New light on an old reaction: Phase-transfer-catalyzed intramolecular cyclization of propargyl compounds for synthesis of indene derivatives and disubstituted benzo[b]furans

Article abstract of DOI:10.1016/j.tet.2011.12.055

A variety of indene derivatives and disubstituted benzo[b]furans are readily prepared under the mild reaction condition from propargylic compounds by phase-transfer catalysis (PTC) instead of metal catalysis.

Full text of DOI:10.1016/j.tet.2011.12.055

Tetrahedron 68 (2012) 1367e1370
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New light on an old reaction: phase-transfer-catalyzed intramolecular cyclization
of propargyl compounds for synthesis of indene derivatives and disubstituted
benzo[b]furans
*
Peng-Shuai Sun, Jie Hu, Xiang-Chuan Wang, Lei Liu, Yong-Min Liang
State Key Laboratory of Applied Organic Chemistry, Lanzhou University, TianShui South Road 222, Lanzhou 730000, People’s Republic of China
a r t i c l e i n f o
a b s t r a c t
Article history:
A variety of indene derivatives and disubstituted benzo[b]furans are readily prepared under the mild
reaction condition from propargylic compounds by phase-transfer catalysis (PTC) instead of metal
catalysis.
Received 29 September 2011
Received in revised form 12 December 2011
Accepted 20 December 2011
Available online 24 December 2011
Ó 2011 Elsevier Ltd. All rights reserved.
Keywords:
Phase-transfer-catalyzed
Propargylic carbonates
Allenes
Indene
Benzo[b]furans
[M]
1. Introduction
CO2Et
CO2Et
OR3
R1 R2
CO2Et
CO2Et
[M] = Pd, Ni
Allenes, an important class of unsaturated hydrocarbons, have
received considerable attention in recent years.1e3,12 As a result,
a number of routes leading to differently substituted allenes have
been described in the literature.4e12 Among our efforts in the area
of allene chemistry,13e15 we have demonstrated an efficient syn-
thetic route to allenyl indene derivatives via the Palladium or
Nickel-catalyzed reaction of propargylic carbonates with carbon
nucleophiles (Scheme 1). Compared with metal-catalyzed
methods, phase-transfer catalysis has long been recognized as
a versatile methodology for organic synthesis in both industrial and
academic laboratories, featuring its simple reaction procedure, safe,
inexpensive, environmentally friendly reagents, absence of anhy-
drous solvents, ease of scale-up, and metal-free conditions.16 Re-
cently, we have reported the addition of carbon nucleophiles to
alkynes by phase-transfer catalysis.17 In this test, we report a new
mild synthesis of allenyl indene derivatives and disubstituted
benzo[b]furans by PTC. To the best of our knowledge, this is the first
report about the synthesis of allenyl indene derivatives under
metal-free condition.
[PTC]
R2
This work
R1
O
[M]
O
R1
O
O
[M] = Pd
R1
R
[PTC]
R
This work
OCO2Et
Ph
Ph
Ph
Ph
Ph
P
Ph
P
Br
Cl
Br
Br
P
Ph
Ph
Ph
Ph
PTC-3
PTC-2
PTC -1
Scheme 1. Transition metal-catalyzed or phase-transfer-catalyzed intramolecular cy-
clization of propargylic compounds.
2. Results and discussion
Initially, we focused on the reaction of 0.20 mmol of 3-(2-(2,2-
di(ethoxycarbonyl)ethyl)phenyl)prop-2-ynyl methyl carbonate
(1a), 5 mol % of PTC-1, and 2 equiv of K2CO3 in DMF at 60 ꢀC in air. To
our delight, the desired product 2a was formed in 66% yield with
high regioselectivity after 1.2 h (Table 1, entry 1). Encouraged by this
result, we further optimized the reaction conditions. Other common
* Corresponding author. Tel.: þ86 931 891 2593; fax: þ86 931 891 2582; e-mail
address: liangym@lzu.edu.cn (Y.-M. Liang).
0040-4020/$ e see front matter Ó 2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2011.12.055

1368
P.-S. Sun et al. / Tetrahedron 68 (2012) 1367e1370
such as propargylic carbonates, acetate, benzoate, and phosphate
Table 1
gave the desired products in excellent yields (Table 2, entries 1e5),
while the propargylic bromide gave the poor yield (entry 6). This
indicated that the activity of the reaction has a great dependence on
the leaving group. Next the reaction of substituted secondary and
tertiary propargyl substrates were investigated. Secondary carbon-
ates possessing various substituents (aryl- substituted and hetero-
cyclic-) at the propargylic position also worked well, and afforded
the corresponding products in moderate yields (entries 7e13).
