Generation of 3-(1H-isochromen-1-yl)-1H-indole via silver triflate-catalyzed tandem reaction of 2-alkynylbenzaldehyde with indole

Article abstract of DOI:10.3987/COM-10-S(E)68

A facile and efficient method is developed for synthesis of 3-(1H-isochromen-1-yl)-1H-indole via silver triflate-catalyzed tandem reaction of 2-alkynylbenzaldehyde with indole. The reaction proceeds smoothly in DMF at room temperature with good substrate generality. The availability of the starting materials combined with mild reaction conditions and the high efficiency of this synthetic route would be attractive and beneficial for the focused library construction. The Japan Institute of Heterocyclic Chemistry.

Full text of DOI:10.3987/COM-10-S(E)68

HETEROCYCLES, Vol. 82, No. 2, 2011
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HETEROCYCLES, Vol. 82, No. 2, 2011, pp. 1239 - 1249. © The Japan Institute of Heterocyclic Chemistry
Received, 24th June, 2010, Accepted, 4th August, 2010, Published online, 6th August, 2010
DOI: 10.3987/COM-10-S(E)68
GENERATION OF 3-(1H-ISOCHROMEN-1-YL)-1H-INDOLE VIA
SILVER TRIFLATE-CATALYZED TANDEM REACTION OF
2-ALKYNYLBENZALDEHYDE WITH INDOLE
Banlai Ouyang,a Jianjun Yuan,a Qin Yang,a Qiuping Ding,a Yiyuan Peng,*,a
and Jie Wu*,b
aKey Laboratory of Green Chemistry of Jiangxi Province, College of Chemistry
and Chemical Engineering, Jiangxi Normal University, Nanchang 330027, China
bDepartment of Chemistry, Fudan University, 220 Handan Road, Shanghai
200433, China. E-mail: jie_wu@fudan.edu.cn
This paper is dedicated to Prof. Dr. Albert Eschenmoser on the occasion of his
85th birthday.
Abstract – A facile and efficient method is developed for synthesis of
3-(1H-isochromen-1-yl)-1H-indole via silver triflate-catalyzed tandem reaction of
2-alkynylbenzaldehyde with indole. The reaction proceeds smoothly in DMF at
room temperature with good substrate generality. The availability of the starting
materials combined with mild reaction conditions and the high efficiency of this
synthetic route would be attractive and beneficial for the focused library
construction.
INTRODUCTION
It is well known that natural product-like compounds can be utilized to dissect the circuitry of cells,
which is analogous to the use of mutations in genetics.1 For access such small molecules capable of
modulating any pathway or process of interest, diversity-oriented synthesis is an efficient device.2 Among
the methods employed, tandem reactions from easily available starting materials provide an efficient and
powerful tool to produce a collection of structurally diverse compounds.3,4 As we know, the
1H-isochromene core is regarded as a privileged scaffold which can be found in many natural products
and drug candidates with remarkable biological activities.5 Thus, continuous efforts have been observed
for the development of new methods for its construction.6 On the other hand, the indole skeleton is an

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HETEROCYCLES, Vol. 82, No. 2, 2011
important substructure as well in both natural products and therapeutic agents.7 As part of an ongoing
program in our laboratory for accessing natural product-like compounds used in different biological
assays,8,9 we conceived that the 1H-isochromene with an indole substituent might be a good candidate for
library development. Therefore, we started to consider the possibility for the synthesis of this kind of
compound.
