Construction of benzo-fused indolizines, pyrrolo[1,2-a]quinolines via alkyne-carbonyl metathesis

Article abstract of DOI:10.1039/c5ob01383f

The strategic use of a sequential Sonogashira coupling/intramolecular alkyne-carbonyl metathesis process for the synthesis of a pyridine ring from 1-(2-haloaryl)-1H-pyrrole-2-carbaldehydes allowed ready access to diverse novel benzo-fused indolizines, pyr

Full text of DOI:10.1039/c5ob01383f

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Page 1 of 35
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Construction of Benzo-fused Indolizines, Pyrrolo[1,2-a]quinolines, via
Alkyne-Carbonyl Metathesis
Maloy Nayak and Ikyon Kim*
College of Pharmacy and Yonsei Institute of Pharmaceutical Sciences, Yonsei University
85 Songdogwahakꢀro, Yeonsuꢀgu, Incheon 406ꢀ840, Republic of Korea
* Corresponding author. Tel.: +82 32 749 4515; fax: +82 32 749 4105; eꢀmail:
ikyonkim@yonsei.ac.kr
Table of Contents
Abstract: Strategic use of a sequential Sonogashira coupling/intramolecular alkyneꢀcarbonyl
metathesis process for the synthesis of pyridine ring from 1ꢀ(2ꢀhaloaryl)ꢀ1Hꢀpyrroleꢀ2ꢀ
carbaldehydes allowed ready access to a diverse novel benzoꢀfused indolizines, pyrrolo[1,2ꢀ
a]quinolines, in good to excellent yields. As a hybrid structure of indolizine and quinoline,
the resulting scaffold has an acyl substituent at C5 position, which is difficult to make by any
other known approaches.

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Keywords: Hybrid Structure; Pyrrolo[1,2ꢀa]quinoline; Indolizine; Quinoline; Sonogashira
coupling; Alkyneꢀcarbonyl metathesis; Diversityꢀoriented synthesis.
Introduction
Alkyneꢀcarbonyl metathesis (ACM) is a synthetic transformation that α,β–unsaturated
carbonyl compounds arise from alkyne and carbonyl functional groups through a [2+2]
cycloaddition and cycloreversion process.1 As the resulting α,β–unsaturated carbonyl group
is a highly versatile functionality, this reaction often provides an opportunity for domino
processes by its being coupled with other subsequent reactions such as Nazarov cyclization
and intramolecular azaꢀMichael addition.2 Another interesting feature of ACM is that it
allows facile access to a number of carboꢀ and heterocycles when these two functional groups
are appropriately linked (Scheme 1(a)). Indeed, construction of several ring systems such as
cycloalkenone and chromenone was realized by this concept.3
Scheme 1. Synthetic Approach to Indolizine via ACM

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In connection with our research interest on design and synthesis of novel indolizines with
distinctive substitution pattern,4 we wish to employ intramolecular ACM reaction to gain
access to a pyridine moiety of indolizine from pyrroleꢀ2ꢀcarboxaldehydes possessing a
suitably situated triple bond (Scheme 1(b)). For this purpose, we envisioned that 1ꢀ(2ꢀ
iodoaryl)ꢀ1Hꢀpyrroleꢀ2ꢀcarbaldehydes would be converted to benzoꢀfused indolizines,
pyrrolo[1,2ꢀa]quinolines, through a sequential Sonogashira coupling/intramolecular ACM
process (Scheme 1(c)). The resulting product 2 can be viewed as a hybrid structure5 of 7ꢀ
acylindolizine6 and 4ꢀacylquinoline,7 two important pharmacophores, which would be
useful for biological screening.8 Previous syntheses of this skeleton have been disclosed in
the literature.9 For example, Fürstner developed hydroarylation of alkyneꢀcontaining biaryl
derivatives and Lautens applied palladiumꢀcatalyzed annulation of aryl heterocycles with
strained alkenes to get access to this backbone, respectively. More recently, Wang reported
the synthesis of pyrrolo[1,2ꢀa]quinolines via Ce(III)ꢀcatalyzed [3+2] annulation of 2ꢀ
alkylazaarenes with nitroolefins. Notably, while there are several methods which enable
installation of aryl, alkyl, or acyl group at C4 site of this nucleus, construction of pyrrolo[1,2ꢀ
a]quinolines bearing an acyl group at C5 position has been very rare.10
Results and discussion
The required 1ꢀ(2ꢀiodoaryl)ꢀ1Hꢀpyrroleꢀ2ꢀcarbaldehydes 1 for this study were prepared by
adopting a procedure consisting of PaalꢀKnorr pyrrole synthesis and Vilsmeier Haack
formylation (Scheme 2). 11 Thus, acidꢀcatalyzed reaction of 2ꢀiodoaniline and 2,5ꢀ
dimethoxytetrahydrofuran cleanly afforded the desired pyrrole 3a, which was converted to 4a
along with 4a’ upon subsequent formylation. Sonogashira coupling reaction of 4a with

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phenylacetylene occurred in acetonitrile as solvent at 70 °C, furnishing the coupled product
5a in 95.2% yield.
Scheme 2. Synthesis of 5a
a
A mixture of 2ꢀiodoaniline (4.57 mmol), 2,5ꢀdimethoxytetrahydrofuran (0.62 mL, 1.05
equiv), and AcOH (0.32 mL, 1.22 equiv) in DCE (8.5 mL) and H2O (5.0 mL) was heated at
80 °C. A mixture of 3a (3.72 mmol) and POCl3 (0.69 mL, 2.0 equiv) in DMF (4 mL) was
stirred at rt. A mixture of 4a (0.4 mmol), phenylacetylene (0.049 mL, 1.1 equiv),
(Ph3P)2PdCl2 (14 mg, 0.05 equiv), CuI (3.9 mg, 0.05 equiv), and Et3N (0.113 mL, 2.0 equiv)
in CH3CN (1.5 mL) was heated at 70 °C.
Optimal conditions for ACM via exposure of 5a to several acidic media were then examined
and the results are summarized in Table 1. When 5a was treated with either catalytic or
stoichiometric amount of BF3ꢀEt2O at rt, no reaction occurred (entries 1 and 2). Elevating the
reaction temperature to 80 °C gave the desired product 6a in 30% yield while increasing the
amount of BF3ꢀEt2O to 1.5 equiv did not result in better chemical yield (entries 3 and 4). Use
of other Lewis acids such as In(OTf)3, InCl3, or AgOTf provided the similar results (entries 5ꢀ
7). To our delight, reaction of 5a in formic acid at 100 °C furnished 6a in 62% yield (entry 8).

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Finally, we were pleased to find that the desired product was cleanly obtained under TFA at
90 °C (entry 9).
Table 1. Reaction Optimization for Alkyne-Aldehyde Metathesisa
entry
catalyst (equiv)
BF3ꢀEt2O (0.5)
BF3ꢀEt2O (1.2)
BF3ꢀEt2O (1.2)
BF3ꢀEt2O (1.5)
In(OTf)3 (0.2)
InCl3 (1.5)
temperature
time (hr)
12
solvent
DCE
DCE
DCE
DCE
DCE
DCE
DCE
ꢀc
yield (%)b
1
2
3
4
5
6
7
8
9
rt
rt
n.r.
n.r.
30
28
23
22
15
62
99
12
80
70
80
80
80
100
90
16
16
16
12
AgOTf (1.5)
HCO2H
12
0.5
1
TFA
ꢀc
a
A mixture of 5a (0.1 mmol) and catalyst in solvent (0.5 mL) was stirred at the indicated
b
c
temperature and time unless otherwise noted. Isolated yield (%) Formic acid or TFA was
used as solvent.
Formation of 6a from 5a can be rationalized based on the mechanism previously proposed
(Scheme 3). Addition of TFA to the alkyne unit in 5a would generate A, which then
undergoes intramolecular aldol/dehydration to give rise to 6a. Alternatively, it can be
understood via alkyne addition to aldehyde promoted by initial protonation (B). Attack of the
resulting carbocation by the neighboring hydroxyl group (C) followed by [2+2]
cycloreversion (D) would lead to 6a.
Scheme 3. Proposed ACM Mechanism

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O
Ph
O
O
O
F3C
Ph
O
TFA
aldol
Ph
N
N
Path a
N
5a
TFA
A
6a
Path b
Ph
OH
O
OH
Ph
Ph
N
N
N
B
C
D
Having established a new and efficient synthetic route to pyrrolo[1,2ꢀa]quinoline skeleton by
way of a sequential Sonogashira coupling/ACM procedure, we first examined the reaction
scope by reacting 4a with several other alkynes (Scheme 4). Under optimized conditions,
several alkynes were installed to afford the corresponding 5b-5j in good yields. Submission
of the resulting coupled products 5b-5g to TFA led to the desired cyclized compounds 6b-6g
in excellent yields (entries 1ꢀ6). Electron density of the aryl moiety in 5 did not seem to affect
the reaction efficiency. ACM of substrate having a heteroaryl group such as thiophene
proceeded well to give the corresponding product (entry 5). Using a mixture of TFA/DCE
(1:1) provided better isolated yields in cases of 5d-5g than using neat TFA. However,
exposure of cyclohexeneꢀcontaining substrate 5h to these conditions provided 6h in low yield
presumably due to decomposition of the product (entry 7). Unfortunately, little or no
conversion was observed with compounds possessing a cyclopentyl or nꢀbutyl group (entries
8 and 9).

