Polymer-supported tertiaryphosphine (JJ-TPP) as a green and recyclable organocatalyst for α-addition of carbon nucleophiles to α,β-unsaturated compounds

Article abstract of DOI:10.1016/j.tet.2007.12.038

JJ-TPP has been demonstrated as an effective and reusable organocatalyst for α-addition of carbon nucleophiles to α,β-unsaturated compounds under very mild and environmentally friendly conditions. Under the optimized reaction conditions, the desired addition products were obtained as only E isomer with 18-90% isolated yields.

Full text of DOI:10.1016/j.tet.2007.12.038

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Tetrahedron 64 (2008) 2120e2125
www.elsevier.com/locate/tet
Polymer-supported tertiaryphosphine (JJeTPP) as a green and
recyclable organocatalyst for a-addition of carbon
nucleophiles to a,b-unsaturated compounds
*
Hai-Ling Liu, Huan-Feng Jiang
The College of Chemistry, South China University of Technology, 381 Wushan Road, Guangzhou 510640, China
Received 21 September 2007; received in revised form 11 December 2007; accepted 14 December 2007
Available online 23 December 2007
Abstract
JJeTPP has been demonstrated as an effective and reusable organocatalyst for a-addition of carbon nucleophiles to a,b-unsaturated com-
pounds under very mild and environmentally friendly conditions. Under the optimized reaction conditions, the desired addition products were
obtained as only E isomer with 18e90% isolated yields.
Ó 2007 Elsevier Ltd. All rights reserved.
1. Introduction
tertiaryphosphines as perfect catalysts for other organic reac-
tions is still a challenge.
The development of metal-free organocatalysts and their
wide-ranging utilities for organic synthesis have received
much attention and remarkable achievements have been
made in this area recently.1 Among this family of organocata-
lysts, phosphines as efficient nucleophilic catalysts have been
widely used.2 One of the most successful applications is the
nucleophilic addition to the activated alkenes or alkynes,
such as Michael-type addition, a- and g-addition catalyzed
by tertiaryphosphines.3 However, in these previous addition
reactions the employed phosphines are homogeneous, which
makes the separation of products and recovery of catalysts
rather difficult sometimes. Moreover, volatile toxic solvents
such as toluene or benzene are required. To overcome these
limitations, phosphines are immobilized on the polymers,4,5
and these polymer-supported tertiaryphosphine reagents have
been successfully applied in the isomerization of a,b-ynones,6
Trost’s g-addition,7 Aza-BayliseHillman reaction,8 Moritae
BayliseHillman reaction.9 Despite significant advances in
this area, how to explore these polymer-supported
We have previously developed polymer-supported tertiary-
phosphines PSeTPP and JJeTPP as excellent catalysts for
the isomerization of a,b-ynones to (E,E)-a,b-g,d-dienones in
6a
toluene,
or under solvent-free condition.6b Encouraged by
these results, we further investigated the utilization of poly-
mer-supported tertiaryphosphines as catalysts for solvent-free
organic reactions, and herein we wish to show that polymer-
supported tertiaryphosphine JJeTPP (Fig. 1) is an excellent
organocatalyst for a-addition reaction of carbon nucleophiles
x+y/50
y
x
O
PPh2
O
1f JJ-TPP
x+y/50
* Corresponding author. Tel.: þ86 20 22236518; fax: þ86 20 87112906.
E-mail address: jianghf@scut.edu.cn (H.-F. Jiang).
Figure 1.
0040-4020/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2007.12.038

H.-L. Liu, H.-F. Jiang / Tetrahedron 64 (2008) 2120e2125
2121
to a,b-unsaturated compounds under very mild and environ-
mentally friendly conditions (solvent-free condition, room
temperature, and ambient atmosphere).
At the next step, we optimized reaction conditions by vary-
ing the amount of catalyst JJeTPP and reaction time. Reduc-
ing the amount of catalyst from 20 mol % to 10 mol % and
reaction time from 12 h to 6 h, the yields of 4aa was also
99%. Using 5 mol % of JJeTPP resulted in only 90% of
the desired product (Table 1, entry 11). The reaction time
could affect the reaction to some extent. The proper time is
beyond 6 h (Table 1, entries 9 and 10). The results in Table 1
revealed that the reaction was conducted smoothly with
10 mol % of JJeTPP at room temperature for 6 h under sol-
vent-free condition (Table 1, entry 9). It may be worth noting
that the product 4aa was isolated as only E isomer in stable
enolic form. Intramolecular hydrogen bond and conjugation
could stabilize the enolic form.10 When the reaction scale
was increased to 3 mmol, the reaction also proceeded
smoothly and the product was obtained in 96% yield based
on GC analysis.
Subsequently, we investigated the reusability of the cata-
lyst. JJeTPP could be recovered and reused through simple
filtration and vacuum drying. As shown in Table 2, the reused
catalyst gave the corresponding product 4aa in greater than
93% GC yield after multiple trials. As we all know, one draw-
back to the use of tertiaryphosphines is their inherent air-
sensitivity, which limits the reusability of catalysts. Whereas,
the a-addition reaction was carried out under ambient atmo-
sphere and the reused JJeTPP still retained its catalytic activ-
ity after the third use. We suspect that the bone of JandaJel
resin-supported triphenylphosphine is more air-stable. And
proper reaction temperature and reaction system might slow
down the oxidation of triphenylphosphine.
