Sm/HOAc/EtOH system-mediated reduction of Baylis-Hillman acetates

Article abstract of DOI:10.1080/00397910701577570

Selective formation of (2E)-2-methylalk-2-enoates or 2-methyl alkanoates could be achieved in moderate to good yields under mild conditions via Sm/HOAc/EtOH system-mediated reduction of Baylis-Hillman acetates depending on the amount of samarium consumed in the reactions. Copyright Taylor & Francis Group, LLC.

Full text of DOI:10.1080/00397910701577570

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Sm/HOAc/EtOH System–Mediated Reduction of
Baylis–Hillman Acetates
Yunkui Liu a , Dajie Mao a , Danqian Xu a , Zhenyuan Xu a & Yongmin Zhang b
a State Key Laboratory Breeding Base of Green Chemistry—Synthesis
Technology, Zhejiang University of Technology , Hangzhou, China
b Department of Chemistry , Zhejiang University , Hangzhou, China
Published online: 14 Dec 2007.
To cite this article: Yunkui Liu , Dajie Mao , Danqian Xu , Zhenyuan Xu & Yongmin Zhang (2007) Sm/
HOAc/EtOH System–Mediated Reduction of Baylis–Hillman Acetates, Synthetic Communications: An
International Journal for Rapid Communication of Synthetic Organic Chemistry, 37:24, 4389-4397, DOI:
10.1080/00397910701577570
To link to this article: http://dx.doi.org/10.1080/00397910701577570
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Synthetic Communicationsw, 37: 4389–4397, 2007
Copyright # Taylor & Francis Group, LLC
ISSN 0039-7911 print/1532-2432 online
DOI: 10.1080/00397910701577570
Sm/HOAc/EtOH System–Mediated
Reduction of Baylis–Hillman Acetates
Yunkui Liu, Dajie Mao, Danqian Xu, and Zhenyuan Xu
State Key Laboratory Breeding Base of Green Chemistry—Synthesis
Technology, Zhejiang University of Technology, Hangzhou, China
Yongmin Zhang
Department of Chemistry, Zhejiang University, Hangzhou, China
Abstract: Selective formation of (2E)-2-methylalk-2-enoates or 2-methyl alkanoates
could be achieved in moderate to good yields under mild conditions via Sm/HOAc/
EtOH system–mediated reduction of Baylis–Hillman acetates depending on the
amount of samarium consumed in the reactions.
Keywords: Baylis–Hillman acetates, (2E)-2-methylalk-2-enoates, 2-methyl alkano-
ates, selective, Sm/HOAc/EtOH system
As a powerful one-electron transfer reductant, samarium diiodide (SmI2) has
been extensively applied in organic synthesis in recent decades.[1] Although
SmI2 is a useful reductive reagent, its application in organic synthesis is
limited to some extent. For example, it is expensive and needs delicate
treatment and careful storage because it is very sensitive to air oxidation. In
addition, it gives only one electron in the reaction, which seriously restricts
its large-scale application. On the other hand, the readily available and low-
cost metallic samarium is stable in air and has strong reducing power
(Sm3þ/Sm ¼ 22.41 V), which is comparable with that of magnesium
Received December 21, 2006
Address correspondence to Zhenyuan Xu, State Key Laboratory Breeding Base of
Green Chemistry—Synthesis Technology, Zhejiang University of Technology,
Hangzhou 310014, China. E-mail: greensyn@zjut.edu.cn
4389

4390
Y. Liu et al.
(Mg2þ/Mg ¼22.37 V) and superior to that of zinc (Zn2þ/Zn ¼ 20.71 V).
