Synthesis of acetylenic ketones by a Pd-catalyzed carbonylative three-component coupling reaction in [bmim]PF6

Article abstract of DOI:10.1139/v05-031

A carbonylative three-component coupling reaction of aryl iodides with terminal alkynes catalyzed by PdCl₂(PPh₃)₂ was carried out using an ionic liquid, [bmim]PF₆, as the reaction medium, which resulted in good yields of α,β-acetylenic ketones. The low-viscosity ionic liquid, [bmim]NTf₂, was not suitable for this reaction, since the background Sonogashira coupling reaction, a competing reaction, also proceeded.

Full text of DOI:10.1139/v05-031

711
Synthesis of acetylenic ketones by a Pd-catalyzed
carbonylative three-component coupling reaction
1
in [bmim]PF6
Takahide Fukuyama, Ryo Yamaura, and Ilhyong Ryu
Abstract: A carbonylative three-component coupling reaction of aryl iodides with terminal alkynes catalyzed by
PdCl2(PPh3)2 was carried out using an ionic liquid, [bmim]PF6, as the reaction medium, which resulted in good yields
of α,β-acetylenic ketones. The low-viscosity ionic liquid, [bmim]NTf2, was not suitable for this reaction, since the
background Sonogashira coupling reaction, a competing reaction, also proceeded.
Key words: carbonylation, palladium, three-component coupling, ionic liquid, α,β-acetylenic ketones.
Résumé : Nous avons procédé à la préparation, avec de bons rendements, de cétones α,β-acétyléniques. Pour cela,
nous avons réalisé une réaction de couplage à trois composants, catalysée par le PdCl2(PPh3)2 et réalisée dans un mi-
lieu liquide ionique formé de [bmim]PF6, conduisant à la carbonylation des iodures d’aryles. La faible viscosité du li-
quide ionique [bmim]NTf2 n’est pas appropriée pour cette réaction puisque la réaction de couplage de Sonogashira qui
est en compétition avec se produit.
Mots clés : carbonylation, palladium, couplage à trois composants, liquide ionique, cétone α,β-acétylénique.
[Traduit par la Rédaction] Fukuyama et al.
715
Introduction
Two component method
α,β-Acetylenic ketones are useful intermediates for the
synthesis of a variety of important heterocyclic and biologi-
cally active compounds (1). While traditional approaches to
the synthesis of acetylenic ketones relied on the coupling of
a carboxylic acid chloride with a metal acetylide, recent
methods have employed Pd- and (or) Cu-catalyzed coupling
reactions of acid halides and terminal alkynes (eq. [1]) (2).
The carbonylative three-component coupling reaction of aryl
halides with terminal alkynes has also been reported
(eq. [2]) (3). Kobayashi and Tanaka (3a) reported that a
three-component coupling reaction of aryl halides with ter-
minal alkynes and CO can be achieved when PdCl2(dppf) is
used as a catalyst and Et3N as a solvent. Alper and co-
workers (3b) reported that the dimeric palladium hydroxide
[(Ph3P)Pd(Ph)(µ-OH)]2 functions as an efficient catalyst for
a similar three-component coupling reaction. Mohamed Ahmed
and Mori (3c) recently reported on a three-component cou-
pling using PdCl2(PPh3)2 as the catalyst and aqueous NH3
(2 equiv.) as a base with THF as the solvent.
O
O
O
[1]
[2]
M
M
+
R
R
R'
R
X
R'
R'
Three component method
RX CO
+
+
R'
In recent years, ionic liquids have attracted broad atten-
tion in organic synthesis as alternatives to volatile organic
solvents (4), and we previously reported that the Pd-
catalyzed coupling reaction of aryl iodides with terminal al-
kynes — the Sonogashira coupling reaction — proceeds ef-
fectively in an ionic liquid, 1-butyl-3-methylimidazolium
hexafluorophosphate ([bmim]PF6), without the need for a
copper co-catalyst (5). We also reported that a low-viscosity
ionic liquid, [bmim]NTf2, is an excellent reaction medium
for Pd-catalyzed Mizoroki–Heck, Suzuki–Miyaura, and Stille
coupling reactions (6). Herein we report on the carbonylative
three-component coupling reaction of an aryl iodide with
terminal alkynes, which proceeds smoothly when [bmim]PF6
is used as the reaction medium (7).