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Scheme 4. Synthesis of Diverse Pyrrolo[1,2-a]quinolines via Reactions of 4a with Several
Alkynesa
entry
alkyne (R)
4ꢀFC6H4
5 (%)b
6 (%)b
6b (92.7)
6c (82.8)
6d (82)c
6e (84)c
6f (81)c
6g (87)c
6h (32.6)
trace
1
2
3
4
5
6
7
8
9
5b (90.8)
5c (91.3)
5d (75.8)
5e (71.7)
5f (74.3)
5g (63.6)
5h (95)
3ꢀFC6H4
3ꢀMeC6H4
4ꢀMeOC6H4
3ꢀthiophene
6ꢀMeOꢀ2ꢀnaphthalene
1ꢀcyclohexene
cyclopentyl
nꢀBu
5i (77.4)
5j (77.3)
n.r.
a A mixture of 4a (0.4 mmol), alkyne (1.1 equiv), (Ph3P)2PdCl2 (14 mg, 0.05 equiv), CuI (3.9
mg, 0.05 equiv), and Et3N (0.11 mL, 2.0 equiv) in CH3CN (1.5 mL) was heated at 70 °C. A
b
mixture of 5 (0.1 mmol) in TFA (0.5 mL) was stirred at 90 °C unless otherwise stated.
Isolated yield (%) c A mixture of 5 (0.1 mmol) in TFA/DCE (1:1, 1 mL) was stirred at 90 °C.
Generality of this reaction was further investigated by exposing several other 4b-4e12 to
these conditions (Scheme 5). Irrespective of the electronic properties of iodoaryl rings, the
whole sequence proceeded smoothly to give the products in good yields except for the cases
of ACM reactions of substrates bearing a cyclohexene unit, 5o and 5t.
Scheme 5. Synthesis of Diverse Pyrrolo[1,2-a]quinolines via Reactions of 4b-4e with
Several Alkynesa

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R
R
O
O
O
(Ph3P)2PdCl2
CuI, Et3N
R
A
I
TFA
N
N
N
90 C
CH3CN
70 C
A
A
B
B
B
4b-4e
5k-5x
6i-6v
entry
alkyne (R)
Ph
5 (%)b
6 (%)b
6i (83.5)
6j (77)
4
1
2
4b (A = H, B = Cl)
5k (90.3)
5l (86.2)
5m (83.2)
5n (69.4)
5o (72)
4ꢀFC6H4
4b
3
4ꢀMeOC6H4
3ꢀthiophene
1ꢀcyclohexene
Ph
6k (86)
4b
4
6l (84)
4b
5
6m (34.6)c
6n (86.2)
6o (89.5)
6p (82.7)
6q (83.6)
6r (34)c
6s (88)
4b
6
4c (A = Me, B = H)
5p (92.2)
5q (82)
7
4ꢀFC6H4
4c
8
4ꢀMeOC6H4
3ꢀthiophene
1ꢀcyclohexene
Ph
5r (83.6)
5s (89.5)
5t (85.2)
5u (83.3)
5v (85.7)
5w (82.2)
5x (80)
4c
9
4c
10
11
12
13
14
4c
4d (A = CO2Me, B = H)
4ꢀMeOC6H4
Ph
6t (82)
4d
4e (A = NO2, B = H)
4e
6u (86)
3ꢀMeC6H4
6v (88.2)
a
A mixture of 4b-4e (0.36 mmol), alkyne (1.1 equiv), (Ph3P)2PdCl2 (0.05 equiv), CuI (0.05
equiv), and Et3N (2.0 equiv) in CH3CN (1.5 mL) was heated at 70ꢀ80 °C. A mixture of 5 (0.1
b
mmol) in TFA (0.5 mL) was stirred at 90 °C unless otherwise stated. Isolated yield (%) c A
mixture of 5 (0.1 mmol) in TFA/DCE (1:1, 1 mL) was stirred at 90 °C.
In addition, the chemistry described above was applied to 2ꢀbromoꢀ4ꢀmethylaniline to expand
the substrate scope (Scheme 6). Thus, 1ꢀ(2ꢀbromoꢀ4ꢀmethylphenyl)ꢀ1Hꢀpyrroleꢀ2ꢀ
carbaldehyde 8 was prepared by following the similar procedure for 4a. Again, 8 underwent
Sonogashira crossꢀcoupling with phenylacetylene to furnish 5p in 82% yield.
Scheme 6. Use of 2-Bromoaniline for the Synthesis of 5pa

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a
A mixture of 2ꢀbromoꢀ4ꢀmethylaniline (2.69 mmol), 2,5ꢀdimethoxytetrahydrofuran (0.37
mL, 1.05 equiv), and AcOH (0.15 mL, 1.22 equiv) in DCE (4 mL) and H2O (2.5 mL) was
heated at 80 °C. A mixture of 7 (1.06 mmol) and POCl3 (0.2 mL, 2.0 equiv) in DMF (2 mL)
was stirred at rt. A mixture of 8 (0.19 mmol), phenylacetylene (0.02 mL, 1.1 equiv),
(Ph3P)2PdCl2 (13 mg, 0.1 equiv), CuI (3.6 mg, 0.1 equiv), and Et3N (0.053 mL, 2.0 equiv) in
CH3CN (1 mL) was heated at 90 °C.
In summary, we have accomplished a highly efficient synthesis of a novel benzoꢀfused
indolizines, pyrrolo[1,2ꢀa]quinolines, by way of a sequential Sonogashira crossꢀ
coupling/intramolecular alkyneꢀcarbonyl metathesis process to construct the central pyridine
ring. Several 1ꢀ(2ꢀhaloaryl)ꢀ1Hꢀpyrroleꢀ2ꢀcarbaldehydes readily prepared by way of Paalꢀ
Knorr pyrrole ring synthesis and subsequent Vilsmeier Haack formylation of commercially
available 2ꢀhaloanilines were successfully converted to various pyrrolo[1,2ꢀa]quinolines with
an acyl substituent at C5 site, which cannot be accessed by any other synthetic methods.
Unprecedented substitution pattern of this nucleus should be useful to explore its various
biological functions. Application of this protocol for the synthesis of other heterocycles as
well as investigation on utility of these compounds are currently in progress.

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Experimental Section
General Methods
Unless specified, all reagents and starting materials were purchased from commercial sources
and used as received without purification. “Concentrated” refers to the removal of volatile
solvents via distillation using a rotary evaporator. “Dried” refers to pouring onto, or passing
through, anhydrous magnesium sulfate followed by filtration. Flash chromatography was
performed using silica gel (230−400 mesh) with hexanes, ethyl acetate, and dichloromethane
as eluent. All reactions were monitored by thinꢀlayer chromatography on 0.25 mm silica
1
plates (Fꢀ254) visualizing with UV light. H and 13C NMR spectra were recorded on 400
MHz NMR spectrometer and were described as chemical shifts, multiplicity (s, singlet; d,
doublet; t, triplet; q, quartet; m, multiplet), coupling constant in hertz (Hz), and number of
protons. IR spectra were recorded on FTꢀIR using diamond ATR technique and were
described as wavenumbers (cmꢀ1). HRMS were measured with electrospray ionization (ESI)
and QꢀTOF mass analyzer.
Representative Procedure for the Synthesis of 3a
To a stirred solution of 2ꢀiodoaniline (1 g, 4.57 mmol), AcOH (0.32 mL, 1.22 equiv) and H2O
(5.0 mL) in DCE (8.5 mL) at 80 °C was added 2,5ꢀdimethoxytetrahydrofuran (0.62 mL, 1.05
equiv) in one portion and heating was continued at 80 °C for 12 h. After cooling, layers were
separated and the aqueous layer was extracted with CH2Cl2 (2 x 30 mL). The combined
organic layer was dried over anhydrous MgSO4 and concentrated under reduced pressure to
afford the crude product which was purified by flash chromatography on silica gel (hexanes:
EtOAc, 95:5) to furnish 3a as colorless oil (1.21 g, 98.5%).
1-(2-Iodophenyl)-1H-pyrrole (3a). Brown oil (1.21 g, 98.5%), 1H NMR (400 MHz, CDCl3)
δ 7.94 (dd, J = 1.1, 8.1 Hz, 1H), 7.39ꢀ7.43 (m, 1H), 7.31 (dd, J = 1.4, 7.8 Hz, 1H), 7.10 (dt, J

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= 1.6, 7.9 Hz, 1H), 6.82 (t, J = 2.1 Hz, 2H), 6.34 (t, J = 2.1 Hz, 2H); 13C NMR (100 MHz,
CDCl3) δ 144.1, 140.0, 129.5, 129.0, 128.1, 122.2, 109.2, 95.9; HRMS (ESIꢀQTOF) m/z
[M+H]+ calcd for C10H9IN 269.9774, found 269.9785.
3b-3d were prepared by following the similar procedure for 3a.
1-(5-Chloro-2-iodophenyl)-1H-pyrrole (3b). Brown oil (1.14 g, 95%), 1H NMR (400 MHz,
CDCl3) δ 7.85 (d, J = 8.5 Hz, 1H), 7.31 (d, J = 2.4 Hz, 1H), 7.11 (dd, J = 2.4, 8.4 Hz, 1H),
6.81 (t, J = 2.0 Hz, 2H), 6.35 (t, J = 2.0 Hz, 2H); 13C NMR (100 MHz, CDCl3) δ 145.1, 140.8,
135.0, 129.6, 128.4, 122.1, 109.8, 92.9; HRMS (ESIꢀQTOF) m/z [M+Na]+ calcd for
C10H7ClINNa 325.9204, found 325.9215.
1
1-(2-Iodo-4-methylphenyl)-1H-pyrrole (3c). Brown oil (2.41 g, 99.2%), H NMR (400
MHz, CDCl3) δ 7.77 (s, 1H), 7.18ꢀ7.22 (m, 2H), 6.79 (t, J = 1.9 Hz, 2H), 6.33 (t, J = 2.0 Hz,
2H), 2.38 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 141.6, 140.3, 139.7, 129.7, 127.6, 122.3,
109.0, 95.9, 20.6; HRMS (ESIꢀQTOF) m/z [M+H]+ calcd for C11H11IN 283.9931, found
283.9924.
Methyl 3-iodo-4-(1H-pyrrol-1-yl)benzoate (3d). White solid, mp: 110.3ꢀ111.8 °C (412 mg,
97%); 1H NMR (400 MHz, CDCl3) δ 8.61 (d, J = 1.6 Hz, 1H), 8.06 (dd, J = 1.6, 8.2 Hz, 1H),
7.33 (d, J = 8.2 Hz, 1H), 6.86 (t, J = 1.8 Hz, 2H), 6.36 (t, J = 1.9 Hz, 2H), 3.95 (s, 3H); 13C
NMR (100 MHz, CDCl3) δ 165.0, 147.6, 141.6, 130.7, 130.3, 127.6, 122.0, 110.0, 94.4, 52.7;
IR (ATR) ν = 3127, 2949, 1714, 1499, 1288, 1112 cm−1; HRMS (ESIꢀQTOF) m/z [M+H]+
calcd for C12H11INO2 327.9829, found 327.9844.