2. Results and discussion
The catalysts screening protocol employed the a-addition
reaction of 3a to 2a. Reactions were conducted with
0.25 mmol of 2a and 1.2 equiv of 3a using 20 mol % of differ-
ent catalysts at room temperature for 12 h under solvent-free
condition (unless otherwise mentioned). At first, we found
the reaction could not proceed without any catalyst. Triphenyl-
phosphine 1a, previously used as the homogeneous catalyst for
the Michael addition reaction, was found less effective. Then
with the polymer-supported tertiaryphosphines in hand, we ex-
amined the efficiency of 1bef as catalysts for the a-addition
reaction. As depicted in Table 1, using poly(ethylene glycol)-
supported triphenylphosphine 1b (PEGeTPP) and amphilic
resin 1c (PSePEGeDPP), no addition product was detected
(Table 1, entries 3 and 4). These results promoted us to test
less polar immobilized tertiaryphosphines. As expected, cata-
lyst polymer-supported diphenylphosphine 1d (PSeDPP) and
polymer-supported triphenylphosphine 1e (PSeTPP) could
give the desired product 4aa in 75 and 95% GC yields, respec-
tively (Table 1, entries 5 and 6). Loading level of the phospho-
rus has a close relationship with catalytic efficiency.8a P% of
1e is higher than that of 1d, which might be responsible for
the difference in product yields. Gratifyingly, the use of tri-
phenylphosphine supported on JandaJel resin 1f (JJeTPP)
resulted in 4aa with 99% yield. The reason why the catalytic
efficiency of homogeneous catalyst 1a is lower than that of
polymer-supported triphenylphosphine is not clear yet. Under
solvent-free conditions, polymer’s microenvironment might
promote the reagents assemble and phosphine group attacked
the substrates.
Under the given optimized reaction conditions, a variety of
ynones and 1,3-dicarbonyl compounds were applied for the a-
addition reaction using JJeTPP as catalyst at room tempera-
ture. The desired products were obtained as E isomer in enolic
form (except entries 10 and 11) with 18e90% isolated yields
as shown in Table 3. Representative ynones with different sub-
stituents on the R1 and R2 position could react with acetylace-
tone (3a) to generate the corresponding products with high
conversions and isolated yields (Table 3, entries 1e8). Subse-
quently, ethyl acetoacetate (3b) could undergo a-addition re-
action smoothly (entries 9 and 12e14). The use of diethyl
Table 1
Optimization of the a-addition reactiona
O
O
HO
O
O
Catalyst 1
+
r.t.
O
3a
4aa
2a
Table 2
Recycle of JJeTPPa
Entry Catalyst
Amount (%) Reaction time (h) Yieldb (%)
O
O
HO
1
None
TPP (1a)
PEGeTPP (1b)
d
20
20
12
12
12
12
12
12
12
12
6
0
44
0
2c
3
O
O
JJ-TPP
+
r.t. 12h
O
4
PSePEGeTPP (1c) 20
0
3a
2a
4aa
5
PSeDPP (1d)
PSeTPP (1e)
JJeTPP (1f)
JJeTPP
20
20
20
10
10
10
5
75
95
99
99
99
89
90
6
Conversionb (%)
Yieldb (%)
7
8
Fresh
99
99
98
97
99
99
93
93
9
JJeTPP
JJeTPP
JJeTPP
1
2
3
a
10
11
a
3
12
Reaction condition: 2a (0.25 mmol) and 3a (1.2 equiv) were added.
Determined by GC.
CH2Cl2 (2 mL) was added.
Reaction condition: 2a (0.25 mmol), 3a (1.2 equiv), and JJeTPP
b
(10 mol %) stand still for 12 h.
b
Determined by GC.
c

2122
H.-L. Liu, H.-F. Jiang / Tetrahedron 64 (2008) 2120e2125
Table 3
Addition of carbon nucleophiles to ynones catalyzed by JJeTPPa
Table 4
Addition of acetylacetone to other types of electron-deficient alkynes and
alkenes catalyzed by JJeTPPa
O
EWG1
EWG1
EWG2
O
Entry
1
Electrophile
Product
Yieldb (%)
JJ-TPP
R1
EWG2
+
R1
r.t., 6h
O
R2
R2
O
EtO2C
Yieldb (%)
63
Entry
2
3
4
OEt
5g
2a (R1¼Ph; R2¼Ph)
3a (EWG1¼EWG2¼ 4aa 88
HO
1
6ga
CH3CO)
2
2b (R1¼Ph; R2¼
3a
3a
3a
4ba 66
4ca 60
4da 80
O
4-CH3C6H4)
2c (R1¼4-O2NC6H4;
R2¼Ph)
EtO2C
CO2Et
OH
CO2Et
3
2
80
5h
EtO2C
4c
2d (R1¼4-CH3C6H4;
R2¼Ph)
6ha
5
6
2e (R1¼furan; R2¼Ph)
2f (R1¼thiophene;
R2¼Ph)
3a
3a
4ea 82
4fa 76
O
EtO2C
7c
8c
2g (R1¼R2¼4-CH3C6H4 3a
4ga 90
4ha 75
O
O
6ia
2h (R1¼thiophene;
R2¼4-CH3C6H4)
2a
3a
CO2Et
3c
62d
5i
3b (EWG1¼CH3CO; 4ab 78
EWG2¼COOEt)
EtO2C
6'ia
9
OH
10d
11d,e
2a
2a
3c (EWG1¼EWG2¼ 4ac 47
COOEt)
O
O
3d (EWG1¼EWG2¼ 4ad 18f
O
C6H5CO)
4
60
12c
13
14
a
2d
2e
2f
3b
3b
3b
4db 66
4eb 54
4fb 62
O
6ja
5j
O
Reaction condition: 2 (0.25 mmol), 3 (1.2 equiv), and JJeTPP (10 mol %)
for 6 h.
