjugate addition of alkyl-substituted terminal acetylenes 2 to
unsaturated imines 1 a
.
R2
show the potential application of compounds 3 in the synthesis
of optically active benzosultams. Thus, selective reduction of
the imine could be achieved by treatment with sodium
O
O
O
R2
S
O
N
S
L6
Et Zn
,
2
N
+
rt
toluene,
R1
H
R1
borohydride in THF to give alkyne
mixture of two diastereomers without erosion of the
enantiomeric excess. On the other hand, compound was
4 in 80% yield as a 69:31
2
1
3
5
Entry
1
R1
Ph
p-BrC6H4
Ph
p-BrC6H4
p-MeC6H4
Ph
p-BrC6H4
p-MeC6H4
Ph
p-BrC6H4
p-MeOC6H4
p-MeC6H4
o-MeC6H4
m-MeC6H4
Ph
2
R2
3
Yield ee
(%) (%)b
obtained in 75% yield, as a 74:26 diastereomer mixture without
loss of enantiomeric excess, after simultaneous reduction of the
triple bond and the imine by catalytic hydrogenation on 10%
Pd/C.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18c
a
b
a
b
d
a
b
d
a
b
c
d
e
f
a
a
a
a
d
d
e
e
e
f
PhCH2CH2
PhCH2CH2
butyl
3ad
3bd
3ae
3be
3de
3af
3bf
3df
3ag
3bg
3cg
3dg
3eg
3fg
68
35
44
38
42
48
36
58
61
45
69
69
55
64
63
66
59
56
95
96
88
97
92
96
93
91
93
96
93
93
85
82
93
99
80
88
butyl
butyl
Ph
Ph
O
O
O
O
Cl(CH2)4
Cl(CH2)4
Cl(CH2)4
cyclopropyl
cyclopropyl
cyclopropyl
cyclopropyl
cyclopropyl
cyclopropyl
PhCO2CH2
S
S
N
NH
f
f
NaBH4
THF
80%
g
g
g
g
g
g
h
i
Ph
Ph
3ae
4
=
dr 69:31
ee=
95%
ee major
=
95%
Ph
O
S
N
O
O
O
Ph
S
NH
3ah
H
2, Pd/C
Ph
Ph
Ph
p-MeOC6H4O(CH2)4 3ai
MeOH
75%
j
d
PhCH2OCH2
PHCH2CH2
3aj
3ad
Ph
Ph
3ae
ee=
5
dr =74:26
ee major
95%
a 1 (0.125 mmol), 2 (0.625 mmol), 1.5 M Et2Zn in toluene (0.17 mL, 0.25 mmol), L6
(0.0125 mmol), toluene (1.5 mL), rt, 3 h. Determined by HPLC with chiral
=
94%
b
Scheme 2 Synthetic transformations of compound 3ae.
stationary phases. c Reaction carried out with 1.25 mmol of 1a.
In summary, we have reported the first example of
enantioselective conjugate alkynylation of -unsaturated
α.β
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 3
Please do not adjust margins

Please do not adjust margins
ChemComm
Page 4 of 4
COMMUNICATION
Journal Name
4
5
Reviews: (a) G. Blay, A. Monleón and J. R. Pedro, Curr. Org.
Chem., 2009, 13, 1498; Recent example: (b) R.-VRie.wLiAurt,icLle.OZnhliune,
J.-P. Hu, C.-J. Lu, J.-R. Gao, Y. LanDOanI:d10.Y10.-3X9./DJ0iaC,C0C4h2e2m1H.
Commun., 2017, 53, 5890.
imines (1-aza-butadienes). A reactive system formed by a
terminal
bis(hydroxy)malonamide allowed the enantioselective
alkynylation of C C double bonds conjugated with saccharin-
alkyne,
diethylzinc
and
a
chiral
−
(a) G. Blay, J. R. Pedro and A. Sanz-Marco, Synthesis, 2018, 50
,
derived imines to give the corresponding alkynylated imines
bearing a propargylic stereocenter. The reaction can be
performed with terminal alkynes of different characteristics
and, remarkably, it is most convenient for alkyl-substituted
alkynes. The results anticipated the potential application of this
catalytic system to other unsaturated imines sucha as chalcone
imines. Research with this regard is underway in our laboratory.
