Palladium(II) and palladium(0)-cocatalyzed ring opening and oxidation reactions of 2-(arylmethylene)cyclopropylcarbinols

Article abstract of DOI:10.1016/j.tet.2009.02.028

In the presence of Pd(II) acetate and triethylamine as well as triphenylphosphine, 2-(arylmethylene)cyclopropylcarbinols 1 underwent ring opening and oxidation reactions smoothly to deliver (2E,4E)-5-arylpenta-2,4-dienals 2 in toluene at 60 °C in moderate

Full text of DOI:10.1016/j.tet.2009.02.028

Tetrahedron 65 (2009) 3404–3408
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Tetrahedron
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Palladium(II) and palladium(0)-cocatalyzed ring opening and oxidation reactions
of 2-(arylmethylene)cyclopropylcarbinols
*
Min Shi , Guo-Qiang Tian, Jia Li
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Road, Shanghai 200032, China
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 5 January 2009
Received in revised form 17 February 2009
Accepted 17 February 2009
Available online 21 February 2009
In the presence of Pd(II) acetate and triethylamine as well as triphenylphosphine, 2-(aryl-
methylene)cyclopropylcarbinols 1 underwent ring opening and oxidation reactions smoothly to deliver
(2E,4E)-5-arylpenta-2,4-dienals 2 in toluene at 60 ꢀC in moderate to good yields under ambient atmo-
sphere. Mechanisms involved with an in situ generated Pd(0) species from Pd(II) and Et3N or PPh3
catalyzed isomerization of 1 to provide (E,E)-5-arylpenta-2,4-dien-1-ols 3 and following a Pd(II) cata-
lyzed aerobic oxidation of 3 have been proposed on the basis of control and deuterium labeling
experiments.
Keywords:
Palladium(II) and palladium(0)
2-(Arylmethylene)cyclopropylcarbinols
(2E,4E)-5-Arylpenta-2,4-dienals
Ring opening and oxidation reactions
Triethylamine
Ó 2009 Elsevier Ltd. All rights reserved.
Triphenylphosphine
1. Introduction
and (2E,4E)-5-phenylpenta-2,4-dienal 2a was obtained in 43% yield
within 5.0 h under argon atmosphere (Table 1, entry 1). In the
Methylenecyclopropanes (MCPs) are highly strained and readily
accessible compounds that can serve as useful building blocks for
a variety of transformations in the presence of metal catalysts,
Lewis acids or Brønsted acids under mild conditions.1 2-(Arylme-
thylene)cyclopropylcarbinols 1 are a new kind of MCPs bearing an
additional hydroxymethyl group,2 and as demonstrated by our
group, can undergo a variety of transformations triggered by the
nucleophilic hydroxyl group under milder conditions.3 In view of
this point, we hypothesized that the tethered hydroxyl group in 1
might undergo an oxidation reaction along with a ring-opening
process in the presence of a transitional metal catalyst. Herein, we
wish to report the palladium(II) and palladium(0)-cocatalyzed ring
opening and oxidation reactions of 2-(arylmethylene)cyclopropyl-
carbinols 1 in the presence of triphenylphosphine and triethyl-
amine to furnish (2E,4E)-5-arylpenta-2,4-dienals 2 in moderate to
good yields under ambient atmosphere.
absence of Et3N or using PdCl2 as the catalyst, none of 2a was
formed under identical conditions (Table 1, entries 2 and 3). Using
PPh3 (0.18 mmol) as the ligand afforded 2a in 42% yield within
5.0 h even in the absence of Et3N under argon atmosphere (Table 1,
entry 4). Pd(PPh3)4 [palladium(0)] did not promote this reaction
and the coexistence of PPh3 and Et3N with Pd(OAc)2 did not im-
prove the yield of 2a under the standard conditions (Table 1, en-
tries 5 and 6). It should be noted that under oxygen atmosphere, no
reaction occurred whether using Pd(OAc)2/PPh3 as the catalyst or
even in the presence of Et3N (Table 1, entries 7 and 8). Using
Pd(OAc)2/PPh3 as the catalyst and CuCl2 as the additive under ox-
ygen atmosphere, no reaction occurred either (Table 1, entry 9).
