ortho-Allylation of 2-Arylindazoles with Vinyl Cyclic Carbonate and Diallyl Carbonate via Manganese-Catalyzed C?H Bond Activation

Article abstract of DOI:10.1002/adsc.202100627

A manganese-catalyzed directed C?H allylation of 2-arylindazole has been developed. Both vinyl cyclic carbonate and diallyl carbonate are effectively used for ortho-allylation via decarboxylation. The mechanism was investigated and possibly Mn(I)-catalyzed C?H bond activation is not involved in the rate-determining step. (Figure presented.).

Full text of DOI:10.1002/adsc.202100627

Title: ortho-Allylation of 2-Arylindazoles with Vinyl Cyclic Carbonate
and Diallyl Carbonate via Manganese-Catalyzed CꢀH Bond
Activation
Authors: Asim Kumar Ghosh, Krishna Kanta Das, and Alakananda
Hajra
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To be cited as: Adv. Synth. Catal. 10.1002/adsc.202100627
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10.1002/adsc.202100627
Advanced Synthesis & Catalysis
UPDATE
DOI: 10.1002/adsc.201((will be filled in by the editorial staff))
ortho-Allylation of 2-Arylindazoles with Vinyl Cyclic Carbonate
and Diallyl Carbonate via Manganese-Catalyzed CH Bond
Activation
Asim Kumar Ghosh,[a] Krishna Kanta Das,[a] and Alakananda Hajra*[a]
[a]Department of Chemistry, Visva-Bharati (A Central University), Santiniketan 731235, India
Email: alakananda.hajra@visva-bharati.ac.in
Received: ((will be filled in by the editorial staff))
Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/adsc.201######. ((Please
delete if not appropriate))
substituted 2H-indazole moieties exhibit valuable
of 2-arylindazole has been developed. Both vinyl cyclic pharmacological activities, such as HIV-protease
Abstract. A manganese-catalyzed directed CH allylation
carbonate and diallyl carbonate are effectively used for
ortho-allylation via decarboxylation. The mechanism was
investigated and possibly Mn(I)-catalyzed CH bond
activation is not involved in the rate-determining step.
inhibition and antimicrobial, antitumor, anti-
inflammatory, and anticancer properties.[12] There are
several marketed drugs, such as bendazac (tyrosine
kinase inhibitor, votrient),[13a] gamendazole,[13b] and
pazopanib,[13c] etc., containing indazole moiety.
Moreover, indazole derivatives have shown photo-
physical properties and are applied as fluorescent
probes.[14] Hence, the synthesis and functionalization
of indazoles have attracted considerable attention.[15-
Keywords: CH activation; manganese; allylation;
decarboxylation; diastereoselective.
17]
Considering the importance of allyl group and
Introduction
indazole moiety, it is highly desirable to develop a
useful method to synthesis hybrid compounds
containing the two pharmacophores. In this article,
we have reported a manganese-catalyzed ortho-
selective CH allylation of 2-arylindazoles with vinyl
cyclic carbonate as well as diallyl carbonate (Scheme
1).
In the past decades, transition metal-catalyzed
CH bond activation has emerged as an endurable
method to improve step- and atom-economy in
organic synthesis.[1] Precious 4d and 5d transition
metals such as Pd,[2a] Rh,[2b] Ru,[2c] and Ir[2d] are
extensively used in the traditional CH
functionalizations. Nowadays, earth-abundant 3d
transition metals with lower toxicity have drawn
much attention.[3] In this context, manganese has
proved to be an efficient catalyst because of its low-
cost and non-toxic nature.[4] Many research groups,
such as those of Wang,[5] Ackermann,[6] Kuninobu,
Takai,[7] and Glorius,[8] have made pioneering
contributions in the use of Mn catalytic technology.
The incorporation of allyl groups in a molecule has
drawn great interest due to the extensive utilization of
allylated compounds in organic synthesis,
Scheme 1. Indazole-directed CH allylation
Results and Discussion
chemistry.[9]
Initially, we started our investigation with coupling
between 2-(p-tolyl)-2H-indazole (1b) and 4-vinyl-
1,3-dioxolan-2-one (2) in presence of 5 mol%
Mn2(CO)10 as a catalyst and 20 mol% NaOAc as an
additive in 1,4-dioxane at 100 °C under N2
atmosphere. To our delight, allylated product 3b was
obtained in 90% yield with high diastereoselectivity
after 10 h (Table 1, entry 1). Manganese (II) salts
were examined but the desired product was not
observed (Table 1, entries 2 and 3). Moreover,
MnBr(CO)5 was tested as a catalyst and afforded the
product in 85% yield (Table 1, entry 4). The reaction
was carried out without additive but unsatisfactory
biochemistry,
and
medicinal
Traditionally, allylation is performed by metal-
catalyzed cross-coupling[10a] and Friedel-Crafts
reactions in presence of a Lewis acid.[10b] However,
limited substrate scope, low regioselectivity,
multistep reactions, and over allylation have
restricted their application. Allylation through ortho-
CH activation will be a more advantageous
method.[11]
Indazole, an important biologically active N-
containing heterocycle, has a variety of applications
in medicinal chemistry and material sciences. The
1
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10.1002/adsc.202100627
Advanced Synthesis & Catalysis
result was obtained (Table 1, entry 5). Furthermore,
the use of additives other than NaOAc was screened
but no improvement of the yield was observed (Table
1, entries 6-9). A variety of solvents were also
examined (Table 1, entries 10-14) such as
chlorobenzene, CH3CN, THF, 1,2-DCE and TFE.
Among them, 1,4-dioxane was found to be the
appropriate solvent (Table 1, entry 1). Besides, no
desired product was formed in absence of Mn2(CO)10
catalyst (Table 1, entry 15). The reaction was
observed to be air sensitive (Table 1, entry 16) and an
inert atmosphere was needed. Lower yield of the
product was observed with both increasing and
decreasing the reaction temperature (Table 1, entry
17). In addition, no further improvement of the yield
and no difunctionalization product were obtained
upon increasing the quantity of substrate 2 (Table 1
entry 18). Finally, the optimized reaction conditions
was accomplished by using 1b (0.2 mmol), 2 (0.3
mmol), 5 mol% of Mn2(CO)10, and 20 mol% of
NaOAc in 1,4-dioxane (1.5 mL) for 10 h at 100 °C
(Table 1, entry 1).
