Propargyl alcohols as alkyne sources: Synthesis of heterocyclic compounds under microwave irradiation

Article abstract of DOI:10.1016/j.jorganchem.2020.121350

Fused heterocyclic compounds with alkyne substituent, have been achieved using a domino microwave-assisted [Pd]-catalysis. Interestingly, tert-propargyl alcohols underwent a selective degradative β-carbon cleavage and served as masked alkynyl equivalents, in water as the sole reaction medium. Dihydrobenzofurans, indolines, and oxindoles have been accomplished using this dual C–C bond-forming strategy.

Full text of DOI:10.1016/j.jorganchem.2020.121350

Journal Pre-proof
Propargyl alcohols as alkyne sources: Synthesis of heterocyclic compounds under
microwave irradiation
Karu Ramesh, Gedu Satyanarayana
PII:
S0022-328X(20)30252-7
DOI:
https://doi.org/10.1016/j.jorganchem.2020.121350
JOM 121350
Reference:
To appear in: Journal of Organometallic Chemistry
Received Date: 9 February 2020
Revised Date: 12 May 2020
Accepted Date: 20 May 2020
Please cite this article as: K. Ramesh, G. Satyanarayana, Propargyl alcohols as alkyne sources:
Synthesis of heterocyclic compounds under microwave irradiation, Journal of Organometallic Chemistry
(2020), doi: https://doi.org/10.1016/j.jorganchem.2020.121350.
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Propargyl Alcohols as Alkyne Sources: Synthesis of Heterocyclic Compounds
under Microwave Irradiation
Karu Ramesh and Gedu Satyanarayana*
Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi – 502 285, Sangareddy, Telangana, INDIA
Phone: (040) 2301 6033; Fax: (040) 2301 6003 / 32, E-mail: gvsatya@iith.ac.in
Abstract: Fused heterocyclic compounds with alkyne substituent, have been achieved using a domino
microwave-assisted [Pd]-catalysis. Interestingly, tert-propargyl alcohols underwent a selective
degradative β-carbon cleavage and served as masked alkynyl equivalents, in water as the sole reaction
medium. Dihydrobenzofurans, indolines, and oxindoles have been accomplished using this dual C−C
bond-forming strategy.
Keywords: [Pd]-Catalysis; tert-Propargyl alcohols; Aqueous medium; Microwaves;
Heterocycles.
Introduction
By nature, alcohols could be able to form associated complexes with transition metals
through their coordinating ability. Further, these complexes may break down into an alkyl-metal
species and an elimination product(s) via β-elimination.1 The alkyl-metal species could, in turn,
either undergo usual β-hydrogen elimination to give olefin products or subsequent couplings to
deliver interesting organic products.2 Though in the recent past, some interesting examples have
appeared in the literature on the cleavage of C−C bond, mediated by transition-metal catalysts,3
still the concept has been pursued in a limited fashion. Miura et al. disclosed a palladium-
catalyzed biaryls synthesis by selective cleaving of Csp3−Csp2 bond of dialkylarylmethanols
with aryl halides.4 Later, the research group of Sakae Uemura presented alkynylation of alkenes
via C−C bond scission of tert-propargyl alcohols under oxidative conditions with [Pd]-catalyst.5

Of late, Sayuri Hayashi et al. demonstrated the retro-propargylation of tert-homopropargyl
alcohols providing allenes facilitated by palladium.6
Recently, we were succeeded in the synthesis of benzochromenes via a domino
homocoupling α,α-dialkyl-(2-bromoaryl)methanols, and β-carbon cleavage, under palladium
catalysis.7 Also, demonstrated [Pd]-catalyzed Heck and Sonagashira couplings towards bicyclic
systems, under microwave assisting conditions. Further, the concept was extended to Heck and
decarboxylative Sonogashira reaction. That affords heterocyclic products possessing short alkyl
groups via Heck and decarboxylative Sonogashira reaction.8 Propiolic acids have been utilized as
the alkynyl source, for this purpose. In continuation of our research interest on palladium
catalysis,9 in this manuscript, we describe a strategy for the preparation of dihydrobenzofurans,
indolines, and oxindoles. The process was smooth under microwave-accelerated conditions and
by using utilizing water as the sole green reaction medium in the presence of palladium-catalyst.
Notably, tert-propargyl alcohols have undergone a selective β-carbon cleavage and served as
masked alkynyl equivalents.
Result and Discussions
It was anticipated that after intramolecular Heck step of allyl ortho-iodoaryl ethers, tert-
propargyl alcohols could act as masked alkynyl sources. That can be accomplished by β-carbon
cleavage of tert-alcohol function facilitated by palladium catalyst, affording the
dihydrobenzofurans linked to an alkynyl moiety.
To begin the optimization study, 2-iodoaryl allyl ether 1a and propargyl alcohol 2a were
identified as the starting materials. Based on our earlier studies, initially, 1a and 2a were
irradiated using microwaves with a catalytic amount 1 mol% of Pd2(dba)3 and K2CO3 (4 equiv)
in solvent DMF (0.5 mL) at 100 °C (entry 1, Table 1).10 To our delight, the desired bicyclic ether
3aa was isolated in 80% yield. As our interest is to use water as the sole solvent, the reactions
have been performed with 0.5 mL of water under the same conditions; however, 3aa was formed
in poor yields (entries 2 to 4, Table 1). A significant jump in the yield of 3aa was noticed by
using quaternary ammonium salt TBAI (tetrabutylammonium iodide) as an additive (entry 5,
Table 1). Slight improvement in the yield of the product 3aa (78%) was observed when benzyl