Other additives such as 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU),
Cs2CO3, and N,N,N0,N’-tetramethylethylenediamine (TMEDA) did
not produce 2a under the standard conditions (Table 1, entries 10–
14). When the reaction was carried out under ambient atmosphere
(open to air), to our delight, we found that 2a was obtained in 57%
yield within 9.0 h using Pd(OAc)2 as the catalyst in the presence of
PPh3 and Et3N (Table 1, entry 15). Under this reaction conditions,
we also examined various ligands for palladium acetate such as
AsPPh3, N-heterocyclic carbene (NHC) as well as pyridine in the
presence of Et3N and the results of these experiments are shown in
entries 16–19. Only in the presence of pyridine, 2a was formed in
38% yield. Using Pd(OAc)2 as the catalyst under ambient atmo-
sphere, we also examined a variety of additives such as CuCl2,
benzoquinone, 1,4-naphthoquinone, and iodosobenzene diacetate
2. Results and discussion
The initial examination was performed by use of (E)-[2-(benz-
ylidene)cyclopropyl]methanol 1a (0.3 mmol) as the substrate upon
treatment with Pd(OAc)2 (0.03 mmol) and Et3N at 60 ꢀC in toluene,
and we found that the starting materials 1a disappeared rapidly
* Corresponding author. Fax: þ86 21 64166128.
E-mail address: mshi@mail.sioc.ac.cn (M. Shi).
0040-4020/$ – see front matter Ó 2009 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2009.02.028

M. Shi et al. / Tetrahedron 65 (2009) 3404–3408
3405
Table 1
Table 2
Optimization of the reaction conditions
Palladium-catalyzed ring opening and oxidation of 2-(arylmethylene)-
cyclopropylcarbinols 1
O
O
OH
OH
H
catalyst, additive
toluene, 60 °C, time
H
Pd(OAc)2, PPh3, Et3N
air, toluene, 60 °C
C6H5
R1
R2
C6H5
R1
1a
2a
1, R1 = Aryl, R2 = H
2, R1 = Aryl
Yieldb (%)
Entrya
Catalyst
Additive
Time
(h)
Yieldb (%)
Entrya
R1/R2
Time (h)
2a
1c
Pd(OAc)2
Pd(OAc)2
PdCl2
Et3N
d
4
11
12
5
24
6
43
d
d
42
d
42
d
d
d
d
d
d
d
d
57
d
d
2
2c
1
2
3
4
5
6
7
8
9
10
4-ClC6H4/H, 1b
4-BrC6H4/H, 1c
4-FC6H4/H, 1d
3-BnOC6H4/H, 1e
3-MeC6H4/H, 1f
6
10
7
3
8
3
3
3
6
2b, 58
d
3c
Et3N
d
4c
Pd(OAc)2/PPh3
Pd(PPh3)4/PPh3
Pd(OAc)2/PPh3
Pd(OAc)2/PPh3
Pd(OAc)2/PPh3
Pd(OAc)2/PPh3
Pd(OAc)2/PPh3
Pd(OAc)2/PPh3
Pd(OAc)2/PPh3
Pd(OAc)2/PPh3
Pd(OAc)2
2d, 42
2e, 64
2f, 62
2g, 67
2h, 64
2i, 65
2j, 57
d
5c
d
6c
Et3N
d
7d
7
3,4,5-(MeO)3C6H2/H, 1g
8d
Et3N
CuCl2$2H2O
DBU
Cs2CO3
tBuOK
AcONa
TMEDA
Et3N
30
30
24
24
24
24
24
9
2,5-(MeO)2C6H3/H, 1h
4-MeOC6H4/H, 1i
4-MeC6H4/H, 1j
H/C6H5, Z-1a
9d
10c
11c
12c
13c
14c
15e
16e
17e
8
a
All reactions were carried out with 1 (0.30 mmol), Pd(OAc)2 (0.03 mmol), PPh3
(0.18 mmol), and Et3N (0.30 mmol) in l.0 mL of toluene under air atmosphere.
b
Isolated yields.
Pd(OAc)2/PPh3
Pd(OAc)2/AsPh3
Pd(OAc)2/NHC
Et3N
Et3N
10
19
we found that the corresponding product 2a was obtained in 54%
yield (Scheme 1). This result clearly suggested that the proton in
hydroxyl group did not affect the reaction in this process. To
learn more mechanistic insight on the hydroxymethyl group, we
next carried out the deuterium labeling experiment by use of
MCP d2-1a as the substrate as shown in Scheme 2 under the
standard reaction conditions. It was found that the reaction be-
came sluggish to afford the corresponding d1-2a in 9% yield with
97% D content (kH/kD¼7.0), indicating that the oxidation of the
methylene proton in MCPs 1 should be the rate-determining
step.
N
N
18e
19e
20e
21e
22e
23e
Pd(OAc)2/Pyr
Pd(OAc)2/PPh3
Pd(OAc)2
Et3N
CuCl2$2H2O
BQ
1,4-NQ
Phl(OAc)2
Et3N
10
30
11
11
6
38
d
d
d
d
d
Pd(OAc)2
Pd(OAc)2/PPh3
Pd(dba)3/PPh3
6
a
All reactions were carried out with 1a (0.30 mmol), catalyst (0.03 mmol), ligand
(0.18 mmol), and additive (0.30 mmol, if needed) in l.0 mL of toluene at 60 ꢀC.
b
Isolated yields.
c
The reactions were carried out under argon atmosphere and the dissolved oxy-
gen in THF acted as an oxidant.
d
The reactions were carried out under oxygen atmosphere.