Received 9 December 2004. Published on the NRC Research
Press Web site http://canjchem.nrc.ca on 23 June 2005.
This paper is dedicated to Professor Howard Alper.
T. Fukuyama, R. Yamaura, and I. Ryu.2 Department of
Chemistry, Graduate School of Sciences, Osaka Prefecture
University, Sakai, Osaka 599-8531, Japan.
Results and discussion
When iodobenzene (1a) was treated with phenylacetylene
(2a, 1.2 equiv.) and pressurized CO (20 atm (1 atm =
101.325 kPa)) in the presence of 1 mol% PdCl2(PPh3)2 and
Et3N (3.6 equiv.) in [bmim]PF6 at 120 °C for 1 h, the reac-
1This article is part of a Special Issue dedicated to Professor
Howard Alper.
2Corresponding author (e-mail: ryu@c.s.osakafu-u.ac.jp).
Can. J. Chem. 83: 711–715 (2005)
doi: 10.1139/V05-031
© 2005 NRC Canada

712
Can. J. Chem. Vol. 83, 2005
Table 1. Pd-catalyzed carbonylative coupling reaction of 1a with 2a.
O
Pd cat. (1 mol%)
Ph
1a
I
CO
Ph
Ionic liquid
Et3N, 120 °C, 1 h
Ph
Ph
2a
3a
Et3N
(equiv.)
Entry
Pd
CO (atm)
Ionic liquid
[bmim]PF6
[bmim]NTf2
[bmim]PF6
[bmim]PF6
[bmim]PF6
[bmim]PF6
[bmim]PF6
[bmim]PF6
Yield (%)a,b
1
2
3
4
5
6
7c
8
PdCl2(PPh3)2
PdCl2(PPh3)2
PdCl2
20
20
20
20
20
20
20
10
3.6
3.6
3.6
3.6
3.6
3.6
2.0
3.6
82
58 (24)
60
PdCl2(CH3CN)2
Pd(OAc)2
62
60
Pd(PPh3)4
63 (13)
48
PdCl2(PPh3)2
PdCl2(PPh3)2
52 (21)
Note: Reaction conditions: 1a (1 mmol), 2a (1.2 mmol), Pd-catalyst (1 mol%), ionic liquid (3 mL), 120 °C, 1 h.
aIsolated yields by chromatography on SiO2.
bYield of diphenylacetylene is shown in parentheses.
cReaction was carried out for 2 h.
tion proceeded smoothly to give the acetylenic ketone 3a in
82% yield (Table 1, entry 1). The reaction was clean, and
diphenylacetylene, the noncarbonylated product of the
Sonogashira coupling reaction, was not observed. Mohamed
Ahmed and Mori (3c) previously reported that the reaction
proceeded smoothly with aqueous NH3 as a base. However,
when aqueous NH3 was used as a base in the present system,
Michael addition of NH3 to 3a became a major reaction
course. We also examined a low-viscosity ionic liquid,
[bmim]NTf2 (6); however, in this case, the background
Sonogashira coupling reaction competed under the condi-
tions employed (entry 2). Reactions using other Pd(II) com-
plexes such as PdCl2, PdCl2(CH3CN)2, and Pd(OAc)2 were
sluggish, and significant amounts of unreacted 1a were re-
covered (entries 3–5). When Pd(PPh3)4 was used as the cata-
lyst, the Sonogashira coupling reaction competed, giving
diphenylacetylene (entry 6). Reducing the amount of amine
from 3.6 equiv. to 2 equiv. resulted in lower conversions
even when the reaction time was prolonged (2 h) (entry 7).
When the reaction was carried out at reduced CO pressure
(10 atm), the Sonogashira coupling reaction competed again
(entry 8).
intact (entries 4–6). The reaction of 1-iodonaphthalene (1h)
and 2-iodothiophene (1i) with 2a also gave carbonylated
products 3h and 3i, respectively (entries 7 and 8). Both p-
acetylphenylacetylene and p-methoxyphenylacetylene could
be used in this reaction (entries 9 and 10). The reaction of
tert-butylacetylene (2d) gave the coupling product 3l in rela-
tively low yield, but when N-methylpiperidine was em-
ployed as a base, the yield was increased to 76% (entry 11).