triethylammonium chloride (BTEAC) was used as the additive and in the presence of base
K2CO3 (entry 6, Table 1). While the reaction with an organic base DBU (1,8-
diazabicyclo[5.4.0]undec-7-ene), turned out to be very much inferior (entry 7, Table 1). While
tetrabutylammonium bromide (TBAB) proved to better, since the product 3aa was afforded in
80% yield (entry 8, Table 1). However, when the Pd2(dba)3 loading was increased to 5 mol%, it
gave 90% yield of the desired product 3aa (entry 9, Table 1). Furthermore, the reaction with the
additive TBAB and the base K2CO3 with the reduced irradiation time 5 and 10 min, delivered
3aa in 30 and 40% yields, respectively (entries 10 to 11, Table 1).
Table 1. Optimizations for 3aa.a-c
OH
Me
H2O
O
O
O
I
Me
Me
[Pd]/ligand
base, additive
MW, heat
+
Me
Me
Me
1a
2a
3aa
8
entry
additive
(1 equiv)
-
base
solvent
time
yield
(4 equiv)
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
DBU
K2CO3
K2CO3
K2CO3
K2CO3
(min) 3aab (%)
1
2
3
4
5
6
7
8
9c
10c
11c
DMF
H2O
H2O
H2O
H2O
H2O
H2O
H2O
H2O
H2O
H2O
20
20
25
30
20
20
20
20
20
5
(80%)
(15%)
(20%)
(25%)
(75%)
(78%)
(40%)
(80%)
(90%)
(30%)
(40%)
-
-
-
TBAI
BTEAC
BTEAC
TBAB
TBAB
TBAB
TBAB
10
aConditions: all reactions were performed under microwave irradiation (300 W, closed vessel, 100 °C, 5 to 30 minutes) using 1a
(0.25 mmol), 2a (0.50 mmol), additive (1 equiv), base (4 equiv), 1 mol% of Pd2(dba)3 and DMF (or) water (0.5 mL) as solvents.
bIsolated yield of the product 3aa. cPd2(dba)3 (5 mol%).
From the above best-optimized conditions (entry 9, Table 1) to give dihydrobenzofuran
3aa and hence, decided to explore these conditions with other substrates. Consequently, various
allyl ortho-iodophenyl ethers 1a-1f, and tert-propargyl alcohols 2a-2i were reacted using
established standard conditions. Significantly, the protocol seemed to be quite smooth and
afforded dihydrobenzofruans 3aa-3fa bearing alkyne moiety, in fair to good yields (Table 2).

Alkyl, as well as phenyl substituted allyl ortho-iodophenyl ethers, underwent smoothly to deliver
the desired products 3. Notably, the strategy was also compatible with aliphatic, aryl and cyclic
tert-propargyl alcohols. Moreover, the strategy was also successful with a free amine functional
group connected to the aromatic moiety of propargyl alcohol 2g (3dg, Table 2).
Table 2: Substrate scope of the products 3aa-3fa.a-c
aReaction conditions: 1a-1f (0.25 mmol), 2a-2i (0.50 mmol), Pd2(dba)3 (5 mol%), TBAB (1 equiv), K2CO3 (4 equiv), H2O (0.5
b
mL), 20-30 minutes, 100 °C (closed vessel, 300 W). Isolated yields. cThe first alphabet of bicyclic ethers 3aa-3fa indicating 2-
iodophenyl allyl ethers, while, second letter is representing propargyl alcohols 2a-2i.
In addition, to prove that the reaction pathway is proceeding through degradative
cleavage of propargyl alcohols and generating ketones as a by-product, it was planned to study
the NMR of crude reaction products. Thus, after completion of the reaction, with the help of a
short plug of silica filtered the resultant crude mixture, (i.e., products 3aa and 8a formed from

the reaction of 1a and 2c); bulk solvent was removed under reduced pressure using a rotary
1
evaporator; followed by high vacuum pump. Then submitted the crude reaction mixture to H-
NMR analysis in CDCl3 using CH2Br2 as the internal standard. From NMR study revealed the
formation of acetophenone by-product 8a in 85% of NMR yield (isolated yield 80%), in which
1
the methyl group protons are significant and appeared at δ 2.59 of its H-NMR spectrum. Also,
the desired product 3aa was obtained in 78% of NMR yield (isolated yield is 74%, Scheme 1)
[See supporting information for crude spectrum]. Thus, it is confirmed that ketones are generated
as by-products from propargyl alcohols, and this could be feasible via degradative β-cleavage of
a C−C bond.11
Scheme 1: NMR analysis for crude products of 3aa and 8a.
Furthermore, it was intended to demonstrate the scope and diversity of the methodology.
Therefore, ortho-iodoarylmethallylamines 4a-4c and tert-propargyl alcohols 2a-2i were reacted,
under standard microwave-accelerated conditions. As predicted, indolines 5aa-5ci were obtained
in fair to good yields with broad functional group tolerance (Table 3). In addition, to reveal the
importance and applicability of this strategy, ortho-iodophenyl enamides 6a-6d were also
irradiated under microwaves with tert-propargyl alcohols 2a-2i, using established reaction
parameters. As anticipated, the target oxindoles 7aa-7da have also been obtained and thus,

reflects the synthetic utility of this methodology (Table 3). It is worth mentioning that the
reaction of N-Ts protected allyl ortho-iodophenyl amine was treated with propargyl alcohol
using the standard reaction conditions; however, the reaction was not amenable to deliver the
desired indoline product, instead ended up in forming the simple deprotected ortho-iodophenyl
amine without any cyclization.
Table 3: Synthesis of indolines & oxindoles (5aa-5ci & 7aa-7da).a-c
aReaction conditions: 4a-4c (0.25 mmol)/6a-6c (0.25 mmol), 2a-2i (0.50 mmol), Pd2(dba)3 (5 mol%), TBAB (1 equiv), K2CO3 (4
equiv), H2O (0.5 mL), 20-30 minutes, 100 °C (closed vessel, 300 W). bIsolated yields. cThe first alphabet of products 5aa-5ci &
7aa-7da indicating 2-iodo-N-alkyl/aryl-N-(2-methylallyl)anilines/N-(2-iodophenyl)-N-alkylmethacrylamide while, second letter
is for propargyl alcohols 2a-2i.
A plausible mechanism for the formation of 3/5/7 is outlined in Scheme 2. Initially,
active Pd(0) catalyst inserts onto across the C(sp2)-I bond of starting material 1/4/6 via oxidative
insertion and leads to organopalladium(II) intermediate A. Consequently, intramolecular Heck

cyclization of the intermediate A affords the bicyclic alkyl-Pd(II) species B. Combination of
propargyl alcohol 2 with the bicyclic Pd(II) intermediate B affords C through the removal of KI
and KHCO3. Subsequently, degradative C−C bond β-cleavage of ethereal species C furnishes a
new Pd(II) intermediate D via the expulsion of ketone by-product 8. Finally, the reductive
elimination of the palladium catalyst from D through concomitant C−C bond formation produces
the desired heterocyclic product 3/5/7 along with the regeneration of the Pd(0) catalyst.
Scheme 2: Plausible reaction mechanism for the formation of heterocycles 3/5/7.
Conclusions
In conclusion, we have established a domino palladium-catalyzed procedure for constructing a
quaternary carbon-containing fused heterocyclic compounds with alkynyl functionality.
Significantly, tert-propargyl alcohols were employed as masked alkyne sources and proceeds via
the cleavage of the β-carbon atom of the alcoholic group. Also, the reaction was successful by
means of water as the sole green reaction medium under microwave-accelerated conditions.