The reactions were carried out under ambient atmosphere.
O
e
OD
H
Pd(OAc)2, PPh3, Et3N
air, toluene, 60 °C
in this reaction and found that none of the formation of 2a could
be identified (Table 1, entries 19–22). Using Pd2(dba)3 as the cat-
alyst and PPh3 as the ligand, no reaction occurred in the presence
of Et3N (Table 1, entry 23). In other solvents such as 1,2-di-
chloroethane, acetonitrile or tetrahydrofuran (THF), the reaction
outcome is not as good as that carried out in toluene to give 2a in
<30% yields.
C6H5
C6H5
d1-1a
2a, 54%
Scheme 1. Deuterium labeling experiment.
D
With these optimal conditions being identified, we next exam-
ined the scope of this transformation. Substrates 1 whether bearing
electron-donating groups or electron-withdrawing groups on the
benzene ring underwent this ring opening and oxidation reaction
smoothly to provide the corresponding (2E,4E)-5-arylpenta-
2,4-dienals 2 in moderate to good yields (Table 2, entries 1, 3–9).
Only in the case of (E)-[2-(4-bromobenzylidene)cyclopropyl]me-
thanol 1c, none of the formation of the corresponding (2E,4E)-
5-arylpenta-2,4-dienal 2 could be identified, presumably due to
that the Pd(0) catalyst will promote an oxidative addition of bro-
mobenzene moiety in 1c and subsequently quench the active
species in this process (Table 2, entry 2). Moreover, using
(Z)-[2-(benzylidene)cyclopropyl]methanol (Z)-1a as the substrate
did not deliver the same product under the standard conditions,
presumably due to the steric hindrance (Table 2, entry 10).
To clarify the role of hydroxymethyl group in this trans-
formation, a control experiment using deuterated MCP d1-1a as
the substrate was carried out under the standard conditions, and
D
O
D
OH
Pd(OAc)2, PPh3, Et3N
air, toluene, 60 °C, 7 h
C6H5
C6H5
d1-2a, yield 9%,
d2-1a
D content 97%
Scheme 2. Deuterium labeling experiment.
On the basis of above deuterium labeling experiment, we en-
visaged that product 2 might be produced via the oxidation of the
in situ generated (E,E)-5-arylpenta-2,4-dien-1-ol 3 by air in the
presence of Pd(II) catalyst. To determine the reaction pathway, we
directly prepared the authentic sample (E,E)-5-phenylpenta-2,4-
dien-1-ol 3a using our previously reported Pd(0)-catalyzed
isomerization of 2-(arylmethylene)cyclopropylcarbinol 1 in the
presence of AcOH as shown in Scheme 3.4 We confirmed that 3a
can be indeed transformed to 2a under the standard reaction

3406
M. Shi et al. / Tetrahedron 65 (2009) 3404–3408
conditions in 59% yield, suggesting that compound 3 should be
the reaction intermediate (Scheme 4).
O
H
OH
OH
H
H
Pd(0)
Pd(II)/O2
Pd
2
3
Pd H
Ar
Ar
1
Ar
OH
Pd(0)
OH
B
A
Pd(PPh3)4, AcOH
dioxane, rt
Scheme 7. Proposed mechanism for transformation of 2-(arylmethylene)-
cyclopropylcarbinols 1 to dienals 2.
Ar
Ar
1
3
Scheme 3. Pd(0)-catalyzed isomerization of 2-(arylmethylene)cyclopropylcarbinol 1
in the presence of AcOH.
The structure of products 2 was determined by 1H, 13C NMR
spectroscopic data, MS, and HRMS analytic data as well as micro-
analyses. Moreover, their structures were unambiguously
determined by X-ray diffraction of product 2g and its CIF data have
been summarized in Supplementary data (Fig. 1).8
O
OH
H
In conclusion, we have developed a fairly efficient method for
the ring opening and oxidation of 2-(arylmethylene)cyclopro-
pylcarbinols 1 catalyzed by palladium(II) acetate in the presence of
triethylamine as well as triphenylphosphine. Substrates whether
bearing electron-donating groups or electron-withdrawing groups
on the benzene ring undergo this transformation smoothly to
provide (2E,4E)-5-arylpenta-2,4-dienals 2 in moderate to good
yields under mild conditions. Mechanisms involved with an in situ
generated Pd(0) species from Pd(II) and Et3N or PPh3 catalyzed
isomerization of 1 to provide (E,E)-5-arylpenta-2,4-dien-1-ols 3
and following a Pd(II) catalyzed aerobic oxidation of 3 have been
proposed on the basis of control and deuterium labeling experi-
ments. Efforts are in progress to elucidate further mechanistic
details of these reactions and to understand their scope and
limitations.
