Nitrogen-containing Lewis bases catalyzed highly regio- and stereoselective reactions of allenyl acetates with isatin-derived oximes

Article abstract of DOI:10.1016/j.tet.2013.02.070

Different nitrogen-containing Lewis bases catalyzed reactions of highly reactive allenyl acetates with isatin-derived oximes afforded the corresponding oxime ethers or nitrone derivatives in good to high yields with high regio- and stereoselectivities.

Full text of DOI:10.1016/j.tet.2013.02.070

Tetrahedron 69 (2013) 3593e3607
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Nitrogen-containing Lewis bases catalyzed highly regio- and
stereoselective reactions of allenyl acetates with isatin-derived
oximes
,
a,b,
Yuan-Liang Yang a, Yin Wei b, Qin Xu a , Min Shi
*
*
a Key Laboratory for Advanced Materials and Institute of Fine Chemicals, School of Chemistry & Molecular Engineering, East China University of Science
and Technology, 130 Mei-Long Road, Shanghai 200237, China
b State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Road, Shanghai
200032, China
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 4 January 2013
Received in revised form 4 February 2013
Accepted 10 February 2013
Available online 6 March 2013
Different nitrogen-containing Lewis bases catalyzed reactions of highly reactive allenyl acetates with
isatin-derived oximes afforded the corresponding oxime ethers or nitrone derivatives in good to high
yields with high regio- and stereoselectivities.
Ó 2013 Elsevier Ltd. All rights reserved.
Keywords:
Lewis bases
Isatin-derived oximes
Allenyl acetates
Oxime ethers
Nitrone derivatives
1. Introduction
a,b
-unsaturated esters by Lee and co-workers in 2009,10 may be the
suitable substrate since it involves two highly active moieties. Re-
cently, another investigation on the amine-catalyzed intermolecular
formal [3þ3] cycloaddition reaction using these substrates was re-
ported by Tong and co-workers in 2012.11 In order to make further
investigations on the reactivities of these allenyl acetates, we de-
cided to choose oximes and allenyl acetates as substrates to explore
their reaction outcomes under the similar reaction conditions as
reported by Kwon8s and our group12 (Scheme 1).
Oximes and their derivatives as useful synthons are widely
utilized in organic synthesis,1 since they can be easily transformed
into ketones,2 amides,3 and nitriles.4 They are also significant
feedstocks to synthesize nitrogen-containing heterocyclic com-
pounds by transition-metal5 or Brønsted base6 catalyzed cycliza-
tion. Meanwhile, oximes can be also used as ligands for oxime-
derived palladacycles, which have been proved to be efficient and
versatile in carbonecarbon coupling reactions.7 On the other hand,
2-alkyl-2,3-butadienoates have attracted much attention and many
interesting reaction outcomes have been explored due to their high
reactivities.8
Morita-Baylis-Hillman Carbonates
Moreover, the allylic alkylations of MoritaeBayliseHillman
(MBH) adducts catalyzed by Lewis bases have recently become an
attractive strategy to construct a large variety of multifunctional
compounds.9 Based on these previous investigations, we intend to
use a more reactive species to undergo the Lewis base catalyzed
reactions. We found that the allenyl acetate shown in Fig. 1, which
R
AcO
CO2Et
was first synthesized and used for the synthesis of (E)-a-ethynyl-
2-Alkyl-2,3-butadienoate
* Corresponding authors. Fax: þ86 21 64166128; e-mail address: mshi@mail.-
sioc.ac.cn (M. Shi).
Fig. 1. Highly active allenyl acetates.
0040-4020/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.tet.2013.02.070

3594
Y.-L. Yang et al. / Tetrahedron 69 (2013) 3593e3607
Scheme 1. Different Lewis bases catalyzed reactions of allenyl acetates with isatin-derived oximes.
2. Results and discussion
the presence of nitrogen-containing Lewis base, such as DABCO
(1,4-diazabicyclo[2,2,2]octane). To our delight, the reaction was
conducted in THF catalyzed by DABCO at room temperature for 5 h,
affording highly regio- and stereoselective E-3a in 88% yield (Table
1, entry 4). Subsequently, other nitrogen-containing Lewis bases
were also tested. Using Et3N or DBU (1,8-diazabicyclo[5.4.0]undec-
7-ene) as catalyst, the yield of 3a decreased to 67% and 31%, re-
spectively (Table 1, entries 6 and 10). Meanwhile, if using pyridine
as the catalyst, the yield decreased remarkably to 21% and
a byproduct 4a was obtained in 37% yield (Table 1, entry 5; for the
structure of 4a, see Table 3, entry 1). The reaction also proceeded
fairly smoothly in the presence of DMAP (4-(N,N-dimethylamino)
pyridine), affording E-3a in 62% yield. However, using 2,6-lutidine
or imidazole as the Lewis base promoter under the standard con-
ditions gave E-3a in 31% yield or 23% yield, respectively (Table 1,
entries 8 and 9). Next, we used DABCO as the catalyst to examine
the solvent effects. We found that THF was the best solvent (Table 1,
entries 4 vs 11e14). Other solvents, such as toluene or DCM had
a negative influence on the yield of 3a (Table 1, entries 11 and 12). In
MeCN and DMF, 3a was only obtained in 33% and 41% yields,
Previously, Kwon and co-workers have reported phosphine-
catalyzed reaction of oximes with allenic esters, providing b0
-
umpolung addition products due to the nucleophilicity of the
oximes8s and we have reported Lewis base (P(4-FC6H4)3) catalyzed
cascade reactions of isatin-derived oximes with allenic esters to
furnish the corresponding nitrones, which could be further con-
verted to bridged cycloadducts via intramolecular [3þ2] cyclization
catalyzed by Lewis acid [Yb(OTf)3] (Scheme 1).12 Therefore, we
attempted to replace allenic esters with multifunctional allenyl
acetates. We initially utilized allenyl acetate (1a) and (E)-1-benzyl-
3-(hydroxyimino)-indolin-2-one (2a) as substrates to investigate
their reaction behavior in THF at room temperature in the presence
of Lewis base. The results are summarized in Table 1. Firstly, we
found that the corresponding product 3a was furnished in poor
chemical yields using phosphorus-containing Lewis bases (PPh3,
PhPMe2, P(4-FC6H4)3) (Table 1, entries 1e3) as catalysts. Consider-
ing the different reactivities between phosphorus-containing and
nitrogen-containing Lewis bases, we investigated the reactions in

Y.-L. Yang et al. / Tetrahedron 69 (2013) 3593e3607
3595
Table 1
Optimization of the reaction conditions
Cl
Cl
HO
N
O
N
O
CO2Et
cat, solvent
r.t., 5 h
CO2Et
O
+
N
AcO
Bn
N
Bn
2a
3a
1a
Entry
Catalyst
Solvent
Yielda (%)
1
2
3
4
5
6
7
8
PPh3
PhPMe2
Tris(4-fluorophenyl)phosphine
DABCO
Pyridine
Et3N
THF
THF
THF
THF
THF
THF
THF
THF
21
31
35
88
21
67
62
31
23
31
51
60
33
41
97
90
DMAP
2,6-Lutidine
Imidazole
DBU
DABCO
DABCO
DABCO
DABCO
DABCO
DABCO
9
THF
THF
10
11
12
13
14
15b
16b,c
Toluene
DCM
MeCN
DMF
THF
THF
a
Isolated yield. Unless otherwise specified, 1a (0.10 mmol), 2a (0.10 mmol), and catalyst (0.02 mmol) were used.
b
To a mixture of 2a (0.10 mmol) and catalyst (0.02 mmol) in THF (1.0 mL) under Ar atmosphere was added the solution of 1a (0.15 mmol in 1.0 mL THF) by syringe pump for
30 min.
c
The catalyst loading was 10 mol %.
Table 2
DABCO catalyzed reactions of allenyl acetates with isatin-derived oximes
R1
HO
R1
N
N
O
O
CO2Et
CO2Et
DABCO (20 mol%)
THF, r.t., 5 h
R2
AcO
O
+
N
N
R3
R3
1
2
R2
3
Entry
R1
R2/R3
Yielda (%)
1
2
3
4
5
6
7
8
3-BrC6H4 (1b)
4-NO2C6H4 (1c)
2-MeOC6H4 (1d)
4-MeC6H4 (1e)
4-CF3C6H4 (1f)
3-MeOC6H4 (1g)
3,4-Cl2C6H3 (1h)
3,4,5-MeO3C6H2 (1i)
2-Naphthyl (1j)
2-Thienyl (1k)
n-Heptyl (1l)
H/Bn (2a)
H/Bn (2a)
H/Bn (2a)
H/Bn (2a)
H/Bn (2a)
H/Bn (2a)
H/Bn (2a)
H/Bn (2a)
H/Bn (2a)
H/Bn (2a)
H/Bn (2a)
H/Bn (2a)
3b (90)
3c (85)
3d (83)
3e (92)
3f (87)
3g (89)
3h (96)
3i (92)
3j (94)
3k (90)
3l (42)
3m (88)
3n (80)
3o (82)
3p (86)
3q (83)
3r (90)
3s (95)
3t (91)
9
10
11
12
13
14
15
16
17
18
19
C6H5 (1m)
C6H5 (1m)
5-Br/Tr (2b)
4-ClC6H4 (1a)
4-ClC6H4 (1a)
3-BrC6H4 (1b)
3-MeOC6H4 (1g)
4-MeC6H4 (1e)
2-Thienyl (1k)
6-Br/allyl (2c)
5-Br/allyl (2d)
5-Me/Bn (2e)
7-Br/allyl (2f)
6-Me/allyl (2g)
H/allyl (2h)
a
Isolated yield. Unless otherwise specified, to a mixture of 2 (0.10 mmol) and DABCO (0.02 mmol) in THF (1.0 mL) under Ar atmosphere was added the solution 1
(0.15 mmol in 1.0 mL THF) by syringe pump for 30 min.

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Y.-L. Yang et al. / Tetrahedron 69 (2013) 3593e3607
Table 3
Optimization of the reaction conditions
Cl
O
N
O
Bn
N
Cl
CO2Et
HO
N
3a
cat, solvent
r.t., 8 h
+
+
O
CO2Et
N
Bn
Cl
AcO
2a
-O
N+
CO2Et
O
N
4a
Bn
Entry
1A/2a
Catalyst
Pyridine
Solvent
2a (M/mol Lꢀ1
)
Yielda (%)
4a
3a
1
2
3
4
5
6
7
8
1.0/1.0
1.5/1.0
1.5/1.0
1.5/1.0
1.5/1.0
1.0/1.0
1.0/1.0
1.0/1.0
1.0/1.0
1.0/1.0
1.0/1.0
1.0/1.0
1.0/1.0
1.0/1.0
1.0/1.5
1.0/1.5
THF
THF
THF
THF
THF
THF
THF
THF
MeCN
Toluene
DMF
DCM
1,4-Dioxane
EtOH
0.10
0.05
0.05
0.05
0.05
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.15
0.15
37
12
d
21
33
55
62
28
43
47
47
45
4
70
20
8
25
d
d
3-Bromopyridine
3,5-Dibromopyridine
4-Methoxypyridine
3,5-Dimethylpyridine
Nicotinonitrile
2-Chloro-5-(trifluo romethyl)pyridine
pyridin-2-ol
3,5-Dimethylpyridine
3,5-dimethylpyridine
3,5-Dimethylpyridine
3,5-Dimethylpyridine
3,5-Dimethylpyridine
3,5-Dimethylpyridine
3,5-Dimethylpyridine
3,5-Dimethylpyridine
d
41
8
d
d
9
14
84
Trace
58
76
Trace
90
85
10
11
12
13
14
15
16b
Toluene
Toluene
a
Isolated yield. The substrates were added in one pot manner. Unless otherwise specified, the catalyst loading was 20 mol %.
The catalyst loading was 10 mol %.
b
respectively (Table 1, entries 13 and 14). Considering that 1a can be
easily converted to (E)- -ethynyl-
-unsaturated ester,10 we de-
if R1 was a n-heptyl group, the desired product 3l was acquired in 42%
yield (Table 2, entry 11). With oximes 2beh bearing different N-
protecting groups and having a bromo, methyl or no substituent at
thearomatic ring, thereactionsproceeded smoothly to give thetarget
products 3net in good yields (80e95%) (Table 2, entries 13e19).
The structure of 3 has been unambiguously determined by X-ray
diffraction of the analogue 3j. The ORTEP drawing is shown in Fig. 2
and its CIF data of 3j are presented in the Supplementary data.13
As aforementioned, byproduct 4a was obtained if pyridine was
used as the catalyst (Table 3, entry 1). Thus, we continued to op-
timize the reaction in order to obtain 4a as a sole product. The
results are summarized in Table 3. Initially, we examined the re-
action outcomes by addition of the substrates in a one portion
manner in the presence of various pyridine derivatives, such as 3-
bromopyridine, 3,5-dibromopyridine, 4-methoxypyridine, 3,5-
dimethylpyridine. We found that 3,5-dimethylpyridine gave 4a in
relatively high yield accompanying with 3a (Table 3, entries 1e5).
When using other pyridine derivatives, such as nicotinonitrile, 2-
chloro-5-(trifluoromethyl)pyridine and pyridin-2-ol as the cata-
lysts, the target product 4a was hardly obtained under the standard
conditions (Table 3, entries 6e8). Hence, we finally chose 3,5-
dimethylpyridine as catalyst to examine the solvent effects. Upon
screening of different solvents (MeCN, toluene, DMF, DCM, 1,4-
dioxane, EtOH), we found the best solvent was toluene, affording
4a in 84% yield along with trace amount of 3a (0.10 M of 2a) (Table
a
a,b
cided to change the order of adding substrates and increase the
employed amount of 1a. To a mixture of 2a (0.10 mmol) and catalyst
(0.02 mmol) in THF (1.0 mL) under argon atmosphere was added
the solution of 1a (0.15 mmol in 1.0 mL of THF) by a syringe pump
for 30 min, and then the resulting mixture was stirred for 4.5 h,
affording 3a in 97% yield (Table 1, entry 15). Using 10 mol % of the
catalyst loading afforded 3a in 90% yield under identical conditions,
suggesting that 20 mol % of catalyst should be used in this reaction
process (Table 1, entry 16). Inorganic bases did not catalyze this
reaction under the standard conditions.
Under these optimized conditions, we next examined the gener-
ality of this reaction using various allenyl acetates (1) and oximes (2).
The results are presented in Table 2. A variety of allenyl acetates 1
having either electron-donating or withdrawing groups as sub-
stituents on the 2-, 3-, 4-position of benzene ring were examined,
affording the corresponding oxime ethers 3 in high yields (83e92%)
(Table 2, entries 1e6). Moreover, 3,4-disubstituted allenyl acetate 1h,
3,4,5-trisubstituted allenyl acetate 1i, and allenyl acetate 1m having
no substituent on the benzene ring also gave the corresponding
products 3h, 3i, and 3min highyields (Table 2, entries 7e8,12). When
R1 was a 2-naphthyl or a 2-thienyl group, the reactions also pro-
ceeded efficiently to furnish the corresponding products 3j and 3k in
94% and 90% yields, respectively (Table 2, entries 9 and 10). However,