When the reaction of 1a with 2-methyl-3-butyne-2-ol (2e)
was carried out using N-methylpiperidine as the base, 3-
furanone 4 was obtained as the major product (eq. [3]) (8).
An experiment using milder reaction conditions (100 °C,
10 atm) gave a mixture of acetylenic ketone 3m and 4.
When the isolated 3m was exposed to the same reaction sys-
tem, furanone 4 was formed, suggesting that the initially
formed 3m served as the precursor for 4 (9).
It is well known that imidazolium-based ionic liquids re-
act with Pd complexes to give Pd N-heterocyclic carbene
complexes, which are thought to be the key catalyst species
in many reactions in which a Pd–ionic liquid system is used
(10). This may also be true for the present system, since the
Pd carbene complex (which contains one imidazolylidene,
one triphenylphosphine, and two chlorine ligands (6))
readily catalyzed the reaction of 1a with 2a to give 3a in
73% yield (eq. [4]). We also investigated the reusability of
the catalyst and the reaction medium for this reaction sys-
tem. Both the catalyst and the reaction medium can be re-
used but with a slight decrease in efficiency (Scheme 1).
Some results for reactions in which various aryl iodides
and terminal alkynes were used are shown in Table 2. The
reaction of substituted aryl iodides gave the corresponding
acetylenic ketones in good yields (entries 1–6). Iodoben-
zenes containing a halogen atom (Br, Cl, or F) at the 4-
position gave the coupling products, with the halogen atoms
O
PdCl2(PPh3)2 (1 mol%)
OH
O
Ph
CO
Ph
I
O
[bmim]PF6
OH
+
[3]
Ph
N-methylpiperidine
1a
2e
120 °C, 1 h, 20 atm
100 °C, 1 h, 10 atm
3m trace
3m 32%
4 56%
7%
4
© 2005 NRC Canada

Fukuyama et al.
713
Table 2. PdCl2(PPh3)2-catalyzed carbonylative coupling reaction
Scheme 1. Recycling of the Pd catalyst and [bmim]PF6 and
of aryl iodides with terminal alkynes in [bmim]PF6.
workup process (1 atm = 101.325 kPa).
O
O
PdCl2(PPh3)2 (1 mol%)
PdCl2(PPh3)2 (1 mol%)
Ar
I
+
+
CO
Ar
Ph
R
CO
Ph
1a
I
[bmim]PF6, NEt3
[bmim]PF6, Et3N
Ph
2a
R
Ph
1
2
3
120 °C, 1 h, 20 atm
20 atm, 120 °C, 1 h
3a
Entry
1
1
Alkyne 2
Product 3
Yield (%)a
Ar
I
1
3
Run
2
82
61
Yield(%)
68
O
I
82
82
Ph
Ph
1b
2a
3b
Et2O
3a
H2O
Et3N·HI
O
I
Et2O
H2O
3a
2
2a
Et3N·HI
Et3N·HI
Pd-cat.
MeO
next run
Ph
Ph
Ph
Ph
Pd-cat.
MeO
Pd-cat.
[bmim]PF6
3c
[bmim]PF6
[bmim]PF6
1c
1d
O
I
Reaction mixture
3
4
2a
2a
78
76
O
3d
N
N
O
Bu
O
I
I
Ph3P Pd Cl
Cl
[4]
O
Br
(1 mol%)
Br
Ph
1e
3e
CO
Ph
I
[bmim]PF6, Et3N
Ph
2a
Ph
O
120 °C, 1 h, 20 atm
5
79
81
2a
2a
2a
1a
3a 73%
Cl
Cl
1f
3f
O
Conclusions
I
6
The findings herein show that when using [bmim]PF6 as a
reaction medium, the Pd-catalyzed carbonylative three-
component coupling reaction of aryl iodides with terminal
alkynes proceeds efficiently to give α,β-acetylenic ketones in
good yields. The low-viscosity ionic liquid, [bmim]NTf2,
which is an excellent reaction medium for typical Pd-
catalyzed coupling reactions, is not suitable for the present
reaction because of the competing Sonogashira coupling re-
action.