Moreover, metallic samarium gives more electrons (theoretically three
electrons) in reactions than SmI2 does. Therefore, recently, growing interest
has been focused on the direct use of metallic samarium as a reducing agent
in various organic transformations.[2]
The Baylis–Hillman reaction is a versatile carbon–carbon bond-formation
reaction in organic synthesis.[3] The reaction provides adducts possessing
hydroxyl group, alkenyl, and electron-withdrawing groups in close proximity,
which makes it valuable in a number of stereoselective processes.[3] Among
these transformations, the preparation of (2E)-2-methylalk-2-enoates[4] from
the adducts 3-hydroxy-2-methylene-alkanoates (derived from acrylate esters)
or their derivatives has drawn much attention as these compounds usually
have biological activities or serve as important building blocks for bioactive
molecules.[5] A variety of reducing agents have been applied for this purpose
[e.g., low-valent titanium,[4a] SmI2,[4b] NaBH4,[4c,d] LiAlH4,[4e] LiBEt3H,[4f]
polymethylhydrosiloxane-B(C6F5)3 (cat.) system,[4g] palladium catalysts in
combination with phosphorus ligands,[4h] etc]. However, some limitations are
still found in the reported methods with regard to operational convenience,
reaction conditions, ready availability of reducing agents, and toxicity of
reagents. In continuation of our interest in the application of Baylis–Hillman
adducts in organic synthesis,[6] we report herein an efficient and convenient
way for selective formation of (2E)-2-methylalk-2-enoates or 2-methyl alkano-
ates in good to high yields under mild conditions via Sm/HOAc/EtOH
system[7]–mediated reduction of Baylis–Hillman acetates depending on the
amount of samarium consumed in the reactions (Scheme 1).
Initially, Baylis–Hillman acetate 1a (1.0 equiv.) was treated with
samarium (1.5 equiv.), glacial acetic acid (0.5 mL), and ethanol (2 mL) at
room temperature for 1 h under a nitrogen atmosphere. (E)-Methyl
2-methyl-3-phenylacrylate 2a could be isolated in 81% yield along with a
small amount of methyl 2-methyl-3-phenylpropanoate 4a (in 7% yield)
(Table 1, entry 1). The reaction could be carried out in open air without the
protection of nitrogen atmosphere and still gave a good yield of product,
Scheme 1.

Baylis–Hillman Acetates
4391
Table 1. Selective preparation of (2E)-2-methylalk-2-enoates 2 or 2-methyl alkanoates
4 from Baylis–Hillman acetates
Yield (%)a
Sm
(equiv.)
Time
(h)
Entry
R
2b
4
1
2
C6H5 (1a)
C6H5 (1a)
C6H5 (1a)
1.5/3.0
1.5
1.5
1/4
4
81 (80c)/—d
43e
7/85
Trace
Trace
10/84
9/79
12/82
13/78
10/82
11/83
80
3
4
12f
4
4-CH3C6H4 (1b)
2-CH3OC6H4 (1c)
4-CH3OC6H4 (1d)
3,4-OCH2OC6H3 (1e)
2-ClC6H4 (1f)
1.5/3.0
1.5/3.0
1.5/3.0
1.5/3.0
1.5/3.0
1.5/3.0
3.0
1/4
1/4
1/4
1/4
1/4
1/4
4
78/–d
74/—d
75/—d
73/—d
76/—d
75/—d
5
6
7
8
9
4-ClC6H4 (1g)
d
10
11
12
2,4-Cl2C6H3 (1h)
C6H5CH2CH2 (1i)
n-C7H15 (1j)
—
—
d
3.0
1.5/3.0
4
75
12/74
3/7
65/—d
aIsolated yields.
bAll products were E-isomer.
cThe reaction was carried out in open air.
dNot isolated.
eTHF was used as solvent.
f0.5 mL water was added into the reaction mixture.
which adds much convenience to the procedure (entry 1). When THF was used
as solvent instead of ethanol, the reaction proceeded more slowly and gave a
reduced yield of 2a (entry 2). An attempt to run the reaction in aqueous media
(by addition of 0.5 mL of water into the reaction mixture) did not succeed
because of the poor yield of the product (entry 3). The experimental results
showed that the present method was effective for substrates possessing
either aryl groups or alkyl substituents, although the reaction required a
longer time for alkyl-substituted 1 and gave lower yields of products
(entries 1, 4–9, 12). Among substrates bearing aryl groups, there is not
much difference between those containing electron-donating and electron-
withdrawing functionalities with respect to reaction times and yields of
products. In all cases, no regioisomer 3 and Z-isomer of 2 were detected,
suggesting the present process is highly regio- and stereoselective.