Table 1. Optimization of the reaction conditions.[a]
Entry
Catalyst
5 mol%
Additives
Solvent
Yield (%)
E/Z
(20 mol%)
(1.5 mL)
Ratio
1
2
3
4
5
6
7
8
Mn2(CO)10
Mn(OAc)2
MnCl2
NaOAc
NaOAc
NaOAc
NaOAc
-
K2CO3
Na2CO3
Et3N
1,4-dioxane
1,4-dioxane
1,4-dioxane
1,4-dioxane
1,4-dioxane
1,4-dioxane
1,4-dioxane
1,4-dioxane
1,4-dioxane
chlorobenzene
CH3CN
90
nr
nr
85
35
32
41
26
74
nr
6.9
-
-
6.1
-
-
-
-
MnBr(CO)5
Mn2(CO)10
Mn2(CO)10
Mn2(CO)10
Mn2(CO)10
Mn2(CO)10
Mn2(CO)10
Mn2(CO)10
9
10
11
KOAc
NaOAc
NaOAc
5.8
-
-
nr
12
13
14
Mn2(CO)10
Mn2(CO)10
Mn2(CO)10
NaOAc
NaOAc
NaOAc
THF
1,2-DCE
TFE
Trace
79
89
-
5.1
6.9
15
16
17
18
-
NaOAc
NaOAc
NaOAc
NaOAc
1,4-dioxane
1,4-dioxane
1,4-dioxane
1,4-dioxane
nr
-
-
6.9
6.7
Mn2(CO)10
Mn2(CO)10
Mn2(CO)10
Trace[b]
85[c], 78[d]
87[e]
[a] Reaction conditions: All reactions were carried out with 1b (0.2 mmol), 2 (0.3 mmol), Mn2(CO)10 (5 mol%), NaOAc (20
mol%), solvent (1.5 mL) for 10 h at 100 °C under N2.
[b] Under air.
[c] Stirred at 120 °C,
[d] Stirred at 80 °C,
[e] 3.0 Equiv of 2 was used. nr = no reaction.
With the optimized reaction conditions in hand, we
have evaluated their utility and limitations in the
present manganese-catalyzed CH allylation of 2-
arylindazoles (Scheme 2). In the presence of electron-
donating groups like -Me and -OMe at phenyl ring of
2-arylindazole, the corresponding products were
obtained in excellent yield (3b and 3c). Halogen like
-F, -Cl and -Br substituted substrates gave moderate
to good yields of the desired product (3d-3f, 3h and
3k). An electron-withdrawing group like -COOEt
(1g) also produced the desired product (3g) with 67%
yield. Disubstituted indazoles (1i-1n) were examined
and effectively gave the ortho-allylation product
without any difficulties (3i-3n). Moreover, 1-phenyl-
1H-pyrazole (1o) was also reacted under the
optimized reaction conditions and gave the desired
product (3o) in 61% yield. On the other hand, ortho-
and meta-substituted substrates did not give the
expected product possibly due to the difficulty of the
formation of five membered manganacyclic
intermediate.
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10.1002/adsc.202100627
Advanced Synthesis & Catalysis
Scheme 2. Substrate scope of indazoles. Reaction conditions: 1 (0.2 mmol), 2 (0.3 mmol) in presence of Mn2[CO]10 (5
mol%), NaOAc (20 mol%), 1,4-dioxane (1.5 mL) at 100 °C for 10 h under N2.
We have extended the present methodology using
diallyl carbonate (4) for allylation as depicted in
Scheme 3. The 2-arylindazole containing both
electron-rich (-Me, -OMe) and electron-deficient (-F,
-Cl, and -Br) groups on the phenyl ring of indazole
reacted with diallyl carbonate gave the corresponding
products 5b-5f in 40-88% yields. The introduction of
-F and -Cl groups at the C-5 position of the indazole
ring did not affect the reaction efficiency (5h, 5k).
Moreover, disubstituted 2-arylindazole was reacted
smoothly to give the expected products 5i and 5n in
moderate yields. Interestingly, 1-phenyl-1H-pyrazole,
2-phenyl-4,5-dihydrooxazole, and 2-phenylpyridine
were suitable substrates for this ortho-allylation
reaction and gave the desired products (5o-5q) in 66-
77% yields. However, dimethallyl carbonate was
unable to provide the desired product under the
present
reaction
conditions.
Scheme 3. Substrate scope of indazoles. Reaction conditions: 1 (0.2 mmol), 4 (0.3 mmol) in presence of Mn2(CO)10 (5
mol%), NaOAc (20 mol%), 1,4-dioxane (1.5 mL) at 100 °C for 24 h under N2.
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10.1002/adsc.202100627
Advanced Synthesis & Catalysis
In order to show the synthetic applicability of this
On the basis of control experiments and previous
process, a gram scale reaction was carried out literature reports,[6b,8a] a plausible reaction pathway is
between 2-(p-tolyl)-2H-indazole (1b, 5 mmol) and 4- proposed in Scheme 6. Initially, base-assisted
vinyl-1,3-dioxolan-2-one (2, 7.5 mmol) under the cyclomanganation of 2-(p-tolyl)-2H-indazole (1b)
optimized reaction conditions as well as in the normal forms a five membered manganacycle A. Next,
laboratory setup. Gratifyingly, the desired product coordination of 4-vinyl-1,3-dioxolan-2-one (2) with A
was obtained in 82% yield (Scheme 4).
leads to seven-membered manganacyclic intermediate
B. It undergoes β-oxygen elimination to afford
intermediate C through CO2 gas evolution which
accelerates the ring-opening of cyclic carbonate.
Finally, the protonation of the C provides the desired
product 3b and regenerate the active Mn(I) complex.
Scheme 4. Scale-up synthesis of 3b.
To explore the mechanistic route of the reaction, a
series of controlled experiments were performed
(Scheme 5). Firstly, H/D exchange experiment was
carried out by using 1b with D2O as a co-solvent
1
under our standard reaction condition. The H NMR
analysis showed that 100% deuterium was
impregnated at the ortho-position of the phenyl ring
in 1b-d2 which indicating that
a
reversible
deprotonative CH bond activation step might be
involved in the reaction (Scheme 5a). The
intermolecular competition experiment (KIE = 1.62,
Scheme 5b) and the parallel experiment (kH/kD = 1.48,
Scheme 5c) indicate that Mn-catalyzed CH bond
activation step may not be involved in the rate-
determining step. Finally, the reaction was carried out
in the presence of radical scavengers like 2,6-di-
Scheme 6. Plausible mechanistic pathway.
tertbutyl-4-methylphenol (BHT)
and 2,2,6,6-
tetramethyl-1-piperidinyloxy (TEMPO), but the
reaction efficiency did not alter which indicates that Conclusion
the reaction may not be involved in radical path
(Scheme 5d).
In conclusion, we have reported a [Mn2(CO)10]
catalyzed directed CH allylation of 2-arylindazoles
with both vinyl cyclic carbonate and diallyl carbonate
under mild reaction conditions. The present reaction
could be carried on a gram scale. Moreover, this
method is associated with high functional groups
tolerance. The kinetics studies have been conducted
and it was observed that the CH bond activation step
may not be involved in the rate-determining step. To
the best of our knowledge, this is the first report on
the directed ortho-allylation of 2-arylindazole. We
believe that this protocol of Mn-catalyzed directed
C(sp2)H allylation of 2-arylindazoles will achieve
significant applications in academic and industrial
research.