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Procedure for the Synthesis of 3e
To a gently refluxing mixture of 4ꢀnitroaniline (0.25 g, 0.95 mmol), and sodium acetate
(0.435 mg, 5.3 mmol) in acetic acid (2 ml) was added 2,5ꢀdimethoxytetrahydrofuran (0.13
mL, 1.04 mmol) and the reaction was continued for 3 h. Then crushed ice was added to the
reaction mixture, basified with 1 N sodium hydroxide solution, and extracted with CH2Cl2 (3
x 10 mL). The combined organic layer was dried over anhydrous MgSO4 and concentrated
under reduced pressure to afford the crude product which was purified by flash
chromatography on silica gel (hexanes: EtOAc, 95:5) to furnish 3e as a yellow solid (0.291
mg, 98.0%).
1-(2-Iodo-4-nitrophenyl)-1H-pyrrole (3e). Yellow solid, mp: 102.7ꢀ103.8 °C (291.4 mg,
98%); 1H NMR (400 MHz, CDCl3) δ 8.81 (d, J = 2.1 Hz, 1H), 8.28 (dd, J = 2.0, 8.6 Hz, 1H),
7.40 (d, J = 8.6 Hz, 1H), 6.90 (s, 2H), 6.40 (s, 2H); 13C NMR (100 MHz, CDCl3) δ 149.2,
146.7, 135.7, 127.8, 124.2, 121.9, 110.7, 93.9; HRMS (ESIꢀQTOF) m/z [M+H]+ calcd for
C10H8IN2O2 314.9625, found 314.9618.
Representative Procedure for the Synthesis of 4a
To a stirred solution of 3a (1 g, 3.72 mmol) in DMF (4 mL) at 0 °C was dropwise added
POCl3 (0.69 mL, 7.43 mmol). After being stirred at rt for 12 h the reaction mixture was
neutralized with aq. Na2CO3 solution at 0 °C. The aqueous layer was extracted with EtOAc (3
x 50 mL). The combined organic layer was washed with water (2 x 20 mL) and brine (20 mL),
dried over anhydrous MgSO4, and concentrated under reduced pressure to afford the crude
product, which was purified by flash chromatography on silica gel (hexanes: EtOAc, 9:1) to
furnish 4a as a white solid (0.766 g, 69.4%).
1-(2-Iodophenyl)-1H-pyrrole-2-carbaldehyde (4a). White solid, mp: 115.3ꢀ115.9 °C (766

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mg, 69.4%); 1H NMR (400 MHz, CDCl3) δ 9.48 (s, 1H), 7.93 (d, J = 7.9 Hz, 1H), 7.45 (t, J =
7.6 Hz, 1H), 7.34 (d, J = 7.8 Hz, 1H), 7.18 (t, J = 7.7 Hz, 1H), 7.13 (d, J = 1.6 Hz, 1H), 6.93
(s, 1H), 6.45 (s, 1H); 13C NMR (100 MHz, CDCl3) δ 178.7, 142.3, 139.6, 132.7, 130.8, 130.5,
129.1, 128.5, 122.0, 111.1, 97.7; IR (ATR) ν = 3101, 2879, 1651, 1479, 1384, 1095 cm−1;
HRMS (ESIꢀQTOF) m/z [M+H]+ calcd for C11H9INO 297.9723, found 297.9725.
1-(5-Chloro-2-iodophenyl)-1H-pyrrole-2-carbaldehyde (4b). White solid, mp: 141.9ꢀ
1
142.6 °C (792 mg, 72.5%); H NMR (400 MHz, CDCl3) δ 9.51 (s, 1H), 7.83 (d, J = 8.4 Hz,
1H), 7.33 (d, J = 2.3 Hz, 1H), 7.18 (dd, J = 2.3, 8.5 Hz, 1H), 7.11 (dd, J = 1.4, 4.0 Hz, 1H),
6.91 (s, 1H), 6.46 (dd, J = 2.8, 3.8 Hz, 1H); 13C NMR (100 MHz, CDCl3) δ 178.5, 143.6,
140.2, 134.9, 132.6, 130.71, 130.68, 128.7, 122.9, 111.4, 95.1; IR (ATR) ν = 3074, 2804,
1656, 1476, 1355, 1091 cm−1; HRMS (ESIꢀQTOF) m/z [M+H]+ calcd for C11H8ClINO
331.9334, found 331.9340.
1-(2-Iodo-4-methylphenyl)-1H-pyrrole-2-carbaldehyde (4c). White solid, mp: 73.7ꢀ
74.2 °C (1.56 g, 71.2%); 1H NMR (400 MHz, CDCl3) δ 9.46 (s, 1H), 7.75 (s, 1H), 7.19ꢀ7.25
(m, 2H), 7.11 (dd, J = 1.2, 3.8 Hz, 1H), 6.90 (s, 1H), 6.43 (t, J = 3.2 Hz, 1H), 2.39 (s, 3H);
13C NMR (100 MHz, CDCl3) δ 178.8, 140.9, 140.0, 139.7, 132.7, 130.98, 129.8, 127.98,
110.9, 97.4, 20.8; IR (ATR) ν = 3102, 2794, 1657, 1493, 1356, 1099 cm−1; HRMS (ESIꢀ
QTOF) m/z [M+H]+calcd for C12H11INO 311.9880, found 311.9882.
Methyl 4-(2-formyl-1H-pyrrol-1-yl)-3-iodobenzoate (4d). White solid, mp: 148.1ꢀ
1
148.9 °C (185 mg, 74.1%); H NMR (400 MHz, CDCl3) δ 9.51 (s, 1H), 8.58 (d, J = 1.3 Hz,

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1H), 8.10 (dd, J = 1.4, 8.1 Hz, 1H), 7.37 (d, J = 8.2 Hz, 1H), 7.13 (d, J = 2.6 Hz, 1H), 6.93 (s,
1H), 6.48 (t, J = 3.2 Hz, 1H), 3.96 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 178.5, 164.9,
146.5, 140.8, 132.6, 131.9, 130.6, 130.3, 128.3, 123.2, 111.5, 97.3, 52.8; IR (ATR) ν = 3133,
2834, 1708, 1656, 1282, 1118 cm−1; HRMS (ESIꢀQTOF) m/z [M+H]+ calcd for C13H11INO3
355.9778, found 355.9780.
1-(2-Iodo-4-nitrophenyl)-1H-pyrrole-2-carbaldehyde (4e). White solid, mp: 120.5ꢀ
1
121.8 °C (250 mg, 85.7%); H NMR (400 MHz, CDCl3) δ 9.56 (s, 1H), 8.76 (d, J = 2.2 Hz,
1H), 8.30 (dd, J = 2.3, 8.6 Hz, 1H), 7.46 (d, J = 8.6 Hz, 1H), 7.16 (d, J = 3.8 Hz, 1H), 6.94 (s,
1H), 6.52 (t, J = 3.2 Hz, 1H); 13C NMR (100 MHz, CDCl3) δ 178.5, 148.5, 147.6, 134.6,
132.5, 130.5, 128.7, 124.2, 124.1, 111.98, 97.5; IR (ATR) ν = 3111, 2841, 1663, 1517, 1340,
1097 cm−1; HRMS (ESIꢀQTOF) m/z [M+H]+ calcd for C11H8IN2O3 342.9574, found
342.9567.
Representative Procedure for the Synthesis of 5a
To a flask charged with 4a (0.12 g, 0.4 mmol), (PPh3)2PdCl2 (0.014 g, 0.02 mmol), CuI
(0.0039 g, 0.02 mmol) and phenyl acetylene (0.049 mL, 0.44 mmol) in acetonitrile (1.5 mL)
was added Et3N (0.113 mL, 0.8 mmol) at rt. After being stirred at 70 °C under nitrogen
atmosphere for 12 h, the reaction mixture was concentrated in vacuo to yield the crude
product, which was purified by flash chromatography on silica gel (hexanes: EtOAc, 9:1) to
give 5a as an off white solid (0.104 g, 95.2%).
1-(2-(Phenylethynyl)phenyl)-1H-pyrrole-2-carbaldehyde (5a). Off white solid, mp: 55.3ꢀ
1
57.2 °C (104.5 mg, 95.2%); H NMR (400 MHz, CDCl3) δ 9.54 (s, 1H), 7.63ꢀ7.66 (m, 1H),
7.43ꢀ7.47 (m, 2H), 7.37ꢀ7.41 (m, 1H), 7.28ꢀ7.29 (m, 5H), 7.20 (dd, J = 1.5, 3.9 Hz, 1H), 7.12