Experimental
1
General: IR spectra were recorded on a Bruker Tensor 37 (FTIR) spectrophotometer. H NMR
spectra were recorded on Bruker Avance 400 (400 MHz) spectrometer at 295 K in CDCl3;
chemical shifts (δ ppm) and coupling constants (Hz) are reported in standard fashion with
reference to either internal standard tetramethylsilane (TMS) (δH = 0.00 ppm) or CDCl3 (δH =
7.25 ppm). 13C{1H} NMR spectra were recorded on Bruker Avance 400 (100 MHz) spectrometer
at RT in CDCl3; chemical shifts (δ ppm) are reported relative to CDCl3 [δC = 77.00 ppm (central
line of the triplet)]. In the 13C{1H} NMR, the nature of carbons (C, CH, CH2, and CH3) was
determined by recording the DEPT-135 spectra, and is given in parentheses and noted as s =
1
singlet (for C), d = doublet (for CH), t = triplet (for CH2) and q = quartet (for CH3). In the H-
NMR, the following abbreviations were used throughout: s = singlet, d = doublet, t = triplet, q =
quartet, qui = quintet, sept = septet, dd = doublet of doublets, m = multiplet and br. s = broad
singlet. The assignment of signals was confirmed by 1H, 13C{1H} CPD, and DEPT spectra. High-
resolution mass spectra (HR-MS) were recorded on an Agilent 6538 UHD Q-TOF electron spray
ionization (ESI) mode and atmospheric pressure chemical ionization (APCI) modes. The
microwave irradiation experiments were carried out in a dedicated CEM-Discover monomode
microwave apparatus, operating at a frequency of 2.45 GHz with continuous irradiation power
from 0 to 300 W and utilization of the standard absorbance level of 100 W. The reactions were
carried out in 10 mL glass vials fitted with Teflon septum. The reactions were irradiated at the
required temperature for the stipulated time and then cooled to ambient temperature with air-jet
cooling. Reactions were monitored by TLC on silica gel using a combination of hexane and ethyl
acetate as eluents. Reactions were generally run under argon or nitrogen atmosphere. Solvent(s)
were distilled prior to use; petroleum ether with a boiling range of 60 to 80 °C was used.
Pd2(dba)3, and K2CO3 were purchased from Sigma-Aldrich and used as received. ortho-
Iodophenols, ortho-iodoanilines, TBAB (tetrabutylammonium bromide), 3-chloro-2-methylprop-
1-ene, and terminal acetylenes were purchased from Sigma-Aldrich/TCI/local sources and used
as received. Acme’s silica gel (60–120 mesh) was used for column chromatography
(approximately 20 g per one gram of crude material). It is worth noting that these sort of
experimental procedures have already been published elsewhere.7-9

GP (General Procedure for the Synthesis of 3,3’-Disubstituted Heterocyclic Compounds
3/5/7): An oven-dried 10 mL microwave tube fitted with teflon septum was equipped with a
magnetic stir bar. The vial was charged with ortho-iodoaryl allyl ethers 1 (or) ortho-iodophenyl
allyl amines 4 (or) ortho-iodophenyl enamides 6 (68-88 mg, 0.25 mmol), propargylic alcohols
2 (60-106.5 mg, 0.5 mmol), Pd2(dba)3 (11.4 mg, 5 mol%), K2CO3 (138.6 mg, 1 mmol) TBAB
(80.5 mg, 0.25 mmol), followed by solvent water (0.5mL), at room temperature. The resultant
reaction mixture was then subjected to microwave irradiation at 100 °C for 20-30 min (300 W,
closed vessel). The progress of the reaction was monitored by TLC until the reaction is
completed. The mixture was cooled to room temperature, quenched with aqueous NaHCO3
solution and extracted with ethyl acetate (3 × 10 mL). The organic layers were washed with a
saturated NaCl solution, dried (Na2SO4), and filtered. Evaporation of the solvent(s) under
reduced pressure and purification of the crude mixture by silica gel column chromatography
(petroleum ether/ethyl acetate), furnished the 3,3’-disubstituted heterocyclic compounds 3/5/7
(60‒90%) as oil/semi-solid.
3-[3-(3-Fluorophenyl)prop-2-ynyl]-3-methyl-2,3-dihydro-1-benzofuran (3ah): GP was
carried out with 1-iodo-2-[(2-methylprop-2-enyl)oxy]benzene 1a (68.5 mg, 0.25 mmol), 4-(3-
fluorophenyl)-2-methylbut-3-yn-2-ol 2h (87.5mg, 0.50 mmol), Pd2(dba)3 (11.4 mg, 5 mol%),
TBAB (80.5 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol) water (0.5 mL), under microwave
irradiation. Purification of the crude material by silica gel column chromatography (petroleum
ether/ethyl acetate, 100:0 to 97:3) furnished the product 3ah (45.8 mg, 69%) as a colourless oily
compound, [TLC control (petroleum ether/ethyl acetate 99:1), Rf(1a)=0.8, Rf(3ah)=0.7, UV
detection]. IR (MIR-ATR, 4000–600 cm-1):
νmax=2933, 2891, 1586, 1471, 1297, 1252, 971, 872,
774, 727, 686 cm-1. 1H NMR (400 MHz, CDCl3) δ=7.30–7.21 (m, 2H), 7.20–7.13 (m, 2H), 7.10–
7.04 (m, 1H), 7.03–6.96 (m, 1H), 6.91 (ddd, J = 7.4, 7.4 and 1.0 Hz, 1H), 6.83 (dd, J = 7.4 and
1.0 Hz, 1H), 4.54 (d, J = 8.8 Hz, 1H), 4.24 (d, J = 8.8 Hz, 1H), 2.68 (s, 2H), 1.54 (s, 3H) ppm.
13C NMR (100 MHz, CDCl3) δ=162.3 (d, J = 246.1 Hz), 161.1, 159.4, 133.8, 129.8 (d, J = 8.7
Hz), 128.6, 127.5 (d, J = 3.1 Hz), 122.9, 120.6, 118.4 (d, J = 22.6 Hz), 115.2 (d, J = 21.2 Hz)
109.8, 87.8, 82.2, 81.3, 45.3, 31.5, 24.2 ppm. HR-MS (ESI+) m/z calculated for
[C18H16FO]+=[M+H]+: 267.1180; found 267.1157.