Functional groups, such as methyl, methoxyl, chloro, bromo were
well tolerated in the reaction. The secondary carbonate, having
methyl substituent, produced high yield of the indene derivative
(entry 14). Meanwhile, the reaction of tertiary propargylic acetate
has also been studied in our system and the expected product has
been obtained although the result was not very good (entry 15).
Very recently, we have reported a convenient approach to the
synthesis of a variety of 2-aroyl(acyl, or carboxyl)-3-vinyl benzo[b]
furans via Pd/C-catalyzed carboannulation of propargylic com-
pounds. We expected to investigate these substrates using our PTC
instead of the palladium. Fortunately, the cyclization/isomerization
products were obtained and the yields were comparable with the
latter under the optimized conditions (Table 3, entries 1e7). It is
noteworthy that Cs2CO3 alone did not cyclize the reaction, only the
combination of base and PTC could take place.
Optimization of the phase-transfer-catalyzed intramolecular cyclization of 1aa
CO2Et
CO2Et
[PTC], base
CO2Et
solvent, 60 oC
CO2Et
2a
1a
OCO2Me
Entry
[PTC]
Base
Solvent
DMF
DMF
DMF
CH3CN
THF
DMF
DMF
DMF
DMF
DMF
DMF
Time (h)
Yield (%)
1
2
3
4
5
6
7
8
PTC-1
PTC-1
PTC-1
PTC-1
PTC-1
PTC-2
PTC-3
TBAB
TBAC
TEAI
K2CO3
1.2
1.5
0.8
0.8
5.5
0.8
0.8
1
70
73
93
92
58
87
84
86
87
90
80
Na2CO3
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
9
10
11
1
1
1
TEAI
a
Reactions were carried out on a 0.2 mmol scale in 2.0 mL of solvent in air at 60 ꢀ
C
with 1.0 equiv of 1a, 2.0 equiv of base, and 5 mol % equiv of PTC.
bases, such as Na2CO3, Cs2CO3 were also tested; Cs2CO3 gave the
better yield of 93% (entries 2 and 3). The effect of the solvent was also
investigated. Changing the solvent to THF, CH3CN failed to improve
the yield of the product 2a (entries 4 and 5). When different PTCs
were examined, the results showed that PTC-2 and PTC-3 could also
promote this cyclization, but the desired product 2a was only ob-
tained with 87% and 84% yield, respectively (entries 6 and 7). Tet-
raalkyl ammonium salts, such as Et4NI, Bu4NBr, Bu4NCl, and Bu4NF
have also been applied to this process, and the yields were not better
than PTC-1 (entries 8e11). Thus, we chose the following reaction
conditions as optimum for all subsequent cyclization: 0.20 mmol of
1a, 5 mol % PTC-1, and 0.40 mmol Cs2CO3 in DMF at 60 ꢀC in air.
With the optimized conditions in hand, the breadth and scope of
this reaction was then investigated, and the results are summarized
in Table 2. The reactions of different substituted primary propargylic
compounds were investigated first. All of the propargylic substrates,
Table 3
Synthesis of 2-aroyl-3-vinyl benzo[b]furans catalyzed by PTC-1a
O
O
5 mol % PTC-1
2 equiv. Cs2CO3
DMF, 60 oC
R1
O
O
R1
R
R
4a-f
3a-f
OCO2Et
Entry
Substrate 3
Product 4
Time (h)
Yieldb (%)
1
2
3
4
5
6
7
R¼H, R1¼Ph, 3a
4a
4b
4c
4d
4e
4f
1
1
1
1
3
3
6
82
84
86
80
94
90
60
R¼CH3, R1¼Ph, 3b
R¼t-Bu, R1¼Ph, 3c
R¼Cl, R1¼Ph, 3d
R¼H, R1¼CH3, 3e
R¼t-Bu, R1¼CH3, 3f
R¼Cl, R1¼OEt, 3g
4g
Table 2
Synthesis of allenyl indene derivatives catalyzed by PTC-1a
a
Reactions were carried out on a 0.2 mmol scale in 2.0 mL of DMF in air at 60 ꢀ
C
with 1.0 equiv of 3, 2.0 equiv of Cs2CO3, and 5 mol % equiv of PTC-1.
CO2Et
CO2Et
CO2Et
5 mol % PTC-1
2 equiv. Cs2CO3
b
Isolated yields.