Y.-L. Yang et al. / Tetrahedron 69 (2013) 3593e3607
3597
With these optimized conditions in hand, we next investigated
the tolerance of various allenyl acetates 1 and oximes 2. The results
are presented in Table 4. When R2¼H, R3¼Bn or allyl group, we
found that the corresponding products 4 were obtained in high
yields with good stereoselectivities (high ratios of E/Z), regardless
of whether allenyl acetates 1 have electron-donating or electron-
withdrawing group at ortho, meta, para position on the benzene
ring of R1 (Table 4, entries 1e5 and 16e17). Meanwhile, 3,4,5-
trisubstituted allenyl acetate, allenyl acetate having a heterocycle
or a 2-naphthyl group also gave the desired products in high yields
and high ratios of E/Z (Table 4, entries 7e9) except for substrate 1h
in which R1 has a 3,4-disubstituted benzene ring and the desired
product 4g was formed in 79% yield (Table 4, entry 6). However, if
R1 was an aliphatic group (n-heptyl), the reaction only gave trace
amount of 4k (Table 4, entry 10). Moreover, regardless of an
electron-donating or electron-withdrawing group was introduced
at the 5-, 6-, or 7-position on the benzene ring of oximes or
changing the N-protecting groups of oximes, the reactions also
proceeded smoothly to produce the corresponding nitrones 4ler in
good to high yields with good to excellent stereoselectivities (Table
4, entries 11e17).
The structures of the major and minor isomers of 4 have been
also unambiguously determined by X-ray diffraction of analogue
(1E,3E)-4a (major isomer) and (1E,3Z)-4r (minor product). Their
ORTEP drawings are shown in Fig. 3 and Fig. 4, respectively, and the
related CIF data are presented in the Supplementary data.14
Plausible mechanisms for these reactions are outlined in
Scheme 2. Based on the earlier report proposed by Lee,10 we pro-
pose the path a as a traditional reaction model to account for the
formation of product 3. DABCO is added to react with allenyl ace-
tate, producing zwitterionic intermediate A, which was detected in
NMR spectroscopic investigation by Lee and co-workers. Sub-
sequently, deprotonation of pronucleophile forms negative oxygen
ion B, which attacks intermediate A by passing through transition
state C via SN2-type displacement to furnish the corresponding
Fig. 2. ORTEP drawing of 3j.
3, entries 9e14). To our delight, 4a was afforded in 90% yield as the
sole product upon increasing the employed amount of 2a to 0.15 M
(Table 3, entry 15). When the catalyst loading was reduced to
10 mol %, 4a could be still obtained in 85% yield (Table 3, entry 16).
Table 4
3,5-Dimethylpyridine catalyzed reactions of allenyl acetates with isatin-derived oximes
R1
2
-O
HO
3
R1
N+
N
CO2Et
N
1
R2
CO2Et
(20 mol-%)
AcO
R2
O
+
O
toluene, r.t., 8 h
N
N
R3
R3
1 (1.0 equiv)
2 (1.5 equiv)
4
Entry
R1
R2/R3
Yield (%)a ((1E,3E)-4/(1E,3Z)-4)
1
2
3
4
5
6
7
8
3-BrC6H4 (1b)
2-MeOC6H4 (1d)
4-MeC6H4 (1e)
4-CF3C6H4 (1f)
3-MeOC6H4 (1g)
3,4-Cl2C6H3 (1h)
3,4,5-MeO3C6H2 (1i)
2-Naphthyl (1j)
2-Thienyl (1k)
n-Heptyl (1l)
3-BrC6H4 (1b)
2-Naphthyl (1j)
4-ClC6H4 (1a)
4-MeC6H4 (1e)
4-ClC6H4 (1a)
H/Bn (2a)
H/Bn (2a)
H/Bn (2a)
H/Bn (2a)
H/Bn (2a)
H/Bn (2a)
H/Bn (2a)
H/Bn (2a)
4b 89 (6:1)
4c 83 (50:1)
4d 90 (11:1)
4e 92 (13:1)
4f 93 (14:1)
4g 79 (4:1)
4h 92 (>99:1)
4i 96 (25:1)
4j 92 (9:1)
4k n.d.
4l 88 (5:1)
4m 95 (8:1)
4n 82 (7:1)
4o 84 (18:1)
4p 91 (8:1)
4q 94 (5:1)
4r 95 (20:1)
9
H/Bn (2a)
H/Bn (2a)
10
11
12
13
14
15
16
17
5-Me/Bn (2e)
5-Me/Bn (2e)
7-Br/allyl (2f)
7-Br/allyl (2f)
6-Me/allyl (2g)
H/allyl (2h)
H/allyl (2h)
3-BrC6H4 (1b)
3-MeOC6H4 (1g)
a
Isolated yield. The substrates were added in one portion manner.

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Y.-L. Yang et al. / Tetrahedron 69 (2013) 3593e3607
ammonium ions derived from the reactions of amines with elec-
trophile benefits the formation of product. According to Mayr’s
report,16c the reactivity of 3,5-dimethylpyridine should be superior
to that of DABCO in this type of the reaction.
In order to understand the detailed mechanism for the forma-
tion of product 4, we have also theoretically investigated the re-
action pathway b. All calculations have been performed at the
mPW1K/6-31þG(d) level of theory with Gaussian 09 program.17
The relative energies of all intermediates and transitional states
along the suggested path b are shown in Scheme 3 (for details, see
Supplementary data). Initially, the addition of catalyst 3,5-
dimethylpyridine to compound 1 leads to the formation of in-
termediate 6. Then, the oxime is bonded to intermediate 6 to give
a complex 7. The oxime is deprotonated to obtain the intermediate
9 via transition state 8 with an energy barrier of 0.5 kcal/mol. The
nitrogen of oxime attacks the carbon of terminal olefin through
transition state 10 with an energy barrier of 18.4 kcal/mol, affording
the corresponding intermediate 11. The intermediate 11 undergoes
a 1,2-proton transfer by passing transition state 12 with an energy
barrier of 47.3 kcal/mol, giving the intermediate 13. Subsequently,
the catalyst is eliminated through transition state 14, leading to the
product complex 15. Cleavage of this complex to yield the separate
components 4, 3,5-dimethylpyridine, AcOH is endothermic by ap-
proximately 3 kcal/mol.
Fig. 3. ORTEP drawing of (1E,3E)-4a.
3. Conclusion
In summary, we have established novel and interesting re-
actions of allenyl acetates with isatin-derived oximes catalyzed by
different nitrogen-containing Lewis bases, affording the corre-
sponding oxime ethers or nitrones in good to high yields with high
regio- and stereoselectivities. The steric and electronic factors of
this reaction are not obvious but mainly depend on substrate 1. For
example, in Table 2 (entries 13e18) and Table 4 (entries 11e17), the
yield and stereoselectivity of products 3 and 4 are better than those
with withdrawing groups when an electron-donating group was
introduced in substrate 1. The mechanistic insights have been dis-
closed by control experiments and DFT calculations. Further studies
on the mechanistic details of this catalytic system along with the
properties of highly active allenyl acetates are currently underway
in our laboratory.
Fig. 4. ORTEP drawing of (1E,3Z)-4r.
product 3 and to regenerate the DABCO catalyst. During the ex-
periments, we noticed that the yield of product 3a had some re-
lation with the nucleophilicity of catalyst. Thus, we plotted the
correlation line between the yield of 3a and the N (N: nucleophi-
licity parameter) parameters of several catalysts (shown in Fig. 5 or
Fig. S1 in the Supplementary data and the N parameter of 2,6-
Lutidine derived from 4-methylpyridine in DCM).16aeg It demon-
strated that the yield of 3a indeed had a linear correlation
(R2¼0.98) with N parameters of catalysts. Therefore, this observa-
tion was in accordance with Mayr’s findings16c that if the reaction
was controlled by the rate of nucleophilic attack of the organo-
catalyst, the high nucleophilicity and nucleofugicity of DABCO is
superior to that of 3,5-dimethylpyridine.
The formation of product 4 is proposed through path b in
Scheme 2. In path b, the addition of 3,5-dimethylpyridine to allenyl
acetate generates zwitterionic intermediate D, which gives nega-
tive oxygen ion B via deprotonation of pronucleophile. According to
Mayr’s work in 2007,16c 3,5-dimethylpyridine owned lower nucle-
ophilicity, which implied that the ability of nucleofuge was worse
than that of DABCO. Thus the following SN2-type reaction may be
difficult to occur in the reaction catalyzed by 3,5-dimethylpyridine.
Instead of taking place SN2-type reaction, the nitrogen of B attacks
the carbon of terminal olefin in intermediate D, giving the corre-
sponding intermediate E. Subsequently, the intermediate E un-
dergoes the 1,2-proton shift to give intermediate F, which releases
the catalyst 3,5-dimethylpyridine to form the product 4. It has to
point out here that the product 4 is obtained by addition of sub-
strates in a one portion manner (for details, see Supplementary
data), indicating that the high concentration of intermediate
4. Experimental section
4.1. General remarks
1H NMR spectra were recorded on a Bruker AM-300 or AM-400
spectrometer for solution in CDCl3 with tetramethylsilane (TMS) as
internal standard; J-values are in Hertz. Mass spectra were recorded
with a HP-5989 instrument. All of the compounds reported in this
paper gave satisfactory HRMS analytic data. Melting points were
determined on a digital melting point apparatus and temperatures
were uncorrected. Infrared spectra were recorded on a Per-
kineElmer PE-983 spectrometer with absorption in cmꢀ1. THF,
toluene, and Et2O were distilled from sodium (Na) under argon (Ar)
atmosphere. CH3CN, DMF, and dichloromethane were distilled
from CaH2 under argon (Ar) atmosphere. Commercially obtained
reagents were used without further purification. All reactions were
monitored by TLC with Huanghai GF254 silica gel coated plates.
Flash column chromatography was carried out using
300e400 mesh silica gel at increased pressure. According to the
previous literature,10,15 Compounds 1aem were prepared. Among
them, compounds 1a, 1b, 1g, and 1m were known compounds, the
others were new compounds.
Compound 1d. A yellow oil. IR (CH2Cl2):
n 2984, 1967, 1741, 1712,
1603,1493,1464, 1439,1368,1248,1223,1110,1086,1049,1024, 972,

Y.-L. Yang et al. / Tetrahedron 69 (2013) 3593e3607
3599
Scheme 2. Plausible reaction mechanisms.
856 cmꢀ1
;
1H NMR (400 MHz, CDCl3, TMS):
d
7.32e7.25 (2H, m),
4.21e4.14 (2H, m), 2.33 (3H, s), 2.07 (3H, s), 1.23 (3H, t, J¼7.2 Hz);
13C NMR (CDCl3, 100 MHz):
213.2, 169.6, 164.8, 138.1, 135.1, 129.0,
127.3, 102.7, 82.0, 71.5, 61.2, 21.2, 21.0, 14.1; MS (ESI) m/e 297.1
(MþþNa); HRMS (ESI) for C16H18O4 (Mþ): 274.1205, Found:
274.1196.
7.00 (1H, t, J¼2.0 Hz), 6.93 (1H, t, J¼7.2 Hz), 6.86 (1H, d, J¼8.0 Hz),
5.19 (1H, dd, J1¼14.4 Hz, J2¼2.4 Hz), 5.13 (1H, dd, J1¼14.4 Hz,
J2¼2.4 Hz), 4.19 (2H, q, J¼6.8 Hz), 3.83 (3H, s), 2.09 (3H, s), 1.24 (3H,
d
t, J¼7.2 Hz); 13C NMR (CDCl3, 100 MHz):
d 214.1, 169.5, 165.0, 156.5,
129.3,127.4, 126.3, 120.2, 110.5,101.9, 81.4, 66.8, 61.1, 55.5, 21.0, 14.1;
MS (ESI) m/e 313.1 (MþþNa); HRMS (ESI) for C16H18O5 (Mþ):
290.1154, Found: 290.1146.
Compound 1f. A yellow oil. IR (CH2Cl2):
1712, 1621, 1420, 1369, 1324, 1254, 1224, 1124, 1066, 1017, 978,
856 cmꢀ1; 1H NMR (400 MHz, CDCl3, TMS):
n 2987, 1967, 1935, 1746,
d
7.60 (2H, d, J¼8.0 Hz),
Compound 1e. A yellow oil. IR (CH2Cl2):
1711, 1596, 1515, 1446, 1367, 1255, 1224, 1180, 1088, 1018, 972, 852,
789, 749 cmꢀ1 1H NMR (400 MHz, CDCl3, TMS):
7.30 (2H, d,
n
2925, 2853, 1965, 1742,
7.52 (2H, d, J¼8.0 Hz), 6.63 (1H, s), 5.34 (1H, dd, J1¼14.8 Hz,
J2¼1.6 Hz), 5.27 (1H, dd, J1¼14.8 Hz, J2¼1.6 Hz), 4.22e4.16 (2H, m),
2.11 (3H, s), 1.25 (3H, t, J¼7.2 Hz); 13C NMR (CDCl3, 100 MHz):
;
d
J¼8.0 Hz), 7.14 (2H, d, J¼8.0 Hz), 6.55 (1H, t, J¼2.4 Hz), 5.32 (1H, dd,
d
213.5, 169.4, 164.6, 142.2, 130.4 (q, J¼32.2 Hz), 127.5, 125.3 (q,
J1¼14.4 Hz, J2¼2.8 Hz), 5.27 (1H, dd, J1¼14.4 Hz, J2¼2.4 Hz),
J¼3.8 Hz), 121.3 (q, J¼272.4 Hz), 102.2, 82.4, 71.0, 61.5, 20.9, 14.1; 19F