5-Ethyl-3-[3-(3-fluorophenyl)prop-2-ynyl]-3-methyl-2,3-dihydro-1-benzofuran (3ch): GP
was carried out with 4-ethyl-2-iodo-1-[(2-methylprop-2-enyl)oxy]benzene 1c (75.5 mg, 0.25
mmol), 4-(3-fluorophenyl)-2-methylbut-3-yn-2-ol 2h (87.5 mg, 0.50 mmol), Pd2(dba)3 (11.4 mg,
5 mol%), TBAB (80.5 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol) water (0.5 mL), under
microwave irradiation. Purification of the crude material by silica gel column chromatography
(petroleum ether/ethyl acetate, 100:0 to 97:3) furnished the product 3ch (49.2 mg, 67%) as a pale
yellow oily compound, [TLC control (petroleum ether/ethyl acetate 99:1), Rf(1c)=0.8,
Rf(3ch)=0.7, UV detection]. IR (MIR-ATR, 4000–600 cm-1):
νmax=2933, 1592, 1563, 1468,
1256, 1213, 1144, 971, 865, 811, 773 cm-1. 1H NMR (400 MHz, CDCl3) δ=7.25 (td, J = 7.8 and
3.9 Hz, 1H), 7.17 (d, J = 7.7 Hz, 1H), 7.07 (dd, J = 11.8 and 5.4 Hz, 2H), 7.00 (ddd, J = 5.8, 3.7
and 2.2 Hz, 2H), 6.75 (d, J = 8.1 Hz, 1H), 4.53 (d, J = 8.8 Hz, 1H), 4.23 (d, J = 8.8 Hz, 1H), 2.68
(s, 2H), 2.62 (q, J = 7.6 Hz, 2H), 1.54 (s, 3H), 1.23 (t, J = 7.6 Hz, 3H) ppm. 13C NMR (100 MHz,
CDCl3) δ=163.6, 161.1, 157.5, 136.6, 133.8, 129.8, 129.7, 127.9, 127.4, 127.4, 125.4, 125.3,
122.2, 118.5, 118.3, 115.3, 115.1, 109.4, 88.0, 82.4, 81.3, 45.3, 31.5, 28.4, 24.0, 16.0 ppm. HR-
MS (ESI+) m/z calculated for [C20H20FO]+=[M+H]+: 295.1493; found 295.1496.
3-(3-Cyclopropylprop-2-ynyl)-5-ethyl-3-methyl-2,3-dihydro-1-benzofuran (3ci): GP was
carried out with 4-ethyl-2-iodo-1-[(2-methylprop-2-enyl)oxy]benzene 1c (75.5 mg, 0.25 mmol),
4-cyclopropyl-2-phenylbut-3-yn-2-ol 2i (93 mg, 0.50 mmol), Pd2(dba)3 (11.4 mg, 5 mol%),
TBAB (80.5 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol) water (0.5 mL), under microwave
irradiation. Purification of the crude material by silica gel column chromatography (petroleum
ether/ethyl acetate, 100:0 to 99:1) furnished the product 3ci (43.5 mg, 69%) as a colorless
compound, [TLC control (petroleum ether/ethyl acetate 100:0), Rf(1c)=0.8, Rf(3ci)=0.7, UV
detection]. IR (MIR-ATR, 4000–600 cm-1):
νmax= 2933, 2891, 1586, 1471, 1297, 1252, 970, 871,
774, 727, 686 cm-1. 1H NMR (CDCl3, 400 MHz): δ=6.97 (s, 1H, Ar–H), 6.95 (dd, J = 7.8 and 1.0
Hz, 1H, Ar–H), 6.69 (dd, J = 7.8 and 1.0 Hz, 1H, Ar–H), 4.42 (d, J = 8.8 Hz, 1H, OCHAHB),
4.13 (d, J = 8.8 Hz, 1H, OCHAHB), 2.58 (q, J = 7.8 Hz, 2H), 2.37 (s, 2H), 1.42 (s, 3H, CH3), 1.21
(t, J = 7.6 Hz, 3H), 1.25–1.15 (m, 1H), 0.76–0.67 (m, 2H), 0.66–0.55 (m, 2H) ppm. 13C NMR
(CDCl3, 100 MHz): δ= 157.4, 136.3, 134.2, 127.6, 122.2, 109.2, 85.3, 82.4, 72.0, 45.2, 30.9,
28.4, 24.0, 16.0, 8.0, -0.50 ppm. HR-MS (ESI+) m/z calculated for [C17H21O]+=[M+H]+:
241.1587; found 241.1588.

5-tert-butyl-3-methyl-3-[3-(3-methylphenyl)prop-2-ynyl]-2,3-dihydro-1-benzofuran (3de):
GP was carried out with 4-tert-butyl-2-iodo-1-[(2-methylprop-2-enyl)oxy]benzene 1d (82.5 mg,
0.25 mmol), 2-methyl-4-(3-methylphenyl)but-3-yn-2-ol 2e (87 mg, 0.50 mmol), Pd2(dba)3 (11.4
mg, 5 mol%), TBAB (80.5 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol) water (0.5 mL), under
microwave irradiation. Purification of the crude material by silica gel column chromatography
(petroleum ether/ethyl acetate, 100:0 to 99:01) furnished the product 3de (69.9 mg, 72%) as a
colorless oily compound, [TLC control (petroleum ether/ethyl acetate 100:0), Rf(1d)=0.8,
Rf(3de)=0.7, UV detection]. IR (MIR-ATR, 4000–600 cm-1):
νmax=2928, 1588, 1471, 1352,
1247, 972, 875, 810, 774, 685 cm-1. 1H NMR (CDCl3, 400 MHz): δ=7.27 (d, J = 2.0 Hz, 1H, Ar–
H), 7.24–7.14 (m, 4H, Ar–H), 7.10 (dd, J = 8.3 and 1.0 Hz, 1H, Ar–H), 6.74 (d, J = 8.3 Hz, 1H,
Ar–H), 4.51 (d, J = 8.8 Hz, 1H, OCHAHB), 4.22 (d, J = 8.8 Hz, 1H, OCHAHB), 2.67 (s, 2H, CH2),
2.32 (s, 3H, CH3), 1.54 (s, 3H, CH3), 1.30 (s, 9H, 3 × CH3) ppm. 13C NMR (CDCl3, 100 MHz):
δ=157.2, 143.6, 137.9, 133.6, 132.2, 128.7, 128.6, 128.1, 125.3, 123.3, 119.8, 108.9, 86.5, 82.6,
82.5, 45.4, 34.4, 31.7, 31.5, 23.9, 21.1 ppm. HR-MS (ESI+) m/z calculated for
[C23H27O]+=[M+H]+: 319.2056; found 319.2056.
3-[3-(5-tert-Butyl-3-methyl-2,3-dihydro-1-benzofuran-3-yl)prop-1-ynyl]aniline (3dg): GP
was carried out with 4-tert-butyl-2-iodo-1-[(2-methylprop-2-enyl)oxy]benzene 1d (82.5 mg, 0.25
mmol), 4-(3-aminophenyl)-2-methylbut-3-yn-2-ol 2g (87.5 mg, 0.50 mmol), Pd2(dba)3 (11.4 mg,
5 mol%), TBAB (80.5 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol) water (0.5 mL), under
microwave irradiation. Purification of the crude material by silica gel column chromatography
(petroleum ether/ethyl acetate, 100:0 to 97:3) furnished the product 3dg (51.9 mg, 65%) as a
semi solid, [TLC control (petroleum ether/ethyl acetate 99:1), Rf(1d)=0.8, Rf(3dg)=0.7, UV
detection]. IR (MIR-ATR, 4000–600 cm-1):
νmax= 3340, 2928, 1592, 1471, 1351, 1287, 1250,
1195, 968, 860, 809, 771, 730, 678 cm-1. 1H NMR (400 MHz, CDCl3) δ=7.79–7.73 (m, 1H), 7.68
(dd, J = 8.4, 2.1 Hz, 1H), 7.57 (t, J = 7.8 Hz, 1H), 7.31 (d, J = 7.6 Hz, 1H), 7.26–7.20 (m, 2H),
7.11 (ddd, J = 8.0, 2.3, 0.8 Hz, 1H), 5.01 (d, J = 8.8 Hz, 1H), 4.71 (d, J = 8.8 Hz, 1H), 4.13 (s,
13
2H), 3.16 (s, 2H), 2.03 (s, 3H), 1.79 (s, 9H) ppm. C NMR (100 MHz, CDCl3) δ=157.1, 146.2,
143.6, 133.6, 129.2, 125.3, 124.2, 122.0, 119.8, 117.9, 114.9, 108.9, 86.2, 82.6, 45.4, 34.4, 31.7,