Next, realizing that 4 were the further reduction products of 2, we reasoned
that increasing the amount of samarium in the reaction would give 4 as the major
products, thus providing a convenient way to synthesize 2-methyl alkanoates[8]
from Baylis–Hillman acetates. Indeed, when up to 3 equiv. samarium were
consumed, the Sm/HOAc/EtOH system–mediated reduction of 1 finally gave
4 as the exclusive products in moderate to good yields. The reaction showed
high regioselectivity; only 4 were isolated as sole products, and reductive

4392
Y. Liu et al.
dimerized products of 2 (5) found in the Sm/Al/MeOH system[9]–mediated
reduction of methyl cinnamate and reduction products of ester groups were not
detected. A variety ofBaylis–Hillmanacetatesincludingarylgroups(possessing
either electron-donating or electron-withdrawing substituents) and alkyl ones
were tested to establish the generality. In all cases, the reaction proceeded
smoothly and gave 4 in moderate to good yields.
In summary, the Sm/HOAc/EtOH system–mediated reduction of
Baylis–Hillman acetates offers a convenient and efficient method for the
selective preparation of (2E)-2-methylalk-2-enoates or 2-methyl alkanoates
in moderate to good yields under mild conditions. The advantages of this
method are readily available starting materials, simple operational procedures,
and mild reaction conditions.
EXPERIMENTAL
1H NMR spectra were obtained on a Bruker AC 400 (400-MHz) instrument in
CDCl3 using TMS as internal standard. 13C NMR spectra were measured in
CDCl3 and recorded on a Bruker AC-100 spectrometer with TMS as internal
standard. Chemical shifts (d) are expressed in parts per million (ppm), and
coupling constants J are given in hertz. IR spectra were taken with a Bruker
Victor 22 spectrometer. Mass spectra were obtained on a HP 5989B mass spec-
trometer. Elemental analyses were performed on an EA-1110 instrument.
General Procedure for the Selective Preparation of (2E)-2-
Methylalk-2-enoates (2) or 2-Methyl alkanoates (4) from
Baylis–Hillman Acetates
Samarium powder (0.23 g, 1.5 mmol for 2; 0.45 g, 3.0 mmol for 4), glacial
acetic acid (0.5 mL), ethanol (2 mL), and Baylis–Hillman acetates 1
(1 mmol) were placed in a 25-mL, three-necked flask, and the mixture was
stirred at room temperature for the given time in Table 1. The mixture was
filtered to remove the remaining samarium. Then the filtrate was extracted
with diethyl ether (30 mL ꢀ 3). The organic layer was washed with brine
(20 mL ꢀ 2) and dried over MgSO4. The solvent was removed under
reduced pressure to give the crude product, which was purified by preparative
thin-layer chromatography (TLC) on silica gel using cyclohexane–ethyl
acetate (6:1) as eluent.
Data
(E)-Methyl 2-methyl-3-phenylacrylate (2a):[4b] oil. IR (film): n 1712
1
(C55O), 1609 (C55C) cm21. H NMR (400 MHz, CDCl3): d 2.18 (s, 3H),
3.88 (s, 3H), 7.35–7.45 (m, 5H), 7.77 (s, 1H). MS: m/z (%) 176 (Mþ).

Baylis–Hillman Acetates
4393
(E)-Methyl 2-methyl-3-(4-methylphenyl)acrylate (2b):[4b] oil. IR (film) n
1713 (C55O), 1630 (C55C) cm21 1H NMR (400 MHz, CDCl3): d 2.10
.
(s, 3H), 2.35 (s, 3H), 3.80 (s, 3H), 7.20 (d, 2H, J ¼ 8.0 Hz), 7.32 (d, 2H,
J ¼ 8.0 Hz), 7.68 (s, 1H). MS: m/z (%) 190 (Mþ).
(E)-Methyl 3-(2-methoxyphenyl)-2-methylacrylate (2c):[4b] oil. IR (film) n
.
1712 (C55O), 1600 (C55C) cm21 1H NMR (400 MHz, CDCl3): d 2.08
(s, 3H), 3.82 (s, 3H), 3.86 (s, 3H), 6.90–7.36 (m, 4H), 7.85 (s, 1H). MS: m/z
(%) 206 (Mþ).
