A Cascade Synthesis of Hetero-arylated Triarylmethanes Through a Double 5-endo-dig Cyclization Sequence

Article abstract of DOI:10.1002/asia.201900960

A sequential two-step method for the synthesis of hetero-arylated triarylmethanes through a Ag-catalyzed sequential double cyclization–nucleophilic addition cascade is described. This methodology basically involves an initial 5-endo-dig cyclization of o-alkynyl anilines to provide 2-substituted indole derivatives, which then react with 2-(2-enynyl)-pyridines to afford indolizine-containing unsymmetrical triarylmethanes through another 5-endo-dig cyclization.

Full text of DOI:10.1002/asia.201900960

DOI: 10.1002/asia.201900960
Full Paper
A Cascade Synthesis of Hetero-arylated Triarylmethanes Through
a Double 5-endo-dig Cyclization Sequence
Dilip K. Paluru+, Sriram Mahesh+, Feroz Ahmad, and Ramasamy Vijaya Anand*[a]
Abstract: A sequential two-step method for the synthesis of
hetero-arylated triarylmethanes through a Ag-catalyzed se-
quential double cyclization–nucleophilic addition cascade is
described. This methodology basically involves an initial 5-
endo-dig cyclization of o-alkynyl anilines to provide 2-substi-
tuted indole derivatives, which then react with 2-(2-enynyl)-
pyridines to afford indolizine-containing unsymmetrical triar-
ylmethanes through another 5-endo-dig cyclization.
Introduction
volve either a Lewis acid/Brønsted acid mediated Friedel–
Crafts reaction[6] or a transition metal catalyzed cross coupling
reaction of diarylmethanol derivatives with relevant aryl cou-
pling partners.[7] Other miscellaneous processes,[8] including
metal catalyzed direct arylation of diarylmethanes, have also
been reported.[9] Metal catalyzed domino cyclization of o-alkyn-
yl derivatives is one of the prevalent strategies for the synthe-
sis of fused heteroaromatic systems.[10] Especially, domino reac-
tions, involving 5-endo-dig cyclization, have been elaborately
explored for the synthesis of substituted indolizine[11] and
indole derivatives.[12] Recently, a fascinating approach has been
developed to access indolizine containing diaryl- and triarylme-
thane derivatives through a metal catalyzed 5-endo-dig cycliza-
tion of 2-(2-enynyl)pyridines followed by a nucleophilic addi-
tion of a wide range of nucleophiles (a, Scheme 1).[13] Similarly,
metal catalyzed 5-endo-dig cyclization of 2-alkynyl anilines fol-
lowed by trapping with electrophiles has been found to be a
competent way to synthesize 2,3-substituted indoles (b,
Scheme 1).[14] While working on the development of new pro-
tocols to access diaryl- and triarylmethane derivatives from 2-
(2-enynyl)pyridines[15a] and p-quinone methides,[15b–g] we envi-
In recent years, triarylmethanes have gained importance as a
valuable synthetic target due to their widespread applications,
including in material science.[1] Besides, some of the unsym-
metrical triarylmethanes exhibit noteworthy therapeutic activi-
ties.[2] For example, unsymmetrical triarylmethane 1 was found
to possess remarkable anti-breast cancer activity (Figure 1).[3]
Figure 1. Some therapeutically active triarylmethanes.
Similarly, indole based unsymmetrical triarylmethanes, such as
2&3 have shown significant aromatase inhibition activity and
anti-inflammatory activity, respectively.[2,4] Due to the diverse
range of applications and their structural complexity, unsym-
metrical triarylmethanes have drawn attention of academic as
well as industrial chemists to devise innumerable synthetic
ways to access them.[5] The dominant approaches for the syn-
thesis of symmetrical and unsymmetrical triarylmethanes in-
[a] Dr. D. K. Paluru,+ Dr. S. Mahesh,+ F. Ahmad, Dr. R. Vijaya Anand
Department of Chemical Sciences
Indian Institute of Science Education and Research (IISER) Mohali
Sector 81, Knowledge City, S. A. S. Nagar, Manauli (PO), Punjab-140306
(India)
E-mail: rvijayan@iisermohali.ac.in
[+] These authors contributed equally to this work.
Supporting information and the ORCID identification number(s) for the au-
thor(s) of this article can be found under:
https://doi.org/10.1002/asia.201900960.
This manuscript is part of a special issue celebrating the 20th anniversary of
the Chemical Research Society of India (CRSI). A link to the Table of Con-
tents of the special issue will appear here when the complete issue is pub-
lished.
Scheme 1. Approaches toward substituted indole and indolizine derivatives.
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sioned that it could be possible to access unsymmetrical triar-
ylmethanes by combining these two different strategies (a&b,
Scheme 1) through suitable modifications. In line with this con-
cept, we have developed an efficient sequential two-step
method for the synthesis of indolizine-containing unsymmetri-
cal triarylmethanes through a metal catalyzed double 5-endo-
dig cyclization cascade between 2-alkynyl anilines and 2-(2-
enynyl)pyridines (c, Scheme 1), and the results are discussed
herein. Through this cascade, instalment of two new CÀN
bonds and a CÀC bond in the product with 100% atom-econo-
my could be achieved.
mum (90%) in that case (Entry 4). The yield of 7a was lower
when the reaction was conducted in other solvents such as
DMF, MeOH, DCE etc. (Entries 7–10). The reaction also worked
at room temperature (Entry 11); however, it required a very
long time (70 h) for the complete conversion of 4a to 5. In the
absence of silver catalyst, even the formation of 5 was not ob-
served (Entry 12). Similarly, another experiment was carried
out, in which, 5 was refluxed along with 6a in THF without
any catalyst and 7a was detected only in traces even after
24 h (Entry 13). These two experiments clearly indicate that a
catalyst is required to drive both the steps. In addition to that,
another experiment was done, in which 5 was treated with 6a
in the presence of Ag(OCOCF3) catalyst in refluxing THF and, as
expected, 7a was obtained in 93% isolated yield in an hour
(Entry 14). This observation evidently signifies that the reaction
is actually proceeding through indole derivative 5.[17] When a
mixture of 4a and 6a was refluxed together in THF with
Ag(OCOCF3) catalyst, many unidentified products were ob-
served along with traces of expected product 7a (Entry 15).
The generality of this transformation was investigated by
employing a diverse range of substituted o-alkynyl anilines
and 2-(2-enynyl)pyridines under optimized conditions (Entry 4,
Table 1). Table 2 reveals the substrate scope of this protocol
with a variety of substituted 2-(2-enynyl)pyridines. Initially, the
Results and Discussion
The optimization studies were performed using o-alkynyl ani-
line (4a)[16] and 2-(2-enynyl) pyridine (6a)[13a] and the results
are disclosed in Table 1. Since this transformation involves two
steps, 6a was added to the reaction mixture after the com-
plete conversion of 4a to 5 (by TLC). The preliminary experi-
ment was performed using Cu(OTf)2 as a catalyst in refluxing
THF (Entry 1). To our satisfaction, the expected product 7a was
isolated in 25% yield. PdCl2 was found to be efficient for the
formation of 5, but ineffective to drive the second step
(Entry 2). When AgSbF6 was used as a catalyst, 7a was ob-
tained in 45% yield (Entry 3). Though most of the silver salts
are effective to catalyse this transformation (Entries 4–6), Ag(O-
COCF3) was found to be the best as the yield 7a was maxi-
Table 2. Substrate scope with substituted 2-(2-enynyl)pyridines.[a]
Table 1. Optimization studies.[a,b]
Entry
Catalyst
Solvent
T1, T2 [h]
t[c]
Yield of 7a [%][d]
[h]
1
2
3
4
5
6
7[e]
8
Cu(OTf)2
PdCl2
AgSbF6
Ag(OCOCF3)
AgBF4
AgNO3
Ag(OCOCF3)
Ag(OCOCF3)
Ag(OCOCF3)
Ag(OCOCF3)
Ag(OCOCF3)
–
THF
THF
THF
THF
THF
12, 8
5, 48
4, 4
6, 1
4, 4
4, 4
5, 2
5, 5
3, 3
5, 5
70, 2
24, 0
0, 24
0, 1
8
20
53
8
7
8
8
7
10
6
10
72
24
24
1
25
–
45
90
55
70
80
50
60
60
85
–
traces
93
traces
THF
DMF
MeOH
DCE
Toluene
THF
THF
THF
THF
THF
9
10
11[f]
12[g]
13[h]
14[i]
15
–
Ag(OCOCF3)
Ag(OCOCF3)
8
[a] Reaction conditions: All reactions were carried out with 0.1 mmol of
6a in 1.5 mL solvent under reflux conditions. [b] 6a was added to a reac-
tion mixture after complete consumption of 4a. [c] Total time taken for
double cyclization {T1 +T2}. [d] Isolated yield. [e] Reaction temperature:
1008C. [f] Reaction was performed at room temperature (25–278C).
