A synthesis of 3-substituted 3-hydroxyoxindoles via an indium-mediated Barbier-type allylation of isatins in PEG-400

Article abstract of DOI:10.3184/174751911X13090135895019

A simple procedure for the synthesis of 3-allyl-3-hydroxyoxindoles from isatins in PEG-400 using organoindium reagents generated in situ is described. A variety of isatins reactede with allyl bromides to give the target products with excellent yields in mild conditions.

Full text of DOI:10.3184/174751911X13090135895019

390 RESEARCH PAPER
JULY, 390–393
JOURNAL OF CHEMICAL RESEARCH 2011
A synthesis of 3-substituted 3-hydroxyoxindoles via an indium-mediated
Barbier-type allylation of isatins in PEG-400
Junmin Chena*, Tangjun Yuana and Li Liub
aDepartment of Chemistry, Jiangxi Normal University, Nanchang, 330022, P. R. China
bJiangxi College ofTraditional Chinese Medicine, Fuzhou, 344000, P. R. China
A simple procedure for the synthesis of 3-allyl-3-hydroxyoxindoles from isatins in PEG-400 using organoindium
reagents generated in situ is described. A variety of isatins reactede with allyl bromides to give the target products
with excellent yields in mild conditions.
Keywords: indium, allylation, PEG-400, 3-substituted 3-hydroxyoxindoles
The 3-substituted-3-hydroxy-2-oxindole scaffold has been
shown to be at the core of several natural products with a wide
spectrum of biological activities, such as convolutamydines,1
donaxaridines2 maremycins,3 dioxibrassinines,4 celogentin K,5
3′-hydroxy glucoisatisin,6 and TMC-95A.7 The development
of practical methods for their preparation is of interest. 3-
Substituted 3-hydroxyoxindoles are also encountered in a large
variety of natural and artificial bioactive compounds and
Scheme 1 Indium-mediated allylation of isatin in PEG-400.
can be used for the total synthesis of natural products such as
CPC-18,9 and flustraminol.10,11 The formation of quaternary
carbon centres by the addition of nucleophiles to ketone
Result and discussion
derivatives still constitutes a major challenge for synthetic
chemistry.
Since 1988, when Araki et al. used indium for the first time
We initially selected isatin and allyl bromide as a model
substrate for optimisation of the reaction conditions. Selected
results from our screening experiments are summarised in
as a mediating metal in Barbier-type additions of allyl bromide
Table 1. In our preliminary studies we found that, with pure
to carbonyl compounds,12 indium attracted considerable
water as the reaction media, the reaction proceeded at room
temperature (r.t.) in 90 min and the corresponding product
3-allyl-3-hydroxyoxindole was obtained with excellent yield
(Table 1, entry 1). The use of aqueous PEG-400 as a mixed
solvent gave slow reaction (Table 1, entry 2). To our delight,
PEG-400 as a reaction medium afforded a 99% yield of the
attention from various groups working on the development of
new synthetic methods. Because of its low toxicity, tolerance
towards air and moisture and low ionisation potential,13,14
indium metal-mediated carbon–carbon bond formation
reactions, including the Barbier-type allylation of carbonyl
compounds, have become
a major topic in organic
desired product at r.t. for 5 min (Table 1, entry 3). Next, using
a standard protocol we screened different metal mediators
(zinc, tin). No products were observed (Table 1, entries 4, 5).
The scope of substrates was then investigated under the
optimised reaction conditions. The results shown in Table 2
reveal that all the isatins were converted rapidly to give the
corresponding 3-allyl-3-hydroxyoxindoles in excellent yields.
We explored 2-methyl allyl bromide and 3-methyl allyl
bromide as Barbier-type allylation reagents, affording the
corresponding products with excellent yields of 97% and
98% respectively (Table 2, entries 2 and 3). Among the sub-
stituted isatins, both electron-donating groups and electron-
withdrawing groups such as methyl, chloro, and bromo had no
demonstrable effect on the yield of products (Table 2, entries
4–17). Those with ortho substituent such as 4-chloro and
4-bromo also gave excellent yields (Table 2, entries 7–9,
15 and 16). Note that for 4-substituted isatins as substrates and
3-methyl allyl bromide as Barbier-type allylation reagents, the
reactions were reversible when the reaction time was extended
synthesis. Consequently, the synthesis of 3-substituted
3-hydroxyoxindoles by an indium-mediated Barbier-type
allylation of isatins is a synthetically useful transformation.