Recently, 2-alkynylbenzaldehyde was discovered as a versatile building block for carbocycles and
heterocycles formation.10,11 Its reliability and the ready availability of the starting materials made it
attractive for reaction development. For instance, Yamamoto and Asao described the naphthyl ketones
synthesis via AuCl3-catalyzed [4+2] benzannulation of 2-alkynylbenzaldehydes with alkynes.11a,b Very
recently, Li and co-workers reported a PdCl2-catalyzed domino reaction of 2-alkynylbenzaldehyde with
indole for generation of fluorescent 5H-benzo[b]carbazol-6-yl ketones.10i We also found that
1H-isochromen-1-ylphosphonates could be easily accessible via AgOTf-catalyzed reaction of
2-alkynylbenzaldehyde with diethyl phosphite. During the reaction process, it was recognized that the
metal-catalyzed cyclization would occur firstly to generate an isobenzopyrylium complex, which then
triggered intermolecular attack of the nucleophile thus affording 1H-isochromene derivatives. Encouraged
by these results, we reasoned that 3-(1H-isochromen-1-yl)-1H-indoles could be synthesized via
metal-catalyzed tandem reactions of 2-alkynylbenzaldehydes with indoles under suitable conditions.
Herein, we would like to disclose our recent efforts for this transformation.
RESULTS AND DISCUSSION
2-Alkynylbenzaldehyde
1
was conveniently prepared from the commercially available
2-bromobenzaldehyde with alkyne via Sonogashira coupling reaction according to the literature method.12
The preliminary experiments were carried out for the reaction of 2-alkynylbenzaldehyde 1a with indole
2a catalyzed by different Lewis acids in various solvents at room temperature (Table 1). To our delight,
the desired product 3a was afforded in 40% yield when the reaction was performed in MeCN in the
presence of AgOTf (5 mol%) as a catalyst (Table 1, entry 1). Only a trace amount of product was detected
when the catalyst was replaced by CuOTf, Cu(OTf)2, La(OTf)3, Sc(OTf)3, or Bi(OTf)3 (Table 1, entries
2-6). The product from double addition of indole to aldehyde was obtained when Dy(OTf)3, Yb(OTf)3, or
Zn(OTf)2 was employed as the catalyst in the above reaction (Table 1, entries 7-9). The yield was
increased to 56% when 10 mol% of AgOTf was used (Table 1, entry 10). Further screening of solvents
demonstrated that the reaction worked the most efficiently in DMF, which furnished the corresponding
product 3a in 66% yield (Table 1, entry 18). Inferior yields were generated when other solvents were
utilized in the reaction.

HETEROCYCLES, Vol. 82, No. 2, 2011
1241
Table 1. Initial studies for reaction of 2-alkynylbenzaldehyde 1a with indole 2a
HN
CHO
Lewis acid
(cat.)
+
N
solvent, rt
O
H
Ph
1a
3a
2a
Ph
Entry
1
Lewis acid
solvent
Yield (%)a
40
AgOTf (5 mol%)
CuOTf (5 mol%)
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
THF
2
trace
trace
trace
trace
trace
61b
3
Cu(OTf)2 (5 mol%)
La(OTf)3 (5 mol%)
Sc(OTf)3 (5 mol%)
Bi(OTf)3 (5 mol%)
Yb(OTf)3 (5 mol%)
Zn(OTf)2 (5 mol%)
Dy(OTf)3 (5 mol%)
AgOTf (10 mol%)
AgOTf (10 mol%)
AgOTf (10 mol%)
AgOTf (10 mol%)
AgOTf (10 mol%)
AgOTf (10 mol%)
AgOTf (10 mol%)
AgOTf (10 mol%)
AgOTf (10 mol%)
AgOTf (10 mol%)
AgOTf (10 mol%)
AgOTf (10 mol%)
4
5
6
7
8
52b
63b
9
10
11
12
13
14
15
16
17
18
19
20
21
56
trace
trace
trace
trace
trace
33
CH2Cl2
acetone
EtOH
MeOH
DMSO
NMP
trace
66
DMF
DMAc
toluene
ClCH2CH2Cl
50
trace
trace
a Isolated yield based on 2-alkynylbenzaldehyde 1a.
b Product from double addition of indole to aldehyde was obtained.