(E)-Methyl 3-(4-methoxyphenyl)-2-methylacrylate (2d):[4b] oil. IR (film) n
.
1711 (C55O), 1610 (C55C) cm21 1H NMR (400 MHz, CDCl3): d 2.12
(s, 3H), 3.81 (s, 3H), 3.83 (s, 3H), 6.93 (d, 2H, J ¼ 8.0 Hz), 7.39 (d, 2H,
J ¼ 8.0 Hz), 7.65 (s, 1H). MS: m/z (%) 206 (Mþ).
(E)-Methyl 3-(3-(benzo[1,3]dioxol-5-yl)-2-methylacrylate (2e):[4b] white
solid, mp: 75–768C. IR (KBr) n 1693 (C55O), 1600 (C55C) cm21 1H
.
NMR (400 MHz, CDCl3): d 2.11 (s, 3H), 3.82 (s, 3H), 5.99 (s, 2H), 6.83–
6.95 (m, 3H), 7.60 (s, 1H). MS: m/z (%) 220 (Mþ).
(E)-Methyl 3-(2-chlorophenyl)-2-methylacrylate (2f):[4b] oil. IR (film) n 1718
(C55O), 1635 (C55C) cm21. 1H NMR (400 MHz, CDCl3): d 2.03 (s, 3H), 3.86
(s, 3H), 7.27–7.49 (m, 4H), 7.79 (s, 1H). MS: m/z (%) 210 (Mþ).
(E)-Methyl 3-(4-chlorophenyl)-2-methylacrylate (2g):[4b] oil. IR (film) n
.
1715 (C55O), 1632 (C55C) cm21 1H NMR (400 MHz, CDCl3): d 2.10
(s, 3H), 3.81 (s, 3H), 7.31 (d, 2H, J ¼ 8.0 Hz), 7.35 (d, 2H, J ¼ 8.0 Hz),
7.63 (s, 1H). MS: m/z (%) 210 (Mþ).
(E)-Methyl 2-methyldec-2-enoate (2j): oil. IR (film) n 1717 (C55O), 1650
(C55C) cm21. 1H NMR (400 MHz, CDCl3): d 0.88 (s, 3H, J ¼ 7.2 Hz), 1.20–
1.46 (m, 10H), 1.83 (s, 3H), 2.16 (q, 2H, J ¼ 7.6 Hz), 3.73 (s, 3H), 6.77 (t, 1H,
J ¼ 7.6 Hz). 13C NMR (100 MHz, CDCl3): d 12.29, 14.03, 22.60, 28.54,
28.63, 29.08, 29.29, 31.74, 51.59, 127.33, 142.82, 168.75. MS: m/z (%) 198
(Mþ). Anal. calcd. for C12H22O2: C, 72.68; H, 11.18. Found: C, 72.24; H, 11.25.
Methyl 2-methyl-3-phenylpropanoate (4a):[8c] oil. IR (film) n 1738 (C55O)
cm21. 1H NMR (400 MHz, CDCl3): d 1.15 (d, 3H, J ¼ 6.4 Hz), 2.65 (dd, 1H,
1J ¼ 7.6 Hz, 2J ¼ 13.2 Hz), 2.73 (m, 1H), 3.02 (dd, 1H, 1J ¼ 6.4 Hz,
2J ¼ 13.2 Hz), 3.63 (s, 3H), 7.14–7.29 (m, 5H). 13C NMR (100 MHz,
CDCl3): d 16.69, 39.66, 41.37, 51.52, 126.27, 128.31, 128.91, 139.30,
176.50. MS: m/z (%) 178 (Mþ).
Methyl 2-methyl-3-(4-methylphenyl)propanoate (4b): oil. IR (film) n 1739
(C55O) cm21. 1H NMR (400 MHz, CDCl3): d 1.13 (d, 3H, J ¼ 6.8 Hz), 2.30