O
O
O
b
c
d
e
f
O
Isolated yield.
CH2Cl2 (0.5 g) was added.
18 h.
5e
75
O
O
5k
O
6ka
Tetrahydrofuran (0.2 g) was added.
Molar ratio of keto and enolic form was about 1:1.
CO2Et
5l
6
Complex
d
a
malonate (3c) as nucleophile led to the relatively low yield
(47%) of 4ac (entry 10). Dibenzoylmethane (3d) afforded
the product 4ad as a mixture of keto and enolic form in
only 18% isolated yield (entry 11).
Reaction condition: 5 (0.5 mmol), 3a (1.2 equiv), and JJeTPP (8 mol %)
stand still for 6 h.
b
Isolated yield.
12 h.
c
d
Molar ratio of 6ia/60ia¼1:1 and determined by 1H NMR.
e
These results prompted us to extend this process to other
types of electron-deficient alkynes and alkenes (Table 4). Using
ethyl 3-phenyl-2-propiolate (5g) and acetylacetone (3a) as reac-
tants, the desired a-addition product 6ga was obtained in 63%
isolated yield. Interestingly, 3a could undergo smoothly addi-
tiontodiethylacetylenedicarboxylate(5h)intheabsenceofcata-
lyst and solvent, and the reaction gave product 6ha with 80%
yield. The reaction of ethyl 2-butynoate (5i) with 3a gave
g-addition product 6ia in 62% isolated yield.11 There existed
the tautomerism of ketoeenol form and molar ratio of 6ia/
60ia¼1:1. The reaction conducted with acrylic compounds
afforded Michael adducts. If molar ratio of 3a/5j¼1.2:1, mono
Michael adduct 6ja was obtained in 60% yield and keto form
was themajorproduct. Double Michael adduct6kawas obtained
in 75% yield if molar ratio of 5k/3a¼2.5:1. However, a complex
mixture was obtained when using ethyl propiolate (5l).
Molar ratio of 5k/3a¼2.5:1.
The reaction of triphenylphosphine (1a) was carried out with
ethyl 3-phenyl-2-propiolate (5g) in aqueous THF (THF/
H2O¼5:1, v/v) for 12 h. 31P NMR chemical shift for Ph3P is
ꢀ3.76 in CDCl3. Whereas, a new species was obtained after
the reaction of 1a and 5g, which changed the chemical shift
of 31P to 26.36 suggesting the existence of phosphonium salt
7ag (Fig. 2). The formation of 7ag confirmed that the nucleo-
philic Michael addition of phosphine to ethyl 3-phenyl-2-
COO
O
OEt
THF/H2O
r.t. 12h
EtOH
+
+
Ph3P
Ph3P
In the course of this study, we conducted 31P NMR spec-
troscopy to obtain the evidence for the nucleophilic addition
of triphenylphosphine to a,b-unsaturated alkynes or alkenes.
5g
7ag
1a
Figure 2.

H.-L. Liu, H.-F. Jiang / Tetrahedron 64 (2008) 2120e2125
2123
propiolate generates zwitterions. Analogous zwitterions of
DABCO or PTA (1,3,5-triaza-7-phosphaadamantane) with
acrylic compounds were reported.12,13
4.2.2. 3-(1-Hydroxy-ethylidene)-2-(4-methyl-benzylidene)-
1-phenyl-pentane-1,4-dione (4ba)
1H NMR (CDCl3, 400 MHz) d: 1.94 (t, J¼8 Hz, 6H), 2.34
(s, 3H), 7.15 (d, J¼8 Hz, 2H), 7.31e7.57 (m, 6H), 7.77 (t,
J¼8 Hz, 2H), 16.75 (s, 1H); 13C NMR (CDCl3) d: 197.6,
191.0, 146.1, 140.8, 138.3, 133.9, 132.0, 131.8, 130.0,
129.8, 129.4, 128.5, 108.9, 23.5, 21.4; MS (70 eV) m/z (%):
320 (Mꢂþ), 302, 277, 259, 245, 235, 215, 185, 173, 143,
129, 105 (100), 91, 77, 43; IR (KBr) n: 3028, 2923, 1645,
1603, 1511, 1395, 1253, 1050, 990, 868 cmꢀ1. Anal. Calcd
for C21H20O3: C 78.73, H 6.29. Found: C 78.66, H 6.32.
3. Conclusion
In summary, JJeTPP as an effective organocatalyst for a-
addition of carbon nucleophiles to a,b-unsaturated compounds
has been demonstrated under the solvent-free condition at room
temperature under ambient atmosphere. JJeTPP is easy to be
recovered and reusable with high catalytic capability. More
remarkably, this protocol is compatible to various substrates.