[g] Reaction was performed without any catalyst. [h] Reaction was per-
formed with isolated 5 without catalyst. [i] Reaction was performed with
isolated 5.
[a] Reactions were carried out with 0.1 mmol of 6(b–w) in 1.5 mL of re-
fluxing THF. In all these experiments, 4a was refluxed in THF along with
10 mol% of Ag(OCOCF3) for 6 h before the addition of 6(b–w), and the
reaction was continued for another hour. The newly formed bonds are
represented in bold. Yields reported are isolated yields.
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substrate scope was evaluated with 2-(2-enynyl)pyridines (6b–
i) having different aryl groups at the alkyne part and, in all
those cases, the expected products (7b–i) were obtained in
good to excellent yields (68–97%). 2-(2-enynyl)pyridines (6j–l)
substituted with alicyclic compounds (such as cyclopropyl, cy-
clopentyl and cyclohexyl) were also found to be suitable for
this reaction, and the respective products (7j–l) were obtained
in 56–94% isolated yields under optimized conditions. Then,
we went on to investigate the substrate scope with other 2-(2-
enynyl)pyridines (6m–u) having different aryl substituents
(both electron-rich and electron-poor) at the alkene part. To
our delight, in all those cases, the expected triarylmethanes
(7m–u) were formed in the range of 53–92% yields. In the
case of 6v, which was derived from quinoline-2-carboxylic
acid, the product 7v was obtained in 83% yield. However, the
precursor 6w (prepared from isoquinoline-1-carboxylic acid) af-
forded the product 7w only in 44% yield under the reaction
conditions.
The substrate scope studies were also elaborated to differ-
ent o-alkynyl anilines (4b–j), substituted with a range of aryl or
alkyl groups at the alkyne part, under the optimal conditions
and the results are summarized in Table 3. Most of o-alkynyl
Scheme 2. Plausible Mechanism.
goes proton isomerization to give the indole derivative 5 with
the expulsion of the catalyst (cycle A). In the subsequent step,
activation of the alkyne part of 6a by silver catalyst followed
by 5-endo-dig cyclization leads to indolizinium salt IV, in which
the exocyclic alkene part becomes relatively more electrophilic
due to the presence of the positive charge on nitrogen
(cycle B). Remote nucleophilic addition of 5 to the exocyclic
olefinic center of IV generates another intermediate V, which
then undergoes aromatization followed by proton transfer to
afford 7a along with the regeneration of silver catalyst.
Table 3. Substrate scope with different o-alkynyl anilines.[a]
Conclusions
In conclusion, we have demonstrated an atom-efficient se-
quential two-step protocol for the synthesis of hetero-arylated
unsymmetrical triarylmethanes through
a silver-catalyzed
double 5-endo-dig cyclization cascade. The generality of this
transformation was examined using a wide range of o-alkynyl
anilines and 2-(2-enynyl)pyridines. We believe that this meth-
odology will find some interest to organic as well as medicinal
chemists, as similar types of heteroarylated triarylmethane de-
rivatives are found to possess valuable medicinal properties.
[a] All reactions were carried out with 0.1 mmol of 6a in 1.5 mL THF. The
newly formed bonds are represented in bold. Yields reported are isolated
yields.
Experimental Section
anilines, tethered with electron-rich or electron-poor aryl sub-
stituents (4b–h), underwent a smooth conversion to their cor-
responding triarylmethane derivatives (8b–h) in the range of
42–90% yields. In case of 4i (having cyclopropane at the
alkyne part), the desired product 8i was obtained in 50%
yield. Another o-alkynyl aniline 4j, derived from 6-chloroaniline
derivative, gave the corresponding product 8j in 70% yield.
A plausible mechanism for this sequential two-step transfor-
mation has been proposed (Scheme 2). In the initial step, silver
catalyst activates the alkyne part of 4a, and a successive 5-
endo-dig cyclization leads to intermediate II, which then under-
General methods: Most of the reagents and starting materials
used were purchased from commercial sources and are used as
such. All the 2-(2-enynyl) pyridines[13a] and o-alkynyl anilines[15b,16]
were prepared by following a known literature procedure. Melting
points were measured for the solids resulted from the evaporation
of the eluents. Melting points were recorded on SMP20 melting
point apparatus and are uncorrected. 1H, 13C and 19F spectrum
were recorded in CDCl3 (400, 100 and 376 MHz, respectively) on
Bruker FT-NMR spectrometer. Chemical shift (d) values are reported
in parts per million relative to TMS (for 1H and 13C) and BF3.Et2O
(for 19F) and the coupling constants (J) are reported in Hz. High res-
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olution mass spectra were recorded on Waters Q-TOF Premier-
HAB213 spectrometer. FT-IR spectra were recorded on a PerkinElm-
er FT-IR spectrometer. Thin layer chromatography was performed
on Merck silica gel 60 F254 TLC plates using EtOAc/Hexane as an
eluent. Column chromatography was carried out through silica gel
(100–200 mesh) using ethyl acetate/hexane mixture as an eluent.
6.94–6.90 (m, 1H), 6.73 (s, 1H), 6.49–6.45 (m, 1H), 6.42–6.38 (m,
1H), 6.11 (s, 1H), 2.39 ppm (s, 3H); 13C NMR (100 MHz, CDCl3): d=
144.7, 136.6, 136.4, 135.2, 133.2, 130.7, 129.8, 129.6, 128.83, 128.83,
128.7, 128.5, 128.1, 127.9 (2C), 125.9, 124.4, 122.3, 121.9, 121.8,
119.5, 118.1, 116.2, 116.17, 115.8, 115.4, 110.8, 110.4, 39.3, 21.4 ppm;
HRMS (ESI): m/z calcd for C36H29N2 [M+H]+: 489.2331; found:
489.2313.
General procedure for the Ag-catalyzed synthesis of triarylme-
thanes: Ag(OCOCF3) (0.01 mmol) was added to a solution of o-al-
kynyl aniline (0.11 mmol) in THF (1.5 mL) and the resultant mixture
was refluxed until the complete consumption of o-alkynyl aniline
(by TLC). 2-(2-Enynyl) pyridine (0.1 mmol) was then added to the
reaction mixture and stirring was continued under reflux condition
until 2-(2-enynyl)pyridine was completely consumed (by TLC). The
solvent was removed under reduced pressure and the residue was
directly loaded on a silica gel column and purified using 10–20%
ethyl acetate/hexane mixture as an eluent to get the pure triaryl-
methanes.
[3-((3-(4-Phenoxyphenyl)indolizin-1-yl)(phenyl)methyl)]-2-
phenyl-1H-indole (7e): Off white solid; yield 90% (51 mg); Rf =0.5
(20% EtOAc in hexane); M.P. 118–1208C; FT-IR: n˜ =3058, 1489,
1237, 743, 699 cmÀ1 1H NMR (400 MHz, CDCl3): d=8.21 (d, J=
;
7.1 Hz, 1H), 8.07 (s, 1H), 7.52–7.30 (m, 13H), 7.27–7.23 (m, 2H),
7.21–7.17 (m, 1H), 7.15–7.11 (m, 2H), 7.06 (d, J=8.6 Hz, 4H), 6.98
(d, J=8.9 Hz, 1H), 6.93 (t, J=7.3 Hz, 1H), 6.73 (s, 1H), 6.51–6.47 (m,
1H), 6.44–6.41 (m, 1H), 6.12 ppm (s, 1H); 13C NMR (100 MHz,
CDCl3): d=157.2, 156.2, 144.7, 136.4, 135.2, 133.2, 130.7, 129.9,
129.5, 128.84, 128.83, 128.7, 128.5, 128.2, 127.9, 127.8, 125.9, 123.8,
123.5, 122.2, 122.0, 121.7, 119.6, 119.3, 119.0, 118.1, 116.3, 116.2,
116.0, 115.5, 110.9, 110.6, 39.3 ppm; HRMS (ESI): m/z calcd for
C41H31N2O [M+H]+: 567.2437; found: 567.2412.
