Regioselective synthesis of spiro naphthofuranone-pyrazoline via a [3+2] cycloaddition of benzoaurones with nitrile imines

Full text of DOI:10.1016/j.tet.2020.131355

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Regioselective synthesis of spiro naphthofuranone-pyrazoline via a [3+2]
cycloaddition of benzoaurones with nitrile imines
Yingpeng Su, Chenglong Ma, Yanan Zhao, Caixia Yang, Yawei Feng, Ke-Hu Wang,
Danfeng Huang, Congde Huo, Yulai Hu
PII:
S0040-4020(20)30510-X
https://doi.org/10.1016/j.tet.2020.131355
TET 131355
DOI:
Reference:
To appear in: Tetrahedron
Received Date: 23 March 2020
Revised Date: 31 May 2020
Accepted Date: 22 June 2020
Please cite this article as: Su Y, Ma C, Zhao Y, Yang C, Feng Y, Wang K-H, Huang D, Huo C, Hu Y,
Regioselective synthesis of spiro naphthofuranone-pyrazoline via a [3+2] cycloaddition of benzoaurones
with nitrile imines, Tetrahedron (2020), doi: https://doi.org/10.1016/j.tet.2020.131355.
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Regioselective synthesis of spiro
naphthofuranone-pyrazoline via a [3+2]
cycloaddition of benzoaurones with nitrile
imines
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Yingpeng Su*, Chenglong Ma, Yanan Zhao, Caixia Yang**, Yawei Feng, Haiyang He, Ke-Hu Wang, Danfeng
Huang, Congde Huo, Yulai Hu
College of Chemistry and Chemical Engineering, Northwest Normal University, 967 Anning East Road,
Lanzhou 730070, P. R. China.

1
Tetrahedron
journal homepage: www.elsevier.com
Regioselective synthesis of spiro naphthofuranone-pyrazoline via a [3+2]
cycloaddition of benzoaurones with nitrile imines
Yingpeng Su∗ , Chenglong Ma, Yanan Zhao, Caixia Yang∗ ∗ , Yawei Feng, Ke-Hu Wang, Danfeng Huang,
Congde Huo, and Yulai Hu
a
College of Chemistry and Chemical Engineering, Northwest Normal University, 967 Anning East Road, Lanzhou 730070, P. R. China
ARTICLE INFO
ABSTRACT
Article history:
Received
Received in revised form
Accepted
A regioselective [3+2] cycloaddition reaction of benzoaurones with nitrile imines was
developed. Resorting to this efficient strategy, a series of compelling spiro [naphthofuran-2,3'-
pyrazoline]-3-ones were efficiently obtained in good to excellent yields (65% to 94% yield) with
high regioselectivity. Furthermore, the reported method featuresd several advantages including
simple operation, mild reaction condition, catalyst free, good functional group tolerance and
facile gram scale-up.
Available online
Keywords:
Spirocyclic compound
2
009 Elsevier Ltd. All rights reserved.
[
3+2] cycloaddition
benzoaurone
nitrile imine
pyrazoline
1
. Introduction
OH
OH
OH
OH
Spiro-pyrazolines[1] represent prominent subclass of highly
valuable structural motifs in the synthetic bioactive
compounds[2] and organic building blocks[3]. For instance,
compound I showed good cytotoxicity against MCF–7 cellular
activity[2a]; Compound II revealed promising hypnotic
potentiating effects[2b]. (Figure 1) Due to the synthetic and
biological relevance of these spiro-pyrazolines, considerable
attentions have also been contributed to construct those motifs
and investigate the potential biological activities[2-4]. In spite of
above impressive advances, it is still highly desirable to explore
other type of spiro-pyrazolins motifs.
Ph
O
N
O
Me
N
HO
Me
O
O
N
N
O
Ph
Me
Ph
O
O
Br
O
O
HO
N
N
N
Ph
Me
H
Ph
I
II
Abiesinol A
HO
Me
OMe
OH
CHO
O
Me
H
Me
OH
Me
O
On the other hand, aurones are an important category of
unique natural and synthetic products, which exhibited excellent
biological activity[5]. Meanwhile, as versatile synthetic building
blocks, aurones and its derivatives [6, 7] have also received
comprehensive attentions [6a, 8]. Especially, they were employed
to construct the spiro benzofuranone-carbocyclic or -heterocyclic
compounds via various cycloadditions.[7b-n] Given the above
facts and interesting conformational features of spirocyclic
compounds, connecting the benzofuranone skeleton to the
pyrazoline unit assembling the novel spiro-benzofuranone-
pyrozoline motif would be a very appealing strategy for the
discovery of the potential biological products. Hence, as part of
O
H
HO
HO
O
Me
O
Me
O
Me
HO
O
OH
OH
Applanatumin A
Involucratustones B
Figure 1. Selected compounds with spiropyrazoline and
spirobenzofuranone skeletons
our continuous efforts in the construction of spirocyclic
compounds[9] with nitrilimines via the [3+2] cycloadditoin
Scheme 1, eqn (a))[9a], herein we reported an efficient synthesis
(
of the spiro-benzoaurone-pyrazoline compounds via
a
—
——
∗
∗
Corresponding author. e-mail: suyp51@nwnu.edu.cn
∗ Corresponding author. e-mail: yangcx @nwnu.edu.cn

2
Tetrahedron
regioselectivity [3+2] cycloaddition of benzoaurones with
Table 1
a
Survey of Reaction Conditions
nitrile imines (Scheme 1, eqn (b)).
Yield of
3
Entry
Base
Solvent
Time/(h)
b
a/(%)
30
84
80
70
30
19
83
85
68
80
74
74
70
91
89
82
87
86
88
87
1
2
3
4
5
6
KOH
THF
THF
THF
THF
THF
THF
THF
THF
THF
DCM
24
24
24
10
24
24
24
24
24
24
24
24
3
Scheme 1 Synthesis of the spiro-pyrazolines with nitrile imines via [3+2]
cycloaddition
K CO
2 3
Na CO3
2
. Results and discussion
2
Cs CO3
2
In our initial investigation, readily available benzoaurone 1a
and hydrazonoyl chloride 2a were employed as the model
substrate for screening the optimal cycloaddition conditions. As
shown in table 1, screening of bases was carried out in THF at
room temperature, both the inorganic or the organic bases were
able to promote this cycloaddition and give the desired product
Et N
3
DBU
c
7
K CO3
2
d
8
K CO3
3
a
with high regioselectivity, which was confirmed
unambiguously by single crystal X-ray analysis (Table 1, entries
–6). Based on these results, K CO was chosen as the optimal
2
e
9
K CO3
2
1
2
3
base(Table 1, entry 2). Increasing the amounts of K CO or
10
K CO
2 3
2
3
hydrazonoyl 2a had no obviously improvements on the reaction
rate and yield (Table 1, entries 7 and 8). However, decreasing the
amount of hydrazonoyl chloride 2a to 1.0 equivalent led to a
significant erosion in the yield (Table 1, entry 9). With respect to
1
1
K CO3
2
CH CN
3
12
K CO3
2
Toluene
EtOH
1
3
K CO3
2
solvents, DCM, CH CN, toluene, and EtOH were all found to be
3
inferior to THF in this reaction (Table 1, entries 10–13).
Interestingly, we observed that the use of a polar protic solvent
such as EtOH accelerated the reaction although the yield of 3a
decreased slightly(Table 1, entry 13). This result might induce by
the solubility of K CO . Consequently, the cosolvent THF/H O
14
K CO3
2
THF/H O (200/1)
4
2
f
1
1
1
1
1
2
5
6
7
8
9
0
K CO3
2
THF
24
4
K CO3
2
THF/H O (10/1)
2
2
3
2
K CO3
THF/H O (100/1)
2
4
(
V/V = 200/1) and phase transfer catalyst (Bu NBr) were
2
4
investigated respectively (Table 1, entries 14 and 15). To our
delight, the reaction proceeded efficiently in the cosolvent to
afford the spirocyclic compound 3a in 91% yield for 4 h (Table
K CO3
2
THF/H O (500/1)
7
2
g
h
K CO3
THF/H O (200/1)
2
5
2
1
, entry 14). Meanwhile, Bu NBr also slightly improved the
4
K CO3
2
THF/H O (200/1)
3
2
yield, but did not affect the reaction efficiency (Table 1, entry
a.
1
1
5). Then ratio of THF/H O was investigated (Table 1, entries
Reaction condtions: 1a (0.12 mmol), 2a (0.18 mmol, 1.5 equiv.)
and base (0.18 mmol, 1.5 equiv.) in dry solvent (2 mL) at room
2
6-18), the results indicated that THF/H O (V/V = 200/1) gave
2
the best yield. Finally, the effect of reaction temperature was
examined. The results showed that neither decreasing nor
increasing reaction temperature had positive effect on yielding
the product 3a (Table 1, entries 19 and 20).
temperature for the indicated time;
b
.
Isolated yields;
c
d
e
f
0.24 mmol (2.0 equiv.) of K CO was used;
2
3
With the optimized conditions in hand, we next investigated
0.24 mmol (2.0 equiv.) of 2a was used;
2
the scope of the reaction with different aryl (R groups)
0
0
.12 mmol (1.0 equiv.) of 2a was used;
substituted benzoaurones 1. As shown in Table 2, the
benzoaurone derivatives 1 bearing various aryl groups with
diverse steric and electronic properties (1b–1k), were well
tolerated in this process and provided the corresponding products
.012 mmol (0.1 equiv.) of Bu NBr was added;
4
g
h
o
The reaction was performed at 0 C;
3
b–3k in good to excellent yields (Table 2, entries 2–12). In
The reaction was performed under the refluxing condition.
comparison, the electron-rich substrates (1a, 1i–1k) were
amenable to this protocol and gave the spirocyclic compounds in
excellent yields (Table 2, entries 1 and 9–11, 90%–94%), albeit
the electron-poor substrates (1c–1g) also afforded the desired
product in good yields (Table 2, entries 3–7, 77%–86%).