Next, the scope of the tandem reaction of 2-alkynylbenzaldehyde 1 with indole 2 was examined and the
results were presented in Table 2. From Table 2, we found that all reactions proceeded smoothly leading

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to the desired 3-(1H-isochromen-1-yl)-1H-indole 3 in good to excellent yields. For example, reaction of
2-alkynylbenzaldehyde 1a with 2-methylindole 2b gave rise to the 1H-isochromene 3b in 70% yield
(Table 2, entry 2). A slightly lower yield was obtained when 5-methyl or 5-bromoindole was used as a
replacement (Table 2, entries 3 and 4). Substrate 1b or 1c also worked well to generate the corresponding
product in good yield (Table 2, entries 5-8). Under the standard conditions, the methyl-, fluoro-, or
[1,3]dioxolyl-substituted 2-alkynylbenzaldehyde 1d-1f were tested as well in the reactions of various
indoles (Table 2, entries 9-14). As expected, all reactions gave rise to the desired products in good yields.
In addition, we did not observe the influence of the electron effect on the aromatic backbone of the
substrates.
Table 2. Synthesis of 3-(1H-isochromen-1-yl)-1H-indole 3 via silver triflate-catalyzed tandem reaction of
2-alkynylbenzaldehyde 1 with indole 2
HN
CHO
R3
R1
AgOTf (10 mol %)
R3
+
N
DMF, rt
O
H
R1
R2
1
R2
2
3
Entry
1
Substrate 1
Indole 2
Product 3
Yield (%)a
66
CHO
3a
N
H
2a
Ph
1a
2
3
4
1a
3b
3c
3d
70
62
55
N
H
2b
1a
1a
N
H
2c
Br
N
H
2d
CHO
5
3e
67
N
H
2a
C6H4p-Me
1b

HETEROCYCLES, Vol. 82, No. 2, 2011
1243
6
7
1b
3f
75
60
N
H
2c
CHO
3g
N
H
2a
C6H4p-Cl
1c
8
9
1c
3h
3i
95
78
N
H
2c
CHO
N
H
2a
Ph
1d
10
11
12
1d
1d
1d
3j
3k
3l
62
62
91
N
H
2b
2c
N
H
Br
N
H
2d
F
CHO
13
14
3m
3n
63
80
N
H
2c
Ph
1e
CHO
O
N
O
H
2a
Ph
1f
a Isolated yield based on 2-alkynylbenzaldehyde 1.
CONCLUSION
In summary, we have described an efficient AgOTf-catalyzed tandem reaction of 2-alkynylbenzaldehyde
with indole, which generates the diverse 3-(1H-isochromen-1-yl)-1H-indoles in good yields. This
transformation proceeds through cascade intramolecular cyclization and intermolecular nucleophilic
addition. The easily availability of the starting materials combined with mild reaction conditions, good

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HETEROCYCLES, Vol. 82, No. 2, 2011
substrate generality, and the high efficiency of this synthetic route would be attractive and beneficial for
the focused library construction.
EXPERIMENTAL
General experimental procedure for the synthesis of 3-(1H-isochromen-1-yl)-1H-indole 3 via silver
triflate-catalyzed tandem reaction of 2-alkynylbenzaldehyde 1 with indole 2: Silver triflate (10 mol%)
was added to a solution of 2-alkynylbenzaldehyde 1 (0.25 mmol) and indole 2 (0.3 mmol) in DMF. The
mixture was stirred at room temperature. After completion of reaction as indicated by TLC, the mixture
was diluted with water (10 mL), extracted with EtOAc (10 × 2 mL). The combined organic layers were
then washed with brine, dried over anhydrous Na2SO4, and concentrated under reduced pressure. The
residue was purified by flash column chromatography (n-hexane/ethyl acetate) to afford the desired
product 3.
