Synthesis of spiro[furan-3,3′-indolin]-2′-ones by PET-catalyzed [3+2] reactions of spiro[indoline-3,2′-oxiran]-2-ones with electron-rich olefins

Article abstract of DOI:10.1016/j.tet.2011.12.018

An efficient procedure for the synthesis of spiro[furan-3,3′-indolin] -2-ones and dispiro[cycloalkane-1,2′-furan-3′,3″-indolin]- 2″-ones has been achieved in high yields and stereoselectivity by photoinduced electron transfer-catalyzed [3+2] reactions of substituted spiro[indoline-3,2′-oxiran]-2-ones with olefins. The reactions proceed by ring opening of spiro[indoline-3,2′-oxiran]-2-ones via C _β-O bond cleavage and subsequent cycloaddition with olefins by using 2,4,6-triphenylpyrylium tetarfluoroborate (TPT) as a sensitizer.

Full text of DOI:10.1016/j.tet.2011.12.018

Tetrahedron 68 (2012) 1483e1491
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Synthesis of spiro[furan-3,30-indolin]-20-ones by PET-catalyzed [3þ2] reactions
of spiro[indoline-3,20-oxiran]-2-ones with electron-rich olefins
*
Lihong Wang, Zhanshan Li, Lianhong Lu, Wei Zhang
State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Tianshui Road 222, Lanzhou 730000, PR China
a r t i c l e i n f o
a b s t r a c t
An efficient procedure for the synthesis of spiro[furan-3,30-indolin]-2-ones and dispiro[cycloalkane-1,20-
furan-30,300-indolin]-200-ones has been achieved in high yields and stereoselectivity by photoinduced
electron transfer-catalyzed [3þ2] reactions of substituted spiro[indoline-3,20-oxiran]-2-ones with ole-
fins. The reactions proceed by ring opening of spiro[indoline-3,20-oxiran]-2-ones via CbeO bond cleavage
and subsequent cycloaddition with olefins by using 2,4,6-triphenylpyrylium tetarfluoroborate (TPT) as
a sensitizer.
Article history:
Received 26 September 2011
Received in revised form 1 December 2011
Accepted 9 December 2011
Available online 19 December 2011
Keywords:
Ó 2011 Elsevier Ltd. All rights reserved.
Photoinduced electron transfer
[3þ2] Cycloaddition
Spiro[furan-3,30-indolin]-2-ones
Spiro[indoline-3,20-oxiran]-2-ones
2,4,6-Triphenylpyrylium tetarfluoroborate
1. Introduction
tetrahydrofuran, dihydropyrrole, pyrrolidine, and cyclopentane were
formed (Scheme 1).
Photoinduced electron transfer (PET) catalysis is an important tool
in modern synthetic photochemistry.1 Increasing research activity in
PET processes has focused not only on mechanism but also in dis-
covering new synthetically useful reactions. The advantages of the
PET-catalyzed reactions over the classical photoreactions lie in the
increase of reaction selectivity, reaction rate, and the yields of prod-
ucts. For example, the PET-catalyzed ring opening of oxiranes,2 azir-
ines,3 aziridines,4 and cyclopropanes5 and subsequentintermolecular
or intramolecular [3þ2] reactions with alkenes or alkynes provided
a more efficient route to synthesis of cyclic compounds than simple
photolytic 1,3-diplar cycloaddition. In these reactions, the high active
radical cations of oxiranes, azirines, aziridines, and cyclopropanes
were first produced by photoinduced electron transfer from
these compounds to excited oxidative photosensitizers like 1,4-
dicyanophthalene (DCN), 9,10-dicyanoanthracene (DCA) or 2,4,6-
triphenylpyrylium tetrafluoroborate (TPT) and the CeC bond cleav-
age of these three-membered cyclic radical cations occurred quickly
to produce 1,3-radical cations, which could be captured by alkenes or
alkynes to give the five-membered cyclic radical cations; after the
back electron transfer from the photosensitizer radical anions
to these five-membered cyclic radical cations, polysubstituted
hv
Sens
.
+
+
X
X
X
.
-
R2
R1
Sens
R1
R2
.
R1
R2
+
X = O, N, C
Sene = DCN, DCA, TPT
.
-
.
Sens Sens
+
X
X
R1
R2
R1
R2
R3
R3
R3
Scheme 1. PET-catalyzed [3þ2] reactions of oxirane, azirine, aziridine, and cyclopro-
panes with olefins.
Recently, we reported a novel synthesis of polysubstituted tet-
rahydrofurans by PET-catalyzed [3þ2] reactions of oxir-
anecarbonitriles with electron-rich olefins via TPT-sensitized CbeO
bond cleavage of oxiranecarbonitriles and subsequent [3þ2] cy-
cloaddition with olefins (Scheme 2),6 which was much different
from the reported DCN or DCA sensitized [3þ2] cycloaddition of
oxiranes with olefins via CeC bond cleavage of oxiranes.2 In the
reactions, the radical cations of oxiranes were first produced by
electron transfer from oxiranes to excited TPT, the oxirane radical
cations underwent CbeO bond cleavage and subsequent [3þ2] cy-
cloaddition with olefins produced tetrahydrofuran radical cations,
which finally accepted an electron from TPT radical afforded the
products and regenerated TPT cation (Scheme 3).6
* Corresponding author. Tel.: þ86 931 8912545; fax: þ86 931 8625657; e-mail
address: zhangwei6275@lzu.edu.cn (W. Zhang).
0040-4020/$ e see front matter Ó 2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2011.12.018

1484
L. Wang et al. / Tetrahedron 68 (2012) 1483e1491
(2-bromophenyl)3-furan-3-carboxyamide;10c Menendez reported
the synthesis of dihydrospiro[furan-30,3-indole]-20,2-diones by one-
pot transformation of 3-(4-hydroxyalkyl)indoles under Swern con-
ditions;10d GiorgieRenault reported the synthesis of dihydrospiro
[furan-30,3-indole]-20,2-diones by oxidative rearrangement of 3,4-
dihydropyrano[3,4-b]indol-1-ones with m-chloroperbenzoic acid.10e
ꢀ
2
2
O
O
NC
NC
R
R
hv
O
1
1
3
R
R
3
R
R
2
CN
1
TPT
H
2
R
+
+
CH Cl
2
R
3
2
R
MeO
MeO
MeO
1
R
= H, Me, Ph
= Ph
R
= H, CN, CO2Et
3
R
Scheme 2. TPT-catalyzed [3þ2] reaction of oxiranes with olefins.
O
O
O
R2
R3
O
n
n
O
O
N
N
TPT
N
R
H
R1
hv
Ia-b
Ic
IIa-b
Ph
.
O
O
H
*
CN
H
CN
H
TPT
.
+
H
Ph
O
Ph
2. Results and discussion
MeO
MeO
MeO
Ph
.
.
We first examined the photoreaction of 30,30-dimethylspiro
[indoline-3,20-oxiran]-2-ones (1a) with styrene (2a) in the pres-
ence of different sensitizers, such as TPT, DCA, DCN, and chloranil.
The deaerated anhydrous CH2Cl2 solutions of 1a with 2a and
a catalytic amount of photosensitizers (5% equiv) were irradiated at
.
+
Ph
H
O
H
+
Ph
O
CN
Ph
O
Ph
H
CN
H
H
MeO
l
ꢀ350 nm at ambient temperature and the progress of the reaction
Ph
H
Ph
was monitored by TLC chromatography at different interval. It was
found that the reaction of 1a and 2a could afford the [3þ2] prod-
ucts, 3,3-dimethylspiro[furan-3,30-indolin]-20-ones 3a and 4a (8:1),
in high yields only under the catalysis of TPT and the reaction was
completely regioselective as depicted in Scheme 5.
O
+
H
CN
Ph
O
Ph
H
+
(TPT)
MeO
Scheme 3. Mechanism of TPT-catalyzed [3þ2] reaction of oxirane with olefin.
As a continuous investigation, we report in this paper an effi-
cient synthesis of spiro[furan-20,3-indolin]-2-ones (3) by the TPT-
catalyzed [3þ2] reactions of spiro[indoline-3,20-oxiran]-2-ones (1)
with electron-rich olefins (2) via TPT-sensitized CbeO bond cleav-
age of spiro-oxiranes and subsequent [3þ2] reactions with olefins
(Scheme 4).
Ph
H
O
CH3
O
O
hv
H
Ph
CH3
CH3
O
CH3
CH3
O
TPT
CH3
O
+
+
CH2Cl2
Ph
N
N
N
CH3
CH3
3a
Scheme 5. TPT-catalyzed [3þ2] reaction of 1a with 2a.
CH3
4a
2a
1a
R6
R7
R7
R5
R6
R5
R3
R4
O
hv
O
O
R3
R4
O
But in the case of other sensitizers, such as DCA, DCN, and
chloranil, the reaction was much slow and the products were
complex. If the deaerated anhydrous CH2Cl2 solution of 1a and 2a
R3
R4
R 6
R7
R1
TPT
R1
R1
+
+
CH2Cl2
O
O
R5
N
R2
N
R2
N
R2
was irradiated at
l
ꢀ350 nm in the absence of TPT for long time
(48 h), no products were detected. Thus, the TPT as catalyst was not
only more superior than other sensitizers but also necessary.
Therefore TPT was selected as the sensitizer in the [3þ2] reactions
of spiro[indoline-3,20-oxiran]-2-ones with olefins.
4
1
3
2
Scheme 4. TPT-catalyzed [3þ2] reactions of spiro[indoline-3,20-oxiran]-2-ones (1)
with olefins.