4.2.3. 3-(1-Hydroxy-ethylidene)-2-(4-nitro-benzylidene)-1-
phenyl-pentane-1,4-dione (4ca)
4. Experimental
1H NMR (CDCl3, 400 MHz) d: 1.94 (s, 6H), 7.33e7.44 (m,
6H), 7.90 (t, J¼4 Hz, 2H), 8.35 (t, J¼4 Hz, 2H), 16.80 (s, 1H);
13C NMR (CDCl3) d: 195.9, 191.0, 149.7, 147.5, 143.9, 134.7,
134.0, 131.0, 130.2, 130.1, 129.3, 123.8, 108.0, 23.5; MS
(70 eV) m/z (%): 351, 333, 308, 290, 266, 231, 215, 201,
183, 159, 150, 134, 104, 92, 76, 63, 43; IR (KBr) n: 3064,
2985, 1743, 1653, 1457, 1371, 1102, 1035 cmꢀ1. Anal. Calcd
for C20H17NO5: C 68.37, H 4.88, N 3.99. Found: C 68.66, H
4.82, N 4.10.
4.1. General
Ynones were prepared according to the reference.14 PEGe
TPP (mp¼44e46 ꢁC, 0.4 mmol P/g) and PSeDPP (200e400
mesh, 2%DVB, 2.5 mmol P/g) were purchased from Fluka.
PSeTPP (200e400 mesh, 2%DVB, 3.0 mmol P/g) and JJe
TPP (70e90 mesh, 2%DVB, 2e3 mmol P/g) were purchased
from Aldrich chemical company. PSePEGeTPP (0.6 mmol
P/g) was prepared according to the patent.15 All reactions
were performed in a pear bottom flask without N2 protection.
Reagents were purchased from commercial suppliers and used
without further purification. NMR spectra (1H, 13C, and 31P)
were recorded with Bruker Avance 400 MHz spectrometer
using TMS as the internal standard (1H and 13C) and 85%
phosphoric acid as external standard (31P). IR spectra were
obtained as potassium bromide pellets or as liquid films with
a Brucker Vector 22 spectrometer. GC and Mass Spectra
were run on a Finnigan Trace DSQ spectrometer. TLC (thin
layer chromatography) was performed by using commercially
available 100e400 mesh silica gel plates (GF 254), and visu-
alization was effected at 254 nm. Elemental analysis was per-
formed on a Vario EL elemental analyzer.
4.2.4. 2-Benzylidene-3-(1-hydroxy-ethylidene)-1-p-tolyl-
pentane-1,4-dione (4da)
1H NMR (CDCl3, 400 MHz) d: 1.94 (s, 6H), 2.44 (s, 3H),
7.28e7.43 (m, 8H), 7.73 (d, J¼8 Hz, 2H), 16.76 (s, 1H);
13C NMR (CDCl3) d: 197.2, 191.0, 145.0, 143.1, 135.2,
134.9, 134.7, 130.0, 129.9, 129.8, 129.2, 129.0, 109.1, 23.5,
21.6; MS (70 eV) m/z (%): 320 (Mꢂþ), 302, 277, 259, 245,
235, 217, 201, 185, 159, 143, 119 (100), 105, 91, 65, 43; IR
(KBr) n: 3030, 2924, 1645, 1606, 1494, 1401, 1254, 1043,
920, 867 cmꢀ1. Anal. Calcd for C21H20O3S: C 78.73, H
6.29. Found: C 78.59, H 6.52.
4.2.5. 2-Benzylidene-1-furan-2-yl-3-(1-hydroxy-ethylidene)-
pentane-1,4-dione (4ea)
1H NMR (CDCl3, 400 MHz) d: 1.92 (s, 6H), 6.56 (t, J¼4 Hz,
1H), 7.18 (d, J¼4 Hz, 1H), 7.35e7.70 (m, 7H), 16.74 (s, 1H);
13C NMR (CDCl3) d: 191.4, 183.0, 152.2, 147.0, 143.1, 134.8,
133.9, 130.1, 129.1, 119.5, 112.2, 108.9, 23.6; MS (70 eV)
m/z (%): 296 (Mꢂþ, 100), 267, 253, 235, 228, 185, 158, 151,
115, 95 (100), 77, 43; IR (KBr) n: 3059, 2925, 1637, 1461,
1392, 1273, 1018, 925, 888 cmꢀ1. Anal. Calcd for C18H16O4:
C 72.96, H 5.44. Found: C 72.85, H 5.60.
4.2. Typical procedure for the preparation of 4
To a pear-shaped flask JJeTPP (10 mol %), ynones 2
(0.25 mmol), and 3 (1.2 equiv) were added and stood still at
room temperature for 6 h. Then 5 mL ethyl ether was added
and stirred for 1 h. After the catalyst was separated by filtra-
tion, the residue was isolated by preparative TLC to obtain
pure products 4. The reused catalyst was washed several times
with ethyl ether and stored under vacuum for next use.
4.2.6. 2-Benzylidene-3-(1-hydroxy-ethylidene)-1-thiophen-
2-yl-pentane-1,4-dione (4fa)
1H NMR (CDCl3, 400 MHz) d: 1.93 (s, 6H), 7.15 (t, J¼4 Hz,
1H), 7.35e7.80 (m, 8H), 16.81 (s, 1H); 13C NMR (CDCl3) d:
191.5, 187.6, 143.1, 142.6, 134.8, 134.4, 134.3, 134.0, 130.1,
130.0, 129.1, 128.0, 23.7; MS (70 eV) m/z (%): 312 (Mꢂþ),
294, 269, 251, 228, 201, 185, 171, 158, 151, 115, 111 (100),
105, 83, 63, 43; IR (KBr) n: 3092, 2924, 1627, 1508, 1411,
1204, 1001, 920, 855 cmꢀ1. Anal. Calcd for C18H16O3S: C
69.21, H 5.16. Found: C 69.10, H 5.30.