Nair et al. first reported the allylmetalation of isatins in
anhydrous dimethylformamide,15,16 while Gong et al. described
the allylation of isatins in aqueous environment.17 Recently,
Alcaide et al. reported the preparation of 3-substituted
3-hydroxyoxindoles via the metal-mediated allylation,
allenylation and propargylation reactions of isatins in aqueous
media with full regioselectivity.18 However, these reports
of indium-mediated allylation reaction of isatins used
dimethylformamide (DMF)15,16 and an aqueous organic media
(THF/H2O)17 which caused environmental contamination
and health problems. Furthermore, the scope of the reaction
was limited to isatin only and the reaction was carried in the
presence of additives. Thus, there is a need to develop a gener-
ally applicable, mild and environmentally benign practical
methodology. Recently, polyethylene glycol (PEG) has been
found to be an interesting solvent system.19 PEG is environ-
mentally benign and hasapplications, in coupling,20 substitu-
tion,21 oxidation,22 addition,23 and reduction reactions.24 To the
best of our knowledge, the indium-mediated Barbier-type
allylation of isatins in PEG-400 has not been reported. We now
report a simple and convenient method for the preparation of
3-allyl-3-hydroxyoxindoles from isatins and allyl bromide by
using PEG400 as green reaction medium and indium as the
promoting metal reagent (Scheme 1).
Table 1 Optimisation of allylation reaction conditions a
Entry Reaction media (V/V) Metal
Time/min Yield /% b
1
2
3
4
5
H2O
PEG-400/H2O=1:1
PEG-400
In
In
90min
30min
5min
60min
60min
97
98
In
99
PEG-400
Zn
Sn
NR C
NR C
PEG-400
a Reaction conditions: isatin 1 mmol, indium powder 2 mol,
allyl bromide 3 mmol in PEG-400 2 mL, r.t., TLC tracking.
b Isolated yield after flash column chromatography.
C NR, not reaction.
* Correspondent. E-mail: jxnuchenjm@163.com

JOURNAL OF CHEMICAL RESEARCH 2011 391
Table 2 Indium-mediated Barbier-type allylation of isatins
Entrya
Isatin
Allylbromides
Time /min
5
Product
Yield /%b
99
1
3a
3b
3c
2
3
10
10
10
15
15
15
20
20
15
10
15
25
97
98
98
97
98
98
98
95
99
93
99
96
4
3d
5
3e
3f
6
7
3g
8
3h
3i
9
10
11
12
13
3j
3k
3l
3m

392 JOURNAL OF CHEMICAL RESEARCH 2011
Table 2 Continued
Entrya
Isatin
Allylbromides
Time /min
25
Product
Yield /%b
97
14
3n
15
16
17
25
30
20
96
93
96
3o
3p
3q
a Reactions conditions: isatin 1 mmol, indium power 2 mmol, allyl bromide 3 mmol, PEG-400 2 mL, r.t., TLC tracking.
b Isolated yield after flash column chromatography.
(lit.15 150–152 °C). 1H NMR (CDCl3): δ 2.59–2.64 (m, 1H), 2.72–2.76
(Table 2, entries 8 and 16). Interestingly, the reversible reac-
tions were thoroughly expressed, when a drop of saturated
(m, 1 H), 2.80 (s, 1H), 5.12–5.17 (m, 2H), 5.67–5.71 (m, 1H),
6.58–7.49 (m, 3H), 7.49 (s, 1H). 13C NMR (CDCl3): 42.9, 75.9, 110.1,
NH4Cl aqueous solution was added after the isatin has been
120.7, 123.1, 124.6, 129.8, 130.0, 130.2, 140.1, 179.2. IR (film):
consumed (confirmed by TLC). This may be attributable to the
ν (cm−1) 3339, 2959, 1719, 1626, 1568, 1145, 923, 858, 546, 516.
larger steric hindrance of the 4-substituent products. These
Anal. Calcd for C11H11NO2: C, 69.82; H, 5.85; N, 7.40. Found: C,
indicate that indium-mediated allylation of isatins has a wide
70.15; H, 5.86; N, 7.78%.
range of substrates, which can be used for large-scale synthesis
of the corresponding 3-allyl-3-hydroxyoxindoles. These are
important organic synthesis and medicinal intermediates.