Notably, ortho-Cl- and ortho-Me-benzoaurones 1b and 1h gave
relatively lower yields in this transformation (Table 2, entries 2
and 8). These results indicated that the steric hindrance
influenced the formation of these spiro compounds. β-Naphthyl,
2
-thienyl, the typical polycyclic and hetrocyclic aromatic
substituents, were also compatible with the cycloaddition. The
corresponding substrates afforded desired products 3l–3n in good
yields (Table 2, entries 12-14). Furthermore, challenging the
bulky tert-Bu substituted benzoaurone 1o also gave the
spirocyclic product 3o in 69% yield. Then, the electronic
1
properties of naphthyl ring segment was tested (R groups).
Benzoaurones 1p and 1q derived from 6-Br- and 7-OMe-2-
naphthol were also well tolerated, giving spiro compounds 3p
and 3q in the excellent yields (Table 2, entries 16 and 17).
2
-
f
u
r
y
l
a
n
d

3
Table 2
Scope of Benzoaurones
Table 3
a
Scope of Hydrazonoyl Chlorides
1
2
Time
Yield
(%)
Entry
1
1
R
R
3
b
(h)
4
5
Time
(
Yield
b
Entry
2
R
R
3
h)
7
5
7
5
5
5
5
5
5
5
7
4
4
6
5
6
5
(%)
73
77
83
84
86
83
72
82
89
88
73
77
81
65
71
83
83
9
1
c
1a
H
Ph
3a
4
(
87)
72
7
1
2
3
4
5
6
7
8
9
2b
2c
2d
2e
2f
2-Cl-Ph
3-Cl-Ph
4-Cl-Ph
4-Br-Ph
4-F-Ph
Ph
Ph
3r
3s
2
3
4
5
6
7
8
9
1b
1c
1d
1e
1f
H
H
H
H
H
H
H
H
H
H
2’-Cl-Ph
3’-Cl-Ph
4’-Cl-Ph
4’-Br-Ph
4’-F-Ph
3b
3c
3d
3e
3f
6
5
5
5
5
3
4
5
5
5
Ph
3t
85
86
83
78
78
90
92
94
Ph
3u
Ph
3v
2g
2h
2i
4-CF -Ph
Ph
3w
3x
3
1g
1h
1i
4’-CF -Ph
3g
3h
3i
3
2-MeO-Ph
3-MeO-Ph
4-MeO-Ph
4-Me-Ph
2-Py
Ph
2’-Me-Ph
3’-Me-Ph
4’-Me-Ph
4’-MeO-Ph
Ph
3y
2j
Ph
3z
1
1
0
1
1j
3j
1
1
1
1
1
1
1
1
0
1
2
3
4
5
6
7
2k
2l
Ph
3aa
3ab
3ac
3ad
3ae
3af
3ag
1k
3k
Ph
2
’-
2m
2n
2o
2p
2q
2r
2-Furyl
2-Thienyl
Chx
Ph
1
2
1l
H
3l
6
90
Naphthyl
Ph
1
1
1
1
1
3
4
5
6
7
1m
1n
1o
1p
1q
H
H
2’-Furyl
3m
3n
3o
3p
3q
5
6
5
5
5
73
72
69
88
90
Ph
2’-Thienyl
Styryl
Ph
t
H
Bu
Ph
4-F-Ph
6-Br
7-MeO
Ph
Ph
Ph
4-Br-Ph 3ah
4
-Me-
Ph
a
18
2s
Ph
3ai
5
87
Reaction conditons: 1 (0.12 mmol), 2a (0.18 mmol, 1.5 equiv.)
and K CO (0.18 mmol, 1.5 equiv.) in 2 mL of THF with 10 uL
of H O at room temperature for the indicated time;
2
3
a
Reaction conditons: 1a (0.12 mmol), 2 (0.18 mmol, 1.5 equiv.)
and K CO (0.18 mmol, 1.5 equiv.) in 2 mL of THF with 10 uL
2
2
3
b
Isolated yields;
of H O at room temperature for the indicated time;
2
c
b
isolated yield obtained in the gram-scale reaction.
Isolated yields.
Finally, to show the synthetic potential of this [3+2]
cycloaddition reaction, a gram-scale reaction of 1a (1.0 g, 3.7
mmol) with hydrozonoyl chloride 2a was conducted under the
optimized reaction conditions. As expected, the product 3a was
obtained in 87% yield (1.5 g) in this gram-scale reaction (Table
in the lower yields of spirocyclic compounds (3r in 73% yield;
3x in 72% yield). These results indicated that the steric hindrance
dramatically affected the reaction yields. Furthermore, 2-pyridyl,
2-furanyl, and 2-thienyl nitrilimine (2l−2n) were also tolerated
and yielded products in good yields (Table 3, 3ab–3ad, 73–
84%). Notably, the labile hydrazonoyl chlorides 2o and 2p
derived from cyclohexanaldehyde and cinnamaldehyde were also
applicable to this annulation and furnished the target products in
the yields of 65% and 71%, respectively (Table 3, 3ae and 3af).
Finally, hydrazonoyl chlorides with different electronic
2
, entry 1).
To further demonstrate the practical utility of present
approach for constructing spirocyclic compounds, we
4
investigated the substrate scope of hydrazonoyl chlorides (R and
5
R groups). As shown in table 3, hydrazonoyl chlorides bearing
5
properties aryl groups (R group) at 1-N-positon were extended.
either electron-donating or electron-withdrawing aryl groups at
4
The substrates 2q–2s possessing 4-F-, 4-Br- and 4-Me-phenyl
groups successfully took part in the [3 + 2] cycloaddition and
afforded desired products in good yields without influence from
electronic properties (Table 3, 3ag–3ai, 83%-86% yield).
the 3-position (R groups) reacted smoothly under the optimized
conditions and provided the desired spirocyclic compounds in
good to high yields (Table 3, entries 1–10). According to the4
obtained results, we observed that the electronic properties of R
substituents on the hydrazonoyl chlorides did not influence the
reaction (Table 3, 3s–3w and 3y–3aa). However, ortho-Cl- and
ortho-OMe-substituted hydrazonoyl chlorides 2b and 2h resulted

4
Tetrahedron
Table 4
Scope of Benzofuranones
allenic C [10b, 10c] took part in this [3+2] cycloaddition via
asynchronous transition state (TS) through two-center
a
interaction between carbenoid carbon of C and electrophilic
center of benzoaurone 1a. Consequently, the spiro
naphthofuranone-pyrazoline compound 3a formed with a high
regioselectivity.
Ph
Ph
O
Ph
O
R1
R1
N
2
a
N
O
K CO
2
3
O Ph
4
or
6
3. Conclusions
THF/H O (200/1), rt
2
or
In summary, we have reported an efficient and regioselective
3+2] dipolar cycloaddition reaction of benzoaurone with in situ
O
O
[
O
O
R3
generated nitrile imine. This protocol provides a facile access to
various interesting spiro naphthofuranone-pyrazoline compounds
in good to excellent yields. Moreover, the reaction is proved to
be efficient on large scale. The further investigations on 1,3-
dipolar cycloaddition reaction to construct compelling spirocyclic
compounds are underway in our group.
Ph
N
R3
N
Ph
5
7
4
. Experimental section
4
.1. General remarks
a
Reaction conditons: aurones 4 or 5 (0.12 mmol), 2a (0.18 mmol,
All solvents were treated according to standard procedures.
1
.5 equiv.) and K CO (0.18 mmol, 1.5 equiv.) in 2 mL of THF
Reagents were obtained from commercial suppliers and used
without further purification unless otherwise noted. Silica gel
column chromatography was carried out using 250–400 mesh
silica gel., Silica gel 60 F254 were used for thin layer
chromatography (TLC). The progress of the reactions was
monitored by TLC. TLC plates were analyzed by exposure to
ultraviolet (UV) light. NMR experiments were carried out in
2
3
with 10 uL of H O at room temperature for the indicated time;
2
b
Isolated yields.
1
13
deuterated chloroform (CDCl3). H and C NMR spectra were
recorded using Varian Mercury 400 plus (400 MHz) or Agilent
DD2 600 (600 MHz) spectrometer. Chemical shifts are reported
1
as δ values relative to internal TMS (δ = 0.00 ppm for H NMR)
1
13
and chloroform (δ = 7.26 ppm for H NMR, 77.0 ppm for
C
NMR) in parts per million (ppm). The following abbreviations
are used for the multiplicities: s: singlet, d: doublet, dd: doublet
of doublet, t: triplet, q: quartet, m: multiplet. Coupling constants
(J) are reported in hertz (Hz). Melting points were uncorrected.
High resolution mass spectra (HRMS) were recorded on a Micro
TOF-QII/Q-Exactive spectrometer. Details for the preparation of
benzoaurones 1 were described in Supplementary Material. All
materials 2 were prepared according to literatures[6b, 11].
4
.2. General procedure for the synthesis of the spiro products via
[
3+2] cycloadditon
To the mixture of naphthoaurone 1a (0.12 mmol), hydrazonyl
chlorides (0.18 mmol, 1.5 equiv) in THF (2 mL) and H O (10
2
ꢀ
L) were added K CO3 (0.18 mmol, 1.5 equiv) at room
2
temperature. The reaction was stirred at this temperature and
monitored by TLC. After 1 was consumed, the reaction mixture
was concentrated under vacuum and the residue was purified by
silica gel column chromatography (petroleum ether/ethyl acetate
Scheme 2 Proposed mechanism for the [3+2] cycloaddition
To further demonstrate the generality of this synthetic method,
other aurones derivered from benzofuran-3-one (coumaran-3-
one) 4 and benzofuran-2-one (coumaran-2-one) 5 with nitrile
imine 2a were surveyed under the optimum conditions (Table 4).
To our delight, all of these aurones reacted smoothly, and
provided the corresponding products in good to excellent yields.