F
Ph
F
1g
3g
O
7b
I
78
Ph
Ph
3h
1h
O
S
S
I
8
2a
78
80
1i
3i
O
Experimental section
Ph
9b
Ph
I
O
3j
General information
1a
1a
2b
1H NMR spectra were recorded on a JEOL JMN-AL400
(400 MHz) spectrometer in CDCl3. Chemical shifts are re-
ported in parts per million (δ) downfield from internal
tetramethylsilane. 13C NMR spectra were recorded with a
JEOL JMN-AL400 (100 MHz). Infrared spectra were ob-
tained on a JASCO FT/IR-4100 spectrometer; absorptions
are reported in reciprocal centimeters. Mass spectra were ob-
tained on a Shimadzu GCMS-QP 5050A instrument. High
resolution mass spectra were recorded with a JEOL MS700
spectrometer. Coupling products were purified by flash chro-
matography on silica gel (nacalai tesque, Silica Gel 60,
230–400 mesh) and, if necessary, were further purified by
recycling preparative HPLC (JAI LC-908) equipped with a
GPC column and using CHCl3 as eluant. All products, ex-
cept for 3j, were known compounds and were identified by
comparison with literature data.
O
O
O
10
80
76
Ph
Ph
OMe
3k
3l
2c
2d
OMe
11c
1a
Note: Reaction conditions: 1 (1 mmol), 2 (1.2 mmol), PdCl2(PPh3)2
(1 mol%), [bmim]PF6 (3 mL), Et3N (3.6 mmol) 120 °C, 1 h.
aIsolated yields after chromatography on SiO2.
bReaction carried out under 30 atm of CO.
cN-Methylpiperidine was used as the base.
© 2005 NRC Canada

714
Can. J. Chem. Vol. 83, 2005
94.11, 119.55, 128.28, 128.62, 129.50, 130.98, 133.01,
139.61, 140.62, 176.87, 197.20. EI-MS m/z (rel intensity):
248 ([M]+, 67), 233 (100), 205 (34), 177 (20), 176 (33), 129
(71), 103 (27), 75 (28).
Typical procedure for the PdCl2(PPh3)2-catalyzed three-
component coupling reaction
A magnetic stirring bar, [bmim]PF6 (3 mL), PdCl2(PPh3)2
(0.01 mmol, 7 mg), iodobenzene (1a) (1 mmol, 204 mg),
Et3N (3.6 mmol, 0.5 mL), and phenylacetylene 2a (1.2 mmol,
122 g) were placed in a 50 mL stainless autoclave lined with
a glass liner. The autoclave was closed, purged three times
with 10 atm of carbon monoxide, pressurized to 20 atm with
CO, and then heated at 120 °C for 1 h. Excess CO was dis-
charged at room temperature. The product was extracted
from the reaction mixture by the addition of Et2O (5 mL),
followed by decantation of the ether solution of the product.
This was repeated an additional four times. The residue was
purified by flash chromatography on silica gel (eluant hex-
ane : EtOAc = 10:1) to give 166 mg (82%) of 3a.
1-(4-Bromophenyl)-3-phenyl-2-propynone (3e) (3b)
A white solid. mp 106 to 107 °C (lit. (3b) value mp 106 to
1
107 °C). IR (KBr) (cm–1): 2199, 1651. H NMR (400 MHz,
CDCl3) δ: 7.41–7.46 (m, 2H), 7.48–7.52 (m, 1H), 7.65–7.69
(m, 4H), 8.06–8.09 (m, 2H). 13C NMR (100 MHz, CDCl3) δ:
86.68, 93.78, 119.94, 128.83, 129.65, 131.01, 131.08,
132.07, 133.20, 135.77, 176.85. EI-MS m/z (rel intensity):
285 ([M]+, 41), 284 (40), 258 (54), 256 (57), 176 (41), 129
(100), 88 (32), 75 (37), 51 (20).
1-(4-Chlorophenyl)-3-phenyl-2-propynone (3f) (3b)
A white solid. mp 104 to 105 °C (lit. (3b) value mp
Recycling of Pd catalyst and [bmim]PF6
1
104 °C). IR (KBr) (cm–1): 2199, 1654. H NMR (400 MHz,
After the reaction, the product was extracted from the re-
action mixture with Et2O (5 × 5 mL), and ammonium salts
were removed by extraction with water (5 × 5 mL). Both the
Et2O and water were degassed by N2 bubbling prior to use.
Excess Et2O and water were removed under reduced pres-
sure, and the remaining ionic liquid layer, containing the Pd
catalyst, was used in the next run.