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(d, J = 1.9 Hz, 1H), 6.47 (dd, J = 2.7, 3.8 Hz, 1H); 13C NMR (100 MHz, CDCl3) δ 179.0,
140.4, 133.4, 132.6, 131.6, 131.2, 128.97, 128.74, 128.67, 128.4, 127.5, 126.2, 122.6, 122.1,
110.7, 94.2, 85.0; IR (ATR) ν = 3060, 2793, 1665, 1498, 1412, 1083 cm−1; HRMS (ESIꢀ
QTOF) m/z [M+H]+ calcd for C19H14NO 272.1070, found 272.1059.
1-(2-((4-Fluorophenyl)ethynyl)phenyl)-1H-pyrrole-2-carbaldehyde (5b). Colorless gum
(150.3 mg, 90.8%); 1H NMR (400 MHz, CDCl3) δ 9.53 (s, 1H), 7.60ꢀ7.64 (m, 1H), 7.42ꢀ7.47
(m, 2H), 7.38ꢀ7.41 (m, 1H), 7.21ꢀ7.27 (m, 2H), 7.18 (dd, J = 1.6, 4.0 Hz, 1H), 7.09 (t, J = 1.9
Hz, 1H), 6.97 (t, J = 8.7 Hz, 2H), 6.46 (dd, J = 2.7, 3.8 Hz, 1H); 13C NMR (100 MHz, CDCl3)
δ 179.1, 162.8 (d, J = 248.9 Hz), 140.4, 133.5 (d, J = 8.4 Hz), 133.4, 132.5, 131.2, 129.1,
128.7, 127.6, 121.9, 118.71, 118.68, 115.8 (d, J = 22.0 Hz), 110.7, 93.1, 84.7; IR (ATR) ν =
3068, 2794, 1666, 1508, 1222, 1084 cm−1; HRMS (ESIꢀQTOF) m/z [M+H]+ calcd for
C19H13FNO 290.0976, found 290.0976.
1-(2-((3-Fluorophenyl)ethynyl)phenyl)-1H-pyrrole-2-carbaldehyde (5c). Colorless gum
(133.4 mg, 91.3%); 1H NMR (400 MHz, CDCl3) δ 9.54 (s, 1H), 7.63ꢀ7.66 (m, 1H), 7.44ꢀ7.49
(m, 2H), 7.39ꢀ7.42 (m, 1H), 7.19ꢀ7.25 (m, 2H), 7.10 (s, 1H), 6.93ꢀ7.05 (m, 3H), 6.48 (t, J =
3.2 Hz, 1H); 13C NMR (100 MHz, CDCl3) δ 178.97, 162.4 (d, J = 245.1 Hz), 140.7, 133.4,
132.7, 131.3, 130.0 (d, J = 8.7 Hz), 129.4, 128.7, 127.6, 127.5 (d, J = 3.0 Hz), 124.4 (d, J =
9.3 Hz), 121.6, 121.3, 118.3 (d, J = 22.7 Hz), 116.1 (d, J = 21.2 Hz), 110.8, 92.7, 85.9; IR
(ATR) ν = 3065, 2793, 1666, 1498, 1204, 1084 cm−1; HRMS (ESIꢀQTOF) m/z [M+H]+ calcd
for C19H13FNO 290.0976, found 290.0969.

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1-(2-(m-Tolylethynyl)phenyl)-1H-pyrrole-2-carbaldehyde (5d). Colorless gum (87.3 mg,
1
75.8%); H NMR (400 MHz, CDCl3) δ 9.53 (s, 1H), 7.64 (t, J = 4.5 Hz, 1H), 7.43ꢀ7.45 (m,
2H), 7.37ꢀ7.39 (m, 1H), 7.19 (d, J = 3.0 Hz, 1H), 7.15 (d, J = 7.5 Hz, 1H), 7.06ꢀ7.11 (m, 4H),
6.46 (s, 1H), 2.30 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 178.9, 140.3, 137.98, 133.3, 132.5,
132.0, 131.2, 129.6, 128.8, 128.7, 128.6, 128.2, 127.5, 122.3, 122.0, 120.8, 110.6, 94.4, 84.6,
21.3; IR (ATR) ν = 3059, 2792, 1665, 1496, 1314, 1083 cm−1; HRMS (ESIꢀQTOF) m/z
[M+Na]+ calcd for C20H15NNaO 308.1046, found 308.1051.
1-(2-((4-Methoxyphenyl)ethynyl)phenyl)-1H-pyrrole-2-carbaldehyde (5e). Colorless gum
(80 mg, 71.7%); 1H NMR (400 MHz, CDCl3) δ 9.52 (s, 1H), 7.62 (s, 1H), 7.39ꢀ7.42 (m, 3H),
7.19ꢀ7.21 (m, 3H), 7.10 (s, 1H), 6.80 (d, J = 8.0 Hz, 2H), 6.46 (s, 1H), 3.79 (s, 3H); 13C
NMR (100 MHz, CDCl3) δ 179.1, 160.0, 140.1, 133.4, 133.1, 132.4, 131.2, 128.65, 128.58,
127.5, 122.4, 120.6, 114.7, 114.1, 110.7, 94.4, 83.8, 55.4; IR (ATR) ν = 3109, 2837, 1664,
1509, 1245, 1083 cm−1; HRMS (ESIꢀQTOF) m/z [M+Na]+ calcd for C20H15NNaO2 324.0995,
found 324.1005.
1-(2-(Thiophen-3-ylethynyl)phenyl)-1H-pyrrole-2-carbaldehyde (5f). Off white solid; mp:
1
95.0ꢀ95.8 °C (83.2 mg, 74.3%); H NMR (400 MHz, CDCl3) δ 9.53 (s, 1H), 7.62 (s, 1H),
7.39ꢀ7.44 (m, 3H), 7.32 (s, 1H), 7.18ꢀ7.22 (m, 2H), 7.10 (s, 1H), 6.96 (s, 1H), 6.45 (s, 1H);
13C NMR (100 MHz, CDCl3) δ 179.1, 140.4, 133.4, 132.4, 131.2, 129.7, 129.4, 128.9, 128.7,
127.6, 125.5, 122.0, 121.7, 120.8, 110.7, 89.5, 84.6; IR (ATR) ν = 3149, 2925, 1641, 1511,
1262, 1091 cm−1; HRMS (ESIꢀQTOF) m/z [M+H]+ calcd for C17H12NOS 278.0634, found
278.0634.

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1-(2-((6-Methoxynaphthalen-2-yl)ethynyl)phenyl)-1H-pyrrole-2-carbaldehyde (5g). Off
white solid; mp: 98.1ꢀ98.8 °C (90.3 mg, 63.6%); 1H NMR (400 MHz, CDCl3) δ 9.56 (s, 1H),
7.61ꢀ7.72 (m, 4H), 7.40ꢀ7.47 (m, 3H), 7.22ꢀ7.24 (m, 2H), 7.13ꢀ7.15 (m, 2H), 7.08 (s, 1H),
6.50 (s, 1H), 3.92 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 179.1, 158.5, 140.3, 134.4, 133.4,
132.5, 131.5, 131.3, 129.5, 128.8, 128.7, 128.6, 128.4, 127.5, 126.9, 122.2, 120.8, 119.5,
117.4, 110.7, 105.9, 94.9, 84.7, 55.4; IR (ATR) ν = 3148, 2919, 1643, 1429, 1262, 1113 cm−1;
HRMS (ESIꢀQTOF) m/z [M+H]+ calcd for C24H18NO2 352.1332, found 352.1336.
1-(2-(Cyclohexenylethynyl)phenyl)-1H-pyrrole-2-carbaldehyde(5h). Colorless oil (132
mg, 95%); 1H NMR (400 MHz, CDCl3) δ 9.47 (s, 1H), 7.51ꢀ7.54 (m, 1H), 7.37ꢀ7.40 (m, 2H),
7.32ꢀ7.34 (m, 1H), 7.14ꢀ7.15 (m, 1H), 7.04 (s, 1H), 6.41 (t, J = 3.1 Hz, 1H), 5.99 (s, 1H),
2.05ꢀ2.06 (m, 2H), 1.97 (br s, 2H), 1.54 (br s, 2H), 1.59 (br s, 2H); 13C NMR (100 MHz,
CDCl3) δ 179.1, 140.0, 136.3, 133.2, 132.4, 130.96, 128.5, 128.4, 127.4, 122.5, 120.4, 110.6,
96.3, 82.4, 28.6, 25.8, 22.2, 21.4; IR (ATR) ν = 3112, 2927, 1665, 1494, 1333, 1082 cm−1;
HRMS (ESIꢀQTOF) m/z [M+H]+ calcd for C19H18NO 276.1383, found 276.1383.
1-(2-(Cyclopentylethynyl)phenyl)-1H-pyrrole-2-carbaldehyde (5i). Colorless oil (82.3 mg,
1
77.4%); H NMR (400 MHz, CDCl3) δ 9.45 (s, 1H), 7.49 (t, J = 4.6 Hz, 1H), 7.36ꢀ7.38 (m,
2H), 7.30ꢀ7.32 (m, 1H), 7.13 (d, J = 3.9 Hz, 1H), 7.01 (s, 1H), 7.39 (d, J = 2.6 Hz, 1H), 2.62ꢀ
2.65 (m, 1H), 1.75ꢀ1.79 (m, 2H), 1.60 (br s, 2H), 1.45ꢀ1.47 (m, 4H); 13C NMR (100 MHz,
CDCl3) δ 179.1, 140.3, 133.2, 132.6, 130.7, 128.5, 128.1, 127.3, 122.9, 120.0, 110.5, 100.2,
75.6, 33.5, 30.7, 24.9; IR (ATR) ν = 2957, 2868, 1664, 1494, 1333, 1085 cm−1; HRMS (ESIꢀ