CO2Et
DMF, 60 oC
R3
3. Conclusion
R2
R1
R2
2a-o R1
1a-o
In conclusion, we have demonstrated for the first time that
phase-transfer-catalyzed cyclization of propargylic compounds is
a novel and efficient method for synthesis of allenyl indene de-
rivatives and disubstituted benzo[b]furans. These reactions are run
under mild conditions, tolerate various functional groups, and
generally provide the desired products in moderated to good yields.
Compared to the expensive transitionmetal-catalyzed reaction, the
process showed considerable synthetic advantages in terms of mild
reaction condition, environmentally friendly, and low cost. The
scope, mechanism, and synthetic applications of this reaction are
currently under investigation.
Entry Substrate 1
Product 2 Time (h) Yieldb (%)
1
2
3
4
5
6
7
8
R1¼R2¼H, R3¼OCO2CH3 1a
R1¼R2¼H, R3¼OCO2Et 1b
R1¼R2¼H, R3¼OAc 1c
2a
2a
2a
2a
2a
2a
2g
0.8
0.8
0.8
0.8
0.8
1.2
1
1
1.5
2
2
2
2
1.5
5
93
90
80
93
83
38
70
72
65
60
62
65
60
93
46
R1¼R2¼H, R3¼OCOPh 1d
R1¼R2¼H, R3¼PO(OEt)2 1e
R1¼R2¼H, R3¼Br 1f
R1¼H, R2¼Ph, R3¼OCO2Et 1g
R1¼H, R2¼p-CH3C6H4, R3¼OCO2Et 1h 2h
9
R1¼H, R2¼p-ClC6H4, R3¼OCO2Et 1i
R1¼H, R2¼p-BrC6H4, R3¼OCO2Et 1j
2i
2j
10
11
12
13
14
15
R1¼H, R2¼m-CH3C6H4, R3¼OCO2Et 1k 2k
R1¼H, R2¼o-OCH3C6H4, R3¼OCO2Et 1l 2l
4. Experimental
R1¼H, R2¼2-furyl, R3¼OCO2Et 1m
R1¼H, R2¼CH3, R3¼OCO2Et 1n
R1¼R2¼Ph, R3¼OAc 1o
2m
2n
2o
4.1. General methods
a
Reactions were carried out on a 0.2 mmol scale in 2.0 mL of DMF in air at 60 ꢀ
C
All reactions under standard conditions were monitored by
thin-layer chromatography (TLC) on gel GF254 plates. The silica gel
with 1.0 equiv of 1, 2.0 equiv of Cs2CO3, and 5 mol % equiv of PTC-1.
b
Isolated yields.

P.-S. Sun et al. / Tetrahedron 68 (2012) 1367e1370
1369
(200e300 mesh) is used for column chromatography, and the
distillation range of petroleum is 60e90 ꢀC. 1H and 13C NMR spectra
were recorded on the Varian Mercury-300 MHz or Varian Mercury-
400 MHz instruments, using CDCl3 as a solvent. IR spectra were
recorded on an FT-IR spectrometer and only major peaks are re-
ported in cmꢁ1. All new compounds were further characterized by
element analysis; copies of their 1H NMR and 13C NMR spectra are
provided. Commercially available reagents and solvents were used
without further purification.
1.14e1.09 (t, J¼7.2 Hz, 3H); 13C NMR (75 MHz, CDCl3)
d
204.4, 169.8,
169.7, 140.2, 135.9, 132.6, 131.7, 128.9, 128.8, 127.5, 124.8, 122.7,
121.3, 111.7, 101.1, 62.8, 62.2, 62.0, 39.7, 14.2, 13.9; IR (KBr, cmꢁ1
1735, 1247, 1176, 1054, 1006, 852, 757. Anal. Calcd for C23H21BrO4: C,
62.60; H, 4.80. Found: C, 62.68; H, 4.96.
)
4.2.6. Diethyl 1-(2-m-tolylvinylidene)-1H-indene-2,2(3H)-dicarbox-
ylate (2k). Oil: 1H NMR (300 MHz, CDCl3)
d 7.22e7.09 (m, 7H),
6.95e6.94 (m, 1H), 6.68 (s, 1H), 4.17e3.94 (m, 4H), 3.78e3.61 (q,
J¼17.1 Hz, 2H), 2.22 (s, 3H), 1.19e1.10 (m, 3H), 1.03e0.98 (m, 3H);
4.2. Typical procedure for the preparation of 2
13C NMR (75 MHz, CDCl3)
d 204.4, 169.9, 140.2, 138.3, 136.4, 133.4,
128.6, 128.4, 128.2, 127.5, 124.6, 124.6, 122.7, 111.2, 101.9, 62.7, 62.1,
61.9, 39.8, 21.3, 14.2, 13.9; IR (neat, cmꢁ1) 1732, 1250, 1184, 1056,
908, 734. Anal. Calcd for C24H24O4: C, 76.57; H, 6.43. Found: C,
76.46; H, 6.35.