Comparison with the benzofuran-2-one, benzofuran-3-one gave
much better results in the yields (6a and 6b vs 7a and 7b), which
may be due to steric effects.
2
0:1–10:1) to afford the spiro product 3.
4.2.1. 2',4',5'-triphenyl-2',4'-dihydro-3H-
spiro[naphtho[2,3-b] furan-2,3'-pyrazol] -3-one (3a)
o
1
Yellow solid; 51 mg, 91% yield; mp 168–170 C; H NMR
(
400 MHz, CDCl ) δ 8.82 (d, J = 8.4 Hz, 1H), 7.90 (d, J = 8.8
3
Based on our experimental results and previous literature
reports[6d, 6e, 9-10], a proposed mechanism for the [3+2]
cycloaddition of benzoaurones with nitrile imines was proposed
Hz, 1H), 7.77 (d, J = 8.0 Hz, 1H), 7.74–7.70 (m, 1H), 7.57–7.55
m, 2H), 7.52–7.48 (m, 1H), 7.27–7.30 (m, 3H), 7.15–7.14 (m,
(
4
1
1
1
H), 7.09–7.04 (m, 5H), 6.92–6.87 (m, 1H), 6.68 (d, J = 8.8 Hz,
(
Scheme 2). First, hydrazonoyl chloride 2a reacted with K CO
13
2
3
H), 5.26 (s, 1H). C NMR (100 MHz, CDCl ) δ 196.9, 172.0,
3
to generate nitrile imines with different resonance structures Aꢀ
D. Then in situ generated nitrile imine reacted with benzoaurone
a. In this produce, the much reasonable nitrile imine resonance
49.7, 141.8, 141.4, 131.0, 131.0, 130.2, 130.2, 129.1, 129.1,
28.9, 128.7, 128.6, 128.3, 128.1, 128.0, 127.8, 127.1, 125.7,
1

5
1
23.3, 122.2, 116.0, 113.1, 103.2, 64.0; HRMS(ESI) calcd. for
(m, 3H), 7.30–7.27 (m, 3H), 7.15–7.14 (m, 4H), 7.04–7.02 (m,
2H), 6.92–6.90 (m, 1H), 6.77 (t, J = 8.4 Hz, 2H), 6.72 (d, J = 9.0
+
C H N O [M + H] 467.17540; found: 467.17594.
32
23
2
2
13
Hz, 1H), 5.26 (s, 1H). C NMR (150 MHz, CDCl ) δ 196.7,
71.9, 162.3 (d, J = 246.0 Hz), 149.4, 141.7, 141.6, 131.9, 130.8,
30.3, 129.2, 129.1, 129.0, 128.7, 128.5, 128.4, 127.1, 126.9 (d, J
3.0 Hz), 125.8, 123.3, 122.3, 116.1, 115.2 (d, J = 22.5 Hz),
13.1, 113.1, 103.1, 63.2; HRMS(ESI) calcd. for C H FN O
2
3
4
.2.2. 4'-(2-chlorophenyl)-2',5'-diphenyl-2',4'-
1
1
=
dihydro-3H-spiro[naphtho[2,3-b]furan-2,3'-
pyrazol] -3-one (3b)
o
1
Yellow solid; 43 mg, 72% yield; mp 200–201 C; H NMR
1
3
2
22
2
(600 MHz,CDCl ) δ 8.82 (d, J = 8.4 Hz, 1H), 7.94 (d, J = 9.0 Hz,
+
3
[
M + H] 485.16598; found: 485.16590.
1
H), 7.79 (d, J = 8.4 Hz, 1H), 7.72 (t, J = 7.2 Hz, 1H), 7.53–7.50
(
m, 3H), 7.28–7.26 (m, 3H), 7.19–7.18 (m, 1H), 7.15–7.13 (m,
4.2.7. 2',5'-diphenyl-4'-(4-(trifluoromethyl)phenyl)-
2',4'-dihydro-3H-spiro[naphtho[2,3-b]furan-2,3'-
pyrazol] -3-one (3g)
4
1
1
1
1
H), 7.10–7.06 (m, 3H), 6.92–6.89 (m, 1H), 6.70 (d, J = 9.0 Hz,
13
H), 5.90 (s, 1H). C NMR (150 MHz, CDCl ) δ 196.3, 171.2,
3
o
1
49.2, 141.7, 141.2, 134.4, 133.4, 130.7, 130.3, 129.6, 129.3,
29.3, 129.1, 129.0, 129.0, 128.8, 128.6, 128.4, 127.0, 126.4,
25.8, 123.5, 122.1, 115.9, 113.5, 112.9, 1+ 02.4, 59.6;
Yellow solid; 50 mg, 78% yield; mp 173–175 C; H NMR
(600 MHz, CDCl ) δ 8.82 (d, J = 8.4 Hz, 1H), 7.94 (d, J = 9.0
3
Hz, 1H), 7.80 (d, J = 8.4 Hz, 1H), 7.74 (t, J = 7.8 Hz, 1H), 7.54–
7.42 (m, 3H), 7.35 (d, J = 7.8 Hz, 2H), 7.31–7.27 (m, 3H), 7.19
(d, J = 7.8 Hz, 2H), 7.16–7.15 (m, 4H), 6.93–6.91 (m, 1H), 6.68
HRMS(ESI) calcd. for C H ClN O [M + H] 501.13643;
found: 501.13641.
32
22
2
2
13
(
d, J = 8.4 Hz, 1H), 5.33 (s, 1H). C NMR (150 MHz, CDCl ) δ
3
4
.2.3. 4'-(3-chlorophenyl)-2',5'-diphenyl-2',4'-
1
1
1
1
96.4, 171.8, 148.8, 141.8, 141.5, 135.3, 130.6, 130.5, 130.4,
30.2 (q, J = 33 Hz), 129.3, 129.2, 129.2, 128.8, 128.5, 128.5,
27.0, 125.9, 125.0 (q, J = 4.5 Hz), 123.8 (q, J = 271.5 Hz),
dihydro-3H-spiro[naphtho[2,3-b]furan-2,3'-
pyrazol] -3-one (3c)
o
1
Yellow solid; 46 mg, 77% yield; mp 179–181 C; H NMR
23.3, 122.5, 116.3, 113.0, 112.9, 103.0, 63.3; HRMS(ESI)
(600 MHz, CDCl ) δ 8.80 (d, J = 7.8 Hz, 1H), 7.93 (d, J = 9.0
+
3
calcd. for C H F N O [M + H] 535.16279; found: 535.16273.
33
22
3
2
2
Hz, 1H), 7.77 (d, J = 8.4 Hz, 1H), 7.71 (t, J = 7.8 Hz, 1H), 7.54–
7
7
6
.52 (m, 2H), 7.50 (t, J = 8.4 Hz, 1H), 7.28–7.24 (m, 3H), 7.15–
.08 (m, 6H), 6.99 (t, J = 7.2 Hz, 1H), 6.94–6.93 (m, 1H), 6.91–
.88 (m, 1H), 6.73 (d, J = 9.0 Hz, 1H), 5.21 (s, 1H). C NMR
4.2.8. 2',5'-diphenyl-4'-(o-tolyl)-2',4'-dihydro-3H-
spiro[naphtho[2,3-b] furan-2,3'-pyrazol] -3-one (3h)
13
o
1
Yellow solid; 45 mg, 78% yield; mp 209–211 C; H NMR
(
150 MHz, CDCl ) δ 196.6, 172.1, 150.3, 141.6, 141.4, 136.3,
(400 MHz, CDCl ) δ 8.81 (d, J = 8.4 Hz, 1H), 7.89 (d, J = 8.8
3
3
1
1
1
35.3, 130.8, 130.3, 130.2, 129.2, 129.1, 128.7, 128.6, 128.6,
28.4, 128.1, 128.1, 126.7, 125.7, 123.3, 122.4, 119.4, 116.2,
13.2, 113.1, 103.1, 63.5; HRMS(ESI) calcd. for C H ClN O
Hz, 1H), 7.76 (d, J = 8.0 Hz, 1H), 7.74–7.70 (m, 1H), 7.56–7.54
(m, 2H), 7.51–7.47 (m, 1H), 7.26–7.23 (m, 3H), 7.10–7.05 (m,
32
22
2
2
7H), 6.96–6.93 (m, 2H), 6.68 (d, J = 9.2 Hz, 1H), 5.25 (s, 1H),
+
13
[
M + H] 501.13643; found: 501.13649.
2.20 (s, 3H). C NMR (150 MHz, CDCl ) δ 197.2, 171.8, 150.3,
3
1
1
1
41.9, 141.4, 136.3, 132.4, 131.0, 130.3, 130.0, 129.4, 129.2,
29.1, 128.9, 128.7, 128.6, 128.3, 127.9, 127.0, 125.6, 123.2,
4
.2.4. 4'-(4-chlorophenyl)-2',5'-diphenyl-2',4'-
dihydro-3H-spiro[naphtho[2,3-b]furan-2,3'-
pyrazol] -3-one (3d)
22.1, 115.9, 115.5, 113.2, 113.1, 103.0, 59.8, 19.4; HRMS(ESI)
+
o
1
calcd. for C33
H
25
N
2
O
2
[M + H] 481.19105; found: 481.19149.