The photoreactions of 30,30-dimethylspiro[indoline-3,20-oxiran]-
2-ones (1aeg) with olefins (2aed) were examined under the same
conditions and the results were listed in Table 1. It could be found
that the products obtained were only one stereoisomer in most
cases, but for several reactions, such as 1a or 1c with 2a; 1d with 2b,
two stereoisomers were produced in different ratio. The two ste-
reoisomers were easily separated by repeated thin plate chroma-
tography. All these products 3aer and 4a, 4c, 4p were characterized
by 1H, 13C NMR spectroscopy, HRMS, and IR. The configurations of
representative products 3a, 4a, 3j, 3p, 4p, and 3r were determined
by NOESY as depicted in Fig. 1. The reciprocal interaction of H-5 and
H-40 was observed in 3a in accord with the cis configuration of 5-
phenyl group and 30-carbonyl group in products 3a; in contrast,
no reciprocal interaction of H-5 and H-40 was observed in 4a in
accord with the trans configuration of 5-phenyl group and 30-car-
bonyl group in products 4a. The reciprocal interactions of H-4 and
H-5 with H-40 were observed in 3j in accord with the cis configu-
ration of 5-phenyl group and 30-carbonyl group in products 3j. The
reciprocal interaction of hydrogen atom in 5-methyl group and H-40
was observed in 3p in accord with the cis configuration of 5-phenyl
group and 30-carbonyl group in products 3p in contrast, no
The heterocyclic spiro-oxindole framework is an important
structural motif in biologically relevant compounds as natural prod-
ucts and pharmaceuticals.7 3-Azaspiro-oxindole derivatives are well-
known and a number of synthetic methods have been developed for
expedition of these structural frameworks.8 3-oxaspiro-oxindoles
also possess some important biological activities. For example, Ia,b
are used for progesterone receptor antagonists;9a Ic are used for
treatinghypertension of mammals;9b IIa,b are usedfor treatment and
prevention of hypercholesterolemia, benign prostatic hyperplasia,
pruritis, and cancer.9c but the reports for the preparation of the cor-
responding 3-oxaspiro-oxindole analogues are rare.9,10 For example,
Almendros recently reported the synthesis of dihydrospiro[furan-
20,3-indole]-2-ones by ruthenium, silver, and palladium-catalyzed
carbonyl-addition/cyclization reaction of 2-indolinone-tethered
homoallylic alcohols;10a Alcaide reported the synthesis of spiro[fu-
ran-30,3-indole]-2-ones by indium-mediated Barbier-type carbonyl-
allenylation reaction from isatin to give 3-hydroxy-3-allenyl-2-
indolinones and subsequent palladium-catalyzed spirocyclization
by
a
-allenols-cross coupling reaction;10b Ganguly reported the syn-
thesis of spiro[furan-30,3-indole]-2-ones by radical cyclization of N-

L. Wang et al. / Tetrahedron 68 (2012) 1483e1491
1485
Table 1
Photochemical [3þ2] reactions of oxiranes 1aef with 2aeda
R3
R4
R3
R4
R2
O
CH3
O
O
hv
R4
R3
CH3
CH3
O
CH3
CH3
O
R2
X
TPT
CH3
O
X
X
+
+
CH2Cl2
R2
N
R1
N
R1
N
R1
4a,c,p
1a-f
3a-r
2a-d
b
Entry
Substrate
t (hr)
Convn. (%)
Product
Yieldc (3/4) (%)
R1
X
R2
R3
R4
1
2
3
4
5
6
7
8
1a
1b
1c
1a
1b
1c
1a
1b
1c
1a
1b
1c
1d
1e
1f
H
CH3
Ph
H
CH3
Ph
H
CH3
Ph
H
CH3
Ph
CH3
CH3
CH3
CH3
CH3
CH3
CH3
H
H
H
H
H
H
H
H
H
H
H
H
Br
CH3
OCH3
Br
NO2
CH3
Br
2a
2a
2a
2b
2b
2b
2c
2c
2c
2d
2d
2d
2a
2b
2a
2b
2a
2d
2d
H
H
H
H
H
H
H
H
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
H
H
H
CH3
CH3
CH3
Ph
Ph
Ph
H
H
H
H
CH3
CH3
CH3
CH3
H
10
10
5
8
8
90
95
100
79
93
100
81
93
100
82
93
95
68
93
90
78
12
95
75
3a, 4a
3b
3c, 4c
3d
3e
3f
3g
3h
3i
3j
3k
3l
3m
3n
3o
79 (8:1)
93
97 (6:1)
90
94
96
89
82
95
92
90
88
75
89
85
96 (8:1)
d
5
15
10
10
15
15
15
10
8
8
8
36
15
15
9
H
10
11
12
13
14
15
16
17
18
19
C6H4CH2
C6H4CH2
C6H4CH2
H
H
H
H
H
Ph
Ph
Ph
Ph
Ph
1d
1g
1f
3p, 4p
d
C6H4CH2
C6H4CH2
3q
3r
93
91
1d
H
a
Compound 1a (95 mg, 0.5 mmol), 2a (78 mg, 0.75 mmol), and TPT (10 mg) were dissolved in 20 ml dry dichloromethane in a 25 ml reaction flask. The solution was
ꢀ350 nm with a medium-pressure mercury lamp (500 W) at ambient temperature.
Conversion was calculated on the basis of substrate 1aef.
deaerated by bubbling Ar for 30 min and then irradiated at
l
b
c
Yield of isolated products was based on consumed substrates 1aef.
the electron-withdrawing groups X at 50 position of indole ring,
such as bromine atom in 1d retard the photoreaction (entry 13, 16,
and 19) and the nitro group in 1g restrains the photoreaction at all
(entry 17); but the electron-donating groups, such as methyl and
methoxy groups in 1e,f seemly have no great influence to the
photoreactions (entry 14 and 15).
Then, we examined the photoreactions of oxiranes bearing an
electron-withdrawing group, such as ethyl spiro[2-oxo-indoline-
3,20-oxiran]-30-carboxylate (1h) and 30-phenylspiro[indoline-3,20-
oxiran]-2-ones (1i), with olefins under the same conditions. Similar
results were obtained for the reactions of 30,30-dimethylspiro
[indoline-3,20-oxiran]-2-one (1h,i) (Table 2), and the obtained 3-
Fig. 1. NOESY correlations of 3a, 4a, 3j, 3p, 4p, and 3r.
reciprocal interaction of H-40 with hydrogen atom in 5-methyl
group were observed in 4p. The NOESY correlations of 3r was
similar to that of 3j and the structure of 3r was also determined by
the X-ray crystallography (Fig. 2),11 which was consistent to the
structure of 3r determined by NOESY.
It should be noticed that the substituents on the oxoindole ring
have some influences to the photoreaction efficiency of spiro
[indoline-3,20-oxiran]-2-ones. In comparison of the conversion of
1aec in photoreactions with 2aed, the reaction rates of 1a (R1¼H),
1b (R1¼Me), and 1c (R1¼Ph) increase gradually. The photoreactions
of 1c with 2aec are nearly quantitative in shorter reaction time, but
1a and 1b need more time to complete the reactions. In addition,
Fig. 2. X-ray crystal structure of 3r.

1486
L. Wang et al. / Tetrahedron 68 (2012) 1483e1491
Table 2
In order to synthesize dispiro-oxoindole compounds by the
Photochemical [3þ2] reactions of oxiranes 1h,i with 2a,da
established TPT-sensitized [3þ2] reactions, two dispiro-oxiranes
(1jek) were prepared and the TPT-sensitized photoreactions with
olefins (2aed) were carried out under the same conditions. The
obtained dispiro oxoindoles 5aeh were also derived from TPT-
sensitized CbeO bond cleavage of oxiranes and subsequent [3þ2]
cycloaddition with olefins from the elucidation of their 1H, 13C NMR
spectroscopy, and HRMS (Table 3). The configurations of represen-
tative products 5a, 6a, and 5h were determined by NOESY (Fig. 4).
R4
R4
R3
R3
R2
O
O
O
hv
R4
R3
R1
O
R2
R1
O
R1
O
TPT
+
+
CH2Cl2
R2
N
N
N
CH3
CH3
3r-v
CH3
1h-i
2a-d
4r
b
Entry Substrate
R1
t (hr) Convn. (%) Product Yieldc (3/4) (%)
Table 3
R2 R3 R4
Photochemical [3þ2] reactions of oxiranes 1j,k with 2aeda
R5
R4
1
2
3
4
5
1h COOEt 2b H Ph CH3 15
1h COOEt 2c Ph Ph 15
1h COOEt 2d C6H4CH2 15
2a H Ph CH3 15
2d C6H4CH2 15
95
85
82
79
60
3s, 4s 93 (6:1)
R4
R3
R5
R3
H
3t
89
81
92
90
hv
O
O
O
R5
R4
n
H
3u
3v
3w
TPT
n
n
+
+
1i Ph
1i Ph
O
CH2Cl2
R3
O
O
H
N
N
N
a
CH3
Compound 1h (124 mg, 0.5 mmol), 2b (89 mg, 0.75 mmol), and TPT (10 mg)
CH3
CH3
were dissolved in 20 ml dry dichloromethane in a 25 ml reaction flask. The solution
was deaerated by bubbling Ar for 30 min and then irradiated at
1j-k
2a-d
5a-h
6a, 6e
l
ꢀ350 nm with
a medium-pressure mercury lamp (500 W) at ambient temperature.
b
Entry Substrate
t (hr) Convn. (%) Product Yieldc (5/6) (%)
b
Conversion was calculated on the basis of substrate 1h,i.
Yield of isolated products was based on consumed substrates 1h,i.
c
n
R3 R4 R5
1
2
3
4
5
6
7
8
1j
1j
1j
1j
1k
1k
1k
1k
1
1
1
1
2
2
2
2
2a
2b
2c
H
H
H
Ph
H
10
95
94
93
77
100
99
5a, 6a 88 (5:1)
Ph CH3 10
Ph Ph 15
5b
94
oxaspiro-oxindoles (3sew) were also derived from TPT-sensitized
CbeO bond cleavage of oxiranes and subsequent [3þ2] reactions
with olefins from the elucidation of 1H, 13C NMR spectroscopy and
HRMS of all these products. The configurations of representative
product 3s, 4s, and 3v were determined by NOESY correlations and
by the comparison with the NOESY correlations of substrates 1h,i. It
was found that the configurations of two substrates 1h,i were dif-
ferent: no NOESY correlation was observed between H-2 and H-40 in
1h, but the NOESY correlation could be observed between H-2 and
H-40 in 1i. On the other hand, it could be inferred that the configu-
rations of C-2 in products 3sew were the same as those in the 1h,i
because only CbeO bond cleavage in photoreaction and the config-
uration of C-2 had no change. Therefore, the configuration of 3s and
4s could be assigned by the reciprocal interaction of hydrogen atom
in 5-methyl group with H-40 as well as with H-2; the configuration of
3v was assigned by the reciprocal interaction of hydrogen atom in 5-
methyl group with H-2 and H-40 as shown in Fig. 3.
5c
69
2d C6H4CH2
H
H
15
8
5
5d
64
2a
2b
2c
H
H
H
Ph
Ph CH3
Ph Ph 10
15
5e, 6e
5f
92 (6:1)
82
98
95
5g
91
2d C6H4CH2
H
5h
86
a
Compound 1j (115 mg, 0.5 mmol), 2a (78 mg, 0.75 mmol), and TPT (10 mg) were
dissolved in 20 ml dry dichloromethane in a 25 ml reaction flask. The solution was
deaerated by bubbling Ar for 30 min and then irradiated at
lꢀ350 nm with a me-
dium-pressure mercury lamp (500 W) at ambient temperature.
b
Conversion was calculated on the basis of substrate 1j,k.
Yield of isolated products was based on consumed substrates 1j,k.
c
Fig. 4. NOESY correlations of the 5a, 6a, and 5h.
It is found from Table 3 that the photoreaction efficiency of 1h,i
with olefins 2aed is much similar to that of 1b in Table 1. The re-
actions of 1h,i with 2a,b are relatively easier than those with 2c,d.
The NOESY correlations of products 5a, 6a, and 5h are also similar
to those of 3a, 4a, and 3j, thus the configurations of products 5a, 6a,
and 5h are also similar to those of 3a, 4a, and 3j.
Since no reaction ever took place in the dark or in the absence of
TPT with prolonged irradiation under the same conditions, the pho-
toreaction of 1 and 2 might be rationalized as a PET-catalyzed non-
synchronous cation radical [3þ2] reaction, similarly to the DCN-sen-
sitized [3þ2] reactions of stilbene oxides2 (Scheme 1). The photore-
actions were first initiated by the photoinduced electron transfer from
substrates 1aef and 1hek to excited TPT could be confirmed by the
Fig. 3. NOESY correlations of the 1h,i and 3s, 4s, 3v.
free energy change of electron transfer,
DG, calculated by the
ox
It could be noticed from the Table 2 that the photoreactions of
1h,i turn slow when two methyl groups in 1aef are replaced by
ethoxycarbonyl group (1h) or phenyl group (1i). Much more time is
needed to reach higher conversions, or the conversions decrease in
the same irradiation time.
