AlCl3-catalyzed oxidation of alcohol

Article abstract of DOI:10.1016/j.tet.2010.09.035

The metalloid salt AlCl₃, applied as catalyst for the oxidation of alcohol was presented. In water media, variety of alcohols, including inactive aliphatic alcohols, could be converted into corresponding carbonyl compounds with excellent conversion and selectivity. Especially, this green reaction system also exemplifies advances toward the domino synthesis alkenes in good yields (>52%) and perfect purity (>99%), and the reaction gave preferentially the E-isomer. The obvious advantages of the present protocol include green reaction media, wide functional group tolerance, convenient product isolation, as well as grams reaction scale.

Full text of DOI:10.1016/j.tet.2010.09.035

Tetrahedron 66 (2010) 8641e8647
Contents lists available at ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
AlCl3-catalyzed oxidation of alcohol
*
Shang Wu, Hengchang Ma, Ziqiang Lei
Key Laboratory of Polymer Materials of Gansu Province, Key Laboratory of Eco-Environment-Related Polymer Materials Ministry of Education, College of Chemistry and Chemical
Engineering, Northwest Normal University, Lanzhou 730070, 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:
Received 29 June 2010
Received in revised form 8 September 2010
Accepted 10 September 2010
Available online 17 September 2010
The metalloid salt AlCl3, applied as catalyst for the oxidation of alcohol was presented. In water media,
variety of alcohols, including inactive aliphatic alcohols, could be converted into corresponding carbonyl
compounds with excellent conversion and selectivity. Especially, this green reaction system also ex-
emplifies advances toward the domino synthesis alkenes in good yields (>52%) and perfect purity
(>99%), and the reaction gave preferentially the E-isomer. The obvious advantages of the present pro-
tocol include green reaction media, wide functional group tolerance, convenient product isolation, as
well as grams reaction scale.
Keywords:
AlCl3
Alcohol oxidation
Metalloid element
Green chemistry
OxoneÒ
Ó 2010 Elsevier Ltd. All rights reserved.
Wittig reaction
1. Introduction
homogeneous metal catalysts16 often make practical and industrial
applications very difficult. Among them, the monomerically (or
Indubitably, oxidation of alcohols to their corresponding car-
bonyl compounds is one of the most important and challenging
transformations in the synthesis of fine chemicals and in-
termediates.1 Traditional methods always use large amounts of
transition-metal involved noxious oxidants, such as chromate and
permanganate,2 or non-green organic solvents,3 or require severe
reaction conditions.4
From an environmental and economic viewpoint, these pro-
cedures are discouraged for the reason that most of them suffer
from low atom efficiency5 and a large amount of waste products,6
leading to a severe environmental impact.7 Consequently, the ex-
tensive research interests focused on metal-catalyzed oxidation
systems, which prefer to use molecular oxygen as the terminal
oxidant since innocuous byproducts (H2O or H2O2) and high atom
economy.8,9 Transition-metal-catalyzed aerobic oxidation of alco-
hols has recently been reviewed,10 and these reviews outline sig-
nificant progress in the elaboration of homogeneous and/or
heterogeneous catalysts in general. However, for the most cases,
harmful organic solvents are always indispensable,11 such as N-
hydroxyphthalimide,12 diethyl azodicarboxylate,13 or nitrasonium
ions,14 and some ligands15 were required to accomplish the cata-
lytic cycle, as well as the catalyst separation and recycling of
highly) dispersed metal hydroxide species on the appropriate
supporters turned out to be a powerful heterogeneous catalyst for
the alcohol oxidation. For the representative work as example,
Al2O3 supported RuIVeOH catalyst.17 The noble-metal mediated
catalyst system demonstrated high turn over numbers (up to 980),
effective reusable property and wide functional group tolerance.
Even though the excellent catalytic performance, the limitations for
the adsorbed type catalyst system are obvious, such as catalyst
leaching, using of harmful solvent and more complicated synthesis
procedure.
We considered that the most preferable oxidation procedures
were that the oxidation reactions could be carried out in harmful-
ness solvent, the system would facilitate the separation of products
and even to prevent use of expensive catalyst. In the ongoing re-
search programs, we found that in water media, Lewis acid, AlCl3,
plays dominant role in the oxidation of alcohols in the presence of
OxoneÒ. This novel oxidation system could convert variety of alco-
hols to the corresponding carbonyl compounds. Evidently, AlCl3
hydrolyzed to oligomers [Al2(OH)nCl6ꢀn]m in aqueous phase firstly,
the hydrolyzed products have been regarded as water-soluble sup-
porter, the in situ formed AleOH was possibly applied as key in-
termediate for alcohol oxidation. Then our much attention were
attracted by the metalloid elements, such as Al, Si, involved sub-
stances because that the structurally common units AleOH, SieOH
are extensively exist in such materials, for example, polygorskite,
silica gel, and organosilicon. The screening experiments were tested,
* Corresponding author. Tel.: þ86 931 7971687; fax: þ86 931 7970359; e-mail
address: leizq@nwnu.edu.cn (Z. Lei).