4394
Y. Liu et al.
(s, 3H), 2.61 (dd, 1H, 1J ¼ 8.0 Hz, 2J ¼ 13.2 Hz), 2.70 (m, 1H), 2.98 (dd, 1H,
1J ¼ 6.8 Hz, 2J ¼ 13.2 Hz), 3.63 (s, 3H), 7.03 (d, 2H, J ¼ 8.0 Hz), 7.07
(d, 2H, J ¼ 8.0 Hz). 13C NMR (100 MHz, CDCl3): d 16.60, 20.91, 39.20,
41.39, 51.42, 128.73, 128.95, 135.65, 136.14, 176.51. MS: m/z (%) 192
(Mþ). Anal. calcd. for C12H16O2: C, 74.97; H, 8.39. Found: C, 74.66; H, 8.35.
Methyl 3-(2-methoxyphenyl)-2-methylpropanoate (4c): oil. IR (film) n 1738
1
(C55O) cm21. H NMR (400 MHz, CDCl3): d 1.14 (d, 3H, J ¼ 7.6 Hz), 2.70
(dd, 1H, 1J ¼ 7.6 Hz, 2J ¼ 13.2 Hz), 2.82 (m, 1H), 2.98 (dd, 1H, 1J ¼ 6.4 Hz,
2J ¼ 13.2 Hz), 3.60 (s, 3H), 3.78 (s, 3H), 6.78–6.87 (m, 2H), 7.05–7.20
(m, 2H). 13C NMR (100 MHz, CDCl3): d 16.80, 34.39, 39.29, 51.23, 54.98,
110.03, 120.09, 127.52, 130.64, 157.46, 176.82. MS: m/z (%) 208 (Mþ). Anal.
calcd. for C12H16O3: C, 69.21; H, 7.74. Found: C, 69.60; H, 7.79.
Methyl 3-(4-methoxyphenyl)-2-methylpropanoate (4d): oil. IR (film) n 1738
(C55O) cm21. 1H NMR (400 MHz, CDCl3): d 1.13 (d, 3H, J ¼ 6.8 Hz), 2.58–
1
2
2.70 (m, 2H), 2.95 (dd, 1H, J ¼ 6.8 Hz, J ¼ 13.2 Hz), 3.63 (s, 3H), 3.78
(s, 3H), 6.81 (d, 2H, J ¼ 8.0 Hz), 7.07 (d, 2H, J ¼ 8.0 Hz). 13C NMR
(100 MHz, CDCl3): d 16.64, 38.85, 41.59, 51.45, 55.14, 113.73, 129.85,
131.36, 158.12, 176.54. MS: m/z (%) 208 (Mþ). Anal. calcd. for C12H16O3:
C, 69.21; H, 7.74. Found: C, 69.63; H, 7.78.
Methyl 3-(benzo[1,3]dioxol-5-yl)-2-methylpropanoate (4e): oil. IR (film) n
1735 (C55O) cm21. 1H NMR (400 MHz, CDCl3): d 1.14 (d, 3H, J ¼ 6.8 Hz),
1
2
2.56–2.69 (m, 2H), 2.93 (dd, 1H, J ¼ 6.4 Hz, J ¼ 11.2 Hz), 3.64 (s, 3H),
5.91 (s, 2H), 6.59–6.72 (m, 3H). 13C NMR (100 MHz, CDCl3): d 16.61,
39.38, 41.56, 51.46, 100.75, 108.04, 109.21, 121.81, 133.05, 145.98,
147.53, 176.33. MS: m/z (%) 222 (Mþ). Anal. calcd. for C12H14O4: C,
64.85; H, 6.35. Found: C, 64.38; H, 6.29.
Methyl 3-(2-chlorophenyl)-2-methylpropanoate (4f): oil. IR (film) n 1739
(C55O) cm21
.