1
3-(3-Phenyl-1H-isochromen-1-yl)-1H-indole (3a): White solid, mp 153-154 C; H NMR (400 MHz,
CDCl3) δ 8.00 (s, 1H), 7.86 (d, J = 8.0 Hz, 1H), 7.64-7.66 (m, 2H), 7.35 (d, J = 8.0 Hz, 1H), 7.30-7.10 (m,
13
8H), 6.97 (d, J = 7.2 Hz, 1H), 6.85 (d, J = 2.4 Hz, 1H), 6.68 (s, 1H), 6.49 (s, 1H); C NMR (100 MHz,
CDCl3) δ 152.6, 136.6, 134.8, 132.0, 130.3, 128.6, 128.2, 128.1, 126.5, 126.4, 125.4, 125.1, 124.9, 123.6,
122.4, 120.1, 120.0, 115.3, 111.3, 100.8, 74.0; IR (KBr): ν (cm-1) 3415, 3022, 1622, 1491, 1455. HRMS
calcd for C23H18NO (M+H): 324.1388, found: 324.1386.
2-Methyl-3-(3-phenyl-1H-isochromen-1-yl)-1H-indole (3b): Yellow solid, mp 63-65 C; 1H NMR (400
MHz, CDCl3) δ 8.00 (s, 1H), 7.72 (d, J = 7.6 Hz, 2H), 7.44 (d, J = 4.0 Hz, 1H), 7.34-7.23 (m, 5H),
7.18-7.11 (m, 2H), 7.05-6.98 (m, 2H), 6.74 (d, J = 7.6 Hz, 1H), 6.57 (s, 1H), 6.50 (s, 1H), 2.41 (s, 3H);
13C NMR (100 MHz, CDCl3) δ 154.3, 135.4, 134.5, 132.8, 130.8, 128.7, 128.2, 128.0, 127.8, 126.5, 125.2,
125.0, 123.4, 121.3, 120.1,119.7, 110.2, 109.5, 101.0, 74.5, 12.3; IR (KBr): ν (cm-1) 3400, 3057, 2918,
2849, 1621, 1492, 1460. HRMS calcd for C24H20NO (M+H): 338.1545, found: 338.1539.
1
5-Methyl-3-(3-phenyl-1H-isochromen-1-yl)-1H-indole (3c): White solid, mp 179-180 C; H NMR
(400 MHz, CDCl3) δ 7.93 (s, 1H), 7.67-7.63 (m, 3H), 7.29-7.09 (m, 7H), 7.03 (d, J = 8.4 Hz, 1H), 6.95 (d,
13
J = 7.2 Hz, 1H), 6.82 (d, J = 2.4 Hz, 1H), 6.63 (s, 1H), 6.49 (s, 1H), 2.44 (s, 3H); C NMR (100 MHz,
CDCl3) δ 152.8, 134.9, 134.8, 132.1, 130.5, 129.3, 128.6, 128.2, 128.1, 126.7, 126.4, 125.5, 125.1, 125.0,
124.1, 123.6, 119.8, 114.7, 110.9, 100.9, 74.2, 21.6; IR (KBr): ν (cm-1) 3412, 3057, 2922, 2858, 1625,
1488, 1453. HRMS calcd for C24H20NO (M+H): 338.1545, found: 338.1541.
1
5-Bromo-3-(3-phenyl-1H-isochromen-1-yl)-1H-indole (3d): Green solid, mp 67-68 C; H NMR (400
MHz, CDCl3) δ 8.08 (s, 1H), 7.96 (s, 1H), 7.63 (d, J = 7.2 Hz, 2H), 7.29-7.22 (m, 5H), 7.17 (d, J = 7.6 Hz,
1H), 7.13-7.10 (m, 2H), 6.91 (d, J = 7.2 Hz, 1H), 6.75 (d, J = 2.0 Hz, 1H), 6.57 (s, 1H), 6.48 (s, 1H); 13C
NMR (100 MHz, CDCl3) δ 152.5, 135.2, 134.6, 131.9, 130.0, 128.8, 128.3, 128.2, 128.1, 126.6, 126.1,

HETEROCYCLES, Vol. 82, No. 2, 2011
1245
125.4, 125.3, 125.0, 123.8, 122.7, 115.0, 113.4, 112.9, 101.0, 73.8; IR (KBr): ν (cm-1) 3420, 3062, 1626,
1601, 1492, 1454. HRMS calcd for C23H17BrNO (M+H): 402.0494, found: 402.0499.