0040-4020/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2010.09.035

8642
S. Wu et al. / Tetrahedron 66 (2010) 8641e8647
under specific conditions, polygorskite, silica gel, and organosilicon
demonstrated average to excellent catalytic behavior for the oxi-
dation of alcohols. Due tothe pioneering work, it is convinced that in
the transition-metal catalyst dominated field of alcohol oxidation,
the metalloid elements Al and Si will be important members in the
future. Our preliminary study disclosed that the efficient, environ-
mentally friendly, and inexpensive catalyst system, which renders
the oxidation of alcohols with advantages, such as green reaction
media, mild reaction conditions, wide functional group tolerance,
and convenient product isolation, as well as grams reaction scale. In
this communication, we report AlCl3 catalyzed oxidation of alcohols
in the presence of OxoneÒ in water media, furthermore, its appli-
cation in the domino synthesis of E-isomer alkene by alcohol oxi-
dation and Wittig reaction was also studied.
alcohols were oxidized to the corresponding acids with 100% con-
version at room temperature (entries 1e3). And the reaction also
provided good-to-excellent yields and purities (>99%) in the oxida-
tion of benzhydrol (1d) and substituted benzhydrols, such as
4-methylbenzhydrol (1e) and 4-chlorobenzhydrol (1f) (entries 4e6).
Cyclopentanol (1g) and cyclohexanol (1h) were transformed to the
respective ketone in high isolated yields and perfect purity (>99%)
(entries 7e8). Surprisingly, aliphatic alcohols, which are inactive in
most oxidation systems, were performed excellent activity. n-Hexyl
alcohol (1i), n-octanol (1j), and n-nonyl alcohol (1k) were all con-
verted to the corresponding acid with 100% conversion and selectiv-
ity, respectively (entries 9e11). However, with the increasing of the
number of carbon atoms, the conversions were reduced from 70% to
26%, even the temperature was elevated to 60 ꢁC (entries 12e14).
So as to apply the system to industrial research, several repre-
sentative oxidation alcohols were tested in more large scale
(Scheme 2). The typical experimental process as follows: OxoneÒ
(2.4 equiv) and the relevant AlCl3 were added to a solution of al-
cohol (10 g) in water. After stirring at rt/60 ꢁC for 4e8 h, the product
was precipitated on the reactor vessel with excellent yields (>93%),
especially, most crude product’s NMR purity was up to 99%.
2. Results and discussion
2.1. Catalytic activity in n-nonyl alcohol
In order to study the catalytic activity of AlCl3, the oxidation of
n-nonyl alcohol was determined as the model reaction to screen
the influence factors, such as the temperature, the amount of the
catalyst, and OxoneÒ, as well as the reaction time. The appropriate
condition is optimized as n-nonyl alcohol (0.1 mmol), OxoneÒ
(2.4 equiv), and the ratio of alcohol to AlCl3 is 0.1/0.27, stirred in
water at 60 ꢁC for 8 h, the reaction afforded nonanoic acid, which
was isolated in 93% yield and excellent purity (>99%). In a con-
trolled experiment, in the absence of AlCl3 or under entirely uni-
form pH conditions without AlCl3, it was found that the reaction did
not proceed even after a longer reaction time (Scheme 1). In the
presence of other aluminum salts and other metal chlorides, such
as Al(OH)3, Al2O3, MgCl2$6H2O, and SnCl2$2H2O, which gave poor
conversion (Fig. 1). Notably, under the specific reaction conditions,
only AlCl3 involved oxidation system gave product with excellent
conversion and selectivity.
2.3. The domino synthesis of alkene in the system
Wittig reaction has excelled as one of the most popular and
powerful methods to create carbonecarbon double bonds in syn-
thetic chemical methodology. The use of ylides in the presence of
aldehydes to provide access to alkenes with either high E- or Z-
geometrical selectivity has been researched extensively over many
years.18,19 In order to extend the application of our clean reaction
system, the domino synthesis of alkenes, started from oxidation
and then olefination, has been studied. Under the optimized con-
ditions, after adding ylides, the final product of alkene was obtained
only. The oxidation of in situ generated aldehyde was diminished
(Scheme 3). Then we broaded the scope of domino synthesis al-
Scheme 1. The controlled experiment.
kene, and the representative procedure carried out as follows. The
required amount of OxoneÒ (2.4 equiv), ylides (1.5 equiv), and the
relevant AlCl3 were added to a solution of the alcohol (2 mmol) in
water. Then, the mixture was stirred at rt for 2e4 h. The result
suggested that our catalysis system provided complete bias to
olefination compounds (Table 2).