Experimental section
General Information: All reagents were purchased from
commercial sources and used without further purification.
1H NMR spectra were determined on 400 MHz
spectrometer as solutions in CDCl3. Chemical shifts are
expressed in parts per million (δ) and the signals were
reported as s (singlet), d (doublet), t (triplet), m (multiplet)
and coupling constants (J) were given in Hz. 13C{1H}
NMR spectra were recorded at 100 MHz in CDCl3.
Scheme 5. Control Experiments.
1
Chemical shifts are referenced to CDCl3 (δ = 7.26 for H
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10.1002/adsc.202100627
Advanced Synthesis & Catalysis
and δ = 77.16 for 13C{1H} NMR) as internal standard. TLC 1.72 (br, 1H); 13C{1H} NMR (100 MHz, CDCl3): Major
1
was done on silica gel coated glass slide. All solvents were isomer : δ 162.88 (C-F, JC-F = 248.0 Hz), 149.41, 139.07,
3
dried and distilled before use. All reactions involving 136.16, 131.77, 128.87, 128.74 (C-F, JC-F = 8.0 Hz),
3
moisture sensitive reactants were executed using oven 126.85, 124.97, 122.60 (C-F, JC-F = 11.0 Hz), 120.37,
2
2
dried glassware. All the reactions were heated in oil bath. 117.90, 117.29 (C-F, JC-F = 23.0 Hz), 114.13 (C-F, JC-F
=
All 2-arylindazoles were prepared by the reported methods. 23.0 Hz), 63.16, 34.28; Minor isomer : δ 164.23, 138.99,
[17]
136.01, 130.81, 127.02, 125.14, 122.05, 117.82, 116.96,
114.17, 113.94, 58.05, 29.41; Four peaks are missing due
to C-F coupling and overlap; Anal. Calcd for C17H15FN2O:
Typical Experimental Procedure for the Synthesized
C, 72.33; H, 5.36; N, 9.92%; Found: C, 72.12; H, 5.33; N,
Compounds (3a-3o): A mixture of 2-(p-tolyl)-2H-indazole
10.01%.
(0.2 mmol, 41.6 mg) (1b), Mn2(CO)10 (5 mol%, 3.8 mg),
and NaOAc (20 mol%, 3.2 mg) was taken in an oven dried
screw-capped reaction tube. Then the reaction vessel was 4-(5-Chloro-2-(2H-indazol-2-yl)phenyl)but-2-en-1-ol
evacuated and filled with nitrogen for three times. After (3e): Yellow gummy mass (68%, 40.5 mg); Rf = 0.50 (PE /
that, 4-vinyl-1,3-dioxolan-2-one (2) (0.3 mmol) and 1,4- EA = 70 : 30); 1H NMR (400 MHz, CDCl3): δ 8.06 (s, 1H),
dioxane (1.5 mL) were added, and the resultant mixture 7.79-7.70 (m, 2H), 7.39-7.33 (m, 4H), 7.17-7.13 (m, 1H),
was stirred at 100 °C in oil bath for 10 h. After completion 5.64-5.51 (m, 1H), 5.49-5.41 (m, 1H), 3.96 (d, J = 5.2 Hz,
of the reaction (TLC), the reaction was cooled to room 2H), 3.36-3.29 (m, 2H), 1.69 (br, 1H); 13C{1H} NMR (100
temperature and extracted with ethyl acetate. The organic MHz, CDCl3): Major isomer : δ 149.54, 138.09, 135.38,
phase was dried over anhydrous Na2SO4. The crude residue 131.78, 130.70, 130.49, 128.74, 128.31, 127.43, 126.93,
was obtained after evaporating the solvent in vacuum and 124.79, 122.64, 122.13, 120.38, 117.95, 63.21, 34.24;
was purified by column chromatography on silica gel using Minor isomer : δ 138.59, 135.56, 132.26, 130.78, 128.66,
a mixture of petroleum ether and ethyl acetate (70:30) as an 127.34, 127.11, 124.98, 122.75, 121.45, 117.87, 58.12,
eluting solvent to afford the pure product 3b (50 mg, 90%) 29.40; Four peak are missing due to overlap; Anal. Calcd
as a yellow gummy mass.
for C17H15ClN2O: C, 68.34; H, 5.06; N, 9.38%; Found: C,
68.54; H, 5.11; N, 9.49%.
4-(2-(2H-Indazol-2-yl)phenyl)but-2-en-1-ol
(3a):
Colorless gummy mass (92%, 48.5 mg); Rf = 0.50 (PE / EA 4-(5-Bromo-2-(2H-indazol-2-yl)phenyl)but-2-en-1-ol
1
= 75 : 25); H NMR (400 MHz, CDCl3): δ 8.08 (s, 1H), (3f): Yellow gummy mass (65%, 44 mg); Rf = 0.50 (PE /
7.78-7.34 (m, 2H), 7.40-7.37 (m, 5H), 7.14 (s, 1H), 5.63- EA = 70 : 30); 1H NMR (400 MHz, CDCl3): δ 8.06 (s, 1H),
5.36 (m, 2H), 3.90 (s, 2H), 3.34-3.30 (m, 2H), 1.84 (br, 7.79-7.70 (m, 2H), 7.54-7.48 (m, 2H), 7.36-7.26 (m, 2H),
1H); 13C{1H} NMR (100 MHz, CDCl3): Major isomer : δ 7.15 (t, J = 7.6 Hz, 1H), 5.63-5.39 (m, 2H), 3.95 (d, J = 4.4
149.31, 140.03, 136.16, 131.02, 130.79, 130.09, 129.78, Hz, 2H), 3.35-3.28 (m, 2H), 2.28 (br, 1H); 13C{1H} NMR
129.57, 127.25, 127.05, 126.69, 124.80, 122.38, 120.39, (100 MHz, CDCl3): Major isomer : δ 149.45, 138.99,
117.90, 63.22, 34.35; Minor isomer : δ 139.85, 136.67, 138.30, 133.64, 131.73, 130.76, 130.41, 128.64, 128.53,
130.50, 129.90, 129.70, 129.62, 127.17, 126.86, 124.97, 126.98, 124.80, 123.50, 122.64, 120.38, 117.86, 63.12,
122.50, 122.01, 117.83, 58.04, 29.45; Three peaks are 34.16; Minor isomer : δ 149.55, 138.83, 138.78, 138.24,
missing due to overlap; Anal. Calcd for C17H16N2O: C, 133.43, 130.32, 128.49, 127.15, 124.98, 123.66, 122.75,
77.25; H, 6.10; N, 10.60%; Found: C, 77.43; H, 6.14; N, 122.07, 117.78, 58.03, 29.28; Two peaks are missing due to
10.50%.
overlap; Anal. Calcd for C17H15BrN2O: C, 59.49; H, 4.41;
N, 8.16%; Found: C, 59.66; H, 4.43; N, 8.09%.
