Scope and Limitation of the Microwave-Assisted Catalytic Wittig Reaction

Article abstract of DOI:10.1002/ejoc.201500310

We have developed a microwave-assisted catalytic Wittig reaction. In this paper, we give full account of the scope and limitations of this reaction. A screening of various commercially available phosphine oxides as precatalysts revealed Bu₃P=O to be the most promising candidate. We tested 10 silanes for the in situ reduction of the phosphine oxide to generate Bu₃P as the actual catalyst. Different epoxides were tested as masked bases. In this context, cyclohexene oxide as well as butylene oxide proved to be suitable. The reaction could be carried out at 125 C, but higher yields and E/Z selectivities were obtained at 150 °C. Under the optimised reaction conditions, more than 40 examples for the conversion of various aldehydes into the corresponding alkenes are reported. The products were obtained in yields of up to 88 with high E selectivities. Moreover, we also describe the further screening of several chiral phosphines as catalysts for the microwave-assisted enantioselective catalytic Wittig reaction. The scope and limitations of the microwave-assisted catalytic Wittig reaction have been evaluated with respect to the catalyst, silane, solvent, reaction conditions, and substrates.

Full text of DOI:10.1002/ejoc.201500310

FULL PAPER
DOI: 10.1002/ejoc.201500310
Scope and Limitation of the Microwave-Assisted Catalytic Wittig Reaction
Marcel Hoffmann,[a] Sunetra Deshmukh,[a] and Thomas Werner*[a]
Keywords: Organocatalysis / Microwave chemistry / Olefination / Wittig reactions / Alkenes
We have developed a microwave-assisted catalytic Wittig re- could be carried out at 125 °C, but higher yields and E/Z
action. In this paper, we give full account of the scope and
limitations of this reaction. A screening of various commer-
cially available phosphine oxides as precatalysts revealed
Bu3P=O to be the most promising candidate. We tested 10
silanes for the in situ reduction of the phosphine oxide to
generate Bu3P as the actual catalyst. Different epoxides were
tested as masked bases. In this context, cyclohexene oxide
as well as butylene oxide proved to be suitable. The reaction
selectivities were obtained at 150 °C. Under the optimised
reaction conditions, more than 40 examples for the conver-
sion of various aldehydes into the corresponding alkenes are
reported. The products were obtained in yields of up to 88%
with high E selectivities. Moreover, we also describe the fur-
ther screening of several chiral phosphines as catalysts for
the microwave-assisted enantioselective catalytic Wittig re-
action.
indicates that a catalytic Wittig reaction can be more advan-
tageous than the stoichiometric variant in terms of cumu-
lative energy demand as well as greenhouse gas emis-
sions.[10a] Indeed, organoarsenic,[13] organotellurium,[14]
and organoantimony[15] compounds have been used for
catalytic Wittig-type reactions, probably due to the fact that
the corresponding oxides are considerably easier to reduce
than phosphine oxides.[16]
The classic Wittig reaction occurs between a carbonyl
compound, e.g., an aldehyde, and a phosphonium ylide to
give the corresponding alkene and stoichiometric amounts
of phosphine oxide as the by-product. The ylide is usually
prepared before the olefination by alkylation of a suitable
phosphine and subsequent deprotonation, which requires
stoichiometric amounts of a suitable base.[9] A catalytic cy-
cle would be based on the in situ reduction of the phosphine
oxide by-product and recycling of the resulting phosphine
as the catalyst. In 2009, O’Brien et al. reported the first
catalytic Wittig reaction (CWR, in phosphine) and sub-
sequently developed this approach further.[17]
For the chemoselective reduction of phosphine oxides, a
stoichiometric amount of a reductant is needed, which must
be carefully chosen to prevent possible side-reactions with
either the substrates or the desired product. In this context,
strong reductants like LiAlH4,[18] borohydrides,[19] or
DIBALH (diisobutylaluminium hydride),[20] which are
known to reduce phosphine oxides, are unsuitable. Silanes
are the reductants of choice, and they fulfill the require-
ments under various reaction conditions.[21] The reduction
strategy has also been applied by other groups to the Appel,
aza-Wittig, and Staudinger reactions.[22] Due to our interest
in the synthesis and application of phosphorus-based or-
ganocatalysts, we recently turned our attention to this very
exciting field.[23]
Introduction
Carbon–carbon double bonds are ubiquitous structural
elements in organic and natural product chemistry.[1] Nu-
merous methods for their preparation have been devel-
oped.[2] Of these, especially carbonyl olefinations,[3] e.g., the
Wittig reaction,[4] Peterson olefination,[5] or the Julia–Koci-
enski reaction,[6] as well as their numerous modifications,
give versatile access to alkenes. Since its discovery in 1953
by Wittig and Geissler, the Wittig reaction has become the
most recognised method for the chemo- and regioselective
olefination of carbonyl groups.[4] This reaction has been ex-
tensively studied and used in synthesis,[7] even on industrial
scale,[8] and a variety of reagents and modifications have
emerged.[9] However, the formation of stoichiometric
amounts of phosphine oxides represents the major disad-
vantage of the classic Wittig reaction, as it hampers atom
economy and product purification.[10] To overcome these
purification problems and to recycle the phosphine oxide
by-product, many approaches on a laboratory scale as well
as an industrial scale have been reported.[11] Nevertheless,
the inert phosphine oxides are often discarded as waste
products, as their reduction requires harsh reaction condi-
tions or the use of highly toxic phosgene.[12]
An alternative strategy involving the in situ reduction of
the phosphine oxide e.g., using silanes as reducing agents,
might be economically and ecologically beneficial. A re-
cently published life-cycle assessment by Huijbregts et al.
[a] Leibniz-Institut für Katalyse e.V. an der Universität Rostock,
Albert-Einstein-Straße 29a, 18059 Rostock, Germany
E-mail: Thomas.Werner@catalysis.de
http://www.catalysis.de/
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejoc.201500310.
4532
© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2015, 4532–4543

The Microwave-Assisted Catalytic Wittig Reaction
Table 1. Effect of selected reaction parameters.[a]
Results and Discussion
In this paper, we describe the impact of various reaction
parameters as well as the influence of the silane and masked
bases on the outcome of the reaction under microwave di-
electric heating (MWI). We have significantly extended the
substrate scope of the reaction. Based on our recently re-
ported protocol,[23d] we chose the reaction of benzaldehyde
(1a) and methyl bromoacetate (2a) to form methyl phenyl
propenoate (3a) as model reaction (Scheme 1).
Scheme 1. Model reaction for the reaction optimisation.
Initially, we screened several phosphine oxides as well as
Ph3P as potential (pre)catalysts (Table 1). Et3P=O gave the
desired product in only 5% yield (Table 1, entry 1). How-
ever, in the presence of Bu3P=O, a promising 56% yield was
achieved (Table 1, entry 2). Other (pre)catalysts proved to
be less efficient (Table 1, entries 3–7). In the absence of any
phosphine or phosphine oxide, no reaction was observed,
and in the presence of Bu3P=O but using conventional heat-
ing only a 30% yield could be obtained (Table 1, entries 8
and 9). This demonstrates the positive effect of microwave
dielectric heating. 1-Butanol and ethylene carbonate (EC)
proved to be unsuitable solvents in the model reaction
[a] Screening reactions were carried out on a 1.5 mmol scale.
R3P=O (10 mol-%), benzaldehyde (1a; 1.0 equiv.), methyl bromo-
(Table 1, entries 10 and 11). The best result was achieved acetate (2a; 1.2 equiv.), PhSiH3 (2.0 equiv.), butylene oxide
using dioxane as solvent (Table 1, entry 12). Decreasing the
reaction temperature from 150 °C to 125 °C led to a signifi-
cant decrease in yield (Table 1, entries 2 and 12). Com-
phosphine oxide was used as a mixture of diastereoisomers (58:42
(2.0 equiv.), solvent (0.75 mL), MWI 150 °C. [b] Yields and E/Z ra-
tios were determined by GC with n-hexadecane as internal stan-
dard, and reactions were performed in duplicate. [c] 125 °C. [d] The
monly observed by-products in the reaction mixture were
benzyl alcohol, originating from the reduction of 1a, and
methyl acetate, derived from the dehalogenation of 2a.
We then tested various silanes as potential reducing
agents for the in situ (re)generation of the phosphine cata-
lyst (Table 2). In the phenylsilane series, PhSiH3 proved to
be the most efficient reducing agent (Table 2, entries 1–3).
In the presence of 10 mol-% Bu3P=O, the desired product
was obtained in 56% yield. This could be improved to 66%
yield by using 15 mol-% of the precatalyst. With lower
amounts of Bu3P=O, the yield decreased to 51%. The use
of aliphatic silanes such as Et3SiH, tBu2SiH2, and
nHexSiH3 as reducing agents generally gave poor yields of
the alkene of up to 9% (Table 2, entries 4–6). Similar results
were obtained with alkoxy silanes (Table 2, entries 7–9).
The readily available polymethylhydrosiloxane (PMHS) was
potentially a useful reducing agent. Recently, Kegelvich et
al. reported the reduction of phosphine oxides using PMHS
under microwave as well as thermal conditions.[24] Unfortu-
nately, PMHS proved to be inefficient as a reducing agent
in the catalytic Wittig reaction under our conditions, and
dr). [e] Conventional heating.
Table 2. Screening of silanes as reducing agents.[a]
Entry
Silane
Yield 3a [%][b]
E/Z[b]
1
2
3
Ph3SiH
Ph2SiH2
PhSiH3
0
–
33
88:12
86:14
–
56 (66,[c] 51[d]
)
4
5
6
7
8
9
10
Et3SiH
0
0
5
11
tBu2SiH2
nHexSiH3
(MeO)3SiH
(EtO)3SiH
(EtO)2MeSiH
PMHS
–
86:14
83:17
76:24
–
5
0
9 (11)[e]
85:15
[a] Screening reactions were carried out on a 1.5 mmol scale.
Bu3P=O (10 mol-%), benzaldehyde (1a; 1.0 equiv.), methyl bromo-
acetate (2a; 1.2 equiv.), silane (2.0 equiv.), butylene oxide
(2.0 equiv.), MWI 150 °C, 1 h. [b] Yields and E/Z ratios were deter-
mined by GC with n-hexadecane as internal standard, and reac-
tions were performed in duplicate. [c] 15 mol-% Bu3P. [d] 5 mol-%.
[e] 3 h.
the desired products were formed in low yields of up to role of the epoxide as a masked base is shown in Scheme 2.
11% (Table 2, entry 10).
The nucleophilic ring opening mediated by halogens is well
Finally, we studied the possibility of using different epox- recognised.[25] In our case, the bromide of the in situ formed
ides as masked bases for the in situ yilde formation. The phosphonium salt might act as the nucleophile. This would
Eur. J. Org. Chem. 2015, 4532–4543
© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
4533