4.2.1. 2-Benzylidene-3-(1-hydroxy-ethylidene)-1-phenyl-
pentane-1,4-dione (4aa)3i
1H NMR (CDCl3, 400 MHz) d: 1.94 (s, 6H), 7.34e7.59 (m,
9H), 7.80 (t, J¼4 Hz, 2H), 16.77 (s, 1H); MS (70 eV) m/z (%):
306 (Mꢂþ), 263, 245, 221, 201, 159, 115, 105 (100), 77, 43; IR
(KBr) n: 3058, 1645, 1605, 1493, 1399, 1253, 1016, 932,
863 cmꢀ1
.

2124
H.-L. Liu, H.-F. Jiang / Tetrahedron 64 (2008) 2120e2125
4.2.7. 3-(1-Hydroxy-ethylidene)-2-(4-methyl-benzylidene)-
1-p-tolyl-pentane-1,4-dione (4ga)
4.2.12. 3-Hydroxy-2-[1-(4-methyl-benzoyl)-2-phenyl-vinyl]-
but-2-enoic acid ethyl ester (4db)
1H NMR (CDCl3, 400 MHz) d: 1.93 (d, J¼4 Hz, 6H), 2.34 (s,
3H), 2.43 (s, 3H), 7.15 (d, J¼8 Hz, 2H), 7.27e7.33 (m, 5H), 7.71
(d, J¼8 Hz, 2H), 16.74 (s, 1H); 13C NMR (CDCl3) d: 197.3,
191.0, 145.3, 142.9, 140.7, 135.4, 134.0, 131.9, 130.0,
129.8, 129.7, 129.2, 109.1, 23.5, 21.6, 21.4; MS (70 eV) m/z
(%): 334 (Mꢂþ), 316, 301, 273, 249, 215, 200, 173, 157, 129,
119 (100), 115, 91, 65, 43; IR (KBr) n: 3029, 2923, 1643,
1605, 1510, 1398, 1255, 1021, 921, 872 cmꢀ1. Anal. Calcd for
C22H22O3: C 79.02, H 6.63. Found: C 78.78, H 6.84.
1H NMR (CDCl3, 400 MHz) d: 1.04 (t, J¼8 Hz, 3H), 1.71
(s, 3H), 2.41 (s, 3H), 4.10 (d, J¼8 Hz, 2H), 7.08 (s, 1H), 7.25e
7.7.39 (m, 7H), 7.75 (d, J¼8 Hz, 2H), 12.96 (s, 1H); 13C NMR
(CDCl3) d: 197.9, 175.0, 171.9, 142.7, 142.0, 135.6, 135.4,
134.4, 130.0, 129.3, 129.2, 128.9, 128.7, 99.0. 60.8, 21.6,
19.5, 13.9; MS (70 eV) m/z (%): 304 (Mꢀ46), 289 (100),
261, 213, 199, 189, 171, 128, 119, 91, 65, 43; IR (KBr) n:
2982, 1651, 1608, 1380, 1247, 1069, 963, 867 cmꢀ1. Anal.
Calcd for C22H22O4: C 75.41, H 6.33. Found: C 75.15, H 6.55.
4.2.8. 3-(1-Hydroxy-ethylidene)-2-(4-methyl-benzylidene)-
1-thiophen-2-yl-pentane-1,4-dione (4ha)
4.2.13. 2-[1-(Furan-2-carbonyl)-2-phenyl-vinyl]-but-2-
enoic acid ethyl ester (4eb)
1H NMR (CDCl3, 400 MHz) d: 1.93 (s, 6H), 2.35 (s, 3H),
7.13e7.18 (m, 3H), 7.36 (d, J¼8 Hz, 2H), 7.66e7.79 (m,
3H), 16.81 (s, 1H); 13C NMR (CDCl3) d: 191.6, 187.5,
143.3, 142.7, 140.7, 134.1, 133.9, 133.3, 132.0, 130.1,
129.8, 127.9, 109.4, 23.6, 21.4; MS (70 eV) m/z (%): 326
(Mꢂþ), 308, 283, 265, 251, 242, 227, 199, 185, 172, 128,
111 (100), 91, 83, 57, 43; IR (KBr) n: 3025, 2923, 1628,
1510, 1411, 1257, 1053, 922, 861 cmꢀ1. Anal. Calcd for
C19H18O3S: C 69.91, H 5.56. Found: C 69.78, H 5.86.
1H NMR (CDCl3, 400 MHz) d: 0.97 (t, J¼4 Hz, 3H), 1.72
(s, 3H), 4.04e4.10 (m, 2H), 6.51 (t, J¼4 Hz, 1H), 7.12 (d,
J¼4 Hz, 1H), 7.30e7.63 (m, 7H), 13.03 (s, 1H); 13C NMR
(CDCl3) d: 183.5, 175.0, 171.9, 152.3, 146.7, 141.0, 135.5,
133.1, 129.5, 129.3, 128.7, 119.2, 111.9, 98.9, 60.8, 19.5,
13.8; MS (70 eV) m/z (%): 280 (Mꢀ46, 100), 265, 252, 234,
209, 199, 181, 152, 128, 95, 89, 43; IR (KBr) n: 3132, 2984,
1646, 1567, 1463, 1389, 1245, 1059, 934, 856 cmꢀ1. Anal.