3600
Y.-L. Yang et al. / Tetrahedron 69 (2013) 3593e3607
13C NMR (CDCl3, 100 MHz):
61.2, 33.4, 31.7, 29.2, 29.1, 25.4, 22.6, 21.0, 14.1, 14.0; MS (ESI) m/e
283.2 (MþþH); HRMS (ESI) for C16H26O4 (Mþ): 282.1831, Found:
282.1825.
Reaction procedure for the preparation of product 3 has been
summarized in the Supplementary data and the spectroscopic data
are shown below.
d 213.2, 170.1, 165.2, 101.9, 81.4, 70.1,
90
80
70
60
50
40
30
20
DABCO
Et3N
DMAP
4.1.1. (E)-Ethyl 3-((E)-1-benzyl-2-oxoindolin-3-ylideneaminooxy)-2-
(4-chlorobenzylidene)but-3-enoate 3a. Following the general pro-
cedure, the mixture was purified by column chromatography using
silica gel to give the target product 3a (47 mg, 97% yield). A yellow
R2 = 0.98
solid. Mp for compound 3a¼56e58 ꢁC; IR (CH2Cl2):
n
2925, 2854,
2,6-Lutidine
Pyridine
1712, 1661, 1606, 1490, 1465, 1348, 1306, 1181, 1161, 1092, 1075, 1051,
990, 948, 833 cmꢀ1; 1H NMR (400 MHz, CDCl3, TMS):
d 7.84 (1H, s),
7.74 (1H, d, J¼7.6 Hz), 7.57 (2H, d, J¼8.4 Hz), 7.34e7.25 (8H, m), 6.93
(1H, t, J¼7.6 Hz), 6.72 (1H, d, J¼7.6 Hz), 5.53 (1H, d, J¼2.4 Hz), 4.95
(2H, s), 4.67 (1H, d, J¼2.4 Hz), 4.31 (2H, q, J¼7.2 Hz), 1.31 (3H, t,
12
13
14
15
16
17
18
19
N (Mayr Nuc Parameter)
J¼7.2 Hz); 13C NMR (CDCl3, 100 MHz):
d 166.2, 163.2, 154.4, 146.1,
Fig. 5. Correlation of yield of 3a (%) and N (Mayr Nuc Parameter).
144.1,142.8,136.0,135.1,133.4,132.3,131.6,128.9,128.8,128.7,127.9,
127.4, 126.3, 123.1, 115.4, 109.6, 95.2, 61.5, 43.8, 14.2; MS (ESI) m/e
487.1 (MþþH); HRMS (ESI) for C28H23ClN2O4 (Mþ): 486.1346,
Found: 486.1332.
NMR (376 MHz, CDCl3, CFCl3):
d
ꢀ62.7; MS (ESI) m/e 351.1
(MþþNa); HRMS (ESI) for C16H15F3O4 (Mþ): 328.0922, Found:
328.0914.
Compound 1h. A yellow oil. IR (CH2Cl2):
1430, 1348, 1324, 1136, 1136, 1097, 1077, 1027, 962, 833 cmꢀ1
NMR (400 MHz, CDCl3, TMS):
n
2923, 1712, 1604, 1520,
1H
7.48 (1H, d, J¼2.0 Hz), 7.41 (1H, d,
4.1.2. (E)-Ethyl 3-((E)-1-benzyl-2-oxoindolin-3-ylideneaminooxy)-2-
(3-bromobenzylidene)but-3-enoate 3b. Following the general pro-
cedure, the mixture was purified by column chromatography using
silica gel to give the target product 3b (48 mg, 90% yield). A yellow
;
d
J¼8.0 Hz), 7.26e7.23 (1H, m), 6.52 (1H, t, J¼2.4 Hz), 5.36 (1H, dd,
J1¼14.8 Hz, J2¼2.4 Hz), 5.30 (1H, dd, J1¼14.8 Hz, J2¼2.4 Hz),
4.22e4.16 (2H, m), 2.10 (3H, s), 1.25 (3H, t, J¼7.2 Hz); 13C NMR
solid. Mp for compound 3b¼60e63 ꢁC; IR (CH2Cl2):
n 2925, 2886,
1716, 1606, 1495, 1465, 1379, 1348, 1249, 1184, 1050, 1028, 949,
(CDCl3, 100 MHz):
d
212.4, 169.3, 164.6, 138.5, 132.4, 132.3, 130.3,
844 cmꢀ1; 1H NMR (400 MHz, CDCl3, TMS):
d 7.80 (1H, s), 7.71e7.68
129.1, 126.7, 102.0, 82.5, 70.4, 61.5, 20.9, 14.1; MS (ESI) m/e 351.1
(MþþNa); HRMS (ESI) for C15H14Cl2O4 (Mþ): 328.0269, Found:
328.0262.
(2H, m), 7.59e7.57 (1H, m), 7.38e7.24 (7H, m), 7.15 (1H, t, J¼8.0 Hz),
6.92 (1H, dt, J1¼8.0 Hz, J2¼0.8 Hz), 6.70 (1H, d, J¼8.0 Hz), 5.55 (1H,
d, J¼6.4 Hz), 4.94 (2H, s), 4.70 (1H, d, J¼6.8 Hz), 4.31 (2H, q,
Compound 1i. A yellow oil. IR (CH2Cl2):
1712, 1592, 1506, 1421, 1368, 1333, 1226, 1150, 1125, 1025, 1008,
859 cmꢀ1; 1H NMR (400 MHz, CDCl3, TMS):
6.63 (2H, s), 6.53 (1H,
n
2987, 2940, 1966, 1744,
J¼7.2 Hz), 1.31 (3H, t, J¼7.2 Hz); 13C NMR (CDCl3, 100 MHz):
d 166.0,
163.1, 154.2, 146.0, 144.1, 142.1, 136.0, 135.1, 133.3, 133.1, 132.6, 129.9,
128.8, 128.6, 128.4, 127.8, 127.3, 123.1, 122.4, 115.3, 109.5, 95.7, 61.6,
43.7, 14.2; MS (ESI) m/e 548.1 (MþþNH4); HRMS (ESI) for
C28H23BrN2O4 (Mþ): 530.0841, Found: 530.0831.
d
s), 5.34 (1H, dd, J1¼14.4 Hz, J2¼2.4 Hz), 5.29 (1H, dd, J1¼14.4 Hz,
J2¼2.4 Hz), 4.23e4.17 (2H, m), 3.86 (6H, s), 3.83 (3H, s), 2.11 (3H, s),
1.25 (3H, t, J¼7.2 Hz); 13C NMR (CDCl3, 100 MHz):
d 213.2, 169.5,
164.8,153.0,137.9,133.6,104.4,102.6, 82.1, 71.6, 61.3, 60.7, 56.0, 21.0,
14.1; MS (ESI) m/e 373.1 (MþþNa); HRMS (ESI) for C18H22O7 (Mþ):
350.1366, Found: 350.1360.
4.1.3. (E)-Ethyl 3-((E)-1-benzyl-2-oxoindolin-3-ylideneaminooxy)-2-
(4-nitrobenzylidene)but-3-enoate 3c. Following the general pro-
cedure, the mixture was purified by column chromatography using
silica gel to give the target product 3c (42 mg, 85% yield). A yellow
Compound 1j. A yellow oil. IR (CH2Cl2):
1708, 1348, 1366, 1220, 1169, 1084, 1023, 980, 952, 857 cmꢀ1
NMR (400 MHz, CDCl3, TMS): 7.88 (1H, s), 7.85e7.81 (3H, m), 7.50
n
3059, 2983, 1966, 1741,
;
1H
solid. Mp for compound 3c¼70e72 ꢁC; IR (CH2Cl2):
n 2925, 2862,
d
1716, 1605, 1518, 1495, 1465, 1343, 1301, 1248, 1181, 1112, 1049, 947,
(1H, dd, J1¼8.4 Hz, J2¼1.6 Hz), 7.48e7.46 (2H, m), 6.77 (1H, t,
J¼2.0 Hz), 5.33 (1H, dd, J1¼14.8 Hz, J2¼2.4 Hz), 5.27 (1H, dd,
J1¼14.8 Hz, J2¼2.4 Hz), 4.20e4.14 (2H, m), 2.12 (3H, s), 1.23 (3H, t,
897, 850 cmꢀ1 1H NMR (400 MHz, CDCl3, TMS):
; d 8.15 (2H, d,
J¼8.8 Hz), 7.91 (1H, s), 7.75 (2H, d, J¼8.4 Hz), 7.72 (1H, dd, J1¼7.6 Hz,
J2¼0.8 Hz), 7.33e7.26 (6H, m), 6.93 (1H, dt, J1¼7.6 Hz, J2¼0.8 Hz), 6.72
(1H, d, J¼8.0 Hz), 5.52 (1H, d, J¼6.4 Hz), 4.95 (2H, s), 4.69 (1H, d,
J¼2.4 Hz), 4.33 (2H, q, J¼7.2 Hz), 1.32 (3H, t, J¼7.2 Hz); 13C NMR
J¼7.2 Hz); 13C NMR (CDCl3, 100 MHz):
d 213.4, 169.6, 164.8, 135.4,
133.2, 133.0, 128.13, 128.10, 127.6, 126.5, 126.23, 126.16, 124.9, 102.6,
82.2, 71.7, 61.3, 21.0, 14.1; MS (ESI) m/e 333.1 (MþþNa); HRMS (ESI)
for C19H18O4 (Mþ): 310.1205, Found: 310.1199.
(CDCl3, 100 MHz):
d 165.5, 163.0, 154.0, 147.9, 146.2, 144.3, 141.0,
140.4, 135.0, 133.6, 130.8, 129.7, 128.9, 128.5, 127.9, 127.4, 123.6, 123.1,
115.3, 109.7, 96.4, 61.9, 43.8, 14.2; MS (ESI) m/e 515.2 (MþþNH4);
HRMS (ESI) for C28H23N3O6 (Mþ): 497.1587, Found: 497.1575.
Compound 1k. A yellow oil. IR (CH2Cl2):
1711, 1445, 1367, 1258, 1222, 1093, 1022, 967, 856 cmꢀ1
(400 MHz, CDCl3, TMS):
n
2961, 2928, 1967, 1741,
;
1H NMR
d
7.27 (1H, d, J¼5.2 Hz), 7.11 (1H, d,
J¼2.8 Hz), 6.96 (1H, dd, J1¼4.8, Hz, J2¼3.6 Hz), 6.85 (1H, d, J¼1.6 Hz),
5.38 (2H, d, J¼2.0 Hz), 4.24e4.17 (2H, m), 2.09 (3H, s), 1.25 (3H, t,
4.1.4. (E)-Ethyl 3-((E)-1-benzyl-2-oxoindolin-3-ylideneaminooxy)-2-
(2-methoxybenzylidene)but-3-enoate 3d. Following the general
procedure, the mixture was purified by column chromatography
using silica gel to give the target product 3d (40 mg, 83% yield). A
J¼7.2 Hz); 13C NMR (CDCl3, 100 MHz):
d 212.9, 169.4, 164.5, 141.1,
126.7, 126.5, 125.9, 102.6, 82.7, 67.2, 61.4, 20.9, 14.1; MS (ESI) m/e
289.0 (MþþNa); HRMS (ESI) for C13H14O4S (Mþ): 266.0613, Found:
266.0606.
yellow solid. Mp for compound 3d¼59e61 ꢁC; IR (CH2Cl2):
n 2925,
2853, 1712, 1605, 1485, 1464, 1379, 1347, 1241, 1210, 1181, 1114, 1075,
Compound 1l. A yellow oil. IR (CH2Cl2):
1715, 1465, 1368, 1230, 1021, 961, 855 cmꢀ1
CDCl3, TMS):
5.58e5.55 (1H, m), 5.30 (2H, d, J¼1.6 Hz), 4.21 (2H, q,
J¼7.2 Hz), 2.05 (3H, s), 1.28 (15H, t, J¼7.2 Hz), 0.88 (3H, t, J¼7.2 Hz);
n
2927, 2857, 1971, 1743,
;
1053, 991, 950, 845 cmꢀ1 1H NMR (400 MHz, CDCl3, TMS):
; d 8.22
1H NMR (400 MHz,
(1H, s), 7.77 (1H, dd, J1¼7.6 Hz, J2¼2.8 Hz), 7.63 (1H, dd, J1¼7.6 Hz,
J2¼1.2 Hz), 7.34e7.22 (7H, m), 6.92 (1H, dt, J1¼7.6 Hz, J2¼0.8 Hz),
6.85e6.82 (2H, m), 6.70 (1H, d, J¼8.0 Hz), 5.47 (1H, d, J¼6.4 Hz),
d

HOAc
H
O
OEt
H
N
O
N
HOAc
H
O
N
O
N
OAc O
Bn
12
HOAc
+
HOAc
OAc
H
OEt
OEt
40.5
H
O
O
N
O
1
H
N
N
O
O
N
OEt
OEt
+
5
+
OAc
H
O
N
H
O
H
N
Bn
O
N
Bn
N
6
O
N
10
N
OEt
5
O
-0.2
OEt
6.0
8
N
0.0
O
Bn 14
N
N
-6.8
O
-6.0
-17.6
HOAc
-18.1
-13.6
Bn
4
-18.6
H
O
HOAc
-25.7
-22.7
OEt
O
OH
N
N
N
HOAc
H
O
N
HOAc
H
OAc
O
O
O
N
OEt
N
Bn
H
O
Bn
O
N
H
O
N
O
N
OEt
O
N
OEt
OEt
N
Bn
11
H
O
N
O
N
7
9
N
13
O
Bn
N
15
Bn
Gas-phase enthalpy profile( H298 (kcal/mol)). Calculated at mPW 1K/6-31+G(d) level.
Scheme 3. The Reaction Energy Profile of Path b.