We examined the scope of the aqueous Wittig reaction for the
synthesis of alkene. The results are depicted in Table 2. The Wittig
reaction in water is a straightforward protocol that works favorably
between yields and aromatic alcohols having electron donating or
electron withdrawing groups. All the products were isolated in
moderate to excellent yields and the reaction gave preferentially
the E-isomer. The presence of electron withdrawing groups in-
creased the reaction rates (entries 2e4), whereas electron-re-
leasing groups gave the corresponding product in lower yield
(entries 5e9).
Fig. 1. The oxidation of n-nonyl alcohol in the presence of other aluminum salts.
2.4. Discussion of the reaction mechanism
2.2. Oxidation of a series alcohols
Based on the literatures,17,20e22 we have proposed a plausible
mechanism for the alcohol oxidation (Scheme 4), that proceeds via
an aluminium alkoxide intermediate II, which was formed between
To evaluate the scope of Al-involved catalytic system, we in-
vestigated the oxidation of a number of alcohols (Table 1). Benzyl

S. Wu et al. / Tetrahedron 66 (2010) 8641e8647
8643
Table 1
Oxidation of a series of alcoholsa
Entry
1
Substrate
Product
T (ꢁC)
t (h)
Conv. (%)
100
Sele. (%)
83
Yieldb (%)
rt
4
80
77
2
3
4
rt
rt
rt
4
4
4
100
87
80
92
76
98
100
100
5
6
rt
rt
4
4
100
100
100
100
97
96
7
8
rt
rt
4
4
100
100
100
100
90
93
9
60
60
8
8
100
100
100
100
88
91
10
11
12
13
60
60
60
8
8
8
100
70
100
100
100
93
52
36
54
14
60
8
26
73
nr
a
Reaction condition: alcohol 0.10 mmol, AlCl3 2.7 equiv, OxoneÒ/alcohol¼2.4:1, water 3 mL. Percentage conversation and reaction selectivity were determined by GC
analysis.
b
Yield of isolated product.

8644
S. Wu et al. / Tetrahedron 66 (2010) 8641e8647
Scheme 2. Oxidation of representative alcohols in grams scale.[a]
3. Conclusions
In conclusion, we have developed a green, clean, and highly
active catalytic system for the oxidation of a wide variety of alco-
hols, including benzyl alcohols, benzhydrols, cyclic, and aliphatic
alcohols. Especially, this green reaction system also exemplifies
advances toward the domino synthesis alkene in good yields
(>52%) and perfect purity (>99%), and the reaction gave prefer-
entially the E-isomer. Remarkably, this new form of oxidation re-
action is interesting in keeping with the notion of green chemistry
due to non-use of heavy metals and halogenated solvents, less
waste reducts, high-yielding (even in large scale), mild conditions,
easy to work up (most do not require chromatography) and should
provide a mild oxidative alternative for organic chemists.
4. Experimental
4.1. General remarks
Scheme 3. The competitive reaction between oxidation and olefination.
OxoneÒ was obtained from commercial sources. All solvents
used were analytical grade and were used as received. All of the
alcohols used in the reaction were obtained from ABCR GmbH & Co.
KG. and used without further treatment. H218O was obtained from
Huayi Isotope Co. and used as received. The melting points of iso-
lated products were determined on a WRS-1A digital melting point
apparatus. All NMR spectra are recorded on MERCURY (400 MHz
for 1H NMR, 100 MHz for 13C NMR) spectrometers; chemical shifts
alcohol and hydrolyzed AlCl3 I, and then II undergoes b-hydrogen
elimination to produce the carbonyl compound and aluminium
hydride species III. As reported that in the presence of OxoneÒ, free
ion Clꢀ could be generated to the more effective oxidizing agent
Clþ,21 which possibly chloridize aluminium hydride species to the
intermediate AleCl IV, in the following step, hydrolyzation of AleCl
occurred and the hydrolysate AleOH regarded as catalytic species,
started the next catalytic cycle.
are expressed in parts per million (d units) relative to TMS signal as
an internal reference in CDCl3 or DMSO-d6. Gas chromatography
In order to determine the plausible mechanism, isotope-labeled
alcohols were performed in the presence of AlCl3/OxoneÒ/H2O
under N2 sphere (Scheme 5), GC/MS detector indicated that the
abundance of 16O in product was >97%. That is, the dehydration
process involving a selective cleavage of the CeO bond of the al-
cohol with concomitant formation of a new C]O bond, in the
product, the oxygen atoms transfer from Oxone or solvent. The
further study demonstrated that when the oxidation of isotope-
labeled alcohols was carried out in the solvent of H218O, the
abundance of 18O in product surprisingly increased to 90%. This
interesting finding verified that in the process of oxidation alcohol,
the exchange of oxygen atoms between alcohol and water was
taken placed. Another 10% amount of 16O labeled product probably
originates from the hydrolyzation of species IV with H216O.