31.5, 23.9 ppm. HR-MS (ESI+) m/z calculated for [C22H26NO]+=[M+H]+: 320.2009; found
320.2026.
3-Methyl-3-[3-(3-methylphenyl)prop-2-ynyl]-5-phenyl-2,3-dihydro-1-benzofuran (3ee): GP
was carried out with 3-iodo-1,1'-biphenyl-4-yl 2-methylprop-2-enyl ether 1e (87.5 mg, 0.25
mmol), 2-methyl-4-(3-methylphenyl)but-3-yn-2-ol 2e (87 mg, 0.50 mmol), Pd2(dba)3 (11.4 mg, 5
mol%), TBAB (80.5 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol) water (0.5 mL), under
microwave irradiation. Purification of the crude material by silica gel column chromatography
(petroleum ether/ethyl acetate, 100:0 to 99:01) furnished the product 3ee (59.9 mg, 71%) as a
yellow jelly compound, [TLC control (petroleum ether/ethyl acetate 100:0), Rf(1e)=0.7,
Rf(3ee)=0.6, UV detection]. IR (MIR-ATR, 4000–600 cm-1):
νmax=3000, 1586, 1459, 1252, 1026,
877, 813, 752, 687 cm-1. 1H NMR (CDCl3, 400 MHz): δ=7.57–7.50 (m, 2H, Ar–H), 7.48 (d, 1H,
J = 2.0 Hz, Ar–H), 7.44–7.35 (m, 4H, Ar–H), 7.33–7.25 (m, 2H, Ar–H), 7.23–7.14 (m, 2H, Ar–
H), 6.87 (d, 1H, J = 8.3 Hz, Ar–H), 4.58 (d, J = 8.8 Hz, 1H, OCHAHB), 4.29 (d, J = 8.8 Hz, 1H,
OCHAHB), 2.71 (s, 2H, CH2), 2.28 (s, 3H, CH3), 1.54 (s, 3H, CH3) ppm. 13C NMR (CDCl3, 100
MHz): δ=159.2, 141.3, 137.9, 134.7, 134.2, 132.2, 128.8, 128.7, 128.1, 127.6, 126.8, 126.5,
123.2, 122.1, 109.9, 86.2, 82.8, 82.7, 45.4, 31.6, 24.1, 21.2 ppm. HR-MS (ESI+) m/z calculated
for [C25H23O]+=[M+H]+: 339.1743; found 339.1746.
3-(3-Cyclopropylprop-2-ynyl)-3-methyl-5-phenyl-2,3-dihydro-1-benzofuran (3ei): GP was
carried out with 3-iodo-1,1'-biphenyl-4-yl 2-methylprop-2-enyl ether 1e (87.5 mg, 0.25 mmol),
4-cyclopropyl-2-phenylbut-3-yn-2-ol 2i (93 mg, 0.50 mmol), Pd2(dba)3 (11.4 mg, 5 mol%),
TBAB (80.5 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol) water (0.5 mL), under microwave
irradiation. Purification of the crude material by silica gel column chromatography (petroleum
ether/ethyl acetate, 100:0 to 99:01) furnished the product 3ei (50 mg, 70%) as a pale yellow oily
compound, [TLC control (petroleum ether/ethyl acetate 99:1), Rf(1e)=0.8, Rf(3ei)=0.7, UV
detection]. IR (MIR-ATR, 4000–600 cm-1):
νmax= 2933, 1703, 1472, 1359, 1211, 1019, 969, 877,
807, 753 cm-1. 1H NMR (CDCl3, 400 MHz): δ=7.59–7.54 (m, 2H, Ar–H), 7.44–7.38 (m, 4H, Ar–
H), 7.34–7.27 (m, 2H, Ar–H), 6.87 (d, J = 7.8 Hz, 1H, Ar–H), 4.52 (d, J = 8.8 Hz, 1H,
OCHAHB), 4.24 (d, J = 8.8 Hz, 1H, OCHAHB), 2.46 (d, J = 2.0 Hz, 2H), 1.50 (s, 3H, CH3), 1.27–
1.16 (m, CH, 1H), 0.80–0.70 (m, CH2, 2H), 0.63–0.58 (m, CH2, 2H) ppm. 13C NMR (CDCl3, 100