M. Hoffmann, S. Deshmukh, T. Werner
FULL PAPER
liberate an alcoholate, which, in turn, could act as a base methoxy-substituted benzaldhydes 1i–1k gave the desired
to deprotonate the phosphonium salt and ultimately form products (i.e., 3e–3k) in moderate to good yields (Table 4,
the desired ylide. The corresponding halohydrin, formed in entries 9–19). The reactions of substrates bearing electron-
situ as a by-product, was detected by GC–MS analysis of withdrawing groups (i.e., 1l–1n) gave the corresponding ole-
the reaction mixture.
fination products in yields between 60 and 74% (Table 4,
entries 20–23). The reaction was highly E selective for meta-
and para-substituted substrates, while the selectivity for the
corresponding ortho-substituted derivatives was slightly
lower (e.g., compare Table 4, entry 20 with entries 22 and
23).
Table 4. Substrate scope and limitations for the reaction of aryl
aldehydes 1a–1n in the microwave-assisted catalytic Wittig reac-
tion.[a]
Scheme 2. Ylide formation using epoxides as masked bases.
Under the screening conditions, epoxides generally
proved to be suitable masked bases (Table 3). Propylene ox-
ide, butylene oxide, styrene oxide, and cyclohexene oxide all
gave the desired product (i.e., 3a) in moderate yields
(Table 3, entries 1–4). The best results were obtained with
butylene and cyclohexene oxides. Notably, in the presence
of sodium carbonate or potassium carbonate, no reaction
was observed (Table 3, entries 5 and 6).
Entry
Ar
Bu3P=O Product
[mol-%]
Yield
[%][b]
E/Z[c]
Table 3. Effect of various epoxides as masked bases.[a]
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Ph
1a
1b
1c
1d
1e
10
15
10
15
10
15
10
15
10
15
15
15
15
10
15
10
15
10
15
15
10
15
15
3a
3b
3c
3d
3e
69[d]
75
75
75
70
71
68[d]
78
63[c]
67
60
60
60
49
65
76
75
57
56
60
74
69
65
97:3
96:4
94:6
90:10
96:4
90:10
94:6
94:6
97:3
94:4
88:12
90:10
97:3
85:15
87:13
92:8
90:10
94:6
95:5
2-naphthyl
1-naphthyl
p-PhC6H4
p-tBuC6H4
o-MeC6H4
m-MeC6H4
p-MeC6H4
o-MeOC6H4
1f
1g
1h
1i
3f
3g
3h
3i
m-MeOC6H4
p-MeOC6H4
1j
1k
1l
3ja
3k
o-(CO2Me)C6H4
m-(CO2Me)C6H4 1m
3l
3m
77:23
93:7
95:5
[a] Screening reactions were carried out on a 1.5 mmol scale.
Bu3P=O (10 mol-%), benzaldehyde (1a; 1.0 equiv.), methyl bromo-
acetate (2a; 1.2 equiv.), PhSiH3 (2.0 equiv.), epoxide (2.0 equiv.), di-
oxane (0.75 mL), 150 °C. [b] Yields and E/Z ratios were determined
by GC with n-hexadecane as internal standard, and reactions were
performed in duplicate.
p-(CO2Me)C6H4 1n
3n
92:8
[a] Reaction conditions: Bu3P=O (10 or 15 mol-%), aldehyde 3
(2.0 m in dioxane; 1.0 equiv.), 2a (1.2 equiv.), PhSiH3 (1.5 equiv.),
butylene oxide (2.0 equiv.), MWI 150 °C, 2 h. [b] Isolated yields.
1
[c] E/Z ratio was determined by H NMR spectroscopy. [d] 3 h.
Having established standard reaction conditions, we went
We than turned our attention to the reactions of halogen-
on to investigate the substrate scope and limitations of the functionalised aryl derivatives 1o–1u (Table 5). Unfortu-
reaction. We started our study with aromatic aldehydes 1 nately, in all cases only moderate yields were obtained for
bearing electron-donating or electron-withdrawing groups the reaction with 2a (Table 5, entries 1–7). It should be
in the reaction with methyl bromoacetate (2a) to give the mentioned that for 1o–1t, significant amounts of methyl
corresponding alkenes (i.e., 3a–3n) (Table 4). The reactions cinnamate (3a) up to 20% were observed. This product
were carried out in the presence of 10 or 15 mol-% Bu3P=O might be formed from dehalogenation of either the sub-
as the precatalyst, and slightly better results were usually strate or the product. However, dehalogenation reactions of
achieved with the higher loading. Good yields of up to 78% organic halides using PhSiH3 usually require radical initia-
were achieved for the reactions of benzaldehyde (1a), naph- tors and proceed by radical mechanisms.[26]
thyl derivatives 1b and 1c, and substrate 1d (Table 4, en-
The reactions of heteroaromatic substrates 1v–1z with
tries 1–8). Alkyl-substituted benzaldehydes 1e–1h and methyl bromoacetate (2a) in the presence of Bu3P=O
4534
www.eurjoc.org
© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2015, 4532–4543

The Microwave-Assisted Catalytic Wittig Reaction
Table 5. Substrate scope and limitations for the reactions of
Table 6. Substrate scope and limitations for the reaction of ali-
phatic aldehydes 4 in the microwave-assisted catalytic Wittig reac-
tion.[a]
1o–1u.[a]
Entry
Ar
Product
Yield [%][b]
E/Z[c]
1
2
3
4
5
6
7
p-FC6H4 (1o)
o-ClC6H4 (1p)
m-ClC6H4 (1q)
p-ClC6H4 (1r)
m-BrC6H4 (1s)
p-BrC6H4 (1t)
o-(CF3)C6H4 (1u)
3o
3p
3q
3r
3s
3t
52[d,e]
52[e]
52[d]
50
99:1
96:4
97:3
95:5
99:1
98:2
73:27
53[e]
61
3u
54
[a] Reaction conditions: Bu3P=O (15 mol-%), aldehyde 3 (2.0 m in
dioxane; 1.0 equiv.), 2a (1.2 equiv.), PhSiH3 (1.5 equiv.), butylene
oxide (2.0 equiv.), MWI 150 °C, 2 h. [b] Isolated yields. [c] E/Z ratio
was determined by 1H NMR spectroscopy. [d] 3 h. [e] Yield was
1
determined by H NMR spectroscopy with mesitylene as internal
standard.
(15 mol-%) in the microwave at 150 °C for 2 h gave the cor-
responding products (i.e., 3v–3x) in yields of 36–58%
(Scheme 3). The reactions of 3y and 3z gave complex mix-
tures, and only traces of the desired products (i.e., 3y and
3z) could be detected.
Scheme 3. Reaction of heteroaromatic substrates in the microwave-
assisted catalytic Wittig reaciton. Reaction conditions: Bu3P=O
[a] Reaction conditions: Bu3P=O (10 or 15 mol-%), aldehyde 3
(2.0 m in dioxane; 1.0 equiv.), 2a (1.2 equiv.), PhSiH3 (1.5 equiv.),
butylene oxide (2.0 equiv.), MWI 150 °C, 2 h. [b] Isolated yields.
[c] E/Z ratio was determined by 1H NMR spectroscopy. [d] 1 h.
[e] 10 mol-%. [f] Yield was determined by 1H NMR spectroscopy
with mesitylene as internal standard, yield of the double bond iso-
mer in parentheses.
(15 mol-%), aldehyde
3 (2.0 m in dioxane; 1.0 equiv.), 2a
(1.2 equiv.), PhSiH3 (1.5 equiv.), butylene oxide (2.0 equiv.), MWI
150 °C, 2 h. [a] Determined by 1H NMR spectroscopy with mesity-
lene as internal standard.
Finally, we evaluated the olefination of aliphatic alde-
hydes 4 with 2a (Table 6). Again, the reaction proceeded
with a high E selectivity in all cases. The desired products
(i.e., 5a–5e) were obtained in moderate to good yields
(Table 6, entries 1–7). Surprisingly, furan derivative 5f could
even be obtained in 78% yield (Table 6, entry 8).
Products 5g and 5h were obtained as mixtures of double-
bond isomers that could not be separated by column
chromatography. We assume that a Michael addition and
subsequent deprotonation, elimination sequence led to the
corresponding double bond isomers, e.g., 7 (Scheme 4).
Scheme 4. Possible reaction sequence for the observed double bond
isomerisation.
contrast, no product formation was observed in the pres-
We turned our attention to alternative organohalides 2 as ence of 2f. When the sterically more demanding methyl 2-
substrates in reaction with anisaldehyde 1j (Table 7). When bromopropionate (2g) was used instead of 2a, 3jc was ob-
methyl chloroacetate (2b) was used instead of 2a, the yield tained in 53% yield (Table 7, entry 7). The reactions of 1j
dropped from 76 to 68% (Table 7, entries 1 and 2). Iodide with benzyl chlorides and bromides bearing electron-with-
derivative 2c gave the desired product (i.e., 3ja) in a con- drawing groups (i.e., 2h–2l) were also possible. However, the
siderably lower yield (Table 7, entry 3). In these reactions, corresponding products were obtained only in low to mod-
significant amounts of the dehalogenated by-product erate yields (Table 7, entries 8–12). Usually, the correspond-
methyl acetate were observed. The reaction of α-chloro- ing dehalogenated benzyl derivatives were observed in the
acetonitrile (2d) gave the desired product (i.e., 3jb) in just GC–MS traces of the reaction mixtures.
53% yield, whereas the bromo derivative (i.e., 2e) led to 3jb
At this point, the high complexity of the reaction mixture
in a very good yield of 88% (Table 7, entries 4 and 5). In should be emphasised. The catalytic Wittig reaction in-
Eur. J. Org. Chem. 2015, 4532–4543
© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
4535

M. Hoffmann, S. Deshmukh, T. Werner
FULL PAPER
Table 7. Substrate scope and limitations for the reactions of anisal- The key step to close the catalytic cycle is the subsequent
dehyde 1j with organohalides 2 in the microwave-assisted catalytic
reduction of this species to the phosphine. Assuming the
last step occurs chemoselectively and under full conversion,
Wittig reaction.[a] EWG = electron-withdrawing group.
step one (alkylation), step two (deprotonation), and the fi-
nal olefination step have to proceed in Ն90% yield to ob-
tain the desired product (i.e., 3) in yields Ͼ70%. Even to
obtain 3 in moderate yields of Ͼ50%, those steps have to
proceed in an average of 80% yield.
Recently, we reported the first enantioselective catalytic
Wittig reaction.[23e] Finally in this paper, we describe the
microwave-assisted variant of this reaction. In this context,
we examined the desymmetrisation of prochiral diketone 8
to give bicyclic olefin 9 in the presence of chiral phosphines
10–15 (Scheme 6). The reaction was carried out in the pres-
ence of 5 mol-% of the catalysts under microwave dielectric
heating. The results of the screening are shown in Table 8.
[a] Reaction conditions: Bu3P=O (15 mol-%), aldehyde 3 (2.0 m in
dioxane; 1.0 equiv.), 2 (1.2 equiv.), PhSiH3 (1.5 equiv.), butylene ox-
ide (2.0 equiv.), MWI 150 °C, 2 h. [b] Isolated yields are given.
1
[c] E/Z ratio determined by H NMR spectroscopy. [d] 10 mol-%.
volves four steps that must occur simultaneously in a single
reaction vessel (Scheme 5). The first step is the alkylation
of the phosphine to give the corresponding phosphonium
salt. Subsequent deprotonation gives rise to the ylide. Ole-
fination of the aldehyde (i.e., 1) gives the desired product
(i.e., 2) and produces the phosphine oxide as a by-product.
Scheme 6. Desymmetrisation of prochiral ketone 8 in the catalytic
Wittig reaction (CWR) under microwave dielectric heating using
chiral phosphine catalysts. Reaction conditions: chiral phosphine
10–15 (5 mol-%), substrate 8 (1 mmol), PhSiH3 (1.5 equiv.), 1,2-
butylene oxide (2.0 equiv.), 1,4-dioxane (0.5 mL), MWI 150 °C
(180 W), 2 h.
Table 8. Screening of chiral catalysts 8–13 for the enantioselective
catalytic Wittig reaction.[a]
Entry
Cat.
Yield [%]
ee [%][b]
er (R/S)[b]
1
2
3
4
5
6
10
11
12
13
14
15
Ͻ20[d]
Ͻ20[d]
39[c]
10
20
62
32
32
54
55:45
60:40
81:19
68:32
34:66
23:77
63[b]
Ͻ5[d]
Ͻ20[d]
[a] Reaction conditions: chiral phosphine 10–15 (5 mol-%), sub-
strate (1 mmol), PhSiH3 (1.5 equiv.), 1,2-butylene oxide
8
(2.0 equiv.), 1,4-dioxane (0.5 mL), MWI 150 °C, 2 h. [b] The ee and
er values were determined by chiral GC–MS. [c] Isolated yield after
column chromatography. [d] The yields were determined by 1H
NMR spectroscopic analysis of the reaction mixture with mesit-
ylene as internal standard.
Scheme 5. The four steps of the catalytic Wittig reaction.
4536
www.eurjoc.org
© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2015, 4532–4543