3602
Y.-L. Yang et al. / Tetrahedron 69 (2013) 3593e3607
4.94 (2H, s), 4.64 (1H, d, J¼6.4 Hz), 4.35 (2H, q, J¼7.2 Hz), 3.87 (3H,
4.31 (2H, q, J¼7.2 Hz), 1.31 (3H, t, J¼7.2 Hz); 13C NMR (CDCl3,
s), 1.30 (3H, t, J¼7.2 Hz); 13C NMR (CDCl3, 100 MHz):
d
166.5, 163.3,
100 MHz): d 165.8, 163.1, 154.0, 146.1, 144.2, 141.1, 135.1, 133.9, 133.8,
158.0, 155.2, 145.7, 144.0, 139.6, 135.2, 133.1, 131.2, 130.2, 128.8,
128.7,127.8,127.3, 125.8, 123.2, 123.1,120.4, 115.4,110.4,109.4, 107.9,
94.9, 61.2, 55.5, 43.6, 14.1; MS (ESI) m/e 500.2 (MþþNH4); HRMS
(ESI) for C29H26N2O5 (Mþ): 482.1842, Found: 482.1833.
133.4, 132.6, 132.0, 130.4, 129.0, 128.8, 128.5, 127.8, 127.7, 127.3,
123.1, 115.3, 109.6, 96.0, 61.7, 43.7, 14.2; MS (ESI) m/e 538.1
(MþþNH4); HRMS (ESI) for C28H22Cl2N2O4 (Mþ): 520.0957, Found:
520.0944.
4.1.5. (E)-Ethyl 3-((E)-1-benzyl-2-oxoindolin-3-ylideneaminooxy)-2-
(4-methylbenzylidene)but-3-enoate 3e. Following the general pro-
cedure, the mixture was purified by column chromatography using
silica gel to give the target product 3e (43 mg, 92% yield). A yellow
4.1.9. (E)-Ethyl 3-((E)-1-benzyl-2-oxoindolin-3-ylideneaminooxy)-2-
(3,4,5-trimethoxybenzylidene)but-3-enoate 3i. Following the gen-
eral procedure, the mixture was purified by column chromatogra-
phy using silica gel to give the target product 3i (50 mg, 92% yield).
solid. Mp for compound 3e¼66e68 ꢁC; IR (CH2Cl2):
n
2983, 2924,1711,
A yellow solid. Mp for compound 3i¼62e64 ꢁC; IR (CH2Cl2):
n 2937,
1660, 1605, 1496, 1465, 1348, 1293, 1199, 1179, 1075, 1051, 1014, 948,
2837, 1727, 1659, 1606, 1578, 1505, 1465, 1348, 1246, 1184, 1126,
845 cmꢀ1; 1H NMR (400 MHz, CDCl3, TMS):
d
7.88 (1H, s), 7.77e7.75
1075, 1053, 949, 842 cmꢀ1; 1H NMR (400 MHz, CDCl3, TMS):
d 7.83
(1H, m), 7.56 (2H, d, J¼8.0 Hz), 7.33e7.23 (6H, m), 7.12 (2H, d, J¼8.0 Hz),
6.91 (1H, dt, J1¼7.6 Hz, J2¼0.8 Hz), 6.70 (1H, d, J¼8.0 Hz), 5.53 (1H, d,
J¼2.4 Hz), 4.95 (2H, s), 4.70 (1H, d, J¼2.4 Hz), 4.30 (2H, q, J¼6.8 Hz),
(1H, s), 7.74 (1H, d, J¼7.6 Hz), 7.33e7.23 (6H, m), 7.00 (2H, s), 6.91
(1H, t, J¼7.6 Hz), 6.70 (1H, d, J¼8.0 Hz), 5.59 (1H, d, J¼2.4 Hz), 4.94
(2H, s), 4.76 (1H, d, J¼2.4 Hz), 4.33 (2H, q, J¼7.2 Hz), 3.80 (6H, s),
3.77 (3H, s), 1.33 (3H, t, J¼7.2 Hz); 13C NMR (CDCl3, 100 MHz):
2.29 (3H, s), 1.30 (3H, t, J¼7.2 Hz); 13C NMR (CDCl3, 100 MHz):
d 166.6,
163.3, 154.8, 145.9, 144.4, 144.0, 140.6, 135.1, 133.1, 130.9, 130.6, 129.2,
128.8, 128.7, 127.8, 127.3, 124.6, 123.1, 115.5, 109.4, 94.5, 61.3, 43.7, 21.4,
14.2; MS (ESI) m/e 484.2 (MþþNH4); HRMS (ESI) for C29H26N2O4 (Mþ):
466.1893, Found: 466.1880.
d 166.3, 163.0, 154.9, 152.8, 146.1, 144.1, 144.0, 139.7, 135.0, 133.3,
129.0, 128.8, 128.6, 127.8, 127.2, 124.6, 123.0, 115.3, 109.5, 107.9, 95.3,
61.3, 60.7, 56.1, 43.7, 14.2; MS (ESI) m/e 560.2 (MþþNH4); HRMS
(ESI) for C31H30N2O7 (Mþ): 542.2053, Found: 542.2041.
4.1.6. (E)-Ethyl 3-((E)-1-benzyl-2-oxoindolin-3-ylideneaminooxy)-2-
(4-(trifluoromethyl)benzylidene)but-3-enoate 3f. Following the gen-
eral procedure, the mixture was purified by column chromatography
using silica gel to give the target product 3f (45 mg, 87% yield). Ayellow
4.1.10. (E)-Ethyl 3-((E)-1-benzyl-2-oxoindolin-3-ylideneaminooxy)-
2-(naphthalen-2-ylmethylene)but-3-enoate 3j. Following the gen-
eral procedure, the mixture was purified by column chromatogra-
phy using silica gel to give the target product 3j (47 mg, 94% yield).
solid. Mp for compound 3f¼55e57 ꢁC; IR (CH2Cl2):
n
2927, 2858,1723,
A yellow solid. Mp for compound 3j¼135e138 ꢁC; IR (CH2Cl2):
n
1607, 1466, 1349, 1323, 1253, 1168, 1125, 1092, 1067, 1016, 950,
2979, 2931, 1727, 1660, 1607, 1496, 1466, 1379, 1349, 1240, 1206,
844 cmꢀ1; 1H NMR (400 MHz, CDCl3, TMS):
d
7.89 (1H, s), 7.70 (3H, dd,
1126, 1075, 949, 858 cmꢀ1; 1H NMR (400 MHz, CDCl3, TMS):
d 8.07
J1¼7.6 Hz, J2¼2.4 Hz), 7.54 (2H, d, J¼8.4 Hz), 7.33e7.23 (6H, m), 6.90
(1H, t, J¼8.0 Hz), 6.70 (1H, d, J¼8.0 Hz), 5.50 (1H, d, J¼6.0 Hz), 4.93 (2H,
s), 4.65 (1H, d, J¼6.8 Hz), 4.31 (2H, q, J¼6.8 Hz), 1.30 (3H, t, J¼7.2 Hz);
(1H, s), 8.04 (1H, s), 7.84e7.80 (2H, m), 7.74e7.71 (3H, m), 7.47e7.44
(2H, m), 7.32e7.25 (2H, m), 7.19 (1H, dt, J1¼7.6 Hz, J2¼1.2 Hz), 6.80
(1H, t, J¼8.0 Hz), 6.66 (1H, d, J¼8.0 Hz), 5.58 (1H, d, J¼2.4 Hz), 4.93
(2H, s), 4.72 (1H, d, J¼2.4 Hz), 4.33 (2H, q, J¼7.2 Hz), 1.33 (3H, t,
13C NMR (CDCl3, 100 MHz):
d 165.9, 163.1, 154.2, 146.1, 144.1, 142.2,
137.4, 135.1, 133.4, 131.2 (q, JCeF¼32.4 Hz), 130.3, 128.8, 128.7, 128.6,
128.3, 127.8, 127.3, 125.3 (q, JCeF¼3.7 Hz), 123.7 (q, JCeF¼270.7 Hz),
123.1, 115.3, 109.6, 95.7, 61.7, 43.7, 14.2; 19F NMR (376 MHz, CDCl3,
J¼7.2 Hz); 13C NMR (CDCl3, 100 MHz):
d 166.5, 163.2, 154.8, 146.0,
144.3, 144.0, 135.1, 133.8, 133.1, 132.9, 131.8, 131.5, 128.8, 128.6,
128.58, 128.0, 127.8, 127.6, 127.3, 126.4, 126.3, 125.8, 123.0, 115.4,
109.4, 95.3, 61.4, 43.7, 14.3; MS (ESI) m/e 520.2 (MþþNH4); HRMS
(ESI) for C32H26N2O4 (Mþ): 502.1893, Found: 502.1880.
CFCl3):
d
ꢀ63.0; MS (ESI) m/e 538.2 (MþþNH4); HRMS (ESI) for
C29H23F3N2O4 (Mþ): 520.1610, Found: 520.1597.
4.1.7. (E)-Ethyl 3-((E)-1-benzyl-2-oxoindolin-3-ylideneaminooxy)-2-
(3-methoxybenzylidene)but-3-enoate 3g. Following the general
procedure, the mixture was purified by column chromatography
using silica gel to give the target product 3g (43 mg, 89% yield). A
4.1.11. (E)-Ethyl 3-((E)-1-benzyl-2-oxoindolin-3-ylideneaminooxy)-
2-(thiophen-2-ylmethylene)but-3-enoate 3k. Following the general
procedure, the mixture was purified by column chromatography
using silica gel to give the target product 3k (41 mg, 90% yield). A
yellow solid. Mp for compound 3g¼53e55 ꢁC; IR (CH2Cl2):
n
2980,
yellow solid. Mp for compound 3k¼124e126 ꢁC; IR (CH2Cl2):
n
2935, 2850, 1713, 1605, 1465, 1379, 1348, 1294, 1233, 1161, 1184,
2924, 2854, 1725, 1705, 1658, 1604, 1495, 1465, 1379, 1349, 1250,
1075, 1050, 948, 848 cmꢀ1; 1H NMR (400 MHz, CDCl3, TMS):
d
7.88
1021, 1178, 1075, 1047, 948, 857 cmꢀ1
TMS):
;
1H NMR (400 MHz, CDCl3,
8.07 (1H, s), 7.85 (1H, d, J¼7.2 Hz), 7.44e7.43 (2H, m),
(1H, s), 7.76 (1H, d, J¼8.0 Hz), 7.34e7.21 (9H, m), 6.92 (1H, t,
J¼8.0 Hz), 6.85e6.82 (1H, m), 6.70 (1H, d, J¼8.0 Hz), 5.54 (1H, d,
J¼2.0 Hz), 4.94 (2H, s), 4.69 (1H, d, J¼2.8 Hz), 4.31 (2H, q, J¼7.2 Hz),
3.74 (3H, s), 1.31 (3H, t, J¼7.2 Hz); 13C NMR (CDCl3, 100 MHz):
d
7.34e7.24 (6H, m), 7.03 (1H, t, J¼4.4 Hz), 6.94 (1H, t, J¼8.0 Hz), 6.70
(1H, d, J¼7.6 Hz), 5.68 (1H, d, J¼2.4 Hz), 4.95 (2H, s), 4.85 (1H, d,
J¼2.4 Hz), 4.30 (2H, q, J¼7.2 Hz), 1.29 (3H, t, J¼7.2 Hz); 13C NMR
d
166.3, 163.2, 159.3, 154.7, 146.0, 144.2, 144.0, 135.1, 135.0, 133.2,
(CDCl3, 100 MHz): d 166.3, 163.2, 154.1, 145.9, 144.1, 137.1, 135.1,
129.4, 128.8, 128.7, 127.8, 127.3, 125.9, 123.2, 123.1, 116.4, 115.4, 114.7,
109.5, 95.1, 61.4, 55.2, 43.7, 14.2; MS (ESI) m/e 500.2 (MþþNH4);
HRMS (ESI) for C29H26N2O5 (Mþ): 482.1842, Found: 482.1831.
134.7, 133.2, 131.7, 128.8, 127.7, 127.3, 127.1, 123.1, 122.0, 115.5, 109.5,
95.9, 61.3, 43.7, 14.3; MS (ESI) m/e 476.2 (MþþNH4); HRMS (ESI) for
C26H22N2O4S (Mþ): 458.1300, Found: 458.1288.
4.1.8. (E)-Ethyl 3-((E)-1-benzyl-2-oxoindolin-3-ylideneaminooxy)-2-
(3,4-dichlorobenzylidene)but-3-enoate 3h. Following the general
procedure, the mixture was purified by column chromatography
using silica gel to give the target product 3h (50 mg, 96% yield). A
4.1.12. (E)-Ethyl 2-(1-((E)-1-benzyl-2-oxoindolin-3-ylideneaminooxy)
vinyl)dec-2-enoate 3l. Following the general procedure, the mixture
was purified by column chromatography using silica gel to give the
target product 3l (20 mg, 42% yield). A yellow oil. IR (CH2Cl2):
2854, 1722, 1607, 1466, 1379, 1349, 1250, 1217, 1182, 1051, 952,
750 cmꢀ1; 1H NMR (400 MHz, CDCl3, TMS):
n 2925,
yellow solid. Mp for 3h¼57e59 ꢁC; IR (CH2Cl2):
n 2928, 1724, 1655,
1607, 1496, 1466, 1378, 1348, 1248, 1184, 1157, 1092, 1075, 1029, 949,
d
7.92 (1H, d, J¼7.2 Hz),
844 cmꢀ1; 1H NMR (400 MHz, CDCl3, TMS):
d
7.77 (1H, s), 7.70 (1H,
7.33e7.26 (6H, m), 7.16 (1H, t, J¼7.6 Hz), 7.00 (1H, dt, J1¼7.6 Hz,
J2¼0.8 Hz), 6.72 (1H, d, J¼7.6 Hz), 5.50 (1H, d, J¼2.0 Hz), 4.95 (2H, s),
4.53 (1H, d, J¼2.0 Hz), 4.23 (2H, q, J¼7.2 Hz), 2.39 (2H, dd, J1¼15.2 Hz,
dd, J1¼7.6 Hz, J2¼1.2 Hz), 7.65 (1H, d, J¼2.0 Hz), 7.50e7.48 (1H, m),
7.36e7.25 (7H, m), 6.92 (1H, dt, J1¼7.6 Hz, J2¼1.2 Hz), 6.71 (1H, d,
J¼8.0 Hz), 5.55 (1H, d, J¼2.8 Hz), 4.95 (2H, s), 4.71 (1H, d, J¼2.4 Hz),
J2¼7.2 Hz), 1.48 (2H, m), 1.34e1.23 (11H, m), 0.88e0.81 (3H, m); 13
C