Pd(OAc)2, PPh3, Et3N
air, toluene, 60 °C, 6 h
C6H5
C6H5
3a
2a, 59%
Scheme 4. Oxidation of dienol 3a in the presence of Pd(OAc)2 and air.
Next, we carried out the reaction of 1a under rigorously deoxy-
genative condition by purging the dissolved molecular oxygen in
toluene through bubbling with argon and replacing the reaction
vessel with argon atmosphere under the standard reaction condi-
tions. It was found that 3a was obtained in 52% yield, indicating that
3a is indeed formed during the reaction process (Scheme 5).
OH
OH
Pd(OAc)2, PPh3, Et3N
Ar, toluene, 60 °C, 6 h
C6H5
C6H5
3a, 52%
3. Experimental section
3.1. General remarks
1a
Scheme 5. Reactions of 2-(phenylmethylene)cyclopropylcarbinol 1a in the presence of
Pd(OAc)2 under rigorously deoxygenative conditions.
Melting point instrument is uncorrected. 1H NMR spectra were
recorded on a Bruker AM-300 spectrometer for solution in CDCl3
with tetramethylsilane (TMS) as an internal standard; J-values are
in hertz. Mass spectra were recorded with a HP-5989 instrument.
Dichloromethane was distilled from CaH2 under Ar atmosphere.
Some of the solid compounds reported in this paper gave satis-
factory CHN microanalyses with a Carlo-Erba 1106 analyzer.
Commercially obtained reagents were used without further pu-
rification. All of the reactions were monitored by TLC plates
coated with Huanghai GF254 silica gel. Flash column chromatog-
raphy was carried out using 200–300 mesh silica gel at increased
pressure.
On the basis of above control experiments, we can conclude that
the formation of 2 proceeds through an in situ generated Pd(0)
5
species from Pd(II) and Et3N or PPh3 catalyzed isomerization of
MCP 1 to provide (E,E)-5-arylpenta-2,4-dien-1-ol 3 and following
a Pd(II) catalyzed aerobic oxidation of 3 to furnish the final product 2
(Scheme 6).6 Under oxygen atmosphere, Pd(0) species is hardly to be
produced and therefore, the initial ring-opening process does not
proceed at all. Furthermore, using Pd(0) as the catalyst, Pd(II) species
should be in a low concentration in the reaction system, rendering
that the oxidation of the formed 2,4-dien-1-ol 3 is impossible. Using
Pd(OAc)2 as the catalyst in the presence of Et3N and PPh3 under
ambient atmosphere, Pd(0) can initiate the isomerization of 1 togive
3 and Pd(II) can catalyze the aerobic oxidation of 3 to produce 2.
Pd(OAc)2, Et3N
O
OH
OH
H
Pd(0)
Pd(II)
air
Ar
Ar
3
Ar
1
2
Scheme 6. Proposed process for the transformation of 2-(arylmethylene)-
cyclopropylcarbinols 1 to dienals 2.
The mechanism for the formation of 3 is shown in Scheme 7 on
the basis of control and deuterium labeling experiments.
Intermediate A is first formed from 1 and Pd(0), which gives in-
termediate B through anti-
elimination of B produces 3 and regenerates Pd(0) species.
b
-hydrogen elimination.7 Reductive
Figure 1. ORTEP drawing of 2g.

M. Shi et al. / Tetrahedron 65 (2009) 3404–3408
3407
3.2. General procedure for the preparation of products 2
6.99–7.01 (m, 2H), 7.16–7.18 (m,1H), 7.23–7.32 (m, 4H, ArH), 9.62 (d,
J¼7.8 Hz, 1H); 13C NMR (CDCl3, 75 MHz, TMS):
d 21.2, 124.7, 125.9,
Compound 1 (0.30 mmol), Pd(OAc)2 (0.030 mmol), and PPh3
(0.18 mmol) were weighed into an oven-dried Schlenk tube, which
was charged with 1.0 mL of toluene. The reaction mixture was then
stirred under ambient atmosphere. Then, 0.30 mmol of triethylamine
(Et3N) was added into the reaction mixture bya syringe. The mixtures
were stirred and heated to 60 ꢀC. After completion of the trans-
formationsmonitoredbyTLCplates,thereactionmixturewasdirectly
transferred to silica gel column and eluted with mixtures of petro-
leum ether and ethyl acetate to afford the corresponding product 2.