To a solution of 1 (0.20 mmol) in 2.0 mL of DMF was added
Cs2CO3 (130.3 mg, 0.40 mmol) in the reaction vessel. The mixture
was allowed to stir at room temperature for 1 min and PTC
(3.15 mg, 5 mol %) was added. The vessel was sealed and the
resulting mixture was then heated at 60 ꢀC. When the reaction was
considered complete as determined by TLC analysis, the reaction
was allowed to cool to room temperature and quenched with
a saturated aqueous solution of ammonium chloride, and the
mixture was extracted with EtOAc. The combined organic extracts
were washed with water and saturated brine. The organic layers
were dried over Na2SO4, filtered. Solvents were evaporated under
reduced pressure. The residue was purified by chromatography on
silica gel to afford 2.
4.2.7. Diethyl 1-(2-(2-methoxyphenyl)vinylidene)-1H-indene-2,2(3H)-
dicarboxylate (2l). Oil: 1H NMR (400 MHz, CDCl3)
d 7.53e7.50 (m,
1H), 7.30e7.18 (m, 6H), 6.90e6.86 (m, 2H), 4.27e4.15 (m, 3H),
4.08e4.03 (m, 1H), 3.84e3.72 (m, 5H), 1.27e1.23 (m, 3H), 1.11e1.08
(m, 3H); 13C NMR (100 MHz, CDCl3)
d 204.5, 170.1, 156.3, 139.7, 136.6,
128.6, 128.5, 128.1, 127.5, 124.7, 122.6, 121.7, 120.6, 110.9, 110.6, 96.0,
62.8, 62.0, 61.8, 55.6, 39.8,14.2,13.9; IR (neat, cmꢁ1) 1730, 1250, 1176,
1055, 857, 758. Anal. Calcd for C24H24O5: C, 73.45; H, 6.16. Found: C,
73.39; H, 6.25.
4.2.1. Diethyl 1-vinylidene-1H-indene-2,2(3H)-dicarboxylate (2a). Oil:
4.2.8. Diethyl 1-(2-(furan-2-yl)vinylidene)-1H-indene-2,2(3H)-dicar
1H NMR (400 MHz, CDCl3)
d
7.26e7.18 (m, 4H), 5.38 (s, 2H), 4.27e4.19
boxylate (2m). Oil: 1H NMR (300 MHz, CDCl3)
d 7.36e7.20 (m, 5H),
(q, J¼6.9 Hz, 4H), 3.70 (s, 2H), 1.28e1.24 (t, J¼7.2 Hz, 6H); 13C NMR
6.77 (s, 1H), 6.40e6.35 (m, 2H), 4.28e4.08 (m, 4H), 3.91e3.63 (q,
J¼17.1 Hz, 2H), 1.28e1.23 (t, J¼7.2 Hz, 3H), 1.13e1.08 (t, J¼6.9 Hz,
(100 MHz, CDCl3) d 206.1,169.9,139.4,136.5,128.0,127.4,124.5,122.4,
82.5, 62.3, 61.9, 39.6, 14.0; IR (neat, cmꢁ1) 1736, 1245, 1178, 1057, 862,
765. Anal. Calcd for C17H18O4: C, 71.31; H, 6.34. Found: C, 71.48;
H, 6.62.
3H); 13C NMR (75 MHz, CDCl3)
d 203.8, 169.9, 169.7, 147.3, 142.4,
140.3, 136.2, 128.6, 127.5, 124.6, 123.0, 111.6, 108.6, 92.2, 62.8, 62.1,
61.9, 39.6, 14.1, 13.7; IR (neat, cmꢁ1) 1729, 1245, 1178, 1056, 1013,
759, 737. Anal. Calcd for C21H20O5: C, 71.58; H, 5.72. Found: C, 71.51;
H, 5.74.