The Microwave-Assisted Catalytic Wittig Reaction
280 mg, 1.83 mmol), Bu3P=O (60 mg, 0.27 mmol, 15 mol-%),
PhSiH3 (248 mg, 2.29 mmol), and 1,2-epoxybutane (220 mg,
3.05 mmol) in dioxane (1 mL) were converted for 3 h. Purification
(SiO2, CH/EtOAc, 20:1) gave 3a (186 mg, 75%, E/Z = 97:3) as a
(R,R)-DIPAMP {10; 1,2-bis[(2-methoxyphenyl)(phenyl-
phosphino)]ethane} and (R,R)-DIOP [11; O-isopropylid-
ene-2,3-dihydroxy-1,4-bis(diphenylphosphino)butane] gave
the desired product (i.e., 9) in yields of Ͻ20%, and with
enantioselectivities of 10 and 20%, respectively (Table 8, en-
tries 1 and 2). Nevertheless, a moderate enantiomeric excess
could be obtained in the presence of (S,S)-Me-DuPhos [12;
1,2-bis(2,5-dimethylphospholano)benzene; 5 mol-%], which
gave an ee of 62% and an isolated yield of 39% (Table 8,
entry 3). The use of (R,R)-Me-BPE (13; 1,2-bis(2,5-dimeth-
ylphospholano)ethane) gave the desired product (i.e., 9) in
63% yield with an enantiomeric excess of 32% (Table 8, en-
try 4). This result indicates that both good yields and selec-
tivities are generally possible. The use of catalysts 14 and
15, both of which have a phospholane structure like 12 and
13, gave comparable ee’s but low yields.
1
colorless oil. H NMR (300 MHz, CDCl3): δ = 3.82 (s, 3 H, CH3),
6.46 (d, J = 16.0 Hz, 1 H, CH), 7.38–7.43 (m, 3 H, ArH), 7.51–
7.56 (m, 2 H, ArH), 7.72 (d, J = 16.0 Hz, 1 H, CH) ppm. 13C NMR
(75 MHz, CDCl3): δ = 51.56 (CH3), 117.66 (CH), 127.95 (2 CH),
128.76 (2 CH), 130.17 (CH), 134.23 (C), 144.73 (CH), 167.27
(C=O) ppm.
Methyl (E)-3-(2-Naphthyl)propenoate (3b):[28] According to the GP,
2-naphthaldehyde (1b; 239 mg, 1.53 mmol), methyl bromoacetate
(2a; 281 mg, 1.84 mmol), Bu3P=O (50 mg, 0.23 mmol, 15 mol-%),
PhSiH3 (248 mg, 2.30 mmol), and 1,2-epoxybutane (221 mg,
3.06 mmol) in dioxane (0.8 mL) were converted for 2 h. Purification
(SiO2, CH/EtOAc, 20:1) gave 3b (242 mg, 75%, E/Z = 90:10) as a
colorless solid. 1H NMR (300 MHz, CDCl3): δ = 3.85 (s, 3 H,
CH3), 6.57 (d, J = 16.0 Hz, 1 H, CH), 7.48–7.54 (m, 2 H), 7.66–
7.70 (m, 1 H), 7.80–7.91 (m, 4 H), 7.93–7.97 (m, 1 H) ppm. 13C
NMR (75 MHz, CDCl3): δ = 51.52 (CH3), 117.71 (CH), 123.25
(CH), 126.50 (CH), 127.04 (CH), 127.59 (CH), 128.39 (CH), 128.48
(CH), 129.80 (CH), 131.65 (C), 133.06 (C), 134.03 (C), 144.70
(CH), 167.27 (C=O) ppm.
Conclusions
We have evaluated the scope and limitations of the mi-
crowave-assisted catalytic Wittig reaction. As well as screen-
ing various readily available (pre)catalysts, we could estab-
lish that in general epoxides are suitable masked bases for
this reaction. Under the optimised reaction conditions,
moderate to good isolated yields and excellent E/Z selectivi-
ties for aromatic, heteroaromatic, and aliphatic olefins were
achieved. We investigated the influence of the catalyst load-
ing for a variety of substrates. Furthermore, the scope with
respect to the halide component was evaluated. 2-Bromo-
acetonitrile proved to be particularly suitable, giving the de-
sired product in 88% yield. We have presented a putative
reaction sequence that demonstrates the high overall effi-
ciency of the process that is necessary to achieve reasonable
yields. Moreover, we have also described further studies of
our stereoselective catalytic Wittig reaction in terms of an
intramolecular desymmetrisation using chiral bis-phos-
Methyl (E)-3-(1-Naphthyl)propenoate (3c):[28a,29] According to the
GP, 1-naphthaldehyde (1c; 153 mg, 0.980 mmol), methyl bromo-
acetate (2a; 181 mg, 1.18 mmol), Bu3P=O (32 mg, 0.15 mmol,
15 mol-%), PhSiH3 (159 mg, 1.47 mmol), and 1,2-epoxybutane
(141 mg, 1.96 mmol) in dioxane (0.5 mL) were converted for 2 h.
Purification (SiO2, CH/EtOAc, 20:1) gave 3c (147 mg, 71%, E/Z =
1
90:10) as a yellowish oil. H NMR (300 MHz, CDCl3): δ = 3.88 (s,
3 H, CH3), 6.56 (d, J = 15.8 Hz, 1 H, CH), 7.48–7.66 (m, 3 H,
ArH), 7.75–7.78 (m, 1 H, ArH), 7.85–7.93 (m, 2 H, ArH), 8.22 (m,
1 H, ArH), 8.56 (d, J = 15.8 Hz, 1 H, CH) ppm. 13C NMR
(75 MHz, CDCl3): δ = 51.55 (CH3), 120.16 (CH), 123.12 (CH),
124.78 (CH), 125.23 (CH), 126.01 (CH), 126.66 (CH), 128.52 (CH),
130.35 (CH), 131.18 (C), 131.43 (C), 133.45 (C), 141.59 (CH),
167.06 (C=O) ppm.
Methyl (E)-3-[(1,1Ј-Biphenyl)-4-yl]acrylate (3d):[28a] According to
the GP, 4-phenylbenzaldehyde (1d; 239 mg, 1.31 mmol), methyl
phines to give an enantiomerically enriched alkene with an bromoacetate (2a; 240 mg, 1.57 mmol), Bu3P=O (43 mg,
0.20 mmol, 15 mol-%), PhSiH3 (213 mg, 1.97 mmol), and 1,2-ep-
oxybutane (189 mg, 2.62 mmol) in dioxane (0.7 mL) were con-
verted for 2 h. Purification (SiO2, CH/EtOAc, 20:1) gave 3d
(243 mg, 78%, E/Z = 94:6) as a colorless solid. 1H NMR
(300 MHz, CDCl3): δ = 3.84 (s, 3 H, CH3), 6.49 (d, J = 16.0 Hz, 1
H, CH), 7.36–7.42 (m, 1 H, ArH), 7.44–7.50 (m, 2 H, ArH), 7.59–
7.66 (m, 6 H, ArH), 7.75 (d, J = 16.0 Hz, 1 H, CH) ppm. 13C NMR
(75 MHz, CDCl3): δ = 51.64 (CH3), 117.55 (CH), 126.95 (2 CH),
127.44 (2 CH), 127.78 (CH), 128.51 (2 CH), 128.83 (2 CH), 133.24
(C), 140.03 (C), 142.96 (C), 144.32 (CH), 167.38 (C=O) ppm.
er of 81:19.
Experimental Section
General Procedure (GP) for the Microwave-Assisted Catalytic Wit-
tig Reaction: Bu3P=O (10–15 mol-%), the aldehyde (2 m in 1,4-diox-
ane; 1.5 mmol, 1.0 equiv.), the organohalide (1.8 mmol, 1.2 equiv.),
PhSiH3 (2.3 mmol, 1.5 equiv.), and 1,2-epoxybutane (3.0 mmol,
2.0 equiv.) were put into a microwave vial (10 mL) equipped with
a stirrer bar. The vial was then purged with argon and sealed with
a septum, and the reaction mixture was heated by microwave irradi-
ation (MWI) at 150 °C for 1–3 h (150 W). The mixture was then
cooled to 23 °C, and dioxane (10 mL) and satd. aq. NH4F solution
(3 mL) were added. The mixture was then stirred at 23 °C for a
further 16 h. The mixture was diluted with H2O (25 mL), and the
aqueous layer was extracted with Et2O (3ϫ 10 mL). The combined
organic layers were dried with MgSO4, and the volatiles were re-
moved in vacuo. The residue was purified by flash column
chromatography [SiO2, cyclohexane (CH)/ethyl acetate (EtOAc)].
Methyl (E)-3-(4-tert-Butylphenyl)propenoate (3e):[28a,30] According
to the GP, 4-tert-butylbenzaldehyde (1e; 188 mg, 1.16 mmol),
methyl bromoacetate (2a; 213 mg, 1.39 mmol), Bu3P=O (38 mg,
0.17 mmol, 15 mol-%), PhSiH3 (188 mg, 1.74 mmol), and 1,2-ep-
oxybutane (167 mg, 2.32 mmol) in dioxane (0.6 mL) were con-
verted for 2 h. Purification (SiO2, CH/EtOAc, 20:1) gave 3e
(170 mg, 67%, E/Z = 94:4) as a yellowish oil. 1H NMR (300 MHz,
CDCl3): δ = 1.34 (s, 9 H, CH3), 3.81 (s, 3 H, CH3), 6.42 (d, J =
16.0 Hz, 1 H, CH), 7.41–7.50 (m, 4 H, ArH), 7.70 (d, J = 16.0 Hz,
1 H, CH) ppm. 13C NMR (75 MHz, CDCl3): δ = 31.00 (3 CH3),
Methyl (E)-Phenylpropenoate (3a):[17a,27] According to the GP, 34.71 (C), 51.43 (CH3), 116.74 (CH), 125.71 (2 CH), 127.81 (2 CH),
benzaldehyde (1a; 162 mg, 1.53 mmol), methyl bromoacetate (2a; 131.50 (C), 144.62 (CH), 153.66 (C), 167.42 (C=O) ppm.
Eur. J. Org. Chem. 2015, 4532–4543
© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
4537