CDCl3) δ: 7.40–7.45 (m, 2H), 7.46–7.52 (m, 3H), 7.66–7.69
(m, 2H), 8.13–8.16 (m, 2H). 13C NMR (100 MHz, CDCl3) δ:
86.68, 93.69, 119.98, 129.04, 129.07, 130.93, 131.05,
133.16, 135.41, 140.76, 176.66. EI-MS m/z (rel intensity):
240 ([M]+, 55), 214 (31), 212 (100), 176 (33), 129 (83), 75
(43), 51 (21).
1-(4-Fluorophenyl)-3-phenyl-2-propynone (3g) (12)
1,3-Diphenyl-2-propynone (3a) (3b)
A white solid. mp 100–102 °C. IR (KBr) (cm–1): 2206,
A white solid. mp 46–48 °C (lit. (3b) value mp 46 to
1
1634. H NMR (400 MHz, CDCl3) δ: 7.15–7.21 (m, 2H),
47 °C). IR (KBr) (cm–1): 2199, 1641. H NMR (400 MHz,
1
7.40–7.45 (m, 2H), 7.47–7.51 (m, 1H), 7.66–7.69 (m, 2H),
8.22–8.27 (m, 2H). 13C NMR (100 MHz, CDCl3) δ: 86.68,
93.45, 115.97 (J = 22.1 Hz), 120.03, 128.81, 131.01, 132.32
(J = 9.6 Hz), 133.15, 133.49, 166.53 (J = 257.2 Hz), 176.45.
EI-MS m/z (rel intensity): 224 ([M]+, 41), 196 (100), 129
(52), 75 (23).
CDCl3) δ: 7.40–7.44 (m, 2H), 7.46–7.54 (m, 3H), 7.61–7.65
(m, 1H), 7.67–7.71 (m, 2H), 8.20–8.25 (m, 2H). 13C NMR
(100 MHz, CDCl3) δ: 86.80, 93.01, 119.98, 128.52, 129.44,
130.70, 132.94, 134.01, 136.77, 177.86. EI-MS m/z (rel in-
tensity): 206 ([M]+, 45), 178 (100), 129 (46), 51 (23).
1-(2-Tolyl)-3-phenyl-2-propynone (3b) (11)
1-(1-Naphthyl)-3-phenyl-2-propynone (3h) (2c)
1
A colorless oil. IR (neat) (cm–1): 2197, 1638. H NMR
A white solid. mp 94 to 95 °C (lit. (2c) value mp 95 °C).
1
IR (KBr) (cm–1): 2195, 1634. H NMR (400 MHz, CDCl3)
(400 MHz, CDCl3) δ: 2.67 (s, 3H), 7.25–7.30 (m, 1H), 7.36–
7.48 (m, 5H), 7.64–7.68 (m, 2H), 8.28–8.32 (m, 1H). 13C
NMR (100 MHz, CDCl3) δ: 21.81, 88.28, 91.65, 120.18,
125.77, 128.50, 130.45, 132.03, 132.75, 133.03, 135.55,
140.28, 179.54. EI-MS m/z (rel intensity): 220 ([M]+, 26),
219 (100), 191 (72), 189 (21), 131 (23), 91 (21). HR-MS
(EI) m/z calcd. for C16H12O: 220.0888 ([M]+); found:
220.0894.
δ: 7.40–7.44 (m, 2H), 7.46–7.50 (m, 1H), 7.56–7.62 (m,
2H), 7.66–7.72 (m, 3H), 7.90–7.93 (m, 1H), 8.08–8.12 (m,
1H), 8.63–8.66 (m, 1H), 9.21–9.25 (m, 1H). 13C NMR
(100 MHz, CDCl3) δ: 88.63, 91.82, 120.44, 124.60, 126.10,
126.88, 128.78, 129.07, 130.74, 130.84, 133.02, 133.05,
133.97, 134.69, 135.25, 179.83. EI-MS m/z (rel intensity):
256 ([M]+, 100), 228 (50), 226 (47), 202 (21), 129 (35), 114
(35), 113 (33), 101 (15), 75 (21), 51 (21).