4.2.2. Diethyl 1-(2-phenylvinylidene)-1H-indene-2,2(3H)-dicarbox-
ylate (2g). Oil: 1H NMR (300 MHz, CDCl3)
d 7.46e7.23 (m, 9H), 6.84
(s, 1H), 4.33e4.05 (m, 4H), 3.90e3.75 (q, J¼17.1 Hz, 2H), 1.32e1.27
4.2.9. Diethyl
1-(prop-1-enylidene)-1H-indene-2,2(3H)-dicarboxy
7.26e7.16 (m, 4H),
(t, J¼7.2 Hz, 3H), 1.13e1.09 (t, J¼7.2 Hz, 3H); 13C NMR (75 MHz,
late (2n). Oil: 1H NMR (300 MHz, CDCl3)
d
CDCl3)
d
204.2, 169.8, 169.8, 140.1, 136.3, 133.3, 128.6, 128.4, 127.5,
5.82e5.75 (q, J¼7.5 Hz, 1H), 4.28e4.16 (m, 4H), 3.77e3.63 (q,
127.4, 127.4, 124.7, 122.6, 111.3, 101.9, 62.8, 62.2, 61.9, 39.7, 14.1, 13.7;
IR (neat, cmꢁ1) 1734, 1247, 1183, 1057, 764, 694. Anal. Calcd for
C23H22O4: C, 76.22; H, 6.12. Found: C, 76.41; H, 6.26.
J¼17.1 Hz, 2H), 1.85e1.83 (d, J¼7.2 Hz, 3H), 1.31e1.23 (m, 6H); 13C
NMR (75 MHz, CDCl3) d 202.0, 170.1, 139.4, 137.2, 127.7, 127.2, 124.4,
122.2, 107.2, 93.5, 62.3, 61.7, 61.6, 39.5, 14.1, 14.0, 13.9; IR (neat,
cmꢁ1) 1736,1247, 1182, 1057, 756. Anal. Calcd for C18H20O4: C, 71.98;
H, 6.71. Found: C, 72.11; H, 6.75.
4.2.3. Diethyl 1-(2-p-tolylvinylidene)-1H-indene-2,2(3H)-dicarbox-
ylate (2h). Oil: 1H NMR (300 MHz, CDCl3)
d 7.30e7.18 (m, 6H),
7.11e7.09 (d, J¼7.5 Hz, 2H), 6.76 (s, 1H), 4.28e4.03 (m, 4H),
4.2.10. Diethyl 1-(2,2-diphenylvinylidene)-1H-indene-2,2(3H)-dicar
3.86e3.71 (q, J¼17.1 Hz, 2H), 2.32 (s, 3H), 1.26e1.20 (m, 3H),
boxylate (2o). Solid: mp 102e104 ꢀC; 1H NMR (300 MHz, CDCl3)
1.12e1.06 (m, 3H); 13C NMR (75 MHz, CDCl3)
d
203.8, 170.0, 170.0,
d 7.51e7.48 (m, 4H), 7.41e7.20 (m, 10H), 4.15e3.97 (m, 4H), 3.79 (s,
140.0,137.4,136.5,130.3,129.3,128.2,127.4,127.3,124.7,122.6,111.2,
101.6, 62.8, 62.1, 61.8, 39.6, 21.2, 14.1, 13.8; IR (neat, cmꢁ1) 1736,
1248, 1183, 1059, 852, 758. Anal. Calcd for C24H24O4: C, 76.57; H,
6.43. Found: C, 76.39; H, 6.36.
2H), 1.05e1.01 (t, J¼6.9 Hz, 6H); 13C NMR (75 MHz, CDCl3)
d 204.9,
170.0, 140.2, 136.6, 136.1, 128.6, 128.5, 128.4, 127.6, 127.5, 124.8,
122.5, 117.2, 110.4, 63.0, 61.9, 39.7, 13.5; IR (KBr, cmꢁ1) 1733, 1235,
1178, 1056, 765, 698. Anal. Calcd for C29H26O4: C, 79.43; H, 5.98.
Found: C, 79.38; H, 6.15.
4.2.4. Diethyl 1-(2-(4-chlorophenyl)vinylidene)-1H-indene-2,2(3H)-
dicarboxylate (2i). Oil: 1H NMR (300 MHz, CDCl3)
d
7.36e7.18 (m,
8H), 6.75 (s, 1H), 4.29e4.04 (m, 4H), 3.78 (s, 2H), 1.27e1.21 (m, 3H),
1.14e1.09 (m, 3H); 13C NMR (75 MHz, CDCl3)