M. Hoffmann, S. Deshmukh, T. Werner
Methyl (E)-3-(2-Methylphenyl)-2-propenoate (3f):[17a,31] According 16.0 Hz, 1 H, CH), 6.93–6.96 (m, 1 H, ArH), 7.04–7.06 (m, 1 H,
FULL PAPER
to the GP, 2-methylbenzaldehyde (1f; 173 mg, 1.44 mmol), methyl
ArH), 7.12–7.14 (m, 1 H, ArH), 7.29–7.34 (m, 1 H, ArH), 7.67 (d,
bromoacetate (2a; 264 mg, 1.73 mmol), Bu3P=O (47 mg, J = 16.0 Hz, 1 H, CH) ppm. 13C NMR (75 MHz, CDCl3): δ =
0.22 mmol, 15 mol-%), PhSiH3 (234 mg, 2.16 mmol), and 1,2-ep- 51.53 (CH3), 55.09 (CH3), 112.86 (CH), 115.97 (CH), 117.94 (CH),
oxybutane (208 mg, 2.88 mmol) in dioxane (0.7 mL) were con-
verted for 2 h. Purification (SiO2, CH/EtOAc, 20:1) gave 3f
(153 mg, 60%, E/Z = 88:12) as a yellowish oil. 1H NMR (300 MHz,
CDCl3): δ = 2.50 (s, 3 H, CH3), 3.87 (s, 3 H, CH3), 6.43 (d, J =
15.9 Hz, 1 H, CH), 7.25–7.34 (m, 3 H, ArH), 7.59–7.63 (m, 1 H,
ArH), 8.05 (d, J = 16.0 Hz, 1 H, CH) ppm. 13C NMR (75 MHz,
CDCl3): δ = 19.64 (CH3), 51.53 (CH3), 118.69 (CH), 126.22 (CH),
126.25 (CH), 129.91 (CH), 130.66 (CH), 133.21 (C), 137.51 (C),
142.38 (CH), 167.31 (C=O) ppm.
120.59 (CH), 129.74 (CH), 135.60 (C), 144.63 (CH), 159.76 (C),
167.18 (C=O) ppm.
(E)-3-(3-Methoxyphenyl)propenenitrile (3jb):[35] According to the
GP, 3-methoxybenzaldehyde (1j; 208 mg, 1.53 mmol), bromoaceto-
nitrile (2e; 220 mg, 1.84 mmol), Bu3P=O (50 mg, 0.23 mmol,
15 mol-%), PhSiH3 (248 mg, 2.30 mmol), and 1,2-epoxybutane
(221 mg, 3.06 mmol) in dioxane (0.8 mL) were converted for 2 h.
Purification (SiO2, CH/EtOAc, 10:1) gave 3jb (214 mg, 88%, E/Z
1
= 83:17) as a yellowish oil. H NMR (300 MHz, CDCl3): δ = 3.84
Methyl (E)-3-(3-Methylphenyl)-2-propenoate (3g):[32] According to
the GP, 3-methylbenzaldehyde (1g; 118 mg, 0.982 mmol), methyl
(s, 3 H, CH3), 5.88 (d, J = 16.6 Hz, 1 H, CH), 6.94–7.14 (m, 3 H,
CH), 7.30–7.44 (m, 2 H, CH) ppm. 13C NMR (75 MHz, CDCl3):
bromoacetate (2a; 180 mg, 1.18 mmol), Bu3P=O (32 mg, δ = 55.21 (CH3), 96.46 (CH), 112.34 (CH), 116.68 (CH), 117.97
0.15 mmol, 15 mol-%), PhSiH3 (159 mg, 1.47 mmol), and 1,2-ep- (C), 119.80 (CH), 129.99 (CH), 134.66 (C), 150.31 (CH), 159.84
oxybutane (141 mg, 1.96 mmol) in dioxane (0.5 mL) were con-
verted for 2 h. Purification (SiO2, CH/EtOAc, 20:1) gave 3g
(104 mg, 60%, E/Z = 90:10) as a yellowish oil. 1H NMR (300 MHz,
CDCl3): δ = 2.38 (s, 3 H, CH3), 3.82 (s, 3 H, CH3), 6.44 (d, J =
16.0 Hz, 1 H, CH), 7.19–7.23 (m, 1 H, ArH), 7.28–7.36 (m, 3 H,
ArH), 7.68 (d, J = 16.0 Hz, 1 H, CH) ppm. 13C NMR (75 MHz,
CDCl3): δ = 21.18 (CH3), 51.53 (CH3), 117.43 (CH), 125.15 (CH),
128.62 (CH), 128.65 (CH), 131.02 (CH), 134.21 (C), 138.41 (C),
144.94 (CH), 167.37 (C=O) ppm.
(C) ppm.
Methyl (E)-2-Methyl-3-(3-methoxyphenyl)propenoate (3jc): Accord-
ing to the GP, 3-methoxybenzaldehyde (1j; 162 mg, 1.19 mmol),
methyl 2-brompropanoate (2f; 238 mg, 1.43 mmol), Bu3P=O
(39 mg, 0.18 mmol, 15 mol-%), PhSiH3 (193 mg, 1.79 mmol), and
1,2-epoxybutane (172 mg, 2.38 mmol) in dioxane (0.6 mL) were
converted for 1 h. Purification (SiO2, CH/EtOAc, 20:1) gave 3jc
(129 mg, 53%, E/Z = 86:14) as a yellowish oil. 1H NMR (300 MHz,
CDCl3): δ = 2.13 (d, J = 1.5 Hz, 3 H, CH3), 3.83 (s, 6 H, CH3),
6.86–6.91 (m, 1 H), 6.92–6.95 (m, 1 H), 6.98–7.02 (m, 1 H), 7.29–
Methyl (E)-3-(4-Methylphenyl)-2-propenoate (3h):[33] According to
the GP, 4-methylbenzaldehyde (1h; 184 mg, 1.53 mmol), methyl 7.35 (m, 1 H), 7.67 (s, 1 H) ppm. 13C NMR (75 MHz, CDCl3): δ =
bromoacetate (2a; 281 mg, 1.84 mmol), Bu3P=O (50 mg, 14.02 (CH3), 51.95 (CH3), 55.09 (CH3), 113.75 (CH), 114.97 (CH),
0.23 mmol, 15 mol-%), PhSiH3 (248 mg, 2.30 mmol), and 1,2-ep- 121.97 (CH), 128.43 (C), 129.26 (CH), 137.06 (C), 138.72 (CH),
oxybutane (221 mg, 3.06 mmol) in dioxane (0.8 mL) were con-
verted for 2 h. Purification (SiO2, CH/EtOAc, 20:1) gave 3h
(163 mg, 60%, E/Z = 97:3) as a colorless solid. 1H NMR
(300 MHz, CDCl3): δ = 2.38 (s, 3 H, CH3), 3.81 (s, 3 H, CH3), 6.41
(d, J = 16.0 Hz, 1 H, CH), 7.19–7.21 (m, 2 H, ArH), 7.42–7.44 (m,
2 H, ArH), 7.68 (d, J = 16.0 Hz, 1 H, CH) ppm. 13C NMR
(75 MHz, CDCl3): δ = 21.41 (CH3), 51.57 (CH3), 116.65 (CH),
128.02 (2 CH), 129.57 (2 CH), 131.61 (C), 140.67 (C), 144.83 (CH),
167.58 (C=O) ppm. C11H12O2 (176.21): calcd. C 74.98, H 6.86;
found C 74.88, H 7.17.
159.34 (C), 168.95 (C=O) ppm. MS (EI, 70 eV): m/z (%) = 206 (72)
[M]+, 175 (25) [M – OMe]+, 146 (100) [M – CO2Me]+, 131 (22),
115 (33), 103 (28), 91 (23). HRMS (EI): calcd. for C12H14O3 [M]+
206.0938; found 206.0937.
Methyl (E)-4-[2-(3-Methoxyphenyl)ethenyl]benzoate (3jd):[36] Ac-
cording to the GP, 3-methoxybenzaldehyde (1j; 178 mg,
1.31 mmol), methyl 4-(chloromethyl)benzoate (2h; 290 mg,
1.57 mmol), Bu3P=O (43 mg, 0.20 mmol, 15 mol-%), PhSiH3
(213 mg, 1.97 mmol), and 1,2-epoxybutane (189 mg, 2.68 mmol) in
dioxane (0.7 mL) were converted for 2 h. Purification (SiO2, CH/
EtOAc, 20:1) gave 3jd (143 mg, 0.533 mmol, 41%, E/Z = 95:5) as
Methyl (E)-3-(2-Methoxyphenyl)propenoate (3i):[28a] According to
the GP, 2-methoxybenzaldehyde (1i; 158 mg, 1.16 mmol), methyl a yellowish oil. 1H NMR (300 MHz, CDCl3): δ = 3.87 (s, 3 H,
bromoacetate (2a; 213 mg, 1.39 mmol), Bu3P=O (38 mg, CH3), 3.94 (s, 3 H, CH3), 6.87 (dd, J = 8.2, J = 0.8 Hz, 1 H, CH),
0.17 mmol, 15 mol-%), PhSiH3 (188 mg, 1.74 mmol), and 1,2-ep- 7.07–7.23 (m, 4 H), 7.30–7.32 (m, 1 H), 7.56–7.59 (m, 2 H), 8.02–
oxybutane (167 mg, 2.32 mmol) in dioxane (0.6 mL) were con-
verted for 2 h. Purification (SiO2, CH/EtOAc, 20:1) gave 3i
(144 mg, 65%, E/Z = 87:13) as a yellowish oil. 1H NMR (300 MHz,
8.05 (m, 2 H) ppm. 13C NMR (75 MHz, CDCl3): δ = 51.96 (CH3),
55.12 (CH3), 111.90 (CH), 113.77 (CH), 119.38 (CH), 126.24 (2
CH), 127.70 (CH), 128.80 (C), 129.63 (CH), 129.90 (2 CH), 130.98
CDCl3): δ = 3.81 (s, 3 H, CH3), 3.90 (s, 3 H, CH3), 6.55 (d, J = (CH), 138.05 (C), 141.58 (C), 159.80 (C), 166.73 (C=O) ppm.
16.2 Hz, 1 H, CH), 6.87–7.00 (m, 2 H, ArH), 7.33–7.39 (m, 1 H,
(E)-1-(3-Methoxyphenyl)-2-(4-trifluoromethylphenyl)ethene (3je):[37]
ArH), 7.50–7.53 (m, 1 H, ArH), 8.01 (d, J = 16.0 Hz, 1 H, CH)
According to the GP, 3-methoxybenzaldehyde (1j; 182 mg,
ppm. 13C NMR (75 MHz, CDCl3): δ = 51.41 (CH3), 55.27 (CH3),
1.43 mmol), 4-(trifluoromethyl)benzyl chloride (2j; 313 mg,
110.98 (CH), 118.11 (CH), 120.54 (CH), 123.15 (C), 128.73 (CH),
1.61 mmol), Bu3P=O (44 mg, 0.20 mmol, 15 mol-%), PhSiH3
131.37 (CH), 140.11 (CH), 158.18 (C), 167.77 (C=O) ppm.
(218 mg, 2.01 mmol), and 1,2-epoxybutane (193 mg, 2.68 mmol) in
C11H12O3 (192.21): calcd. C 68.74, H 6.29; found C 68.24, H 6.24.
dioxane (0.7 mL) were converted for 2 h. Purification (SiO2, CH/
Methyl (E)-3-(3-Methoxyphenyl)propenoate (3ja):[34] According to
the GP, 3-methoxybenzaldehyde (1j; 119 mg, 0.874 mmol), methyl solid. H NMR (300 MHz, CDCl3): δ = 3.76 (s, 3 H, CH3), 6.63–
bromoacetate (2a; 150 mg, 0.981 mmol), Bu3P=O (27 mg, 6.73 (m, 1 H), 6.75–6.79 (m, 1 H), 6.97–7.06 (m, 4 H), 7.16–7.25
0.12 mmol, 15 mol-%), PhSiH3 (133 mg, 1.23 mmol), and 1,2-ep- (m, 1 H), 7.47–7.55 (m, 3 H) ppm. 13C NMR (75 MHz, CDCl3): δ
EtOAc, 20:1) gave 3je (205 mg, 55%, E/Z = 78:22) as a colorless
1
oxybutane (118 mg, 1.64 mmol) in dioxane (0.4 mL) were con-
verted for 3 h. Purification (SiO2, CH/EtOAc, 10:1) gave 3ja
(125 mg, 75%, E/Z = 90:10) as a yellowish oil. 1H NMR (300 MHz,
= 55.22 (CH3), 112.00 (CH), 113.88 (CH), 119.44 (CH), 124.21 (q,
3
1JC,F = 272.0 Hz, C), 125.58 (q, JC,F = 3.8 Hz, 2 CH), 126.58 (2
2
CH), 127.35 (CH), 129.21 (q, JC,F = 32.5 Hz, C), 129.74 (CH),
CDCl3): δ = 3.82 (s, 3 H, CH3), 3.84 (s, 3 H, CH3), 6.44 (d, J = 131.05 (CH), 138.03 (C), 140.66 (C), 159.91 (C) ppm. MS (EI,
4538
www.eurjoc.org
© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2015, 4532–4543