128.0, 128.7, 130.4, 131.3, 135.4, 138.4, 152.1, 193.5; MS (EI) m/z (%):
172 (Mþ, 36.98), 157 (12.82), 143 (32.90), 129 (100.00), 128 (83.34),
115 (35.17), 91 (22.70), 65 (28.01), 63 (28.01), 51 (32.88); HRMS (EI)
Calcd for C12H12O 172.0888, found 172.0890.
3.2.6. (2E,4E)-5-(3,4,5-Trimethoxyphenyl)penta-2,4-dienal
Product 2g: R1¼3,4,5-(CH3O)3C6H2;
a yellow solid; mp
n 2999, 2939, 2925, 2828, 2745, 2722, 1946,
119–121 ꢀC; IR (film):
1671,1615,1578,1504,1467,1420,1392,1339,1246,1207,1149,1123,
1006, 988, 882, 843, 734, 574 cmꢁ1 1H NMR (CDCl3, 300 MHz,
TMS):
3.89 (s, 3H, CH3O), 3.92 (s, 6H, CH3O), 6.28 (dd, J¼15.0,
;
3.2.1. (2E,4E)-5-Phenylpenta-2,4-dienal
d
Product 2a: R1¼C6H5; a yellow liquid; IR (film):
n
3339, 3028,
8.1 Hz, 1H), 6.74 (s, 2H, ArH), 6.87–6.99 (m, 2H), 7.18–7.31 (m, 1H),
2822, 2741, 1954, 1674, 1619, 1591, 1492, 1449, 1417, 1389, 1266,
9.63 (d, J¼8.1 Hz, 1H); 13C NMR (CDCl3, 75 MHz, TMS):
d 55.9, 60.7,
1200, 1153, 1117, 1012, 986, 880, 845, 737, 560 cmꢁ1
(CDCl3, 300 MHz, TMS):
6.28 (dd, J¼15.0, 8.1 Hz,1H), 7.01–7.03 (m,
2H), 7.24–7.42 (m, 1H), 7.35–7.53 (m, 5H, ArH), 9.63 (d, J¼8.1 Hz,
;
1H NMR
104.4, 125.4, 130.98, 131.02, 139.4, 142.2, 151.9, 153.2, 193.4; MS (EI)
m/z (%): 248 (Mþ, 100.00), 233 (41.19), 219 (55.60), 188 (52.87), 145
(26.44), 115 (21.97), 91 (18.57), 65 (15.28). Anal. Calcd for C14H16O4:
C, 67.73; H, 6.50. Found: C, 67.54; H, 6.47.
d
1H); 13C NMR (CDCl3, 75 MHz, TMS):
d 126.0, 127.4, 128.8, 129.6,
131.4,135.4, 142.3, 152.0,193.5; MS (EI) m/z (%): 158 (Mþ, 51.64), 130
(36.67), 129 (00.00), 128 (63.03), 115 (29.76), 77 (25.31), 51 (30.63);
HRMS (EI) Calcd for C11H10O 158.0732, found 158.0739.
3.2.7. (2E,4E)-5-(2,5-Dimethoxyphenyl)penta-2,4-dienal
Product 2h: R1¼2,5-(CH3O)2FC6H3; a yellow solid; mp 73–75 ꢀC;
IR (film):
n 3001, 2944, 2835, 1676, 1612, 1493, 1466, 1428, 1293,
3.2.2. (2E,4E)-5-(4-Chlorophenyl)penta-2,4-dienal
1227, 1180, 1156, 1123, 1046, 1021, 988, 804, 717 cmꢁ1
;
1H NMR
Product 2b: R1¼4-ClC6H4; a yellow solid; mp 140–142 ꢀC; IR
(CDCl3, 300 MHz, TMS): 3.80 (s, 3H, CH3O), 3.84 (s, 3H, CH3O), 6.23
d
(film):
n
3032, 2926, 2829, 2744, 1897, 1675, 1622, 1588, 1490, 1408,
(dd, J¼15.0, 7.8 Hz, 1H), 6.82–6.90 (m, 2H), 6.96–7.07 (m, 2H), 7.25
1299, 1275, 1200, 1154, 1114, 1088, 1012, 989, 885, 836, 692,
(d, J¼15.0 Hz, 1H), 7.35 (d, J¼15.6 Hz, 1H), 9.58 (d, J¼7.5 Hz, 1H); 13C
583 cmꢁ1 1H NMR (CDCl3, 300 MHz, TMS):
;
d
6.28 (dd, J¼15.0,
NMR (CDCl3, 75 MHz, TMS): d 55.6, 56.0, 112.1, 112.2, 116.3, 125.0,
7.8 Hz, 1H), 6.97–6.99 (m, 2H), 7.21–7.30 (m, 1H), 7.34–7.37 (m, 2H,
126.7, 131.0, 137.4, 152.1, 153.1, 153.4, 193.7; MS (EI) m/z (%): 218
(Mþ, 100.00), 189 (34.71), 159 (47.82), 144 (49.41), 115 (69.02), 91
(33.51), 77 (45.12), 55 (40.00); HRMS (EI) Calcd for C13H14O3
218.0943, found 218.0935.