Calcd for C19H18O5: C 69.93, H 5.56. Found: C 69.75, H 5.25.
4.2.9. 2-(1-Benzoyl-2-phenyl-vinyl)-3-hydroxy-but-2-enoic
acid ethyl ester (4ab)
4.2.14. 3-Hydroxy-2-[2-phenyl-1-(thiophene-2-carbonyl)-
vinyl]-but-2-enoic acid ethyl ester (4fb)
1H NMR (CDCl3, 400 MHz) d: 1.05 (t, J¼8 Hz, 3H), 1.71
(s, 3H), 4.11 (q, J¼8 Hz, 2H), 7.10 (s, 1H), 7.31e7.54 (m,
8H), 7.83 (t, J¼4 Hz, 2H), 12.98 (s, 1H); 13C NMR (CDCl3)
d: 198.2, 174.9, 171.9, 142.7, 138.4, 135.3, 134.3, 132.0,
129.7, 129.4, 129.3, 128.7, 128.2, 98.8, 60.8, 19.4, 19.3; MS
(70 eV) m/z (%): 290 (Mꢀ46), 275 (100), 261, 247, 218,
213, 199, 189, 171, 143, 127, 105, 77, 51; IR (KBr) n: 3062,
2978, 1650, 1446, 1247, 1067, 959, 861 cmꢀ1. Anal. Calcd
for C21H20O4: C 74.98, H 5.99. Found: C 74.88, H 5.90.
1H NMR (CDCl3, 400 MHz) d: 0.96 (t, J¼8 Hz, 3H), 1.73
(s, 3H), 4.07 (q, J¼8 Hz, 2H), 7.11 (t, J¼4 Hz, 1H), 7.32e7.77
(m, 8H), 13.05 (s, 1H); 13C NMR (CDCl3) d: 188.5, 175.4,
171.9, 143.2, 140.7, 135.5, 133.8, 133.5, 129.4, 129.2,
128.7, 127.7, 99.2, 60.9, 19.6, 13.7; MS (70 eV) m/z (%):
341 (Mꢀ1), 312, 296 (Mꢀ46), 281, 263, 250, 221, 212,
199, 171, 155, 128, 111, 83, 39; IR (KBr) n: 3093, 2925,
1639, 1508, 1410, 1249, 1062, 962, 855 cmꢀ1. Anal. Calcd
for C19H18O4S: C 66.65, H 5.30. Found: C 66.50, H 5.17.
4.2.10. 2-(1-Benzoyl-2-phenyl-vinyl)-malonic acid diethyl
ester (4ac)
4.3. Typical procedure for the preparation of 6
1H NMR (CDCl3, 400 MHz) d: 1.21e1.26 (m, 6H), 4.15e
4.26 (m, 4H), 4.86 (s, 1H), 7.37e7.55 (m, 9H), 7.82e7.84 (m,
2H); 13C NMR (CDCl3) d: 196.7, 167.7, 144.1, 137.5, 134.4,
134.3, 132.2, 129.9, 129.8, 129.2, 128.8, 128.3, 127.9, 62.0,
61.9, 51.5, 13.9; MS (70 eV) m/z (%): 366 (Mꢂþ), 348, 321,
293, 275, 264, 247, 207, 191, 160, 143, 115, 105 (100), 77,
51, 29; IR (KBr) n: 3061, 2984, 1735, 1657, 1591, 1451,
1246, 1035, 979, 869 cmꢀ1. Anal. Calcd for C22H22O5: C
72.12, H 6.05. Found: C 72.30, H 6.32.
To a pear-shaped flask JJeTPP (8 mol %), 5 (0.5 mmol),
and 3a (1.2 equiv) were added and stood still at room temper-
ature for 6 h. Then 5 mL ethyl ether was added and stirred for
1 h. After the catalyst was separated by filtration, the residue
was isolated by preparative TLC to obtain pure products 6.
4.3.1. 3-Acetyl-2-benzylidene-4-hydroxy-pent-3-enoic acid
ethyl ester (6ga)3i
1H NMR (CDCl3, 400 MHz) d: 1.31 (t, J¼8 Hz, 3H), 1.90 (s,
6H), 4.27 (q, J¼8 Hz, 2H), 7.33e7.35 (m, 3H), 7.43e7.45 (m,
2H), 7.85 (s, 1H), 16.65 (s, 1H); MS (70 eV) m/z (%): 274
(Mꢂþ), 256, 228, 213, 185, 158, 129, 115, 105, 77, 43; IR (KBr)
4.2.11. 2-Benzylidene-3-(hydroxyl-phenyl-methlene)-1,4-
diphenyl-1,4-dione (4ad)
1H NMR (CDCl3, 400 MHz) d: 7.15e7.91 (m, 43H), 17.48
(s, 1H); 13C NMR (CDCl3) d: 196.4, 195.6, 195.0, 194.8,
180.8, 154.4, 150.8, 145.2, 142.5, 139.8, 136.9, 133.0,
130.3, 129.9, 128.5, 128.2, 128.1, 128.0, 127.8, 127.6,
124.3, 60.6; MS (70 eV) m/z (%): 430 (Mꢂþ), 325, 297, 247,
223, 191, 165, 147, 129, 115, 105, 77, 69, 51, 32; IR (KBr)
n: 3061, 2983, 1709, 1622, 1395, 1242, 1120, 1100, 1030 cmꢀ1
.