2-Phenyl-[3-(phenyl(3-phenylindolizin-1-yl)methyl)]-1H-indole
(7a): Light yellow solid; yield 90% (42.7 mg); Rf =0.5 (20% EtOAc
in hexane); M.P. 86–898C; FT-IR: n˜ =3054, 1449, 1301, 742,
698 cmÀ1
;
1H NMR (400 MHz, CDCl3): d=8.27 (d, J=7.1 Hz, 1H),
[3-((3-(4-Methoxy-2-methylphenyl)indolizin-1-yl)(phenyl)meth-
yl)]-2-phenyl-1H-indole (7 f): Light brown solid; yield 75%
(39 mg); Rf =0.6 (20% EtOAc in hexane); M.P. 115–1178C; FT-IR: n˜ =
8.07 (s, 1H), 7.53–7.50 (m, 4H), 7.44–7.35 (m, 6H), 7.32–7.30 (m,
3H), 7.27–7.23 (m, 3H), 7.20–7.17 (m, 1H), 7.15–7.11 (m, 1H), 6.97
(d, J=9.0 Hz, 1H), 6.92 (t, J=7.9 Hz, 1H), 6.75 (s, 1H), 6.51–6.47 (m,
1H), 6.42 (t, J=7.0 Hz, 1H), 6.11 ppm (s, 1H); 13C NMR (100 MHz,
CDCl3): d=144.7, 136.4, 135.2, 133.2, 132.7, 130.9, 128.9, 128.8 (2C),
128.7, 128.5, 128.2, 127.9, 126.8, 125.9, 124.4, 122.3, 122.0, 121.8,
119.6, 118.2, 116.4, 116.2, 116.1, 115.7, 115.67, 110.8, 110.6,
39.3 ppm; HRMS (ESI): m/z calcd for C35H27N2 [M+H]+: 475.2175;
found: 475.2153.
1
2929, 1457, 1306, 742, 701 cmÀ1; H NMR (400 MHz, CDCl3): d=8.08
(s, 1H), 7.55–7.53 (m, 2H), 7.49 (d, J=7.1 Hz, 1H), 7.46–7.42 (m,
2H), 7.40–7.30 (m, 4H), 7.28–7.22 (m, 4H), 7.20–7.17 (m, 1H), 7.13–
7.09 (m, 1H), 6.95 (d, J=9.0 Hz, 1H), 6.90–6.86 (m, 2H), 6.79 (dd,
J=8.4, 2.6 Hz, 1H), 6.60 (s, 1H), 6.47–6.43 (m, 1H), 6.37–6.33 (m,
1H), 6.14 (s, 1H), 3.84 (s, 3H), 2.10 ppm (s, 3H); 13C NMR (100 MHz,
CDCl3): d=159.5, 145.0, 140.0, 136.4, 135.0, 133.3, 132.5, 129.4,
128.9, 128.86, 128.7, 128.6, 128.1, 127.9, 125.9, 124.4, 123.0, 122.6,
121.9, 121.8, 119.4, 117.8, 116.4, 115.9, 115.8, 115.3, 115.29, 111.3,
110.8, 109.9, 55.4, 39.4, 20.2 ppm; HRMS (ESI): m/z calcd for
C37H31N2O [M+H]+: 519.2437; found: 519.2417.
[3-((3-(4-(tertButyl)phenyl)indolizin-1-yl)(phenyl)methyl)]-2-
phenyl-1H-indole (7b): Off white solid; yield 93% (49.3 mg); Rf =
˜
0.7 (20% EtOAc in hexane); M.P. 140–1428C; FT-IR: N=2962, 1457,
1267, 741, 699 cmÀ1 1H NMR (400 MHz, CDCl3): d=8.28 (d, J=
;
7.1 Hz, 1H), 8.06 (s, 1H), 7.53–7.51 (m, 2H), 7.49–7.31 (m, 11H),
7.27–7.23 (m, 2H), 7.21–7.17 (m, 1H), 7.13 (t, J=7.7 Hz, 1H), 6.98
(d, J=8.9 Hz, 1H), 6.92 (t, J=7.7 Hz, 1H), 6.75 (s, 1H), 6.50–6.46 (m,
1H), 6.43–6.39 (m, 1H), 6.12 (s, 1H), 1.37 ppm (s, 9H); 13C NMR
(100 MHz, CDCl3): d=149.9, 144.7, 136.4, 135.1, 133.3, 130.7, 129.9,
128.9 (2C), 128.7, 128.5, 128.1, 127.9, 127.6, 125.9, 125.8, 124.3,
122.5, 122.0, 121.8, 119.6, 118.1, 116.3, 116.2, 115.9, 115.6, 110.8,
110.4, 39.3, 34.7, 31.5 ppm; HRMS (ESI): m/z calcd for C39H35N2
[M+H]+: 531.2801; found: 531.2778.
[3-((3-(2-Chlorophenyl)indolizin-1-yl)(phenyl)methyl)]-2-phenyl-
1H-indole (7g): Off white solid; yield 74% (37.6 mg); Rf =0.5 (20%
EtOAc in hexane); M.P. 98–1008C; FT-IR: n˜ =2929, 1457, 1308, 743,
701 cmÀ1 1H NMR (400 MHz, CDCl3): d=8.08 (s, 1H), 7.60 (d, J=
;
7.0 Hz, 1H), 7.54–7.49 (m, 3H), 7.45–7.37 (m, 4H), 7.36–7.24 (m,
8H), 7.21–7.17 (m, 1H), 7.14–7.10 (m, 1H), 6.98 (d, J=9.0 Hz, 1H),
6.90 (t, J=7.4 Hz, 1H), 6.73 (s, 1H), 6.54–6.50 (m, 1H), 6.45–6.41 (m,
1H), 6.14 ppm (s, 1H); 13C NMR (100 MHz, CDCl3): d=144.8, 136.4,
135.1, 134.7, 133.3, 133.0, 131.6, 130.4, 130.0, 129.1, 128.9, 128.89,
128.7, 128.6, 128.2, 128.0, 126.9, 125.9, 123.3, 122.0, 121.9, 121.2,
119.6, 117.8, 116.8, 116.3, 116.2, 115.8, 110.8, 110.1, 39.5 ppm; HRMS
(ESI): m/z calcd for C35H26ClN2 [M+H]+: 509.1785; found: 509.1768.
[3-((3-(4-Pentylphenyl)indolizin-1-yl)(phenyl)methyl)]-2-phenyl-
1H-indole (7c) : Green solid; yield 68% (37 mg); Rf =0.6 (20%
EtOAc in hexane); M.P. 130–1328C; FT-IR: n˜ =2928, 1457, 1304, 741,
700 cmÀ1
;
1H NMR (400 MHz, CDCl3): d=8.27 (d, J=7.1 Hz, 1H),
[3-((3-(6-Methoxynaphthalen-2-yl)indolizin-1-yl)(phenyl)methyl)]-
2-phenyl-1H-indole (7h) : Light yellow solid; yield 85% (47.1 mg);
Rf =0.5 (20% EtOAc in hexane); M.P. 98–1008C; FT-IR: n˜ =2929,
8.06 (s, 1H), 7.54–7.52 (m, 2H), 7.46–7.32 (m, 10H), 7.28–7.24 (m,
3H), 7.22–7.18 (m, 1H), 7.14 (t, J=7.9 Hz, 1H), 6.99 (d, J=8.9 Hz,
1H), 6.95–6.92 (m, 1H), 6.75 (s, 1H), 6.50–6.47 (m, 1H), 6.43–6.40
(m, 1H), 6.13 (s, 1H), 2.65 (t, J=7.6 Hz, 2H), 1.67 (quintet, J=
7.4 Hz, 2H), 1.41–1.36 (m, 4H), 0.94 ppm (t, J=6.7 Hz, 3H);
13C NMR (100 MHz, CDCl3): d=144.7, 141.7, 136.4, 135.2, 133.2,
130.7, 130.0, 128.9, 128.84, 128.82, 128.7, 128.5, 128.1, 127.9 (2C),
125.9, 124.5, 122.4, 121.9, 121.8, 119.6, 118.1, 116.2, 116.19, 115.8,
115.5, 110.8, 110.4, 39.3, 35.8, 31.6, 31.3, 22.7, 14.2 ppm; HRMS
(ESI): m/z calcd for C40H37N2 [M+H]+: 545.2957; found: 545.2934.