MHz): δ= 159.1, 141.3, 134.9, 134.0, 128.6, 127.4, 126.7, 126.5, 121.8, 109.8, 85.6, 82.7, 71.8,
45.2, 31.0, 24.2, 8.0, -0.52 ppm. HR-MS (ESI+) m/z calculated for [C21H21O]+=[M+H]+:
289.1587; found 289.1589.
1,3-Dimethyl-3-[3-(3-methylphenyl)prop-2-ynyl]indoline (5ae): GP was carried out with 2-
iodo-N-methyl-N-(2-methylallyl)aniline 4a (71.7 mg, 0.25 mmol), 2-methyl-4-(3-
methylphenyl)but-3-yn-2-ol 2e (87 mg, 0.50 mmol), Pd2(dba)3 (11.4 mg, 5 mol%), TBAB (80.5
mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol) water (0.5 mL), under microwave irradiation.
Purification of the crude material by silica gel column chromatography (petroleum ether/ethyl
acetate, 100:0 to 99:1) furnished the product 5ae (49.4 mg, 72%) as a colorless oily compound,
[TLC control (petroleum ether/ethyl acetate 100:0), Rf(4a)=0.9, Rf(5ae)=0.8, UV detection]. IR
(MIR-ATR, 4000–600 cm-1): max=2924, 2888, 1586, 1471, 1439, 1254, 1092, 773, 737, 688 cm-
ν
1
1. H NMR (CDCl3, 400 MHz): δ=7.28–7.18 (m, 3H, Ar–H), 7.17-7.07 (m, 3H, Ar–H), 6.70
(ddd, J = 7.3, 7.3 and 1.0 Hz, 1H, Ar–H), 6.50 (d, J = 7.3 Hz, 1H, Ar–H), 3.43 (d, J = 8.8 Hz,
1H, NCHAHB), 3.04 (d, J = 8.8 Hz, 1H, NCHAHB), 2.77 (s, 3H, CH3), 2.64 (s, 2H, CH2), 2.33 (s,
13
3H, CH3), 1.51 (s, 3H, CH3) ppm. C NMR (CDCl3, 100 MHz): δ=152.2, 137.8, 136.6, 132.2,
128.6, 128.5, 128.1, 128.0, 123.6, 122.3, 117.7, 107.4, 87.4, 82.3, 67.9, 43.7, 35.8, 30.8, 23.9,
21.2 ppm. HR-MS (ESI+) m/z calculated for [C20H22N]+=[M+H]+: 276.1747; found 276.1755.
3-[3-(3-Fluorophenyl)prop-2-ynyl]-1,3-dimethylindoline (5ah): GP was carried out with 2-
iodo-N-methyl-N-(2-methylallyl)aniline 4a (71.7 mg, 0.25 mmol), 4-(3-fluorophenyl)-2-
methylbut-3-yn-2-ol 2h (87.5 mg, 0.50 mmol), Pd2(dba)3 (11.4 mg, 5 mol%), TBAB (80.5 mg,
0.25 mmol), K2CO3 (138.6 mg, 1 mmol) water (0.5 mL), under microwave irradiation.
Purification of the crude material by silica gel column chromatography (petroleum ether/ethyl
acetate, 100:0 to 97:3) furnished the product 5ah (48 mg, 69%) as a colorless oily compound,
[TLC control (petroleum ether/ethyl acetate 99:1), Rf(4a)=0.8, Rf(5ah)=0.7, UV detection]. IR
(MIR-ATR, 4000–600 cm-1): max=2926, 2891, 1588, 1475, 1254, 744, 687 cm-1. 1H NMR (400
ν
MHz, CDCl3) δ=7.29–7.21 (m, 1H), 7.19–7.13 (m, 1H), 7.13–7.06 (m, 2H), 7.04–6.94 (m, 2H),
6.72 (ddd, J = 7.4, 7.4 and 0.8 Hz, 1H), 6.51 (d, J = 7.8 Hz, 1H), 3.40 (d, J = 8.8 Hz, 1H), 3.03
(d, J = 8.8 Hz, 1H), 2.77 (s, 3H), 2.67–2.61 (m, 2H), 1.49 (s, 3H) ppm. 13C NMR (100 MHz,
CDCl3) δ=163.6, 161.1, 152.2, 136.4, 129.8, 129.7, 128.1, 127.5, 122.3, 118.5, 118.3, 117.8,

115.1, 114.9, 107.5, 89.0, 81.1, 43.7, 35.8, 30.7, 23.9 ppm. HR-MS (ESI+) m/z calculated for
[C19H19FN]+=[M+H]+: 280.1496; found 280.1503.
1-Ethyl-3-methyl-3-(3-phenylprop-2-ynyl)indoline (5ba): GP was carried out with 2-iodo-N-
ethyl-2-iodo-N-(2-methylallyl)aniline 4b (75.2 mg, 0.25 mmol), 2-methyl-4-phenylbut-3-yn-2-ol
2a (80 mg, 0.50 mmol), Pd2(dba)3 (11.4 mg, 5 mol%), TBAB (80.5 mg, 0.25 mmol), K2CO3
(138.6 mg, 1 mmol) water (0.5 mL), under microwave irradiation. Purification of the crude
material by silica gel column chromatography (petroleum ether/ethyl acetate, 100:0 to 98:2)
furnished the product 5ba (45.1 mg, 72%) as a colorless compound, [TLC control (petroleum
ether/ethyl acetate 99:01), Rf(4b)=0.8, Rf(5ba)=0.7, UV detection]. IR (MIR-ATR, 4000–600
1
cm-1):
ν
max=2936, 1587, 1473, 1440, 1256, 1178, 1013, 742, 688 cm-1. H NMR (CDCl3, 400
MHz): δ=7.44 (m, 2H, Ar–H), 7.33 (m, 3H, Ar–H), 7.15 (m, 2H, Ar–H), 6.73 (t, J = 7.3 Hz, 1H,
Ar–H), 6.53 (d, J = 7.3 Hz, 1H, Ar–H), 3.47 (d, J = 8.8 Hz ,1H, NCHAHB), 3.30 (m, 2H), 3.12 (d,
13
J = 8.8 Hz ,1H, NCHAHB), 2.69 (s, 2H, CH2), 1.54 (s, 3H, CH3). C NMR (CDCl3, 100 MHz):
δ=151.1, 136.6, 131.6, 128.2, 128.0, 127.6, 123.9, 122.4, 117.4, 107.3, 87.9, 82.1, 64.2, 43.4,
42.5, 31.0, 24.2, 11.8 ppm. HR-MS (ESI+) m/z calculated for [C20H22N]+=[M+H]+: 276.1747;
found 276.1746.
3-[3-(1-Benzyl-3-methyl-2,3-dihydro-1H-indol-3-yl)prop-1-ynyl]aniline (5cg): GP was
carried out with N-benzyl-N-(2-iodophenyl)-N-(2-methylprop-2-enyl)amine 4c (90.7 mg, 0.25
mmol), 4-(3-aminophenyl)-2-methylbut-3-yn-2-ol 2g (87.5 mg, 0.50 mmol), Pd2(dba)3 (11.4 mg,
5 mol%), TBAB (80.5 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol) water (0.5 mL), under
microwave irradiation. Purification of the crude material by silica gel column chromatography
(petroleum ether/ethyl acetate, 100:0 to 97:3) furnished the product 5cg (52.8 mg, 60%) as a
semi solid, [TLC control (petroleum ether/ethyl acetate 99:1), Rf(4c)=0.8, Rf(5cg)=0.7, UV
detection]. IR (MIR-ATR, 4000–600 cm-1):
νmax=3341, 2929, 1589, 1471, 1251, 969, 809, 733,
1
681 cm-1. H NMR (CDCl3, 400 MHz): δ=7.40–7.22 (m, 5H), 7.16 (d, J = 7.3 Hz, 1H), 7.12–
7.02 (m, 2H), 6.78 (dd, J = 7.6 and 1.0 Hz, 1H), 6.75–6.65 (m, 2H), 6.60 (dd, J = 8.1 and 1.1 Hz,
1H), 6.50 (d, J = 7.9 Hz, 1H), 4.36 (d, J = 15.2 Hz, 1H), 4.21 (d, J = 15.2 Hz, 1H), 3.41 (dd, J =
9.0 and 1.2 Hz, 1H), 3.09 (dd, J = 9.0 and 1.2 Hz, 1H), 2.65 (s, 2H), 1.48 (s, 3H). 13C NMR (100
MHz, CDCl3) δ=151.3, 146.0, 138.4, 136.3, 129.1, 128.5, 128.0, 127.7, 127.1, 124.5, 122.6,