1
3-(3-p-Tolyl-1H-isochromen-1-yl)-1H-indole (3e): Yellow solid, mp 144-145 C; H NMR (400 MHz,
CDCl3) δ 8.01 (s, 1H), 7.85 (d, J = 8.0 Hz, 1H), 7.54 (d, J = 8.0 Hz, 2H), 7.33 (d, J = 8.0 Hz, 1H),
7.28-7.07 (m, 7H), 6.96 (d, J = 7.6 Hz, 1H), 6.84 (d, J = 2.0 Hz, 1H), 6.66 (s, 1H), 6.44 (s, 1H), 2.29 (s,
3H); 13C NMR (100 MHz, CDCl3) δ 152.8, 138.6, 136.6, 132.2, 132.0, 130.3, 128.9, 128.1, 126.5, 126.2,
125.4, 125.1, 124.8, 123.5, 122.4, 120.2, 120.0, 115.4, 111.3, 100.1, 74.0, 21.3; IR (KBr): ν (cm-1) 3416,
3064, 3014, 2922, 1621, 1509, 1456. HRMS calcd for C24H20NO (M+H): 338.1545, found: 338.1557.
1
5-Methyl-3-(3-p-tolyl-1H-isochromen-1-yl)-1H-indole (3f): Brown solid, mp 148-149 C; H NMR
(400 MHz, CDCl3) δ 7.86 (s, 1H), 7.61 (s, 1H), 7.55 (d, J = 8.0 Hz, 2H), 7.25-6.91 (m, 8H), 6.78 (d, J =
13
2.4 Hz, 1H), 6.59 (s, 1H), 6.44 (s, 1H), 2.43 (s, 3H), 2.29 (s, 3H); C NMR (100 MHz, CDCl3) δ 153.0,
138.7, 134.9,132.3, 132.0, 130.5, 129.3, 129.0, 128.1, 126.8, 126.2, 125.5, 125.1, 125.0, 124.0, 123.5,
119.8, 114.7, 111.0, 100.2, 74.2, 21.6, 21.3; IR (KBr): ν (cm-1) 3422, 3030, 2919, 2857, 1623, 1511, 1487.
HRMS calcd for C25H22NO (M+H): 352.1701, found: 352.1709.
1
3-(3-(4-Chlorophenyl)-1H-isochromen-1-yl)-1H-indole (3g): White solid, mp 150-151 C; H NMR
(400 MHz, CDCl3) δ 8.02 (s, 1H), 7.83 (d, J = 7.2 Hz, 1H), 7.56 (d, J = 7.8 Hz, 2H), 7.34-7.11 (m, 8H),
6.96 (d, J = 7.6 Hz, 1H), 6.81 (d, J = 2.4 Hz, 1H), 6.67 (s, 1H), 6.45 (s, 1H); 13C NMR (100 MHz, CDCl3)
δ 151.5, 136.6, 134.3, 133.3, 131.7, 130.3, 128.4, 128.2, 126.6, 126.4, 125.2, 124.9, 123.8, 122.5, 120.1,
120.0, 115.3, 111.4, 101.2, 74.1; IR (KBr): ν (cm-1) 3391, 3066, 1623, 1490, 1455. HRMS calcd for
C23H17ClNO (M+H): 358.0999, found: 358.0410.
3-(3-(4-Chlorophenyl)-1H-isochromen-1-yl)-5-methyl-1H-indole (3h): Yellow solid, mp 197-198 C;
1H NMR (400 MHz, CDCl3) δ 7.97 (br, 1H), 7.62-7.57 (m, 2H), 7.28-7.11 (m, 6H), 7.05 (d, J = 8.4 Hz,
1H), 6.96 (d, J = 7.6 Hz, 1H), 6.83 (d, J = 2.4 Hz, 1H), 6.63 (s, 1H), 6.47 (s, 1H), 2.45 (s, 3H); 13C NMR
(100 MHz, CDCl3) δ 151.6, 134.9, 134.3, 133.3, 131.8, 130.4, 129.4, 128.4, 128.1, 126.7, 126.6, 125.2,
125.0, 124.1, 123.7, 119.7, 114.6, 111.0, 101.2, 74.2, 21.6; IR (KBr): ν (cm-1) 3415, 3072, 2919, 1626,
1490, 1405. HRMS calcd for C24H19ClNO (M+H): 372.1155, found: 372.1163.