1-(4-Metoxyphenyl)-3-phenyl-2-propynone (3c) (3b)
A white solid. mp 96–98 °C (lit. (3b) value mp 97 to
3-Phenyl-1-(2-thiophenyl)-2-propynone (3i) (13)
1
98 °C). IR (KBr) (cm–1): 2199, 1630. H NMR (400 MHz,
1
A colorless oil. IR (neat) (cm–1): 2199, 1616. H NMR
CDCl3) δ: 3.89 (s, 3H), 6.96–7.00 (m, 2H), 7.39–7.43 (m,
2H), 7.45–7.50 (m, 1H), 7.65–7.69 (m, 2H), 8.16–8.21 (m,
3H). 13C NMR (100 MHz, CDCl3) δ: 55.38, 86.74, 92.09,
113.71, 120.08, 128.47, 130.04, 130.43, 131.73, 132.73,
164.30, 176.37. EI-MS m/z (rel intensity): 236 ([M]+, 79),
209 (20), 208 (100), 193 (95), 165 (53), 129 (42), 75 (20).
(400 MHz, CDCl3) δ: 7.17–7.20 (m, 2H), 7.40–7.44 (m,
2H), 7.46–7.51 (m, 1H), 7.64–7.68 (m, 2H), 7.72–7.74 (m,
1H), 8.00–8.02 (m, 1H). 13C NMR (100 MHz, CDCl3) δ:
86.34, 91.61, 119.71, 128.25, 128.56, 130.74, 132.87,
135.00, 135.18, 144.74, 169.60. EI-MS m/z (rel intensity):
212 ([M]+, 46), 184 (100), 129 (26).
1-[4-(1-Oxoethyl)phenyl]-3-phenyl-2-propynone (3d) (3c)
A white solid. mp 101 to 102 °C (lit. (3c) value mp 103 to
104 °C). IR (KBr) (cm–1): 2197, 1684, 1634. 1H NMR
(400 MHz, CDCl3) δ: 2.66 (s, 3H), 7.42–7.46 (m, 2H), 7.49–
7.53 (m, 1H), 7.69–7.72 (m, 2H), 8.06–8.10 (m, 2H), 8.28–
8.32 (m, 2H). 13C NMR (100 MHz, CDCl3) δ: 26.79, 86.64,
3-[4-(1-Oxoethyl)phenyl]-1-phenyl-2-propynone (3j)
A white solid. mp 115 to 116 °C. IR (KBr) (cm–1): 2202,
1
1684, 1642. H NMR (400 MHz, CDCl3) δ: 2.64 (s, 3H),
7.51–7.56 (m, 2H), 7.63–7.68 (m, 1H), 7.76–7.79 (m, 2H),
7.98–8.02 (m, 2H), 8.20–8.23 (m, 2H). 13C NMR (100 MHz,
CDCl3) δ: 26.75, 88.80, 91.23, 124.71, 128.45, 128.81,
© 2005 NRC Canada

Fukuyama et al.
715
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1
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Wasserscheid and W. Keim. Angew. Chem. Int. Ed. 39, 3772
(2000); (c) C.M. Gordon. Appl. Catal. A, 222, 101 (2001);
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102, 3667 (2002); (e) T. Fukuyama and I. Ryu. J. Synth. Org.
Chem. Jpn. 63, 503 (2005).
CDCl3) δ: 3.86 (s, 3H), 6.92–6.94 (m, 2H), 7.48–7.53 (m,
2H), 7.60–7.66 (m, 3H), 8.20–8.24 (m, 2H). 13C NMR
(100 MHz, CDCl3) δ: 55.50, 86.99, 94.45, 111.92, 114.54,
128.66, 129.54, 134.00, 135.21, 137.13, 161.85, 178.08. EI-
MS m/z (rel intensity): 236 ([M]+, 100), 208 (53), 193 (58),
165 (31), 159 (94), 77 (20), 51 (20).
4,4-Dimethyl-1-phenyl-2-pentyn-1-one (3l) (3b)
1
A colorless oil. IR (neat) (cm–1): 2211, 1649. H NMR
(400 MHz, CDCl3) δ: 1.38 (s, 9H), 7.44–7.52 (m, 2H), 7.56–
7.62 (m, 1H), 8.10–8.14 (m, 2H). 13C NMR (100 MHz,
CDCl3) δ: 28.13, 30.26, 78.19, 104.04, 128.55, 129.58,
133.90, 137.09, 178.44. EI-MS m/z (rel intensity): 186
([M]+, 25), 143 (50), 128 (30), 105 (100), 77 (35), 51 (22).