1449, 1218, 741, 701 cmÀ1 1H NMR (400 MHz, CDCl3): d=8.34 (d,
;
J=7.0 Hz, 1H), 8.09 (s, 1H), 7.90 (s, 1H), 7.77 (d, J=8.6 Hz, 1H),
7.72 (d, J=8.7 Hz, 1H), 7.60 (dd, J=8.5, 1.5 Hz, 1H), 7.54–7.52 (m,
2H), 7.44–7.32 (m, 7H), 7.28–7.24 (m, 2H), 7.21–7.12 (m, 4H), 7.00
(d, J=8.9 Hz, 1H), 6.93 (t, J=7.6 Hz, 1H), 6.83 (s, 1H), 6.52–6.49 (m,
1H), 6.46–6.42 (m, 1H), 6.14 (s, 1H), 3.94 ppm (s, 3H); 13C NMR
(100 MHz, CDCl3): d=157.8, 144.7, 136.4, 135.2, 133.5, 133.2, 131.0,
129.5, 129.3, 128.9 (2C), 128.7, 128.6, 128.2, 128.0, 127.9, 127.3,
127.1, 126.0, 125.9, 124.5, 122.3, 122.0, 121.8, 119.6, 119.3, 118.2,
116.5, 116.2, 116.1, 115.8, 110.8, 110.6, 105.9, 55.5, 39.3 ppm; HRMS
(ESI): m/z calcd for C40H31N2O [M+H]+: 555.2437; found: 555.2411.
[2-Phenyl-3-(phenyl(3-(p-tolyl)indolizin-1-yl)methyl)]-1H-indole
(7d): Green solid; yield 96% (47 mg); Rf =0.6 (20% EtOAc in
hexane); M.P. 190–1928C; FT-IR: n˜ =3058, 1449, 1300, 740,
700 cmÀ1
;
1H NMR (400 MHz, CDCl3): d=8.23 (d, J=7.1 Hz, 1H),
[2-Phenyl-3-(phenyl(3-(thiophen-3-yl)indolizin-1-yl)methyl)]-1H-
indole (7i): Green solid; yield 97% (46.6 mg); Rf =0.5 (20% EtOAc
in hexane); M.P. 126–1288C; FT-IR: n˜ =3065, 1449, 1302, 739,
8.08 (s, 1H), 7.53–7.51 (m, 2H), 7.44–7.30 (m, 10H), 7.26–7.22 (m,
3H), 7.20–7.17 (m, 1H), 7.15–7.11 (m, 1H), 6.97 (d, J=9.0 Hz, 1H),
&
&
Chem. Asian J. 2019, 00, 0 – 0
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4
ꢀ 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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Full Paper
701 cmÀ1
;
1H NMR (400 MHz, CDCl3): d=8.22 (d, J=6.4 Hz, 1H),
8.0 Hz, 1H), 7.29–7.24 (m, 1H), 7.20 (d, J=8.3 Hz, 2H), 7.14–7.10
(m, 1H), 6.97–6.94 (m, 1H), 6.93–6.89 (m, 1H), 6.78 (d, J=8.6 Hz,
2H), 6.73 (s, 1H), 6.49–6.45 (m, 1H), 6.42–6.38 (m, 1H), 6.06 (s, 1H),
3.77 ppm (s, 3H); 13C NMR (100 MHz, CDCl3): d=157.7, 136.8, 136.4,
135.0, 133.2, 132.7, 130.8, 129.8, 128.9, 128.8, 128.7, 128.5, 127.9,
126.8, 124.3, 122.3, 122.0, 121.8, 119.6, 118.2, 116.8, 116.4, 116.0,
115.7, 115.6, 113.5, 110.8, 110.6, 55.3, 38.5 ppm; HRMS (ESI): m/z
calcd for C36H29N2O [M+H]+: 505.2281; found: 505.2259.
8.09 (s, 1H), 7.51–7.49 (m, 2H), 7.43–7.33 (m, 6H), 7.29–7.22 (m,
6H), 7.20–7.11 (m, 2H), 6.98 (d, J=7.9 Hz, 1H), 6.91 (t, J=7.3 Hz,
1H), 6.77 (s, 1H), 6.51–6.44 (m, 2H), 6.10 ppm (s, 1H); 13C NMR
(100 MHz, CDCl3): d=144.6, 136.4, 135.2, 133.19, 133.1, 130.6,
128.9, 128.8, 128.7, 128.5, 128.2, 128.0, 127.7, 125.9, 125.87, 122.7,
122.0, 121.7, 120.2, 119.9, 119.6, 118.0, 116.2, 116.0, 115.9, 115.5,
110.8, 110.7, 39.2 ppm; HRMS (ESI): m/z calcd for C33H25N2S [M+H]+
: 481.1739; found: 481.1725.
[3-((2-Bromophenyl)(3-phenylindolizin-1-yl)methyl)]-2-phenyl-
1H-indole (7o): Green solid; yield 60% (33.1 mg); Rf =0.6 (20%
EtOAc in hexane); M.P. 122–1248C; FT-IR: n˜ =2926, 1460, 1268, 745,
[3-((3-Cyclopropylindolizin-1-yl)(phenyl)methyl)]-2-phenyl-1H-
indole (7j): Green solid; yield 56% (24.6 mg); Rf =0.7 (20% EtOAc
in hexane); M.P. 190–1928C; FT-IR: n˜ =2929, 1450, 1303, 740,
698 cmÀ1 1H NMR (400 MHz, CDCl3): d=8.30 (d, J=6.9 Hz, 1H),
;
700 cmÀ1; H NMR (400 MHz, CDCl3): d=8.06 (s, 1H), 8.01–8.00 (m,
8.12 (s, 1H), 7.62–7.57 (m, 4H), 7.45–7.30 (m, 10H), 7.26–7.22 (m,
1H), 7.19–7.09 (m, 2H), 7.00–6.96 (m, 2H), 6.70 (s, 1H), 6.52–6.48
(m, 1H), 6.43 (t, J=6.6 Hz, 1H), 6.35 ppm (s, 1H); 13C NMR
(100 MHz, CDCl3): d=143.6, 136.2, 135.9, 133.2, 133.1, 132.6, 131.1,
130.7, 128.9, 128.86, 128.6, 128.5, 128.4, 127.9, 127.8, 127.2, 126.8,
125.1, 124.1, 122.2, 121.8, 121.0, 119.6, 118.1, 116.2, 115.9, 115.4,
114.0, 110.9, 110.7, 40.4 ppm; HRMS (ESI): m/z calcd for C35H26BrN2
[M+H]+: 553.1280; found: 553.1257.
1
1H), 7.48–7.47 (m, 2H), 7.41–7.34 (m, 4H), 7.26–7.10 (m, 7H), 6.93–
6.89 (m, 2H), 6.47–6.44 (m, 2H), 6.39 (s, 1H), 6.06 (s, 1H), 1.83–1.77
(m, 1H), 0.93–0.84 (m, 2H), 0.64–0.54 ppm (m, 2H); 13C NMR
(100 MHz, CDCl3): d=145.0, 136.4, 135.0, 133.3, 129.4, 128.8,
128.78, 128.7, 128.5, 128.1, 127.9, 125.8, 125.0, 122.3, 121.9, 121.8,
119.5, 117.7, 116.6, 115.0, 114.1, 113.0, 110.8, 109.6, 39.2, 6.4, 5.5,
5.46 ppm; HRMS (ESI): m/z calcd for C32H27N2 [M+H]+: 439.2175;
found: 439.2157.