The Microwave-Assisted Catalytic Wittig Reaction
70 eV): m/z (%) = 278 (100) [M]+, 262 (16), 209 (18) [M – CF3]+,
194 (20), 178 (20), 165 (46). C16H13FO3 (272.27): calcd. C 69.06,
H 4.71; found C 69.29, H 4.55.
Methyl (E)-3-(4-Methoxycarbonylphenyl)-2-propenoate (3n):[40] Ac-
cording to the GP, 4-(methoxycarbonyl)benzaldehyde (1n; 200 mg,
1.22 mmol), methyl bromoacetate (2a; 224 mg, 1.46 mmol),
Bu3P=O (40 mg, 0.18 mmol, 15 mol-%), PhSiH3 (198 mg,
1.83 mmol), and 1,2-epoxybutane (176 mg, 2.44 mmol) in dioxane
(0.6 mL) were converted for 2 h. Purification (SiO2, CH/EtOAc,
5:1) gave 3n (175 mg, 65%, E/Z = 92:8) as a colorless solid. 1H
NMR (300 MHz, CDCl3): δ = 3.83 (s, 3 H, CH3), 3.94 (s, 3 H,
CH3), 6.53 (d, J = 16.1 Hz, 1 H, CH), 7.57–7.62 (m, 2 H, ArH),
(E)-1-(3-Methoxyphenyl)-2-(3-trifluoromethylphenyl)ethene
(3jf):
According to the GP, 3-methoxybenzaldehyde (1j; 221 mg,
1.62 mmol), 3-(trifluoromethyl)benzyl bromide (2l; 465 mg,
1.94 mmol), Bu3P=O (53 mg, 0.24 mmol, 15 mol-%), PhSiH3
(263 mg, 2.43 mmol), and 1,2-epoxybutane (234 mg, 3.24 mmol) in
dioxane (0.8 mL) were converted for 2 h. Purification (SiO2, CH/
EtOAc, 20:1) gave 3jf (262 mg, 58%, E/Z = 75:25) as a colorless
oil. 1H NMR (300 MHz, CDCl3): δ = 4.00 (s, 3 H, CH3), 6.72–7.04
(m, 2 H), 7.21–7.24 (m, 1 H), 7.27–7.35 (m, 1 H), 7.39–7.50 (m, 1
H), 7.56–7.69 (m, 3 H), 7.78–7.84 (m, 1 H), 7.90–7.92 (m, 1 H)
7.72 (d, J = 16.1 Hz, 1 H, CH), 8.01–8.08 (m, 2 H, ArH) ppm. 13
C
NMR (75 MHz, CDCl3): δ = 51.53 (CH3), 51.94 (CH3), 119.86
(CH), 127.62 (2 CH), 129.77 (2 CH), 131.06 (C), 138.25 (C), 143.06
(CH), 166.00 (C=O), 166.55 (C=O) ppm.
ppm. 13C NMR (75 MHz, CDCl3): δ = 55.07 (CH3), 111.90 (CH),
Methyl (E)-3-(4-Fluorophenyl)propenoate (3o):[41] According to the
3
113.76 (CH), 119.32 (CH), 123.03 (q, JC,F = 3.8 Hz, CH), 123.99 GP, 4-fluorobenzaldehyde (1o; 155 mg, 1.25 mmol), methyl bromo-
3
1
(q, JC,F = 3.8 Hz, CH), 124.16 (q, JC,F = 272.3 Hz, C), 127.27
acetate (2a; 230 mg, 1.50 mmol), Bu3P=O (41 mg, 0.19 mmol,
15 mol-%), PhSiH3 (202 mg, 1.87 mmol), and 1,2-epoxybutane
(180 mg, 2.49 mmol) in dioxane (0.6 mL) were converted for 3 h.
(CH), 129.04 (CH), 129.51 (CH), 129.68 (CH), 130.33 (CH), 130.98
2
(q, JC,F = 32.1 Hz, C), 137.96 (C), 138.04 (C), 159.90 (C) ppm.
MS (EI, 70 eV): m/z (%) = 278 (100) [M]+, 277 (18), 262 (13), 209 Purification (SiO2, CH/EtOAc, 20:1) gave a mixture of 3o (118 mg,
(10) [M – CF3]+, 178 (15), 165 (33). HRMS (EI): calcd. for 52%, E/Z = 99:1) and methyl 3-(4-fluorophenyl)propanoate (7 mg,
C16H13F3O [M]+ 278.0913; found 278.0913.
4%) as a colorless solid. Data for 3o: 1H NMR (300 MHz, CDCl3):
δ = 3.81 (s, 3 H, CH3), 6.37 (d, J = 16.0 Hz, 1 H), 7.05–7.12 (m, 2
H, ArH), 7.49–7.55 (m, 2 H, ArH), 7.66 (d, J = 16.0 Hz, 1 H) ppm.
Methyl (E)-3-(2-Methoxyphenyl)propenoate (3k):[38] According to
the GP, 4-methoxybenzaldehyde (1k; 178 mg, 1.31 mmol), methyl
bromoacetate (2a; 240 mg, 1.57 mmol), Bu3P=O (43 mg,
0.20 mmol, 15 mol-%), PhSiH3 (213 mg, 1.97 mmol), and 1,2-ep-
oxybutane (189 mg, 2.62 mmol) in dioxane (0.7 mL) were con-
verted for 2 h. Purification (SiO2, CH/EtOAc, 20:1) gave 3k
(141 mg, 56%, E/Z = 95:5) as a yellowish solid. 1H NMR
(300 MHz, CDCl3): δ = 3.80 (s, 3 H, CH3), 3.84 (s, 3 H, CH3), 6.32
13C NMR (75 MHz, CDCl3): δ = 51.65 (CH3), 115.96 (d, JC,F
=
21.9 Hz, 2 CH), 117.46 (CH), 129.87 (d, JC,F = 8.5 Hz, 2 CH),
130.55 (d, JC,F = 3.4 Hz, C), 143.48 (CH), 163.83 (d, JC,F
=
251.3 Hz, C), 167.23 (C=O) ppm.
Methyl (E)-3-(2-Chlorophenyl)propenoate (3p):[29,33a] According to
the GP, 2-chlorobenzaldehyde (1p; 215 mg, 1.53 mmol), methyl
(d, J = 15.9 Hz, 1 H, CH), 6.89–6.93 (m, 2 H, ArH), 7.47–7.50 (m, bromoacetate (2a; 280 mg, 1.83 mmol), Bu3P=O (50 mg,
2 H, ArH), 7.66 (d, J = 15.9 Hz, 1 H, CH) ppm. 13C NMR 0.23 mmol, 15 mol-%), PhSiH3 (248 mg, 2.29 mmol), and 1,2-ep-
(75 MHz, CDCl3): δ = 51.45 (CH3), 55.24 (CH3), 114.23 (2 CH), oxybutane (220 mg, 3.05 mmol) in dioxane (0.5 mL) were con-
115.16 (CH), 127.01 (C), 129.63 (2 CH), 144.42 (CH), 161.31 (C),
verted for 2 h. Purification (SiO2, CH/EtOAc, 20:1) gave a mixture
167.64 (C=O) ppm. C11H12O3 (192.21): calcd. C 68.74, H 6.29; of 3p (156 mg, 52%, E/Z = 96:4) and methyl 3-(2-chlorophenyl)-
found C 68.63, H 6.28.
propanoate (9 mg, 3%) as a colorless oil. Data for 3p: 1H NMR
(300 MHz, CDCl3): δ = 3.80 (s, 3 H, CH3), 6.41 (d, J = 16.0 Hz, 1
H, CH), 7.23–7.30 (m, 2 H, ArH), 7.38–7.42 (m, 1 H, ArH), 7.57–
7.61 (m, 1 H, ArH), 8.08 (d, J = 16.0 Hz, 1 H, CH) ppm. 13C NMR
(75 MHz, CDCl3): δ = 51.75 (CH3), 120.39 (CH), 127.01 (CH),
127.54 (CH), 130.09 (CH), 130.98 (CH), 132.58 (C), 134.86 (C),
140.52 (CH), 166.80 (C=O) ppm.
Methyl (E)-3-(2-Methoxycarbonylphenyl)-2-propenoate (3l):[34,39]
According to the GP, 2-(methoxycarbonyl)benzaldehyde (1l;
236 mg, 1.44 mmol), methyl bromoacetate (2a; 264 mg,
1.73 mmol), Bu3P=O (47 mg, 0.22 mmol, 15 mol-%), PhSiH3
(234 mg, 2.16 mmol), and 1,2-epoxybutane (208 mg, 2.88 mmol) in
dioxane (0.7 mL) were converted for 2 h. Purification (SiO2, CH/
EtOAc, 10:1) gave 3l (192 mg, 60%, E/Z = 77:23) as a colorless oil. Methyl (E)-3-(3-Chlorophenyl)propenoate (3q):[29] According to the
1H NMR (300 MHz, CDCl3): δ = 3.81 (s, 3 H, CH3), 3.93 (s, 3 H,
CH3), 6.31 (d, J = 15.9 Hz, 1 H, CH), 7.33–7.61 (m, 3 H, ArH),
GP, 3-chlorobenzaldehyde (1q; 153 mg, 1.09 mmol), methyl bromo-
acetate (2a; 202 mg, 1.32 mmol), Bu3P=O (36 mg, 0.16 mmol,
15 mol-%), PhSiH3 (178 mg, 1.64 mmol), and 1,2-epoxybutane
7.94–7.98 (m, 1 H, ArH), 8.45 (d, J = 15.9 Hz, 1 H, CH) ppm. 13
C
NMR (75 MHz, CDCl3): δ = 51.64 (CH3), 52.26 (CH3), 120.53 (157 mg, 2.18 mmol) in dioxane (0.5 mL) were converted for 3 h.
(CH), 127.77 (CH), 129.27 (CH), 129.61 (C), 130.63 (CH), 132.25 Purification (SiO2, CH/EtOAc, 20:1) gave 3q (112 mg, 52%, E/Z =
1
(CH), 136.20 (C), 143.78 (CH), 166.84 (C=O), 166.99 (C=O) ppm. 97:3) as a colorless oil. H NMR (300 MHz, CDCl3): δ = 3.82 (s,
3 H, CH3), 6.45 (d, J = 16.0 Hz, 1 H, CH), 7.32–7.42 (m, 3 H,
Methyl (E)-3-(3-Methoxycarbonylphenyl)-2-propenoate (3m):[34] Ac-
ArH), 7.50–7.52 (m, 1 H, ArH), 7.63 (d, J = 16.0 Hz, 1 H, CH)
cording to the GP, 3-(methoxycarbonyl)benzaldehyde (1m; 156 mg,
ppm. 13C NMR (75 MHz, CDCl3): δ = 51.74 (CH3), 119.19 (CH),
0.950 mmol), methyl bromoacetate (2a; 174 mg, 1.14 mmol),
126.16 (CH), 127.71 (CH), 130.05 (CH), 130.06 (CH), 134.82 (C),
Bu3P=O (31 mg, 0.14 mmol, 15 mol-%), PhSiH3 (154 mg,
136.11 (C), 143.13 (CH), 166.89 (C=O) ppm.
1.43 mmol), and 1,2-epoxybutane (137 mg, 1.90 mmol) in dioxane
(0.5 mL) were converted for 2 h. Purification (SiO2, CH/EtOAc,
Methyl (E)-3-(4-Chlorophenyl)propenoate (3r):[42] According to the
GP, 4-chlorobenzaldehyde (1r; 180 mg, 1.28 mmol), methyl bromo-
acetate (2a; 235 mg, 1.54 mmol), Bu3P=O (42 mg, 0.19 mmol,
1
10:1) gave 3m (144 mg, 69%, E/Z = 95:5) as a colorless solid. H
NMR (300 MHz, CDCl3): δ = 3.83 (s, 3 H, CH3), 3.95 (s, 3 H,
CH3), 6.53 (d, J = 16.1 Hz, 1 H, CH), 7.48 (t, J = 7.8 Hz, 1 H), 15 mol-%), PhSiH3 (111 mg, 1.02 mmol), and 1,2-epoxybutane
7.69–7.76 (m, 2 H, ArH), 8.21–8.22 (m, 1 H, ArH), 8.05 (d, J =
(185 mg, 2.56 mmol) in dioxane (0.6 mL) were converted for 2 h.
Purification (SiO2, CH/EtOAc, 20:1) gave 3r (127 mg, 50%, E/Z =
16.1 Hz, 1 H, CH) ppm. 13C NMR (75 MHz, CDCl3): δ = 51.78
(CH3), 52.29 (CH3), 119.05 (CH), 128.93 (CH), 128.97 (CH), 95:5) as a colorless solid. 1H NMR (300 MHz, CDCl3): δ = 3.82
130.78 (C), 131.02 (CH), 132.15 (CH), 134.66 (C), 143.57 (CH), (s, 3 H, CH3), 6.42 (d, J = 16.0 Hz, 1 H, CH), 7.35–7.39 (m, 2 H,
166.39 (C=O), 167.03 (C=O) ppm.
ArH), 7.45–7.48 (m, 2 H, ArH), 7.65 (d, J = 16.0 Hz, 1 H, CH)
Eur. J. Org. Chem. 2015, 4532–4543
© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
4539