1H NMR (400 MHz, CDCl3): d 1.18 (d, 3H, J ¼ 6.4 Hz),
1
2
2.79–2.91 (m, 2H), 3.11 (dd, 1H, J ¼ 6.8 Hz, J ¼ 12.8 Hz), 3.63 (s, 3H),
7.14–7.21 (m, 3H), 7.32–7.35 (m, 1H). 13C NMR (100 MHz, CDCl3): d
16.94, 37.30, 39.42, 51.58, 126.61, 127.85, 129.53, 131.24, 134.19, 137.03,
176.36. MS: m/z (%) 212 (Mþ). Anal. calcd. for C11H13ClO2: C, 62.12; H,
6.16. Found: C, 62.35; H, 6.19.
Methyl 3-(4-chlorophenyl)-2-methylpropanoate (4g): oil. IR (film) n 1741
(C55O) cm21. 1H NMR (400 MHz, CDCl3): d 1.15 (d, 3H, J ¼ 6.0 Hz), 2.61–
1
2
2.75 (m, 2H), 2.97 (dd, 1H, J ¼ 6.8 Hz, J ¼ 12.8 Hz), 3.63 (s, 3H), 7.08
(d, 2H, J ¼ 8.0 Hz), 7.23 (d, 2H, J ¼ 8.0 Hz). 13C NMR (100 MHz,
CDCl3): d 16.70, 38.90, 41.23, 51.52, 128.38, 130.20, 132.03, 137.72,
176.10. MS: m/z (%) 212 (Mþ). Anal. calcd. for C11H13ClO2: C, 62.12; H,
6.16. Found: C, 62.38; H, 6.11.

Baylis–Hillman Acetates
4395
Methyl 3-(2,4-dichlorophenyl)-2-methylpropanoate (4h): oil. IR (film) n
1738 (C55O) cm21 1H NMR (400 MHz, CDCl3): d 1.18 (d, 3H,
.
1
2
J ¼ 6.4 Hz), 2.76–2.85 (m, 2H), 3.06 (dd, 1H, J ¼ 6.0 Hz, J ¼ 12.4 Hz),
3.62 (s, 3H), 7.05–7.24 (m, 2H), 7.34 (s, 1H). 13C NMR (100 MHz,
CDCl3): d 16.93, 36.63, 39.26, 51.54, 126.82, 129.20, 131.90, 132.76,
134.75, 135.58, 175.94. MS: m/z (%) 246 (Mþ). Anal. calcd. for
C11H12Cl2O2: C, 53.46; H, 4.89. Found: C, 53.80; H, 4.92.
Methyl 2-methyl-5-phenylpentanoate (4i): oil. IR (film) n 1738 (C55O)
1
cm21. H NMR (400 MHz, CDCl3): d 1.14 (d, 3H, J ¼ 7.6 Hz), 1.43–1.50
(m, 1H), 1.57–1.73 (m, 3H), 2.40–2.50 (m, 1H), 2.61 (t, 2H, J ¼ 7.2 Hz),
3.66 (s, 3H), 7.15–7.29 (m, 5H). 13C NMR (100 MHz, CDCl3): d 17.06,
29.07, 33.37, 35.73, 39.32, 51.48, 125.73, 128.28, 128.34, 142.15, 177.17.
MS: m/z (%) 206 (Mþ). Anal. calcd. for C13H18O2: C, 75.69; H, 8.80.
Found: C, 76.01; H, 8.75.
Methyl 2-methyldecanoate (4j): oil. IR (film) n 1739 (C55O) cm21. 1H NMR
(400 MHz, CDCl3): d 0.88 (t, 3H, J ¼ 6.6 Hz), 1.14 (d, 3H, J ¼ 6.8 Hz),
1.20–1.47 (m, 14H), 2.40–2.46 (m, 1H), 3.67 (s, 3H). 13C NMR (100 MHz,
CDCl3): d 14.02, 17.00, 22.60, 27.19, 29.20, 29.40, 29.46, 31.80, 33.78,
39.40, 51.35, 177.33. MS: m/z (%) 200 (Mþ). Anal. calcd. for C12H24O2:
C, 71.95; H, 12.08. Found: C, 71.63; H, 12.03.
ACKNOWLEDGMENT
The authors are grateful to the Opening Foundation of Zhejiang Provincial
Top Key Discipline for financial support.
REFERENCES
1. (a) Girard, P.; Namy, J. L.; Kagan, H. B. Divalent lanthanide derivatives in organic
synthesis 1: mild preparation of samarium iodide and use as reducing or coupling
agents. J. Am. Chem. Soc. 1980, 102, 2693–2698; (b) Krief, A.; Laval, A. M.