Y.-L. Yang et al. / Tetrahedron 69 (2013) 3593e3607
3603
NMR (CDCl3,100 MHz):
d
165.9, 163.5, 154.2, 150.4, 145.5, 144.1, 135.2,
121.7, 118.2, 116.9. 102.8, 95.8, 61.5, 43.1, 14.2; MS (ESI) m/e 532.1
(MþþNH4); HRMS (ESI) for C24H20N2O4BrCl (Mþ): 514.0295, Found:
514.0283.
133.2, 128.8, 128.7, 128.1, 127.8, 127.4, 123.2, 115.6, 109.6, 94.7, 61.0,
43.7, 31.7, 29.9, 29.3, 29.0, 28.6, 22.6, 14.2, 14.0; MS (ESI) m/e 492.3
(MþþNH4); HRMS (ESI) for C29H34N2O4 (Mþ): 474.2519, Found:
474.2510.
4.1.17. (E)-Ethyl 3-((E)-1-benzyl-5-methyl-2-oxoindolin-3-ylideneam-
inooxy)-2-(3-bromobenzylidene)but-3-enoate 3q. Following the gen-
eral procedure, the mixture was purified by column chromatography
using silica gel to give the target product 3q (45 mg, 83% yield). A
4.1.13. (E)-Ethyl 3-((E)-1-benzyl-2-oxoindolin-3-ylideneaminooxy)-
2-benzylidenebut-3-enoate 3m. Following the general procedure,
the mixture was purified by column chromatography using silica
gel to give the target product 3m (40 mg, 88% yield). A yellow solid.
yellow solid. Mp for compound 3q¼60e63 ꢁC; IR (CH2Cl2):
n 2924,
1716, 1661, 1614, 1593, 1481, 1454, 1339, 1250, 1187, 1154, 1093, 1074,
Mp for compound 3m¼68e71 ꢁC; IR (CH2Cl2):
n
2925, 2853, 1716,
1050, 954, 907, 855 cmꢀ1; 1H NMR (400 MHz, CDCl3, TMS):
d 7.80 (1H,
1607, 1495, 1466, 1378, 1349, 1254, 1183, 1077, 1051, 1029, 951,
s), 7.70 (1H, s), 7.59 (1H, d, J¼8.0 Hz), 7.45 (1H, s), 7.36e7.26 (6H, m),
7.15 (1H, t, J¼8.0 Hz), 7.05 (1H, dd, J1¼8.0 Hz, J2¼0.8 Hz), 6.57 (1H, d,
J¼8.4 Hz), 5.57 (1H, d, J¼2.4 Hz), 4.92 (2H, s), 4.72 (1H, d, J¼2.4 Hz),
4.32 (2H, q, J¼7.6 Hz), 2.18 (3H, s), 1.32 (3H, t, J¼7.2 Hz); 13C NMR
843 cmꢀ1; 1H NMR (400 MHz, CDCl3, TMS):
d 7.91 (1H, s), 7.75 (1H,
dd, J1¼7.6 Hz, J2¼0.8 Hz), 7.66e7.64 (2H, m), 7.33e7.23 (9H, m), 6.91
(1H, dt, J1¼7.6 Hz, J2¼1.2 Hz), 6.70 (1H, d, J¼8.0 Hz), 5.53 (1H, d,
J¼2.4 Hz), 4.95 (2H, s), 4.67 (1H, d, J¼2.0 Hz), 4.31 (2H, q, J¼7.2 Hz),
(CDCl3, 100 MHz): d 166.0, 163.2, 154.1, 146.2, 141.9, 141.8, 136.0, 135.2,
1.31 (3H, t, J¼7.2 Hz); 13C NMR (CDCl3, 100 MHz):
d
166.4, 163.3,
133.6, 133.1, 132.6, 132.5, 129.9, 129.1, 128.8, 128.4, 127.7, 127.3, 122.3,
115.2, 109.3, 95.8, 61.6, 43.7, 20.9, 14.2; MS (ESI) m/e 562.1 (MþþNH4);
HRMS (ESI) for C29H25BrN2O4 (Mþ): 544.0998, Found: 544.0998.
154.6, 146.0, 144.3, 144.1, 135.2, 133.8, 133.2, 130.4, 130.0, 128.8,
128.7, 128.5, 127.8, 127.4, 125.8, 123.1, 115.5, 109.5, 94.7, 61.4, 43.7,
14.2; MS (ESI) m/e 470.2 (MþþNH4); HRMS (ESI) for C28H24N2O4
(Mþ): 452.1736, Found: 452.1723.
4.1.18. (E)-Ethyl 3-((E)-1-allyl-7-bromo-2-oxoindolin-3-ylidene-
aminooxy)-2-(3-methoxybenzylidene)but-3-enoate 3r. Following the
general procedure, the mixture was purified by column chromatog-
raphy using silica gel to give the target product 3r (46 mg, 90% yield).
4.1.14. (E)-Ethyl 2-benzylidene-3-((E)-2-oxo-1-tritylindolin-3-ylide-
neaminooxy)but-3-enoate 3n. Following the general procedure, the
mixture was purified by column chromatography using silica gel to
give the target product 3n (55 mg, 80% yield). A yellow solid. Mp for
A yellow oil; IR (CH2Cl2):
1366,1336,1260,1234,1172,1098,1050,1017, 955, 847 cmꢀ1; 1H NMR
(400 MHz, CDCl3, TMS):
n 2961, 2928, 1735, 1713, 1598, 1466, 1441,
compound 3n¼51e54 ꢁC; IR (CH2Cl2):
n
2923, 2853, 1732,1596,1491,
d
7.88 (1H, s), 7.78 (1H, d, J¼7.6 Hz), 7.46 (1H,
1448,1366,1261,1188,1125,1079,1050,1013, 952, 812 cmꢀ1; 1H NMR
d, J¼7.6 Hz), 7.27e7.18 (3H, m), 6.85e6.79 (2H, m), 6.00e5.94 (1H, m),
5.54 (1H, d, J¼2.4 Hz), 5.22e5.14 (2H, m), 4.82 (2H, t, J¼2.4 Hz), 4.73
(1H, d, J¼2.4 Hz), 4.31 (2H, q, J¼7.2 Hz), 3.74 (3H, s), 1.31 (3H, t,
(400 MHz, CDCl3, TMS):
d
7.89 (1H, s), 7.82 (1H, d, J¼2.0 Hz), 7.60 (1H,
d, J¼6.8 Hz), 7.45e7.41 (6H, m), 7.31e7.21 (12H, m), 7.06 (1H, dd,
J1¼8.8 Hz, J2¼2.0 Hz), 6.14 (1H, d, J¼8.8 Hz), 5.47 (1H, d, J¼2.0 Hz),
4.66 (1H, d, J¼2.0 Hz), 4.33 (2H, q, J¼7.2 Hz),1.32 (3H, t, J¼7.2 Hz); 13C
J¼7.2 Hz); 13C NMR (CDCl3, 100 MHz):
d 166.2, 163.3, 159.3, 154.6,
144.4, 144.3, 141.4, 138.8, 134.9, 132.3, 129.4, 127.8, 125.7, 124.2. 123.1,
118.1, 116.7, 116.4, 114.7, 102.6, 95.7, 61.4, 55.2, 43.0,14.2; MS (ESI) m/e
528.1 (MþþNH4); HRMS (ESI) for C25H23N2O5Br (Mþ): 510.0790,
Found: 510.0781.
NMR (CDCl3,100 MHz): d 166.3,163.2,154.6,144.8,144.3,143.8,141.2,
134.2, 133.8, 130.4, 129.9, 129.2, 128.4, 128.3, 127.8, 127.2, 125.6, 117.6,
117.5, 115.5, 95.4, 75.1, 61.5, 14.3; MS (ESI) m/e 700.2 (MþþNH4);
HRMS (ESI) for C40H31BrN2O4 (Mþ): 682.1467, Found: 682.1464.
4.1.19. (E)-Ethyl 3-((E)-1-allyl-6-methyl-2-oxoindolin-3-ylideneami-
nooxy)-2-(3-methylbenzylidene)but-3-enoate 3s. Following the gen-
eral procedure, the mixture was purified by column chromatography
using silica gel to give the target product 3s (41 mg, 95% yield). A
4.1.15. (E)-Ethyl 3-((E)-1-allyl-6-bromo-2-oxoindolin-3-ylidenea-
minooxy)-2-(4-chlorobenzylidene)but-3-enoate 3o. Following the
general procedure, the mixture was purified by column chromatog-
raphy using silica gel to give the target product 3o (38 mg, 82% yield).
yellow solid. Mp for compound 3s¼83e85 ꢁC; IR (CH2Cl2):
n 2961,
A yellow solid. Mp for compound 3o¼110e113 ꢁC; IR (CH2Cl2):
n
2926,
2923, 2855, 1731, 1614, 1482, 1443, 1366, 1342, 1258, 1181, 1093, 1053,
2850, 1721, 1602, 1486, 1429, 1367, 1336, 1262, 1185, 1090, 1061, 1013,
1017, 955, 799 cmꢀ1; 1H NMR (400 MHz, CDCl3, TMS):
d 7.88 (1H, s),
1
929, 837 cmꢀ1; H NMR (400 MHz, CDCl3, TMS):
d
7.83 (1H, s), 7.56
7.56 (2H, d, J¼8.0 Hz), 7.54 (1H, s), 7.14e7.10 (3H, m), 6.69 (1H, d,
J¼8.0 Hz), 5.86e5.78 (1H, s), 5.52 (1H, d, J¼2.4 Hz), 5.27e5.22 (2H, m),
4.67 (1H, d, J¼2.4 Hz), 4.36e4.35 (2H, m), 4.31 (2H, q, J¼7.2 Hz), 2.29
(3H, s), 2.19 (3H, s), 1.31 (3H, t, J¼7.2 Hz); 13C NMR (CDCl3, 100 MHz):
(3H, t, J¼8.8 Hz), 7.28 (2H, d, J¼8.4 Hz), 7.10 (1H, dd, J1¼8.0 Hz,
J2¼1.6 Hz), 6.97 (1H, d, J¼1.2 Hz), 5.86e5.79 (1H, m), 5.50 (1H, d,
J¼2.4 Hz), 5.30 (1H, s), 5.26 (1H, d, J¼9.2 Hz), 4.68 (1H, d, J¼2.4 Hz),
4.36 (2H, d, J¼5.2 Hz), 4.31 (2H, q, J¼7.2 Hz), 1.31 (3H, t, J¼7.2 Hz); 13C
d
166.6, 162.9, 154.8, 146.1, 144.2, 141.9, 140.5, 133.5, 132.5, 131.0, 130.9,
NMR (CDCl3, 100 MHz):
d
166.1, 162.6, 154.4, 145.2, 142.8, 136.1, 132.2,
130.6, 129.2,129.15, 124.6, 117.8, 115.3, 109.1, 94.5, 61.2, 42.2, 21.4, 20.9,
14.2; MS (ESI) m/e 448.2 (MþþNH4); HRMS (ESI) for C26H26N2O4
(Mþ): 430.1893, Found: 430.1899.
131.6, 130.3, 129.5, 128.8, 128.7, 127.8, 126.2, 126.1, 118.4, 114.0, 113.0,
95.6, 61.5, 42.4, 14.2; MS (ESI) m/e 532.1 (MþþNH4); HRMS (ESI) for
C24H20N2O4BrCl (Mþ): 514.0295, Found: 514.0280.
4.1.20. (E)-Ethyl 3-((E)-1-allyl-2-oxoindolin-3-ylideneaminooxy)-2-
(thiophen-2-ylmethylene)but-3-enoate 3t. Following the general
procedure, the mixture was purified by column chromatography
using silica gel to give the target product 3t (37 mg, 91% yield). A
4.1.16. (E)-Ethyl 3-((E)-1-allyl-5-bromo-2-oxoindolin-3-ylidenea-
minooxy)-2-(4-chlorobenzylidene)but-3-enoate 3p. Following the
general procedure, the mixture was purified by column chromatog-
raphy using silica gel to give the target product 3p (40 mg, 86% yield). A
yellow solid. Mp for compound 3t¼153e154 ꢁC; IR (CH2Cl2):
n 2981,
yellow solid. Mp for compound 3p¼86e88 ꢁC; IR (CH2Cl2):
n
2925,
2925, 1727, 1704, 1604, 1465, 1420, 1348, 1250, 1199, 1179, 1046, 988,
2854, 1724, 1606, 1489, 1463, 1449, 1335, 1259, 1171, 1090, 1041, 954,
947, 856 cmꢀ1; 1H NMR (400 MHz, CDCl3, TMS):
d 8.07 (1H, s), 7.85
799 cmꢀ1; 1H NMR (400 MHz, CDCl3, TMS):
d
7.84 (1H, s), 7.78 (1H, dd,
(1H, dd, J1¼7.6 Hz, J2¼0.4 Hz), 7.44e7.43 (2H, m), 7.34 (1H, dt,
J1¼8.0 Hz, J2¼1.2 Hz), 7.03 (1H, t, J¼8.0 Hz), 6.97 (1H, dt, J1¼7.6 Hz,
J2¼0.8 Hz), 6.81 (1H, d, J¼7.6 Hz), 5.87e5.80 (1H, m), 5.66 (1H, d,
J¼2.4 Hz), 5.29e5.23 (2H, m), 4.83 (1H, d, J¼2.4 Hz), 4.39e4.37 (2H,
m), 4.29 (2H, d, J¼7.2 Hz), 1.29 (3H, t, J¼7.2 Hz); 13C NMR (CDCl3,
J1¼6.8 Hz, J2¼1.2 Hz), 7.55 (2H, t, J¼8.4 Hz), 7.49 (1H, dd, J1¼8.0 Hz,
J2¼1.2 Hz), 7.28 (2H, d, J¼8.8 Hz), 6.82 (1H, t, J¼8.0 Hz), 6.01e5.95 (1H,
m), 5.52 (1H, d, J¼2.8 Hz), 5.26e5.16 (2H, m), 4.83 (2H, dd, J1¼2.8 Hz,
J2¼2.0 Hz), 4.70 (1H, d, J¼2.8 Hz), 4.31 (2H, q, J¼7.2 Hz), 1.30 (3H, t,
J¼7.2 Hz); 13C NMR(CDCl3,100 MHz):
d
166.0,163.4,154.4,144.5,142.9,
100 MHz): d 166.3, 162.8, 154.1, 145.9, 144.1, 137.2, 137.1, 134.7, 133.2,
141.5, 139.0, 136.1, 132.4, 132.2, 131.6, 128.8, 127.8, 126.1, 124.3, 123.3,
131.7, 130.8, 128.8, 127.1, 123.1, 122.0, 117.9, 115.4, 109.4, 95.8, 61.2,