[3-((2-Fluorophenyl)(3-phenylindolizin-1-yl)methyl)]-2-phenyl-
1H-indole (7p): Light yellow solid; yield 61% (30 mg); Rf =0.6
(20% EtOAc in hexane); M.P. 136–1388C; FT-IR: n˜ =3059, 1456,
[3-((3-Cyclopentylindolizin-1-yl)(phenyl)methyl)]-2-phenyl-1H-
indole (7k): Green solid; yield 94% (44 mg); Rf =0.6 (20% EtOAc in
hexane); M.P. 171–1738C; FT-IR: n˜ =2956, 1450, 1311, 742,
1302, 739, 700 cmÀ1 1H NMR (400 MHz, CDCl3): d=8.25 (d, J=
;
700 cmÀ1; H NMR (400 MHz, CDCl3): d=8.09 (s, 1H), 7.74–7.72 (m,
7.1 Hz, 1H), 8.10 (s, 1H), 7.53–7.51 (m, 2H), 7.47–7.35 (m, 10H),
7.29–7.26 (m, 1H), 7.21–7.16 (m, 1H), 7.12 (t, J=7.8 Hz, 1H), 7.05–
6.90 (m, 4H), 6.68 (s, 1H), 6.48–6.44 (m, 1H), 6.40 (t, J=6.1 Hz, 1H),
1
1H), 7.49–7.47 (m, 2H), 7.42–7.34 (m, 5H), 7.26–7.21 (m, 4H), 7.19–
7.16 (m, 1H), 7.11 (t, J=7.6 Hz, 1H), 6.92–6.88 (m, 2H), 6.47 (s, 1H),
6.42–6.37 (m, 2H), 6.07 (s, 1H), 3.25–3.18 (m, 1H), 2.18–2.02 (m,
2H), 1.74–1.56 ppm (m, 6H); 13C NMR (100 MHz, CDCl3): d=145.1,
136.4, 135.1, 133.3, 129.5, 128.8 (2C), 128.7, 128.6, 128.0, 127.9,
127.7, 125.7, 122.2, 121.87, 121.8, 119.4, 117.8, 116.6, 114.3, 114.26,
111.2, 110.8, 109.5, 39.3, 36.7, 31.44, 31.37, 25.17, 25.15 ppm; HRMS
(ESI): m/z calcd for C34H31N2 [M+H]+: 467.2488; found: 467.2465.
6.31 ppm (s, 1H); 13C NMR (100 MHz, CDCl3): d=161.0 (d, JC-F
=
245.4 Hz), 136.2, 135.3, 133.2, 132.7, 131.7 (d, JC-F =13.7 Hz), 130.6
(d, JC-F =4.0 Hz), 130.5, 128.9, 128.8, 128.7, 128.6, 128.0, 127.93,
127.9, 126.8, 124.1, 123.8 (d, JC-F =3.4 Hz), 123.0, 121.9, 121.1, 119.6,
118.2, 116.1, 115.8, 115.4 (d, JC-F =21.8 Hz), 115.0, 114.4, 110.9, 110.7,
33.6 ppm (d,
J
C-F =2.9 Hz); 19F NMR (376 MHz, CDCl3): d=
À116.0 ppm; HRMS (ESI): m/z calcd for C35H26FN2 [M+H]+:
[3-((3-Cyclohexylindolizin-1-yl)(phenyl)methyl)]-2-phenyl-1H-
indole (7l): Green solid; yield 74% (35.5 mg); Rf =0.6 (20% EtOAc
in hexane); M.P. 161–1638C; FT-IR: n˜ =2929, 1451, 1321, 744,
493.2081; found: 493.2059.
2-Phenyl-[3-((3-phenylindolizin-1-yl)(4-(trifluoromethyl)phenyl)-
methyl)]-1H-indole (7q): Green solid; yield 75% (40.7 mg); Rf =0.6
(20% EtOAc in hexane); M.P. 130–1328C; FT-IR: n˜ =2929, 1450,
699 cmÀ1 1H NMR (400 MHz, CDCl3): d=8.08 (s, 1H), 7.71 (d, J=
;
6.5 Hz, 1H), 7.49–7.47 (m, 2H), 7.42–7.33 (m, 4H), 7.26–7.21 (m,
5H), 7.19–7.16 (m, 1H), ), 7.12 (t, J=7.4 Hz, 1H), 6.92–6.87 (m, 2H),
6.42 (s, 1H), 6.42–6.35 (m, 2H), 6.06 (s, 1H), 2.79–2.73 (m, 1H),
2.07–1.96 (m, 2H), 1.82–1.73 (m, 3H), 1.45–1.31 ppm (m, 5H);
13C NMR (100 MHz, CDCl3): d=145.1, 136.4, 135.0, 133.3, 129.1,
128.9, 128.8 (2C), 128.7, 128.6, 128.0, 127.9, 125.7, 121.9, 121.86,
121.7, 119.4, 118.0, 116.6, 114.5, 114.2, 110.9, 110.8, 109.5, 39.3, 35.4,
31.8, 31.7, 26.7, 26.7, 26.5 ppm; HRMS (ESI): m/z calcd for C35H33N2
[M+H]+: 481.2644; found:481.2628.
1325, 1121, 741, 700 cmÀ1 1H NMR (400 MHz, CDCl3): d=8.28 (d,
;
J=7.1 Hz, 1H), 8.13 (s, 1H), 7.52–7.37 (m, 13H), 7.30–7.25 (m, 3H),
7.15 (t, J=7.6 Hz, 1H), 6.97–6.92 (m, 2H), 6.72 (s, 1H), 6.54–6.50 (m,
1H), 6.44 (t, J=6.5 Hz, 1H), 6.12 ppm (s, 1H); 13C NMR (100 MHz,
CDCl3): d=148.9, 136.4, 135.5, 133.0, 132.5, 130.9, 129.1, 129.0 (2C),
128.9, 128.7, 128.3, 128.2, 128.0, 127.0, 125.1 (q, JC-F =3.8 Hz), 124.7,
124.6 (q, JC-F =270.2 Hz), 122.4, 122.2, 121.4, 119.8, 117.9, 116.5,
115.5, 115.3, 115.2, 111.0, 110.7, 39.3 ppm; 19F NMR (376 MHz,
CDCl3): d=À62.12 ppm; HRMS (ESI): m/z calcd for C36H26F3N2
[M+H]+: 543.2049; found: 543.2026.
[3-((4-(tertButyl)phenyl)(3-phenylindolizin-1-yl)methyl)]-2-
phenyl-1H-indole (7m): Green solid; yield 92% (49 mg); Rf =0.6
(20% EtOAc in hexane); M.P. 153–1558C; FT-IR: n˜ =2962, 1449,
2-Phenyl-[3-((3-phenylindolizin-1-yl)(4-(trifluoromethoxy)phen-
yl)-methyl)]-1H-indole (7r): Green semi solid; yield 82% (45.8 mg);
Rf =0.7 (20% EtOAc in hexane); FT-IR: n˜ =3058, 1505, 1262, 740,
;
700 cmÀ1 1H NMR (400 MHz, CDCl3): d=8.28 (d, J=7.1 Hz, 1H),
8.11 (s, 1H), 7.53–7.48 (m, 4H), 7.45–7.36 (m, 6H), 7.30–7.26 (m,
4H), 7.17–7.13 (m, 1H), 7.08–7.06 (m, 2H), 6.99–6.93 (m, 2H), 6.75
(s, 1H), 6.54–6.51 (m, 1H), 6.46–6.42 (m, 1H), 6.09 ppm (s, 1H);
13C NMR (100 MHz, CDCl3): d=147.4, 143.4, 136.4, 135.4, 133.0,
132.6, 130.8, 130.1, 129.0, 128.9, 128.7, 128.2, 128.1, 128.0, 127.0,
124.6, 122.4, 122.2, 121.5, 120.7 (q, JC-F =254.9 Hz), 120.6, 119.7,
117.9, 116.4, 115.8, 115.6, 115.4, 111.0, 110.7, 38.7 ppm; 19F NMR
(376 MHz, CDCl3): d=À57.8 ppm; HRMS (ESI): m/z calcd for
C36H26F3N2O [M+H]+: 559.1998; found: 559.1972.
1302, 742, 700 cmÀ1 1H NMR (400 MHz, CDCl3): d=8.24 (d, J=
;
7.1 Hz, 1H), 8.06 (s, 1H), 7.52–7.51 (m, 4H), 7.43–7.35 (m, 7H),
7.29–7.21 (m, 5H), 7.13 (t, J=7.6 Hz, 1H), 6.97–6.91 (m, 2H), 6.77 (s,
1H), 6.48–6.44 (m, 1H), 6.39 (t, J=6.5 Hz, 1H), 6.08 (s, 1H),
1.29 ppm (s, 9H); 13C NMR (100 MHz, CDCl3): d=148.5, 141.4, 136.4,
135.1, 133.3, 132.8, 130.9, 128.9, 128.8, 128.5, 128.4, 128.0, 127.9,
127.8, 126.8, 125.0, 124.3, 122.2, 122.0, 121.9, 119.5, 118.2, 116.8,
116.4, 116.0, 115.6, 110.8, 110.5, 38.7, 34.5, 31.6 ppm; HRMS (ESI):
m/z calcd for C39H35N2 [M+H]+: 531.2801; found: 531.2782.