RehmeWeller equation (
D
GET¼E (D)ꢁEr1e/d2 (A)ꢁ
D
EexcitþEcoul12). The
1/2
oxidative potentials of 1aek were determined by cyclic voltammetry
red
ꢂ
technique, the reduction potential of excited TPT (ETPT*/TPTꢁ ¼E1/
redþ
D
Eexcit) was 2.0 V versus SCE1d and the Ecoul in dichloromethane
Gs calculated were listed in Table 4.
2
was 0.13 V. The
D

L. Wang et al. / Tetrahedron 68 (2012) 1483e1491
1487
Table 4
The GET of the photoinduced electron transfer (PET) between TPT and oxiranes
1aek
4.2. General procedure for the photoreaction
D
Spiro[indoline-3,20-oxiran]-2-one (1a) (95 mg, 0.5 mmol) and
styrene (2a) (78 mg, 0.75 mmol) were dissolved in 50 ml anhydrous
dichloromethane in a 50 ml reaction flask. The solution was dea-
erated by bubbling Ar for 30 min and then TPT (10 mg, 0.025 mmol)
Entry
Substrate
Eopx (V)a versus SCE
DGET (V) versus SCE
X
1
2
3
4
5
6
7
8
1a
1b
1c
1d
1e
1f
1g
1h
1i
H
H
H
Br
CH3
OCH3
NO2
H
H
H
1.65
1.60
1.73
1.78
1.61
1.38
2.12
1.73
1.75
1.70
1.72
ꢁ0.23
ꢁ0.27
ꢁ0.14
ꢁ0.09
ꢁ0.26
ꢁ0.49
0.25
ꢁ0.14
ꢁ0.12
ꢁ0.17
ꢁ0.15
was added. The solution was irradiated at
lꢀ350 nm with a me-
dium-pressure mercury lamp (500 W) at ambient temperature
until the complete conversion of the starting material. The progress
of reaction was monitored by TLC at regular intervals. After the
solvent was removed under reduced pressure, the residue was
separated by column chromatography on silica gel eluted by hex-
ane/acetone 20:1 (v/v) to afford product 3a and 4a. The two ste-
reoisomers were further separated by preparative thin layer
chromatography and purified by recrystalization to give pure 3a
and 4a.
9
10
11
1j
1k
H
a
The oxidation potentials were measured by cyclic voltammetry using a 4 mm
diameter glassy carbon disk electrode as working electrode, a platinum tab as the
counter electrode, and a saturated calomel electrode as the reference electrode in
acetonitrile containing 0.1 M tetrabutylammonium hexafluorophosphate.
4.2.1. 2,3-Dimethyl-5-phenyl-4,5-dihydro-2H-spiro[furan-3,30-in-
dolin]-20-one (3a). Pale yellow solid; mp: 156e157 ꢃC; IR (KBr):
3251 (b), 3061, 3028, 2973, 2926, 1710 (s), 1618, 1470 (m), 1381,
1332 cmꢁ1 1H NMR (400 MHz, CDCl3)
; d ppm 8.43 (s, 1H), 7.47 (d,
Itcould be observed that the PET betweenTPTand 1aef and 1hek
are thermodynamically feasible because
1g. In comparison of the reactivity of 1b and 1eeg (entry 5 and 14e17
inTable 1) with the corresponding values of GET, it can be found that
the electron-withdrawing group Br atom and NO2 at 50 position of
oxoindole ring make the GET for PET between TPT and 1d and 1g
increase as compared with the GET between TPT and 1b, and the
reactivity of 1d and 1g with 2b decease (entry 16 and 17 inTable 1). In
fact, NO2 lead the GET for PET between TPT and 1g become positive
and no reaction took place. Differently, the electron-donating group,
such as methyl and methoxy groups in 1e,f make GET for PET be-
tweenTPTand 1e or 1d decrease, but the reactivityof 1e,f with 2b has
no great change (entry 14 and 15 in Table 1) as compared with that of
1b. On the other hand, since the oxidation potentials of 2aed
(1.67e1.83 V vs SCE13) were close to those of 1aed, the electron
transfer between excited TPT and 2aed was also possible. However,
the cyclodimerization of 2aed catalyzed by TPT was very slow in
comparison with the photoreactions of 1aef with 2aed under the
same conditions. Thus it could be inferred that the great negative
DGs are negative except for
J¼7.6 Hz, 2H), 7.38 (t, J¼7.6 Hz, 2H), 7.29 (d, J¼6.8 Hz, 1H), 7.20 (d,
J¼7.6 Hz, 2H), 6.99e6.93 (m, 1H), 6.90 (d, J¼8.4 Hz, 1H), 5.72 (t,
J¼8.4 Hz, 1H), 2.91 (dd, J¼12.8, 7.2 Hz, 1H), 2.46 (dd, J¼12.8, 8.4 Hz,
D
1H), 1.42 (s, 3H), 1.33 (s, 3H); 13C NMR (400 MHz, CDCl3)
d ppm
D
180.05, 143.17, 140.84, 130.15, 128.38, 128.38, 128.19, 127.11, 126.09,
125.44, 125.44, 122.10, 109.56, 84.78, 77.54, 61.29, 44.22, 27.34,
23.92; ESI-HRMS: m/z calcd for C19H19NO2þHþ: 294.1489, found
294.1493.
D
D
4.2.2. 2,2-Dimethyl-5-diphenyl-4,5-dihydro-2H-spiro[furan-3,30-in-
dolin]-20-one (4a). Yellow grease; IR (KBr): 3255 (b,) 3061, 3028,
D
2971, 2927, 1709 (s), 1620 (m), 1470 (m), 1363 (m), 1336 (m) cmꢁ1
;
1H NMR (400 MHz, CDCl3) d ppm 8.58 (s, 1H), 7.56 (d, J¼7.6 Hz, 2H),
7.42 (d, J¼7.6 Hz,1H), 7.39e7.35 (m, 2H), 7.30e7.22 (m, 2H), 7.08 (dt,
J¼7.6, 0.8 Hz, 1H), 6.90 (d, J¼7.6 Hz, 1H), 5.48 (t, J¼8.0 Hz, 1H), 2.77
(dd, J¼12.8, 8.8 Hz, 1H), 2.67e2.62 (m, 1H), 1.47 (s, 3H), 1.21 (s, 3H);
13C NMR (400 MHz, CDCl3)
d ppm 179.40, 142.83, 140.50, 131.38,
128.35,128.35,128.14, 127.35, 126.08, 126.08, 125.24,122.25, 109.73,
85.36, 78.42, 61.04, 44.71, 25.87, 25.02; ESI-HRMS: m/z calcd for
C19H19NO2þHþ: 294.1489, found 294.1491.
values of DGET do not correlate to great reactivity of substrates.
3. Conclusion
4.2.3. 10,2,2-Trimethyl-5-phenyl-4,5-dihydro-2H-spiro[furan-3,30-in-
dolin]-20-one (3b). Yellow grease; IR (KBr): 3058, 3027, 2976, 2934,
1712 (s), 1610 (s), 1493 (m), 1469 (m), 1374 (m), 1350 (m) cmꢁ1; 1H
In conclusion, an efficient photochemical approach to the syn-
thesis of spiro[furan-20,3-indolin]-2-ones and dispiro[cycloalkane-
1,20-furan-30,300-indolin]-200-ones in high yields and stereo-
selectivity has been established by 2,4,6-triphenylpyrylium tetra-
fluoroborate (TPT) catalyzed [3þ2] reaction of spiro[indoline-3,20-
oxiran]-2-one with olefins under mild conditions in this work.
NMR (400 MHz, CDCl3)
d
ppm 7.56 (d, J¼7.6 Hz, 2H), 7.44 (d,
J¼7.6 Hz, 1H), 7.36 (t, J¼7.6 Hz, 2H), 7.33e7.24 (m, 2H), 7.10 (t,
J¼7.6 Hz, 1H), 6.85 (d, J¼7.6 Hz, 1H), 5.47 (t, J¼8.4 Hz, 1H), 3.21 (s,
3H), 2.74 (dd, J¼13.2, 9.2 Hz, 1H), 2.60 (dd, J¼13.2, 8.0 Hz, 1H), 1.42
(s, 3H),1.17 (s, 3H); 13C NMR (400 MHz, CDCl3)
d ppm 176.91,143.29,
4. Experimental section
142.87, 130.79, 128.29, 128.29, 128.10, 127.25, 125.98, 125.98, 124.80,
122.21, 107.93, 85.22, 78.31, 60.53, 44.62, 26.28, 25.75, 24.97; ESI-
HRMS: m/z calcd for C20H21NO2þHþ: 308.1645, found 308.1642.
4.1. Experimental protocols
All reagents were purchased from commercial suppliers and
used without further purification. Flash chromatography was car-
ried out with silica gel (200e300 mesh). Analytical TLC was per-
formed with silica gel GF254 plates, and the products were
visualized by UV detection. 1H NMR and 13C NMR (300 or 400 MHz
and 75 or 100 MHz, respectively) spectra were recorded in CDCl3.
4.2.4. 2,2-Dimethyl-10,5-diphenyl-4,5-dihydro-2H-spiro[furan-3,30-
indolin]-20-one (3c). Yellow grease; IR (KBr): 3056, 3027, 2945,
2859, 1710 (s), 1610 (m), 1492 (m), 1458 (m), 1373 (m), 1352 (m)
cmꢁ1 1H NMR (400 MHz, CDCl3)
; d ppm 7.55e7.48 (m, 4H),
7.43e7.37 (m, 5H), 7.31e7.25 (m, 2H), 7.19 (t, J¼7.6 Hz, 1H), 7.03 (t,
J¼7.2 Hz, 1H), 6.80 (d, J¼8.0 Hz, 1H), 5.77 (t, J¼8.0 Hz, 1H), 3.00 (dd,
J¼12.8, 7.2 Hz, 1H), 2.53 (dd, J¼12.8, 8.8 Hz, 1H), 1.47 (s, 3H), 1.37 (s,
Chemical shifts (d) are reported in parts per million using TMS as
internal standard and spinespin coupling constants (J) are given in
hertz. The high resolution mass spectra (HRMS) were measured on
a Bruker Daltonics APEXII47e spectrometer by ESI. The substrates
1aeg and 5a,b were prepared according to the reported
procedures.14
3H); 13C NMR (400 MHz, CDCl3)
d ppm 177.36, 143.63, 143.15,
134.47, 129.61, 129.61, 129.55, 128.40, 128.40, 128.08, 128.08, 127.13,
126.68, 126.68, 125.48, 125.48, 125.35, 122.52, 109.13, 85.13, 77.73,
60.88, 44.42, 27.49, 23.97; ESI-HRMS: m/z calcd for C25H23NO2þHþ:
370.1802, found 370.1799.