4-(2-(2H-Indazol-2-yl)-5-methylphenyl)but-2-en-1-ol
(3b): Yellow gummy mass (90%, 50 mg); Rf = 0.50 (PE / Ethyl
3-(4-hydroxybut-2-en-1-yl)-4-(2H-indazol-2-
EA = 70 : 30); 1H NMR (400 MHz, CDCl3): δ 8.05-8.04 (m, yl)benzoate (3g): Colorless gummy mass (67%, 45 mg); Rf
1H), 7.79-7.75 (m, 1H), 7.72-7.69 (m, 1H), 7.35-7.30 (m, = 0.50 (PE / EA = 55 : 45); 1H NMR (400 MHz, CDCl3): δ
2H), 7.28-7.24 (m, 1H), 7.17-7.10 (m, 3H), 5.62-5.25 (m, 8.12 (s, 1H), 8.10-8.02 (m, 2H), 7.79 (t, J = 8.4 Hz, 1H),
1H), 3.93-3.89 (m, 2H), 3.29-3.23 (m, 2H), 2.39 (s, 3H), 7.74-7.71 (m, 1H), 7.52-7.47 (m, 1H), 7.38-7.33 (m, 1H),
2.24 (br, 1H); 13C{1H} NMR (100 MHz, CDCl3): Major 7.18-7.13 (m, 1H), 5.68-5.40 (m, 2H), 4.44-4.39 (m, 2H),
isomer : δ 149.16, 139.62, 137.54, 135.74, 131.24, 130.89, 3.99-3.93 (m, 2H), 3.49-3.43 (m, 2H), 1.72 (br, 1H), 1.42 (t,
129.69, 127.79, 126.77, 126.56, 124.86, 122.23, 121.90, J = 7.2 Hz, 3H); 13C{1H} NMR (100 MHz, CDCl3): Major
120.33, 117.78, 63.10, 34.25, 21.28; Minor isomer : δ isomer : δ 165.85, 149.67, 143.49, 136.24, 132.36, 132.05,
149.26, 139.78, 137.36, 136.25, 132.17, 130.97, 129.98, 131.51, 130.55, 129.17, 128.57, 127.23, 127.10, 124.66,
129.56, 127.70, 126.72, 125.02, 122.34, 121.38, 117.72, 122.74, 120.43, 118.01, 63.21, 61.61, 34.53, 14.45; Minor
57.91, 29.30; Two peaks are missing due to overlap; isomer : δ 165.80, 149.74, 143.28, 136.87, 131.35, 129.08,
HRMS (ESI-TOF) m/z: [M + H]+ Calcd for C18H19N2O: 128.48, 127.05, 124.87, 122.84, 122.20, 117.91, 58.22,
279.1492; found: 279.1495.
29.72; Six peaks are missing due to overlap; Anal. Calcd
for C20H20N2O3: C, 71.41; H, 5.99; N, 8.33%; Found: C,
71.23; H, 5.95; N, 8.41%.
4-(2-(2H-Indazol-2-yl)-5-methoxyphenyl)but-2-en-1-ol
(3c): Colorless gummy mass (72%, 42 mg); Rf = 0.50 (PE /
EA = 65 : 35); 1H NMR (400 MHz, CDCl3): δ 7.89 (s, 1H), 4-(2-(5-Fluoro-2H-indazol-2-yl)phenyl)but-2-en-1-ol
7.63-7.55 (m, 2H), 7.19 (t, J = 8.8 Hz, 2H), 6.99 (t, J = 8.4 (3h): Colorless gummy mass (85%, 47.9 mg); Rf = 0.45
Hz, 1H), 6.72-6.69 (m, 2H), 5.48-5.20 (m, 2H), 3.79-3.76 (PE / EA = 75 : 25); 1H NMR (400 MHz, CDCl3): δ 8.04 (s,
(m, 2H), 3.70 (s, 3H), 3.14-3.07 (m, 2H), 2.32 (br, 1H); 1H), 7.77-7.73 (m, 1H), 7.46-7.34 (m, 4H), 7.30-7.28 (m,
13C{1H} NMR (100 MHz, CDCl3): Major isomer : δ 1H), 7.17-7.12 (m, 1H), 5.66-5.36 (m, 2H), 3.97-3.93 (m,
160.21, 149.00, 137.73, 133.10, 131.18, 129.31, 128.58, 2H), 3.36-3.29 (m, 2H), 1.76 (br, 1H); 13C{1H} NMR (100
1
128.18, 126.66, 125.19, 122.28, 120.34, 117.67, 115.54, MHz, CDCl3): Major isomer : δ 158.73 (C-F, JC-F = 239.0
111.99, 63.05, 55.64, 34.46; Minor isomer : δ 160.31, Hz), 146.76, 139.88, 136.05, 131.01, 130.87, 129.93,
3
149.16, 138.16, 132.18, 130.32, 129.21, 127.88, 126.77, 129.77, 127.34, 126.97, 124.89 (C-F, JC-F = 9.0 Hz),
3
2
126.26, 125.29, 122.36, 121.87, 121.38, 115.86, 111.99, 119.94 (C-F, JC-F = 5.0 Hz), 118.34 (C-F, JC-F = 28.0 Hz),
57.91, 29.47; One peak is missing due to overlap; Anal. 102.76 (C-F, 2JC-F = 25.0 Hz), 63.27, 34.31; Minor isomer :
1
Calcd for C18H18N2O2: C, 73.45; H, 6.16; N, 9.52%; Found: δ 158.68 (C-F, JC-F = 240.0 Hz), 146.85, 139.69, 136.56,
3
C, 73.26; H, 6.19; N, 9.44%.
130.58, 130.03, 129.71, 127.26, 120.04 (C-F, JC-F = 5.0
2
Hz), 118.50 (C-F, JC-F = 29.0 Hz), 58.08, 29.42; Five
peaks are missing due to C-F coupling and overlap; HRMS
(ESI-TOF) m/z: [M + H]+ Calcd for C17H16FN2O:
283.1241; found: 283.1244.
4-(5-Fluoro-2-(2H-indazol-2-yl)phenyl)but-2-en-1-ol
(3d): Colorless gummy mass (86%, 48.5 mg); Rf = 0.55
(PE / EA = 70 : 30); 1H NMR (400 MHz, CDCl3): δ 8.05 (s,
1H), 7.77-7.71 (m, 2H), 7.40-7.35 (m, 2H), 7.15-7.05 (m,
3H), 5.64-5.42 (m, 2H), 3.95 (s, 2H), 3.32-3.26 (m, 2H),
This article is protected by copyright. All rights reserved.