ArH), 7.43–7.45 (m, 2H, ArH), 9.63 (d, J¼7.8 Hz, 1H); 13C NMR
(CDCl3, 75 MHz, TMS): d 16.6, 128.5, 129.0, 131.8, 134.0, 135.2, 140.6,
151.4, 193.3; MS (EI) m/z (%): 192 (Mþ, 41.40), 157 (30.03), 129
(100.00), 128 (65.36), 127 (46.14), 75 (18.56), 51 (22.82); HRMS (EI)
Calcd for C11H9ClO 192.0342, found 192.0348.
3.2.8. (2E,4E)-5-(4-Methoxyphenyl)penta-2,4-dienal
Product 2i: R1¼4-CH3OC6H4; a yellow solid; mp 80–82 ꢀC; IR
3.2.3. (2E,4E)-5-(4-Fluorophenyl)penta-2,4-dienal
(film): n 3053, 3034, 2979, 2845, 2753, 1895, 1670, 1622, 1511, 1462,
Product 2d: R1¼4-FC6H4; a yellow solid; mp 81–83 ꢀC; IR
1423, 1402, 1256, 1197, 1177, 1154, 1113, 1017, 990, 839, 808, 737,
(film):
n
3382, 3037, 2848, 2767, 1943, 1897, 1678, 1621, 1591,
560 cmꢁ1; 1H NMR (CDCl3, 300 MHz, TMS):
d
3.85 (s, 3H, CH3O), 6.24
1509, 1467, 1418, 1399, 1266, 1233, 1197, 1155, 1122, 1015, 989,
(dd, J¼15.0, 8.1 Hz, 1H), 6.84–7.01 (m, 3H), 7.22–7.31 (m, 2H, ArH),
896, 841, 738, 552 cmꢁ1 1H NMR (CDCl3, 300 MHz, TMS):
;
d
6.27
7.44–7.48 (m, 2H, ArH), 9.60 (d, J¼8.1 Hz, 1H); 13C NMR (CDCl3,
(dd, J¼15.3, 7.8 Hz, 1H), 6.87–7.97 (m, 2H), 7.02–7.11 (m, 2H,
75 MHz, TMS): d 55.2, 114.2, 123.9, 128.2, 129.0, 130.3, 142.2, 152.7,
ArH), 7.22–7.30 (m, 1H), 7.47–7.52 (m, 2H, ArH), 9.62 (d,
160.8, 193.5; MS (EI) m/z (%): 188 (Mþ, 100.00), 159 (41.60), 144
(44.96),129 (29.94),117 (25.12),115 (51.39), 91 (24.80), 63 (22.37), 51
(18.46); HRMS (EI) Calcd for C12H12O2 188.0837, found 188.0834.
J¼7.8 Hz, 1H); 13C NMR (CDCl3, 75 MHz, TMS):
d 115.9, 116.1,
125.9 (d, J¼2.2 Hz), 129.2 (d, J¼8.7 Hz), 131.6 (d, J¼16.0 Hz),
140.9 (d, J¼2.2 Hz), 151.8, 163.4 (d, J¼249.6 Hz), 193.5; MS (EI)
m/z (%): 176 (Mþ, 100.00), 175 (31.52), 148 (53.95), 147 (93.48),
146 (61.57), 133 (44.99), 127 (38.34), 75 (27.62), 51 (26.34);
HRMS (EI) Calcd for C11H9FO 176.0637, found 176.0627.