1488
L. Wang et al. / Tetrahedron 68 (2012) 1483e1491
4.2.5. 2,2-Dimethyl-10,5-diphenyl-4,5-dihydro-2H-spiro[furan-3,30-
indolin]-20-one (4c). Yellow grease; IR (KBr): 3050, 3020, 2946,
2857, 1711 (s), 1608 (m), 1495 (m), 1452 (m), 1368 (m), 1357 (m)
6.78e6.70 (m, 3H), 3.68 (d, J¼12.8 Hz, 1H), 3.25 (d, J¼13.2 Hz, 1H),
1.28 (s, 3H), 1.02 (s, 3H); 13C NMR (400 MHz, CDCl3)
ppm 176.46,
150.49, 148.87, 142.98, 131.51, 128.15, 128.15, 127.98, 127.98, 127.65,
126.27, 126.10, 125.75, 125.08, 125.08, 124.90, 124.90, 122.00, 107.55,
86.03, 85.91, 61.31, 49.41, 26.43, 26.33, 25.55; ESI-HRMS: m/z calcd
for C26H25NO2þHþ: 384.1958, found 384.1955.
d
cmꢁ1; 1H NMR (400 MHz, CDCl3)
d
ppm 7.61 (d, J¼7.2 Hz, 2H), 7.52
(t, J¼8.4 Hz,), 7.42e7.34 (m, 5H), 7.29e7.21 (m, 2H), 7.13 (t, J¼7.6 Hz,
1H), 6.84 (d, J¼8.0 Hz, 1H), 5.50 (t, J¼8.0 Hz, 1H), 2.80 (m, 2H), 1.49
(s, 3H), 1.30 (s, 3H); 13C NMR (400 MHz, CDCl3)
d ppm 176.90,
143.46, 142.68,134.54, 130.32, 129.61, 129.61, 128.35, 128.35, 128.08,
128.06,127.38,126.69,126.69,126.30,126.30,125.14,122.64,109.28,
85.73, 78.38, 60.72, 44.65, 25.40, 25.06; ESI-HRMS: m/z calcd for
C25H23NO2þHþ: 370.1802, found 370.1804.
4.2.11. 2,2-Dimethyl-10,5,5-triphenyl-4,5-dihydro-2H-spiro[furan-
3,30-indolin]-20-one (3i). Yellow grease; IR (KBr): 3045, 3031, 2925
(m), 2868, 1756 (s), 1609 (m), 1478, 1460 (m), 1372 (m), 1350 (m)
cmꢁ1; 1H NMR (400 MHz, CDCl3)
d
ppm 7.63 (t, J¼9.2 Hz, 4H), 7.48
(dd, J¼8.4, 6.8 Hz, 2H), 7.38e7.34 (m, 3H), 7.31e7.21 (m, 4H), 7.14 (t,
J¼7.6 Hz, 1H), 7.10e7.05 (m, 2H), 6.80e6.73 (m, 3H), 3.78 (d,
J¼13.2 Hz, 1H), 3.40 (d, J¼13.2 Hz, 1H), 1.34 (s, 3H), 1.11 (s, 3H); 13C
4.2.6. 2,2,5,-Trimethyl-5-phenyl-4,5-dihydro-2H-spiro[furan-3,30-in-
dolin]-20-one (3d). Pale yellow solid; mp: 236e238 ꢃC; IR (KBr):
3285 (b), 3032, 2968, 2917, 1712 (s), 1608, 1457 (m), 1371,
NMR (400 MHz, CDCl3) d ppm 175.92, 150.34, 148.92, 142.95, 134.61,
1338 cmꢁ1
;
1H NMR (400 MHz, CDCl3)
d
ppm 7.96 (s, 1H), 7.62 (d,
131.21, 129.52, 129.52, 128.19, 128.19, 128.00, 128.00, 127.96, 127.57,
126.69, 126.69, 126.34, 126.13, 126.01, 125.15, 125.15, 124.95, 124.95,
122.43, 108.85, 86.32, 86.20, 61.49, 49.48, 26.36, 25.80; ESI-HRMS:
m/z calcd for C31H27NO2þHþ: 446.2115, found 446.2117.
J¼7.2 Hz, 1H), 7.48 (d, J¼7.6 Hz, 2H), 7.34 (t, J¼7.6 Hz, 2H), 7.24e7.21
(m, 2H), 7.08 (t, J¼7.6 Hz, 1H), 6.86 (d, J¼8.0 Hz, 1H), 3.35 (d,
J¼13.2 Hz, 1H), 2.64 (d, J¼12.8 Hz, 1H), 1.72 (s, 3H), 1.16 (s, 3H), 1.09
(s, 3H); 13C NMR (400 MHz, CDCl3)
d ppm 178.42, 151.26, 140.11,
132.68, 127.91, 127.87, 127.87, 126.17, 126.09, 124.74, 124.74, 122.12,
109.58, 86.04, 83.15, 61.80, 50.01, 34.21, 26.46, 25.66; ESI-HRMS: m/
z calcd for C20H21NO2þHþ: 308.1645, found 308.1648.
4.2.12. 2,2-Dimethyl-2,3a,4,8b-tetrahydrospiro[indeno[1,2-b]furan-
3,30-indolin]-20-one (3j). Pale yellow solid; mp: 223e225 ꢃC; IR
(KBr): 3052, 3023, 2925 (m), 2855, 1710 (s), 1609 (m), 1478 (m),
1454 (m), 1368 (m), 1352 (m) cmꢁ1 1H NMR (400 MHz, CDCl3)
;
4.2.7. l0,2,2,5-Tetramethyl-5-phenyl-4,5-dihydro-2H-spiro[furan-
3,30-indolin]-20-one (3e). Pale yellow solid; mp: 124e126 ꢃC; IR
(KBr): 3056, 2976, 2931, 1713 (s), 1610 (m), 1492 (m), 1469 (m), 1373
d
ppm 7.76 (s, 1H), 7.54 (t, J¼4.4 Hz, 1H), 7.39 (d, J¼7.6 Hz, 1H),
7.31e7.17 (m, 4H), 7.08 (dt, J¼7.6, 1.2 Hz, 1H), 5.85 (d, J¼4.2 Hz, 1H),
3.64e3.58 (m, 1H), 3.39 (dd, J¼17.6, 3.2 Hz, 1H), 3.0 (dd, J¼17.2,
9.2 Hz, 1H), 1.31 (s, 3H), 1.16 (s, 3H); 13C NMR (400 MHz, CDCl3)
(m), 1347 (m) cmꢁ1 1H NMR (400 MHz, CDCl3)
; d ppm 7.64 (d,
J¼7.6 Hz, 1H), 7.47 (d, J¼7.6 Hz, 2H), 7.35e7.29 (m, 3H), 7.20 (t,
J¼7.2 Hz, 1H), 7.11 (t, J¼7.6 Hz, 1H), 6.85 (d, J¼7.6 Hz, 1H), 3.33 (d,
J¼12.8 Hz, 1H), 3.18 (s, 3H), 2.60 (d, J¼13.2 Hz, 1H), 1.71 (s, 3H), 1.15
d ppm 177.17, 143.40, 141.98, 140.44, 131.23, 128.64, 128.13, 127.00,
125.43, 124.97, 124.44, 122.25, 109.30, 86.43, 86.01, 64.01, 51.24,
33.25, 25.01, 24.34; ESI-HRMS: m/z calcd for C20H19NO2þHþ:
306.3777, found 306.3774.
(s, 3H),1.07 (s, 3H); 13C NMR (400 MHz, CDCl3)
d ppm 176.36,151.24,
143.16, 132.11, 127.89, 127.83, 127.83, 126.12, 125.64, 124.68, 124.68,
122.05, 107.93, 85.90, 83.02, 61.37, 50.02, 34.16, 26.40, 26.38, 25.67;
ESI-HRMS: m/z calcd for C21H23NO2þHþ:322.1802, found 322.1806.
4.2.13. 10,2,2-Trimethyl-2,3a,4,8b-tetrahydrospiro[indeno[1,2-b]fu-
ran-3,30-indolin]-20-one (3k). Pale yellow solid; mp: 135e136 ꢃC; IR
(KBr): 3050, 3021, 2927 (m), 2857, 1708 (s), 1609 (s), 1490 (m), 1468
4.2.8. 2,2,5-Trimethyl-l0,5-diphenyl-4,5-dihydro-2H-spiro[furan-3,30-
indolin]-20-one (3f). Pale yellow solid; mp: 176e178 ꢃC; IR (KBr):
3058, 3023, 2953, 2857, 1712 (s), 1605, 1486 (m), 1465, 1367 (m),
(m), 1374 (m), 1346 (m) cmꢁ1 1H NMR (400 MHz, CDCl3)
; d ppm
7.55e7.53 (m, 1H), 7.42 (d, J¼7.6 Hz, 1H), 7.34e7.27 (m, 3H), 7.20 (d,
J¼8.4 Hz, 1H), 7.11 (dt, J¼7.6, 0.8 Hz, 1H), 6.85 (d, J¼7.6 Hz, 1H), 5.87
(d, J¼8.0 Hz, 1H), 3.60e3.54 (m, 1H), 3.47 (dd, J¼17.6, 3.6 Hz, 1H),
3.19 (s, 3H), 2.96 (dd, J¼17.2, 10.0 Hz, 1H), 1.22 (s, 3H), 1.10 (s, 3H);
1348 (m) cmꢁ1; 1H NMR (400 MHz, CDCl3)
d
ppm 7.71 (d, J¼7.2 Hz,
1H), 7.51e7.47 (m, 4H), 7.40e7.31 (m, 5H), 7.25e7.21 (m, 2H), 7.13 (t,
J¼7.6 Hz, 1H), 6.82 (d, J¼7.6 Hz, 1H), 3.45 (d, J¼13.2 Hz, 1H), 2.74 (d,
J¼13.2 Hz, 1H), 1.76 (s, 3H), 1.20 (s, 3H), 1.17 (s, 3H); 13C NMR
13C NMR (400 MHz, CDCl3)
d ppm 175.23, 143.44, 143.24, 142.08,
131.10, 128.64, 128.06, 126.84, 125.38, 124.50, 124.42, 122.24, 107.70,
86.42, 86.14, 63.40, 50.92, 33.09, 26.05, 25.12, 24.41; ESI-HRMS: m/z
calcd for C21H21NO2þHþ: 320.1645, found 320.1648.
(400 MHz, CDCl3)
d ppm 175.85, 151.19, 143.18, 134.60, 131.91,
129.53, 129.53, 128.00, 127.89, 127.89, 127.82, 126.76, 126.76, 126.18,
125.96, 124.74, 124.74, 122.50, 109.25, 86.31, 83.21, 61.55, 50.21,
34.30, 26.50, 25.94; ESI-HRMS: m/z calcd for C26H25NO2þHþ:
384.1958, found 384.1955.