204.5, 169.9, 169.8,
4.3. Typical procedure for the preparation of 4
d
To a solution of 3 (0.20 mmol) in 2.0 mL of DMF was added
Cs2CO3 (130.3 mg, 0.40 mmol) in the reaction vessel. The mixture
was allowed to stir at room temperature for 1 min and PTC
(3.15 mg, 5 mol %) was added. The vessel was sealed and the
resulting mixture was then heated at 60 ꢀC. When the reaction was
considered complete as determined by TLC analysis, the reaction
was allowed to cool to room temperature and quenched with
a saturated aqueous solution of ammonium chloride, and the
mixture was extracted with EtOAc. The combined organic extracts
were washed with water and saturated brine. The organic layers
140.2, 136.1, 133.1, 132.1, 128.8, 128.7, 128.6, 127.5, 124.8, 122.7, 111.7,
100.9, 62.8, 62.1, 62.0, 39.7, 14.2, 13.9; IR (neat, cmꢁ1) 1731, 1248,
1176, 1089, 1054, 853, 758. Anal. Calcd for C23H21ClO4: C, 69.61; H,
5.33. Found: C, 69.76; H, 5.27.
4.2.5. Diethyl 1-(2-(4-bromophenyl)vinylidene)-1H-indene-2,2(3H)-
dicarboxylate (2j). Solid: mp 99e100 ꢀC; 1H NMR (300 MHz, CDCl3)
d
7.45e7.43 (d, J¼8.4 Hz, 2H), 7.32e7.20 (m, 6H), 6.75 (s, 1H),
4.28e4.04 (m, 4H), 3.79 (m, 2H), 1.28e1.24 (t, J¼7.2 Hz, 3H),

1370
P.-S. Sun et al. / Tetrahedron 68 (2012) 1367e1370
were dried over Na2SO4, filtered. Solvents were evaporated under
reduced pressure. The residue was purified by chromatography on
silica gel to afford 4.
120.7, 118.6, 111.6, 34.8, 31.6, 27.9; IR (neat, cmꢁ1) 1649, 1536, 1271,
1053, 811, 697. Anal. Calcd for C16H18O2: C, 79.31; H, 7.49. Found: C,
79.24; H, 7.62.
4.3.1. Ethyl 3-(2-(2-oxo-2-phenylethoxy)phenyl)prop-2-ynyl car-
4.3.7. Ethyl 2-(4-chloro-2-(3-(ethoxycarbonyloxy)prop-1-ynyl)phe-
bonate (4a). Yellow solid: mp 58e60 ꢀC; 1H NMR (400 MHz, CDCl3)
noxy)acetate (4g). White solid: mp 66e68 ꢀC; 1H NMR (300 MHz,
d
8.11e8.09 (d, J¼7.6 Hz, 2H), 8.02e8.00 (d, J¼8.0 Hz, 1H), 7.64e7.49
CDCl3)
d
7.81 (s, 1H), 7.44e7.34 (m, 3H), 5.98e5.91 (dd, J¼1.2,
(m, 6H), 7.39e7.35 (t, J¼7.6 Hz, 1H), 6.18e6.13 (dd, J¼0.8, 18.0 Hz,
18.3 Hz, 1H), 5.63e5.59 (d, J¼10.5 Hz, 1H), 4.46e4.39 (dd, J¼1.2,
1H), 5.72e5.69 (dd, J¼1.2, 11.6 Hz, 1H); 13C NMR (100 MHz, CDCl3)
14.7 Hz, 2H), 1.43e1.39 (t, J¼7.2 Hz, 3H); 13C NMR (75 MHz, CDCl3)
d
185.6, 154.5, 147.9, 137.5, 132.6, 129.7, 128.2, 128.0, 127.9, 126.5,
d 159.6, 152.9, 142.0, 129.5, 127.9, 127.1, 126.8, 124.9, 122.0, 120.4,
125.9, 123.9, 122.8, 120.5, 112.3; IR (neat, cmꢁ1) 1649, 1530, 963,
729. Anal. Calcd for C17H12O2: C, 82.24; H, 4.87. Found: C, 82.35; H,
4.78.
113.4, 61.5, 14.3; IR (neat, cmꢁ1) 1713, 1554, 1273, 907, 802. Anal.
Calcd for C13H11ClO3: C, 62.29; H, 4.42. Found: C, 62.44; H, 4.27.
Acknowledgements
4.3.2. Ethyl 3-(5-methyl-2-(2-oxo-2-phenylethoxy)phenyl)prop-2-
ynyl carbonate (4b). Yellow oil: 1H NMR (400 MHz, CDCl3)
We are grateful for the National Science Foundation (NSF-
21072080) for financial support. We acknowledge National Basic
Research Program of China (973 Program), 2010CB833203.
d
8.05e8.03 (d, J¼8.0 Hz, 2H), 7.75 (s, 1H), 7.60e7.40 (m, 5H),
7.30e7.28 (d, J¼8.0 Hz, 1H), 6.14e6.09 (dd, J¼1.2, 18.0 Hz, 1H),
5.68e5.64 (dd, J¼1.2, 11.6 Hz, 1H), 2.48 (s, 3H); 13C NMR (75 MHz,
CDCl3)
d 185.7, 153.1, 148.1, 137.7, 133.6, 132.6, 129.8, 129.6, 128.2,
128.1, 126.4, 126.1, 122.4, 120.4, 111.9, 21.5; IR (neat, cmꢁ1) 1640,
1531, 1262, 1050, 802, 695. Anal. Calcd for C18H14O2: C, 82.42; H,
5.38. Found: C, 82.62; H, 5.26.
References and notes
1. (a) The Chemistry of the Allenes; Landor, S. R., Ed.; Academic: London, 1982; Vol.