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QTOF) m/z [M+H]+ calcd for C18H18NO 264.1383, found 264.1388.
1-(2-(Hex-1-ynyl)phenyl)-1H-pyrrole-2-carbaldehyde (5j). Colorless oil (78.5 mg, 77.3%);
1H NMR (400 MHz, CDCl3) δ 9.46 (s, 1H), 7.50ꢀ7.52 (m, 1H), 7.36ꢀ7.38 (m, 2H), 7.29ꢀ7.31
(m, 1H), 7.12ꢀ7.13 (m, 1H), 7.03 (s, 1H), 7.40 (t, J = 3.1 Hz, 1H), 2.22 (t, J = 6.9 Hz, 2H),
1.35ꢀ1.38 (m, 2H), 1.22ꢀ1.28 (m, 2H), 0.84 (t, J = 7.3 Hz, 3H); 13C NMR (100 MHz, CDCl3)
δ 179.1, 140.2, 133.2, 132.8, 130.8, 128.5, 128.2, 127.4, 122.7, 120.2, 110.5, 95.9, 76.1, 30.3,
21.8, 19.1, 13.6; IR (ATR) ν = 2932, 2862, 1665, 1494, 1333, 1085 cm−1; HRMS (ESIꢀ
QTOF) m/z [M+H]+ calcd for C17H18NO 252.1383, found 252.1398.
1-(5-Chloro-2-(phenylethynyl)phenyl)-1H-pyrrole-2-carbaldehyde (5k). Off white solid,
mp: 130.0ꢀ130.8 °C (99.9 mg, 90.3%); 1H NMR (400 MHz, CDCl3) δ 9.56 (s, 1H), 7.56 (d, J
= 8.2 Hz, 1H), 7.40ꢀ7.43 (m, 2H), 7.23ꢀ7.30 (m, 5H), 7.17ꢀ7.18 (m, 1H), 7.08 (s, 1H), 6.47 (t,
J = 3.1 Hz, 1H); 13C NMR (100 MHz, CDCl3) δ 178.7, 141.6, 134.4, 133.3, 131.6, 131.2,
129.0, 128.9, 128.4, 127.8, 122.4, 122.1, 120.7, 111.0, 94.96, 84.2; IR (ATR) ν = 3061, 2790,
1656, 1387, 1525, 1093 cm−1; HRMS (ESIꢀQTOF) m/z [M+H]+ calcd for C19H13ClNO
306.0680, found 306.0674.
1-(5-Chloro-2-((4-fluorophenyl)ethynyl)phenyl)-1H-pyrrole-2-carbaldehyde (5l). Off
1
white solid; mp: 139.9ꢀ142.2 °C (100.7 mg, 86.2%); H NMR (400 MHz, CDCl3) δ 9.55 (s,
1H), 7.54 (d, J = 8.2 Hz, 1H), 7.40ꢀ7.43 (m, 2H), 7.20ꢀ7.24 (m, 2H), 7.17 (dd, J = 1.2, 3.8 Hz,
1H), 7.08 (s, 1H), 6.97 (t, J = 8.7 Hz, 2H), 6.47 (t, J = 3.2 Hz, 1H); 13C NMR (100 MHz,
CDCl3) δ 178.7, 162.9 (d, J = 249.0 Hz), 141.5, 134.5, 133.6 (d, J = 8.4 Hz), 133.3, 133.2,

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131.2, 129.0, 127.9, 122.0, 120.5, 118.5 (d, J = 3.5 Hz), 115.8 (d, J = 22.1 Hz), 111.1, 93.9,
83.9; IR (ATR) ν = 2864, 2793, 1653, 1508, 1386, 1092 cm−1; HRMS (ESIꢀQTOF) m/z
[M+H]+ calcd for C19H12ClFNO 324.0586, found 324.0592.
1-(5-Chloro-2-((4-methoxyphenyl)ethynyl)phenyl)-1H-pyrrole-2-carbaldehyde (5m). Off
1
white solid; mp: 120.4ꢀ121.1 °C (84.3 mg, 83.2%); H NMR (400 MHz, CDCl3) δ 9.55 (s,
1H), 7.53 (d, J = 8.2 Hz, 1H), 7.39ꢀ7.42 (m, 2H), 7.16ꢀ7.19 (m, 3H), 7.08 (s, 1H), 6.80 (d, J =
8.8 Hz, 2H), 6.46 (dd, J = 2.8, 3.8 Hz, 1H), 3.79 (s, 3H); 13C NMR (100 MHz, CDCl3) δ
178.8, 160.2, 141.3, 133.98, 133.3, 133.1, 133.0, 131.2, 128.96, 127.8, 121.1, 114.4, 114.1,
110.98, 95.3, 83.0, 55.4; IR (ATR) ν = 3061, 2837, 1654, 1511, 1243, 1075 cm−1; HRMS
(ESIꢀQTOF) m/z [M+H]+ calcd for C20H15ClNO2 336.0781, found 336.0789.
1-(5-Chloro-2-(thiophen-3-ylethynyl)phenyl)-1H-pyrrole-2-carbaldehyde (5n). Brown
1
solid; mp: 107.8ꢀ108.7 °C (65.3 mg, 69.4%); H NMR (400 MHz, CDCl3) δ 9.55 (s, 1H),
7.53 (d, J = 8.3 Hz, 1H), 7.39ꢀ7.42 (m, 2H), 7.31 (s, 1H), 7.23 (d, J = 4.6 Hz, 1H), 7.16 (s,
1H), 7.07 (s, 1H), 6.94 (d, J = 4.6 Hz, 1H), 6.46 (s, 1H); 13C NMR (100 MHz, CDCl3) δ
178.7, 141.4, 134.3, 133.2, 133.1, 131.1, 129.59, 129.56, 128.9, 127.8, 125.6, 121.9, 121.4,
120.6, 111.0, 90.3, 83.8; IR (ATR) ν = 3099, 2862, 1653, 1524, 1386, 1075 cm−1; HRMS
(ESIꢀQTOF) m/z [M+H]+ calcd for C17H11ClNOS 312.0244, found 312.0248.
1-(5-Chloro-2-(cyclohexenylethynyl)phenyl)-1H-pyrrole-2-carbaldehyde (5o). Yellow oil
(80.7 mg, 72%); 1H NMR (400 MHz, CDCl3) δ 9.50 (s, 1H), 7.44 (d, J = 8.2 Hz, 1H), 7.34ꢀ
7.37 (m, 2H), 7.12ꢀ7.13 (m, 1H), 7.01 (s, 1H), 6.42 (t, J = 3.2 Hz, 1H), 5.98 (s, 1H), 2.06 (brs,

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2H), 1.96 (brs, 2H), 1.56 (brs, 2H), 1.53 (brs, 2H); 13C NMR (100 MHz, CDCl3) δ 178.8,
141.1, 136.7, 133.7, 133.2, 130.9, 128.9, 127.7, 121.5, 121.2, 120.3, 110.9, 97.1, 81.6, 28.6,
25.9, 22.2, 21.4; IR (ATR) ν = 3110, 2927, 1665, 1490, 1362, 1096 cm−1; HRMS (ESIꢀ
QTOF) m/z [M+Na]+ calcd for C19H16ClNNaO 332.0813, found 332.0812.
1-(4-Methyl-2-(phenylethynyl)phenyl)-1H-pyrrole-2-carbaldehyde (5p). Brown solid, mp:
1
115.9ꢀ116.7 °C (84.6 mg, 92.2%); H NMR (400 MHz, CDCl3) δ 9.52 (s, 1H), 7.46 (s, 1H),
7.23ꢀ7.27 (m, 7H), 7.17 (d, J = 2.6 Hz, 1H), 7.08 (s, 1H), 6.44 (t, J = 3.1 Hz, 1H), 2.43 (s,
3H); 13C NMR (100 MHz, CDCl3) δ 179.1, 138.7, 137.9, 133.4, 133.0, 131.6, 131.3, 129.8,
128.6, 128.4, 127.3, 122.7, 121.7, 120.7, 110.6, 93.8, 85.1, 21.1; IR (ATR) ν = 3103, 2975,
1653, 1504, 1389, 1188 cm−1; HRMS (ESIꢀQTOF) m/z [M+H]+ calcd for C20H16NO
286.1226, found 286.1231.
1-(2-((4-Fluorophenyl)ethynyl)-4-methylphenyl)-1H-pyrrole-2-carbaldehyde (5q). Off
1
white solid; mp: 90.7ꢀ91.9 °C (95.9 mg, 82%); H NMR (400 MHz, CDCl3) δ 9.51 (s, 1H),
7.44 (s, 1H), 7.17ꢀ7.25 (m, 5H), 7.06 (s, 1H), 6.96 (t, J = 7.9 Hz, 2H), 6.44 (s, 1H), 2.42 (s,
3H); 13C NMR (100 MHz, CDCl3) δ 179.1, 162.7 (d, J = 248.7 Hz), 138.8, 137.9, 133.5 (d, J
= 8.4 Hz), 133.4, 132.9, 131.3, 129.9, 127.3, 121.5, 120.6, 118.8, 115.7 (d, J = 22.0 Hz),
110.6, 92.7, 84.9, 21.1; IR (ATR) ν = 3109, 2793, 1660, 1508, 1224, 1083 cm−1; HRMS
(ESIꢀQTOF) m/z [M+H]+ calcd for C20H15FNO 304.1132, found 304.1150.
1-(2-((4-Methoxyphenyl)ethynyl)-4-methylphenyl)-1H-pyrrole-2-carbaldehyde (5r). Off
white solid; mp: 86.9ꢀ87.8 °C (101.7 mg, 83.6%); 1H NMR (400 MHz, CDCl3) δ 9.51 (s, 1H),