122.1, 118.0, 117.7, 114.8, 107.1, 87.1, 82.4, 65.7, 52.9, 43.7, 31.1, 24.3 ppm. HR-MS (ESI+)
m/z calculated for [C25H25N2]+=[M+H]+: 353.2012; found 353.2022.
1-Benzyl-3-[3-(3-fluorophenyl)prop-2-ynyl]-3-methylindoline (5ch): GP was carried out with
N-benzyl-N-(2-iodophenyl)-N-(2-methylprop-2-enyl)amine 4c (90.7 mg, 0.25 mmol), 4-(3-
fluorophenyl)-2-methylbut-3-yn-2-ol 2h (87.5 mg, 0.50 mmol), Pd2(dba)3 (11.4 mg, 5 mol%),
TBAB (80.5 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol) water (0.5 mL), under microwave
irradiation. Purification of the crude material by silica gel column chromatography (petroleum
ether/ethyl acetate, 100:0 to 93:7) furnished the product 5ch (59.4 mg, 67%) as a pale yellow
compound, [TLC control (petroleum ether/ethyl acetate 99:01), Rf(4c)=0.8, Rf(5ch)=0.7, UV
detection]. IR (MIR-ATR, 4000–600 cm-1):
νmax=3033, 1656, 1563, 1469, 1423, 1250, 1081,
1
969, 863, 737 cm-1. H NMR (CDCl3, 400 MHz): δ=7.39–7.29 (m, 4H, Ar–H), 7.28–7.18 (m,
2H, Ar–H), 7.14 (dd, J = 7.3 and 1.5 Hz, 1H, Ar–H), 7.13 (dd, J = 7.3 and 1.5 Hz, 1H, Ar–H),
7.09 (dd, J = 7.8 and 1.5 Hz, 1H, Ar–H), 7.04 (dt, J = 7.8 and 2.5 Hz, 1H, Ar–H), 6.97 (ttt, J =
7.8, 7.8 and 2.5 Hz, 1H, Ar–H), 6.72 (ddd, J = 7.3, 7.3 and 1.0 Hz, 1H, Ar–H), 6.51 (d, J = 7.8
Hz, 1H, Ar–H), 4.37 (d, J = 15.2 Hz, 1H, NCHAHBAr), 4.20 (d, J = 15.2 Hz, 1H, NCHAHBAr),
3.39 (d, J = 8.8 Hz, 1H, NCHAHB), 3.09 (d, J = 8.8 Hz, 1H, NCHAHB), 2.66 (s, 2H, CH2), 1.48
(s, 3H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ=162.3 (d, J = 246.5 Hz), 151.3, 138.3, 136.1,
129.7 (d, J = 8.9 Hz), 128.5, 128.1, 127.7, 127.4 (d, J = 3.0 Hz), 127.1, 125.7 (d, J = 9.5 Hz),
122.6, 118.4 (d, J = 22.6 Hz), 117.7, 115.0 (d, J = 21.2 Hz), 107.2, 88.9, 81.1 (d, J = 2.9 Hz),
65.6, 52.8, 43.6, 40.0, 31.0, 24.2 ppm. HR-MS (ESI+) m/z calculated for [C25H23FN]+=[M+H]+:
356.1809; found 356.1795.
3-[3-(3-Aminophenyl)prop-2-ynyl]-1,3-dimethyl-1,3-dihydro-2H-indol-2-one (7ag): GP was
carried out with N-(2-iodophenyl)-N,2-dimethylacrylamide 6a (75 mg, 0.25 mmol), 4-(3-
aminophenyl)-2-methylbut-3-yn-2-ol 2g (87.5 mg, 0.50 mmol), Pd2(dba)3 (11.4 mg, 5 mol%),
TBAB (80.5 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol) water (0.5 mL), under microwave
irradiation. Purification of the crude material by silica gel column chromatography (petroleum
ether/ethyl acetate, 100:0 to 85:15) furnished the product 7ag (44.2 mg, 61%) as a semi solid,
[TLC control (petroleum ether/ethyl acetate 88:12), Rf(6a)=0.7, Rf(7ag)=0.6, UV detection]. IR
1
(MIR-ATR, 4000–600 cm-1):
ν
max=2929, 1689, 1593, 1470, 1354, 1248, 969, 738, 682 cm-1. H