l, p 1; (b) Modern Allene Chemistry; Krause, N., Hashmi, A. S. K., Eds.; Wiley-VCH:
Weinheim, 2004; Vols. 1 and 2; (c) Tsuji, J. Topics in Organometallic Chemistry;
Springer: Berlin, Heidelberg, 2005.
2. (a) Zimmer, R.; Dinesh, C. U.; Nandanan, E.; Khan, F. A. Chem. Rev. 2000, 100,
3067; (b) Bates, R. W.; Satcharoen, V. Chem. Soc. Rev. 2002, 31, 12; (c) Ma, S. Acc.
Chem. Res. 2003, 36, 701; (d) Hoffmann-Roder, A.; Krause, N. Angew. Chem., Int.
Ed. 2004, 43, 1196; (e) Reissig, H. U.; Schade, W.; Amombo, M. O.; Pulz, R.;
Hausherr, A. Pure Appl. Chem. 2002, 74, 175.
3. For some of the most recent typical reactions of allenes, see: (a) Ng, S.-S.;
Jamison, T. F. J. Am. Chem. Soc. 2005, 127, 7320; (b) Sieber, J. D.; Morken, J. P. J.
Am. Chem. Soc. 2006, 128, 74; (c) Lee, P. H.; Lee, K.; Kang, Y. J. Am. Chem. Soc.
2006, 128, 1139; (d) Lalonde, P. L.; Sherry, B. D.; Kang, E. J.; Toste, F. D. J. Am.
Chem. Soc. 2007, 129, 2452; (e) Chang, H.-T.; Jayanth, T. T.; Cheng, C. H. J. Am.
Chem. Soc. 2007, 129, 4166; (f) Banaag, A. R.; Tius, M. A. J. Am. Chem. Soc. 2007,
129, 5328.
4. Naso, F.; Ronzini, L. J. Chem. Soc., Perkin Trans. 1 1974, 340.
5. Bouis, M. Ann. Chim. Paris 1928, 9, 402.
6. Brandsma, L.; Arens, J. F. Recl. Trav. Chim. Pays-Bas 1967, 86, 734.
7. Bowes, C. M.; Montecalvo, D. F.; Sondheimer, F. Tetrahedron Lett. 1973, 34, 3181.
8. Schuster, H. F.; Coppola, G. M. Allenes in Organic Synthesis; John Wiley: New
York, NY, 1988.
9. Jones, W. M.; Grasley, M. H.; Brey, W. S. J. Am. Chem. Soc. 1963, 85, 2754.
10. Petrov, A. A.; Kormer, V. A.; Savich, I. G. Zh. Obshch. Khim. 1960, 30, 3845.
11. (a) Ruitenberg, K.; Kleijn, H.; Meijer, J.; Oostveen, E. A.; Vermeer, P. J. Organomet.
Chem. 1982, 224, 399; (b) de Graaf, W.; Boersma, J.; van Koten, G.; Elsevier, C. J. J.
Organomet. Chem. 1989, 378, 115; (c) Aidhen, I. S.; Braslau, R. Synth. Commun.
1994, 24, 789; (d) Badone, D.; Cardamone, R.; Guzzi, U. Tetrahedron Lett. 1994,
35, 5477; (e) Gillmann, T.; Weeber, T. Synlett 1994, 649.
4.3.3. 3-(5-tert-Butyl-2-(2-oxo-2-phenylethoxy)phenyl)prop-2-ynyl
ethyl carbonate (4c). White thick oil: 1H NMR (400 MHz, CDCl3)
d
8.06e8.04 (d, J¼8.0 Hz, 2H), 7.96 (s, 1H), 7.61e7.47 (m, 6H),
6.16e6.11 (dd, J¼0.8, 18.0 Hz, 1H), 5.71e5.68 (dd, J¼1.2, 11.6 Hz, 1H),
1.41 (s, 9H); 13C NMR (100 MHz, CDCl3)
185.8, 153.0, 148.3, 147.2,
d
137.8, 132.6, 129.8, 128.3, 128.2, 126.8, 126.5, 125.7, 120.5, 118.5,
111.8, 34.9, 31.7; IR (neat, cmꢁ1) 1673, 1540, 1361, 1114, 812. Anal.