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7.43 (s, 1H), 7.25 (s, 1H), 7.17ꢀ7.22 (m, 4H), 7.08 (s, 1H), 7.79 (d, J = 8.4 Hz, 2H), 6.44 (s,
1H), 3.79 (s, 3H), 2.42 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 179.2, 159.9, 138.7, 137.6,
133.4, 133.1, 132.8, 131.2, 129.4, 127.2, 122.0, 120.4, 114.8, 114.0, 110.5, 94.0, 83.9, 55.4,
21.1; IR (ATR) ν = 3098, 2870, 1663, 1512, 1387, 1027 cm−1; HRMS (ESIꢀQTOF) m/z
[M+Na]+ calcd for C21H17NNaO2 338.1151, found 338.1142.
1-(4-Methyl-2-(thiophen-3-ylethynyl)phenyl)-1H-pyrrole-2-carbaldehyde (5s). Brown
1
solid; mp: 113.9ꢀ114.6 °C (100.6 mg, 89.5%); H NMR (400 MHz, CDCl3) δ 9.52 (s, 1H),
7.44 (s, 1H), 7.31 (d, J = 2.6 Hz, 1H), 7.21ꢀ7.28 (m, 3H), 7.16ꢀ7.17 (m, 1H), 7.07 (s, 1H),
6.95 (d, J = 4.9 Hz, 1H), 6.43 (t, J = 3.2 Hz, 1H), 2.43 (s, 3H); 13C NMR (100 MHz, CDCl3)
δ 179.2, 138.7, 137.9, 133.4, 132.9, 131.3, 129.72, 129.70, 129.2, 127.3, 125.5, 121.8, 121.6,
120.4, 110.6, 89.1, 84.8, 21.2; IR (ATR) ν = 3111, 2861, 1649, 1526, 1332, 1087 cm−1;
HRMS (ESIꢀQTOF) m/z [M+H]+ calcd for C18H14NOS 292.0791, found 292.0798.
1-(2-(Cyclohexenylethynyl)-4-methylphenyl)-1H-pyrrole-2-carbaldehyde (5t). Colorless
oil (95.1 mg, 85.2%); 1H NMR (400 MHz, CDCl3) δ 9.46 (s, 1H), 7.34 (s, 1H), 7.16ꢀ7.25 (m,
2H), 7.13 (dd, J = 1.4, 3.9 Hz, 1H), 7.01 (d, J = 1.6 Hz, 1H), 6.39 (dd, J = 2.7, 3.8 Hz, 1H),
5.96ꢀ5.98 (m, 1H), 2.39 (s, 3H), 2.05ꢀ2.06 (m, 2H), 1.96ꢀ1.97 (m, 2H), 1.53ꢀ1.56 (m, 4H);
13C NMR (100 MHz, CDCl3) δ 179.2, 139.96, 138.6, 136.1, 133.3, 132.9, 131.0, 129.8,
129.2, 127.2, 122.1, 120.4, 110.4, 95.9, 82.5, 28.6, 25.8, 22.2, 21.5, 21.1; IR (ATR) ν = 3111,
2925, 1667, 1502, 1333, 1081 cm−1; HRMS (ESIꢀQTOF) m/z [M+H]+ calcd for C20H20NO
290.1539, found 290.1547.

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Methyl 4-(2-formyl-1H-pyrrol-1-yl)-3-(phenylethynyl)benzoate (5u). Off white solid, mp:
1
81.6ꢀ82.9 °C (85 mg, 83.3%); H NMR (400 MHz, CDCl3) δ 9.56 (s, 1H), 8.32 (s, 1H), 8.09
(d, J = 8.2 Hz, 1H), 7.44 (d, J = 8.3 Hz, 1H), 7.29ꢀ7.30 (m, 5H), 7.19 (d, J = 2.8 Hz, 1H),
7.14 (s, 1H), 6.49 (t, J = 3.0 Hz, 1H), 3.97 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 178.7,
165.7, 144.1, 134.0, 133.2, 131.7, 131.3, 130.4, 129.9, 129.0, 128.5, 127.6, 122.4, 122.3,
122.2, 111.1, 94.9, 84.4, 52.7; IR (ATR) ν = 3121, 2870, 1723, 1656, 1429, 1250, 1107 cm−1;
HRMS (ESIꢀQTOF) m/z [M+H]+ calcd for C21H16NO3 330.1125, found 330.1135.
Methyl 4-(2-formyl-1H-pyrrol-1-yl)-3-((4-methoxyphenyl)ethynyl)benzoate (5v). Off
white solid; mp: 138.0ꢀ138.9 °C (90 mg, 85.7%); 1H NMR (400 MHz, CDCl3) δ 9.55 (s, 1H),
8.29 (s, 1H), 8.06 (d, J = 8.2 Hz, 1H), 7.43 (d, J = 8.2 Hz, 1H), 7.19ꢀ7.23 (m, 3H), 7.13 (s,
1H), 6.81 (d, J = 8.5 Hz, 2H), 6.48 (s, 1H), 3.97(s, 3H), 3.80 (s, 3H); 13C NMR (100 MHz,
CDCl3) δ 178.7, 165.8, 160.2, 143.8, 133.7, 133.2, 131.2, 130.3, 129.5, 127.5, 122.5, 122.1,
114.3, 114.1, 111.0, 95.2, 83.2, 55.4, 52.6; IR (ATR) ν = 3001, 2836, 1713, 1660, 1513, 1244,
1100 cm−1; HRMS (ESIꢀQTOF) m/z [M+H]+ calcd for C22H18NO4 360.1230, found 360.1237.
1-(4-Nitro-2-(phenylethynyl)phenyl)-1H-pyrrole-2-carbaldehyde (5w). Brown solid, mp:
1
165.5ꢀ166.7 °C (91.2 mg, 82.2%); H NMR (400 MHz, CDCl3) δ 9.59 (s, 1H), 8.48 (s, 1H),
8.26 (d, J = 7.6 Hz, 1H), 7.53 (d, J = 8.2 Hz, 1H), 7.26ꢀ7.30 (m, 5H), 7.21 (s, 1H), 7.17 (s,
1H), 6.54 (s, 1H); 13C NMR (100 MHz, CDCl3) δ 178.5, 147.3, 145.8, 133.1, 131.8, 131.4,
129.5, 128.6, 128.5, 127.6, 124.1, 123.5, 123.3, 121.7, 111.5, 96.4, 83.4; IR (ATR) ν = 3080,
2843, 1657, 1519, 1342, 1071 cm−1; HRMS (ESIꢀQTOF) m/z [M+H]+ calcd for C19H13N2O3
317.0921, found 317.0915.

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1-(4-Nitro-2-(m-tolylethynyl)phenyl)-1H-pyrrole-2-carbaldehyde (5x). Yellow solid; mp:
143.2ꢀ144.8 °C (77.2 mg, 80%); 1H NMR (400 MHz, CDCl3) δ 9.59 (s, 1H), 8.48 (d, J = 2.5
Hz, 1H), 8.26 (dd, J = 2.5, 8.7 Hz, 1H), 7.52 (d, J = 8.7 Hz, 1H), 7.17ꢀ7.22 (m, 4H), 7.08ꢀ
7.12 (m, 2H), 6.53 (t, J = 3.3 Hz, 1H), 2.32 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 178.5,
147.2, 145.7, 138.3, 133.1, 132.3, 131.4, 130.4, 128.9, 128.48, 128.46, 127.7, 124.1, 123.4,
121.5, 111.5, 96.7, 83.0, 21.3; IR (ATR) ν = 3082, 2829, 1668, 1518, 1343, 1093 cm−1;
HRMS (ESIꢀQTOF) m/z [M+H]+ calcd for C20H15N2O3 331.1077, found 331.1086.
Representative Procedure for the Synthesis of 6
Condition A: In a vial containing 5a (27 mg, 0.1 mmol) was added TFA (0.5 mL) and the
resulting solution was stirred at 90 °C for 1 h. The reaction mixture was cooled down to rt
and concentrated in vacuo to yield the crude product. Purification by flash chromatography
on silica gel (hexanes: EtOAc, 95:5) gave 6a as a yellow solid (26.7 mg, 99%).
Condition B: In a vial containing 5d (30 mg, 0.105 mmol) was added DCE (0.5 mL) and
TFA (0.5 mL) and the resulting solution was stirred at 90 °C for 1 h. The reaction mixture
was cooled down to rt and concentrated in vacuo to yield the crude product. Purification by
flash chromatography on silica gel (hexanes: EtOAc, 95:5) gave 6d as a yellow solid (24.6
mg, 82%).
Phenyl(pyrrolo[1,2-a]quinolin-5-yl)methanone (6a). Yellow solid, mp: 94.4ꢀ95.2 °C (26.7
1
mg, 99%); H NMR (400 MHz, CDCl3) δ 8.36 (d, J = 8.1 Hz, 1H), 7.95ꢀ7.99 (m, 2H), 7.91
(d, J = 7.3 Hz, 2H), 7.56ꢀ7.63 (m, 3H), 7.50 (t, J = 7.6 Hz, 2H), 7.38 (t, J = 7.5 Hz, 1H), 6.88
(t, J = 3.3 Hz, 1H), 6.73 (d, J = 3.2 Hz, 1H); 13C NMR (100 MHz, CDCl3) δ 196.3, 139.0,
133.2, 132.8, 130.3, 128.7, 128.61, 128.58, 127.9, 125.9, 125.2, 124.4, 121.5, 114.7, 114.5,