4.2.14. 2,2-Dimethyl-10-phexyl-2,3a,4,8b-tetrahydrospiro
[indeno
[1,2-b]furan-3,30-indolin]-20-one (3l). Pale yellow solid; mp: 161 ꢃC;
IR (KBr): 3048, 3025, 2932 (m), 2859, 1705 (s), 1608 (m), 1488 (m),
4.2.9. 2,2-Dimethyl-5,5-diphenyl-4,5-dihydro-2H-spiro[furan-3,30-
indolin]-20-one (3g). Pale yellow solid; mp: 265e266 ꢃC; IR (KBr):
3390 (b), 2917, 2847, 1778 (m), 1599 (s), 1501 (m), 1348 (m), 1159 (s)
1364 (m), 1376 (m), 1347 (m) cmꢁ1 1H NMR (400 MHz, CDCl3)
;
d
ppm 7.54e7.47 (m, 4H), 7.39e7.35 (m, 3H), 7.27e7.11 (m, 5H), 6.84
(d, J¼7.6 Hz, 1H), 5.91 (d, J¼8.0 Hz, 1H), 3.71e3.65 (m, 1H), 3.58 (dd,
cmꢁ1 1H NMR (400 MHz, CDCl3)
; d ppm 7.91 (s, 1H), 7.61 (d,
J¼17.6, 3.6 Hz, 1H), 3.04 (dd, J¼17.6, 10.4 Hz, 1H), 1.29 (s, 3H), 1.21 (s,
J¼8.0 Hz, 4H), 7.30e7.07 (m, 7H), 6.79 (d, J¼8.0 Hz, 1H), 6.72 (dt,
J¼7.6, 0.8 Hz,1H), 6.66 (d, J¼7.2 Hz,1H), 3.60 (d, J¼13.2 Hz, 1H), 3.28
(d, J¼13.2 Hz, 1H), 1.29 (s, 3H), 1.06 (s, 3H); 13C NMR (400 MHz,
3H);13C NMR (400 MHz, CDCl3)
d ppm 174.66,143.42,143.15,142.07,
134.51, 131.06, 129.48, 129.48, 128.69, 127.98, 127.89, 126.89, 126.69,
126.69, 125.41, 124.79, 124.61, 122.72, 109.07, 86.92, 86.35, 63.37,
51.25, 33.22, 25.26, 24.56; ESI-HRMS: m/z calcd for C26H23NO2þHþ:
382.1802, found 382.1805.
CDCl3)
d ppm 178.48, 150.48, 148.81, 139.89, 132.06, 128.20, 128.20,
128.01, 128.01, 127.67, 126.34, 126.21, 126.14, 125.10, 125.10, 124.95,
124.95, 122.06, 109.17, 86.14, 86.05, 61.73, 49.39, 26.39, 25.51; ESI-
HRMS: m/z calcd for C25H23NO2þHþ: 370.1802, found 370.1800.
4.2.15. 50-Bromo-10,2,2-trimethyl-5-phenyl-4,5-dihydro-2H-spiro[fu-
ran-3,30-indolin]-20-one (3m). Yellow grease; IR (KBr): 3065, 3025,
2968, 2925, 1712 (s), 1610, 1473 (m), 1453 (m), 1378, 1335 cmꢁ1; 1H
4.2.10. 10,2,2-Trimethyl-5,5-diphenyl-4,5-dihydro-2H-spiro[furan-
3,30-indolin]-20-one (3h). Pale yellow solid; mp: 160e162 ꢃC; IR
(KBr): 3037, 3028, 2935 (m), 2872, 1768 (s), 1605, 1482 (m), 1453
NMR (400 MHz, CDCl3)
d
ppm 7.45 (d, J¼7.2 Hz, 2H), 7.38 (t,
J¼7.2 Hz, 3H), 7.33 (d, J¼2.0 Hz, 1H), 7.28 (t, J¼7.2 Hz, 1H), 6.70 (d,
J¼8.4 Hz, 1H), 5.70 (t, J¼8.0 Hz, 1H), 3.21 (s, 3H), 2.89 (dd, J¼12.8,
7.6 Hz,1H), 2.38 (dd, J¼13.2, 8.8 Hz,1H), 1.37 (s, 3H), 1.28 (s, 3H); 13C
(m), 1368 (m), 1347 (m) cmꢁ1
;
1H NMR (400 MHz, CDCl3)
d
ppm
7.60 (d, J¼8.0 Hz, 4H), 7.29e7.24 (m, 4H), 7.18e7.10 (m, 3H),

L. Wang et al. / Tetrahedron 68 (2012) 1483e1491
1489
NMR (400 MHz, CDCl3)
d
ppm 177.24, 142.75, 142.68, 132.16, 130.98,
4.2.21. 50-Bromo-10,2,2-trimethyl-2,3a,4,8b-tetrahydrospiro [indeno
[1,2-b]furan-3,30-indolin]-20-one (3r). Pale yellow solid; mp:
223e224 ꢃC; IR (KBr): 3068, 3025, 2927, 1712 (s), 1607 (m), 1468
(m), 1462 (m), 1363 (m), 1341 (m) cmꢁ1; 1H NMR (400 MHz, CDCl3)
128.45, 128.45, 128.26, 127.25, 125.38, 125.38, 114.84, 109.19, 84.86,
77.43, 60.91, 44.36, 27.14, 26.32, 23.83; ESI-HRMS: m/z calcd for
C20H20BrNO2þHþ: 386.0750, found 386.0753.
d
ppm 7.53 (d, J¼1.6 Hz, 2H), 7.43 (dd, J¼8.0, 1.6 Hz, 1H), 7.28 (t,
4.2.16. 10,2,2,5,50-Pentamethyl-5-diphenyl-4,5-dihydro-2H-spiro[fu-
ran-3,30-indolin]-20-one (3n). Pale yellow solid; mp: 112 ꢃC; IR
(KBr): 3056, 2976, 2932, 1711 (s), 1606, 1497 (m), 1448, 1352 (m); 1H
J¼3.6 Hz, 2H), 7.19 (d, J¼7.6 Hz, 1H), 6.72 (d, J¼8.4 Hz, 1H), 5.86 (d,
J¼8.0 Hz, 1H), 3.54 (t, J¼3.6 Hz, 1H), 3.51e3.48 (m, 1H), 3.17 (s, 3H),
2.96 (dd, J¼18.4, 10.8 Hz, 1H), 1.19 (s, 3H), 1.08 (s, 3H); 13C NMR
NMR (400 MHz, CDCl3)
d
ppm 7.49e7.47 (m, 3H), 7.33 (t, J¼7.6 Hz,
(400 MHz, CDCl3) d ppm 174.62, 143.24, 142.22, 142.05, 133.59,
2H), 7.24e7.19 (m, 1H), 7.1 (dd, J¼8.0, 0.8 Hz, 1H), 6.73 (d, J¼8.0 Hz,
1H), 3.33 (d, J¼13.2 Hz,1H), 3.15 (s, 3H), 2.58 (d, J¼13.2 Hz, 1H), 2.39
(s, 3H), 1.72 (s, 3H), 1.14 (s, 3H), 1.07 (s, 3H); 13C NMR (400 MHz,
130.90, 128.79, 127.57, 126.98, 125.49, 124.56, 115.02, 109.13, 86.49,
86.29, 63.49, 51.16, 32.96, 26.21, 25.24, 24.55; ESI-HRMS: m/z calcd
for C21H20BrNO2þHþ: 398.0750, found 398.0747.
CDCl3)
d ppm 176.21, 151.28, 140.81, 132.17, 131.44, 128.07, 127.80,
127.80, 126.46, 126.08, 124.66, 124.66, 107.58, 85.86, 82.95, 61.41,
49.97, 34.18, 26.39, 25.65, 21.24; ESI-HRMS: m/z calcd for
C22H25NO2þHþ: 336.1958, found 336.1960.
4.2.22. Ethyl
[furan-3,30-indolin]-2-carboxylate
mp:119e121 ꢃC; IR (KBr): 3048, 3027, 2965, 2937,1753 (m),1710 (s),
1608 (s), 1457, 1436, 1368 (m), 1351 (m) cmꢁ1 1H NMR (400 MHz,
CDCl3)
10,5-dimethyl-20-oxo-5-phenyl-4,5-dihydro-2H-spiro
(3s). Pale yellow solid;
;
4.2.17. 50-Methoxy-10,2,2,5-tetramethyl-5-phenyl-4,5-dihydro-2H-
spiro[furan-3,30-indolin]-20-one (3o). Yellow grease; IR (KBr): 3053,
3022, 2926 (m), 2855, 1696 (s), 1601 (s), 1495 (m), 1468 (m), 1371
d
ppm 7.61 (d, J¼6.8 Hz, 2H), 7.39 (t, J¼7.2 Hz, 2H), 7.29 (d,
J¼7.2 Hz, 1H), 7.17 (dt, J¼7.6, 2.0 Hz, 1H), 6.78 (t, J¼8.0 Hz, 3H), 5.08
(s, 1H), 3.78e3.68 (m, 2H), 3.26 (s, 3H), 2.92 (d, J¼13.2 Hz, 1H), 2.76
(d, J¼12.8 Hz, 1H), 1.82 (s, 3H), 0.72 (t, J¼7.2 Hz, 3H); 13C NMR
(m), 1342 (m) cmꢁ1 1H NMR (400 MHz, CDCl3)
; d ppm 7.47 (d,
J¼8.4 Hz, 2H), 7.33 (t, J¼7.6 Hz, 2H), 7.29 (d, J¼2.4 Hz, 1H), 7.22 (t,
J¼7.2 Hz,1H), 6.84 (dd, J¼8.4, 2.4 Hz,1H), 6.75 (d, J¼8.4 Hz,1H), 3.83
(s, 3H), 3.34 (d, J¼13.2 Hz, 1H), 3.16 (s, 3H), 2.58 (d, J¼13.2 Hz, 1H),
1.72 (s, 3H), 1.14 (s, 3H), 1.08 (s, 3H); 13C NMR (400 MHz, CDCl3)
(400 MHz, CDCl3) d ppm 176.31, 167.89, 146.96, 143.25, 130.64,
128.30,128.30,128.26,126.81,124.59,124.59,124.40,122.73,107.54,
85.88, 82.92, 60.49, 58.02, 51.56, 30.47, 26.55, 13.49; ESI-HRMS: m/z
calcd for C22H23NO4þHþ: 366.1700, found 336.1702.
d
ppm 175.95, 155.56, 151.27, 136.77, 133.53, 127.85, 127.85, 126.15,
124.69, 124.69, 113.26, 112.19, 108.07, 85.90, 82.97, 61.80, 55.84,
50.05, 34.20, 26.52, 26.50, 25.54; ESI-HRMS: m/z calcd for
C22H25NO3þHþ: 352.1841, found 352.1844.
4.2.23. Ethyl
10,5-dimethyl-20-oxo-5-phenyl-4,5-dihydro-2H-spiro
[furan-3,30-indolin]-2-carboxylate (4s). Yellow grease; IR (KBr):
3046, 3028, 2968, 2942,1754 (m),1711 (s),1610 (s),1456,1436,1366
(m), 1355 (m) cmꢁ1 1H NMR (400 MHz, CDCl3)
; d ppm 7.51 (dd,
4.2.18. 50-Bromo-10,2,2,5-tetramethyl-5-phenyl-4,5-dihydro-2H-
spiro[furan-3,30-indolin]-20-one (3p). Yellow grease; IR (KBr):
3062, 2968, 2945, 1710 (s), 1610 (m), 1478 (m), 1449 (m), 1368
J¼13.6, 7.2 Hz, 3H), 7.38 (t, J¼7.6 Hz, 2H), 7.31e7.28 (m, 2H), 7.09 (t,
J¼6.8 Hz, 1H), 6.83 (d, J¼7.6 Hz, 1H), 4.74 (s, 1H), 3.83e3.66 (m, 2H),
3.20 (s, 3H), 3.19 (d, J¼13.2 Hz, 1H), 2.50 (d, J¼13.2 Hz, 1H), 1.82 (s,
(m), 1337 (m) cmꢁ1
;
1H NMR (400 MHz, CDCl3)
d
ppm 7.70
3H), 0.70 (t, J¼6.8 Hz, 3H); 13C NMR (400 MHz, CDCl3)
d ppm 175.96,
(d, J¼1.6 Hz, 1H), 7.47e7.42 (m, 3H), 7.33 (t, J¼7.2 Hz, 2H), 7.23
(d, J¼7.2 Hz, 1H), 6.72 (d, J¼8.4 Hz, 1H), 3.33 (d, J¼13.2 Hz, 1H),
3.16 (s, 3H), 2.57 (d, J¼13.2 Hz, 1H), 1.70 (s, 3H), 1.13 (s, 3H), 1.07
167.51, 146.60, 143.42, 131.30, 128.62, 128.54, 128.54, 127.03, 124.66,
124.66,123.93,122.91,107.74, 85.77, 82.83, 60.51, 58.15, 50.81, 31.96,
26.44, 13.54; ESI-HRMS: m/z calcd for C22H23NO4þHþ: 366.1700,
found 336.1703.