Yellow solid; 51 mg, 85% yield; mp 188–190 C; H NMR
(
600 MHz, cdcl ) δ 8.80 (d, J = 7.8 Hz, 1H), 7.94 (d, J = 9.0 Hz,
4.2.9. 2',5'-diphenyl-4'-(m-tolyl)-2',4'-dihydro-3H-
3
1
3
7
H), 7.79 (d, J = 7.8 Hz, 1H), 7.74–7.71 (m, 1H), 7.53–7.50 (m,
H), 7.30–7.28 (m, 2H), 7.27–7.24 (m, 1H), 7.14–7.13 (m, 4H),
.06–7.04 (m, 2H), 7.00–6.98 (m, 2H), 6.91–6.89 (m, 1H), 6.72
spiro[naphtho[2,3-b] furan-2,3'-pyrazol] -3-one (3i)
o
1
Yellow solid; 52 mg, 90% yield; mp 172–174 C; H NMR
(600 MHz, CDCl ) δ 8.81 (d, J = 8.4 Hz, 1H), 7.90 (d, J = 9.0
3
13
(d, J = 9.0 Hz, 1H), 5.24 (s, 1H). C NMR (100 MHz, CDCl ) δ
Hz, 1H), 7.76 (d, J = 8.4 Hz, 1H), 7.71 (t, J = 7.8 Hz, 1H), 7.58–
7.56 (m, 2H), 7.49 (t, J = 7.8 Hz, 1H), 7.27–7.23 (m, 3H), 7.16–
7.12 (m, 4H), 6.95–6.83 (m, 5H), 6.69 (d, J = 9.0 Hz, 1H), 5.21
3
1
1
1
96.6, 171.9, 149.2, 141.7, 141.6, 134.0, 131.5, 130.7, 130.4,
29.6, 129.2, 129.1, 129.1, 128.8, 128.5, 128.4, 128.4, 127.0,
25.9, 123.3, 122.3, 116.1, 113.1, 113.0, 1+ 03.0, 63.2;
13
(s, 1H), 2.06 (s, 3H). C NMR (150 MHz, CDCl ) δ 197.0,
3
HRMS(ESI) calcd. for C H ClN O [M + H] 501.13643;
found: 501.13644.
172.1, 149.8, 141.8, 141.3, 137.6, 131.1, 130.8, 130.8, 130.2,
129.1, 129.1, 128.9, 128.7, 128.6, 128.6, 128.3, 127.9, 127.3,
32
22
2
2
1
27.1, 125.7, 123.3, 122.1, 116.1, 113.2, 113.2, 103.3, 64.0, 21.1;
4
.2.5. 4'-(4-bromophenyl)-2',5'-diphenyl-2',4'-
+
HRMS(ESI) calcd. for C H N O [M + H] 481.19105; found:
3
33
25
2
2
dihydro-3H-spiro[naphtho[2,3-b]furan-2,3'-
pyrazol] -3-one (3e)
03. 481.19109.
o
1
Yellow solid; 56 mg, 86% yield; mp 180–182 C; H NMR
4.2.10. 2',5'-diphenyl-4'-(p-tolyl)-2',4'-dihydro-3H-
(
600 MHz, CDCl ) δ 8.81 (d, J = 7.8 Hz, 1H), 7.96 (d, J = 9.0
spiro[naphtho[2,3-b] furan-2,3'-pyrazol] -3-one (3j)
3
o
1
Hz, 1H), 7.81 (d, J = 8.4 Hz, 1H), 7.74 (t, J = 7.2 Hz, 1H), 7.54–
.51 (m, 3H), 7.30–7.28 (m, 3H), 7.22 (d, J = 8.4 Hz, 2H), 7.15
d, J = 4.2 Hz, 4H), 6.95–6.90 (m, 3H), 6.74 (d, J = 9.0 Hz, 1H),
Yellow solid; 53 mg, 92% yield; mp 171–173 C; H NMR
7
(
5
1
1
1
(600 MHz, CDCl ) δ 8.81 (d, J = 8.4 Hz, 1H), 7.91 (d, J = 9.0
3
Hz, 1H), 7.77 (d, J = 7.8 Hz, 1H), 7.73–7.70 (m, 1H), 7.57–7.55
(m, 2H), 7.51–7.48 (m, 1H), 7.28–7.23 (m, 3H), 7.15–7.11 (m,
4H), 6.93–6.85 (m, 5H), 6.71 (d, J = 9.0 Hz, 1H), 5.23 (s, 1H),
13
.24 (s, 1H). C NMR (150 MHz, CDCl ) δ 196.6, 172.0, 149.1,
3
41.7, 141.7, 131.8, 131.3, 130.7, 130.4, 130.2, 129.3, 129.1,
29.1, 128.8, 128.5, 128.4, 127.0, 125.9, 123.3, 122.4, 122.2,
13
2.17 (s, 3H). C NMR (150 MHz, CDCl ) δ 197.1, 172.1, 149.9,
3
16.2, 113.1, 113.0, 103.0, 63.2; HRMS(ESI) calcd. for
1
41.9, 141.3, 137.7, 131.2, 130.2, 130.1, 129.2, 129.1, 128.9,
128.8, 128.6, 128.6, 128.3, 127.9, 127.1, 125.7, 123.3, 122.1,
16.1, 113.3, 113.1, 103.3, 63.8, 21.1; HRMS(ESI) calcd. for
+
C H BrN O [M + H] 545.08592; found: 545.08588.
32
22
2
2
1
4
.2.6. 4'-(4-fluorophenyl)-2',5'-diphenyl-2',4'-
+
C H N O [M + H] 481.19105; found: 481.19109.
33
25
2
2
dihydro-3H-spiro[naphtho[2,3-b]furan-2,3'-
pyrazol] -3-one (3f)
4
.2.11. 4'-(4-methoxyphenyl)-2',5'-diphenyl-2',4'-
o
1
Yellow solid; 48 mg, 83% yield; mp 195–197 C; H NMR
dihydro-3H-spiro[naphtho[2,3-b]furan-2,3'-
(
600 MHz, CDCl ) δ 8.81 (d, J = 8.4 Hz, 1H), 7.95 (d, J = 9.0
pyrazol] -3-one (3k)
3
Hz, 1H), 7.80 (d, J = 8.4 Hz, 1H), 7.75–7.72 (m, 1H), 7.55–7.51

6
Tetrahedron
o
1
Yellow solid; 56 mg, 94% yield; mp 158–160 C; H NMR
600 MHz, CDCl ) δ 8.81 (d, J = 7.8 Hz, 1H), 7.92 (d, J = 9.0
113.3, 112.6, 106.3, 65.4, 34.3, 29.7; HRMS(ESI) calcd. for
+
(
C H N O [M + H] 447.20670; found: 447.20590.
30 27
3
2
2
Hz, 1H), 7.77 (d, J = 7.8 Hz, 1H), 7.73–7.70 (m, 1H), 7.57–7.55
m, 2H), 7.51–7.48 (m, 1H), 7.27–7.24 (m, 3H), 7.15–7.12 (m,
4
.2.16. 6-bromo-2',4',5'-triphenyl-2',4'-dihydro-3H-
(
spiro[naphtho[2,3-b] furan-2,3'-pyrazol] -3-one (3p)
4
H), 6.96 (d, J = 7.8 Hz, 2H), 6.90–6.87 (m, 1H), 6.73 (d, J = 9.0
o
1
13
Yellow solid; 57 mg, 88% yield; mp 178–180 C; H NMR
Hz, 1H), 6.59 (d, J = 7.8 Hz, 2H), 5.22 (s, 1H), 3.65 (s, 3H).
C
(600 MHz, CDCl ) δ 8.80 (d, J = 8.4 Hz, 1H), 7.93 (d, J = 9.0
3
NMR (150 MHz, CDCl ) δ 197.1, 172.1, 159.1, 149.9, 141.9,
3
Hz, 1H), 7.78 (d, J = 7.8 Hz, 1H), 7.75–7.72 (m, 1H), 7.76 –7.55
m, 1H), 7.53–7.50 (m, 1H), 7.31–7.23 (m, 5H), 7.13–7.10 (m,
H), 7.07 (t, J = 7.8 Hz, 2H), 7.04–7.01 (m, 4H), 6.69 (d, J = 9.0
1
1
1
41.4, 131.4, 131.1, 130.2, 129.2, 129.1, 128.9, 128.7, 128.6,
28.3, 127.1, 125.7, 123.3, 122.9, 122.1, 116.0, 113.5, 113.3,
13.1, 103.3, 63.5, 55.1; HRMS(ESI) calcd. for C H N O [M +
(
1
33
25
2
3
13
+
Hz, 1H), 5.26 (s, 1H). C NMR (150 MHz, CDCl ) δ 196.6,
3
H] 497.18597; found: 497.18587.
1
72.0, 149.1, 141.7, 141.7, 131.8, 131.3, 130.7, 130.4, 130.2,
129.3, 129.1, 129.1, 128.8, 128.5, 128.4, 127.1, 125.9, 123.3,
22.4, 122.2, 116.2, 113.1, 113.0, 103.0, 63.2; HRMS(ESI)
4
.2.12. 4'-(naphthalen-2-yl)-2',5'-diphenyl-2',4'-
dihydro-3H-spiro[naphtho[2,3-b]furan-2,3'-
1
+
pyrazol] -3-one (3l)
calcd. for C H BrN O [M + H] 545.08592; found: 545.08573.
32
22
2
2
o
1
Yellow solid; 56 mg, 90% yield; mp 195–197 C; H NMR
4
3
.2.17. 7-methoxy-2',4',5'-triphenyl-2',4'-dihydro-
H-spiro[naphtho[2,3-b]furan-2,3'-pyrazol] - 3-one
(
600 MHz, CDCl ) δ 8.84 (d, J = 8.4 Hz, 1H), 7.77 (d, J = 9.0
3
Hz, 1H), 7.73–7.69 (m, 3H), 7.60–7.56 (m, 5H), 7.49–7.46 (m,
(
3q)
1
6
H), 7.41–7.38 (m, 1H), 7.36–7.33 (m, 1H), 7.26–7.14 (m, 8H),
o
1
13
Yellow solid; 53 mg, 90% yield; mp 186–188 C; H NMR
.93–6.90 (m, 1H), 6.60 (d, J = 9.0 Hz, 1H), 5.45 (s, 1H).