10.1002/adsc.202100627
Advanced Synthesis & Catalysis
4-(2-(5-Fluoro-2H-indazol-2-yl)-5-methylphenyl)but-2-
122.35, 115.71, 112.07, 58.11, 29.56; Ten peaks are
en-1-ol (3i): Yellow gummy mass (61%, 36 mg); Rf = 0.50 missing due to overlap; HRMS (ESI-TOF) m/z: [M + H]+
(PE / EA = 72 : 28); 1H NMR (400 MHz, CDCl3): δ 8.01 (d, Calcd for C18H18ClN2O2: 329.1051; found: 329.1042.
J = 8.4 Hz, 1H), 7.77-7.21 (m, 1H), 7.30-7.24 (m, 2H),
7.19-7.11 (m, 3H), 5.65-5.36 (m, 2H), 3.96-3.93 (m, 2H),
4-(2-(5-Methoxy-2H-indazol-2-yl)-5-methylphenyl)but-
2-en-1-ol (3n): Colorless gummy mass (90%, 55.4 mg); Rf
3.31-3.24 (m, 2H), 2.41 (s, 3H), 1.77 (br, 1H); 13C{1H}
= 0.50 (PE / EA = 60 : 40); 1H NMR (400 MHz, CDCl3): δ
7.99 (s, 1H), 7.74 (s, 1H), 7.34-7.12 (m, 4H), 6.99 (s, 1H),
5.67-5.49 (m, 2H), 4.01 (s, 2H), 3.92 (s, 3H), 3.38-3.33 (m,
2H), 2.48 (s, 3H), 2.21 (br, 1H); 13C{1H} NMR (100 MHz,
CDCl3): Major isomer : δ 155.38, 146.10, 139.42, 137.67,
135.73, 131.22, 130.83, 129.94, 127.78, 126.77, 123.85,
121.72, 121.55, 119.19, 96.37, 63.23, 55.45, 34.27, 21.28;
Minor isomer : δ 155.46, 139.60, 137.49, 136.24, 130.96,
129.79, 127.69, 124.03, 121.88, 119.16, 58.00, 29.34;
Seven peaks are missing due to overlap; Anal. Calcd for
C19H20N2O2: C, 74.00; H, 6.54; N, 9.08%; Found: C, 73.85;
H, 6.59; N, 8.99%.
NMR (100 MHz, CDCl3): Major isomer : δ 158.63 (C-F,
1JC-F = 238.0 Hz), 146.68, 139.83, 137.49, 135.67, 131.34,
3
130.87, 129.91, 127.87 (C-F, JC-F = 8.0 Hz), 126.73,
3
124.95 (C-F, JC-F = 8.0 Hz), 121.15, 120.01, 118.34 (C-F,
2JC-F = 19.0 Hz), 102.76 (C-F, 2JC-F = 22.0 Hz), 63.29, 34.28,
21.35; Minor isomer : δ 146.77, 140.00, 137.29, 136.17,
3
132.23, 131.08, 125.13 (C-F, JC-F = 8.0 Hz), 121.48,
3
2
121.26, 119.94 (C-F, JC-F = 5.0 Hz), 118.17 (C-F, JC-F
=
29.0 Hz), 102.76 (C-F, 2JC-F = 24.0 Hz), 58.06, 29.34; Four
peaks are missing due to C-F coupling and overlap; Anal.
Calcd for C18H17FN2O: C, 72.95; H, 5.78; N, 9.45%;
Found: C, 72.81; H, 5.73; N, 9.56%.
4-(5-Chloro-2-(5-fluoro-2H-indazol-2-yl)phenyl)but-2-
en-1-ol (3j): Colorless gummy mass (52%, 32.8 mg); Rf =
4-(2-(5-Methoxy-2H-indazol-2-yl)-5-methylphenyl)but-
2-en-1-ol (3o): Colorless gummy mass (61%, 26 mg); Rf =
1
1
0.55 (PE / EA = 65 : 35); H NMR (400 MHz, CDCl3): δ
0.50 (PE / EA = 75 : 25); H NMR (400 MHz, CDCl3): δ
8.02 (s, 1H), 7.77-7.24 (m, 1H), 7.39-7.33 (m, 3H), 7.29-
7.27 (m, 1H), 7.17-7.12 (m, 1H), 5.64-5.43 (m, 2H), 3.98
(d, J = 5.6 Hz, 2H), 3.35-3.28 (m, 2H), 1.78 (br, 1H);
13C{1H} NMR (100 MHz, CDCl3): Major isomer : δ
7.72 (d, J = 11.2 Hz, 1H), 7.58 (s, 1H), 7.36-7.31 (m, 4H),
6.44 (t, J = 4.0 Hz, 1H), 5.67-5.46 (m, 2H), 4.06-4.00 (m,
2H), 3.39-3.32 (m, 2H), 1.71 (br, 1H); 13C{1H} NMR (100
MHz, CDCl3): Major isomer : δ 139.77, 136.04, 130.82,
130.74, 130.53, 130.25, 129.74, 128.89, 127.28, 126.75,
106.40, 63.49, 34.48; Minor isomer : δ 139.54, 136.64,
130.41, 129.10, 127.18, 126.81, 106.54, 58.17, 29.56; Four
peaks are missing due to overlap; HRMS (ESI-TOF) m/z:
[M + H]+ Calcd for C13H15N2O: 215.1179; found: 215.1177.
1
158.76 (C-F, JC-F = 239.0 Hz), 146.94, 138.38, 138.21,
135.52, 131.81, 130.75, 128.66, 128.19, 127.47, 124.90 (C-
3
3
F, JC-F = 8.0 Hz), 121.31, 120.02 (C-F, JC-F = 6.0 Hz),
118.63 (C-F, 2JC-F = 29.0 Hz), 102.75 (C-F, 2JC-F = 29.0 Hz),
63.16, 34.15; Minor isomer : δ 138.43, 137.99, 135.68,
3
132.25, 130.52, 128.96, 128.74, 127.39, 125.07 (C-F, JC-F
3
= 7.0 Hz), 121.50, 121.43, 121.36, 120.02 (C-F, JC-F
=
2
Typical Experimental Procedure for the Synthesized
Compounds (5a-5q): A mixture of 2-(p-tolyl)-2H-indazole
(0.2 mmol, 41.6 mg) (1b), Mn2(CO)10 (5 mol%, 3.8 mg),
and NaOAc (20 mol%, 3.2 mg) was taken in an oven dried
screw-capped reaction tube. Then the reaction vessel was
evacuated and filled with nitrogen for three times. After
that, diallyl carbonate (4) (0.3 mmol) and 1,4-dioxane (1.5
mL) were added, and the resultant mixture was stirred at
100 °C in oil bath for 24 h. After completion of the reaction
(TLC), the reaction was cooled to room temperature and
extracted with ethyl acetate. The organic phase was dried
over anhydrous Na2SO4. The crude residue was obtained
after evaporating the solvent in vacuum and was purified
by column chromatography on silica gel using a mixture of
petroleum ether and ethyl acetate (95:5) as an eluting
solvent to afford the pure product 5b (43.6 mg, 88%) as a
yellow gummy mass.