4.3.2. 2-(1-Acetyl-2-hydroxy-propenyl)-but-enedioic acid
diethyl ester (6ha)
1H NMR (CDCl3, 400 MHz) d: 1.23 (t, J¼8 Hz, 3H), 1.30
(t, J¼8 Hz, 3H), 1.94 (s, 6H), 4.17 (q, J¼8 Hz, 2H), 4.27 (q,
J¼8 Hz, 2H), 7.05 (s, 1H), 16.50 (s, 1H); MS (70 eV) m/z
n: 2960, 1646, 1490, 1447, 1386, 1317, 1260, 1025 cmꢀ1
.

H.-L. Liu, H.-F. Jiang / Tetrahedron 64 (2008) 2120e2125
2125
(%): 270 (Mꢂþ), 255, 227, 209, 197, 181, 151 (100), 126, 109,
93, 82, 53, 43; 13C NMR (CDCl3) d: 189.9, 166.2, 164.8,
139.5, 132.4, 107.2, 62.2, 61.2, 23.5, 14.1, 14.0; IR (KBr) n:
2985, 2938, 1720, 1638, 1394, 1240, 1030 cmꢀ1. Anal. Calcd
for C13H18O6: C 57.77, H 6.71. Found: C 57.92, H 6.50.
and Guangdong Natural Science Foundation (No. 07118070)
for financial support of this work.
References and notes
1. Reviews on reactions catalyzed by purely small organic molecules: (a)
Lu, X.; Zhang, C.; Xu, Z. Acc. Chem. Res. 2001, 34, 535; (b) Groger,
H. Chem. Rev. 2003, 103, 2795; (c) France, S.; Guerin, D. J.; Miller,
S. J.; Lectka, T. Chem. Rev. 2003, 103, 2985; (d) Huang, Y.; Unni,
A. K.; Thadani, A. N.; Rawal, V. H. Nature 2003, 424, 146; (e)
Ooi, T.; Maruoka, K. Acc. Chem. Res. 2004, 37, 526; (f) Shi, Y.
Acc. Chem. Res. 2004, 37, 488; (g) Allemann, C.; Gordillo, R.; Clem-
ente, F. R.; Cheong, P. H.-Y.; Houk, K. N. Acc. Chem. Res. 2004, 37,
558.
4.3.3. 5-Acetyl-6-hydroxy-hepta-2,5-dienoic acid
ethyl ester (6ia)7
1H NMR (CDCl3, 400 MHz) (molar ratio of 6ia/60ia¼1:1) d:
1.26 (q, J¼8 Hz, 3H), 2.07 (s, 3H), 2.18 (s, 3H), 2.68e2.72 (m,
1H), 3.13 (dt, J1¼8 Hz, J2¼4 Hz, 1H), 3.76 (m, 0.5H, CH),
4.12e4.19 (m, 2H), 3.13 (dt, J1¼16 Hz, J2¼8 Hz, 1H), 6.75e
6.98 (m, 1H), 16.74 (s, 0.5H, OH); MS (70 eV) m/z (%): 212
(Mꢂþ), 194, 170, 141, 125 (100), 99, 81, 53, 43; IR (KBr) n:
2. Methot, J. L.; Roush, W. R. Adv. Synth. Catal. 2004, 346, 1035.
2985, 2933, 1714, 1652, 1423, 1365, 1272, 1215, 1095 cmꢀ1
.
~
3. (a) Gimbert, C.; Lumbierres, M.; Marchi, C.; Moreno-Manas, M.;
Sebastian, R. M.; Vallribera, A. Tetrahedron 2005, 61, 8598; (b)
´
~
´
Gimbert, C.; Moreno-Manas, M.; Perez, E.; Vallribera, A. Tetrahedron
2007, 63, 8305; (c) Issa, Y.; Norollah, H.; Malek, T. M.; Sanaz, S.
J. Mol. Catal. A: Chem. 2007, 264, 313; (d) Lecercle, D.; Sawicki, M.;
Taran, F. Org. Lett. 2006, 8, 4283; (e) Dudding, T.; Kwon, O.; Mercier,
E. Org. Lett. 2006, 8, 3643; (f) Ana Liza, L.; Michael, J. K. Synthesis
2004, 15, 2579; (g) Virieux, D.; Guillouzic, A.-F.; Cristau, H.-J. Tetra-
hedron 2006, 62, 3710; (h) Xu, L.-W.; Xia, C.-G. Tetrahedron Lett.
4.3.4. 3-Acetyl-heptane-2,6-dione (6ja)16
1H NMR (CDCl3, 400 MHz) d: 2.01e2.18 (m, 11H), 2.41
(t, J¼8 Hz, 2H), 3.61 (t, J¼8 Hz, 1H); MS (70 eV) m/z (%):
170 (Mꢂþ), 152, 128 (100), 110, 95, 85, 71, 58, 43; IR
(KBr) n: 1709, 1618, 1421, 1361 cmꢀ1
.