1
3-(6-Methyl-3-phenyl-1H-isochromen-1-yl)-1H-indole (3i): Yellow solid, mp 152-153 C; H NMR
(400 MHz, CDCl3) δ 7.93 (s, 1H), 7.83 (d, J = 7.6 Hz, 1H), 7.62 (d, J = 6.8 Hz, 2H), 7.26-7.11 (m, 5H),
6.98 (s, 1H), 6.91 (d, J = 7.6 Hz, 1H), 6.82 (d, J = 7.6 Hz, 1H), 6.77 (d, J = 2.4 Hz, 1H), 6.62 (s, 1H), 6.43
13
(s, 1H), 2.34 (s, 3H); C NMR (100 MHz, CDCl3) δ 152.6, 137.7, 136.6, 134.9, 132.0, 128.6, 127.7,
127.2, 126.5, 125.4, 125.1, 125.0, 124.4, 122.4, 120.2, 120.0, 115.4, 111.4, 100.9, 74.0, 21.4; IR (KBr):
ν (cm-1) 3415, 3059, 2916, 1621, 1492, 1455. HRMS calcd for C24H20NO (M+H): 338.1545, found:
338.1551.

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HETEROCYCLES, Vol. 82, No. 2, 2011
1
2-Methyl-3-(6-methyl-3-phenyl-1H-isochromen-1-yl)-1H-indole (3j) Yellow solid, mp 69-70 C; H
NMR (400 MHz, CDCl3) δ 7.92 (s, 1H), 7.71-7.69 (m, 2H), 7.44 (d, J = 7.6 Hz, 1H), 7.29-7.25 (m, 4H),
7.10 (t, J = 8.0 Hz, 1H), 7.00-7.01 (m, 2H), 6.82 (d, J = 7.6 Hz, 1H), 6.60 (d, J = 8.0 Hz, 1H), 6.52 (s, 1H),
6.46 (s, 1H), 2.33 (s, 3H), 2.32 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 154.3, 137.7, 135.4, 134.7, 134.6,
132.8, 128.7, 128.3, 128.2, 127.9, 127.2, 125.3, 125.0, 124.2, 121.3,120.2, 119.7, 110.4, 109.6, 101.1,
74.6, 21.3, 12.3; IR (KBr): ν (cm-1) 3403, 3058, 2920, 2851, 1622, 1460, 1046. HRMS calcd for
C25H22NO (M+H): 352.1701, found: 352.1712.
5-Methyl-3-(6-methyl-3-phenyl-1H-isochromen-1-yl)-1H-indole (3k) Yellow solid, mp 172-173 C;
1H NMR (400 MHz, CDCl3) δ 7.93 (s, 1H), 7. 65-7.62 (m, 3H), 7.26-7.18 (m, 4H), 7.02-6.99 (m, 2H),
13
6.91 (d, J = 8.0 Hz, 1H), 6.84-6.80 (m, 2H), 6.59 (s, 1H), 6.44 (s, 1H), 2.43 (s, 3H), 2.35 (s, 3H); C
NMR (100 MHz, CDCl3) δ 152.8, 137.6, 134.9, 132.0, 129.2, 128.6, 128.2, 127.8, 127.1, 126.8, 125.5,
125.0, 124.3, 124.0, 119.8, 114.8, 111.0, 100.9, 74.1, 21.6, 21.3; IR (KBr): ν (cm-1) 3419, 2922, 2851,
1624, 1493, 1450. HRMS calcd for C25H22NO (M+H): 352.1701, found: 352.1709.