(s, 3H); 13C NMR (400 MHz, CDCl3)
d ppm 175.74, 151.02, 142.23,
134.25, 130.76, 128.75, 127.92, 127.92, 126.27, 124.66, 124.66,
114.88, 109.31, 85.94, 83.09, 61.63, 49.97, 34.24, 26.52, 26.35,
25.62; ESI-HRMS: m/z calcd for C21H22BrNO2þHþ: 400.0907,
found 400.0909.
4.2.24. Ethyl
[furan-3,30-indoline]-2-carboxylate
mp:148e150 ꢃC; IR (KBr): 3057, 3024, 2969, 2926, 1757 (m), 1716
(s), 1610 (s), 1468, 1446, 1376 (m), 1353 (m) cmꢁ1 1H NMR
(400 MHz, CDCl3)
10-methyl-20-oxo-5,5-diphenyl-4,5-dihydro-2H-spiro
(3t). Pale yellow solid;
;
4.2.19. 50-Bromo-10,2,2,5-tetramethyl-5-phenyl-4,5-dihydro-2H-
spiro[furan-3,30-indolin]-20-one (4p). Pale yellow solid; mp:
164e166 ꢃC; IR (KBr): 3060, 2970, 2948, 1712 (s), 1608 (m), 1476
(m), 1446 (m), 1370 (m), 1342 (m) cmꢁ1; 1H NMR (400 MHz, CDCl3)
d
ppm 7.63 (dd, J¼10.8, 7.6 Hz, 4H), 7.33 (t,
J¼7.2 Hz, 4H), 7.25e7.17 (m, 3H), 6.83 (d, J¼4.0 Hz, 2H), 6.77 (d,
J¼7.6 Hz, 1H), 4.94 (s, 1H), 3.75e3.68 (m, 2H), 3.62 (d, J¼13.6 Hz,
1H), 3.22 (s, 3H), 2.96 (d, J¼13.2 Hz, 1H), 0.70 (t, J¼7.2 Hz, 3H); 13C
d
ppm 7.48 (d, J¼7.6 Hz, 2H), 7.38e7.32 (m. 3H), 7.28e7.24 (m, 1H),
NMR (400 MHz, CDCl3) d ppm 175.89, 167.50, 146.01, 145.68, 143.32,
6.97 (d, J¼2.0 Hz, 1H), 6.65 (d, J¼8.4 Hz, 1H), 3.19 (s, 3H), 2.90 (dd,
130.45, 128.41, 128.41, 128.39, 128.24, 128.24, 127.22, 126.92, 125.94,
125.94, 125.43, 125.43, 124.56, 122.71, 107.53, 88.99, 82.99, 60.42,
58.00, 50.20, 26.47, 13.48; ESI-HRMS: m/z calcd for C27H25NO4þHþ:
428.1857, found 428.1859.
J¼25.6, 13.2 Hz, 1H), 1.80 (s, 3H), 1.35 (s, 3H), 1.05 (s, 3H); 13C NMR
(400 MHz, CDCl3)
d ppm 177.50, 150.89, 142.80, 131.57, 130.86,
128.51, 128.09, 128.09, 126.41, 124.71, 124.71, 114.56, 109.01, 85.52,
83.68, 61.93, 48.76, 34.05, 27.24, 26.29, 25.16; ESI-HRMS: m/z calcd
for C21H22BrNO2þHþ: 400.0907, found 400.0904.
4.2.25. Ethyl 10-methyl-20-oxo-2,3a,4,8b-tetrahydrospiro [indeno
[1,2-b]furan-3,30-indoline]-2-carboxylate (3u). Pale yellow solid;
mp:154e156 ꢃC; IR (KBr): 3052, 3030, 2973, 2942, 1756 (m), 1711
4.2.20. 10,2,2,50-Tetramethyl-2,3a,4,8b-tetrahydrospiro [indeno[1,2-b]
furan-3,30-indolin]-20-one (3q). Yellow grease; IR (KBr): 3055, 3027,
2935 (m), 2853, 1708 (s), 1612 (m), 1465 (m), 1367 (m), 1336 (m)
(s), 1612 (s), 1465, 1462, 1374 (m), 1346 (m) cmꢁ1 1H NMR
;
(400 MHz, CDCl3)
d
ppm 7.59 (d, J¼6.8 Hz,1H), 7.47 (d, J¼7.2 Hz,1H),
cmꢁ1
;
1H NMR (400 MHz, CDCl3)
d
ppm 7.54e7.52 (m, 1H),
7.34e7.28 (m, 4H), 7.09 (t, J¼7.6 Hz, 1H), 6.85 (d, J¼8.0 Hz, 1H), 6.08
(d, J¼6.8 Hz, 1H), 4.68 (s, 1H), 4.06 (dd, J¼17.6, 4.8 Hz, 1H),
3.87e3.70 (m, 2H), 3.29e3.25 (m, 4H), 2.90 (dd, J¼17.2, 9.2 Hz, 1H),
7.29e7.18 (m, 4H), 7.10 (dd, J¼8.0, 0.8 Hz, 1H), 6.73 (d, J¼7.6 Hz, 1H),
5.87 (d, J¼8.0 Hz, 1H), 3.57e3.50 (m, 2H), 3.17 (s, 3H), 3.00e2.91 (m,
1H), 1.19 (s, 3H), 1.09 (s, 3H); 13C NMR (400 MHz, CDCl3)
d
ppm
0.73 (t, J¼7.2 Hz, 3H); 13C NMR (400 MHz, CDCl3)
d ppm 174.22,
175.20, 143.55, 142.30, 140.86, 131.78, 131.53, 128.68, 128.29, 126.87,
125.46, 125.29, 124.59, 107.42, 86.48, 86.29, 63.37, 51.13, 33.09,
26.14, 25.27, 24.63, 21.25; ESI-HRMS: m/z calcd for C22H23NO2þHþ:
334.1802, found 334.1800.
167.87, 143.80, 142.71, 139.51, 131.10, 129.58, 128.66, 127.09, 125.96,
124.68, 123.75, 123.02, 107.74, 88.68, 81.93, 60.65, 58.81, 52.26,
31.48, 26.52, 13.64; ESI-HRMS: m/z calcd for C22H21NO4þHþ:
364.1544, found 364.1546.

1490
L. Wang et al. / Tetrahedron 68 (2012) 1483e1491
4.2.26. l0,5-Dimethyl-2,5-diphenyl-4,5-dihydro-2H-spiro [furan-3,30-
indolin]-20-one (3v). Yellow grease; IR (KBr): 3051, 3021, 2971, 2910,
1711 (s), 1608 (m), 1487 (m), 1458 (m), 1371 (m), 1342 (m) cmꢁ1; 1H
4.2.31. 100-Methyl-50,50-phenyl-4,5-dihydro-2H-dispiro
[cyclo-
pentane-1,20-furan-30,300-indolin]-200-one (5c). Pale yellow solid;
mp: 193e194 ꢃC; IR (KBr): 3058, 3028, 2928 (m), 2856, 1712 (s),
1610 (m), 1488 (m), 1452 (m), 1371 (m), 1350 (m); 1H NMR
NMR (400 MHz, CDCl3)
d
ppm 7.65 (d, J¼8.0 Hz, 2H), 7.44 (t,
J¼7.6 Hz, 2H), 7.32 (t, J¼8.0 Hz, 1H), 7.16 (d, J¼7.2 Hz, 2H), 7.08e7.02
(m, 4H), 6.94 (dt, J¼7.6, 1.2 Hz, 1H), 6.34 (t, J¼7.6 Hz, 1H), 6.49 (d,
J¼8.0 Hz, 1H), 5.61 (s, 1H), 3.16 (s, 3H), 3.10 (d, J¼13.2 Hz, 1H), 2.74
(400 MHz, CDCl3)
d
ppm 7.60 (d, J¼8.0 Hz, 4H), 7.26 (dd, J¼15.2,
7.2 Hz, 4H), 7.17e7.11 (m, 3H), 6.75 (dd, J¼10.8, 7.6 Hz, 3H), 3.63 (d,
J¼12.8 Hz, 1H), 3.19 (s, 3H), 1.87e1.58 (m, 5H), 1.51e1.47 (m, 1H),
1.41e1.36 (m, 1H), 1.04e0.98 (m, 1H); 13C NMR (400 MHz, CDCl3)
(d, J¼12.8 Hz, 1H), 1.88 (s. 3H); 13C NMR (400 MHz, CDCl3)
d ppm
176.81, 148.12, 136.40, 130.95, 128.50, 128.32, 128.32, 127.70, 127.48,
127.48, 127.44, 126.96, 125.47, 125.47, 125.17, 124.69, 124.69, 122.07,
107.30, 85.95, 83.93, 61.14, 51.18, 31.49, 26.33; ESI-HRMS: m/z calcd
for C25H23NO2þHþ: 370.1802, found 370.1800.
d ppm 176.32, 150.51, 148.71, 142.85, 132.28, 128.14, 128.14, 128.01,
128.01, 127.55, 126.29, 126.19, 125.60, 125.14, 125.14, 124.92, 124.92,
122.08, 107.44, 96.68, 86.04, 59.92, 49.71, 35.46, 33.86, 26.47, 23.74,
22.79; ESI-HRMS: m/z calcd for C28H27NO2þHþ: 410.2115, found
410.2118.