[3-((4-Methoxyphenyl)(3-phenylindolizin-1-yl)methyl)]-2-phenyl-
1H-indole (7n): Light green solid; yield 56% (28.2 mg); Rf =0.6
(20% EtOAc in hexane); M.P. 216–2188C; FT-IR: n˜ =2926, 1462,
1262, 740, 699 cmÀ1
;
1H NMR (400 MHz, CDCl3): d=8.26–8.24 (m,
{3-([1,1’-Biphenyl]-4-yl(3-phenylindolizin-1-yl)methyl)}-2-phenyl-
1H-indole (7s): Off white solid; yield 75% (41.2 mg); Rf =0.5 (20%
1H), 8.08 (s, 1H), 7.52–7.49 (m, 4H), 7.44–7.34 (m, 6H), 7.30 (d, J=
Chem. Asian J. 2019, 00, 0 – 0
www.chemasianj.org
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ꢀ 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
&
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Full Paper
EtOAc in hexane); M.P. 176–1788C; FT-IR: n˜ =3057, 1487, 1301, 743,
699 cmÀ1 1H NMR (400 MHz, CDCl3): d=8.29 (d, J=7.1 Hz, 1H),
2-(4-(tertButyl)phenyl)-[3-(phenyl(3-phenylindolizin-1-yl)meth-
yl)]-1H-indole (8b): Green solid; yield 80% (42.4 mg); Rf =0.7 (20%
EtOAc in hexane); M.P. 129–1318C; FT-IR: n˜ =2963, 1452, 1265, 740,
;
8.08 (s, 1H), 7.60 (d, J=7.2 Hz, 2H), 7.55–7.53 (m, 4H), 7.50–7.48
(m, 2H), 7.46–7.37 (m, 11H), 7.33–7.26 (m, 2H), 7.15 (t, J=7.1 Hz,
1H), 7.01 (d, J=9.0 Hz, 1H), 6.95 (t, J=7.5 Hz, 1H), 6.81 (s, 1H),
6.53–6.49 (m, 1H), 6.45–6.42 (m, 1H), 6.15 ppm (s, 1H); 13C NMR
(100 MHz, CDCl3): d=143.8, 141.2, 138.6, 136.4, 135.3, 133.2, 132.7,
131.0, 129.3, 128.9, 128.88, 128.8, 128.76, 128.50, 128.0, 127.96,
127.1, 127.0, 126.9 (2C), 124.4, 122.3, 122.0, 121.8, 119.6, 118.2,
116.3, 116.2, 116.1, 115.7, 110.9, 110.6, 39.0 ppm; HRMS (ESI): m/z
calcd for C41H31N2 [M+H]+: 551.2488; found: 551.2471.
700 cmÀ1 1H NMR (400 MHz, CDCl3): d=8.27 (d, J=7.0 Hz, 1H),
;
8.04 (s, 1H), 7.53–7.51 (m, 2H), 7.44–7.23 (m, 13H), 7.20–7.17 (m,
1H), 7.12 (t, J=7.3 Hz, 1H), 6.98 (d, J=9.0 Hz, 1H), 6.90 (t, J=
7.4 Hz, 1H), 6.73 (s, 1H), 6.50–6.47 (m, 1H), 6.42 (t, J=6.6 Hz, 1H),
6.13 (s, 1H), 1.36 ppm (s, 9H); 13C NMR (100 MHz, CDCl3): d=151.0,
144.7, 136.3, 135.2, 132.8, 130.9, 130.3, 128.9 (2C), 128.7, 128.3,
128.1, 127.9, 126.8, 125.9, 125.8, 124.3, 122.3, 121.8, 121.6, 119.5,
118.3, 116.5, 116.0, 115.9, 115.8, 110.7, 110.5, 39.4, 34.8, 31.5 ppm;
HRMS (ESI): m/z calcd for C39H35N2 [M+H]+: 531.2801; found:
531.2782.
[3-(Anthracen-9-yl(3-phenylindolizin-1-yl)methyl)]-2-phenyl-1H-
indole (7t): Yellow solid; yield 53% (30.4 mg); Rf =0.6(20% EtOAc
in hexane); M.P. 132–1358C; FT-IR: n˜ =3054, 1455, 1264, 734,
2-(4-Phenoxyphenyl)-[3-(phenyl(3-phenylindolizin-1-yl)methyl)]-
1H-indole (8c): Green solid; yield 52% (29.4 mg); Rf =0.5 (20%
EtOAc in hexane); M.P. 124–1268C; FT-IR: n˜ =3061, 1488, 1240, 742,
1
699 cmÀ1; H NMR (400 MHz, CDCl3): d=8.49–8.47 (m, 2H), 8.33 (s,
1H), 8.17 (d, J=7.1 Hz, 1H), 7.95–7.92 (m, 3H), 7.50 (s, 1H), 7.40–
7.28 (m, 7H), 7.24–7.17 (m, 3H), 7.13 (d, J=9.0 Hz, 1H), 7.08–7.04
(m, 1H), 7.01–6.95 (m, 3H), 6.90–6.86 (m, 2H), 6.73 (d, J=3.8 Hz,
2H), 6.58 (s, 1H), 6.49–6.45 (m, 1H), 6.39–6.36 ppm (m, 1H);
13C NMR (100 MHz, CDCl3): d=136.7, 135.7, 135.2, 133.3, 132.7,
131.9, 130.8, 130.7, 129.1, 128.8, 128.7, 128.6, 127.9, 127.3, 127.2,
127.15, 126.7, 125.7, 125.1, 124.5, 124.2, 122.2, 121.8, 120.9, 119.6,
118.2, 116.7, 116.4, 116.3, 116.1, 110.6, 110.5, 36.1 ppm; HRMS (ESI):
m/z calcd for C43H31N2 [M+H]+: 575.2488; found: 575.2465.
699 cmÀ1 1H NMR (400 MHz, CDCl3): d=8.26 (d, J=7.1 Hz, 1H),
;
8.06 (s, 1H), 7.52–7.50 (m, 2H), 7.45–7.34 (m, 7H), 7.31–7.22 (m,
6H), 7.20–7.10 (m, 3H), 7.06 (d, J=8.1 Hz, 2H), 7.03 (d, J=8.6 Hz,
2H), 6.98 (d, J=9.0 Hz, 1H), 6.91 (t, J=7.5 Hz, 1H), 6.71 (s, 1H),
6.51–6.47 (m, 1H), 6.41 (t, J=6.5 Hz, 1H), 6.08 ppm (s, 1H);
13C NMR (100 MHz, CDCl3): d=157.3, 156.9, 144.6, 136.3, 134.7,
132.7, 130.9, 130.1, 130.0, 128.9, 128.8, 128.6, 128.2, 128.1, 127.9,
126.8, 126.0, 124.4, 123.8, 122.3, 121.9, 121.6, 119.6, 119.4, 118.8,
118.1, 116.3, 116.1, 116.0, 115.7, 110.8, 110.6, 39.4 ppm; HRMS (ESI):
m/z calcd for C41H31N2O [M+H]+: 567.2437; found: 567.2429.