14.0 Hz), 118.79 (C-F, JC-F = 28.0 Hz), 102.86, 58.11,
29.31; One peak is missing due to C-F coupling and
overlap; Anal. Calcd for C17H14ClFN2O: C, 64.46; H, 4.46;
N, 8.84%; Found: C, 64.65; H, 4.43; N, 8.78%.
4-(2-(5-Chloro-2H-indazol-2-yl)phenyl)but-2-en-1-ol
(3k): Colorless gummy mass (63%, 37.5 mg); Rf = 0.50
1
(PE / EA = 70 : 30); H NMR (400 MHz, CDCl3): δ 8.03,
7.74-7.70 (m, 2H), 7.46-7.34 (m, 4H), 7.28-7.27 (m, 1H),
5.66-5.37 (m, 2H), 3.97-3.93 (m, 2H), 3.35-3.28 (m, 2H),
2.05 (br, 1H); 13C{1H} NMR (100 MHz, CDCl3): Major
isomer : δ 147.66, 139.74, 136.05, 131.05, 130.90, 130.60,
129.85, 129.68, 128.13, 127.36, 126.95, 124.46, 122.37,
119.48, 119.09, 63.24, 34.28; Minor isomer : δ 147.76,
139.55, 136.54, 132.23, 130.08, 130.00, 129.61, 128.29,
128.03, 127.27, 124.62, 119.43, 58.11, 29.43; Three peaks
are missing due to overlap; Anal. Calcd for C17H15ClN2O:
C, 68.34; H, 5.06; N, 9.38%; Found: C, 68.17; H, 5.04; N,
9.50%.
2-(2-Allylphenyl)-2H-indazole (5a): Yellow gummy mass
1
(90%, 42 mg); Rf = 0.50 (PE / EA = 95 : 5); H NMR (400
MHz, CDCl3): δ 8.12 (s, 1H), 7.81 (d, J = 8.4 Hz, 1H), 7.74
(d, J = 8.8 Hz, 1H), 7.48-7.44 (m, 2H), 7.41-7.33 (m, 3H),
7.17-7.13 (m, 1H), 5.90-5.76 (m, 1H), 5.02-5.00 (m, 1H),
4.93-4.88 (m, 1H), 3.32 (d, J = 6.4 Hz, 2H); 13C{1H} NMR
(100 MHz, CDCl3): δ 149.3, 140.0, 136.4, 135.8, 130.7,
129.4, 127.1, 127.0, 126.5, 124.7, 122.2, 121.9, 120.4,
117.9, 116.6, 35.4; Anal. Calcd for C16H14N2: C, 82.02; H,
6.02; N, 11.96%; Found: C, 82.14; H, 5.98; N, 11.88%.
4-(2-(5-Chloro-2H-indazol-2-yl)-5-methylphenyl)but-2-
en-1-ol (3l): Colorless gummy mass (79%, 49 mg); Rf =
1
0.45 (PE / EA = 75 : 25); H NMR (400 MHz, CDCl3): δ
7.79-7.78 (m, 1H), 7.51-7.46 (m, 2H), 7.05-7.02 (m, 2H),
6.94 (t, J = 10.4 Hz, 2H), 5.42-5.12 (m, 2H), 3.73-3.70 (m,
2H), 3.07-3.00 (m, 2H), 2.18 (s, 3H), 1.59 (br, 1H);
13C{1H} NMR (100 MHz, CDCl3): Major isomer : δ
147.55, 139.93, 137.32, 135.64, 131.37, 130.90, 129.79,
127.97, 127.93, 127.88, 126.70, 124.51, 122.31, 119.43,
119.05, 63.23, 34.25, 21.34; Minor isomer : δ 147.66,
140.09, 136.14, 131.09, 129.94, 129.74, 128.13, 127.84,
124.67, 119.37, 58.04, 29.33; Six peaks are missing due to
overlap; Anal. Calcd for C18H17ClN2O: C, 69.12; H, 5.48;
N, 8.96%; Found: C, 69.25; H, 5.51; N, 9.03%.
2-(2-Allyl-4-methylphenyl)-2H-indazole (5b): Yellow
gummy mass (88%, 43.6 mg); Rf = 0.50 (PE / EA = 95 : 5);
1H NMR (400 MHz, CDCl3): δ 8.07 (s, 1H), 7.80-7.78 (m,
1H), 7.72 (d, J = 8.4 Hz, 1H), 7.35-7.31 (m, 2H), 7.19-7.15
(m, 1H), 7.13-7.11 (m, 2H), 5.88-5.80 (m, 1H), 5.01-4.98
(m, 1H), 4.93-4.88 (m, 1H), 3.27 (d, J = 6.4 Hz, 2H), 2.42
(s, 3H); 13C{1H} NMR (100 MHz, CDCl3): δ 149.3, 139.5,
137.7, 136.6, 135.5, 131.2, 127.7, 126.8, 126.4, 124.8,
122.1, 121.9, 120.4, 117.9, 116.4, 35.4, 21.3; HRMS (ESI-
TOF) m/z: [M + H]+ Calcd for C17H17N2: 249.1386; found:
249.1381.
4-(2-(5-Chloro-2H-indazol-2-yl)-5-methoxyphenyl)but-
2-en-1-ol (3m): Yellow gummy mass (80%, 52.5 mg); Rf =
1
0.50 (PE / EA = 60 : 40); H NMR (400 MHz, CDCl3): δ
7.99 (s, 1H), 7.73-7.68 (m, 2H), 7.33-7.25 (m, 2H), 6.90-
6.84 (m, 2H), 5.65-5.37 (m, 2H), 3.95 (d, J = 5.2 Hz, 2H),
3.86 (s, 3H), 3.29-3.23 (m, 2H), 1.81 (br, 1H); 13C{1H}
NMR (100 MHz, CDCl3): Major isomer : δ 160.42, 147.45,
137.65, 132.93, 131.19, 129.50, 128.20, 128.14, 128.07,
124.76, 122.30, 119.40, 119.05, 116.03, 112.11, 63.27,
55.73, 34.49; Minor isomer : δ 130.25, 127.97, 124.90,
2-(2-Allyl-4-methoxyphenyl)-2H-indazole (5c): Yellow
gummy mass (83%, 43.8 mg); Rf = 0.50 (PE / EA = 90 :
10); 1H NMR (400 MHz, CDCl3): δ 8.05 (s, 1H), 7.78 (d, J
= 8.8 Hz, 1H), 7.72 (d, J = 8.4 Hz, 1H), 7.37-7.31 (m, 2H),
7.13 (t, J = 7.6 Hz, 1H), 6.89-6.85 (m, 2H), 5.87-5.77 (m,
This article is protected by copyright. All rights reserved.