1
5-Bromo-3-(6-methyl-3-phenyl-1H-isochromen-1-yl)-1H-indole (3l) Green solid, mp 64-65 C; H
NMR (400 MHz, CDCl3) δ 8.04 (br, 1H), 7.95 (s, 1H), 7.62 (d, J = 7.2 Hz, 2H), 7.28-7.21 (m, 4H), 7.08
(d, J = 8.4 Hz, 1H), 6.98 (s, 1H), 6.92 (d, J = 7.6 Hz, 1H), 6.78 (d, J = 7.6 Hz, 1H), 6.75 (s, 1H), 6.53 (s,
13
1H), 6.43 (s, 1H), 2.34 (s, 3H); C NMR (100 MHz, CDCl3) δ 152.5, 137.9, 135.3, 134.7, 131.8, 128.7,
128.3, 128.1, 127.3, 126.1, 125.4, 125.3, 124.9, 124.8, 124.5, 122.7, 115.1, 113.3, 112.9, 101.1, 73.8,
21.4; IR (KBr): ν (cm-1) 3421, 2919, 1626, 1492, 1449. HRMS calcd for C24H19BrNO (M+H): 416.0650,
found: 416.0656.
3-(7-Fluoro-3-phenyl-1H-isochromen-1-yl)-5-methyl-1H-indole (3m) Yellow solid, mp 198-199 C;
1H NMR (400 MHz, CDCl3) δ 7.97 (s, 1H), 7.66-7.64 (m, 2H), 7.58 (s, 1H), 7.29-7.23 (m, 4H), 7.14-7.11
(m, 1H), 7.05 (d, J = 8.4 Hz, 1H), 6.99-6.94 (m, 1H), 6.89 (d, J = 1.6 Hz, 1H), 6.66 (d, J = 7.2 Hz, 1H),
6.56 (s, 1H), 6.48 (s, 1H), 2.44 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 152.3, 134.9, 134.6, 132.7, 129.5,
2
128.7, 128.4, 128.3, 128.2, 126.5, 125.3, 125.0, 124.9, 124.2, 119.7, 114.8 (d, JCF = 22.0 Hz), 113.9,
112.5 (d, 2JCF = 23.0 Hz), 111.0, 100.1, 74.0, 21.6; IR (KBr): ν (cm-1) 3412, 3065, 2929, 2855, 1609, 1494.
HRMS calcd for C24H19FNO (M+H): 356.1451, found: 356.1455.
1
3-(7-Phenyl-5H-[1,3]dioxolo[4,5-g]isochromen-5-yl)-1H-indole (3n) Blue solid, mp 194-195 C; H
NMR (400 MHz, CDCl3) δ 7.99 (s, 1H), 7.83 (d, J = 8.0 Hz, 1H), 7.61 (d, J = 7.2 Hz, 2H), 7.32 (d, J =
8.0 Hz, 1H), 7.26-7.12 (m, 4H), 6.89 (s, 1H), 6.68 (s, 1H), 6.55 (s, 1H) , 6.46 (s, 1H) , 6.38 (s, 1H) , 5.89
(s, 2H); 13C NMR (100 MHz, CDCl3) δ 151.3, 147.4, 146.1, 136.7, 134.7, 128.4, 128.2, 126.5, 126.4,
125.2, 124.8, 124.1, 122.4, 120.2, 120.1, 115.3, 111.3, 106.3, 104.5, 101.0, 100.9, 74.1; IR (KBr): ν
(cm-1) 3384, 3069, 2900, 1640, 1499, 1482. HRMS calcd for C24H18NO3 (M+H): 368.1287, found:

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368.1298.
ACKNOWLEDGEMENTS
Financial support from the National Natural Science Foundation of China (Nos. 20862009 and 20962010)
and the Natural Science Foundation of Jiangxi Province (No. 2008GQH0026) is gratefully acknowledged.
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