[3-((9H-Fluoren-2-yl)(3-phenylindolizin-1-yl)methyl)]-2-phenyl-
1H-indole (7u): Green solid; yield 72% (40.5 mg); Rf =0.6 (20%
EtOAc in hexane); M.P. 226–2288C; FT-IR: n˜ =3056, 1455, 1301, 738,
2-(4-Bromophenyl)-[3-(phenyl(3-phenylindolizin-1-yl)methyl)]-
1H-indole (8d): Green solid; yield 48% (26.5 mg); Rf =0.7 (20%
EtOAc in hexane); M.P. 136–1388C; FT-IR: n˜ =3054, 2925, 1452,
700 cmÀ1 1H NMR (400 MHz, CDCl3): d=8.29 (d, J=7.1 Hz, 1H),
;
8.12 (s, 1H), 7.74 (d, J=7.5 Hz, 1H), 7.66 (d, J=7.9 Hz, 1H), 7.55–
7.53 (m, 4H), 7.50–7.47 (m, 2H), 7.45–7.32 (m, 9H), 7.29–7.23 (m,
2H), 7.15–7.10 (m, 1H), 7.00 (d, J=8.9 Hz, 1H), 6.92–6.88 (m, 1H),
6.78 (s, 1H), 6.51–6.47 (m, 1H), 6.43 (td, J=7.1, 1.4 Hz, 1H), 6.18 (s,
1H), 3.79 ppm (s, 2H); 13C NMR (100 MHz, CDCl3): d=143.7, 143.5,
143.4, 141.9, 139.6, 136.4, 135.1, 133.2, 132.7, 130.9, 128.9, 128.8,
128.7, 128.6, 127.94, 127.91, 127.6, 126.8, 126.7, 126.3, 125.4, 125.1,
124.4, 122.3, 122.0, 121.8, 119.7, 119.6, 119.5, 118.2, 116.6, 116.4,
116.1, 115.8, 110.8, 110.6, 39.5, 37.1 ppm; HRMS (ESI): m/z calcd for
C42H31N2 [M+H]+: 563.2488; found: 563.2463.
1302, 742, 701 cmÀ1 1H NMR (400 MHz, CDCl3): d=8.26 (d, J=
;
7.1 Hz, 1H), 8.10 (s, 1H), 7.51–7.49 (m, 4H), 7.41 (t, J=7.5 Hz, 2H),
7.36–7.31 (m, 3H), 7.29–7.22 (m, 6H), 7.20–7.16 (m, 1H), 7.15–7.11
(m, 1H), 6.97 (d, J=9.0 Hz, 1H), 6.94–6.90 (m, 1H), 6.69 (s, 1H),
6.53–6.49 (m, 1H), 6.44–6.41 (m, 1H), 6.03 ppm (s, 1H); 13C NMR
(100 MHz, CDCl3): d=144.4, 136.4, 133.9, 132.6, 132.1, 131.9, 130.8,
130.2, 128.9, 128.8, 128.5, 128.2, 127.9, 126.9, 126.1, 124.4, 122.4,
122.3, 122.1, 121.7, 119.8, 118.0, 116.7, 116.3, 116.0, 115.7, 110.9,
110.6, 39.4 ppm; HRMS (ESI): m/z calcd for C35H26BrN2 [M+H]+:
553.1280; found: 553.1255.
[1-Phenyl-3-(phenyl(2-phenyl-1H-indol-3-yl)methyl)]pyrrolo[1,2-
a]-quinoline (7v) : Pale yellow solid; yield 83% (43.5 mg); Rf =0.6
(20% EtOAc in hexane); M.P. 140–1428C; FT-IR: n˜ =3054, 2926,
2-(3-Fluorophenyl)-[3-(phenyl(3-phenylindolizin-1-yl)methyl)]-
1H-indole (8e): Off white solid; yield 80% (39.4 mg); Rf =0.6 (20%
EtOAc in hexane); M.P. 196–1988C; FT-IR: n˜ =3060, 1452, 1300, 741,
1448, 1309, 741, 701 cmÀ1 1H NMR (400 MHz, CDCl3): d=8.09 (s,
;
1H), 7.56–7.35 (m, 13H), 7.31–7.21 (m, 5H), 7.19–7.15 (m, 2H),
7.14–7.06 (m, 2H), 6.97 (d, J=9.3 Hz, 1H), 6.90 (t, J=7.4 Hz, 1H),
6.82 (d, J=9.4 Hz, 1H), 6.58 (s, 1H), 6.10 ppm (s, 1H); 13C NMR
(100 MHz, CDCl3): d=144.5, 136.4, 135.8, 135.3, 134.5, 133.2, 129.7,
129.4, 129.3, 128.9, 128.8, 128.7, 128.5, 128.46, 128.4, 128.2, 128.0,
127.4, 126.3, 126.0, 125.6, 123.2, 122.0, 121.7, 119.7, 119.3, 118.4,
118.0, 117.8, 117.6, 116.1, 110.9, 39.1 ppm; HRMS (ESI): m/z calcd for
C39H29N2 [M+H]+: 525.2331; found: 525.2310.
699 cmÀ1 1H NMR (400 MHz, CDCl3): d=8.27 (d, J=7.1 Hz, 1H),
;
8.06 (s, 1H), 7.53–7.51 (m, 2H), 7.42 (t, J=7.6 Hz, 2H), 7.37–7.33 (m,
2H), 7.31–7.24 (m, 7H), 7.21–7.18 (m, 2H), 7.17–7.13 (m, 1H), 7.06
(td, J=8.4, 1.8 Hz, 1H), 7.00 (d, J=9.0 Hz, 1H), 6.93 (t, J=7.3 Hz,
1H), 6.72 (s, 1H), 6.54–6.50 (m, 1H), 6.45–6.41(m, 1H), 6.10 ppm (s,
1H); 13C NMR (100 MHz, CDCl3): d=162.9 (d, JC-F =245.0 Hz), 144.4,
136.5, 135.3 (d, JC-F =8.1 Hz), 133.8 (d, JC-F =2.3 Hz), 132.6, 130.8,
130.3 (d, JC-F =8.5 Hz), 128.9, 128.8, 128.4, 128.2, 127.9, 126.9, 126.0,
124.41, 124.40, 122.3 (d, JC-F =1.9 Hz), 121.8, 119.8, 118.0, 116.9,
116.3, 116.0, 115.6, 115.5 (d, JC-F =22.1 Hz), 114.8, 114.6, 111.0, 110.6,
39.3 ppm; 19F NMR (376 MHz, CDCl3): d=À112.2 ppm; HRMS (ESI):
m/z calcd for C35H26FN2 [M+H]+: 493.2081; found: 493.2062.
[3-Phenyl-1-(phenyl(2-phenyl-1H-indol-3-yl)methyl)]pyrrolo[2,1-
a]-isoquinoline (7w): Off white solid; yield 44% (23 mg); Rf =0.6
(20% EtOAc in hexane); M.P. 148–1508C; FT-IR: n˜ =3057, 1455,
1337, 739, 699 cmÀ1 1H NMR (400 MHz, CDCl3): d=8.12 (s, 1H),
;
8.01 (d, J=7.5 Hz, 1H), 7.66 (d, J=8.2 Hz, 1H), 7.51–7.41 (m, 8H),
7.37–7.30 (m, 8H), 7.28–7.24 (m, 1H), 7.21–7.17 (m, 2H), 7.14–7.10
(m, 1H), 7.04–7.00 (m, 1H), 6.92–6.88 (m, 1H), 6.65 (d, J=7.5 Hz,
1H), 6.59 (s, 1H), 6.37 ppm (s, 1H); 13C NMR (100 MHz, CDCl3): d=
144.6, 136.4, 135.5, 133.2, 132.4, 129.2, 129.1, 128.9, 128.8 (2C),
128.4, 128.38, 127.9, 127.8, 127.4, 127.3, 127.1, 126.8, 126.4, 126.1,
125.8, 124.7, 123.7, 122.5, 122.0, 121.7, 121.0, 119.7, 115.7, 115.5,
111.0, 110.8, 42.0 ppm; HRMS (ESI): m/z calcd for C39H29N2 [M+H]+:
525.2331; found: 525.2312.
Methyl 4-[(3-(phenyl(3-phenylindolizin-1-yl)methyl)-1H-indol-2-
yl)]-benzoate (8 f): Green solid; yield 61% (32.4 mg); Rf =0.3 (20%
EtOAc in hexane); M.P. 194–1968C; FT-IR: n˜ =3058, 1722, 1435,
1281, 741, 701 cmÀ1 1H NMR (400 MHz, CDCl3): d=8.26 (d, J=
;
7.1 Hz, 1H), 8.23 (s, 1H), 8.05 (d, J=8.2 Hz, 2H), 7.55 (d, J=8.2 Hz,
2H), 7.51–7.50 (m, 2H), 7.40 (t, J=7.5 Hz, 2H), 7.37 (d, J=8.4 Hz,
1H), 7.31–7.23 (m, 6H), 7.20–7.19 (m, 1H), 7.17–7.13 (m, 1H), 6.99
(d, J=9.0 Hz, 1H), 6.92 (t, J=7.8 Hz, 1H), 6.71 (s, 1H), 6.54–6.50 (m,
1H), 6.43 (t, J=6.9 Hz, 1H), 6.10 (s, 1H), 3.94 ppm (s, 3H); 13C NMR
&
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(100 MHz, CDCl3): d=167.0, 144.3, 137.7, 136.7, 133.9, 132.6, 130.8,
130.0, 129.1, 128.9, 128.8, 128.5, 128.4, 128.2, 127.9, 126.9, 126.1,
124.5, 122.6, 122.4, 121.9, 119.9, 117.9, 117.7, 116.4, 115.9, 115.6,
111.0, 110.7, 52.4, 39.4 ppm; HRMS (ESI): m/z calcd for C37H29N2O2
[M+H]+: 533.2230; found: 533.2207.