This work was supported by the Agencia Estatal de Investigación
and Fondo Europeo de Desarrollo Regional-EU (Grant CTQ2017-
84900-P). We gratefully thank the access to NMR and MS
facilities from the SCSIE-UV. C. V. thanks the Spanish
Government for a Ramon y Cajal contract (RyC-2016-20187). A.
S.-M. thanks the Generalitat Valenciana and FEDER-EU for a
post-doctoral grant (APOST/2016/139) and the Spanish
government for a Juan de la Cierva Contract (IJC2018-036682-
I).
3281; (b) N. Kumagai and M. Shibasaki, Catalytic Conjugate
Additions of Alkynes in Modern Alkyne Chemistry; Trost, B. M.;
Li, C.-J., Eds.; Wiley-VCH: Weinheim, 2015, 173; (c) S. Fujimori,
T. F. Knöpfel, P. Zarotti, T. Ichikawa, D. Boyall and E. M.
Carreira, Bull. Chem. Soc. Jpn., 2007, 80, 1635.
6
Copper: (a) T. F. Knopfel, P. Zarotti, T. Ichikawa and E. M.
Carreira, J. Am. Chem. Soc., 2005, 127, 9682; (b) R. Yazaki, N.
Kumagai and M. Shibasaki, J. Am. Chem. Soc., 2010, 132
,
10275; (c) A. Sanz-Marco, A. García-Ortiz, G. Blay, I. Fernández
and J. R. Pedro, Chem. Eur. J., 2014, 20, 668; (d) A. Sanz-
Marco, A. García-Ortiz, G. Blay and J. R. Pedro, Chem.
Commun., 2014, 50, 2275; (e) L. Meng, K. Y. Ngai, X. Chang, Z.
Lin and J. Wang, Org. Lett., 2020, 22, 1155; (f) L. G. DeRatt, M.
Pappoppula and A. Aponick, Angew. Chem. Int. Ed., 2019, 58
,
8416; Rhodium: (g) T. Nishimura, T. Kato, K. Takatsu, R.
Shintani and T. Hayashi, J. Am. Chem. Soc., 2007, 129, 14158;
(h) K.-L. Choo and M. Lautens, Org. Lett., 2018, 20, 1380; (i) E.
Fillion and A. K. Zorzitto, J. Am. Chem. Soc., 2009, 131, 14608;
Cobalt: (j) T. Nishimura, T. Sawano, K. Ou and T. Hayashi,
Chem. Commun., 2011, 47, 10142.
7
8
(a) M. Yamashita, K.-I. Yamada and K. Tomioka, Org. Lett.,
2005, 12, 2369; (b) T. Nishimura, S. Tokuji, T. Sawano and T.
Hayashi, Chem. Commun., 2010, 46, 6837.
Reviews: (a) B. Groenendaal, E. Ruijter and R. V. A. Orru,
Chem. Commun., 2008, 43, 5474; (b) M. Shimizu, I. Hachiya
and I. Mizota, Chem. Commun., 2009, 874; (c) J.-C. M.
Monbaliu, K. G. R. Masschelein and C. V. Stevens, Chem. Soc.
Rev., 2011, 40, 4708; (d) G. Blond, M. Gulea and V. Mamane,
Curr. Org. Chem., 2016, 20, 2161.
(a) J. Esquivias, R. Gómez Arrayás and J. C. Carretero, J. Org.
Chem., 2005, 70, 7451; (b) M. Espinosa, G. Blay, L. Cardona
and J. R. Pedro, Chem. Eur. J., 2013, 19, 14861 (corrigenda:
Chem. Eur. J., 2013, 19, 17632); (c) S. Gebhardt, C. H. Müller,
J. Westmeier, K. Harms and P. Von Zezschwitz, Adv. Synth.
Catal., 2015, 357, 507; (d) A. Lee and H. Kim, J. Org. Chem.,
2016, 81, 3520; (e) C. Solé, A. Tatla, J. A. Mata, A. Whiting, H.
Gulyás and E. Fernández, Chem. Eur. J., 2011, 17, 14248; (f) M.
Espinosa, G. Blay, L. Cardona, M. C. Muñoz and J. R. Pedro,
Chem. Eur. J., 2017, 23, 14707.
Conflicts of interest
There are no conflicts to declare
Notes and references
‡ In some cases we observed the formation of the conjugate
ethylation product in some extent. This fact together with the low
solubility showed by some of the products may account in part
for the obtained fair yields. The mass balance in three
representative entries (Table 2, entry 1 and Table 3, entries 16
and 17) can be found in the SI.