(GC) analysis was performed on a Shimadezu GC-2010 equipped
with a 15 mꢂ0.53 mmꢂ1.5
mm RTX-1 capillary column and a oxy-
hydrogen flame detector. GC/MS analysis were carried out on
a trace HP GC6890/MS5973 equipped with a 25 mꢂ0.25 mm SE-54
column and
a Shimadzu GC-16A gas chromatograph with
a 3 mꢂ3 mm OV-17 column.
4.2. General procedure for the oxidation of alcohol
A typical reaction was carried out as follows: n-nonyl alcohol
(0.1 mmol), OxoneÒ (2.4 equiv), and AlCl3 (2.7 equiv) were dis-
solved in 3 mL of water. The mixture was stirred at 60 ꢁC for 8 h and
monitored by TLC. After completion, it was extracted with ethyl

S. Wu et al. / Tetrahedron 66 (2010) 8641e8647
8645
Table 2
The domino synthesis of alkenea
Entry
1
Substrate
Product
t (h)
Yieldb (%)
2
68
75
2
3
4
2
2
2
80
93
5
3
56
6
7
8
3
3
4
58
55
52
9
3
60
a
Reaction condition: the required amount of OxoneÒ (2.4 equiv), ylides (1.5 equiv), and the relevant AlCl3 were added to a solution of the alcohol (2 mmol) in water, room
temperature.
b
Yield of isolated product.
Scheme 4. The plausible reaction mechanism.

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S. Wu et al. / Tetrahedron 66 (2010) 8641e8647
Scheme 5. The oxidation of isotope-labeled alcohols.
acetate. The organic layer was dried and removed under reduced
pressure to give the desired crude product. Analytically pure
products were obtained after recrystallizing or column chroma-
tography using petroleum ether and ethyl acetate (10:1, v/v) as
eluent. Formation of products and consumption of substrates were
monitored by GC. The identity of products was determined either
by comparison with authentic samples using gas chromatography
or by NMR analysis. The conversion and product selectivity were
determined using GC analysis.
J¼8 Hz, 2H, AreH), 7.64e7.60 (t, J¼8 Hz, 1H, AreH), 7.50e7.46 (t,
J¼8 Hz, 2H, AreH); 13C NMR (100 MHz, CDCl3):
¼172.39, 133.81,
d
130.20, 129.30, 128.46.
4.6.1.2. 4-Chlorobenzyl acid (2b). White solid (0.263 g, 77%);
mp¼201e202 ꢁC; 1H NMR (400 MHz, DMSO-d6):
¼13.18 (s, 1H,
d
COOH), 7.96e7.94 (d, J¼8 Hz, 2H, AreH), 7.58e7.56 (d, J¼8 Hz, 2H,
AreH); 13C NMR (100 MHz, DMSO-d6):
129.59, 128.70.
d¼166.38, 137.76, 131.10,
4.3. General procedure of large scale for isolating products
4.6.1.3. 4-Nitrobenzyl acid (2c). Pale-yellow solid (0.2735 g,
76%); mp¼241e243 ꢁC; 1H NMR (400 MHz, DMSO-d6):
¼13.67 (s,
d
The required amount of OxoneÒ (2.4 equiv) and the relevant
AlCl3 were added to a solution of the alcohol (10 g) in water. Then,
the mixture was stirred at 60 ꢁC/rt for 4e8 h and monitored by TLC.
After completion, the suspension was filtrated and the solution was
extracted with ethyl acetate. The organic layer was removed under
reduced pressure to give the desired crude products. The solid and
crude products were washed by petroleum ether several times to
obtain the analytically pure products. Formation of products and
consumption of substrates were monitored by GC. The identity of
products was determined either by comparison with authentic
samples using gas chromatography or by NMR analysis. The con-
version and selectivity were determined using GC analysis.