M. Hoffmann, S. Deshmukh, T. Werner
FULL PAPER
ppm. 13C NMR (75 MHz, CDCl3): δ = 51.51 (CH3), 118.17 (CH),
128.93 (2 CH), 129.01 (2 CH), 132.65 (C), 135.94 (C), 143.11 (CH),
166.84 (C=O) ppm. C10H9ClO3 (212.63): calcd. C 61.08, H 4.61,
Cl 18.03; found C 60.99, H 4.33, Cl 17.90.
Methyl (E)-3-(3-Bromophenyl)propenoate (3s):[43] According to the
GP, 3-bromobenzaldehyde (1s; 305 mg, 1.65 mmol), methyl bromo-
acetate (2a; 303 mg, 1.98 mmol), Bu3P=O (54 mg, 0.25 mmol,
15 mol-%), PhSiH3 (268 mg, 2.48 mmol), and 1,2-epoxybutane
(238 mg, 3.30 mmol) in dioxane (0.8 mL) were converted for 2 h.
Purification (SiO2, CH/EtOAc, 10:1) gave a mixture of 3s (224 mg,
reddish oil. H NMR (300 MHz, CDCl3): δ = 3.80 (s, 3 H, CH3),
6.25 (d, J = 15.7 Hz, 1 H, CH), 7.04–7.08 (m, 1 H, ArH), 7.25–
7.27 (m, 1 H, ArH), 7.37–7.39 (m, 1 H, ArH), 7.80 (d, J = 15.7 Hz,
1 H, CH) ppm. 13C NMR (75 MHz, CDCl3): δ = 51.49 (CH3),
116.34 (CH), 127.92 (CH), 128.32 (CH), 130.80 (CH), 137.11 (CH),
139.31 (C), 167.06 (C=O) ppm.
1
Methyl (E)-3-(2-Benzofuranyl)propenoate (3x):[48] According to the
GP, benzofuran-2-carbaldehyde (2x; 161 mg, 1.10 mmol), methyl
bromoacetate (2a; 202 mg, 1.32 mmol), Bu3P=O (36 mg,
0.17 mmol), PhSiH3 (179 mg, 1.65 mmol), and 1,2-epoxybutane
(159 mg, 2.20 mmol) in dioxane (0.6 mL) were converted for 2 h.
Purification (SiO2, CH/EtOAc, 20:1) gave 3x (130 mg, 58%, E/Z =
53%, E/Z
= 99:1) and methyl 3-(3-bromophenyl)propanoate
(25 mg, 10%) as a colorless solid. Data for 3s: 1H NMR (300 MHz,
CDCl3): δ = 3.81 (s, 3 H, CH3), 6.42 (d, J = 16.0 Hz, 1 H, CH),
7.22–7.26 (m, 1 H, ArH), 7.41–7.44 (m, 1 H, ArH), 7.48–7.50 (m,
1 H, ArH), 7.59 (d, J = 16.0 Hz, 1 H, CH), 7.63–7.67 (m, 1 H,
ArH) ppm. 13C NMR (75 MHz, CDCl3): δ = 51.63 (CH3), 119.09
(CH), 122.83 (C), 126.48 (CH), 130.19 (CH), 130.55 (CH), 132.85
(CH), 136.26 (C), 142.89 (CH), 166.69 (C=O) ppm.
1
91:9) as a yellowish solid. H NMR (300 MHz, CDCl3): δ = 3.83
(s, 3 H, CH3), 6.59 (d, J = 15.6 Hz, 1 H, CH), 6.90–6.95 (m, 1 H,
CH), 7.22–7.28 (m, 1 H, CH), 7.33–7.40 (m, 1 H, CH), 7.45–7.52
(m, 1 H, CH), 7.54–7.61 (m, 3 H, CH) ppm. 13C NMR (75 MHz,
CDCl3): δ = 51.68 (CH3), 111.10 (CH), 111.28 (CH), 118.31 (CH),
121.63 (CH), 123.20 (CH), 126.34 (CH), 128.20 (C), 131.33 (CH),
152.13 (C), 155.41 (C), 166.97 (C=O) ppm.
Methyl (E)-3-(4-Bromophenyl)propenoate (3t):[43,44] According to
the GP, 4-bromobenzaldehyde (1t; 305 mg, 1.65 mmol), methyl
bromoacetate (2a; 303 mg, 1.98 mmol), Bu3P=O (54 mg,
0.25 mmol, 15 mol-%), PhSiH3 (268 mg, 2.48 mmol), and 1,2-ep-
oxybutane (238 mg, 3.30 mmol) in dioxane (0.8 mL) were con-
verted for 2 h. Purification (SiO2, CH/EtOAc, 20:1) gave 3t
(244 mg, 61%, E/Z = 98:2) as a colorless solid. 1H NMR
(300 MHz, CDCl3): δ = 3.81 (s, 3 H, CH3), 6.43 (d, J = 16.0 Hz, 1
H, CH), 7.37–7.41 (m, 2 H, ArH), 7.51–7.54 (m, 2 H, ArH), 7.63
(d, J = 16.0 Hz, 1 H, CH) ppm. 13C NMR (75 MHz, CDCl3): δ =
51.66 (CH3), 118.34 (CH), 124.41 (C), 129.31 (2 CH), 131.99 (2
CH), 133.13 (C), 143.31 (CH), 166.96 (C=O) ppm.
Methyl (E)-5,9-Dimethyldeca-2,8-dienoate (5a):[17a,17b] According to
the GP, 3,7-dimethyloct-6-enal (4a; 159 mg, 1.03 mmol), methyl
bromoacetate (2a; 189 mg, 1.24 mmol), Bu3P=O (34 mg,
0.16 mmol, 15 mol-%), PhSiH3 (167 mg, 1.55 mmol) and 1,2-ep-
oxybutane (149 mg, 2.06 mmol) in dioxane (0.5 mL) were con-
verted for 1 h. Purification (SiO2, CH/EtOAc, 20:1) gave 5a
1
(124 mg, 57%, E/Z = 93:7) as a colorless oil. H NMR (300 MHz,
CDCl3): δ = 0.91 (d, J = 6.7 Hz, 3 H, CH3), 1.12–1.42 (m, 3 H,
CH2), 1.59–1.63 (m, 3 H, CH3), 1.66–1.71 (m, 3 H, CH3), 1.91–
2.10 (m, 3 H, CH2), 2.17–2.27 (m, 1 H, CH), 3.73 (s, 3 H, CH3),
5.05–5.12 (m, 1 H), 5.82 (dt, J = 15.6, J = 1.5 Hz, 1 H, CH), 6.90–
7.01 (m, 1 H) ppm. 13C NMR (75 MHz, CDCl3): δ = 17.50 (CH),
19.34 (CH3), 25.36 (CH2), 25.57 (CH3), 31.95 (CH3), 36.54 (CH2),
39.52 (CH2), 51.20 (CH3), 121.86 (CH), 124.27 (CH), 131.28 (C),
148.37 (CH), 166.86 (C=O) ppm.
Methyl (E)-3-(2-Trifluoromethylphenyl)propenoate (3u):[45] Accord-
ing to the GP, 2-trifluoromethylbenzaldehyde (1u; 352 mg,
1.89 mmol), methyl bromoacetate (2a; 348 mg, 2.27 mmol),
Bu3P=O (62 mg, 0.28 mmol, 15 mol-%), PhSiH3 (306 mg,
2.83 mmol) and 1,2-epoxybutane (272 mg, 3.77 mmol) in dioxane
(0.5 mL) were converted for 2 h. Purification (SiO2, CH/EtOAc,
20:1) gave 3u (197 mg, 54%, E/Z = 73:27) as a yellowish oil. 1H
NMR (300 MHz, CDCl3): δ = 3.84 (s, 3 H, CH3), 6.42 (d, J =
15.8 Hz, 1 H, CH), 7.40–7.74 (m, 4 H), 8.04–8.11 (m, 1 H, ArH)
ppm. 13C NMR (75 MHz, CDCl3): δ = 51.87 (CH3), 122.11 (CH),
Methyl (E)-Trideca-2,12-dienoate (5b):[49] According to the GP, 10-
undecenal (4b; 282 mg, 1.67 mmol), methyl bromoacetate (2a;
307 mg, 2.01 mmol), Bu3P=O (55 mg, 0.25 mmol), PhSiH3
(272 mg, 2.51 mmol), and 1,2-epoxybutane (241 mg, 3.35 mmol) in
dioxane (0.8 mL) were converted for 1 h. Purification (SiO2, CH/
EtOAc, 20:1) gave 5b (312 mg, 83%, E/Z = 93:7) as a colorless oil.
1H NMR (300 MHz, CDCl3): δ = 1.25–1.50 (m, 12 H, CH2), 2.00–
2.09 (m, 2 H, CH2), 2.16–2.24 (m, 2 H, CH2), 3.73 (s, 3 H, CH3),
4.90–5.04 (m, 2 H, CH), 5.75–5.89 (m, 2 H, CH), 6.98 (dt, J =
15.6, J = 7.0 Hz, 1 H, CH) ppm. 13C NMR (75 MHz, CDCl3): δ
= 27.91 (CH2), 28.80 (CH2), 28.99 (CH2), 29.01 (CH2), 29.24
(CH2), 29.26 (CH2), 32.11 (CH2), 33.69 (CH2), 51.22 (CH3), 114.05
(CH), 120.73 (CH), 139.00 (CH), 149.64 (CH), 167.03 (C=O) ppm.
1
3
123.86 (q, JC,F = 273.0 Hz, CF3), 126.11 (q, JC,F = 5.6 Hz, CH),
2
127.84 (CH), 128.80 (q, JC,F = 30.4 Hz, C), 129.56 (CH), 132.06
3
(CH), 133.28 (C), 140.25 (d, JC,F = 2.0 Hz, CH), 166.48 (C=O)
ppm. 19F NMR (282 MHz, CDCl3): δ = –58.56 ppm.
Methyl (E)-3-(2-Furyl)propenoate (3v):[40,46] According to the GP,
2-furylcarbaldehyde (2v; 83 mg, 0.86 mmol), methyl bromoacetate
(2a; 158 mg, 1.03 mmol), Bu3P=O (28 mg, 0.13 mmol, 15 mol-%),
PhSiH3 (140 mg, 1.29 mmol), and 1,2-epoxybutane (124 mg,
1.72 mmol) in dioxane (0.4 mL) were converted for 2 h. Purification
(SiO2, CH/EtOAc, 20:1) gave 3v (47 mg, 36%, E/Z = 90:10) as an
Methyl (E)-6-(5,5-Dimethyl-1,3-dioxanyl)hex-2-enoate (5c): Accord-
ing to the GP, 4-(5,5-dimethyl-1,3-dioxanyl)butyraldehyde (4c;
397 mg, 2.13 mmol), methyl bromoacetate (2a; 392 mg,
2.56 mmol), Bu3P=O (70 mg, 0.32 mmol, 15 mol-%), PhSiH3
(346 mg, 3.20 mmol), and 1,2-epoxybutane (308 mg, 4.26 mmol) in
dioxane (1.1 mL) were converted for 2 h. Purification (SiO2, CH/
EtOAc, 20:1) gave 5c (310 mg, 60%, E/Z = 93:7) as a colorless oil.
1H NMR (300 MHz, CDCl3): δ = 0.71 (s, 3 H, CH3), 1.18 (s, 3 H,
CH3), 1.53–1.72 (m, 4 H, CH2), 2.18–2.26 (m, 2 H, CH2), 3.38–
1
orange oil. H NMR (300 MHz, CDCl3): δ = 3.79 (s, 3 H, CH3),
6.32 (d, J = 15.7 Hz, 1 H, CH), 6.46–6.48 (m, 1 H, ArH), 6.60–
6.63 (m, 1 H, ArH), 7.44 (d, J = 15.7 Hz, 1 H, CH), 7.48–7.49 (m,
1 H, ArH) ppm. 13C NMR (75 MHz, CDCl3): δ = 51.55 (CH3),
112.19 (CH), 114.74 (CH), 115.33 (CH), 131.11 (CH), 144.67 (CH),
150.77 (C), 167.39 (C=O) ppm.
Methyl (E)-3-(2-Thienyl)propenoate (3w):[47] According to the GP, 3.44 (m, 2 H, OCH2), 3.56–3.61 (m, 2 H, OCH2), 3.71 (s, 3 H,
2-thienylcarbaldehyde (2w; 140 mg, 1.25 mmol), methyl bromoacet-
ate (2a; 229 mg, 1.50 mmol), Bu3P=O (41 mg, 0.19 mmol, 15 mol-
%), PhSiH3 (203 mg, 1.88 mmol), and 1,2-epoxybutane (180 mg,
2.50 mmol) in dioxane (0.6 mL) were converted for 2 h. Purification
(SiO2, CH/EtOAc, 10:1) gave 3w (123 mg, 58%, E/Z = 88:12) as a
CH3), 4.40–4.45 (m, 1 H, CH), 5.82 (dt, J = 15.6, J = 1.6 Hz, 1 H,
CH), 6.96 (dt, J = 15.6, J = 6.9 Hz, 1 H, CH) ppm. 13C NMR
(75 MHz, CDCl3): δ = 21.62 (CH3), 22.09 (CH2), 22.76 (CH3),
29.91 (C), 31.78 (CH2), 33.97 (CH2), 51.11 (CH3), 76.95 (2 CH2),
101.45 (CH), 120.96 (CH), 148.89 (CH), 166.77 (C=O) ppm. MS
4540
www.eurjoc.org
© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2015, 4532–4543