3-(1,1-Dimethylallyl)-3-hydroxy-1,3-dihydro-2H-indol-2-one (3b):
Eluent: hexane–EtOAc (80:20); yield: 97%; colourless crystals;
m.p. 181–182 °C (lit.16 182–183 °C). 1H NMR (CDCl3): δ 1.12
(s, 3H), 1.18 (s, 3H), 2.82 (s, 1H), 5.14 (d, J = 17.6 Hz, 1H), 5.23
(d, J = 10.8 Hz, 1H), 6.14–6.21 (m, 1H), 6.80–7.38 (m, 4H), 7.41
(s, 1H). 13C NMR (CDCl3): 19.9, 21.3, 42.6, 79.0, 108.9, 112.6, 120.5,
125.6, 128.6, 130.9, 142.0, 143.0, 178.7. IR (film): ν (cm−1) 3431,
2927, 1567, 1145, 947, 858, 546, 517 cm−1.Anal. Calcd for C13H15NO2:
C, 71.86; H, 6.96; N, 6.45. Found: C, 71.89; H, 6.88; N, 6.42%.
3-(2-Methylallyl)-3-hydroxy-1,3-dihydro-2H-indol-2-one (3c):
Eluent: hexane–EtOAc (80:20); yield: 98%; colourless crystals;
m.p. 187–188 °C. 1H NMR (CDCl3): δ 1.42 (s, 3H), 2.54 (s, 2H), 2.76
Conclusion
In summary, we have devised a facile and simple procedure for
the synthesis of 3-allyl-3-hydroxyoxindoles from isatins in
PEG-400 using organoindium reagents generated in situ. A
variety of isatins worked well with allyl bromides to give the
target products with excellent yields under mild conditions.
Future studies will focus on synthetic applications of the meth-
ods reported herein and the development of related C-C bond
formation in PEG-400.
(s, 1H), 4.54 (s, 1H), 4.78 (s, 1H), 6.74–7.10 (m, 3H), 7.19 (s, 1H). 13
C
NMR (CDCl3): 22.4, 45.7, 109.6, 115.7, 121.8, 124.0, 129.2, 129.8,
138.0, 139.2, 179.1. IR (film): ν (cm−1) 3329, 2943, 1715, 1616, 1565,
1142, 912, 846, 541. Anal. Calcd for C12H13NO2: C, 70.92, H, 6.45, N,
6.89. Found: C, 70.86; H, 6.42; N, 6.91%.
Experimental
All reagents were used as obtained from commercial sources except
where mentioned. PEG-400 was AR grade and used directly. Indium
with a purity of 99.9% were pressed into flakes and then cut into small
pieces prior to use. Allyl bromide was redistilled for use. Melting
points were determined on an XT-4 electrothermal Micro-melting-
3-Allyl-3-hydroxy-5-methyl-1,3-dihydro-indol-2-one (3d): Eluent:
hexane–EtOAc (80:20); yield: 98%; colourless crystals; m.p. 164–
1
165 °C. H NMR (CDCl3): δ 2.54 (s, 3H), 2.65–2.70 (m, 2H), 2.75
(s, 1H), 5.10–5.14 (m, 2H), 5.64–5.70 (m, 1H), 6.54–7.45 (m, 3H),
7.47 (s, 1H). 13C NMR (CDCl3): 21.5, 42.8, 75.8, 110.0, 119.7, 122.8,
124.2, 129.4, 129.7, 128.9, 140.0, 179.1. IR (film): ν (cm−1) 3338,
2946, 1627, 1564, 921, 853, 514. Anal. Calcd for C12H13NO2: C, 70.92,
H, 6.45, N, 6.89. Found: C, 71.14; H, 6.46; N, 6.90%.
3-(1,1-Dimethylallyl)-3-hydroxy-5-methyl-1,3-dihydro-2H-indol-
2-one (3e): Eluent: hexane–EtOAc (80:20); yield: 97%; colourless
crystals; m.p. 189–190 °C. 1H NMR (CDCl3): δ 1.10 (s, 3H), 1.12 (s,
3H), 2.57, (s, 3H), 2.92 (s, 1H), 5.10-5.11 (m, 2H), 5.63-5.67 (m, 1H),
6.64-7.37 (m, 3H), 7.35 (s, 1H). 13C NMR (CDCl3): 19.9, 21.3, 21.4,
42.7, 79.8, 108.9, 113.1, 120.1, 125.4, 128.0, 130.92, 141.7, 142.4,
178.2. IR (film): ν (cm−1) 3435, 1569, 1148, 957, 864, 541. Anal.
Calcd for C14H17NO2: C, 72.70, H, 7.41, N, 6.06. Found: C, 72.97, H,
7.40; N, 6.08%.