1H, COOH), 8.34e8.32 (d, J¼8 Hz, 2H, AreH), 8.19e8.17 (d, J¼8 Hz,
2H, AreH); 13C NMR (100 MHz, DMSO-d6):
136.31, 130.64, 123.68.
d
¼165.73, 150.00,
4.6.1.4. Benzophenone (2d). White solid (0.3572 g, 98%);
mp¼46e48 ꢁC; 1H NMR (400 MHz, CDCl3):
¼7.81e7.80 (m, 4H,
d
AreH), 7.60e7.57 (m, 2H, AreH), 7.50e7.46 (m, 4H, AreH); 13C NMR
(100 MHz, CDCl3):
d¼196.67, 137.57, 132.36, 130.01, 128.23.
4.6.1.5. 4-Chlorobenzophenone (2e). White solid (0.42 g, 97%);
mp¼75e79 ꢁC; 1H NMR (400 MHz, CDCl3):
¼7.79e7.75 (m, 4H,
d
AreH), 7.62e7.58 (m, 1H, AreH), 7.51e7.46 (m, 4H, AreH); 13C NMR
(100 MHz, CDCl3):
129.91, 128.61, 128.38.
d
¼195.45, 138.88, 137.23, 135.86, 132.60, 131.43,
4.4. General procedure of the olefination products
The required amount of OxoneÒ (2.4 equiv), ylides (1.5 equiv),
and the relevant AlCl3 was added to a solution of the alcohol
(2 mmol) in water, and AlCl3 was added stepwise. Then, the mixture
was stirred at rt for 2e4 h, after completion, it was extracted with
ethyl acetate. The organic layer was dried and removed under re-
duced pressure to give the desired crude product. Analytically pure
products were obtained after column chromatography using pe-
troleum ether and ethyl acetate as eluent. The identity of products
was determined by NMR analysis.
4.6.1.6. 4-Methylbenzophenone (2f). White solid (0.3759 g,
96%); mp¼55e58 ꢁC; 1H NMR (400 MHz, CDCl3):
¼7.79e7.77 (d,
d
J¼8 Hz, 2H, AreH), 7.73e7.71 (d, J¼8 Hz, 2H, AreH), 7.59e7.55 (t,
J¼8 Hz, 1H, AreH), 7.49e7.45 (t, J¼8 Hz, 2H, AreH), 7.29e7.27 (t,
J¼8 Hz, 2H, AreH), 2.44 (s, 3H, CH3); 13C NMR (100 MHz, CDCl3):
d
¼196.43, 143.19, 137.93, 134.87, 132.11, 130.26, 129.88, 128.94,
128.16, 21.63.
4.6.1.7. Cyclopentanone (2g). Colorless liquid (0.152 g, 90%); 1H
NMR (400 MHz, CDCl3):
NMR (100 MHz, CDCl3):
d
¼1.88 (s, 4H, CH2), 1.71 (s, 4H, CH2); 13C
4.5. Preparation of 18O enriched benzyl alcohol
d¼219.57, 37.60, 22.59.
Na (0.05 g) was added to 0.75 mL 18O enriched water (98% H218O,
Huayi Isotope Co.) in a flask, and then 0.5 mL 1-chloromethyl
benzene was added into the flask. The mixture was heated to 95 ꢁC
and refluxed for 48 h with continuous stirring. The product was
purified by column chromatography and 0.2 g C6H5CH218OH was
obtained. The 18O enriched benzyl alcohol was examined by GC/MS,
and the abundance of C6H5CH218OH was 98%.
4.6.1.8. Nonanoic acid (2k). Colorless oil (0.162 g, 93%); 1H NMR
(400 MHz, CDCl3):
¼11.60 (s, 1H, COOH), 2.37e2.33 (t, J¼8 Hz, 2H,
d
CH2), 1.67e1.63 (t, J¼8 Hz, 2H, CH2), 1.30 (s, 10H, CH2), 0.90e0.86 (t,
J¼8 Hz, 3H, CH3); 13C NMR (100 MHz, CDCl3):
¼180.70, 34.13,
d
31.78, 29.19, 29.04, 24.63, 22.62, 14.04.
4.6.2. The NMR data for the olefination products 3a, 3c, 3oeu.
4.6.2.1. (E)-Ethyl cinnamate (3a). Pale-yellow oil (0.2441g, 68%); 1H
4.6. Analysis
NMR (400 MHz, CDCl3):
d
¼7.60e7.56 (d, J¼16 Hz, 1H, CH]),
7.41e7.39 (m, 2H, AreH), 7.27e7.26 (m, 3H, AreH), 6.35e6.31 (d,
J¼16 Hz, 1H, CH]), 4.18e4.13 (m, 2H, CH2), 1.24e1.21 (t, J¼12 Hz, 3H,
4.6.1. The NMR data for the oxidation products 2aeg, k.
4.6.1.1. Benzyl acid (2a). White solid (0.219 g, 80%); mp¼121e122 ꢁC;
CH3); 13C NMR (100 MHz, CDCl3):
128.69, 127.87, 118.09, 60.30, 14.16.