The Microwave-Assisted Catalytic Wittig Reaction
(EI, 70 eV): m/z (%) = 242 (1) [M]+, 141 (21), 125 (52), 115 (100),
(75 MHz, CDCl3): δ = 38.33 (CH2), 51.32 (CH3), 121.81 (CH),
126.56 (CH), 128.57 (2 CH), 128.66 (2 CH), 137.51 (C), 147.48
(CH), 166.73 (C=O) ppm.
[M – C H O ]+, 81 (17), 69 (73), 56 (42). IR (ATR): ν = 2952 (m),
˜
7
11
2
2846 (w), 1721 (vs), 1656 (m), 1436 (m), 1394 (w), 1312 (m), 1270
(s), 1195 (s), 1165 (s), 1132 (vs), 1110 (s), 1039 (m), 1017 (s), 980
(s), 940 (w), 923 (m), 855 (m), 817 (m), 784 (s), 719 (m), 665 (m)
cm–1. C13H22O4 (242.31): calcd. C 64.44, H 9.15; found C 64.06, H
9.18.
Methyl (E)-4-(4-Diphenyl)but-2-enoate (5h):[53] According to the
GP, diphenylacetaldehyde (4h; 279 mg, 1.42 mmol), methyl bromo-
acetate (2a; 261 mg, 1.70 mmol), Bu3P=O (31 mg, 0.14 mmol),
PhSiH3 (230 mg, 2.13 mmol), and 1,2-epoxybutane (205 mg,
2.84 mmol) in dioxane (0.71 mL) were converted for 1 h. Purifica-
tion (SiO2, CH/EtOAc, 20:1) gave a colorless oil, a mixture of prod-
uct 5h (245 mg, 68%, E/Z = 97:3) and isomerised product methyl
4-(4-diphenyl)but-3-enoate (63 mg, 11%). Data for 5h: 1H NMR
(300 MHz, CDCl3): δ = 3.74 (s, 3 H, CH3), 4.90 (d, J = 7.3 Hz, 1
H, CH), 5.76 (dd, J = 15.6, J = 1.5 Hz, 1 H, CH), 7.16–7.36 (m,
10 H, CH), 7.42–7.52 (m, 1 H, CH) ppm. 13C NMR (75 MHz,
CDCl3): δ = 51.44 (CH3), 53.30 (CH), 122.42 (CH), 126.82 (2 CH),
128.48 (4 CH), 128.58 (4 CH), 141.36 (2 C), 150.06 (CH), 166.72
(C=O) ppm.
Methyl (E)-5-Phenylpent-2-enoate (5d):[50] According to the GP, 3-
phenylpropanal (4d; 191 mg, 1.42 mmol), methyl bromoacetate (2a;
261 mg, 1.70 mmol), Bu3P=O (31 mg, 0.14 mmol, 10 mol-%),
PhSiH3 (230 mg, 2.13 mmol), and 1,2-epoxybutane (205 mg,
2.84 mmol) in dioxane (0.7 mL) were converted for 2 h. Purification
(SiO2, CH/EtOAc, 20:1) gave 5d (200 mg, 74%, E/Z = 91:9) as a
1
colorless oil. H NMR (300 MHz, CDCl3): δ = 2.50–2.59 (m, 2 H,
CH2), 2.76–2.82 (t, J = 7.7 Hz, 2 H, CH2), 3.74 (s, 3 H, CH3), 5.87
(dt, J = 15.7, J = 1.6 Hz, 1 H, CH), 7.03 (dt, J = 15.7, J = 6.8 Hz,
1 H, CH), 7.17–7.25 (m, 3 H, ArH), 7.27–7.34 (m, 2 H, ArH) ppm.
13C NMR (75 MHz, CDCl3): δ = 33.85 (CH2), 34.29 (CH2), 51.40
(CH3), 121.41 (CH), 126.14 (CH), 128.29 (2 CH), 128.45 (2 CH),
140.70 (C), 148.33 (CH), 166.96 (C=O) ppm.
(R)-5-Methylbicyclo[3.3.0]oct-1-ene-3,6-dione (9):[23e] Ketone
8
(241 mg, 0.98 mmol), PhSiH3 (159 mg, 1.47 mmol), 1,2-butylene
oxide (141 mg, 1.96 mmol), and (R,R)-Me-BPE (13; 12.6 mg,
0.049 mmol, 5 mol-%) in 1,4-dioxane (0.5 mL) were converted for
20 h according to the GP to give alkene R-9 (93 mg, 0.619 mmol,
Methyl (E)-5-Phenylpentadienoate (5e):[51] According to the GP, 3-
phenylpropenal (5e; 209 mg, 93% purity, 1.47 mmol), methyl
bromoacetate (2a; 270 mg, 1.76 mmol), Bu3P=O (48 mg,
0.22 mmol, 15 mol-%), PhSiH3 (239 mg, 2.21 mmol), and 1,2-ep-
oxybutane (212 mg, 2.94 mmol) in dioxane (0.7 mL) were con-
verted for 3 h. Purification (SiO2, CH/EtOAc, 20:1) gave 5e
(143 mg, 52%, E/Z = 95:5) as a colorless solid. 1H NMR
(300 MHz, CDCl3): δ = 3.79 (s, 3 H, CH3), 6.01 (d, J = 15.3 Hz, 1
H, CH), 6.88–6.91 (m, 2 H), 7.32–7.51 (m, 6 H) ppm. 13C NMR
(75 MHz, CDCl3): δ = 51.38 (CH3), 120.65 (CH), 126.00 (CH),
127.06 (2 CH), 128.64 (2 CH), 128.91 (CH), 135.81 (C), 140.39
(CH), 144.67 (CH), 167.27 (C=O) ppm. MS (EI, 70 eV): m/z (%)
= 188 (21) [M]+, 157 (17) [M – OMe]+, 129 (100) [M – CO2Me]+.
HRMS (EI): calcd. for C12H12O2 [M]+ 188.0832; found 188.0829.
1
63%, 32% ee) as a colorless oil. H NMR (300 MHz, CDCl3): δ =
1.35 (s, 3 H, CH3), 2.28–2.64 (m, 3 H, CH2), 2.91–3.20 (m, 3 H,
CH2), 5.97 (s, 1 H, CH) ppm. 13C NMR (75 MHz, CDCl3): δ =
23.19 (CH3), 24.39 (CH2), 38.25 (CH2), 44.66 (CH2), 56.74 (C),
126.12 (CH), 184.71 (C), 207.58 (C=O), 212.47 (C=O) ppm.
Acknowledgments
The advice and support of Prof. Beller is gratefully acknowledged.
[1] a) W.-Y. Siau, Y. Zhang, Y. Zhao, in: Top. Curr. Chem. vol.
327: Stereoselective Alkene Synthesis (Ed.: J. Wang), Springer,
Berlin, 2012, p. 33–58; b) Y. Chauvin, Angew. Chem. Int. Ed.
2006, 45, 3740–3747; Angew. Chem. 2006, 118, 3824–3831; c)
R. R. Schrock, Angew. Chem. Int. Ed. 2006, 45, 3748–3759;
Angew. Chem. 2006, 118, 3832–3844; d) R. H. Grubbs, Angew.
Chem. Int. Ed. 2006, 45, 3760–3765; Angew. Chem. 2006, 118,
3845–3850; e) K. C. Nicolaou, S. A. Snyder, Classics in Total
Synthesis II. More Targets, Strategies, Methods, Wiley-VCH,
Weinheim, Germany, 2003; f) K. C. Nicolaou, E. J. Sørensen,
Classics in Total Synthesis VCH-Verlagsgesellschaft, Weinheim,
Germany, 1996.
[2] R. C. Larock, Comprehensive Organic Transformations, 2nd ed.,
Wiley-VCH, Weinheim, Germany, 2010.
[3] T. Takeda, Modern Carbonyl Olefination, Wiley-VCH,
Weinheim, Germany, 2004.
[4] a) G. Wittig, U. Schöllkopf, Chem. Ber. 1954, 87, 1318–1330;
b) G. Wittig, G. Geissler, Justus Liebigs Ann. Chem. 1953, 580,
44–57.
[5] D. J. Peterson, J. Org. Chem. 1968, 33, 780–784.
[6] a) M. Julia, J.-M. Paris, Tetrahedron Lett. 1973, 14, 4833–4836;
b) P. J. Kocienski, B. Lythgoe, S. Ruston, J. Chem. Soc. Perkin
Trans. 1 1978, 829–834.
[7] a) K. C. Nicolaou, M. W. Härter, J. L. Gunzner, A. Nadin, Lie-
bigs Ann./Recueil 1997, 1283–1301; b) B. E. Maryanoff, A. B.
Reitz, Chem. Rev. 1989, 89, 863–927; c) P. J. Murphy, S. E. Lee,
J. Chem. Soc. Perkin Trans. 1 1999, 3049–3066; d) P. A. Byrne,
D. G. Gilheany, Chem. Soc. Rev. 2013, 42, 6670–6696.
[8] a) H. Ernst, Pure Appl. Chem. 2002, 74, 2213–2226; b) C.
Mercier, P. Chabardes, Pure Appl. Chem. 1994, 66, 1509–1518.
[9] a) M. Edmonds, A. Abell, in: Modern Carbonyl Olefination
(Ed.: T. Takeda), Wiley-VCH, Weinheim, Germany, 2004, p.
1–17; b) M. K. Edmonds, A. D. Abell, in: Organophosphorus
Methyl (E)-5-(5-Methylfur-2-yl)hex-2-enoate (5f): According to the
GP, 3-(5-methylfur-2-yl)butylaldehyde (4f; 224 mg, 1.47 mmol),
methyl bromoacetate (2a; 270 mg, 1.76 mmol), Bu3P=O (48 mg,
0.22 mmol, 15 mol-%), PhSiH3 (239 mg, 2.21 mmol), and 1,2-ep-
oxybutane (212 mg, 2.94 mmol) in dioxane (0.7 mL) were con-
verted for 2 h. Purification (SiO2, CH/EtOAc, 20:1) gave 5f
1
(239 mg, 1.15 mmol, 78%, E/Z = 89:11) as a yellow oil. H NMR
(300 MHz, CDCl3): δ = 1.25 (d, J = 7.0 Hz, 3 H, CH3), 2.26 (s, 3
H, CH3), 2.33–2.44 (m, 1 H, CH2), 2.55–2.65 (m, 1 H, CH2), 2.89–
3.00 (m, 1 H, CH), 3.73 (s, 3 H, CH3), 5.83–5.88 (m, 3 H), 6.87–
6.97 (m, 1 H, CH) ppm. 13C NMR (75 MHz, CDCl3): δ = 13.41
(CH3), 18.51 (CH3), 32.33 (CH), 38.22 (CH2), 51.31 (CH3), 104.62
(CH), 105.64 (CH), 122.41 (CH), 147.06 (CH), 150.36 (C), 156.95
(C), 166.78 (C=O) ppm. MS (EI, 70 eV): m/z (%) = 208 (4) [M]+,
109 (100) [M – C H CO Me]+. IR (ATR): ν = 2951 (w), 1721 (vs),
˜
3
4
2
1657 (m), 1613 (w), 1566 (w), 1436 (m), 1270 (m), 1216 (s), 1164
(vs), 1112 (m), 1019 (s), 957 (m), 940 (m), 780 (s), 720 (m) cm–1.
C12H16O3 (208.26): calcd. C 69.21, H 7.74; found C 69.19, H 7.65.
Methyl (E)-4-Phenylbut-2-enoate (5g):[52] According to the GP, 3-
phenylethanal (4g; 173 mg, 1.44 mmol), methyl bromoacetate (2a;
264 mg, 1.73 mmol), Bu3P=O (47 mg, 0.22 mmol, 15 mol-%),
PhSiH3 (234 mg, 2.16 mmol), and 1,2-epoxybutane (208 mg,
2.88 mmol) in dioxane (0.7 mL) were converted for 2 h. Purification
(SiO2, CH/EtOAc, 20:1) gave a mixture of 5g (107 mg, 42%, E/Z
= 94:6) and methyl 4-phenylbut-3-enoate (6 mg, 3%) as a yellowish
1
oil. Data for 5g: H NMR (300 MHz, CDCl3): δ = 3.54 (dd, J =
6.8, J = 1.5 Hz, 2 H, CH2), 3.73 (s, 3 H, CH3), 5.84 (dt, J = 15.6,
J = 1.6 Hz, 1 H, CH), 7.08–7.36 (m, 6 H) ppm. 13C NMR
Eur. J. Org. Chem. 2015, 4532–4543
© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
4541