3-(2-Methylallyl)-3-hydroxy-5-methyl-1,3-dihydro-2H-indol-2-one
(3f): Eluent: hexane–EtOAc (80:20); yield: 98%; colourless crystals;
m.p. 188–189 °C. 1H NMR (CDCl3): δ 1.40 (s, 3H), 2.51 (s, 3H), 2.63
(s, 2H), 2.68 (s, 1H), 4.52 (s, 1H), 4.78 (s, 1H), 6.70–7.17 (m, 3H),
7.13 (s, 1H). 13C NMR (CDCl3): 22.5, 22.2, 45.4, 109.1, 115.0, 121.1,
123.5, 129.1, 129.4, 137.5, 139.1, 179.0. IR (film): ν (cm−1) 3359,
1
point apparatus. The H and 13C NMR spectra were recorded on a
Bruker AC-400 (400 MHz) spectrometer with TMS as an internal
standard. IR spectra were obtained on a Perkin-Elmer 683 instrument
as neat films. Microanalyses were measured using a Yanaco MT-3
CHN microelemental analyser.
Indium-mediated allylation of isatin (1); 3-allyl-3-hydroxy-1,3-dihydro-
2H-indol-2-one (3); typical procedure
A mixture of indium powder (2.0 mmol), allyl bromide (2; 3.0 mmol)
and isatin (1; 1.0 mmol) was stirred in PEG-400 (2 mL) at r.t. until all
the isatin has been consumed (confirmed by TLC). The mixture was
extracted with Et2O (3 × 2 mL). The organic extract was washed
with brine, dried (MgSO4), and concentrated under reduced pressure.
Chromatography of the residue eluting with hexane/ethyl acetate
mixtures, gave analytically pure compound 3. Spectroscopic and
analytical data of 3 follow.
3-Allyl-3-hydroxy-1,3-dihydro-2H-indol-2-one (3a): Eluent: hexane–
EtOAc (80:20); yield: 99%; colourless crystals; m.p. 151–152 °C

JOURNAL OF CHEMICAL RESEARCH 2011 393
1712, 1568, 910, 854, 564 cm−1. Anal. Calcd for C13H15NO2: C, 70.92,
H, 6.45, N, 6.89. Found: C, 70.98; H, 6.49; N, 6.91%.
3-Allyl-4-chloro-3-hydroxy-1,3-dihydro-2H-indol-2-one (3g): Eluent:
3.34 (s, 1H), 4.86 (d, J = 10.0 Hz, 1H), 4.96 (d, J = 16.8 Hz, 1H),
5.16–5.21 (m, 1H), 6.76–7.13 (m, 4H), 13C NMR (CDCl3): 77.1, 96.0,
108.9, 118.8, 119.0, 125.5, 128.6, 130.9, 144.1, 177.8. IR (film):
ν (cm−1) 3440, 3130, 1722, 1566, 1143, 95.2, 860, 546, 515 cm−1.
Anal. Calcd for C11H10BrNO2: C, 49.28; H, 3.16; N, 5.22. Found:
C, 49.85; H, 3.58; N, 5.17%.
hexane–EtOAc (80:20); yield: 98%; colourless crystals; m.p.
1
209–211 °C. H NMR (CDCl3): δ 2.80 (s, 1H), 2.84-2.89 (m, 1H),
3.11–3.16 (m, 1H), 5.02 (d, J = 10.8 Hz, 1H), 5.45 (d, J = 17.2 Hz,
1H), 5.44–5.48 (m, 1H), 6.74–7.22 (m, 3H), 7.42 (s, 1H). 13C NMR
(CDCl3): 75.3, 76.5, 108.4, 118.9, 122.3, 126.9, 128.6, 130.7, 130.9,
143.8, 177.6. IR (film): ν (cm−1) 3431, 1721, 1567, 1144, 857, 546,
516. Anal. Calcd for C11H10ClNO2: C, 59.07, H, 4.51, N, 6.26. Found:
C, 59.14; H, 4.50; N, 6.21%.