C
(400 MHz, CDCl ) δ 8.81 (d, J = 8.4 Hz, 1H), 7.90 (d, J = 8.8
3
NMR (150 MHz, CDCl ) δ 197.0, 172.1, 149.7, 141.8, 141.5,
3
Hz, 1H), 7.76 (d, J = 8.4 Hz, 1H), 7.71 (t, J = 7.6 Hz, 1H), 7.58–
.56 (m, 2H), 7.50–7.46 (m, 1H), 7.26–7.23 (m, 3H), 7.17–7.10
m, 4H), 6.96 (t, J = 8.0 Hz, 1H), 6.90–6.86 (m, 1H), 6.71 (d, J =
8.8 Hz, 1H), 6.65–6.63 (m, 2H), 6.56 (s, 1H), 5.24 (s, 1H), 3.46
1
1
1
32.8, 132.8, 131.1, 130.2, 129.3, 129.2, 129.1, 128.9, 128.8,
28.6, 128.5, 128.3, 127.9, 127.9, 127.7, 127.5, 127.0, 126.2,
7
(
26.0, 125.7, 123.3, 122.3, 116.3, 113.1, 113.0, 103.5, 64.0;
+
HRMS(ESI) calcd. for C H N O [M + H] 517.19105; found:
36
25
2
2
13
(s, 3H). C NMR (150 MHz, CDCl ) δ 196.7, 170.9, 156.7,
3
5
17.19107.
1
49.6, 141.9, 140.3, 132.5, 131.3, 130.0, 129.1, 129.0, 128.8,
128.7, 128.7, 128.3, 127.1, 125.5, 123.2, 121.8, 120.1, 115.6,
13.6, 113.3, 109.5, 102.9, 57.0, 54.8; HRMS(ESI) calcd. for
4
3
.2.13. 4'-(furan-2-yl)-2',5'-diphenyl-2',4'-dihydro-
H-spiro[naphtho[2,3-b]furan-2,3'-pyrazol] -3-one
1
+
(
3m)
C H N O [M + H] 497.18597; found: 497.18596.
33
25
2
3
o
1
Yellow solid; 40 mg, 73% yield; mp 178–180 C; H NMR
4
.2.18. 5'-(2-chlorophenyl)-2',4'-diphenyl-2',4'-
(
600 MHz, CDCl ) δ 8.82 (d, J = 8.4 Hz, 1H), 8.04 (d, J = 9.0
3
dihydro-3H-spiro[naphtho[2,3-b]furan-2,3'-
pyrazol] -3-one (3r)
Hz, 1H), 7.83 (d, J = 8.4 Hz, 1H), 7.74 (t, J = 7.2 Hz, 1H), 7.60–
.58 (m, 2H), 7.53 (t, J = 7.2 Hz, 1H), 7.33–7.30 (m, 3H), 7.22
s, 1H), 7.14 (d, J = 4.2 Hz, 4H), 6.93–6.89 (m, 2H), 6.15–6.14
7
o
1
Yellow solid; 44 mg, 73% yield; mp 198–200 C; H NMR
(
(
13
(600 MHz, CDCl ) δ 8.79 (d, J = 7.8 Hz, 1H), 7.95 (d, J = 9.0
Hz, 1H), 7.79 (d, J = 8.4 Hz, 1H), 7.73–7.70 (m, 1H), 7.52–7.49
3
m, 1H), 6.11–6.10 (m, 1H), 5.42 (s, 1H). C NMR (150 MHz,
CDCl ) δ 196.4, 172.6, 147.5, 144.8, 143.1, 141.6, 141.6, 131.1,
3
(m, 3H), 7.28–7.24 (m, 3H), 7.20 (d, J = 8.4 Hz, 2H), 7.13 (d, J =
1
1
30.4, 129.3, 129.2, 129.1, 128.7, 128.7, 128.4, 126.5, 125.8,
4
.2 Hz, 4H), 6.92 (d, J = 7.8 Hz, 2H), 6.90–6.89 (m, 1H), 6.72 (d,
23.4, 122.4, 116.4, 113.3, 112.7, 111.3, 110.5, 102.8, 57.0;
13
+
J = 9.0 Hz, 1H), 5.22 (s, 1H). C NMR (150 MHz, CDCl ) δ
1
1
127.0, 126.4, 125.8, 123.5, 122.1, 115.9, 113.5, 112.9, 102.4,
5
3
HRMS(ESI) calcd. for C H N O [M + H] 457.15467; found:
30
21
2
3
96.3, 171.2, 149.2, 141.7, 141.2, 134.4, 133.4, 130.7, 130.3,
29.6, 129.3, 129.3, 129.1, 129.0, 129.0, 128.8, 128.6, 128.4,
4
57.15433.
4
.2.14. 2',5'-diphenyl-4'-(thiophen-2-yl)-2',4'-
+
dihydro-3H-spiro[naphtho[2,3-b]furan-2,3'-
9.6; HRMS(ESI) calcd. for C H ClN O [M + H] 501.13643;
32 22 2 2
pyrazol] -3-one (3n)
found: 501.13647.
o
1
Yellow solid; 41 mg, 72% yield; mp 174–176 C; H NMR
4
.2.19. 5'-(3-chlorophenyl)-2',4'-diphenyl-2',4'-
(
600 MHz, CDCl ) δ 8.82 (d, J = 8.4 Hz, 1H), 7.97 (d, J = 9.0
3
dihydro-3H-spiro[naphtho[2,3-b]furan-2,3'-
pyrazol] -3-one (3s)
Hz, 1H), 7.80 (d, J = 7.8 Hz, 1H), 7.73 (t, J = 7.2 Hz, 1H), 7.60–
.58 (m, 2H), 7.52 (t, J = 7.2 Hz, 1H), 7.30–7.27 (m, 3H), 7.15
d, J = 4.2 Hz, 4H), 7.07–7.05 (m, 1H), 6.95 (d, J = 1.7 Hz, 1H),
7
(
o
1
Yellow solid; 46 mg, 77% yield; mp 154–156 C; H NMR
(600 MHz, CDCl ) δ 8.81 (d, J = 8.4 Hz, 1H), 7.92 (d, J = 9.0
3
6
.92–6.89 (m, 1H), 6.80–6.78 (m, 2H), 5.39 (s, 1H), 5.30 (s, 1H).
1
3
Hz, 1H), 7.78 (d, J = 7.8 Hz, 1H), 7.74–7.72 (m, 2H), 7.52–7.50
m, 1H), 7.26–7.24 (m, 2H), 7.16–7.12 (m, 6H), 7.09 (t, J = 7.2
Hz, 2H), 7.04–7.03 (m, 2H), 6.93–6.91 (m, 1H), 6.69 (d, J = 8.4
C NMR (150 MHz, CDCl ) δ 196.7, 172.2, 149.5, 141.8, 141.5,
3
(
1
1
1
4
31.1, 131.1, 130.3, 129.2, 129.1, 129.1, 129.0, 128.7, 128.6,
28.3, 126.9, 125.8, 125.4, 125.3, 123.3, 122.2, 116.0, 113.2,
13
+
Hz, 1H), 5.22 (s, 1H). C NMR (150 MHz, CDCl ) δ 196.6,
1
1
3
13.1, 103.2, 58.9; HRMS(ESI) calcd. for C H N O S [M + H]
30
21
2
2
72.1, 150.3, 141.6, 141.4, 136.3, 135.3, 130.8, 130.3, 130.2,
29.2, 129.1, 128.7, 128.6, 128.6, 128.4, 128.1, 128.1, 126.7,
73.13183; found: 473.13187.
4
3
.2.15. 4'-(tert-butyl)-2',5'-diphenyl-2',4'-dihydro-
H-spiro[naphtho[2,3-b]furan-2,3'-pyrazol] -3-one
125.7, 123.3, 122.4, 119.4, 116.2, 113.2, 113.1, 103.1, 63.5;
+
HRMS(ESI) calcd. for C H ClN O [M + H] 501.13643;
32
22
2
2
(
3o)
found: 501.13620.
o
1
Yellow solid; 37 mg, 69% yield; mp 194–196 C; H NMR
4
.2.20. 5'-(4-chlorophenyl)-2',4'-diphenyl-2',4'-
(400 MHz, CDCl ) δ 8.75 (d, J = 8.4 Hz, 1H), 8.11 (d, J = 9.2
3
dihydro-3H-spiro[naphtho[2,3-b]furan-2,3'-
Hz, 1H), 7.84 (d, J = 8.0 Hz, 1H), 7.72–7.68 (m, 1H), 7.61–7.58
m, 2H), 7.53–7.49 (m, 1H), 7.44–7.40 (m, 3H), 7.17 (d, J = 8.8
Hz, 1H), 7.14–7.12 (m, 2H), 7.05–7.01 (m, 2H), 6.88–6.84 (m,
pyrazol] -3-one (3t)
(
o
1
Yellow solid; 50 mg, 83% yield; mp 193–195 C; H NMR
13
(600 MHz, CDCl ) δ 8.81 (d, J = 8.4 Hz, 1H), 7.91 (d, J = 9.0
3
1
1
1
H), 4.04 (s, 1H), 0.99 (s, 9H). C NMR (150 MHz, CDCl ) δ
3
Hz, 1H), 7.78 (d, J = 8.4 Hz, 1H), 7.74–7.72 (m, 1H), 7.52–7.51
98.8, 173.2, 153.7, 142.1, 141.3, 135.1, 130.3, 129.4, 128.9,
28.7, 128.7, 128.7, 128.6, 128.1, 125.7, 123.4, 123.3, 119.6,
(m, 1H), 7.50–7.48 (m, 2H), 7.24–7.22 (m, 2H), 7.15–7.11 (m,

7
+
5
H), 7.08 (t, J = 7.2 Hz, 2H), 7.03 (d, J = 7.2 Hz, 2H), 6.94–6.90
HRMS(ESI) calcd. for C H N O [M + H] 497.18597, found:
33 25 2 3
497.18587.