Mohali for a postdoctoral fellowship. SM thanks UGC, New
Delhi for a research fellowship. The NMR and HRMS facilities at
IISER Mohali are gratefully acknowledged.
4-[(3-(Phenyl(3-phenylindolizin-1-yl)methyl)-1H-indol-2-yl)]-ben-
zonitrile (8g): Yellow solid; yield 42% (21 mg); Rf =0.3 (20% EtOAc
in hexane); M.P. 188–1908C; FT-IR: n˜ =2925, 2227, 1607, 1453,
Conflict of interest
The authors declare no conflict of interest.
1305, 742, 701 cmÀ1 1H NMR (400 MHz, CDCl3): d=8.25 (d, J=
;
7.0 Hz, 1H), 8.11 (s, 1H), 7.63–7.61 (m, 2H), 7.54–7.52 (m, 2H), 7.51–
7.46 (m, 2H), 7.43–7.37 (m, 3H), 7.30–7.16 (m, 8H), 6.96–6.92 (m,
2H), 6.64 (s, 1H), 6.55–6.51 (m, 1H), 6.46–6.43 (m, 1H), 6.05 ppm (s,
1H); 13C NMR (100 MHz, CDCl3): d=144.0, 137.7, 136.8, 133.0,
132.5, 132.4, 130.7, 129.0, 128.9, 128.8, 128.5, 128.3, 127.9, 127.0,
126.3, 124.6, 123.1, 122.5, 122.0, 120.2, 118.9, 118.4, 117.8, 116.6,
115.7, 115.6, 111.1, 111.0, 110.8, 39.5 ppm; HRMS (ESI): m/z calcd for
C36H26N3 [M+H]+: 500.2127; found: 500.2106.
Keywords: 5-endo-dig Cyclization
Heterocycles · Indolizine · Triarylmethanes
·
Domino reactions
·
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3-(Phenyl(3-phenylindolizin-1-yl)methyl)-2-(thiophen-3-yl)-1H-
indole (8h): Green solid; yield 90% (43.2 mg); Rf =0.6 (20% EtOAc
in hexane); M.P. 160–1628C; FT-IR: n˜ =2926, 1459, 1351, 741,
699 cmÀ1 1H NMR (400 MHz, CDCl3): d=8.27 (d, J=7.1 Hz, 1H),
;
8.07 (s, 1H), 7.51 (d, J=7.3 Hz, 2H), 7.42–7.38 (m, 3H), 7.35–7.23
(m, 8H), 7.19 (d, J=7.8 Hz, 2H), 7.11 (t, J=7.3 Hz, 1H), 7.02 (d, J=
9.0 Hz, 1H), 6.90–6.86 (m, 1H), 6.67 (s, 1H), 6.52–6.49 (m, 1H), 6.42
(t, J=6.4 Hz, 1H), 6.14 ppm (s, 1H); 13C NMR (100 MHz, CDCl3): d=
144.5, 136.1, 133.7, 132.7, 130.9, 130.7, 128.9, 128.85, 128.6, 128.2,
127.9, 127.5, 126.8, 126.3, 126.0, 124.4, 122.9, 122.4, 122.0, 121.5,
119.6, 118.1, 116.2, 116.21, 116.16, 115.7, 110.8, 110.6, 39.5 ppm;
HRMS (ESI): m/z calcd for C33H25N2S [M+H]+: 481.1739; found:
481.1720.
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2-Cyclopropyl-[3-(phenyl(3-phenylindolizin-1-yl)methyl)]-1H-
indole (8i): Green solid; yield 50% (22 mg); Rf =0.6 (20% EtOAc in
hexane); M.P. 108–1108C; FT-IR: n˜ =2929, 1427, 1301, 742,
701 cmÀ1 1H NMR (400 MHz, CDCl3): d=8.28 (d, J=7.2 Hz, 1H),
;
7.64 (s, 1H), 7.53–7.50 (m, 2H), 7.42–7.38 (m, 2H), 7.35–7.33 (m,
2H), 7.29–7.26 (m, 1H), 7.24 (d, J=8.0 Hz, 3H), 7.21–7.16 (m, 3H),
7.06–7.02 (m, 1H), 6.90–6.56 (m, 1H), 6.66 (s, 1H), 6.55–6.51 (m,
1H), 6.44–6.41 (m, 1H), 6.18 (s, 1H), 2.00–1.94 (m, 1H), 0.93–0.85
(m, 2H), 0.76–0.65 ppm (m, 2H); 13C NMR (100 MHz, CDCl3): d=
144.7, 136.1, 134.9, 132.8, 131.1, 128.9, 128.8, 128.6, 128.1, 127.9,
126.8, 125.9, 124.2, 122.3, 121.0, 120.0, 119.3, 118.3, 116.4, 116.3,
116.0, 115.7, 110.6, 110.3, 39.2, 7.9, 6.7, 6.4 ppm; HRMS (ESI): m/z
calcd for C32H27N2 [M+H]+: 439.2175; found: 439.2157.
6-Chloro-2-phenyl-[3-(phenyl(3-phenylindolizin-1-yl)methyl)]-1H-
indole (8j): Off white solid; yield 70% (35.6 mg); Rf =0.6 (20%
EtOAc in hexane); M.P. 150–1528C; FT-IR: n˜ =3059, 1449, 1301, 740,
1
700 cmÀ1; H NMR (400 MHz, CDCl3): d=8.28–8.26 (m, 1H), 8.08 (s,
1H), 7.53–7.47 (m, 4H), 7.44–7.36 (m, 5H), 7.33 (d, J=1.7 Hz, 1H),
7.30–7.24 (m, 5H), 7.23–7.19 (m, 1H), 7.18–7.16 (m, 1H), 6.97–6.94
(m, 1H), 6.87 (dd, J=8.6, 1.9 Hz, 1H), 6.68 (s, 1H), 6.52–6.48 (m,
1H), 6.43 (td, J=7.1, 1.4 Hz, 1H), 6.07 ppm (s, 1H); 13C NMR
(100 MHz, CDCl3): d=144.4, 136.8, 135.8, 132.7, 132.6, 130.9, 129.0,
128.9, 128.8, 128.6, 128.3, 128.2, 127.9, 127.8, 127.2, 126.9, 126.1,
124.5, 122.5, 122.4, 120.4, 118.1, 116.3, 116.28, 116.0, 115.5, 110.8,
110.7, 39.2 ppm. HRMS (ESI): m/z calcd for C35H26ClN2 [M+H]+:
509.1785; found: 509.1764.
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Acknowledgements
The authors gratefully acknowledge IISER Mohali for providing
financial support and infrastructure. Dr. DKP thanks IISER
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1
characterized by H and 13C NMR spectroscopy.
Manuscript received: July 15, 2019
Revised manuscript received: September 3, 2019
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Accepted manuscript online: September 3, 2019
Version of record online: && &&, 0000
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Chem. Asian J. 2019, 00, 0 – 0
www.chemasianj.org
8
ꢀ 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÝÝ These are not the final page numbers!

Full Paper
FULL PAPER
Dilip K. Paluru, Sriram Mahesh,
Feroz Ahmad, Ramasamy Vijaya Anand*
&& – &&
A Cascade Synthesis of Hetero-
arylated Triarylmethanes Through a
Double 5-endo-dig Cyclization
Sequence
Every cloud has a silver lining: A
silver-catalyzed double 5-endo-dig cycli-
zation cascade for the synthesis of
hetero-arylated unsymmetrical triaryl-
methanes is described.
Chem. Asian J. 2019, 00, 0 – 0
www.chemasianj.org
9
ꢀ 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
&
&
These are not the final page numbers! ÞÞ