3-(1,1-Dimethylallyl)-4-chloro-3-hydroxy-1,3-dihydro-2H-indol-2-
one (3h): Eluent: hexane–EtOAc (80:20); yield: 98%; colourless crys-
tals; m.p. 193–194 °C. 1H NMR (CDCl3): δ 1.12 (s, 3H), 1.26 (s, 3H),
3.02 (s, 1H), 5.14–5.21 (m, 2H), 6.05–6.12 (m, 1H), 6.72–7.27 (m,
3H), 7.75 (s, 1H). 13C NMR (CDCl3): 21.0, 23.0, 82.1, 107.8, 112.1,
113.0, 127.4, 130.0, 143.5, 144.3, 178.5. IR (film): ν (cm−1) 3444,
2952, 1640, 1415, 953, 514. Anal. Calcd for C13H14ClNO2: C, 62.03,
H, 5.61, N, 5.56. Found: C, 62.18; H, 5.58; N, 5.52%.
3-(2-Methylallyl)-4-chloro-3-hydroxy-1,3-dihydro-2H-indol-2-one
(3i): Eluent: hexane–EtOAc (80:20); yield: 95%; colourless crystals;
m.p. 232–233 °C. 1H NMR (CDCl3): δ 1.38 (s, 3H), 2.58–2.61
(m, 2H), 2.96–3.00 (m, 1H), 4.20–4.24 (m, 1H), 4.52–4.60 (m, 1H),
6.72–7.20 (m, 3H), 10.46 (s, 1H). 13C NMR (CDCl3): 22.3, 45.4,
109.3, 114.5, 121.1, 123.0, 128.5, 128.5, 137.0, 138.4, 178.3. IR
(film): ν (cm−1) 3431, 2957, 1723, 1567, 1144, 857, 546 cm−1. Anal.
Calcd for C12H12ClNO2: C, 60.64, H, 5.09, N, 5.89. Found: C, 60.84;
H, 5.05; N, 5.87%.
3-(1,1-Dimethylallyl)-4-bromo-3-hydroxy-1,3-dihydro-2H-indol-2-
one (3p): Eluent: hexane–EtOAc (80:20); yield: 93%; colourless
1
crystals; m.p. 174–175 °C. H NMR (CDCl3): δ 1.09 (s, 3H), 1.12
(s, 3H), 2.50 (s, 1H), 5.76–5.91 (m, 2H), 5.99–6.01 (m, 1H),
6.71–7.07 (m, 3H), 10.24 (s, 1H). 13C NMR (CDCl3): 21.2, 23.3, 54.9,
82.4, 108.3, 112.2, 119.5, 126.3, 129.2, 130.2, 143.6, 144.6, 178.7. IR
(film): ν (cm−1) 3414, 1715, 1640, 1139, 1068,952, 863, 515 cm−1.
Anal. Calcd for C13H14BrNO2: C, 52.72; H, 4.76; N, 4.73. Found:
C, 52.87; H, 4.81; N, 4.81%.
3-allyl-5-bromo-3-hydroxy-1,3-dihydro-2H-indol-2-one (3q): Eluent:
hexane–EtOAc (80:20); yield: 96%; colourless crystals; m.p. 217–
218 °C (lit.13 215–217). 1H NMR (CDCl3): δ 2.41–2.62 (m, 3H),
4.93–4.97 (m, 2H), 5.40–5.44 (m, 1H), 6.93 (s, 2H), 7.14–7.22
(m, 2H), 10.39 (s, 1H). 13C NMR (CDCl3): 41.7, 74.9, 110.7, 113.2,
118.5, 126.5,130.7, 130.3,133.0,178.2, 140.0. IR (film): ν (cm−1)
3428, 1721, 1568, 1144, 857, 546, 516 cm−1. Anal. Calcd for
C11H10BrNO2: C, 49.28; H, 3.16; N, 5.22. Found: C, 49.24; H, 3.15;
N, 5.28%.
This project was sponsored by the Jiangxi Provincial Natural
Science Foundation (Nos. 2010GQH0064) and Jiangxi
Provincial Educational Commission Science and Technology
Planning Project (Nos. GJJ11066), we also thank the Analysis
and Testing Centre of Jiangxi Normal University for NMR
measurements.