13
(m, 1H), 6.69 (d, J = 9.0 Hz, 1H), 5.23 (s, 1H). C NMR (150
MHz, CDCl ) δ 196.6, 172.0, 148.3, 141.5, 134.4, 132.9, 130.5,
3
4
.2.25. 5'-(3-methoxyphenyl)-2',4'-diphenyl-2',4'-
1
1
6
30.3, 130.1, 129.5, 129.2, 129.2, 128.9, 128.7, 128.5, 128.2,
26.8, 125.8, 125.2, 123.3, 122.5, 116.2, 113.1, 113.1, 103.1,
dihydro-3H-spiro[naphtho[2,3-b]furan-2,3'-
pyrazol] -3-one (3y)
+
3.8; HRMS(ESI) calcd. for C H ClN O [M + H] 501.13643;
32
22
2
2
o
1
Yellow solid; 49 mg, 82% yield; mp 156–158 C; H NMR
found: 501.13643.
(600 MHz, CDCl ) δ 8.82 (d, J = 7.8 Hz, 1H), 7.91 (d, J = 9.0
3
4
.2.21. 5'-(4-bromophenyl)-2',4'-diphenyl-2',4'-
Hz, 1H), 7.77 (d, J = 8.4 Hz, 1H), 7.74–7.71 (m, 1H), 7.52–7.49
(m, 1H), 7.18–7.14 (m, 6H), 7.11–7.05 (m, 6H), 6.92–6.89 (m,
dihydro-3H-spiro[naphtho[2,3-b]furan-2,3'-
pyrazol] -3-one (3u)
1
H), 6.84–6.83 (m, 1H), 6.70 (d, J = 9.0 Hz, 1H), 5.25 (s, 1H),
o
1
13
Yellow solid; 55 mg, 84% yield; mp 179–181 C; H NMR
3.71 (s, 3H). C NMR (150 MHz, CDCl ) δ 196.9, 172.0, 159.4,
3
(
600 MHz, CDCCl ) δ 8.81 (d, J = 7.8 Hz, 1H), 7.91 (d, J = 9.0
149.6, 141.8, 141.4, 132.3, 131.1, 130.2, 129.3, 129.2, 129.1,
129.1, 128.7, 128.6, 128.1, 128.0, 125.7, 123.3, 122.2, 119.8,
116.1, 115.3, 113.2, 113.1, 111.8, 103.2, 64.1, 55.1; HRMS(ESI)
3
Hz, 1H), 7.78 (d, J = 8.4 Hz, 1H), 7.74–7.72 (m, 1H), 7.52–7.50
m, 1H), 7.43–7.41 (m, 2H), 7.39–7.38 (m, 2H), 7.15–7.12 (m,
H), 7.08 (t, J = 7.2 Hz, 2H), 7.03 (d, J = 7.2 Hz, 2H), 6.93–6.90
(
5
+
calcd. for C H N O [M + H] 497.18597; found: 497.18596.
33
25
2
3
13
(m, 1H), 6.69 (d, J = 9.0 Hz, 1H), 5.23 (s, 1H). C NMR (150
4
.2.26. 5'-(4-methoxyphenyl)-2',4'-diphenyl-2',4'-
MHz, CDCl ) δ 196.7, 172.0, 148.6, 141.6, 141.5, 131.5, 130.6,
1
1
6
3
dihydro-3H-spiro[naphtho[2,3-b]furan-2,3'-
30.3, 130.2, 130.1, 130.0, 129.2, 129.1, 128.7, 128.5, 128.5,
28.2, 128.2, 125.8, 123.3, 123.2, 122.4, 116.1, 113.1, 103.1,
pyrazol] -3-one (3z)
o
1
+
Yellow solid; 53 mg, 89% yield; mp 179–181 C; H NMR
3.8; HRMS(ESI) calcd. for C H BrN O [M + H] 545.08592;
32
22
2
2
(
600 MHz, CDCl ) δ 8.82 (d, J = 8.4 Hz, 1H), 7.90 (d, J = 9.0
3
found: 545.08573.
Hz, 1H), 7.77 (d, J = 7.8 Hz, 1H), 7.74–7.71 (m, 1H), 7.51–7.49
(m, 3H), 7.14–7.10 (m, 5H), 7.08–7.04 (m, 4H), 6.90–6.87 (m,
1H), 6.79 (d, J = 9.0 Hz, 2H), 6.68 (d, J = 9.0 Hz, 1H), 5.24 (s,
4
.2.22. 5'-(4-fluorophenyl)-2',4'-diphenyl-2',4'-
dihydro-3H-spiro[naphtho[2,3-b]furan-2,3'-
pyrazol] -3-one (3v)
13
1
H), 3.78 (s, 3H). C NMR (150 MHz, CDCl ) δ 197.0, 172.0,
3
o
1
Yellow solid; 50 mg, 86% yield; mp 198–200 C; H NMR
160.2, 149.5, 142.0, 141.3, 131.2, 130.3, 130.2, 129.1, 129.1,
129.1, 128.6, 128.6, 128.6, 128.1, 128.0, 128.0, 125.7, 123.7,
123.3, 121.9, 115.9, 113.8, 113.2, 103.3, 64.2, 55.2; HRMS(ESI)
(600 MHz,CDCl ) δ 8.82 (d, J = 7.8 Hz, 1H), 7.91 (d, J = 9.0 Hz,
3
1
2
2
1
H), 7.78 (d, J = 7.8 Hz, 1H), 7.74–7.71 (m, 1H), 7.55–7.53 (m,
H), 7.52–7.49 (m, 1H), 7.15–7.11 (m, 5H), 7.08 (t, J = 7.2 Hz,
H), 7.03 (d, J = 7.2 Hz, 2H), 6.97–6.94 (m, 2H), 6.92–6.89 (m,
+
calcd. for C H N O [M + H] 497.18597; found: 497.18601.
33
25
2
3
13
4.2.27. 2',4'-diphenyl-5'-(p-tolyl)-2',4'-dihydro-3H-
spiro[naphtho[2,3-b] furan-2,3'-pyrazol] -3-one
H), 6.69 (d, J = 9.0 Hz, 1H), 5.23 (s, 1H). C NMR (150 MHz,
CDCl ) δ 196.8, 172.0, 163.1 (d, J = 247.5 Hz), 148.7, 141.7,
3
(
3aa)
1
1
1
41.4, 130.8, 130.3, 130.2, 129.2., 129.1, 129.0, 128.9, 128.7,
28.6, 128.2, 128.1, 127.3 (d, J = 3.0 Hz), 125.8, 123.3, 122.3,
o
1
Yellow solid; 51 mg, 88% yield; mp 195–197 C; H NMR
(
600 MHz, CDCl ) δ 8.82 (d, J = 8.4 Hz, 1H), 7.90 (d, J = 9.0
3
16.1, 115.5 (d, J = 22.5 Hz), 113.1, 103.2, 64.0; HRMS(ESI)
+
Hz, 1H), 7.77 (d, J = 8.4 Hz, 1H), 7.74–7.71 (m, 1H), 7.52–7.49
m, 1H), 7.45 (d, J = 8.4 Hz, 2H), 7.15–7.09 (m, 5H), 7.07–7.03
(m, 6H), 6.90–6.88 (m, 1H), 6.68 (d, J = 9.0 Hz, 1H), 5.25 (s,
calcd. for C H FN O [M + H] 485.16598; found: 485.16609.
32
22
2
2
(
4
.2.23. 2',4'-diphenyl-5'-(4-
trifluoromethyl)phenyl)-2',4'-dihydro-3H-
spiro[naphtho[2,3-b] furan-2,3'-pyrazol] -3-one (3w)
13
(
1H), 2.31 (s, 3H). C NMR (150 MHz, CDCl ) δ 197.0, 172.0,
3
1
49.8, 141.9, 141.3, 139.1, 131.1, 130.2, 130.2, 129.1, 129.1,
o
1
Yellow solid; 53 mg, 83% yield; mp 172–174 C; H NMR
129.0, 129.0, 128.7, 128.6, 128.2, 128.0, 127.9, 127.1, 125.7,
123.3, 122.0, 116.0, 113.2, 103.3, 64.1, 21.4; HRMS(ESI) calcd.
(600 MHz, CDCl ) δ 8.83 (d, J = 8.4 Hz, 1H), 7.93 (d, J = 9.0
3
+
Hz, 1H), 7.79 (d, J = 8.4 Hz, 1H), 7.76–7.73 (m, 1H), 7.67 (d, J =
for C H N O [M + H] 481.19105; found: 481.19149.
33
25
2
2
8
7
6
.4 Hz, 2H), 7.53–7.51 (m, 3H), 7.19–7.14 (m, 4H), 7.15 (d, J =
.2 Hz, 1H), 7.10 (t, J = 7.2 Hz, 2H), 7.05 (d, J = 7.2 Hz, 2H),
4
.2.28. 2',4'-diphenyl-5'-(pyridin-2-yl)-2',4'-
13
dihydro-3H-spiro[naphtho[2,3-b]furan-2,3'-
pyrazol] -3-one (3ab)
.95–6.93 (m, 1H), 6.70 (d, J = 9.0 Hz, 1H), 5.28 (s, 1H).
C
NMR (150 MHz, CDCl ) δ 196.5, 172.0, 148.1, 141.6, 141.4,
1
1
1
3
o
1
Yellow solid; 41 mg, 73% yield; mp 174–176 C; H NMR
34.5, 130.5, 130.4 (q, J = 33.0 Hz ), 130.3, 130.1, 129.2, 129.2,
28.7, 128.5, 128.3, 128.3, 127.1, 125.9, 125.3 (q, J = 3.0 Hz ),
24.0 (q, J = 270.0 Hz ), 123.3, 122.7, 116.2, 113.1, 113.1, 103.1,
(600 MHz, CDCl ) δ 8.82 (d, J = 7.8 Hz, 1H), 8.40–8.38 (m, 1H),
3
7
.98–7.96 (m, 1H), 7.92 (d, J = 9.0 Hz, 1H), 7.78 (d, J = 8.4 Hz,
+
1H), 7.74–7.71 (m, 1H), 7.69–7.66 (m, 1H), 7.52–7.50 (m, 1H),
7
6
6
3.7; HRMS(ESI) calcd. for C H F N O [M + H] 535.16279;
33
22
3
2
2
.18–7.13 (m, 5H), 7.10–7.06 (m, 1H), 7.04–6.99 (m, 4H), 6.93–
13
.90 (m, 1H), 6.68 (d, J = 9.0 Hz, 1H), 5.44 (s, 1H). C NMR
found: 535.16283.