NMR (CDCl3, 400 MHz): δ=7.48 (dd, J = 7.3 and 1.0 Hz, 1H, Ar–H), 7.29 (ddd, J = 7.8, 7.8 and
1.5 Hz, 1H, Ar–H), 7.08 (ddd, J = 7.8, 7.8 and 1.5 Hz, 1H, Ar–H), 7.02 (d, J = 7.8 Hz, 1H, Ar–
H), 6.85 (d, J = 7.8 Hz, 1H, Ar–H), 6.64–6.53 (m, 2H, Ar–H), 3.21 (s, 3H), 2.88 (d, J = 16.6 Hz,
13
1H), 2.63 (d, J = 16.6 Hz, 1H), 1.50 (s, 3H, CH3) ppm. C NMR (CDCl3, 100 MHz): δ=179.5,
146.1, 143.0, 133.3, 129.1, 128.1, 124.0, 123.4, 122.5, 121.9, 117.8, 114.9, 107.9, 84.8, 83.0,
47.1, 28.8, 26.3, 21.6 ppm. HR-MS (ESI+) m/z calculated for [C19H18KN2O]+=[M+K]+:
329.1051; found 329.1049.
1-Ethyl-3-methyl-3-(3-phenylprop-2-ynyl)-1,3-dihydro-2H-indol-2-one (7ba): GP was
carried out with N-ethyl-N-(2-iodophenyl)-2-methylacrylamide 6b (78.7 mg, 0.25 mmol), 2-
methyl-4-phenylbut-3-yn-2-ol 2a (80 mg, 0.50 mmol), Pd2(dba)3 (11.4 mg, 5 mol%), TBAB
(80.5 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol) water (0.5 mL), under microwave irradiation.
Purification of the crude material by silica gel column chromatography (petroleum ether/ethyl
acetate, 100:0 to 85:15) furnished the product 7ba (52.7 mg, 71%) as a jelly compound, [TLC
control (petroleum ether/ethyl acetate 92:8), Rf(6b)=0.6, Rf(7ba)=0.7, UV detection]. IR (MIR-
ATR, 4000–600 cm-1): max=3024, 1691, 1593, 1469, 1359, 1239, 1091, 1018, 744, 687 cm-1. 1H
ν
NMR (CDCl3, 400 MHz): δ=7.46 (dd, J = 7.3 and 1.0 Hz, 1H, Ar–H), 7.28 (ddd, J = 7.3, 7.3 and
1.5 Hz, 1H, Ar–H), 7.07 (ddd, J = 7.3, 7.3 and 1.5 Hz, 1H, Ar–H), 7.24 (m, 5H, Ar–H), 6.88 (dd,
J = 7.3 and 1.0 Hz, 1H, Ar–H), 3.83 (q, J = 7.3 Hz, 1H, NCHAHBCH3), 3.71 (q, J = 7.3 Hz, 1H,
NCHAHBCH3), 2.90 (d, J = 16.6 Hz, 1H), 2.71 (d, J = 16.6 Hz, 1H), 1.49 (s, 3H, CH3), 1.22 (t, J
= 7.1 Hz, 3H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ=179.0, 142.2, 133.4, 131.5, 128.1,
128.0 127.8, 123.4, 123.3, 108.0, 85.4, 82.6, 47.1, 34.6, 28.8, 21.7, 12.7 ppm. HR-MS (ESI+)
m/z calculated for [C20H20NO]+=[M+H]+: 290.1539; found 290.1540.
1-Benzyl-3-[3-(3-fluorophenyl)prop-2-ynyl]-3-methyl-1,3-dihydro-2H-indol-2-one
(7ch):
GP was carried out with N-benzyl-N-(2-iodophenyl)-N-(2-methylprop-2-enyl)amine 6c (94.2
mg, 0.25 mmol), 4-(3-fluorophenyl)-2-methylbut-3-yn-2-ol 2h (87.5 mg, 0.50 mmol), Pd2(dba)3
(11.4 mg, 5 mol%), TBAB (80.5 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol) water (0.5 mL),
under microwave irradiation. Purification of the crude material by silica gel column
chromatography (petroleum ether/ethyl acetate, 100:0 to 88:12) furnished the product 7ch (62.6
mg, 68%) as a jelly compound, [TLC control (petroleum ether/ethyl acetate 100:0), Rf(6c)=0.6,

Rf(7ch)=0.7, UV detection]. IR (MIR-ATR, 4000–600 cm-1):
νmax=3024, 1692, 1594, 1471,
1
1359, 1241, 1092, 746, 687 cm-1. H NMR (400 MHz, CDCl3) δ=7.41 (dd, J = 7.3 and 0.8 Hz,
1H), 7.26 (dd, J = 5.7 and 4.1 Hz, 2H), 7.24–7.04 (m, 6H), 7.00–6.91 (m, 2H), 6.86–6.78 (m,
1H), 6.74 (d, J = 7.8 Hz, 1H), 5.09 (d, J = 15.2 Hz, 1H), 4.77 (d, J = 15.2 Hz, 1H), 2.97 (d, J =
16.6 Hz, 1H), 2.87 (d, J = 16.6 Hz, 1H), 1.55 (s, 3H) ppm. 13C NMR (100 MHz, CDCl3)
δ=179.5, 163.4, 161.0, 142.3, 135.6, 133.0, 129.7, 129.6, 128.7, 128.6, 128.1, 127.5, 127.5,
127.4, 127.1, 123.1, 122.6, 118.5, 118.3, 115.3, 115.1, 109.1, 86.6, 81.6, 47.4, 43.8, 28.8, 22.5
ppm. HR-MS (ESI+) m/z calculated for [C25H21FNO]+=[M+H]+: 370.1602; found 370.1581.
1,3,5,7-Tetramethyl-3-(3-phenylprop-2-ynyl)-1,3-dihydro-2H-indol-2-one (7da): GP was
carried out with N-(2-iodo-4,6-dimethylphenyl)-N,2-dimethylacrylamide 6d (82.2 mg, 0.25
mmol), 2-methyl-4-phenylbut-3-yn-2-ol 2a (80 mg, 0.50 mmol), Pd2(dba)3 (11.4 mg, 5 mol%),
TBAB (80.5 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol) water (0.5 mL), under microwave
irradiation. Purification of the crude material by silica gel column chromatography (petroleum
ether/ethyl acetate, 100:0 to 90:10) furnished the product 7da (52.9 mg, 70%) as a jelly
compound, [TLC control (petroleum ether/ethyl acetate 90:10), Rf(6d)=0.7, Rf(7da)=0.7, UV
detection]. IR (MIR-ATR, 4000–600 cm-1): max=2940, 1689, 1587, 1445, 1340, 1076, 748 cm-1.
ν
1H NMR (400 MHz, CDCl3) δ=7.34–7.20 (m, 5H), 7.14 (d, J = 0.5 Hz, 1H), 6.89–6.79 (m, 1H),
3.48 (s, 3H), 2.86 (d, J = 16.5 Hz, 1H), 2.65 (d, J = 16.5 Hz, 1H), 2.54 (s, 3H), 2.30 (s, 3H), 1.47
(s, 3H) ppm. 13C NMR (100 MHz, CDCl3) δ=180.2, 138.3, 134.0, 132.2, 131.8, 131.5, 128.2,
127.8, 123.5, 122.0, 119.2, 85.7, 82.7, 46.5, 29.6, 29.2, 22.0, 20.9, 18.8 ppm. HR-MS (ESI+) m/z
calculated for [C21H22NO]+=[M+H]+: 304.1696; found 304.1702.
Acknowledgement
We are grateful to the Department of Science and Technology-Science and Engineering Research
Board (DST-SERB) [NO.:EMR/2017/005312], New Delhi, for financial support. K.R. thanks
MHRD, New Delhi, for the award of a research fellowship.
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‹ [Pd]-Catalysis.
‹ tert-Propargyl alcohols Served as Alkyne Sources
‹ Aqueous Mediated Reaction.
‹ Microwave-assisted Synthesis.
‹ Heterocyclic Compounds have been synthesized.
‹ Environmentally Benign Process.

Declaration of interests
☒ The authors declare that they have no known competing financial interests or personal relationships
that could have appeared to influence the work reported in this paper.
☒The authors declare the following financial interests/personal relationships which may be considered
as potential competing interests:
There are no conflicts to declare.