Calcd for C21H20O2: C, 82.86; H, 6.62. Found: C, 82.73; H, 6.84.
4.3.4. 3-(5-Chloro-2-(2-oxo-2-phenylethoxy)phenyl)prop-2-ynyl
ethyl carbonate (4d). White solid: mp 93e95 ꢀC; 1H NMR
(400 MHz, CDCl3)
d
8.06e8.04 (d, J¼8.4 Hz, 2H), 7.92 (s, 1H),
7.63e7.41 (m, 6H), 6.06e6.01 (dd, J¼1.2, 18.4 Hz, 1H), 5.69e5.67 (d,
J¼8.0 Hz,1H); 13C NMR (100 MHz, CDCl3)
d 185.3, 152.7, 148.8, 137.2,
132.9, 129.7, 129.7, 128.3, 128.3, 127.4, 127.1, 125.7, 122.3, 120.8,
113.4; IR (neat, cmꢁ1) 1649, 1535, 1266, 968, 693. Anal. Calcd for
C17H11ClO2: C, 72.22; H, 3.92. Found: C, 72.34; H, 3.83.
4.3.5. Ethyl
3-(2-(2-oxopropoxy)phenyl)prop-2-ynyl
carbonate
(4e). Colorless oil: 1H NMR (400 MHz, CDCl3)
d
7.94e7.92 (d,
12. Ma, S. Chem. Rev. 2005, 105, 2829.
13. Bi, H.-P.; Liu, X.-Y.; Gou, F.-R.; Guo, L.-N.; Duan, X.-H.; Liang, Y.-M. Org. Lett.
2007, 9, 3527.
J¼8.0 Hz, 1H), 7.59e7.46 (m, 3H), 7.34e7.30 (m, 1H), 6.12e6.07 (dd,
J¼1.2, 18.0 Hz, 1H), 5.67e5.64 (dd, J¼1.2, 11.6 Hz, 1H), 2.62 (s, 3H);
13C NMR (100 MHz, CDCl3)
d 191.2, 154.3, 147.5, 128.1, 127.8, 126.2,
14. Gou, F.-R.; Bi, H.-P.; Guo, L.-N.; Guan, Z.-H.; Xue-Yuan Liu, X.-Y.; Liang, Y.-M. J.
Org. Chem. 2008, 73, 3837.
15. Hu, J.; Wang, X.-C.; Guo, L.-N.; Hu, Y.-Y.; Liu, X.-Y.; Liang, Y.-M. Catal. Commun.
2010, 11, 346.
16. (a) Dehmlow, E. V.; Dehmlow, S. S. Phase Transfer Catalysis, 3rd ed.; VCH:
Weinheim, Germany, 1993; (b) Starks, C. M.; Liotta, C. L.; Halpern, M. Phase-
Transfer Catalysis; Chapman & Hall: New York, NY, 1994; (c) Handbook of Phase-
Transfer Catalysis; Sasson, Y., Neumann, R., Eds.; Blackie Academic & Pro-
fessional: London, 1997; (d) Halpern, M.E., Ed.: Phase-Transfer Catalysis; ACS
Symposium Series 659; American Chemical Society: Washington, DC, 1997. (e)
Hashimoto, T.; Maruoka, K. Chem. Rev. 2007, 107, 5656.
124.1, 123.9, 123.0, 120.9, 112.3, 27.9; IR (neat, cmꢁ1) 1675, 1545,
1131, 746. Anal. Calcd for C12H10O2: C, 77.40; H, 5.41. Found: C,
77.31; H, 5.58.
4.3.6. 3-(5-tert-Butyl-2-(2-oxopropoxy)phenyl)prop-2-ynyl
ethyl
carbonate (4f). Yellow oil; 1H NMR (300 MHz, CDCl3)
d
7.81e7.80 (d,
J¼1.8 Hz, 1H), 7.51e7.33 (m, 3H), 6.04e5.97 (dd, J¼1.8, 18.3 Hz, 1H),
5.59e5.55 (dd, J¼1.8, 11.7 Hz, 1H), 2.51 (s, 3H), 1.29 (s, 9H); 13C NMR
17. Hu, J.; Wu, L.-Y.; Wang, X.-C.; Hu, Y.-Y.; Niu, Y.-N.; Liu, X.-Y.; Yang, S.-D.; Liang, Y.-
(75 MHz, CDCl3) d 191.1, 152.6, 147.8, 147.0, 127.9, 126.5, 125.8, 124.3,
M. Adv. Synth. Catal. 2010, 352, 351.