4
.2.24. 5'-(2-methoxyphenyl)-2',4'-diphenyl-2',4'-
(150 MHz, CDCl ) δ 196.8, 172.0, 150.6, 150.5, 149.3, 141.5,
141.3, 136.0, 131.7, 130.2, 129.7, 129.2, 129.1, 128.7, 128.6,
3
dihydro-3H-spiro[naphtho[2,3-b]furan-2,3'-
pyrazol] -3-one (3x)
1
27.7, 127.4, 125.7, 123.4, 123.0, 122.5, 121.9, 116.2, 113.2,
o
1
+
Yellow solid; 43 mg, 72% yield; mp 197–199 C; H NMR
113.1, 103.1, 63.7; HRMS(ESI) calcd. for C H N O [M + H]
31 22 3 2
(
400 MHz, CDCl ) δ 8.87 (d, J = 8.4 Hz, 1H), 7.90 (d, J = 9.2
468.17065; found: 468.17061.
3
Hz, 1H), 7.79 (d, J = 8.4 Hz, 1H), 7.74–7.70 (m, 1H), 7.61–7.59
m, 2H), 7.52–7.48 (m, 1H), 7.29–7.26 (m, 4H), 7.15 (d, J = 4.4
4
3
.2.29. 5'-(furan-2-yl)-2',4'-diphenyl-2',4'-dihydro-
H-spiro[naphtho[2,3-b]furan-2,3'-pyrazol] -3-one
(
Hz, 4H), 7.10–7.05 (m, 1H), 6.90–6.86 (m, 1H), 6.75 (t, J = 7.6
Hz 1H), 6.65 (d, J = 9.2 Hz, 1H), 6.40 (d, J = 8.0 Hz, 1H), 5.77
(
3ac)
o
1
13
Yellow solid; 42 mg, 77% yield; mp 182–184 C; H NMR
(
s, 1H), 3.05 (s, 3H). C NMR (150 MHz, CDCl ) δ 196.9,
3
(600 MHz, CDCl ) δ 8.79 (d, J = 8.4 Hz, 1H), 7.91 (d, J = 9.0
3
1
1
1
72.1, 159.1, 149.6, 141.8, 141.4, 132.4, 131.1, 130.3, 129.1,
29.1, 129.0, 129.0, 128.7, 128.6, 128.3, 127.0, 125.7, 123.2,
22.7, 122.2, 116.0, 115.4, 114.1, 113.2, 113.1, 103.2, 63.9, 55.0;
Hz, 1H), 7.76 (d, J = 8.4 Hz, 1H), 7.72–7.70 (m, 1H), 7.50–7.48
m, 2H), 7.19–7.12 (m, 9H), 6.92–6.89 (m, 1H), 6.74 (d, J = 9.0
Hz, 1H), 6.30 (dd, J = 3.0, 1.2 Hz, 1H), 5.92 (d, J = 3.0 Hz, 1H),
(

8
Tetrahedron
13
5
.13 (s, 1H). C NMR (150 MHz, CDCl ) δ 196.3, 172.1,
4.2.34. 2'-(4-bromophenyl)-4',5'-diphenyl-2',4'-
dihydro-3H-spiro[naphtho[2,3-b]furan-2,3'-
pyrazol] -3-one (3ah)
3
1
1
1
46.4, 143.8, 142.1, 141.6, 141.4, 130.5, 130.3, 130.2, 129.2,
29.0, 128.7, 128.6, 128.3, 128.0, 125.7, 123.3, 122.5, 116.6,
13.2, 113.0, 112.2, 111.3, 102.8, 63.9; HRMS(ESI) calcd. for
o
1
Yellow solid; 54 mg, 83% yield; mp 173–175 C; H NMR
(600 MHz, CDCl ) δ 8.80 (d, J = 8.4 Hz, 1H), 7.92 (d, J = 9.0
+
C H N O [M + H] 457.15467; found: 457.15427.
30
22
2
3
3
Hz, 1H), 7.78 (d, J = 7.8 Hz, 1H), 7.74–7.71 (m, 1H), 7.55–7.54
4
.2.30. 2',4'-diphenyl-5'-(thiophen-2-yl)-2',4'-
(m, 2H), 7.52–7.50 (m, 1H), 7.30–7.22 (m, 5H), 7.12–7.10 (m,
dihydro-3H-spiro[naphtho[2,3-b]furan-2,3'-
pyrazol] -3-one (3ad)
1
H), 7.06 (t, J = 7.8 Hz, 2H), 7.03–7.00 (m, 4H), 6.68 (d, J = 9.0
13
o
1
Hz, 1H), 5.25 (s, 1H). C NMR (150 MHz, CDCl
3
) δ 196.6,
Yellow solid; 46 mg, 81% yield; mp 193–195 C; H NMR
1
1
1
72.0, 150.3, 141.6, 140.9, 132.0, 130.8, 130.8, 130.4, 130.2,
29.2, 129.2, 128.7, 128.5, 128.4, 128.1, 128.1, 127.1, 125.9,
(600 MHz, CDCl ) δ 8.80 (d, J = 7.8 Hz, 1H), 7.91 (d, J = 9.0
3
Hz, 1H), 7.77 (d, J = 8.4 Hz, 1H), 7.72 (t, J = 7.2 Hz, 1H), 7.50
t, J = 7.2 Hz, 1H), 7.27 (d, J = 4.8 Hz, 1H), 7.18–7.12 (m, 9H),
23.3, 117.6, 114.6, 113.0, 113.0, 102.9, 64.1; HRMS(ESI)
(
6
6
+
calcd. for C H BrN O [M + H] 545.08592; found: 545.08608.
32
22
2
2
.91–6.89 (m, 1H), 6.83–6.82 (m, 1H), 6.73 (d, J = 9.0 Hz, 1H),
13
.58 (d, J = 3.6 Hz, 1H), 5.18 (s, 1H). C NMR (150 MHz,
4.2.35. 4',5'-diphenyl-2'-(p-tolyl)-2',4'-dihydro-3H-
spiro[naphtho[2,3-b] furan-2,3'-pyrazol] -3-one
(3ai)
CDCl ) δ 196.4, 172.1, 145.8, 141.6, 141.4, 134.6, 130.5, 130.2,
1
1
3
29.2, 129.1, 128.7, 128.6, 128.3, 128.1, 127.8, 127.3, 127.1,
o
1
25.7, 123.3, 122.3, 116.3, 113.2, 113.0, 110.0, 103.2, 64.7;
Yellow solid; 50 mg, 87% yield; mp 168–170 C; H NMR
+
HRMS(ESI) calcd. for C H N O S [M + H] 473.13183, found:
(400 MHz, CDCl ) δ 8.81 (d, J = 8.4 Hz, 1H), 7.89 (d, J = 8.8
30
21
2
2
3
4
73.13184.
Hz, 1H), 7.76 (d, J = 8.0 Hz, 1H), 7.74–7.70 (m, 1H), 7.56–7.54
(
7
2
m, 2H), 7.51–7.47 (m, 1H), 7.26–7.23 (m, 3H), 7.10–7.05 (m,
4
3
.2.31. 5'-cyclohexyl-2',4'-diphenyl-2',4'-dihydro-
H-spiro[naphtho[2,3-b]furan-2,3'-pyrazol] -3-one
H), 6.96–6.93 (m, 2H), 6.68 (d, J = 9.2 Hz, 1H), 5.25 (s, 1H),
13
.20 (s, 3H). C NMR (150 MHz, CDCl ) δ 197.0, 172.1, 149.4,
3
(
3ae)
o
1
141.3, 139.5, 131.9, 131.2, 131.1, 130.2, 130.2, 129.6, 129.1,
1
1
Yellow solid;37 mg, 65% yield; mp 160–162 C; H NMR
28.8, 128.6, 128.6, 128.3, 128.1, 128.1, 127.9, 127.0, 125.6,
(600 MHz, CDCl ) δ 8.79 (d, J = 7.8 Hz, 1H), 7.87 (d, J = 9.0
3
23.3, 116.6, 113.2, 103.7, 63.9, 20.6; HRMS(ESI) calcd. for
Hz, 1H), 7.73 (d, J = 8.4 Hz, 1H), 7.70–7.68 (m, 1H), 7.48–7.45
m, 1H), 7.16–7.15 (m, 3H), 7.13–7.09 (m, 4H), 7.07–7.05 (m,
+
C H N O [M + H] 481.19105; found: 481.19088.
33
25
2
2
(
2
2
1
1
1
1
6
H), 6.86–6.84 (m, 1H), 6.72 (d, J = 9.0 Hz, 1H), 4.82 (s, 1H),
.34–2.30 (m, 1H), 2.13 (d, J = 13.2 Hz, 1H), 1.89–1.80 (m, 2H),
.75 (d, J = 12.0 Hz, 1H), 1.68–1.57 (m, 2H), 1.30–1.24 (m, 3H),
4.2.36. 2',4',5'-triphenyl-2',4'-dihydro-3H-
spiro[benzofuran-2,3'-pyrazol]-3-one (6a)
o
1
Yellow solid; 45 mg, 90% yield; mp 172–174 C; H NMR
13
.14–1.08 (m, 1H). C NMR (150 MHz, CDCl ) δ 197.3, 172.0,
(400 MHz, CDCl ) δ 7.68 (d, J = 7.6 Hz, 1H), 7.55–7.53z (m,
3
3
57.7, 142.4, 141.1, 130.5, 130.2, 130.1, 129.0, 128.9, 128.6,
28.6, 128.0, 125.5, 123.2, 121.7, 116.1, 113.2, 113.0, 103.7,
2H), 7.44–7.40 (m, 1H), 7.27–7.21 (m, 3H), 7.17–7.07 (m, 7H),
7.04–6.99 (m, 3H), 6.94–6.90 (m, 1H), 6.55 (d, J = 8.4 Hz, 1H),
13
5.1, 37.4, 31.3, 29.3, 26.0, 26.0, 25.7; HRMS(ESI) calcd. for
5.16 (s, 1H). C NMR (100 MHz, CDCl ) δ 198.1, 169.1, 149.5,
3
+
C H N O [M + H] 473.22235; found: 473.22229.