10.1002/adsc.202100627
Advanced Synthesis & Catalysis
1H), 5.01 (d, J = 10.0 Hz, 1H), 4.92 (d, J = 17.2 Hz, 1H), 124.4, 122.3, 119.5, 119.1, 116.7, 35.5; Anal. Calcd for
3.86 (s, 3H), 3.24 (d, J = 6.0 Hz, 2H); 13C{1H} NMR (100 C16H13ClN2: C, 71.51; H, 4.88; N, 10.42%; Found: C,
MHz, CDCl3): δ 160.1, 149.2, 137.5, 136.2, 133.3, 128.1, 71.36; H, 4.86; N, 10.53%.
126.4, 125.0, 122.1, 121.9, 120.3, 117.9, 116.8, 115.5,
112.1, 55.6, 35.6; HRMS (ESI-TOF) m/z: [M + H]+ Calcd
2-(2-Allyl-4-methylphenyl)-5-methoxy-2H-indazole
for C17H17N2O: 265.1335; found: 265.1332.
(5n): Colorless gummy mass (41%, 22.7 mg); Rf = 0.50
(PE / EA = 90 : 10); 1H NMR (400 MHz, CDCl3): δ 7.93 (s,
2-(2-Allyl-4-fluorophenyl)-2H-indazole (5d): Colorless 1H), 7.67 (d, J = 9.6 Hz, 1H), 7.31 (d, J = 7.6 Hz, 1H), 7.16
gummy mass (40%, 20 mg); Rf = 0.50 (PE / EA = 95 : 5); (t, J = 8.0 Hz, 2H), 7.05-7.02 (m, 1H), 6.92 (d, J = 2.0 Hz,
1H NMR (400 MHz, CDCl3): δ 8.07 (s, 1H), 7.79-7.7.76 (m, 1H), 5.88-5.78 (m, 1H), 5.01-4.98 (m, 1H), 4.93-4.88 (m,
1H), 7.72 (d, J = 8.4 Hz, 1H), 7.43-7.40 (m, 1H), 7.37-7.33 1H), 3.86 (s, 3H), 3.27 (d, J = 6.4 Hz, 2H), 2.41 (s, 3H);
(m, 1H), 7.17-7.14 (m, 1H), 7.13-7.11 (m, 1H), 7.09-7.07 13C{1H} NMR (100 MHz, CDCl3): δ 155.4, 146.2, 139.3,
(m, 1H), 7.06-7.03 (m, 1H), 5.86-5.76 (m, 1H), 5.07-5.04 137.8, 136.7, 135.5, 131.2, 127.7, 126.7, 123.8, 121.9,
(m, 1H), 4.96-4.92 (m, 1H), 3.26 (d, J = 6.4 Hz, 2H); 121.4, 119.4, 116.4, 96.4, 55.5, 35.5, 21.3; Anal. Calcd for
13C{1H} NMR (100 MHz, CDCl3): δ 162.9 (C-F, JC-F
=
C18H18N2O: C, 77.67; H, 6.52; N, 10.06%; Found: C,
1
248.0 Hz), 135.5, 128.8 (C-F, 3JC-F = 10.0 Hz), 127.1, 126.7, 77.85; H, 6.56; N, 10.11%.
125.0, 124.9, 122.4, 120.4, 118.0, 117.5, 117.4, 117.2 (C-F,
2
2JC-F = 22.0 Hz), 114.0 (C-F, JC-F = 22.0 Hz), 35.4; Anal.
Calcd for C16H13FN2: C, 76.17; H, 5.19; N, 11.10%; Found:
C, 76.33; H, 5.21; N, 11.19%.
1-(2-Allylphenyl)-1H-pyrazole (5o):[11c] Yellow gummy
1
mass (72%, 26.5 mg); Rf = 0.50 (PE / EA = 95 : 5); H
NMR (400 MHz, CDCl3): δ 7.72 (d, J = 1.6 Hz, 1H), 7.60
(d, J = 2.0 Hz, 1H), 7.38-7.30 (m, 4H), 6.42 (d, J = 2.0 Hz,
2-(2-Allyl-4-chlorophenyl)-2H-indazole (5e): Colorless 1H), 5.89-5.79 (m, 1H), 5.03-4.95 (m, 1H), 4.94-4.90 (m,
gummy mass (46%, 24.6 mg); Rf = 0.50 (PE / EA = 92 : 8); 1H), 3.33 (d, J = 6.4 Hz, 2H); 13C{1H} NMR (100 MHz,
1H NMR (400 MHz, CDCl3): δ 8.08 (s, 1H), 7.78-7.76 (m, CDCl3): δ 140.4, 139.8, 136.6, 135.8, 130.9, 130.7, 128.7,
1H), 7.72 (d, J = 8.4 Hz, 1H), 7.40-7.38 (m, 2H), 7.36-7.33 127.1, 126.6, 116.3, 106.3, 35.6; Anal. Calcd for C12H12N2:
(m, 2H), 7.16-7.12 (m, 1H), 5.86-5.76 (m, 1H), 5.06-5.04 C, 78.23; H, 6.57; N, 15.21%; Found: C, 78.39; H, 6.53; N,
(m, 1H), 4.96-4.91 (m, 1H), 3.29 (d, J = 7.6 Hz, 2H); 15.09%.
13C{1H} NMR (100 MHz, CDCl3): δ 149.5, 135.5, 130.6,
1-(2-Allyl-4-fluorophenyl)-1H-pyrazole (5o'):[11c] Yellow
gummy mass (77%, 31 mg); Rf = 0.50 (PE / EA = 95 : 5);
1H NMR (400 MHz, CDCl3): δ 7.71 (d, J = 1.6 Hz, 1H),
7.56 (d, J = 2.4 Hz, 1H), 7.32-7.28 (m, 1H), 7.05-6.97 (m,
2H), 6.42 (t, J = 2.4 Hz, 1H), 5.58-5.75 (m, 1H), 5.07-5.04
129.8, 128.2, 127.2, 126.8, 124.8, 122.9, 122.8, 122.5,
120.5, 120.4, 117.9, 117.5, 35.3; Anal. Calcd for
C16H13ClN2: C, 71.51; H, 4.88; N, 10.42%; Found: C,
71.66; H, 4.84; N, 10.31%.
2-(2-Allyl-4-bromophenyl)-2H-indazole (5f): Colorless (m, 1H), 4.98-4.93 (m, 1H), 3.26 (d, J = 6.4 Hz, 2H);
gummy mass (50%, 31 mg); Rf = 0.45 (PE / EA = 95 : 5); 13C{1H} NMR (100 MHz, CDCl3): δ 162.4 (C-F, JC-F
=
1
1H NMR (400 MHz, CDCl3): δ 8.08 (s, 1H), 7.79-7.76 (m, 247.0 Hz), 140.6, 138.7 (C-F, JC-F = 8.0 Hz), 135.8 (C-F,
3
1H), 7.72 (d, J = 8.4 Hz, 1H), 7.54 (d, J = 2.0 Hz, 1H), 2JC-F = 25.0 Hz), 131.1, 128.4 (C-F, JC-F = 9.0 Hz), 117.2,
3
2
7.51-7.49 (m, 1H), 7.36-7.31 (m, 2H), 7.16-7.12 (m, 1H), 117.1, 117.0, 113.9 (C-F, JC-F = 23.0 Hz), 106.4, 35.5;
5.86-5.76 (m, 1H), 5.06-5.04 (m, 1H), 4.96-4.91 (m, 1H), Anal. Calcd for C12H11FN2: C, 71.27; H, 5.48; N, 13.85%;
3.28 (d, J = 6.4 Hz, 2H); 13C{1H} NMR (100 MHz, Found: C, 71.07; H, 5.46; N, 13.93%.