3604
Y.-L. Yang et al. / Tetrahedron 69 (2013) 3593e3607
42.2, 14.2; MS (ESI) m/e 426.1 (MþþNH4); HRMS (ESI) for
C22H20N2O4S (Mþ): 408.1144, Found: 408.1160.
Reaction procedure for the preparation of product 4 also has
been summarized in the Supplementary data and the spectroscopic
data are shown below.
chromatography using silica gel to give the target product 4d (42 mg,
90% overall yield in a stereoselective ratio¼11:1 ((1E,3E)-4d/(1E,3Z)-
4d)). A red solid. Mp for compound 4d¼141e143 ꢁC; IR (CH2Cl2):
n
2923, 2854, 1711, 1690, 1604, 1520, 1464, 1346, 1263, 1204, 1177, 1136,
1097, 1027, 962, 857 cmꢀ1; 1H NMR (400 MHz, CDCl3, TMS):
d 10.04
(1H, d, J¼13.2 Hz), 9.36 (0.09H, d, J¼13.2 Hz, (1E,3Z)-4d), 8.46 (1H, d,
J¼7.2 Hz), 7.99 (2H, d, J¼6.8 Hz), 7.67 (0.09H, d, J¼13.2 Hz, (1E,3Z)-4d),
7.38 (2H, d, J¼8.0 Hz), 7.32e7.24 (9H, m), 7.05 (1H, t, J¼7.6 Hz), 6.72
(1H, d, J¼7.6 Hz), 4.99 (2H, s), 4.97 (0.18H, s, (1E,3Z)-4d), 4.42 (2H, q,
J¼7.2 Hz), 2.40 (3H, s), 2.36 (0.27H, s, (1E,3Z)-4d), 1.44 (3H, t,
J¼7.2 Hz), 1.34 (0.27H, t, J¼7.2 Hz, (1E,3Z)-4d); 13C NMR (CDCl3,
4.1.21. (1E,3E,NE)-N-(1-Benzyl-2-oxoindolin-3-ylidene)-4-(4-
chlorophenyl)-3-(ethoxycarbonyl)buta-1,3-dien-1-amine oxide (1E,3E)-
4a. Following the general procedure, the mixture was purified by
column chromatography using silica gel to give the target product 4a
(44 mg, 90% overall yield in a stereoselective ratio¼33:1 ((1E,3E)-4a/
(1E,3Z)-4a)). A red solid. Mp for compound 4a¼166e167 ꢁC; IR
100 MHz):
d 166.1, 160.4, 146.9, 140.9, 140.4, 136.3, 135.6, 133.2,
(CH2Cl2):
n
2961, 1710, 1691, 1606, 1526, 1464, 1414, 1382, 1347, 1259,
((1E,3E)-4a)
132.0, 131.9, 130.5, 129.5, 129.3, 128.8, 127.7, 127.3, 127.2, 125.7, 125.3,
124.6, 123.0, 118.6, 108.8, 61.6, 43.7, 21.5, 14.2; MS (ESI) m/e 467.2
(MþþH); HRMS (ESI) for C29H26N2O4 (Mþ): 466.1893, Found:
466.1885.
1088,1012, 863 cmꢀ1; 1H NMR (400 MHz, CDCl3, TMS):
d
10.04 (1H, d, J¼13.2 Hz), 8.46 (1H, d, J¼7.2 Hz), 7.94 (1H, s), 7.89 (1H,
d, J¼13.2 Hz), 7.45e7.37 (4H, m), 7.33e7.26 (6H, m), 7.07 (1H, t,
J¼8.0 Hz), 6.74 (1H, d, J¼7.6 Hz), 5.00 (2H, s), 4.42 (2H, q, J¼7.2 Hz),
1.44 (3H, t, J¼7.2 Hz); 13C NMR (CDCl3,100 MHz):
d
((1E,3E)-4a) 165.8,
4.1.25. (1E,3E,NE)-N-(1-Benzyl-2-oxoindolin-3-ylidene)-3-(ethox-
ycarbonyl)-4-(4-(trifluoromethyl)phenyl)buta-1,3-dien-1-amine ox-
ide (1E,3E)-4e. Following the general procedure, the mixture was
purified by column chromatography using silica gel to give the
target product 4e (48 mg, 92% overall yield in a stereoselective
ratio¼13:1 ((1E,3E)-4e/(1E,3Z)-4e)). A red solid. Mp for compound
160.4, 144.9, 141.1, 136.9, 136.0, 135.5, 133.5, 133.1, 132.3, 131.6, 129.1,
128.8, 127.8, 127.3, 126.7, 125.9, 123.7, 123.2, 118.5, 108.9, 61.8, 43.7,
14.2; MS (ESI) m/e 504.2 (MþþNH4); HRMS (ESI) for C28H23N2O4Cl
(Mþ): 486.1346, Found: 486.1335.
4.1.22. (1E,3E,NE)-N-(1-Benzyl-2-oxoindolin-3-ylidene)-4-(3-
bromophenyl)-3-(ethoxycarbonyl)buta-1,3-dien-1-amine oxide (1E,3E)-
4b. Following the general procedure, the mixture was purified by
column chromatography using silica gel to give the target product 4b
(47 mg, 89% overall yield in a stereoselective ratio¼6:1 ((1E,3E)-4b/
(1E,3Z)-4b)). A red solid. Mp for compound 4b¼156e158 ꢁC; IR
4e¼196e198 ꢁC; IR (CH2Cl2):
n
2926, 2858, 1715, 1690, 1606, 1496,
1H NMR
10.05 (1H, d, J¼13.2 Hz), 9.44 (0.07H, d,
1464, 1348, 1323, 1227, 1122, 1067, 1016, 968, 850 cmꢀ1
;
(400 MHz, CDCl3, TMS):
d
J¼13.2 Hz, (1E,3Z)-4e), 8.44 (1H, d, J¼7.6 Hz), 7.98 (1H, s), 7.86 (2H,
d, J¼13.2 Hz), 7.72 (2H, d, J¼8.0 Hz), 7.56 (2H, d, J¼8.0 Hz),
7.32e7.26 (6H, m), 7.06 (1H, t, J¼7.6 Hz), 6.73 (1H, d, J¼8.0 Hz), 4.99
(2H, s), 4.98 (0.14H, s, (1E,3Z)-4e), 4.44 (2H, q, J¼7.2 Hz), 1.46 (3H, t,
J¼7.2 Hz), 1.30 (0.21H, t, J¼7.2 Hz, (1E,3Z)-4e); 13C NMR (CDCl3,
(CH2Cl2):
1261, 1228, 1202, 1175, 1118, 964, 859 cmꢀ1
CDCl3, TMS):
10.04 (1H, d, J¼13.2 Hz), 9.40 (0.15H, d, J¼13.2 Hz,
n
2924, 2854, 1714, 1690, 1605, 1557, 1495, 1463, 1380, 1346,
;
1H NMR (400 MHz,
d
100 MHz): d 165.6, 160.4, 144.2, 141.2, 138.1, 137.2, 135.4, 133.7,
(1E,3Z)-4b), 8.46 (0.15H, d, J¼7.2 Hz, (1E,3Z)-4b), 8.45 (1H, d,
J¼7.2 Hz), 7.90 (1H, s), 7.87 (1H, d, J¼13.2 Hz), 7.64 (0.15H, d,
J¼13.2 Hz, (1E,3Z)-4b), 7.58 (1H, s), 7.54 (1H, d, J¼7.6 Hz), 7.46 (0.15H,
d, J¼6.8 Hz, (1E,3Z)-4b), 7.40 (1H, d, J¼8.0 Hz), 7.35e7.22 (9H, m), 7.05
(1H, d, J¼7.6 Hz), 6.73 (1H, d, J¼7.6 Hz), 6.72 (0.15H, d, J¼7.6 Hz,
(1E,3Z)-4b), 4.99 (2H, s), 4.97 (0.30H, s, (1E,3Z)-4b), 4.42 (2H, q,
J¼7.2 Hz), 4.41 (0.30H, q, J¼7.2 Hz, (1E,3Z)-4b), 1.44 (3H, t, J¼7.2 Hz),
1.33 (0.50H, t, J¼7.2 Hz, (1E,3Z)-4b); 13C NMR (CDCl3, 100 MHz):
132.4, 131.2 (q, J¼32.6 Hz), 130.3, 129.0, 128.8, 128.2, 127.7, 127.3,
127.2, 125.9, 125.7 (q, J¼3.5 Hz), 123.8 (q, J¼270.5 Hz), 123.2, 108.9,
62.0, 43.7,14.2; 19F NMR (282 MHz, CDCl3, CFCl3):
d
ꢀ62.83, ꢀ62.85;
MS (ESI) m/e 521.2 (MþþH); HRMS (ESI) for C29H23F3N2O4 (Mþ):
520.1610, Found: 520.1602.
4.1.26. (1E,3E,NE)-N-(1-Benzyl-2-oxoindolin-3-ylidene)-3-(ethox-
ycarbonyl)-4-(3-methoxyphenyl)buta-1,3-dien-1-amine oxide (1E,3E)-
4f. Following the general procedure, the mixture was purified by
column chromatography using silica gel to give the target product 4f
(45 mg, 93% overall yield in a stereoselective ratio¼14:1 ((1E,3E)-4f/
(1E,3Z)-4f)). A red solid. Mp for compound 4f¼123e125 ꢁC; IR
d
165.7, 160.4, 144.4, 141.1, 137.1, 136.6, 135.5, 133.5, 132.9,132.6,132.2,
130.3, 130.0, 128.8, 128.6, 127.7, 127.5, 127.3, 127.2, 125.8, 123.4, 123.1,
122.8,118.5,108.8, 61.8, 43.7, 14.2; MS (ESI) m/e 531.1 (MþþH); HRMS
(ESI) for C28H23N2O4Br (Mþ): 530.0841, Found: 530.0835.
(CH2Cl2):
1135, 1118, 1097, 1077, 1027, 963, 866 cmꢀ1
CDCl3, TMS):
n
2925, 2853,1712,1690,1605,1571, 1494, 1463,1346,1246,
4.1.23. (1E,3E,NE)-N-(1-Benzyl-2-oxoindolin-3-ylidene)-3-(ethox-
ycarbonyl)-4-(2-methoxyphenyl)buta-1,3-dien-1-amine oxide (1E,3E)-
4c. Following the general procedure, the mixture was purified by
column chromatography using silica gel to give the target product 4c
(40 mg, 83% overall yield in a stereoselective ratio¼50:1 ((1E,3E)-4c/
(1E,3Z)-4c)). A red solid. Mp for compound 4c¼201e203 ꢁC; IR
;
1H NMR (400 MHz,
d
((1E,3E)-4f) 10.03 (1H, d, J¼13.6 Hz), 8.46 (1H, d,
J¼7.6 Hz), 7.99 (1H, d, J¼12.4 Hz), 7.39e7.25 (7H, m), 7.05 (1H, t,
J¼8.0 Hz), 6.97 (1H, d, J¼8.0 Hz), 6.73 (1H, d, J¼8.0 Hz), 4.99 (2H, s),
4.42 (2H, q, J¼7.2 Hz), 3.84 (3H, s), 1.45 (3H, t, J¼7.2 Hz); 13C NMR
(CDCl3, 100 MHz):
d ((1E,3E)-4f) 166.0, 160.4, 159.6, 146.5, 141.0,
(CH2Cl2):
n
2923, 2852, 1712, 1697, 1604, 1524, 1457, 1345, 1249, 1177,
((1E,3E)-
136.5, 135.6, 133.3, 132.0, 129.8, 128.8, 127.7, 127.3, 126.4, 124.3, 123.1,
122.9, 118.6, 116.0, 115.2, 108.8, 61.7, 55.3, 43.7, 14.2; MS (ESI) m/e
483.2 (MþþH); HRMS (ESI) for C29H26N2O5 (Mþ): 482.1842, Found:
482.1832.
1097,1025, 971, 855 cmꢀ1; 1H NMR (400 MHz, CDCl3, TMS):
d
4c) 10.06 (1H, d, J¼13.2 Hz), 8.45 (1H, dd, J1¼7.6 Hz, J2¼0.8 Hz), 8.22
(1H, s), 7.91 (1H, dd,J1¼13.2 Hz, J2¼0.8 Hz), 7.42e7.24 (9H, m), 7.04 (1H,
dt, J1¼8.4 Hz, J2¼0.4 Hz), 6.94 (1H, d, J¼8.0 Hz), 6.72 (1H, d, J¼7.6 Hz),
5.00 (2H, s), 4.42 (2H, q, J¼7.2 Hz), 3.89 (3H, s),1.44 (3H, t, J¼7.2 Hz); 13C
4.1.27. (1E,3E,NE)-N-(1-Benzyl-2-oxoindolin-3-ylidene)-4-
(3,4-dichlorophenyl)-3-(ethoxycarbonyl)buta-1,3-dien-1-amine oxide
(1E,3E)-4g. Following the general procedure, the mixture was puri-
fied by column chromatography using silica gel to give the target
NMR (CDCl3, 100 MHz): d ((1E,3E)-4c) 166.1, 160.4, 158.1, 143.4, 140.9,
136.1, 135.6, 133.1, 131.9, 131.60, 131.57, 128.8, 127.7, 127.3, 125.8, 125.7,
125.0, 123.8, 123.0, 120.7, 118.6, 110.7, 108.8, 61.5, 55.6, 43.7, 14.2; MS
(ESI) m/e 483.2 (MþþH); HRMS (ESI) for C29H26N2O5 (Mþ): 482.1842,
Found: 482.1835.
product 4g (41 mg, 79% overall yield in
a stereoselective
ratio¼4:1 ((1E,3E)-4g/(1E,3Z)-4g)). A red solid. Mp for compound
4g¼211e213 ꢁC; IR (CH2Cl2):
n
2962, 1718, 1689, 1607, 1522, 1465,
;
4.1.24. (1E,3E,NE)-N-(1-benzyl-2-oxoindolin-3-ylidene)-3-(ethox-
ycarbonyl)-4-p-tolylbuta-1,3-dien-1-amine oxide (1E,3E)-4d. Follow-
ing the general procedure, the mixture was purified by column
1350, 1259, 1089, 1017, 863 cmꢀ1 1H NMR (400 MHz, CDCl3, TMS):
d
10.03 (1H, d, J¼13.2 Hz), 9.42 (0.25H, d, J¼13.2 Hz, (1E,3Z)-4g), 8.46
(1H, d, J¼6.8 Hz), 7.86e7.84 (1H, m), 7.84e7.82 (0.25H, m), 7.56