141.7, 139.4, 130.9, 130.9, 130.2, 129.1, 128.9, 128.3, 128.0,
32
29
2
2
1
6
27.1, 124.2, 122.3, 122.2, 120.6, 116.0, 114.5, 112.9, 102.5,
4
.2.32. 2',4'-diphenyl-5'-styryl-2',4'-dihydro-3H-
+
3.9; HRMS(ESI) calcd. for C H N O [M + H] 417.15975;
28
21
2
2
spiro[naphtho[2,3-b] furan-2,3'-pyrazol] -3-one
found: 417.15978.
(
3af)
o
1
Yellow solid; 42 mg, 71% yield; mp 176–178 C; H NMR
4.2.37. 5-methoxy-2',4',5'-triphenyl-2',4'-dihydro-
(
400 MHz, CDCl ) δ 8.80 (d, J = 8.0 Hz, 1H), 7.91 (d, J = 8.8
3H-spiro[benzofuran-2,3'-pyrazol]-3-one (6b)
3
o
1
Hz, 1H), 7.77 (d, J = 8.0 Hz, 1H), 7.72 (t, J = 8.0 Hz, 1H), 7.50
Yellow solid; 47 mg, 88% yield; mp 131–133 C; H NMR
(t, J = 7.6 Hz, 1H), 7.26–7.22 (m, 5H), 7.14–7.08 (m, 10H), 6.90
(
400 MHz, CDCl ) δ 7.54 (s, 2H), 7.26–7.03 (m, 14H), 6.95–6.90
3
1
3
(t, J = 7.2 Hz, 1H), 6.71 (d, J = 9.2 Hz, 1H), 6.30 (d, J = 16.8 Hz,
(m, 1H), 6.50–6.47 (m, 1H), 5.16 (s, 1H), 3.80 (s, 3H). C NMR
13
1
1
1
1
H), 5.05 (s, 1H). C NMR (150 MHz, CDCl ) δ 196.6, 172.1,
3
(150 MHz, CDCl ) δ 198.4, 164.5, 155.0, 149.5, 141.7, 131.0,
3
50.3, 141.6, 141.4, 136.3, 135.3, 130.8, 130.3, 130.2, 129.2,
29.1, 128.7, 128.6, 128.6, 128.4, 128.1, 128.1, 126.7, 125.7,
1
31.0, 130.2, 129.3, 129.1, 128.9, 128.3, 128.0, 127.1, 122.1,
120.5, 116.0, 114.0, 110.0, 103.9, 103.0, 64.0, 55.8; HRMS(ESI)
+
23.3, 122.4, 119.4, 116.2, 113.2, 113.1, 103.1, 63.5;
calcd. for C H N O [M + H] 447.17032; found: 447.16990.
29
23
2
3
+
HRMS(ESI) calcd. for C H N O [M + H] 493.19105; found:
4
34
25
2
2
4
.2.38. 2',4',5'-triphenyl-2',4'-dihydro-2H-
93.19032.
spiro[benzofuran-3,3'-pyrazol]-2-one (7a)
o
1
4
.2.33. 2'-(4-fluorophenyl)-4',5'-diphenyl-2',4'-
Yellow solid; 36 mg, 73% yield; mp 172–174 C; H NMR
dihydro-3H-spiro[naphtho[2,3-b]furan-2,3'-
pyrazol] -3-one (3ag)
(
400 MHz, CDCl ) δ 7.68–7.66 (m, 2H), 7.30–7.28 (m, 3H),
3
7
.26–7.19 (m, 4H), 7.14–7.10 (m, 2H), 7.07–7.02 (m, 3H), 6.91
o
1
Yellow solid; 48 mg, 83% yield; mp 176–178 C; H NMR
(
d, J = 8.0 Hz, 3H), 6.77–6.73 (m, 1H), 6.34–6.32 (m, 1H), 5.13
13
(600 MHz, CDCl ) δ 8.81 (d, J = 8.4 Hz, 1H), 7.94 (d, J = 9.0
3
(s, 1H). C NMR (150 MHz, CDCl ) δ 174.5, 153.0, 149.6,
3
Hz, 1H), 7.79 (d, J = 8.4 Hz, 1H), 7.73 (t, J = 8.4 Hz, 1H), 7.55–
.50 (m, 3H), 7.29–7.26 (m, 3H), 7.15–7.14 (m, 4H), 7.04–7.01
m, 2H), 6.92–6.89 (m, 1H), 6.77 (t, J = 8.4 Hz, 2H), 6.72 (d, J =
1
1
44.0, 133.5, 131.1, 130.6, 129.2, 129.1, 129.0, 128.9, 128.5,
7
(
28.4, 126.8, 126.5, 124.1, 123.9, 122.4, 116.8, 111.1, 76.0, 63.2;
+
HRMS(ESI) calcd. for C H N O [M + H] 417.15975; found:
417.15973.
28
21
2
2
13
9
1
.0 Hz, 1H), 5.25 (s, 1H). C NMR (150 MHz, CDCl ) δ 196.7,
72.2, 158.7 (d, J = 240.0 Hz), 150.0, 141.5, 138.1 (d, J = 3.0
3
4
'-cyclohexyl-2',5'-diphenyl-2',4'-dihydro-2H-
Hz), 130.9, 130.3, 130.2, 129.2, 129.0, 128.7, 128.5, 128.3,
28.1, 128.0, 127.1, 125.8, 123.3, 118.5, 118.4, 115.7 (d, J = 22.5
spiro[benzofuran-3,3'-pyrazol]-2-one (7b)
1
o
1
Hz), 113.1, 113.0, 103.7, 63.9; HRMS(ESI) calcd. for
Yellow solid; 37 mg, 73% yield; mp 181–183 C; H NMR
+
C H FN O [M + H] 485.16598; found: 485.16606.
32
22
2
2
(400 MHz, CDCl ) δ 7.75–7.73 (m, 2H), 7.54–7.48 (m, 2H),
3
7
.45–7.41 (m, 3H), 7.30 (t, J = 7.6 Hz, 1H), 7.20 (d, J = 8.0 Hz,

9
(
c) Q. Luo, X.-Y. Wei, J. Yang, J.-F. Luo, R. Liang, Z.-C. Tu,
1
1
1
1
1
2
4
H), 7.11–7.07 (m, 2H), 6.91–6.84 (m, 3H), 3.83 (d, J = 2.0 Hz,
Y.-X. Cheng, J. Nat. Prod. 80 (2017) 61;
H), 2.12–2.05 (m, 1H), 1.76–1.68 (m, 2H), 1.57–1.52 (m, 3H),
13
(d) Q.-M. Li, J.-G. Luo, Y.-M. Zhang, Z.-R. Li, X.-B. Wang, M.-
H. Yang, J. Luo, H.-B. Sun, Y.-J. Chen, L.-Y. Kong, Chem.-Eur. J.
.29–0.88 (m, 5H). C NMR (150 MHz, CDCl ) δ 174.5, 153.7,
3
52.6, 144.6, 133.2, 131.1, 129.3, 128.9, 128.4, 127.5, 127.0,
24.7, 124.1, 122.5, 117.4, 112.0, 76.8, 61.5, 39.2, 33.8, 29.1,
2
1 (2015) 13206;
(e) S.-i. Wada, T. Hitomi, H. Tokuda, R. Tanaka, Chem Biodivers
7 (2010) 2303.
+
7.0, 25.8, 25.7; HRMS(ESI) calcd. for C H N O [M + H]
28
27
2
2
[
7] (a) P.P. Kaishap, G. Duarah, B. Sarma, D. Chetia, S. Gogoi,
Angew. Chem., Int. Ed. 57 (2018) 456;
23.20670; found: 423.20682.
(
b) B. Li, F. Gao, X. Feng, M. Sun, Y. Guo, D. Wen, Y. Deng, J.
Huang, K. Wang, W. Yan, Org. Chem. Front. 6 (2019) 1567;
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Zhao, Angew. Chem., Int. Ed. 57 (2018) 7860;
Acknowledgments
(
We are thankful for the financial support from the National
Natural Science Foundation of China (Grant No. 21502154,
(
2
1961034, and 21362033) and the Science and Technology
Program of Gansu Province (No. 17JR5RA073 and
8JR3RA091).
(
(
e) Z.-P. Wang, S. Xiang, P.-L. Shao, Y. He, J. Org. Chem. 83
2018) 10995;
1
(f) T. Du, Z. Li, C. Zheng, G. Fang, L. Yu, J. Liu, G. Zhao,
Tetrahedron 74 (2018) 7485;
(
(
(
(
(
(
g) H. Ni, Z. Yu, W. Yao, Y. Lan, N. Ullah, Y. Lu, Chem. Sci. 8
2017) 5699;
h) D. Kowalczyk, J. Wojciechowski, Ł. Albrecht, Synthesis 49
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A regioselective [3+2] cycloaddition reaction of benzoaurones with nitrile imines was
developed. Resorting to this efficient strategy, a series of compelling spiro
[
naphthofuran-2,3'-pyrazoline]-3-ones were efficiently obtained in good to excellent
yields (65% to 94% yield) with high regioselectivity.