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114.3, 107.9; IR (ATR) ν = 3060, 2925, 1639, 1593, 1260, 1229, 1083 cm−1; HRMS (ESIꢀ
QTOF) m/z [M+H]+ calcd for C19H14NO 272.1070, found 272.1069.
(4-Fluorophenyl)(pyrrolo[1,2-a]quinolin-5-yl)methanone (6b). Yellow solid; mp: 124.8ꢀ
1
125.9 °C (55.6 mg, 92.7%); H NMR (400 MHz, CDCl3) δ 8.29 (dd, J = 0.9, 8.2 Hz, 1H),
7.93ꢀ7.99 (m, 4H), 7.55ꢀ7.59 (m, 2H), 7.36ꢀ7.40 (m, 1H), 7.17 (t, J = 8.6 Hz, 2H), 6.88 (dd, J
= 3.0, 3.7 Hz, 1H), 6.74 (dd, J = 1.0, 3.8 Hz, 1H); 13C NMR (100 MHz, CDCl3) δ 194.7,
165.7 (d, J = 253.0 Hz), 135.2 (d, J = 3.0 Hz), 133.2, 132.8 (d, J = 9.1 Hz), 128.7, 128.6,
127.7, 125.7, 124.7, 124.4, 121.3, 115.8, 115.6, 114.7, 114.5 (d, J = 16.7 Hz), 107.9; IR (ATR)
ν = 3067, 2892, 1638, 1592, 1449, 1092 cm−1; HRMS (ESIꢀQTOF) m/z [M+H]+ calcd for
C19H13FNO 290.0976, found 290.0982.
(3-Fluorophenyl)(pyrrolo[1,2-a]quinolin-5-yl)methanone (6c). Yellow solid; mp: 126.7ꢀ
1
128.2 °C (41.4 mg, 82.8%); H NMR (400 MHz, CDCl3) δ 8.38 (d, J = 8.2 Hz, 1H), 8.00 (s,
1H), 7.96 (d, J = 8.4 Hz, 1H), 7.66 (d, J = 7.7 Hz, 1H), 7.57ꢀ7.61 (m, 3H), 7.44ꢀ7.50 (m, 1H),
7.40 (t, J = 7.7 Hz, 1H), 7.31 (dt, J = 1.8, 8.3 Hz, 1H), 6.89 (t, J = 3.3 Hz, 1H), 6.77 (d, J =
3.6 Hz, 1H); 13C NMR (100 MHz, CDCl3) δ 194.7, 162.7 (d, J = 247.0 Hz), 141.2, 133.2,
130.2 (d, J = 7.7 Hz), 128.7, 128.6, 127.8, 126.0 (d, J = 3.0 Hz), 125.6, 125.1, 124.5, 121.2,
119.7 (d, J = 21.3 Hz), 116.9 (d, J = 22.1 Hz), 115.0, 114.6, 114.5, 108.5; IR (ATR) ν = 2948,
2835, 1649, 1450, 1265, 1114 cm−1; HRMS (ESIꢀQTOF) m/z [M+H]+ calcd for C19H13FNO
290.0976, found 290.0975.
Pyrrolo[1,2-a]quinolin-5-yl(m-tolyl)methanone (6d). Yellow solid; mp: 107.9ꢀ108.6 °C

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(24.6 mg, 82%); 1H NMR (400 MHz, CDCl3) δ 8.35 (d, J = 8.2 Hz, 1H), 7.95ꢀ7.99 (m, 2H),
7.74 (s, 1H), 7.68 (d, J = 7.4 Hz, 1H), 7.56ꢀ7.60 (m, 2H), 7.36ꢀ7.44 (m, 3H), 6.88 (t, J = 3.0
Hz, 1H), 6.73 (d, J = 3.5 Hz, 1H), 2.43 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 196.5, 139.0,
138.4, 133.6, 133.2, 130.6, 128.7, 128.6, 128.4, 127.8, 127.6, 126.1, 124.98, 124.4, 121.5,
114.6, 114.5, 114.3, 107.8, 21.5; IR (ATR) ν = 3137, 2921, 1634, 1448, 1267, 1095 cm−1;
HRMS (ESIꢀQTOF) m/z [M+H]+ calcd for C20H16NO 286.1226, found 286.1236.
(4-Methoxyphenyl)(pyrrolo[1,2-a]quinolin-5-yl)methanone (6e). Yellow gum (25.2 mg,
84%); 1H NMR (400 MHz, CDCl3) δ 8.18 (dd, J = 0.8, 8.2 Hz, 1H), 7.91ꢀ7.97 (m, 4H), 7.54ꢀ
7.58 (m, 2H), 7.33ꢀ7.37 (m, 1H), 6.97 (d, J = 8.8 Hz, 2H), 6.87 (dd, J = 3.0, 3.6 Hz, 1H), 6.71
(dd, J = 1.0, 3.8 Hz, 1H), 3.90 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 195.0, 163.7, 133.2,
132.7, 131.4, 128.9, 128.5, 127.8, 126.6, 124.2, 123.5, 121.6, 114.5, 114.3, 114.1, 113.8,
107.1, 55.7; IR (ATR) ν = 3002, 2837, 1638, 1592, 1252, 1093 cm−1; HRMS (ESIꢀQTOF)
m/z [M+H]+ calcd for C20H16NO2 302.1176, found 302.1184.
Pyrrolo[1,2-a]quinolin-5-yl(thiophen-3-yl)methanone (6f). Yellow solid; mp: 119.2ꢀ
120.9 °C (32.4 mg, 81%); 1H NMR (400 MHz, CDCl3) δ 8.32 (d, J = 8.2 Hz, 1H), 7.93ꢀ7.97
(m, 3H), 7.74 (s, 1H), 7.66 (d, J = 5.0 Hz, 1H), 7.56 (t, J = 7.7 Hz, 1H), 7.35ꢀ7.41 (m, 2H),
6.88 (t, J = 3.3 Hz, 1H), 6.75 (d, J = 3.6 Hz, 1H); 13C NMR (100 MHz, CDCl3) δ 189.4,
142.96, 134.1, 133.2, 128.7, 128.6, 127.6, 126.8, 126.5, 124.3, 123.9, 121.1, 114.6, 114.5,
114.3, 107.7; IR (ATR) ν = 3137, 2892, 1634, 1447, 1262, 1160 cm−1; HRMS (ESIꢀQTOF)
m/z [M+H]+ calcd for C17H12NOS 278.0634, found 278.0629.

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(6-Methoxynaphthalen-2-yl)(pyrrolo[1,2-a]quinolin-5-yl)methanone (6g). Yellow solid;
1
mp: 185.8ꢀ186.4 °C (34.8, 87%); H NMR (400 MHz, CDCl3) δ 8.28ꢀ8.31 (m, 2H), 8.05 (d,
J = 8.4 Hz, 1H), 7.96ꢀ7.99 (m, 2H), 7.84 (d, J = 8.6 Hz, 1H), 7.78 (d, J = 9.6 Hz, 1H), 7.65 (s,
1H), 7.58 (t, J = 7.7 Hz, 1H), 7.37 (t, J = 7.6 Hz, 1H), 7.19ꢀ7.21 (m, 2H), 6.89 (t, J = 3.0 Hz,
1H), 6.72 (d, J = 3.3 Hz, 1H), 3.97 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 196.0, 159.9,
137.3, 134.0, 133.2, 132.1, 131.2, 128.8, 128.6, 127.8, 127.3, 126.5, 124.3, 124.2, 121.6,
119.8, 114.5, 114.4, 114.2, 107.5, 105.9, 55.6; IR (ATR) ν = 3062, 2848, 1648, 1616, 1271,
1093 cm−1; HRMS (ESIꢀQTOF) m/z [M+H]+ calcd for C24H18NO2 352.1332, found 352.1336.
Cyclohexenyl(pyrrolo[1,2-a]quinolin-5-yl)methanone (6h). Yellow gum (9.8 mg, 32.6%);
1H NMR (400 MHz, CDCl3) δ 7.99 (d, J = 8.1 Hz, 1H), 7.91ꢀ7.92 (m, 2H), 7.53 (t, J = 7.2
Hz, 1H), 7.45 (s, 1H), 7.33 (t, J = 7.5 Hz, 1H), 6.84 (t, J = 3.2 Hz, 1H), 6.77 (s, 1H), 6.68 (d,
J = 2.8 Hz, 1H), 2.50 (br s, 2H), 2.25 (br s, 2H), 1.77ꢀ1.79 (m, 2H), 1.68ꢀ1.71 (m, 2H); 13C
NMR (100 MHz, CDCl3) δ 197.8, 144.8, 140.5, 133.3, 129.0, 128.4, 127.5, 127.2, 124.1,
121.8, 121.7, 114.5, 113.9, 113.7, 106.2, 26.4, 23.8, 22.2, 21.8; IR (ATR) ν = 2928, 2857,
1626, 1553, 1449, 1092 cm−1; HRMS (ESIꢀQTOF) m/z [M+H]+ calcd for C19H18NO
276.1383, found 276.1392.
(8-Chloropyrrolo[1,2-a]quinolin-5-yl)(phenyl)methanone (6i). Yellow solid, mp: 158.7ꢀ
1
159.8 °C (33.4 mg, 83.5%); H NMR (400 MHz, CDCl3) δ 8.34 (d, J = 8.8 Hz, 1H), 7.87ꢀ
7.94 (m, 4H), 7.60ꢀ7.62 (m, 2H), 7.50 (t, J = 7.2 Hz, 2H), 7.34 (d, J = 8.6 Hz, 1H), 6.89 (s,
1H), 6.75 (s, 1H); 13C NMR (100 MHz, CDCl3) δ 195.9, 138.8, 134.3, 133.9, 132.9, 130.2,
129.2, 128.8, 128.6, 125.6, 125.1, 124.8, 119.96, 115.0. 114.9, 114.6, 108.6; IR (ATR) ν =