Y.-L. Yang et al. / Tetrahedron 69 (2013) 3593e3607
3605
(0.25H, s, (1E,3Z)-4g), 7.55e7.53 (1H, m), 7.44 (0.25H, d, J¼8.4 Hz,
(1E,3Z)-4g), 7.36e7.23 (9H, m), 7.10e7.05 (1H, m), 6.74 (1H, d,
J¼8.0 Hz), 6.73 (0.25H, d, J¼8.0 Hz, (1E,3Z)-4g), 5.00 (2H, s), 4.98
(0.50H, s, (1E,3Z)-4g), 4.42 (2H, q, J¼7.2 Hz), 4.31 (0.50H, q, J¼7.2 Hz,
(1E,3Z)-4g), 1.44 (3H, t, J¼7.2 Hz), 1.35 (0.75H, t, J¼7.2 Hz, (1E,3Z)-4g);
118.6, 108.8, 61.9, 43.7, 14.2; MS (ESI) m/e 459.1 (MþþH); HRMS
(ESI) for C26H22N2O4S (Mþ): 458.1300, Found: 458.1292.
4.1.31. (1E,3E,NE)-N-(1-Benzyl-5-methyl-2-oxoindolin-3-ylidene)-
4-(3-bromophenyl)-3-(ethoxycarbonyl)buta-1,3-dien-1-amine
oxide
13C NMR (CDCl3, 100 MHz):
d
165.5, 160.4, 143.1, 141.1, 137.3, 135.5,
(1E,3E)-4l. Following the general procedure, the mixture was puri-
fied by column chromatography using silica gel to give the target
product 4l (48 mg, 88% overall yield in a stereoselective ratio¼5:1
((1E,3E)-4l/(1E,3Z)-4l). A red solid. Mp for compound 4l¼155e157 ꢁC;
134.6, 134.0, 133.7, 132.4, 131.9, 130.8, 129.2, 128.8, 127.9, 127.8, 127.3,
127.2, 125.9, 123.2, 123.0, 118.5, 108.9, 61.9, 43.7, 14.2; MS (ESI) m/e
521.1 (MþþH); HRMS (ESI) for C28H22Cl2N2O4 (Mþ): 520.0957, Found:
520.0954.
IR (CH2Cl2):
1219, 1183, 1105, 1075, 1026, 908, 803 cmꢀ1
CDCl3, TMS):
10.04 (1H, d, J¼13.2 Hz), 9.41 (0.20H, d, J¼13.2 Hz,
n 2979, 2853, 1715, 1689, 1522, 1482, 1376, 1327, 1265,
;
1H NMR (400 MHz,
4.1.28. (1E,3E,NE)-N-(1-Benzyl-2-oxoindolin-3-ylidene)-3-(ethox-
ycarbonyl)-4-(3,4,5-trimethoxyphenyl)buta-1,3-dien-1-amine ox-
ide (1E,3E)-4h. Following the general procedure, the mixture was
purified by column chromatography using silica gel to give the
target product 4h (50 mg, 92% overall yield in a stereoselective
ratio¼>99:1 ((1E,3E)-4h/(1E,3Z)-4h)). A red solid. Mp for com-
d
(1E,3Z)-4l), 8.31 (1H, s), 7.89 (1H, s), 7.87 (2H, d, J¼13.6 Hz), 7.63
(0.20H, d, J¼13.2 Hz, (1E,3Z)-4l), 7.58 (1H, s), 7.54 (1H, d, J¼8.0 Hz),
7.47 (0.20H, d, J¼8.0 Hz, (1E,3Z)-4l), 7.41 (1H, d, J¼7.6 Hz), 7.36e7.23
(7H, m, (1E,3E)-4l & (1E,3Z)-4l), 7.08 (1H, d, J¼8.0 Hz), 6.99 (0.20H, s,
(1E,3Z)-4l), 6.61 (1H, d, J¼8.0 Hz), 6.60 (0.20H, d, J¼8.0 Hz, (1E,3Z)-4l),
4.97 (2H, s), 4.95 (0.40H, s), 4.42 (2H, q, J¼7.2 Hz), 4.41 (0.40H, q,
J¼7.2 Hz, (1E,3Z)-4l), 2.33 (0.60H, s, (1E,3Z)-4l), 2.31 (3H, s), 1.44 (3H,
t, J¼7.2 Hz), 1.29 (0.60H, t, J¼7.2 Hz, (1E,3Z)-4l); 13C NMR (CDCl3,
pound 4h¼193e195 ꢁC; IR (CH2Cl2):
n 2927, 1711, 1692, 1606, 1520,
1464, 1431, 1346, 1333, 1257, 1178, 1125, 1098, 1005, 966,
858 cmꢀ1 1H NMR (400 MHz, CDCl3, TMS):
; d ((1E,3E)-4h) 10.02
(1H, d, J¼13.2 Hz), 8.46 (1H, d, J¼7.6 Hz), 8.10 (1H, d, J¼13.2 Hz),
7.94 (1H, s), 7.32e7.25 (6H, m), 7.06 (1H, t, J¼7.6 Hz), 6.74 (3H, d,
J¼6.0 Hz), 5.00 (2H, s), 4.42 (2H, q, J¼7.2 Hz), 3.93 (3H, s), 3.91 (6H,
100 MHz): d 165.7, 160.4, 144.3, 139.0, 137.0, 136.7, 135.6, 133.8, 133.0,
132.8, 132.7, 132.5, 130.3, 128.8, 128.5, 127.7, 127.5, 127.2, 127.1, 126.4,
123.2, 122.8, 118.5, 108.7, 61.8, 43.7, 21.0, 14.2; MS (ESI) m/e 545.1
(MþþH); HRMS (ESI) for C29H25N2O4Br (Mþ): 544.0998, Found:
544.0989.
s), 1.45 (3H, t, J¼7.2 Hz); 13C NMR (CDCl3, 100 MHz):
d ((1E,3E)-4h)
166.0, 160.5, 153.2, 146.4, 140.9, 139.7, 136.3, 135.6, 133.2, 132.0,
130.0, 128.8, 127.7, 127.8, 127.3, 125.7, 125.4, 124.6, 123.1, 118.6,
108.8, 108.0, 61.6, 61.0, 56.2, 43.7, 14.2; MS (ESI) m/e 543.2
(MþþH); HRMS (ESI) for C31H30N2O7 (Mþ): 542.2053, Found:
542.2043.
4.1.32. (1E,3E,NE)-N-(1-Benzyl-5-methyl-2-oxoindolin-3-ylidene)-3-
(ethoxycarbonyl)-4-(naphthalen-2-yl)buta-1,3-dien-1-amine oxide
(1E,3E)-4m. Following the general procedure, the mixture was
purified by column chromatography using silica gel to give the
target product 4m (49 mg, 95% overall yield in a stereoselective
ratio¼8:1 ((1E,3E)-4m/(1E,3Z)-4m)). A red solid. Mp for compound
4.1.29. (1E,3E,NE)-N-(1-Benzyl-2-oxoindolin-3-ylidene)-3-(ethox-
ycarbonyl)-4-(naphthalen-2-yl)buta-1,3-dien-1-amine oxide (1E,3E)-
4i. Following the general procedure, the mixture was purified by
column chromatography using silica gel to give the target product
4i (48 mg, 96% overall yield in a stereoselective ratio¼25:1 ((1E,3E)-
4i/(1E,3Z)-4i)). A red solid. Mp for compound 4i¼181e182 ꢁC; IR
4m¼198e200 ꢁC; IR (CH2Cl2):
n
2923, 2854, 1712, 1686, 1614, 1519,
1H
10.09 (1H, d, J¼13.2 Hz), 9.43 (0.12H,
1481, 1453, 1367, 1326, 1182, 1122, 1104, 1025, 955, 858 cmꢀ1
;
NMR (400 MHz, CDCl3, TMS):
d
d, J¼13.2 Hz, (1E,3Z)-4m), 8.33 (0.12H, s, (1E,3Z)-4m), 8.30 (1H, s),
8.16 (1H, s), 8.07 (1H, d, J¼12.8 Hz), 7.96 (1H, s), 7.92e7.79 (3H, m),
7.72 (0.12H, d, J¼13.2 Hz, (1E,3Z)-4m), 7.59e7.49 (3H, m), 7.33e7.22
(6H, m, (1E,3E)-4m & (1E,3Z)-4m), 7.06 (1H, d, J¼8.0 Hz), 6.60 (1H,
d, J¼8.0 Hz), 4.97 (2H, s), 4.95 (0.24H, s, (1E,3Z)-4m), 4.45 (2H, q,
J¼7.2 Hz), 2.33 (0.24H, s, (1E,3Z)-4m), 2.29 (3H, s), 1.47 (3H, t,
J¼7.2 Hz), 1.31 (0.36H, t, J¼7.2 Hz, (1E,3Z)-4m); 13C NMR (CDCl3,
(CH2Cl2):
1347, 1225, 1177, 1097, 1077, 969, 859 cmꢀ1
CDCl3, TMS):
n
2924, 2854, 1713, 1693, 1607, 1521, 1496, 1464, 1381,
;
1H NMR (400 MHz,
d
((1E,3E)-4i) 10.09 (1H, d, J¼13.2 Hz), 8.45 (1H, d,
J¼7.6 Hz), 8.17 (1H, s), 8.07 (1H, d, J¼13.2 Hz), 7.96 (1H, s), 7.90 (2H,
d, J¼8.4 Hz), 7.85 (1H, d, J¼7.6 Hz), 7.59e7.50 (3H, m), 7.32e7.23
(6H, m), 7.04 (1H, t, J¼7.6 Hz), 6.72 (1H, d, J¼7.6 Hz), 4.99 (2H, s),
4.45 (2H, q, J¼7.2 Hz), 1.47 (3H, t, J¼7.2 Hz); 13C NMR (CDCl3,
100 MHz):
d 166.1, 160.5, 146.5, 138.9, 136.7, 135.7, 133.6, 133.5,
100 MHz):
d
166.1, 160.4, 146.7, 141.0, 136.7, 135.6, 133.6, 133.3,
133.0,132.7, 132.6, 132.3, 131.0,128.8,128.5, 127.7, 127.4, 127.3, 127.2,
127.0, 126.7,126.4, 126.3, 124.2, 118.6, 108.6, 61.7, 43.7, 20.9, 14.2; MS
(ESI) m/e 517.2 (MþþH); HRMS (ESI) for C33H28N2O4 (Mþ):
516.2049, Found: 516.2037.
133.0,132.2,132.0,131.0,128.8,128.5,127.7,127.4, 127.3,127.0,126.7,
126.2, 125.7, 124.4, 123.1, 118.6, 108.8, 61.7, 43.7, 14.2; MS (ESI) m/e
503.2 (MþþH); HRMS (ESI) for C32H26N2O4 (Mþ): 502.1893, Found:
502.1882.
4.1.33. (1E,3E,NE)-N-(1-Allyl-7-bromo-2-oxoindolin-3-ylidene)-4-
4.1.30. (1E,3E,NE)-N-(1-Benzyl-2-oxoindolin-3-ylidene)-3-(ethox-
ycarbonyl)-4-(thiophen-2-yl)buta-1,3-dien-1-amine oxide (1E,3E)-
4j. Following the general procedure, the mixture was purified by
column chromatography using silica gel to give the target product
4j (42 mg, 92% overall yield in a stereoselective ratio¼9:1 ((1E,3E)-
4j/(1E,3Z)-4j). A red solid. Mp for compound 4j¼188e191 ꢁC; IR
(4-chlorophenyl)-3-(ethoxycarbonyl)buta-1,3-dien-1-amine
(1E,3E)-4n. Following the general procedure, the mixture was pu-
rified by column chromatography using silica gel to give the target
oxide
product 4n (42 mg, 82% overall yield in
a stereoselective
ratio¼7:1 ((1E,3E)-4n/(1E,3Z)-4n). A red solid. Mp for compound
4n¼144e146 ꢁC; IR (CH2Cl2):
n 2925, 2853, 1715, 1694, 1614, 1518,
(CH2Cl2):
1024, 1095, 1016, 959, 858 cmꢀ1; 1H NMR (400 MHz, CDCl3, TMS):
10.09 (1H, d, J¼13.2 Hz), 8.53 (1H, d, J¼7.6 Hz), 8.31 (1H, d,
n
2910, 2862, 1689, 1607, 1519, 1463, 1415, 1346, 1261,
1466, 1438, 1412, 1330, 1279, 1166, 1089, 1012, 951, 907, 822 cmꢀ1
;
1H NMR (400 MHz, CDCl3, TMS):
d
10.01 (1H, d, J¼13.2 Hz), 9.37
d
(0.14H, d, J¼13.2 Hz, (1E,3Z)-4n), 8.55 (1H, d, J¼7.6 Hz), 7.95 (1H, s),
7.85 (1H, d, J¼13.2 Hz), 7.62 (0.14H, d, J¼13.2 Hz, (1E,3Z)-4n),
7.48e7.38 (5H, m, (1E,3E)-4n & (1E,3Z)-4n), 7.30 (1H, d, J¼25.6 Hz),
6.98e6.93 (1H, m), 6.04e5.94 (1H, m), 5.20 (1H, d, J¼10.8 Hz), 5.14
(1H, d, J¼17.2 Hz), 4.89e4.87 (2H, m), 4.41 (2H, q, J¼7.2 Hz), 1.43
(3H, t, J¼7.2 Hz), 1.32 (0.42H, t, J¼7.2 Hz, (1E,3Z)-4n); 13C NMR
J¼7.6 Hz), 8.07 (1H, s), 7.85 (0.12H, d, J¼7.6 Hz, (1E,3Z)-4j), 7.63 (1H,
d, J¼5.2 Hz), 7.45 (1H, d, J¼3.6 Hz), 7.32e7.25 (7H, m), 7.17 (1H, t,
J¼3.6 Hz), 7.07 (1H, t, J¼3.6 Hz), 6.93 (0.12H, t, J¼3.6 Hz, (1E,3Z)-4j),
6.73 (1H, d, J¼7.6 Hz), 4.99 (2H, s), 4.94 (0.24H, s, (1E,3Z)-4j), 4.41
(2H, q, J¼7.2 Hz), 4.29 (0.24H, q, J¼7.2 Hz, (1E,3Z)-4j), 1.44 (3H, t,
J¼7.2 Hz), 1.29 (0.36H, t, J¼7.2 Hz, (1E,3Z)-4j); 13C NMR (CDCl3,
(CDCl3, 100 MHz):
d 165.7, 160.6, 145.4, 138.1, 137.6, 137.1, 136.1,
100 MHz):
d
165.9, 160.4, 141.0, 138.0, 137.9, 136.6, 135.5, 134.6,
133.0, 132.7, 132.3, 131.6, 130.3, 129.1, 128.8, 126.6, 124.7, 124.3,
124.2, 121.5, 116.6, 102.1, 61.8, 43.0, 14.2; MS (ESI) m/e 515.0
133.3, 132.4, 132.1, 128.8,128.1,127.7,127.3,125.9, 123.9, 123.1, 122.2,