4.2.27. 10-Methyl-2-phexyl-2,3a,4,8b-tetrahydrospiro [indeno[1,2-b]
furan-3,30-indolin]-20-one
(3w). Pale
yellow
solid;
mp:
4.2.32. 100-Methyl-4,5-dihydro-2H-dispiro[cyclopentane-1,20-indeno
[1,2-b]furan-30,300-indolin]-200-one (5d). Pale yellow solid; mp:
132e134 ꢃC; IR (KBr): 3051, 3025, 2926 (m), 2859, 1705 (s), 1609
(m), 1468 (m), 1374 (m), 1347 (m) cmꢁ1; 1H NMR (400 MHz, CDCl3)
195e196 ꢃC; IR (KBr): 3042, 3028, 2966 (m), 2859, 1715 (s), 1611
(m), 1465 (m), 1377 (m), 1337 (m) cmꢁ1; 1H NMR (400 MHz, CDCl3)
d
ppm 7.59 (d, J¼7.2 Hz, 1H), 7.50 (d, J¼7.6 Hz, 1H), 7.40e7.27 (m,
3H), 7.14 (dt, J¼8.0, 1.2 Hz, 1H), 7.12e6.98 (m, 6H), 6.59 (d,
J¼8.0 Hz, 1H), 6.13 (d, J¼6.8 Hz, 1H), 5.09 (s, 1H), 4.37 (dd, J¼17.6,
4.8 Hz, 1H), 3.45e3.40 (m, 1H), 2.97 (dd, J¼17.6, 10.0 Hz, 1H); 13C
d
ppm 7.55 (d, J¼7.2 Hz, 1H), 7.47 (d, J¼7.6 Hz,), 7.32e7.22 (m, 4H),
7.11 (t, J¼7.2 Hz, 1H), 6.86 (d, J¼7.6 Hz, 1H), 5.86 (d, J¼7.6 Hz, 1H),
4.06 (dd, J¼17.6, 4.8 Hz, 1H), 3.38e3.32 (m, 1H), 3.26e3.23 (m, 3H),
2.90 (dd, J¼17.6, 10.0 Hz, 1H), 2.01e1.94 (m, 1H), 1.54 (d, J¼7.2 Hz,
3H), 1.33e1.25 (m, 3H), 1.10e1.07 (m, 1H); 13C NMR (400 MHz,
NMR (400 MHz, CDCl3)
d ppm 175.09, 144.37, 141.97, 140.33,
135.51, 131.32, 129.32, 127.81, 127.41, 127.34, 127.34, 127.01, 125.94,
125.94, 124.71, 124.58, 122.35, 118.00, 107.54, 87.67, 84.26, 61.89,
51.86, 31.33, 26.15; ESI-HRMS: m/z calcd for C25H21NO2þHþ:
368.1645, found 368.1643.
CDCl3)
d ppm 174.89, 143.69, 142.30, 142.25, 133.57, 128.74, 127.79,
126.80, 125.61, 124.65, 124.20, 122.60, 107.58, 96.59, 86.65, 60.65,
51.49, 35.72, 33.25, 31.98, 26.28, 24.47, 22.64; ESI-HRMS: m/z calcd
for C23H23NO2þHþ: 346.1802, found 346.1799.
4.2.28. 100-Methyl-50-phenyl-4,5-dihydro-2H-dispiro [cyclopentane-
1,20-furan-30,300-indolin]-200-one (5a). Yellow grease; IR (KBr): 3045,
3031, 2972, 2886, 1710 (s), 1608 (s), 1476 (m), 1459 (m), 1375 (m),
4.2.33. 100-Methyl-50-phenyl-4,5-dihydro-2H-dispiro [cyclohexane-
1,20-furan-30,300-indolin]-200-one (5e). Yellow grease; IR (KBr): 3055,
3025, 2965, 2934, 1710 (s), 1611 (s), 1491 (m), 1469 (m), 1365 (m),
1347 (m) cmꢁ1; 1H NMR (400 MHz, CDCl3)
d
ppm 7.47 (d, J¼7.6 Hz,
2H), 7.38 (t, J¼7.6 Hz, 2H), 7.30e7.23 (m, 3H), 7.00 (t, J¼7.2 Hz, 1H),
6.82 (d, J¼7.6 Hz, 1H), 5.57 (t, J¼8.0 Hz, 1H), 3.23 (s, 3H), 2.90 (dd,
J¼12.8, 7.2 Hz,1H), 2.34 (dd, J¼12.8, 8.4 Hz,1H),1.99 (m,1H),1.80 (d,
J¼5.2 Hz, 4H),1.49 (d, J¼7.2 Hz, 2H),1.28 (s,1H); 13C NMR (400 MHz,
1342 (m) cmꢁ1; 1H NMR (400 MHz, CDCl3)
d
ppm 7.59 (d, J¼7.6 Hz,
2H), 7.42e7.32 (m, 3H), 7.28 (q, J¼6.8 Hz, 2H), 7.09 (t, J¼7.2 Hz, 1H),
6.85 (d, J¼8.0 Hz, 1H), 5.41 (t, J¼8.0 Hz, 1H), 3.20 (s, 3H), 2.70 (dd,
J¼12.8, 8.8 Hz, 1H), 2.58 (dd, J¼12.8, 7.2 Hz, 1H), 2.05 (d, J¼13.2 Hz,
1H), 1.86e1.42 (m, 6H), 1.36 (dt, J¼13.2, 4.0 Hz, 1H), 1.06e0.98 (m,
CDCl3)
d ppm 177.73, 143.44, 142.72, 131.36, 128.37, 128.37, 127.95,
127.13, 125.58, 125.58, 124.97, 122.21, 107.71, 95.38, 77.18, 59.04,
45.19, 36.59, 33.24, 26.25, 23.47, 23.31; ESI-HRMS: m/z calcd for
C22H23NO2þHþ: 334.1802, found 334.1800.
2H); 13C NMR (400 MHz, CDCl3)
d ppm 177.37,143.51,143.02,130.47,
128.30, 128.30, 128.02, 127.28, 126.21, 126.21, 125.20, 121.98, 107.89,
86.56, 78.20, 61.40, 44.36, 33.16, 32.89, 26.29, 25.33, 22.60, 22.55;
ESI-HRMS: m/z calcd for C23H25NO2þHþ: 348.1958, found 348.1955.
4.2.29. 100-Methyl-50-phenyl-4,5-dihydro-2H-dispiro [cyclopentane-
1,20-furan-30,300-indolin]-200-one (6a). Yellow grease; IR (KBr): 3048,
3032, 2975, 2891, 1710 (s), 1607 (s), 1474 (m), 1461 (m), 1374 (m),
4.2.34. 100-Methyl-50-phenyl-4,5-dihydro-2H-dispiro [cyclohexane-
1,20-furan-30,300-indolin]-200-one (6e). Yellow grease; IR (KBr): 3056,
3025, 2966, 2932, 1711 (s), 1610 (s), 1493 (m), 1465 (m), 1368 (m),
1348 (m) cmꢁ1; 1H NMR (400 MHz, CDCl3)
d
ppm 7.52 (d, J¼7.6 Hz,
2H), 7.46 (d, J¼7.6 Hz, 1H), 7.37 (t, J¼7.2 Hz, 2H), 7.29 (dd, J¼10.8,
7.6 Hz, 2H), 7.11 (t, J¼7.6 Hz, 1H), 6.87 (d, J¼7.6 Hz, 1H), 5.45 (t,
J¼8.4 Hz, 1H), 3.23 (s, 3H), 2.72 (dd, J¼12.4, 9.6 Hz, 1H), 2.57 (dd,
J¼12.4, 7.2 Hz, 1H), 1.97e1.82 (m, 3H), 1.72 (q, J¼9.2 Hz, 2H), 1.55
(dd, J¼8.0, 4.0 Hz, 1H), 1.44e1.18 (m, 2H); 13C NMR (400 MHz,
1342 (m) cmꢁ1; 1H NMR (400 MHz, CDCl3)
d
ppm 7.48 (d, J¼7.6 Hz,
2H), 7.37 (t, J¼7.6 Hz, 2H), 7.29e7.24 (m, 2H), 7.19 (d, J¼7.2 Hz, 1H),
6.99 (t, J¼7.2 Hz, 1H), 6.81 (d, J¼7.6 Hz, 1H), 5.72 (t, J¼7.6 Hz, 1H),
3.21 (s, 3H), 2.86 (dd, J¼12.8, 7.2 Hz, 1H), 2.40 (dd, J¼12.8, 9.2 Hz,
1H), 2.12 (d, J¼13.2 Hz, 1H), 1.85e1.01 (m, 9H); 13C NMR (400 MHz,
CDCl3)
d
ppm 176.55, 143.11, 142.99, 131.62, 128.35, 128.35, 128.04,
CDCl3) d ppm 178.11, 143.82, 143.58, 129.67, 128.33, 128.33, 128.07,
127.26, 125.85, 125.85, 124.73, 122.38, 107.88, 95.83, 78.33, 59.16,
45.31, 34.89, 34.79, 26.38, 23.68, 23.17; ESI-HRMS: m/z calcd for
C22H23NO2þHþ: 334.1802, found 334.1805.
127.00, 125.51, 125.51, 125.47, 121.88, 107.72, 85.83, 77.53, 61.63,
44.14, 35.37, 31.74, 26.13, 25.38, 22.67, 22.61; ESI-HRMS: m/z calcd
for C23H25NO2þHþ: 348.1958, found 348.1956.
4.2.30. 100,50-Dimethyl-50-phenyl-4,5-dihydro-2H-dispiro
[cyclo-
4.2.35. 100,50-Dimethyl-50-phenyl-4,5-dihydro-2H-dispiro [cyclohex-
ane-1,20-furan-30,300-indolin]-200-one (5f). Yellow grease; IR (KBr):
3049, 2974, 2935, 1709 (s), 1609 (m), 1498 (m), 1469 (m), 1371 (m),
pentane-1,20-furan-30,300-indolin]-200-one (5b). Yellow grease; IR
(KBr): 3052, 2965, 2938, 2928, 1712 (s), 1610 (m), 1492 (m), 1462
(m), 1369 (m), 1338 (m) cmꢁ1
;
1H NMR (400 MHz, CDCl3)
d
ppm
1337 (m); 1H NMR (400 MHz, CDCl3)
d
ppm 7.55 (dd, J¼7.2, 3.6 Hz,
7.71 (d, J¼7.6 Hz, 1H), 7.49 (d, J¼7.6 Hz, 2H), 7.36e7.29 (m, 3H), 7.23
(t, J¼7.2 Hz, 1H), 7.10 (t, J¼6.8 Hz, 1H), 6.86 (d, J¼7.2 Hz, 1H), 3.32 (d,
J¼13.2 Hz, 1H), 3.21 (s, 3H), 2.57 (d, J¼13.2 Hz, 1H), 1.74e1.53 (m,
3H), 7.36e7.20 (m, 4H), 7.08 (t, J¼7.6 Hz, 1H), 6.81 (d, J¼8.0 Hz, 1H),
3.28 (d, J¼13.2 Hz, 1H), 3.14 (s, 3H), 2.59 (d, J¼13.2 Hz, 1H),
1.76e1.62 (m, 7H), 1.46 (d, J¼13.2 Hz, 1H), 1.34e1.30 (m, 2H), 1.78
(dt, J¼13.2, 4.0 Hz, 1H), 1.03e0.94 (m, 2H); 13C NMR (400 MHz,
8H), 1.44e0.98 (m, 3H); 13C NMR (400 MHz, CDCl3)
d ppm 176.14,
151.34, 143.03, 133.22, 127.91, 127.91, 127.81, 126.27, 125.52, 124.64,
124.64, 122.17, 107.83, 96.90, 83.00, 60.11, 50.24, 35.69, 34.00, 33.28,
26.48, 23.76, 22.65; ESI-HRMS: m/z calcd for C23H25NO2þHþ:
348.1958, found 348.1961.
CDCl3) d ppm 177.09, 150.95, 143.58, 130.95, 127.91, 127.70, 127.70,
126.07, 125.99, 124.74, 124.74, 121.70, 107.81, 87.17, 83.07, 62.50,
48.91, 34.84, 34.79, 32.43, 26.31, 25.40, 23.02, 22.38; ESI-HRMS: m/z
calcd for C24H27NO2þHþ: 362.2115, found 362.2117.