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3144, 3036, 1636, 1590, 1423, 1096 cm−1; HRMS (ESIꢀQTOF) m/z [M+H]+ calcd for
C19H13ClNO 306.0680, found 306.0684.
(8-Chloropyrrolo[1,2-a]quinolin-5-yl)(4-fluorophenyl)methanone (6j). Yellow solid; mp:
1
194.0ꢀ195.2 °C (30.8 mg, 77%); H NMR (400 MHz, CDCl3) δ 8.28 (d, J = 8.8 Hz, 1H),
7.90ꢀ7.94 (m, 4H), 7.57 (s, 1H), 7.34 (d, J = 8.8 Hz, 1H), 7.18 (t, J = 8.5 Hz, 2H), 6.90 (t, J =
3.3 Hz, 1H), 6.76 (d, J = 3.8 Hz, 1H); 13C NMR (100 MHz, CDCl3) δ 194.3, 165.7 (d, J =
253.3 Hz), 135.0 (d, J = 2.9 Hz), 134.4, 133.9, 132.8 (d, J = 9.2 Hz), 129.1, 128.7, 125.1,
125.0, 124.8, 119.8, 115.8 (d, J = 21.8 Hz), 115.1, 115.0, 114.7, 108.6; IR (ATR) ν = 3069,
2983, 1644, 1593, 1230, 1096 cm−1; HRMS (ESIꢀQTOF) m/z [M+H]+ calcd for
C19H12ClFNO 324.0586, found 324.0585.
(8-Chloropyrrolo[1,2-a]quinolin-5-yl)(4-methoxyphenyl)methanone (6k). Yellow solid;
mp: 180.4ꢀ182.1 °C (17.2 mg, 86%); 1H NMR (400 MHz, CDCl3) δ 8.16 (d, J = 8.8 Hz, 1H),
7.89ꢀ7.93 (m, 4H), 7.55 (s, 1H), 7.31 (dd, J = 1.8, 8.9 Hz, 1H), 6.97 (d, J = 8.8 Hz, 2H), 6.88
(t, J = 3.3 Hz, 1H), 6.72 (d, J = 3.4 Hz, 1H), 3.90 (s, 3H); 13C NMR (100 MHz, CDCl3) δ
194.6, 163.7, 134.2, 133.97, 132.6, 131.2, 129.2, 128.98, 125.9, 124.6, 123.9, 120.1, 114.7,
114.6, 114.5, 113.9, 107.8, 55.7; IR (ATR) ν = 2920, 2845, 1635, 1599, 1251, 1097 cm−1;
HRMS (ESIꢀQTOF) m/z [M+Na]+ calcd for C20H14ClNNaO2 358.0605, found 358.0602.
(8-Chloropyrrolo[1,2-a]quinolin-5-yl)(thiophen-3-yl)methanone (6l). Yellow solid; mp:
1
178.9ꢀ179.8 °C (25.2 mg, 84%); H NMR (400 MHz, CDCl3) δ 8.29 (d, J = 8.8 Hz, 1H),
7.97 (d, J = 1.8 Hz, 1H), 7.91 (dd, J = 1.7, 9.0 Hz, 2H), 7.75 (s, 1H), 7.65 (d, J = 5.0 Hz, 1H),

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7.41 (dd, J = 3.0, 5.0 Hz, 1H), 7.32 (dd, J = 1.8, 8.8 Hz, 1H), 6.89 (t, J = 3.3 Hz, 1H), 6.77 (d,
J = 3.6 Hz, 1H); 13C NMR (100 MHz, CDCl3) δ 189.1, 142.7, 134.4, 134.1, 133.9, 129.1,
128.8, 128.6, 126.7, 126.1, 124.7, 124.2, 119.6, 114.9, 114.6, 108.3; IR (ATR) ν = 3112, 2917,
1629, 1430, 1265, 1093 cm−1; HRMS (ESIꢀQTOF) m/z [M+H]+ calcd for C17H11ClNOS
312.0244, found 312.0249.
(8-Chloropyrrolo[1,2-a]quinolin-5-yl)(cyclohexenyl)methanone (6m). Yellow solid; mp:
1
166.1ꢀ167.2 °C (10.4 mg, 34.6%); H NMR (400 MHz, CDCl3) δ 7.96 (d, J = 8.4 Hz, 1H),
7.89 (s, 1H), 7.84 (s, 1H), 7.46 (s, 1H), 7.29 (d, J = 8.8 Hz, 1H), 6.86 (s, 1H), 6.75 (s, 1H),
6.70 (d, J = 3.6 Hz, 1H), 2.48 (br s, 2H), 2.26 (br s, 2H), 1.76ꢀ1.77 (m, 2H), 1.69ꢀ1.70 (m,
2H); 13C NMR (100 MHz, CDCl3) δ 197.4, 144.9, 140.4, 134.1, 134.0, 129.1, 128.9, 126.4,
124.5, 122.2, 120.2, 114.6, 114.5, 114.0, 106.9, 26.4, 23.8, 22.1, 21.8; IR (ATR) ν = 3107,
2796, 1650, 1524, 1385, 1075 cm−1; HRMS (ESIꢀQTOF) m/z [M+H]+ calcd for C19H17ClNO
310.0993, found 310.0997.
(7-Methylpyrrolo[1,2-a]quinolin-5-yl)(phenyl)methanone (6n). Yellow gum (34.5 mg,
1
86.2%); H NMR (400 MHz, CDCl3) δ 8.17 (s, 1H), 7.95 (s, 1H), 7.91 (d, J = 7.4 Hz, 2H),
7.85 (d, J = 8.5 Hz, 1H), 7.61 (t, J = 7.3 Hz, 1H), 7.56 (s, 1H), 7.50 (t, J = 7.6 Hz, 2H), 7.39
(d, J = 8.5 Hz, 1H), 6.85 (t, J = 3.3 Hz, 1H), 6.70 (d, J = 3.6 Hz, 1H), 2.45 (s, 3H); 13C NMR
(100 MHz, CDCl3) δ 196.8, 138.9, 134.1, 132.9, 131.3, 130.4, 129.8, 128.6, 128.5, 127.5,
125.6, 125.4, 121.3, 114.6, 114.4, 114.1, 107.8, 21.4; IR (ATR) ν = 2920, 2855, 1639, 1595,
1426, 1231, 1092 cm−1; HRMS (ESIꢀQTOF) m/z [M+H]+ calcd for C20H16NO 286.1226,
found 286.1245.

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(4-Fluorophenyl)(7-methylpyrrolo[1,2-a]quinolin-5-yl)methanone (6o). Yellow solid; mp:
1
117.2ꢀ118.6 °C (34 mg, 89.5%); H NMR (400 MHz, CDCl3) δ 8.08 (s, 1H), 7.93ꢀ7.97 (m,
3H), 7.86 (d, J = 8.5 Hz, 1H), 7.53 (s, 1H), 7.40 (d, J = 8.4 Hz, 1H), 7.17 (t, J = 8.6 Hz, 2H),
6.86 (t, J = 3.3 Hz, 1H), 6.72 (d, J = 3.6 Hz, 1H), 2.45 (s, 3H); 13C NMR (100 MHz, CDCl3)
δ 194.8, 165.7 (d, J = 252.7 Hz), 135.2 (d, J = 2.9 Hz), 134.0, 132.8 (d, J = 9.1 Hz), 131.2,
129.8, 128.4, 127.4, 125.5, 124.6, 121.2, 115.7 (d, J = 21.5 Hz), 114.5, 114.4, 114.1, 107.6,
21.4; IR (ATR) ν = 3039, 2922, 1641, 1593, 1261, 1089 cm−1; HRMS (ESIꢀQTOF) m/z
[M+H]+ calcd for C20H15FNO 304.1132, found 304.1140.
(4-Methoxyphenyl)(7-methylpyrrolo[1,2-a]quinolin-5-yl)methanone (6p). Yellow solid;
1
mp: 106.3ꢀ107.7 °C (24.8 mg, 82.7%); H NMR (400 MHz, CDCl3) δ 7.94ꢀ7.99 (m, 4H),
7.85 (d, J = 8.6 Hz, 1H), 7.51 (m, 1H), 7.38 (d, J = 8.8 Hz, 1H), 6.97 (d, J = 8.2 Hz, 2H), 6.84
(s, 1H), 6.68 (s, 1H), 3.90 (s, 3H), 2.43 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 195.1, 163.7,
133.8, 132.7, 131.4, 131.3, 129.7, 128.7, 127.4, 126.4, 123.4, 121.5, 114.4, 114.0, 113.8,
106.8, 55.7, 21.4; IR (ATR) ν = 3070, 2862, 1653, 1524, 1386, 1075 cm−1; HRMS (ESIꢀ
QTOF) m/z [M+H]+ calcd for C21H18NO2 316.1332, found 316.1348.
(7-Methylpyrrolo[1,2-a]quinolin-5-yl)(thiophen-3-yl)methanone (6q). Yellow gum (29.6
1
mg, 84.6%); H NMR (400 MHz, CDCl3) δ 8.11 (s, 1H), 7.98 (t, J = 1.4 Hz, 1H), 7.94 (s,
1H), 7.84 (d, J = 8.5 Hz, 1H), 7.71 (s, 1H), 7.67 (dd, J = 0.7, 5.0 Hz, 1H), 7.37ꢀ7.42 (m, 2H),
6.85 (t, J = 3.3 Hz, 1H), 6.73 (d, J = 3.0 Hz, 1H), 2.45 (s, 3H); 13C NMR (100 MHz, CDCl3)
δ 189.6, 143.1, 134.1, 133.98, 131.3, 129.8, 128.6, 128.5, 127.3, 126.7, 126.5, 123.8, 120.98,