3606
Y.-L. Yang et al. / Tetrahedron 69 (2013) 3593e3607
(MþþH); HRMS (ESI) for C24H20BrClN2O4 (Mþ): 514.0295, Found:
column chromatography using silica gel to give the target product 4r
(41 mg, 95% overall yield in a stereoselective ratio¼20:1 ((1E,3E)-4r/
(1E,3Z)-4r)). A red solid. Mp for ((1E,3E)-4r)¼50e53 ꢁC; mp for
514.0286.
4.1.34. (1E,3E,NE)-N-(1-Allyl-7-bromo-2-oxoindolin-3-ylidene)-3-
((1E,3Z)-4r)¼48e51 ꢁC; IR (CH2Cl2):
n 3116, 2925, 2853, 1712, 1692,
(ethoxycarbonyl)-4-p-tolylbuta-1,3-dien-1-amine
oxide
(1E,3E)-
1604, 1572, 1519, 1430, 1378, 1344, 1289, 1175, 1117, 1022, 964, 930,
4o. Following the general procedure, the mixture was purified by
column chromatography using silica gel to give the target product 4o
(38 mg, 84% overall yield in a stereoselective ratio¼18:1 ((1E,3E)-4o/
(1E,3Z)-4o)). A red solid. Mp for compound 4o¼118e120 ꢁC; IR
865 cmꢀ1; 1H NMR (400 MHz, CDCl3, TMS):
d ((1E,3E)-4r) 9.98 (1H, d,
J¼13.2 Hz), 8.45 (1H, d, J¼7.6 Hz), 7.97 (1H, d, J¼13.2 Hz), 7.968 (1H,
s), 7.36 (2H, q, J¼9.2 Hz), 7.07 (2H, dd, J1¼12.0 Hz, J2¼7.6 Hz), 6.97
(2H, d, J¼6.4 Hz), 6.82 (1H, d, J¼8.0 Hz), 5.90e5.81 (1H, m), 5.25 (1H,
d, J¼6.8 Hz), 5.22 (1H, s), 4.45e4.39 (4H, m), 3.84 (3H, s), 1.44 (3H, t,
(CH2Cl2):
1127, 1085, 1019, 948, 878 cmꢀ1
10.02 (1H, d, J¼13.2 Hz), 9.34 (0.06H, d, J¼13.2 Hz, (1E,3Z)-4o), 8.57
n 2923, 2853, 1693,1602,1590,1517, 1438,1412,1329,1204,
;
1H NMR (400 MHz, CDCl3, TMS):
J¼7.2 Hz); 1H NMR (400 MHz, CDCl3, TMS):
d ((1E,3Z)-4r) 9.33 (1H, d,
d
J¼13.2 Hz), 8.48 (1H, d, J¼8.4 Hz), 7.65 (1H, d, J¼13.2 Hz), 7.38e7.28
(2H, m), 7.23e7.21 (2H, m), 7.11 (1H, t, J¼7.6 Hz), 7.04 (1H, s),
7.00e6.89 (2H, m), 6.85e6.80 (1H, m), 5.89e5.81 (1H, m), 5.28e5.22
(2H, m), 4.43e4.37 (4H, m), 3.81 (3H, s), 1.32 (3H, t, J¼8.0 Hz); 13C
(1H, dd, J1¼8.0 Hz, J2¼0.8 Hz), 8.01 (1H, s), 7.95 (1H, d, J¼13.2 Hz),
7.64 (0.06H, d, J¼13.2 Hz, (1E,3Z)-4o), 7.46 (1H, dd, J1¼8.0 Hz,
J2¼0.8 Hz), 7.37 (1H, d, J¼8.0 Hz), 7.27 (1H, d, J¼8.0 Hz), 7.17 (0.12H, d,
J¼8.0 Hz, (1E,3Z)-4o), 6.94 (1H, t, J¼8.0 Hz), 6.03e5.96 (1H, m), 5.19
(1H, dd, J1¼8.0 Hz, J2¼0.8 Hz), 5.14 (1H, dd, J1¼8.0 Hz, J2¼0.8 Hz),
4.89e4.88 (2H, m), 4.41 (2H, q, J¼7.2 Hz), 2.41 (3H, s), 2.37 (0.18H, s,
(1E,3Z)-4o),1.43 (3H, t, J¼7.2 Hz), 1.33 (0.18H, t, J¼7.2 Hz, (1E,3Z)-4o);
NMR (CDCl3,100 MHz): d ((1E,3E)-4r) 166.0,160.0,159.6,146.4,141.0,
136.4, 135.9, 133.3, 132.0, 131.1, 129.8, 126.4, 125.7, 124.2, 123.0, 122.8,
118.5, 117.7, 115.9, 115.2, 108.7, 61.6, 55.3, 42.2, 14.2; 13C NMR (CDCl3,
100 MHz): d ((1E,3Z)-4r) 167.4, 160.0, 159.5, 144.2, 141.1, 140.7, 135.9,
13C NMR (CDCl3, 100 MHz):
d
166.0, 160.7, 147.4, 140.6, 137.9, 137.4,
133.2, 132.2, 131.1, 130.6, 129.4, 128.7, 126.0, 123.1, 118.4, 118.0, 117.8,
115.5, 108.8, 95.1, 61.9, 55.2, 42.3, 14.2; MS (ESI) m/e ((1E,3E)-4r)
433.2 (MþþH); HRMS (ESI) for C25H24N2O5 (Mþ): 432.1685, Found:
432.1680; MS (ESI) m/e ((1E,3Z)-4r) 450.2 (MþþNH4); HRMS (ESI)
for C25H24N2O5 (Mþ): 432.1685, Found: 432.1683.
136.5, 132.7, 132.0, 131.9, 130.6, 129.6, 125.3, 125.2, 124.6, 124.1, 121.6,
116.6, 102.1, 102.0, 61.6, 43.0, 21.5, 14.2; MS (ESI) m/e 495.1 (MþþH);
HRMS (ESI) for C25H23BrN2O4 (Mþ): 494.0841, Found: 494.0833.
4.1.35. (1E,3E,NE)-N-(1-Allyl-6-methyl-2-oxoindolin-3-ylidene)-4-(4-
chlorophenyl)-3-(ethoxycarbonyl)buta-1,3-dien-1-amine oxide (1E,3E)-
4p. Following the general procedure, the mixture was purified by
column chromatography using silica gel to give the target product 4p
(41 mg, 91% overall yield in a stereoselective ratio¼8:1 ((1E,3E)-4p/
(1E,3Z)-4p)). A red solid. Mp for compound 4p¼165e166 ꢁC; IR
Acknowledgements
We thank the Shanghai Municipal Committee of Science and
Technology (11JC1402600), National Basic Research Program of
China (973)-2010CB833302, the Fundamental Research Funds for
the Central Universities and the National Natural Science Founda-
tion of China for financial support (20902019, 20872162, 20672127,
21121062, 21102166, 20732008, 20772030 and 20702059).
(CH2Cl2): n 2922, 2853, 1713, 1692, 1588, 1521, 1486, 1445, 1377, 1341,
1306, 1265, 1123, 1089, 1012, 965, 908, 851 cmꢀ1; 1H NMR (400 MHz,
CDCl3, TMS):
d
9.94 (1H, d, J¼13.2 Hz), 9.29 (0.12H, d, J¼13.2 Hz,
(1E,3Z)-4p), 8.32 (1H, d, J¼7.6 Hz), 7.90 (1H, s), 7.86 (1H, d, J¼13.2 Hz),
7.60 (0.12H, d, J¼13.2 Hz, (1E,3Z)-4p), 7.44e7.32 (4H, m), 6.89 (1H, d,
J¼8.0 Hz), 6.63 (1H, s), 5.89e5.82 (1H, m), 5.26e5.22 (2H, m),
4.44e4.37 (4H, m), 2.39 (3H, s), 1.77 (0.36H, s, (1E,3Z)-4p), 1.43 (3H, t,
J¼7.2 Hz), 1.32 (0.36H, t, J¼7.2 Hz, (1E,3Z)-4p); 13C NMR (CDCl3,
Supplementary data
The 1H and 13C NMR spectroscopic data and charts of the
compounds and X-ray crystal data of 3j, (1E,3E)-4a, (1E,3Z)-4r are
included in the Supplementary data. Supplementary data related to
this article can be found online at http://dx.doi.org/10.1016/
j.tet.2013.02.070.
100 MHz): d 165.8, 160.3, 144.5, 143.6, 141.4, 136.7, 135.8, 133.5, 133.1,
131.5, 131.1, 129.0, 126.8, 125.8, 123.8, 123.0, 117.6, 116.0, 109.6, 61.7,
42.1, 22.6, 14.2; MS (ESI) m/e 451.1 (MþþH); HRMS (ESI) for
C25H23ClN2O4 (Mþ): 450.1346, Found: 450.1335.
References and notes
4.1.36. (1E,3E,NE)-N-(1-Allyl-2-oxoindolin-3-ylidene)-4-(3-
bromophenyl)-3-(ethoxycarbonyl)buta-1,3-dien-1-amine oxide (1E,3E)-
4q. Following the general procedure, the mixture was purified by
column chromatography using silica gel to give the target product 4q
(45 mg, 94% overall yield in a stereoselective ratio¼5:1 ((1E,3E)-4q/
(1E,3Z)-4q)). A red solid. Mp for compound 4q¼117e119 ꢁC; IR
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1186, 1104, 1092, 965, 923, 861 cmꢀ1
TMS):
n
3115, 2979, 1691, 1645, 1604, 1556, 1463, 1377, 1343, 1267,
;
1H NMR (400 MHz, CDCl3,
d
9.99 (1H, d, J¼13.2 Hz), 9.35 (0.20H, d, J¼13.2 Hz, (1E,3Z)-4q),
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J¼8.0 Hz), 6.82 (1H, d, J¼8.0 Hz), 5.90e5.81 (1H, m), 5.26 (1H, d,
J¼6.4 Hz), 5.22 (1H, s), 4.44e4.39 (4H, m), 1.44 (3H, t, J¼7.2 Hz), 1.32
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160.0, 144.3, 141.4, 137.0, 136.6, 133.8, 133.6, 132.9, 132.6, 132.2, 131.1,
131.0, 130.3, 130.0, 128.6, 127.5, 125.8, 123.3, 123.1, 122.8, 118.4, 117.8,
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ycarbonyl)-4-(3-methoxyphenyl)buta-1,3-dien-1-amine oxide (1E,3E)-
4r. Following the general procedure, the mixture was purified by

Y.-L. Yang et al. / Tetrahedron 69 (2013) 3593e3607
3607
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ꢀ
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