Coupling of organic halides with carbonyl compounds promoted by SmI2, the
Kagan reagent. Chem. Rev. 1999, 99, 745–777; (c) Molander, G. A. Diverse
methods for medium ring synthesis. Acc. Chem. Res. 1998, 31, 603–609;
(d) Molander, G. A.; Harris, C. R. Sequenced reactions with samarium (II)
iodide. Tetrahedron 1998, 54, 3321–3354; (e) Molander, G. A.; Harris, C. R.
Sequencing reactions with samarium (II) iodide. Chem. Rev. 1996, 96,
307–338; (f) Molander, G. A. Application of lanthanide reagents in organic
synthesis. Chem. Rev. 1992, 92, 29–68.
2. Banik, B. K. Samarium metal in organic synthesis. Eur. J. Org. Chem. 2002,
2431–2444.

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Y. Liu et al.
3. For reviews, see (a) Basavaiah, D.; Rao, P. D.; Hyma, R. S. The Baylis–Hillman
reaction: a novel carbon–carbon bond forming reaction. Tetrahedron 1996, 52,
8001–8062; (b) Basavaiah, D.; Rao, A. J.; Satyanarayana, T. Recent advances
in the Baylis–Hillman reaction and applications. Chem. Rev. 2003, 103, 811–891.
4. (a) Shadakshari, U.; Nayak, S. K. Reductive dehydroxylation of Baylis–Hillman
adducts with low-valent titanium reagent: Syntheses of stereoselective trisubsti-
tuted alkenes. Tetrahedron 2001, 57, 4599–4602; (b) Li, J.; Qian, W. X.;
Zhang, Y. M. SmI2-mediated elimination reaction of Baylis–Hillman adducts con-
trolled by temperature: a facile synthesis of trisubstituted alkenes and 1,5-
hexadiene derivatives with E-stereoselectivity. Tetrahedron 2004, 60,
5793–5798; (c) Basavaiah, D.; Krishnamacharyulu, M.; Hyma, R. S.;
Sarma, P. K. S.; Kumaragurubaran, N. A facile one-pot conversion of acetates
of the Baylis–Hillman adducts to [E]-a-methulenecinnamic acids. J. Org.
Chem. 1999, 64, 1197–1200; (d) Das, B.; Banerjee, J.; Majhi, A.; Mahender, G.
An efficient stereoselctive synthesis of (E)- and (Z)-trisubstituted alkenes from
.
unactivated Baylis–Hillman adducts using NaBH4/CuCl2 2H2O. Tetrahedron
Lett. 2004, 45, 9225–9227; (e) Basavaiah, D.; Sarma, P. K. S. Applications of
Baylis–Hillman coupling products: a remarkable reversal of stereochemistry
from esters to nitriles: A simple synthesis of (2E)-2-methylalk-2-en-1-ols and
(2Z)-2-methylalk-2-enenitriles. J. Chem. Soc., Chem. Commun. 1992, 555–956;
(f) Hoffmann, H. M. R.; Rabe, J. DABCO-catalyzed coupling of aldehydes with
activated double bonds, 4: Stereoselective synthesis of trisubstituted olefins and
terpenoid building blocks via 2-(hydroxyalkyl)-2-propenoic esters. J. Org.
Chem. 1985, 50, 3849–3859; (g) Chandrasekhar, S.; Chandrashekar, G.;
Vijeender, K.; Reddy, M. S. Synthesis of trisubstituted alkenes by reductive
dehydroxylation of Baylis–Hillaman adducts using polymethylhydrosiloxane
(PMHS) and catalytic B(C6F5)3. Tetrahedron Lett. 2006, 47, 3475–3478;
(h) Pachamuthu, K.; Vankar, Y. D. Palladium catalysed region and steroselective
reduction of Baylis–Hillman coupling products derived allylic acetates. Tetra-
hedron Lett. 1998, 39, 5439–5442.