3-Allyl-5-chloro-3-hydroxy-1,3-dihydro-2H-indol-2-one(3j):Eluent:
hexane–EtOAc (80:20); yield: 99%; colourless crystals; m.p. 177–
1
178 °C. H NMR (CDCl3): δ 2.57–2.61 (m, 1H), 2.70–2.73 (m, 1H),
2.74 (s, 1H), 5.14–5.18 (m, 2H), 5.66–5.72 (m, 1H), 6.78–7.55 (m,
3H), 7.55 (s, 1H). 13C NMR (CDCl3): 64.9, 75.3, 110.8, 116.2, 121.8,
123.0, 125.0, 130.1, 139.0, 140.3, 179.4. IR (film): ν (cm−1) 3414,
2959, 1717, 1568, 1142, 855, 546. Anal. Calcd for C11H10ClNO2: C,
59.07, H, 4.51, N, 6.26. Found: C, 59.14; H, 4.48; N, 6.24%.
Received 17 May 2011; accepted 7 June 2011
Paper 1100701 doi: 10.3184/174751911X13090135895019
Published online: 5 August 2011
3-(1,1-Dimethylallyl)-5-chloro-3-hydroxy-1,3-dihydro-2H-indol-2-
one (3k): Eluent: hexane–EtOAc (80:20); yield: 93%; colourless
1
crystals; m.p. 174–175 °C. H NMR (CDCl3): δ 1.11 (s, 3H), 1.16
References
(s, 3H), 2.84 (s, 1H), 5.12–5.26 (m, 2H), 6.14 (dd, J1 = 10.8 Hz,
J2 = 17.6 Hz, 1H), 6.84–7.30 (m, 3H), 7.43 (s, 1H). 13C NMR (CDCl3):
19.9, 21.2, 42.7, 78.7, 108.9, 120.3, 127.0, 129.9, 132.9, 142.6, 143.7,
178.6. IR (film): ν (cm−1) 3391, 1711, 1567, 1144, 858, 546. Anal.
Calcd for C12H12ClNO2: C, 60.64, H, 5.09, N, 5.89. Found: C, 60.95;
H, 5.12; N, 5.87%.
1
Y. Kamano, H.P. Zhang, Y. Ichihara, H. Kizu, K. Komiyama and
G.R. Pettit, Tetrahedron Lett., 1995, 36, 2783.
2
3
H.B. Rasmussen and J.K. MacLeod, J. Nat. Prod., 1997, 60, 1152.
W. Balk-Bindseil, E. Helmke, H. Weyland and H. Laatsch, Liebigs Ann.,
1995, 1291.
4
5
6
7
K. Monde, K. Sasaki, A. Shirata and M. Tagusuki, Phytochemistry, 1991,
30, 2915.
H. Suzuki, H. Morita, M. Shiro and M. Kobayashi, Tetrahedron, 2004, 60,
2489.
A. Frechard, N. Fabre, C. Pean, S. Montaut, M.T. Fauvel, P. Rollin and
I. Fouraste, Tetrahedron Lett., 2001, 42, 9015.
J. Kohno, Y. Koguchi, M. Nishio, K. Nakao, M. Kuroda, R. Shimisu,
T. Ohnuki and S. Komatsubara, J. Org. Chem., 2000, 65, 990.
C. Marti and E.M. Carreira, Eur. J. Org. Chem., 2003, 2209.
H. Lin and S.J. Danishefsky, Angew. Chem., Int. Ed., 2003, 42, 36.
3-Allyl-6-chloro-3-hydroxy-1,3-dihydro-2H-indol-2-one (3l): Eluent:
hexane–EtOAc (80:20); yield: 99%; colourless crystals; m.p. 202–
1
203 °C. H NMR (CDCl3): δ 2.56–2.62 (m, 1H), 2.70–2.74 (m, 1H),
2.83 (s, 1H), 5.12–5.16 (m, 2H), 5.66–5.69 (m, 1H), 6.88–7.30 (m,
3H), 7.59 (s, 1H). 13C NMR (CDCl3): 43.5, 79.9, 110.2, 116.1, 122.3,
127.2, 127.3, 135.3, 141.3, 142.1, 179.2. IR (film): ν (cm−1) 3351,
1722, 1147, 861, 546. Anal. Calcd for C11H10ClNO2: C, 59.07, H, 4.51,
N, 6.26. Found: C, 59.57; H, 4.50; N, 6.27%.