´
2004, 45, 4507; (i) Hanedanian, M.; Loreau, O.; Sawicki, M.; Taran, F.
4.3.5. 4,4-Diacetyl-heptanedioic acid dimethyl ester (6ka)16
1H NMR (CDCl3, 400 MHz) d: 2.08e2.21 (m, 14H), 3.67
(s, 6H); MS (70 eV) m/z (%): 273 (Mþ1), 254, 230, 212,
198, 170, 167, 157, 138, 125, 110, 97, 81, 55, 43; IR (KBr)
´
Tetrahedron 2005, 61, 2287; (j) Hanedanian, M.; Loreau, O.; Taran, F.;
Mioskowski, C. Tetrahedron Lett. 2004, 45, 7035; (k) Liu, H.-L.; Jiang,
H.-F.; Wang, Y.-G. Chin. J. Chem. 2007, 25, 1023.
4. (a) Farrall, M. J.; Frechet, J. M. J. J. Org. Chem. 1976, 41, 3877; (b)
Thomas, G. L.; Boehner, C.; Ladlow, M.; Spring, D. R. Tetrahedron
2005, 61, 12153; (c) Choi, M. K. W.; He, H. S.; Toy, P. H. J. Org.
Chem. 2003, 68, 9831.
n: 2961, 2875, 1734, 1459, 1362, 1184, 1073 cmꢀ1
.
´
5. Guino, M.; (Mimi) Hii, K. K. Chem. Soc. Rev. 2007, 36, 608.
4.4. Typical procedure for the preparation of 7ag
6. (a) Wang, Y.-G.; Jiang, H.-F.; Liu, H.-L.; Liu, P. Tetrahedron Lett. 2005,
46, 3935; (b) Liu, H.-L.; Jiang, H.-F.; Xu, L.; Zhan, H.-Y. Tetrahedron
Lett. 2007, 48, 8371.
To a 25 mL round bottom flask, TPP 1a (0.5 mmol), ethyl 3-
phenyl-2-propiolate 5g (0.6 mmol) and 3 mL of aqueous THF
(THF:H2O¼5:1, v/v) were added and stirred for 12 h at room
temperature. Then the solvent was evaporated under reduced
pressure. To the residuewas added 10 mL Et2O and a lot of white
solid was produced. After filtration 7ag was obtained.
7. Skouta, R.; Varma, R. S.; Li, C.-J. Green. Chem. 2005, 7, 571.
8. (a) Zhao, L.-J.; He, H.-S.; Shi, M.; Toy, P. H. J. Comb. Chem. 2004, 6,
680; (b) Huang, J.-W.; Shi, M. Adv. Synth. Catal. 2003, 345, 953; (c)
Zhao, L. J.; Kwong, C. K. W.; Shi, M.; Toy, P. H. Tetrahedron 2005,
61, 12026.
9. Kwong, C. K.-W.; Huang, R.; Zhang, M.; Shi, M.; Toy, P. H. Chem.dEur.
J. 2007, 13, 2369.
4.4.1. Phosphonium salt 7ag
10. (a) Dannenberg, J. J.; Rios, R. J. Phys. Chem. 1994, 98, 6714; (b) Sanz, P.;
1H NMR (CDCl3, 400 MHz) d: 6.90e7.74 (m, 21H); 31P
NMR (D2O) d: 26.36; 13C NMR (D2O) d: 173.8, 173.6, 153.4,
137.9, 137.5, 137.4, 136.6, 136.5, 134.5, 134.4, 134.3, 132.6,
132.5, 132.2, 132.1, 131.7, 131.6, 131.4, 131.0, 127.1, 126.4,
119.7, 118.8; IR (KBr) n: 3058, 3024, 1642, 1611, 1484, 1439,
Mo, O.; Yanez, M.; Elguero, J. J. Phys. Chem. A 2007, 111, 3585; (c)
Urbanczyk-Lipkowska, Z.; Yoshizawa, K.; Toyota, S.; Toda, F. CrystEng-
Comm 2003, 5, 114.
´
´~
11. (a) Trost, B. M.; Li, C.-J. J. Am. Chem. Soc. 1994, 116, 3167; (b) Trost,
B. M.; Li, C.-J. J. Am. Chem. Soc. 1994, 116, 10819; (c) Trost, B. M.;
Dake, G. R. J. Am. Chem. Soc. 1997, 119, 7595.
1368, 1316, 1164, 1104 cmꢀ1
.
12. He, Z.; Tang, X.; Chen, Y.; He, Z. Adv. Synth. Catal. 2006, 348, 413.
13. Yu, C.; Liu, B.; Hu, L. J. Org. Chem. 2001, 66, 5413.
14. Cox, R. J.; Ritson, D. J.; Dane, T. A.; Berge, J.; Charmant, J. P. H.;
Kantacha, A. Chem. Commun. 2005, 1037.
Acknowledgements
15. Jiang, H.; Zhan, H.; Zou, B.; Zhou, L.; Yang, S.; Liu, H.; Qi, C.; Shen, Y.
CN. 200710026362.8, 2007.
The authors thank the National Natural Science Foundation
of China (Nos. 20772034, 20625205, 20572027, and 20332030)
16. Ranu, B. C.; Banerjee, S.; Jana, R. Tetrahedron 2007, 63, 776.