5. (a) Senokuchi, K.; Nakai, H.; Nakayama, Y.; Odagaki, Y.; Sakaki, K.; Kato, M.;
Maruyama, T.; Miyazaki, T.; Ito, H.; Kamiyasu, K.; Kim, S.; Kawamura, M.;
Hamanaka, N. New orally active serine protease inhibitors: structural requirements
for their good oral activity. J. Med. Chem. 1995, 38, 4508–4517;
(b) Senokuchi, K.; Nakai, H.; Nakayama, Y.; Odagaki, Y.; Sakaki, K.; Kato, M.;
Maruyama, T.; Miyazaki, T.; Ito, H.; Kamiyasu, K.; Kim, S.; Kawamura, M.;
Hamanaka, N. New orally active serine protease inhibitors. J. Med. Chem. 1995,
38, 2521–2523; (c) Watanabe, T.; Hayashi, K.; Yoshimatsu, S.; Sakai, K.;
Takeyama, S.; Takashima, K. Studies of hypolipidemic agents, 1: synthesis and
hypolipidemic activities of alkoxycinnamic acie derivatives. J. Med. Chem.
1980, 23, 50–59; (d) Das, B.; Banerjee, J.; Chowdhury, N.; Majhi, A.;
Mahender, G. Synthetic application of the Baylis–Hillman reaction: simple and
convenient synthesis of five important insect pheromones. Helv. Chim. Acta
2006, 89, 876–883.
6. (a) Liu, Y. K.; Li, J.; Zheng, H.; Xu, D. Q.; Xu, Z. Y.; Zhang, Y. M. An atom-
economical and environmentally benign preparation of unsymmetrical bis-allyl
ethers via dimerization of Baylis–Hillman adducts catalyzed by cesium
hydroxide monohydrate. Synlett 2005, 2999–3001; (b) Liu, Y. K.;
Xu, X. S.; Zheng, H.; Xu, D. Q.; Xu, Z. Y.; Zhang, Y. M. A facile and stereo-
selective synthesis of unsymmetrical diallylsulfides via indium-promoted
one-pot reaction of Baylis–Hillman acetates, sodium thiosulfate, and allyl

Baylis–Hillman Acetates
4397
bromide. Synlett 2006, 571–574; (c) Liu, Y. K.; Zheng, H.; Xu, D. Q.;
Xu, Z. Y.; Zhang, Y. M. Sm/I2-mediated selective cleavage of the S-S or
C-S bonds of sodium (Z)-allyl thiosulfates in aqueous media: selective
formation of di(Z-allyl) disulfides or (2E)-methyl cinnamic esters. Synlett
2006, 2492–2494.
7. Liu, Y. K.; Zhang, Y. M. Stereoselective synthesis of (2E)-cinnamanilides via
desulfonylation of (2E)-a-amido-a,b-unsaturated sulfones by samarium/glacial
acetic acid/ethanol system. Org. Prep. Proced. Int. 2001, 33, 372–375.
8. Selected other methods for preparation of 2-methyl alkanoates: (a) Nakamura, E.;
Aoki, S.; Sekiya, K.; Oshino, H.; Kuwajima, I. Carbon–carbon bond-forming
reactions of zinc homoenolate of esters: a novel three-carbon nucleophile with
general synthetic utility. J. Am. Chem. Soc. 1987, 109, 8056–8066; (b) Oi, S.;
Moro, M.; Ito, H.; Honma, Y.; Miyano, S.; Inoue, Y. Rhodium-catalyzed
conjugate addition of aryl- and alkenyl-stannanes to a,b-unsaturated carbonyl
compounds. Tetrahedron 2002, 58, 91–97; (c) Elinson, M. N.;
Fuducovich, S. K.; Dorofeev, A. S.; Vereshchagin, A. N.; Nikishin, G. I. Electro-
chemically induced Favorsky rearrangement of alkyl benzyl ketones. Russ. Chem.
Bull., Int. Ed. 2003, 52, 228–231.
9. Banik, B. K.; Venkatraman, M. S.; Banik, I.; Basa, M. K. Samarium-induced
reductive dimerization of methyl cinnamate: synthesis of 2,8-diaminochrysene.
Tetrahedron Lett. 2004, 45, 4737–4739.