4-Hydroxy-4-methyl-1-phenyl-2-pentyn-1-one (3m) (3b)
1
A colorless oil. IR (neat) (cm–1): 2212, 1645. H NMR
(400 MHz, CDCl3) δ: 1.67 (s, 6H), 7.46–7.51 (m, 2H), 7.59–
7.64 (m, 1H), 8.10–8.14 (m, 2H). 13C NMR (100 MHz,
CDCl3) δ: 30.69, 65.22, 79.81, 98.27, 128.55, 129.58,
134.22, 136.41, 178.02. EI-MS m/z (rel intensity): 188
([M]+, 8), 173 (100), 145 (22), 105 (27), 95 (22), 77 (44), 53
(70), 51 (33).
5. T. Fukuyama, M. Shinmen, S. Nishitani, M. Sato, and I. Ryu.
Org. Lett. 4, 1691 (2002).
6. S. Liu, T. Fukuyama, M. Sato, and I. Ryu. Synlett, 1814
(2004).
7. For examples of carbonylation reaction in ionic liquids, see:
(a) E. Mizushima, T. Hayashi, and M. Tanaka. Green Chem. 3,
76 (2001); (b) K. Qiao and Y.Q. Deng. New J. Chem. 26, 667
(2002); (c) C. Hardacre, J.D. Holbrey, S.P. Katdare, and K.R.
Seddon. Green Chem. 4, 143 (2002).
8. It was reported that a transition metal catalyzed reaction of 1a,
CO, and 2e in the presence of CO2 gave furanone 4, see: Y.
Inoue, K. Ohuchi, I.-F. Yen, and S. Imaizumi. Bull. Chem.
Soc. Jpn. 62, 3518 (1989).
9. For similar transformation, see: (a) H. Saimoto, M. Shinoda,
S. Matsubara, K. Oshima, T. Hiyama, and H. Nozaki. Bull.
Chem. Soc. Jpn. 56, 3088 (1983); (b) K.-W. Lee, Y.H. Choi,
Y.H. Joo, J.K. Kim, S.S. Shin, Y.J. Byun, Y. Kim, and S.
Chung. Bioorg. Med. Chem. 10, 1137 (2002).
10. (a) L. Xu, W. Chen, and J. Xiao. Organometallics, 19, 1123
(2000); (b) F. McLachlan, C.J. Mathews, P.J. Smith, and T.
Welton. Organometallics, 22, 5350 (2003); also see reviews on
C-C coupling reactions catalyzed by Pd N-heterocyclic
carbene complex: (c) W.A. Herrmann, K. Öfele, D. Von
Preysing, and S.K. Schneider. J. Organomet. Chem. 687, 229
(2003); (d) A.C. Hillier, G.A. Grasa, M.S. Viciu, H.M. Lee, C.
Yang, and S.P. Nolan. J. Organomet. Chem. 653, 69 (2002).
11. A. Arcadi, S. Cacchi, F. Marinelli, P. Pace, and G. Sanzi.
Synlett, 823 (1995).
2,2-Dimethyl-5-phenyl-3(2H)-furanone (4) (14)
A yellow oil. IR (neat) (cm–1): 3103, 1694. 1H NMR
(400 MHz, CDCl3) δ: 1.48 (s, 6H), 5.96 (s, 1H), 7.45–7.50
(m, 2H), 7.52–7.56 (m, 1H), 7.80–7.85 (m, 2H). 13C NMR
(100 MHz, CDCl3) δ: 23.22, 88.99, 98.61, 127.22, 128.89,
129.20, 132.67, 183.49, 206.99. EI-MS m/z (rel intensity):
188 ([M]+, 20), 102 (100).
Acknowledgment
IR thanks a Grant-in-Aid for Scientific Research on Prior-
ity Areas (A) “Reaction Control of Dynamic Complexes”
from the Ministry of Education, Culture, Sports, Science and
Technology, Japan, for financial support. This work was sup-
ported, in part, by a Dainippon Ink and Chemicals Inc.
Award in Synthetic Organic Chemistry, Japan, granted to TF.
This work was financially supported by the Highly Efficient
Micro Chemical Process Technology Project of NEDO.
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