L. Wang et al. / Tetrahedron 68 (2012) 1483e1491
1491
4.2.36. 100-Methyl-50,50-phenyl-4,5-dihydro-2H-dispiro [cyclohexane-
1,20-furan-30,300-indolin]-200-one (5g). Pale yellow solid; mp:
188e190 ꢃC; IR (KBr): 3057, 3024, 2930 (m), 2856, 1712 (s), 1609
2. (a) Claweon, P.; Lunn, P. M.; Whiting, D. A. J. Chem. Soc., Perkin Trans. 1 1990,
153e157; (b) Schaap, A. P.; Siddiqui, S.; Prasad, G.; Palomino, P.; Sandison, M.
Tetrahedron 1985, 41, 2229e2235; (c) Clawson, P.; Lunn, P. M.; Whiting, D. A. J.
Chem. Soc., Chem. Commun. 1984, 134e135; (d) Albini, A.; Arnold, D. R. Can. J.
Chem. 1978, 56, 2986e2990.
3. (a) Mueller, F.; Mattay, J. Angew. Chem., Int. Ed. Engl. 1992, 31, 206e221; (b)
Maer, F.; Karwe, A.; Mattav, J. J. Org. Chem. 1992, 57, 6080e6082; (c) Miiller, F.;
Mattay, J. Angew. Chem., Int. Ed. Engl. 1991, 30, 1336e1337.
4. (a) Cair, V.; Laurent, A.; Laurent, E.; Tardivel, R.; Cebulska, Z.; Bartnik, R. Nouv. J.
Chim. 1987, 11, 351e357; (b) Schaap, A. P.; Siddiqui, S.; Praead, G.; Rahman, A. F.
M.; Oliver, J. P. J. Am. Chem. Soc. 1984, 106, 6087e6088; (c) Schaap, A. P.; Prasad,
G.; Siddiqui, S. Tetrahedron Lett. 1984, 25, 3035e3038.
5. (a) Mizuno, K.; Sugita, H.; Hirai, T.; Maeda, H.; Otsuji, Y.; Yasuda, M.; Ha-
shiguchi, M.; Shima, K. Tetrahedron Lett. 2001, 42, 3363e3366; (b) Dinnocenzo,
J. P.; Todd, M. P.; Simpson, T. R.; Gould, I. R. J. Am. Chem. Soc. 1990, 112,
2462e2464.
6. Pan, J.; Zhang, W.; Zhang, J.; Lu, S. Tetrahedron Lett. 2007, 48, 2781e2785.
7. (a) Galliford, C. V.; Scheidt, K. A. Angew. Chem., Int. Ed. 2007, 46, 8748e8758; (b)
Alluri, S.; Feng, H.; Livings, M.; Samp, L.; Biswas, D.; Lam, T. W.; Lobkovsky, E.;
Ganguly, A. K. Tetrahedron Lett. 2011, 52, 3945e3948; (c) Pedras, M.; Soledade,
C.; Hossain, M. Org. Biomol. Chem. 2006, 4, 2581e2590; (d) Bignan, G. C.; Bat-
tista, K.; Connolly, P. J.; Orsini, M. J.; Liu, J.; Middleton, S. A.; Reitz, A. B. Bioorg.
Med. Chem. Lett. 2005, 15, 5022e5026; (e) Kyei, A. S.; Tchabanenko, K.; Baldwin,
J. E.; Adlington, R. M. Tetrahedron Lett. 2004, 45, 8931e8934; (f) Efange, S. M. N.;
Kamath, A. P.; Khare, A. B.; Kung, M.-P.; Mach, R. H.; Parsons, S. M. J. Med. Chem.
1997, 40, 3905e3914; (g) Cui, C.-B.; Kakeya, H.; Okada, G.; Onose, R.; Osada, H. J.
Antibiot. 1996, 49, 527e533; (h) Smallheer, J. M.; Otto, M. J.; Amaral-Ly, C. A.;
Earl, R. A.; Myers, M. J.; Pennev, P.; Montefiori, D. C.; Wuonola, M. A. Antiviral
Chem. Chemother. 1993, 4, 27e39.
8. (a) Marti, C.; Carreira, E. M. Eur. J. Org. Chem. 2003, 12, 2209e2219; (b) White, J.
D.; Li, Y.; Ihle, D. C. J. Org. Chem. 2010, 75, 3569e3577; (c) Thomson, J. E.; Kyle,
A. F.; Ling, K. B.; Smith, S. R.; Slawin, A. M. Z.; Smith, A. D. Tetrahedron 2010, 66,
3801e3813; (d) Allous, I.; Comesse, S.; Berkes, D.; Alkyat, A.; Daich, A. Tetra-
hedron Lett. 2009, 50, 4411e4415; (e) Iwasaki, H.; Eguchi, T.; Tsutsui, N.; Ohno,
H.; Tanaka, T. J. Org. Chem. 2008, 73, 7145e7152.
(m), 1490 (m), 1448 (m), 1371 (m), 1350 (m) cmꢁ1 1H NMR
;
(400 MHz, CDCl3)
d
ppm 7.63 (d, J¼8.4 Hz, 4H), 7.26 (q, J¼8.0 Hz,
4H), 7.16e7.09 (m, 3H), 6.73 (t, J¼8.4 Hz, 2H), 6.65 (d, J¼7.2 Hz, 1H),
3.70 (d, J¼13.2 Hz, 1H), 3.21 (d, J¼13.2 Hz, 1H), 3.15 (s, 3H), 1.92 (dd,
J¼13.6, 2.0 Hz, 1H), 1.85e1.69 (m, 2H), 1.61 (d, J¼0.4 Hz, 1H), 1.54
(dd, J¼13.2, 2.4 Hz, 1H), 1.44e1.38 (m, 2H), 1.32e1.25 (m, 2H), 1.05
(td, J¼12.8, 3.6 Hz, 1H); 13C NMR (400 MHz, CDCl3)
d ppm 176.85,
150.17, 149.33, 143.10, 130.87, 128.08, 128.08, 127.85, 127.85, 127.59,
126.22, 126.13, 126.09, 125.10, 125.10, 125.00, 125.00, 121.72, 107.50,
87.34, 86.15, 62.33, 48.64, 34.02, 33.02, 26.41, 25.35, 23.22, 22.38;
ESI-HRMS: m/z calcd for C29H29NO2þHþ: 424.2271, found 424.2274.
4.2.37. 100-Methyl-4,5-dihydro-2H-dispiro[cyclohexane-1,20-indeno
[1,2-b]furan-30,300-indolin]-200-one (5h). Pale yellow solid; mp:
152e154 ꢃC; IR (KBr): 3052, 3027, 2931 (m), 2901,1708 (s),1610 (m),
1465 (m),1367 (m),1342 (m) cmꢁ1; 1H NMR (400 MHz, CDCl3)
d ppm
7.58 (d, J¼8.4 Hz,1H), 7.38 (d, J¼7.2 Hz,1H), 7.32e7.26 (m, 3H), 7.17 (t,
J¼4.0 Hz, 1H), 7.09 (t, J¼7.6 Hz, 1H), 6.82 (d, J¼7.6 Hz, 1H), 5.81 (d,
J¼8.0 Hz,1H), 3.57e3.51 (m,1H), 3.45 (dd, J¼17.6, 3.6 Hz,1H), 3.17 (s,
3H), 2.94 (dd, J¼17.6, 10.4 Hz, 1H), 1.84 (dd, J¼13.2, 2.4 Hz, 1H),
1.72e1.44 (m, 6H), 1.28 (dd, J¼16.0 Hz, 1H), 1.15e1.07 (m, 1H); 13C
NMR (400 MHz, CDCl3) d ppm 175.40, 143.52, 143.43, 142.31, 131.00,
128.58, 127.94, 126.80, 125.49, 124.79, 124.49, 122.04, 107.62, 88.21,
85.80, 64.48, 50.67, 33.15, 32.42, 32.03, 26.07, 25.48, 22.47, 22.14;
ESI-HRMS: m/z calcd for C24H25NO2þHþ: 360.1958, found 360.1961.
9. (a) Grubb, G. S.; Zhi, L.; Jones, T. K.; Tegley, C. M.; Fensome, A.; Miller, L. L.;
Ullrich, J. W.; Bender, R. H. W.; Zhang, P.; Wrobel, J. E.; Edwards, J. P. PCT Int.
Appl. Patent 2,000,066,167, 2000. (b) Demerson, C. A.; Humber, L. G. U.S. Patent
4,226,860 A, 1980. (c) Chafeev, M.; Chowdhury, S.; Fraser, R.; Fu, J.; Kamboj, R.;
Hou, D.; Liu, S.; Bagherzadeh, M. S.; Sviridov, S.; Sun, S. i; Sun, J. u; Chakka, N.;
Hsieh, T.; Raina, V. PCT Int. Appl. Patent 2,006,110,917, 2006.
Acknowledgements
We are grateful to the National Nature Science Foundation of
China (Grant No. 20872056) for financial support.
10. (a) Alcaide, B.; Almendros, P.; Rodríguez-Acebes, R. J. Org. Chem. 2006, 71,
2346e2351; (b) Alcaide, B.; Almendros, P.; Rodriguez-Acebes, R. Chem.dEur. J.
2005, 11, 5708e5712; (c) Ganguly, A. K.; Wang, C. H.; Chan, T. M.; Ing, Y. H.;
ꢀ
Buevich, A. V. Tetrahedron Lett. 2004, 45, 883e886; (d) Lopez-Alvarado, P.;
Supplementary data
~
ꢀ
Steinhoff, J.; Miranda, S.; Avendano, C.; Menendez, J. C. Tetrahedron 2009, 65,
1660e1672; (e) Tratrat, C.; Giorgi-Renault, S.; Husson, H.-P. J. Org. Chem. 2000,
65, 6773e6776.
Supplementary data associated with this article can be found, in
the online version, at doi:10.1016/j.tet.2011.12.018. These data in-
clude MOL files and InChIKeys of the most important compounds
described in this article.
11. X-ray data for compound 3q: C21H20BrNO2, Mr¼398.29, monoclinic, space
ꢁ
ꢁ
ꢁ
b
group P2(1)/c, a¼10.532(3) A, b¼8.343(3) A, c¼20.446(6) A,
¼100.037(3)ꢃ,
V¼1769.0(9) A . Colorless block, Dc¼1.495 g cmꢁ3, T¼296(2) K, Z¼4,
m
(Mo K
a
)¼
3
ꢁ
0.71073 mmꢁ1, 2qmax¼51.0ꢃ, 3271 reflections measured, 2213 unique, (Rint¼0.
0657), which were used in all calculations. The final wR(F2) was 0.0788 (for all
data), R1¼0.0905. CCDC 842521.
References and notes
12. (a) Rehm, D.; Weller, A. Isr. J. Chem. 1970, 8, 259e271; (b) Weller, A. Z. Phys.
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13. (a) Martiny, M.; Steckhan, E.; Esch, T. Chem. Ber. 1993, 126, 1671e1682; (b)
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S.; Shealer, S. E. J. Chem. Soc., Chem. Commun. 1973, 677e678.
14. (a) Anthony, W. C. J. Org. Chem. 1966, 31, 77e81; (b) Baiocchi, L.; Giannangeli, M.
J. Heterocycl. Chem. 1988, 25, 1905e1909.
1. (a) Griesbeck, A. G.; Hoffmann, N.; Warzecha, K.-D. Acc. Chem. Res. 2007, 40,
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