M. Hoffmann, S. Deshmukh, T. Werner
FULL PAPER
Reagents (Ed.: P. J. Murphy), Oxford Unversity Press, Oxford,
UK, 2004, p. 99–127; c) O. I. Kolodiazhnyi, Phosphorus Ylides,
Wiley-VCH, Weinheim, Germany, 2007, p. 359–538.
a) H. A. van Kalkeren, A. L. Blom, F. P. J. T. Rutjes, M. A. J.
Huijbregts, Green Chem. 2013, 15, 1255–1263; b) H. A.
van Kalkeren, F. L. van Delft, F. P. J. T. Rutjes, ChemSusChem
2013, 6, 1615–1624.
a) M. G. Russell, S. Warren, Tetrahedron Lett. 1998, 39, 7995–
7998; b) D. Hermeling, R. Hugo, H. Siegel, BASF, Germany,
US5892121, 1999; c) M. G. Russell, S. Warren, J. Chem. Soc.
Perkin Trans. 1 2000, 505–513; d) B. H. Lipshutz, P. A.
Blomgren, Org. Lett. 2001, 3, 1869–1871; e) J. Westman, Org.
Lett. 2001, 3, 3745–3747; f) S. Dandapani, D. P. Curran, Tetra-
hedron 2002, 58, 3855–3864; g) P. S.-W. Leung, Y. Teng, P. H.
Toy, Synlett 2010, 1997–2001; h) P. A. Byrne, K. V. Rajendran,
J. Muldoon, D. G. Gilheany, Org. Biomol. Chem. 2012, 10,
3531–3537.
a) H. Pommer, Angew. Chem. Int. Ed. Engl. 1977, 16, 423–429;
Angew. Chem. 1977, 89, 437–443; b) T. Imamoto, T. Takeyama,
T. Kusumoto, Chem. Lett. 1985, 14, 1491–1492; c) G. Laven,
M. Kullberg, Chromafora Ab, Sweden, WO2011123037 2011.
a) L. Shi, W. Wang, Y. Wang, Y. Huang, J. Org. Chem. 1989,
54, 2027–2028; b) P. Cao, C.-Y. Li, Y.-B. Kang, Z. Xie, X.-L.
Sun, Y. Tang, J. Org. Chem. 2007, 72, 6628–6630; c) P. Wang,
C.-R. Liu, X.-L. Sun, S.-S. Chen, J.-F. Li, Z. Xie, Y. Tang,
Chem. Commun. 2012, 48, 290–292.
a) X. Huang, L. Xie, H. Wu, Tetrahedron Lett. 1987, 28, 801–
802; b) Y.-Z. Huang, L.-L. Shi, S.-W. Li, X.-Q. Wen, J. Chem.
Soc. Perkin Trans. 1 1989, 2397–2399; c) Z.-Z. Huang, S. Ye,
W. Xia, Y.-H. Yu, Y. Tang, J. Org. Chem. 2002, 67, 3096–3103;
d) K. Li, L. Ran, Y.-H. Yu, Y. Tang, J. Org. Chem. 2004, 69,
3986–3989.
Li, L.-Q. Lu, S. Das, S. Pisiewicz, K. Junge, M. Beller, J. Am.
Chem. Soc. 2012, 134, 18325–18329.
[22]
a) J. An, R. M. Denton, T. H. Lambert, E. D. Nacsa, Org. Bio-
mol. Chem. 2014, 12, 2993–3003; b) S. P. Marsden, Nat. Chem.
2009, 1, 685–687; c) H. A. van Kalkeren, J. J. Bruins, F. P. J. T.
Rutjes, F. L. van Delft, Adv. Synth. Catal. 2012, 354, 1417–
1421; d) H. A. van Kalkeren, C. te Grotenhuis, F. S. Haasjes,
C. A. Hommersom, F. P. J. T. Rutjes, F. L. van Delft, Eur. J.
Org. Chem. 2013, 7059–7066; e) H. A. van Kalkeren,
S. H. A. M. Leenders, C. R. A. Hommersom, F. P. J. T. Rutjes,
F. L. van Delft, Chem. Eur. J. 2011, 17, 11290–11295; f) A. D.
Kosal, E. E. Wilson, B. L. Ashfeld, Angew. Chem. Int. Ed.
2012, 51, 12036–12040; Angew. Chem. 2012, 124, 12202–12206.
[10]
[11]
[23] a) T. Werner, Adv. Synth. Catal. 2009, 351, 1469–1481; b) T.
Werner, A. M. Riahi, H. Schramm, Synthesis 2011, 3482–3490;
c) T. Werner, H. Büttner, ChemSusChem 2014, 7, 3268–3271;
d) T. Werner, M. Hoffmann, S. Deshmukh, Eur. J. Org. Chem.
2014, 6873–6876; e) T. Werner, M. Hoffmann, S. Deshmukh,
Eur. J. Org. Chem. 2014, 6630–6633.
[12]
[13]
[24] G. Keglevich, T. Kovács, F. Csatlós, Heteroatom Chem. 2014,
DOI: 10.1002/hc.21249.
[25] a) T. Werner, N. Tenhumberg, J. CO2 Util. 2014, 7, 39–45; b)
T. Werner, N. Tenhumberg, H. Büttner, ChemCatChem 2014,
6, 3493–3500.
[26] D. O. Jang, Synth. Commun. 1997, 27, 1023–1027.
[27] I. S. Kim, G. R. Dong, Y. H. Jung, J. Org. Chem. 2007, 72,
5424–5426.
[28] a) R. Imashiro, M. Seki, J. Org. Chem. 2004, 69, 4216–4226;
b) D. Mingji, B. Liang, C. Wang, Z. You, J. Xiang, G. Dong,
J. Chen, Z. Yang, Adv. Synth. Catal. 2004, 346, 1669–1673.
[29] J. Ruan, X. Li, O. Saidi, J. Xiao, J. Am. Chem. Soc. 2008, 130,
2424–2425.
[14]
[30]
[31]
B. Cooney, D. Happer, Aust. J. Chem. 1987, 40, 1537–1544.
T. L. Gilchrist, C. W. Rees, D. Tuddenham, J. Chem. Soc. Per-
kin Trans. 1 1981, 3214–3220.
M. Dai, B. Liang, C. Wang, J. Chen, Z. Yang, Org. Lett. 2003,
6, 221–224.
[15]
[16]
Y. Liao, Y.-Z. Huang, Tetrahedron Lett. 1990, 31, 5897–5900.
st
J. A. Kerr, in: CRC Handbook of Chemistry and Physics, 81
ed. (Ed.: D. R. Lide), Boca Raton, 2000.
[32]
[33]
[17]
a) C. J. O’Brien, J. L. Tellez, Z. S. Nixon, L. J. Kang, A. L. Car-
ter, S. R. Kunkel, K. C. Przeworski, G. A. Chass, Angew. Chem.
Int. Ed. 2009, 48, 6836–6839; Angew. Chem. 2009, 121, 6968–
6971; b) C. J. O’Brien, F. Lavigne, E. E. Coyle, A. J. Holohan,
B. J. Doonan, Chem. Eur. J. 2013, 19, 5854–5858; c) C. J.
O’Brien, Z. S. Nixon, A. J. Holohan, S. R. Kunkel, J. L. Tellez,
B. J. Doonan, E. E. Coyle, F. Lavigne, L. J. Kang, K. C.
Przeworski, Chem. Eur. J. 2013, 19, 15281–15289; d) E. E. Co-
yle, B. J. Doonan, A. J. Holohan, K. A. Walsh, F. Lavigne,
E. H. Krenske, C. J. O’Brien, Angew. Chem. Int. Ed. 2014, 53,
12907–12911; Angew. Chem. 2014, 126, 13121–13125.
a) P. D. Henson, K. Naumann, K. Mislow, J. Am. Chem. Soc.
1969, 91, 5645–5646; b) T. Imamoto, T. Takeyama, T. Kusum-
oto, Chem. Lett. 1985, 1491–1492; c) T. Imamoto, T. Oshiki,
T. Onozawa, T. Kusumoto, K. Sato, J. Am. Chem. Soc. 1990,
112, 5244–5252; d) T. Imamoto, S.-i. Kikuchi, T. Miura, Y.
Wada, Org. Lett. 2001, 3, 87–90; e) R. M. Hiney, L. J. Higham,
H. Müller-Bunz, D. G. Gilheany, Angew. Chem. Int. Ed. 2006,
45, 7248–7251; Angew. Chem. 2006, 118, 7406–7409.
a) M. Stankevic, K. M. Pietrusiewicz, Synlett 2003, 7, 1012–
1016; b) K. V. Rajendran, D. G. Gilheany, Chem. Commun.
2012, 48, 817–819.
C. A. Busacca, R. Raju, N. Grinberg, N. Haddad, P. James-
Jones, H. Lee, J. C. Lorenz, A. Saha, C. H. Senanayake, J. Org.
Chem. 2008, 73, 1524–1531.
a) K. L. Marsi, J. Org. Chem. 1974, 39, 265–267; b) T. Coumbe,
N. J. Lawrence, F. Muhammad, Tetrahedron Lett. 1994, 35,
625–628; c) N. J. Lawrence, M. D. Drew, S. M. Bushell, J.
Chem. Soc. Perkin Trans. 1 1999, 3381–3391; d) A. Favre-Régu-
illon, J. Mohamad, G. Mignani, G. Docherty, M. Lemaire,
Synlett 2007, 10, 1545–1548; e) C. Petit, A. Favre-Reguillon, B.
Albela, L. Bonneviot, G. Mignani, M. Lemaire, Organometal-
lics 2009, 28, 6379–6382; f) C. Petit, A. Favre-Reguillon, G.
Mignani, M. Lemaire, Green Chem. 2010, 12, 326–330; g) Y.
a) K. Ohe, H. Takahashi, S. Uemura, N. Sugita, J. Org. Chem.
1987, 52, 4859–4863; b) G. Xie, P. Chellan, J. Mao, K. Chibale,
G. S. Smith, Adv. Synth. Catal. 2010, 352, 1641–1647.
S. Karthikeyan, V. Ramamurthy, J. Org. Chem. 2007, 72, 452–
458.
a) D. A. R. Happer, B. E. Steenson, J. Chem. Soc. Perkin Trans.
2 1988, 19–24; b) S. Kojima, T. Fukuzaki, A. Yamakawa, Y.
Murai, Org. Lett. 2004, 6, 3917–3920.
N. G. Anthony, D. Breen, J. Clarke, G. Donoghue, A. J. Drum-
mond, E. M. Ellis, C. G. Gemmell, J.-J. Helesbeux, I. S. Hunter,
A. I. Khalaf, S. P. Mackay, J. A. Parkinson, C. J. Suckling,
R. D. Waigh, J. Med. Chem. 2007, 50, 6116–6125.
G. Hilt, C. Hengst, J. Org. Chem. 2007, 72, 7337–7342.
a) J. Muhuhi, M. R. Spaller, J. Org. Chem. 2006, 71, 5515–
5526; b) B. Schmidt, F. Hölter, R. Berger, S. Jessel, Adv. Synth.
Catal. 2010, 352, 2463–2473.
J. G. Walsh, P. J. Furlong, L. A. Byrne, D. G. Gilheany, Tetra-
hedron 1999, 55, 11519–11536.
V. R. Chintareddy, A. Ellern, J. G. Verkade, J. Org. Chem. 2010,
75, 7166–7174.
P. Sun, Y. Zhu, H. Yang, H. Yan, L. Lu, X. Zhang, J. Mao,
Org. Biomol. Chem. 2012, 10, 4512–4515.
a) S. Nakamura, T. Hayakawa, T. Nishi, Y. Watanabe, T. Toru,
Tetrahedron 2001, 57, 6703–6711; b) A.-Y. Peng, B.-T. Chen, Z.
Wang, B. Wang, X.-B. Mo, Y.-Y. Wang, P.-J. Chen, J. Fluorine
Chem. 2011, 132, 982–986.
[34]
[35]
[36]
[18]
[37]
[38]
[39]
[40]
[41]
[42]
[19]
[20]
[21]
[43]
[44]
[45]
E. Kim, M. Koh, B. J. Lim, S. B. Park, J. Am. Chem. Soc. 2011,
133, 6642–6649.
E. N. Jacobsen, L. Deng, Y. Furukawa, L. E. Martínez, Tetra-
hedron 1994, 50, 4323–4334.
a) F. P. Touchard, Tetrahedron Lett. 2004, 45, 5519–5523; b)
S. W. Youn, B. S. Kim, A. R. Jagdale, J. Am. Chem. Soc. 2012,
134, 11308–11311.
4542
www.eurjoc.org
© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2015, 4532–4543

The Microwave-Assisted Catalytic Wittig Reaction
[46] F. D. Lewis, D. K. Howard, J. D. Oxman, A. L. Upthagrove, [51] a) D. F. Taber, R. J. Herr, S. K. Pack, J. M. Geremia, J. Org.
S. L. Quillen, J. Am. Chem. Soc. 1986, 108, 5964–5968.
[47] A. El-Batta, C. Jiang, W. Zhao, R. Anness, A. L. Cooksy, M.
Bergdahl, J. Org. Chem. 2007, 72, 5244–5259.
[48] S. Wei, X.-G. Wei, X. Su, J. You, Y. Ren, Chem. Eur. J. 2011,
17, 5965–5971.
[49] T. J. Donohoe, J. A. Basutto, J. F. Bower, A. Rathi, Org. Lett.
2011, 13, 1036–1039.
Chem. 1996, 61, 2908–2910; b) D. D. Kim, S. J. Lee, P. Beak,
J. Org. Chem. 2005, 70, 5376–5386.
[52] a) K. C. Nicolaou, E. W. Yue, S. La Greca, A. Nadin, Z. Yang,
J. E. Leresche, T. Tsuri, Y. Naniwa, F. de Riccardis, Chem. Eur.
J. 1995, 1, 467–494; b) A. Fürstner, R. Martin, H. Krause, G.
Seidel, R. Goddard, C. W. Lehmann, J. Am. Chem. Soc. 2008,
130, 8773–8787.
[50] a) S.-Y. Wang, S.-J. Ji, T.-P. Loh, J. Am. Chem. Soc. 2007, 129, [53] K. Tsutsumi, T. Inaba, T. Tanaka, Japan Tabacco Inc., Japan,
276–277; b) T. D. W. Claridge, S. G. Davies, J. A. Lee, R. L.
Nicholson, P. M. Roberts, A. J. Russell, A. D. Smith, S. M.
Toms, Org. Lett. 2008, 10, 5437–5440.
WO199629307, 1996.
Received: March 6, 2015
Published Online: June 10, 2015
Eur. J. Org. Chem. 2015, 4532–4543
© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
4543