d¼166.76, 144.37, 134.27, 130.03,
1H NMR (400 MHz, CDCl3):
d
¼12.35 (s, 1H, COOH), 8.14e8.12 (d,

S. Wu et al. / Tetrahedron 66 (2010) 8641e8647
8647
4.6.2.2. (E)-Ethyl 3-(4-nitrophenyl)acrylate(3c). Pale-yellow solid
(0.3316g, 75%); 1H NMR (400 MHz, CDCl3):
CDCl3):
60.24, 21.24, 14.25.
d
¼167.01, 144.34, 140.45, 131.63, 129.43, 127.98, 117.18,
d¼8.22e8.20 (d, J¼8 Hz,
2H, AreH), 7.68e7.66 (d, J¼8 Hz, 2H, AreH), 7.03e7.00 (d, J¼12 Hz,
1H, CH]), 6.15e6.12 (d, J¼12 Hz, 1H, CH]), 4.20e4.15 (m, 2H, CH2),
1.26e1.23 (t, J¼12 Hz, 3H, CH3); 13C NMR (100 MHz, CDCl3):
Acknowledgements
d¼165.29, 141.56, 141.46, 140.48, 130.16, 128.58, 123.15, 60.71, 14.02.
This work was financially supported by National Natural Science
Foundation of China (No. 20674063 and 20774074) and Specialized
Research Fund for the Doctoral Program of Higher Education
(20050736001). We also thank Key Laboratory of Eco-Environ-
ment-Related Polymer Materials (Northwest Normal University),
Ministry of Education, for financial support.
4.6.2.3. (E)-Ethyl 3-(2, 4-dichlorophenyl)acrylate (3o). White
solid (0.3920g, 80%); 1H NMR (400 MHz, CDCl3):
d
¼8.03e7.99 (d,
J¼16 Hz, 1H, CH]), 7.56e7.54 (d, J¼8 Hz, 1H, AreH), 7.44 (s, 1H,
AreH), 7.28e7.26 (d, J¼8 Hz, 1H, AreH), 6.43e6.39 (d, J¼16 Hz, 1H,
CH]), 4.31e4.24 (m, 2H, CH2), 1.36e1.33 (t, J¼12 Hz, 3H, CH3); 13
C
NMR (100 MHz, CDCl3):
129.94, 128.30, 127.52, 121.31, 60.79, 14.28.
d
¼166.24, 139.11, 136.25, 135.45, 131.31,
References and notes
1. Hou, Z.; Theyssen, N.; Brinkmann, A.; Leitner, W. Angew. Chem., Int. Ed. 2005, 44,
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3. (a) Zhan, B. Z.; White, M. A.; Sham, T. K.; Pincock, J. A.; Doucet, R. J.; Rao, K. V. R.;
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Soc. 2005, 127, 18004e18005.
4. Enache, D. I.; Edwards, J. K.; Landon, P.; Solsona-Espriu, B.; Carley, A. F.; Herzing, A. A.;
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5. Mallat, T.; Baiker, A. Chem. Rev. 2004, 104, 3037e3058.
4.6.2.4. (E)-Ethyl 3-(2-chloro-4-nitro phenyl)acrylate (3p). White
solid (0.4751g, 93%); 1H NMR (400 MHz, CDCl3):
d¼8.385 (s, 1H,
AreH), 8.14e8.12 (d, J¼8 Hz, 1H, AreH), 7.57e7.55 (d, J¼8 Hz,
1H, AreH), 7.10e7.07 (d, J¼12 Hz, 1H, CH]), 6.24e6.21 (d, J¼12 Hz,
1H, CH]), 4.17e4.12 (m, 2H, CH2), 1.22e1.19 (t, J¼12 Hz, 3H, CH3);
13C NMR (100 MHz, CDCl3):
126.02, 124.34, 124.07, 122.50, 60.78, 14.22.
d
¼164.79,139.81,138.12,135.36,129.90,
6. Trost, B. M. Science 1991, 254, 1471e1477.
4.6.2.5. (E)-Ethyl 3-(4-hydroxyphenyl)acrylate (3q). White solid
7. (a) Metzger, J. O. Angew. Chem., Int. Ed.1998, 37, 2975e2978; (b) Eissen, M.; Metzger,
J. O.; Schmidt, E.; Schneidewind, U. Angew. Chem., Int. Ed. 2002, 41, 414e436.
8. (a) Sheldon, R. A. Pure Appl. Chem. 2000, 72, 1233e1246; (b) Itoh, A.; Hashimoto,
S.; Kuwabara, K.; Kodama, T.; Masaki, Y. Green Chem. 2005, 7, 830e832; (c)
Kuwabara, K.; Itoh, A. Synthesis 2006, 12, 1949e1952; (d) Sugai, T.; Itoh, A.