8
9
3-(1,1-Dimethylallyl)-6-chloro-3-hydroxy-1,3-dihydro-2H-indol-2-
one (3m): Eluent: hexane–EtOAc (80:20); yield: 96%; colourless
10 C.V. Galliford and K.A. Scheidt, Angew. Chem., Int. Ed., 2007, 46, 8748.
11 B.M. Trost and M.K. Brennan, Synthesis, 2009, 3003.
12 S. Araki, H. Ito and Y. Butsugan, J. Org. Chem., 1988, 53, 1831.
13 J. Podlech and T.C. Maier, Synthesis, 2003, 633.
14 Z. Du and Y. Li, Prog. Chem., 2010, 22, 71.
15 V. Nair, S. Ros and C.N. Jayan, Tetrahedron, 2001, 57, 9453.
16 V. Nair, S. Ros and C.N. Jayan, J. Chem. Res., Synop., 2001, 551.
17 J.H. Gong, K.Y. Lee, J.S. Son and J.N. Kim, Bull. Kor. Chem. Soc., 2003,
24, 507.
1
crystals; m.p. 213–234 °C. H NMR (CDCl3): δ 1.11 (s, 3H), 1.16
(s, 3H), 2.84 (s, 1H), 5.12–5.26 (m, 2H), 6.14 (dd, J1 = 10.8 Hz,
J2 = 17.6 Hz, 1H), 6.84–7.30 (m, 3H), 7.43 (s, 1H). 13C NMR (CDCl3):
19.9, 21.2, 42.7, 78.7, 108.9, 120.3, 127.0, 129.9, 132.9, 142.6, 143.7,
178.6. IR (film): ν (cm−1) 3391, 1711, 1567, 1144, 858, 546 cm−1.
Anal. Calcd for C13H14ClNO2: C, 62.03, H, 5.61, N, 5.56. Found:
C, 62.15; H, 5.59; N, 5.54%.
18 B. Alcaide, P. Almendros and R. Rodrĺguez-Acebes, J. Org. Chem., 2005,
3-(2-Methylallyl)-6-chloro-3-hydroxy-1,3-dihydro-2H-indol-2-one
(3n): Eluent: hexane–EtOAc (80:20); yield: 97%; colourless crystals;
m.p. 212–213 °C. 1H NMR (CDCl3): δ 1.57 (s, 3H), 2.67 (s, 2H), 2.80
70, 3198.
19 J. Chen, S.K. Spear, J.G. Huddleston and R.D. Rogers, Green Chem., 2005,
7, 64.
20 S. Chandrasekhar, C. Narsihmulu, S.S. Sultana and N.R. Reddy, Org. Lett.,
(s, 1H), 4.67 (s, 1H), 4.84 (s, 1H), 6.87–7.29 (m, 3H), 7.31 (s, 1H). 13
C
NMR (CDCl3): 24.0, 46.1, 110.8, 116.6, 122.9, 126.0, 130.5, 130.8,
139.5.0, 139.9, 180.6. IR (film): ν (cm−1) 3431, 1567 , 1144, 945, 857,
546 cm−1. Anal. Calcd for C12H12ClNO2: C, 60.64, H, 5.09, N, 5.89.
Found: C, 60.72; H, 5.05; N, 5.86%.
2002, 4, 4399.
21 V.V. Namboodiri and R.S. Varma, Green Chem., 2001, 3, 146.
22 Z. Hou, N. Thetssen and W. Leitner, Green Chem., 2007, 9, 127.
23 R. Kumar, P. Chaudhary, S. Nimesh and R. Chandra, Green Chem., 2006,
8, 356.
3-Allyl-4-bromo-3-hydroxy-1,3-dihydro-2H-indol-2-one (3o): Eluent:
hexane–EtOAc (80:20); yield: 96%; colourless crystals; m.p. 232–
24 W. Wang, S. Lu, P. Yang, X. Han and Y. Zhou, J. Am. Chem. Soc., 2003,
1
233 °C. H NMR (CDCl3): δ 2.50–2.58 (m, 1H), 3.03–3.08 (m, 1H),
125, 10536.

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