3.2.9. (2E,4E)-5-p-Tolylpenta-2,4-dienal
Product 2j: R1¼4-CH3C6H4; a yellow solid; mp 96–98 ꢀC; IR
(film):
n 3050, 3006, 2981, 2847, 2767, 1915, 1667, 1618, 1512,
1453, 1420, 1398, 1266, 1198, 1184, 1155, 1122, 1018, 994, 836,
3.2.4. (2E,4E)-5-(3-(Benzyloxy)phenyl)penta-2,4-dienal
810, 738, 552 cmꢁ1 1H NMR (CDCl3, 300 MHz, TMS):
;
d
2.38 (s,
Product 2e: R1¼3-BnOC6H4; a yellow liquid; IR (film):
n
3064,
3H, CH3), 6.25 (dd, J¼15.3, 8.1 Hz, 1H), 6.91–7.04 (m, 2H), 7.19
(d, J¼7.8 Hz, 2H, ArH), 7.23–7.31 (m, 1H), 7.41 (d, J¼7.8 Hz, 2H,
ArH), 9.61 (d, J¼8.1 Hz, 1H); 13C NMR (CDCl3, 75 MHz, TMS):
3032, 2928, 2872, 1682, 1618, 1582, 1488, 1448, 1382, 1291, 1265,
1160, 1026, 989, 780, 738, 697 cmꢁ1 1H NMR (CDCl3, 300 MHz,
;
TMS):
d
5.80 (s, 2H, PhCH2O), 6.26 (dd, J¼15.3, 8.1 Hz, 1H), 6.96 (d,
d 21.3, 125.1, 127.4, 129.5, 130.9, 132.7, 139.9, 142.5, 152.4, 193.5;
J¼5.4 Hz, 2H), 7.10–7.45 (m, 10H), 9.60 (d, J¼8.1 Hz, 1H); 13C NMR
MS (EI) m/z (%): 172 (Mþ, 55.44), 157 (17.10), 143 (30.89), 129
(CDCl3, 75 MHz, TMS):
d
70.0, 113.5, 116.1, 120.5, 126.4, 127.4, 128.1,
(100.00), 128 (83.60), 127 (25.60), 115 (33.57), 91 (14.09), 77
128.6, 129.9, 131.6, 136.6, 136.9, 142.2, 152.0, 159.1, 193.6; MS (EI)
m/z (%): 264 (Mþ, 2.05), 149 (6.35), 92 (8.98), 91 (100.00), 65
(18.18), 57 (6.52), 51 (4.82), 43 (5.20), 41 (5.16); HRMS (EI) Calcd
for C18H16O2 264.1150, found 264.1140.
(13.58), 65 (13.82), 51 (14.69); HRMS (EI) Calcd for C11H12
172.0888, found 172.0887.
O
3.2.10. Synthesis of d1-1a
3.2.5. (2E,4E)-5-m-Tolylpenta-2,4-dienal
Product 2f: R1¼3-CH3C6H4; a yellow liquid; IR (film):
n 3026,
OH
OD
NaH
THF
D2O
2922, 2855, 2737, 1856, 1674, 1619, 1485, 1455, 1416, 1380, 1266,
Extraction
1154, 1119, 1011, 986, 874, 779, 737, 570 cmꢁ1
300 MHz, TMS):
2.38 (s, 3H, CH3), 6.26 (dd, J¼15.6, 7.8 Hz, 1H),
;
1H NMR (CDCl3,
Ph
Ph
1a
d1-1a
d

3408
M. Shi et al. / Tetrahedron 65 (2009) 3404–3408
Compound d1-1a: 1H NMR (CDCl3, 300 MHz, TMS)
d
0.76–0.88 (m,
included in the Supplementary data. This material is available free
of charge via the Internet at Website. Supplementary data associ-
ated with this article can be found in the online version at,
doi:10.1016/j.tet.2009.02.028.
1H), 1.55–1.63 (m, 1H), 1.77–1.83 (m, 1H), 3.49 (dd, J¼7.2, 11.1 Hz,
1H), 3.60 (dd, J¼6.3,11.1 Hz,1H), 6.75 (d, J¼1.5 Hz, 1H), 7.12–7.17 (m,
1H, ArH), 7.24 (d, J¼7.2 Hz, 2H, ArH), 7.45 (d, J¼7.2 Hz, 2H, ArH).
3.2.11. Synthesis of d2-1a
D
O
D
OH
OH
O
OH
LiAlD4
THF
PDC
DCM
Ag2O
H2O, C2H5OH
Ph
d2-1a, 58%
Ph
Ph
Ph
4a, 89%
1a
3a, 55%
References and notes
3.2.12. (E)-2-Benzylidenecyclopropanecarboxylic acid
Compound 4a: a colorless solid; mp 133–135 ꢀC; IR (film):
3028, 2920, 2843, 1681, 1448, 1369, 337, 1235, 1019, 940, 909, 867,
772, 739, 690, 666 cmꢁ1; 1H NMR (CDCl3, 300 MHz, TMS)
1.96–2.02
n
3054,
1. For reviews, see: (a) Binger, P.; Bu¨ch, H. M. Top. Curr. Chem. 1987, 135, 77–151; (b)
Goti, A.; Cordero, F. M.; Brandi, A. Top. Curr. Chem. 1996, 178, 1–91; (c) Brandi, A.;
Cicchi, S.; Cordero, F. M.; Goti, A. Chem. Rev. 2003, 103, 1213–1270; (d) Nakamura,
E.; Yamago, S. Acc. Chem. Res. 2002, 35, 867–877; (e) Nakamura, I.; Yamamoto, Y.
Adv. Synth. Catal. 2002, 344, 111–129; (f) Rubin, M.; Rubina, M.; Gevorgyan, V.