Tetrahedron Lett. 2007, 48, 2931e2934; (e) Sugai, T.; Itoh, A. Tetrahedron Lett.
2007, 48, 9096e9099; (f) Hirashima, S.; Itoh, A. Green Chem. 2007, 9, 318e320.
9. (a) Ng, Y. H.; Ikeda, S.; Harada, T.; Morita, Y.; Matsumura, M. Chem. Commun.
2008, 3181e3183; (b) Ten Brink, G. J.; Arends, I. W. C. E.; Sheldon, R. A. Adv.
Synth. Catal. 2002, 344, 355e369; (c) Ten Brink, G. J.; Arends, I. W. C. E.; Hoo-
genraad, M.; Verspui, G.; Sheldon, R. A. Adv. Synth. Catal. 2003, 345, 497e505;
(d) Ten Brink, G. J.; Arends, I. W. C. E.; Hoogenraad, M.; Verspui, G.; Sheldon, R.
A. Adv. Synth. Catal. 2003, 345, 1341e1352; (e) Marko, I. E.; Gautier, A.; Du-
meunier, R.; Doda, K.; Philippart, F.; Brown, S. M.; Urch, C. J. Angew. Chem., Int.
Ed. 2004, 43, 1588e1591; (f) Yamada, Y. M. A.; Arakawa, T.; Hocke, H.; Uozumi,
Y. Angew. Chem., Int. Ed. 2007, 46, 704e706; (g) Kantam, M. L.; Pal, U.; Sreedhar,
B.; Bhargava, S.; Iwasawa, Y.; Tada, M.; Choudary, B. M. Adv. Synth. Catal. 2008,
350, 1225e1229; (h) Qiu, S.; Wei, Y.; Liu, G. Chem.dEur. J. 2009, 15, 2751e2754;
(i) Mitsudome, T.; Noujima, A.; Mizugaki, T.; Jitsukawa, K.; Kaneda, K. Adv.
Synth. Catal. 2009, 351, 1890e1896.
(0.2150g, 56%); 1H NMR (400 MHz, CDCl3):
d
¼7.66e7.62 (d,
J¼16 Hz, 1H, CH]), 7.42e7.40 (d, J¼8 Hz, 2H, AreH), 6.88e6.86 (d,
J¼8 Hz, 2H, AreH), 6.31e6.27 (d, J¼16 Hz, 1H, CH]), 4.30e4.24 (m,
2H, CH2), 1.35e1.32 (t, J¼12 Hz, 3H, CH3); 13C NMR (100 MHz,
CDCl3):
14.26.
d¼168.12, 158.22, 144.92, 130.03, 126.80, 115.90, 60.69,
4.6.2.6. (E)-Ethyl 3-(4-(dimethylamino)phenyl)acrylate (3r). Pale-
yellow solid (0.2539g, 58%); 1H NMR (400 MHz, CDCl3):
d¼7.64e7.60
(d, J¼16 Hz, 1H, CH]), 7.42e7.40 (d, J¼8 Hz, 2H, AreH), 6.67e6.65 (d,
J¼8 Hz, 2H, AreH), 6.24e6.20 (d, J¼16 Hz, 1H, CH]), 4.26e4.21 (m,
2H, CH2), 3.01 (s, 6H, N(CH3)2), 1.34e1.31 (t, J¼12 Hz, 3H, CH3); 13C
NMR (100 MHz, CDCl3):
112.83, 112.03, 60.25, 40.35, 14.64.
d
¼168.10, 151.93, 145.34, 129.91, 122.51,
10. (a) Zhan, B. Z.; Thompson, A. Tetrahedron 2004, 60, 2917e2935; (b) Schultz, M.
J.; Sigman, M. S. Tetrahedron 2006, 62, 8227e8241; (c) Sigman, M. S.; Jensen, D.
R. Acc. Chem. Res. 2006, 39, 221e229.
11. (a) Velusamy, S.; Ahamed, M.; Punniyamurthy, T. Org. Lett. 2004, 6, 4821e4824;
(b) Velusamy, S.; Punniyamurthy, T. Org. Lett. 2004, 6, 217e219.
12. Iwahama, T.; Yosino, Y.; Keitoku, T.; Sakaguchi, S.; Ishii, Y. J. Org. Chem. 2000, 65,
6502e6507.