CDCl3): δ 149.6, 139.1, 138.1, 135.5, 133.6, 130.3, 128.5,
126.8, 124.7, 123.4, 122.5, 122.1, 120.4, 118.0, 117.4,
2-(2-Allylphenyl)-4,5-dihydrooxazole (5p): Colorless
35.3; Anal. Calcd for C16H13BrN2: C, 61.36; H, 4.18; N,
gummy mass (66%, 24.6 mg); Rf = 0.50 (PE / EA = 95 : 5);
1H NMR (400 MHz, CDCl3): δ 7.78-7.76 (m, 1H), 7.40-
7.35 (m, 1H), 7.27-7.24 (m, 2H), 6.04-5.94 (m, 1H), 5.05-
8.94%; Found: C, 61.58; H, 4.21; N, 9.01%.
2-(2-Allylphenyl)-5-fluoro-2H-indazole (5h): Yellow 5.04 (m, 1H), 5.02-4.97 (m, 1H), 4.38 (t, J = 9.6 Hz, 2H),
gummy mass (82%, 41 mg); Rf = 0.50 (PE / EA = 93 : 7); 4.07 (t, J = 9.6 Hz, 2H), 3.78 (d, J = 6.8 Hz, 2H); 13C{1H}
1H NMR (400 MHz, CDCl3): δ 8.06 (s, 1H), 7.78-7.74 (m, NMR (100 MHz, CDCl3): δ 165.0, 140.4, 137.6, 130.8,
1H), 7.48-7.35 (m, 4H), 7.31-7.28 (m, 1H), 7.17-7.12 (m, 130.4, 130.1, 127.2, 126.1, 115.6, 67.0, 55.4, 38.4; Anal.
1H), 5.88-5.78 (m, 1H), 5.01-4.98 (m, 1H), 4.91-4.86 (m, Calcd for C12H13NO: C, 76.98; H, 7.00; N, 7.48%; Found:
1H), 3.30 (d, J = 6.4 Hz, 2H); 13C{1H} NMR (100 MHz, C, 77.21; H, 7.03; N, 7.54%.
1
CDCl3): δ 158.6 (C-F, JC-F = 241.0 Hz), 146.8, 139.9,
136.3, 135.8, 130.8, 129.6, 127.2, 126.9, 124.9 (C-F, 3JC-F
=
2-(2-Allylphenyl)pyridine (5q):[11b] Yellow gummy mass
3
1
8.0 Hz), 121.3, 121.1, 120.0 (C-F, JC-F = 10.0 Hz), 118.2
(73%, 28.5 mg); Rf = 0.50 (PE / EA = 95 : 5); H NMR
2
2
(C-F, JC-F = 29.0 Hz), 116.6, 102.7 (C-F, JC-F = 25.0 Hz),
35.5; Anal. Calcd for C16H13FN2: C, 76.17; H, 5.19; N,
11.10%; Found: C, 76.04; H, 5.15; N, 11.02%.
(400 MHz, CDCl3): δ 8.58 (d, J = 4.8 Hz, 1H), 7.63-7.59
(m, 1H), 7.30-7.13 (m, 6H), 5.83-5.64 (m, 1H), 4.87-4.76
(m, 2H), 3.40 (d, J = 6.4 Hz, 2H);13C{1H} NMR (100 MHz,
CDCl3): δ 159.7, 149.1, 140.3, 137.5, 136.1, 130.0, 129.8,
2-(2-Allyl-4-methylphenyl)-5-fluoro-2H-indazole
(5i): 128.4, 126.3, 125.1, 124.1, 121.7, 115.6, 37.4; Anal. Calcd
Yellow gummy mass (56%, 29.8 mg); Rf = 0.50 (PE / EA = for C14H13N: C, 86.12; H, 6.71; N, 7.17%; Found: C, 85.98;
1
95 : 5); H NMR (400 MHz, CDCl3): δ 8.03 (s, 1H), 7.71- H, 6.75; N, 7.27%.
7.73 (m, 1H), 7.31-7.27 (m, 2H), 7.18-7.10 (m, 3H), 5.86-
5.76 (m, 1H), 5.00-4.97 (m, 1H), 4.91-4.86 (m, 1H), 3.25
(d, J = 6.8 Hz, 2H), 2.42 (s, 3H); 13C{1H} NMR (100 MHz,
Acknowledgments
1
CDCl3): δ 158.6 (C-F, JC-F = 238.0 Hz), 146.7, 139.6,
3
137.5, 136.5, 135.4, 131.3, 126.6, 124.9 (C-F, JC-F = 8.0
A.H. acknowledges the financial support from SERB, New Delhi
(Grant No. CRG/2020/000362). A. K. G and K. K. D thank CSIR
for their fellowship.
3
2
Hz), 120.0 (C-F, JC-F = 9.0 Hz), 118.0 (C-F, JC-F = 28.0
2
Hz), 116.5, 102.7 (C-F, JC-F = 24.0 Hz), 35.4, 21.3; Anal.
Calcd for C17H15FN2: C, 76.67; H, 5.68; N, 10.52%; Found:
C, 76.88; H, 5.71; N, 10.59%.
2-(2-Allylphenyl)-5-chloro-2H-indazole (5k): Yellow
gummy mass (61%, 32.7 mg); Rf = 0.50 (PE / EA = 95 : 5);
1H NMR (400 MHz, CDCl3): δ 8.05 (s, 1H), 7.74-7.70 (m,
2H), 7.48-7.35 (m, 5H), 7.28-7.25 (m, 1H), 5.87-5.77 (m,
1H), 5.00-4.98 (m, 1H), 4.89-4.85 (m, 1H), 3.28 (d, J = 6.4
Hz, 2H);13C{1H} NMR (100 MHz, CDCl3): δ 147.7, 139.8,
136.2, 135.8, 130.8, 129.7, 128.0, 127.9, 127.2, 126.9,
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UPDATE
ortho-Allylation of 2-Arylindazoles with Vinyl
Cyclic Carbonate and Diallyl Carbonate via
Manganese-Catalyzed CH Bond Activation
Adv. Synth. Catal. Year, Volume, Page – Page
Asim Kumar Ghosh, Krishna Kanta Das, and
Alakananda Hajra*
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