Chem. Rev. 2007, 107, 3117–3179; (g) Shao, L.-X.; Shi, M. Curr. Org. Chem. 2007, 11,
1135–1153.
2. For the preparation of 2-(arylmethylene)cyclopropylcarbinols. See: (a) Turcant,
A.; Corre, L. M. Tetrahedron Lett. 1976, 17, 1277–1280; (b) Corre, L. M.; Hercouet,
A.; Bessieres, B. J. Org. Chem. 1994, 59, 5483–5484.
3. (a) Tian, G.-Q.; Shi, M. Org. Lett. 2007, 9, 2405–2408; (b) Tian, G.-Q.; Shi, M. Org.
Lett. 2007, 9, 4917–4920; (c) Shao, L.-X.; Qi, M.-H.; Shi, M. Tetrahedron Lett. 2008,
49, 165–168; (d) Shi, M.; Tian, G.-Q. Tetrahedron Lett. 2006, 47, 8059–8062; (e)
Tian, G.-Q.; Li, J.; Shi, M. J. Org. Chem. 2008, 73, 673–677; (f) Tian, G.-Q.; Yuan,
Z.-L.; Zhu, Z.-B.; Shi, M. Chem. Commun. 2008, 2668–2670; (g) Qi, M.-H.; Shao,
L.-X.; Shi, M. Synthesis 2007, 3567–3573; (h) Shi, M.; Jiang, M.; Liu, L.-P. Org.
Biomol. Chem. 2007, 5, 438–440.
d
(m, 1H), 2.15–2.18 (m, 1H), 2.33–2.35 (m, 1H), 6.84 (s, 1H), 7.22–7.27
(m,1H, ArH), 7.33–7.36 (m, 2H, ArH), 7.49 (d, J¼7.2 Hz, 2H, ArH),11.34
(br s, 1H). 13C NMR (CDCl3, 75 MHz):
d 11.4, 15.9, 120.1, 122.6, 127.1,
127.7, 136.3, 179.1; MS (EI) m/z (%):174 (Mþ, 14.38), 130 (15.39), 119
(100.009),128 (64.65),127 (21.78),115 (21.66), 91 (24.28), 44 (62.77),
43 (27.44); HRMS Calcd for C11H10O 174.0681, found 174.0686.
Compound d1-2a: 1H NMR (CDCl3, 300 MHz, TMS)
d 6.27 (d,
J¼14.7 Hz, 1H), 7.00–7.02 (m, 2H), 7.23–7.32 (m, 2H), 7.35–7.42 (m,
3H, ArH), 7.50–7.53 (m, 2H, ArH).
Acknowledgements
4. Shi, M.; Wang, B.-Y.; Shao, L.-X. Synlett 2007, 909–912.
5. For the generation of Pd(0) species form Pd(II) complex in the presence of PPh3
or Et3N. (a) Bates, R. W.; Boonsombat, J. J. Chem. Soc., Perkin Trans. 1 2001,
654–656; (b) Batey, R. A.; Shen, M.; Lough, A. J. Org. Lett. 2002, 4, 1411–1414; (c)
Hegedus, L. S.; Allen, G. F.; Waterman, E. L. J. Am. Chem. Soc. 1976, 98, 2674–2676.
6. For the oxidation of allylic alcohol with Pd(II) in the presence of oxygen.
Peterson, K. P.; Larock, R. C. J. Org. Chem. 1998, 63, 3185–3189.
We thank the Shanghai Municipal Committee of Science and
Technology (06XD14005, 08dj1400100-2), National Basic Research
Program of China (973)-2009CB825300, and the National Natural
Science Foundation of China (20872162, 20672127, 20821002, and
20732008).
7. Liu, G.; Stahl, S. S. J. Am. Chem. Soc. 2007, 129, 6328–6335 and references therein.
8. The crystal data of 2g have been deposited in CCDC with number 281635. Em-
pirical formula: C14H16O4; formula weight: 248.27; crystal color, habit: colorless,
prismatic; crystal dimensions: 0.517ꢂ0.505ꢂ0.397 mm; crystal system: mono-
clinic; lattice type: primitive; lattice parameters: a¼10.869(2) Å, b¼14.124(3) Å,
Supplementary data
The spectroscopic data (1H, 13C spectroscopic data), HRMS of the
compounds shown in Tables 1 and 2 and the X-ray crystal data of 2g
along with the detailed description of experimental procedures are
c¼17.504(3) Å,
a
¼90ꢀ,
b
¼103.901(3)ꢀ,
g
¼90ꢀ, V¼2608.5(9) Å3; space group:
P2(1)/c; Z¼8; Dcalcd¼1.264 g/cm3; F000¼1056; diffractometer: Rigaku AFC7R;
residuals: R; wR: 0.0660, 0.1582.