4.6.2.7. (E)-Ethyl 3-(4-methoxyphenyl)acrylate (3s). Colorless oil
(0.2262 g, 55%); 1H NMR (400 MHz, CDCl3):
d
¼7.66e7.62 (d,
J¼16 Hz, 1H, CH]), 7.48e7.46 (d, J¼8 Hz, 2H, AreH), 6.90e6.88 (d,
J¼8 Hz, 2H, AreH), 6.32e6.28 (d, J¼16 Hz, 1H, CH]), 4.27e4.22 (m,
2H, CH2), 3.83 (s, 3H, eOCH3), 1.34e1.31 (t, J¼12 Hz, 3H, CH3); 13C
13. Kogan, V.; Quintal, M. M.; Neumann, R. Org. Lett. 2005, 7, 2039e2042.
14. Jiang, N.; Ragauskas, A. J. Org. Lett. 2005, 7, 3689e3692.
NMR (100 MHz, CDCl3):
115.67, 114.26, 60.28, 55.37, 14.33.
d
¼167.30, 161.28, 144.23, 129.64, 127.15,
15. (a) Colladon, M.; Scarso, A.; Strukul, G. Green Chem. 2008, 10, 793e798;
(b) Dijksman, A.; Marino-GonzTlez, A.; Mairatai Payeras, A.; Arends, I. W. C. E.;
Sheldon, R. A. J. Am. Chem. Soc. 2001, 123, 6826e6833; (c) ten Brink, G.-J.; Arends,
I. W. C. E.; Sheldon, R. A. Science 2000, 287, 1636e1639; (d) Shapley, P. A.; Zhang,
N.; Allen, J. L.; Pool, D. H.; Liang, H. C. J. Am. Chem. Soc. 2000, 122, 1079e1091.
16. Guo, M. L.; Li, H. Z. Green Chem. 2007, 9, 421e423.
17. Yamaguchi, K.; Mizuno, N. Angew. Chem., Int. Ed. 2002, 41, 4538e4542.
18. (a) Maerckar, A. Org. React. 1965, 14, 270e490; (b) Maryanoff, B. E.; Reitz, A. B.
Chem. Rev. 1989, 89, 863e927; (c) Kolodiazhnyi, O. I. Phosphorus Ylides, Chem-
istry and Application in Organic Synthesis; Wiley-VCH: Weinheim, 1999.
19. (a) Goetz, H.; Nerdel, F.; Michaelis, H. Naturwissenschaften 1963, 50, 496e497;
(b) Vicente, J.; Chicote, M. T.; Fernandez-Baeza, J.; Fernandez-Baeza, A. New J.
Chem. 1994, 18, 263e268.
4.6.2.8. (E)-Ethyl 3-o-tolylacrylate (3t). White oil (0.1976 g,
52%); 1H NMR (400 MHz, CDCl3):
d
¼7.93e7.89 (d, J¼16 Hz, 1H,
CH]), 7.48e7.46 (d, J¼8 Hz, 2H, AreH), 7.20e7.11 (m, 3H, AreH),
6.31e6.27 (d, J¼16 Hz, 1H, CH]), 4.23e4.18 (m, 2H, CH2), 2.36 (s,
1H, AreCH3), 1.29e1.26 (t, J¼12 Hz, 3H, CH3); 13C NMR (100 MHz,
CDCl3):
119.15, 60.22, 19.54, 14.16.
d
¼166.77, 142.04, 137.37, 133.26, 130.58, 129.73, 126.22,
4.6.2.9. (E)-Ethyl 3-p-tolylacrylate (3u). White oil (0.228 g, 60%);
20. Travis, B. R.; Sivakumar, M.; Hollist, G. O.; Borhan, B. Org. Lett. 2003, 5,
1H NMR (400 MHz, CDCl3):
d
¼7.58e7.54 (d, J¼16 Hz, 1H, CH]),
1031e1034.
21. Zolfigol, M. A.; Bagherzadeh, M.; Mallakpour, S.; Chehardoli, G.; Kolvari, E.;
Choghamarani, A. G.; Koukabi, N. Catal. Commun. 2007, 8, 256e260.
22. van der Toorn, J. C.; Kemperman, G.; Sheldon, R. A.; Arends, I. W. C. E. J. Org.
Chem. 2009, 74, 3085e3089.
7.32e7.30 (d, J¼8 Hz, 2H, AreH), 7.08e7.06 (d, J¼8 Hz, 2H, AreH),
6.31e6.27 (d, J¼16 Hz, 1H, CH]), 4.18e4.13 (m, 2H, CH2), 2.26 (s,
3H, AreCH3), 1.25e1.21 (t, J¼16 Hz, 3H, CH3); 13C NMR (100 MHz,