§ CCDC-1992564 contains the supplementary crystallographic
data for this paper. These data can be obtained free of charge
from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
9
10 Z. Ling, F. Xie, I. D. Gridnev, M. Terada and W. Zhang, Chem.
Commun., 2018, 54, 9446.
11 (a) A. Sanz-Marco, G. Blay, C. Vila and J. R. Pedro, Org. Lett.,
2016, 18, 3538; (b) G. Blay, M. C. Muñoz, J. R. Pedro and A.
Sanz-Marco, Adv. Synth. Catal., 2013, 355, 1071; (c) G. Blay, L.
Cardona, J. R. Pedro and A. Sanz-Marco, Chem. Eur. J., 2012,
18, 12966.
1
2
(a) F. Bohlmann, H. Burkhardt and C. Zdero, Naturally
Occurring Acetylenes, Academic Press: New York, 1973; (b) M.
B. Nielsen, F. Diederich, Chem. Rev., 2005, 105, 1837; (c) K.
West, C. Wang, A. S. Batsanov and M. R. Bryce, Org. Biomol.
Chem., 2008, 6, 1934; (d) D. V. Kuklev, A. J. Domb and V. M.
Dembitsky, Phytomedicine, 2013, 20, 1145; (e) Z.-F. Zhou, M.
Menna, Y.-S. Cai and Y.-W. Guo, Chem. Rev., 2015, 115, 1543.
(a) P. F. Hudrlik and A. M. Hudrlik, in Applications of
Acetylenes in Organic Synthesis, in The Chemistry of the
Carbon-Carbon Triple Bond Part 1; Patai, S., Ed.; Wiley:
Chichester, 1978, 199; (b) Modern Alkyne Chemistry. Catalytic
and Atom Economy Reactions; Trost, B. M.; Li, C.-J. Eds.;
Wiley-VCH: Weinheim, 2015; (c) G. Fang and X. Bi, Chem. Soc.
Rev., 2015, 44, 8124; (d) I.-T. Trotus, T. Zimmermann and F.
Schüth, Chem. Rev., 2014, 114, 1761; (e) R. Chinchilla and C.
Nájera, Chem. Rev., 2014, 114, 1783.
12 For selected catalytic asymmetric examples with this kind of
imines see: (a) Y.-H. Chen, D.-H. Li and Y.-K. Liu, ACS Omega,
2018,
He and Y. Lu, Org. Lett., 2017, 19, 3111; (c) L. Yu, Y. Cheng, F.
Qi, R. Li and P. Li, Org. Chem. Front., 2017, , 1336; (d) Y.-F.
3, 16615; (b) Z. Wang, H. Xu, Q. Su, P. Hu, P.-L. Shao, Y.
4
Zhang, D. Chen, W.-W. Chen and M.-H. Xu, Org. Lett., 2016,
18, 2726; (e) E. Li, H. Jin, P. Jia, X. Dong and Y. Huang, Angew.
Chem. Int. Ed., 2016, 55, 11591; (f) X.-L. He, Y.-C. Xiao, W. Du
and Y.-C. Chen, Chem. Eur. J., 2015, 21, 3443; (g) J. Gu, C. Ma,
Q.-Z. Li, W. Du and Y.-C. Chen, Org. Lett., 2014, 16, 3986; (h)
X. Yin, Y. Zheng, X. Feng, K. Jiang, X.-Z. Wei, N. Gao, Y.-C. Chen,
Angew. Chem. Int. Ed., 2014, 53, 6245.
3
Reviews: (a) B. M. Trost and A. H. Weiss, Adv. Synth. Catal.,
2009, 351, 963; (b) C.-J. Li, Acc. Chem. Res., 2010, 43, 581;
Recent examples: (c) D. Park, C. I. Jette, J. Kim, W.-O. Jung, Y.
Lee, J. Park, S. Kang, M. S. Han, B. M. Stoltz and S.Hong,
Angew. Chem. Int. Ed., 2020, 59, 775; (d) J. Lu, L.-S. Luo, F. Sha,
Q. Li and X.-Y. Wu, Chem. Commun., 2019, 55, 11603; (e) S.
Paria, H.-J. Lee and K. Maruoka, ACS Catal., 2019, 9, 2395.
4 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins