Pd(0)-catalyzed couplings using bromide and chloride derivatives of Baylis-Hillman adducts with triarylbismuths as atom-efficient multi-coupling nucleophiles

Article abstract of DOI:10.1016/j.tet.2010.03.020

Bromide and chloride derivatives of Baylis-Hillman adducts have been demonstrated to react efficiently with triarylbismuths affording allylic arylated products in high yields under palladium-catalyzed conditions. Triarylbismuths have been employed in sub-stoichiometric amounts as multi-coupling and atom-efficient nucleophiles in these reactions. The reactivity of both allylic bromides and chlorides was found to be facile and equally efficient in couplings with triarylbismuths.

Full text of DOI:10.1016/j.tet.2010.03.020

Tetrahedron 66 (2010) 3623–3632
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Tetrahedron
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Pd(0)-catalyzed couplings using bromide and chloride derivatives
of Baylis–Hillman adducts with triarylbismuths as atom-efficient
multi-coupling nucleophiles
*
Maddali L.N. Rao , Debasis Banerjee, Ritesh J. Dhanorkar
Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
a r t i c l e i n f o
a b s t r a c t
Article history:
Bromide and chloride derivatives of Baylis–Hillman adducts have been demonstrated to react efficiently
with triarylbismuths affording allylic arylated products in high yields under palladium-catalyzed con-
ditions. Triarylbismuths have been employed in sub-stoichiometric amounts as multi-coupling and
atom-efficient nucleophiles in these reactions. The reactivity of both allylic bromides and chlorides was
found to be facile and equally efficient in couplings with triarylbismuths.
Received 2 February 2010
Received in revised form 28 February 2010
Accepted 5 March 2010
Available online 11 March 2010
Ó 2010 Elsevier Ltd. All rights reserved.
Keywords:
Allylic bromides and chlorides
Baylis–Hillman adducts
Cross-coupling
Palladium
Triarylbismuths
1. Introduction
The Baylis–Hillman reaction and its adducts provides a unique
functional platform useful for
a variety of synthetic trans-
Bismuth compounds are environment friendly as they are non-
toxic and have been used even in medicinal applications.1 Bismuth
reagents have also been utilized for many synthetic trans-
formations in organic chemistry.2 The chemistry of organobismuth
compounds is of special interest as these are useful for carbon–
carbon and carbon–heteroatom bond formations.2a There is
a growing interest in the utilization of these compounds in several
ways with promising novel reactivities.3,4 Here, triarylbismuths
needs a special mention as these compounds are useful as atom-
efficient multi-coupling reagents in C–C coupling methods.5–7 The
multi-coupling ability of triarylbismuths reacting with three
equivalents of organic electrophiles under metal catalyzed condi-
tions is of interest to us, as this allows the development of atom-
economic coupling reactions. Hence, we have been involved in
the development of new atom-efficient or -economic C–C coupling
reactions using triarylbismuths as multi-coupling organometallic
nucleophiles.6 Need for the development of multi-coupling
organometallic reagents for C–C bonds formation is due to their
importance in the chemical industry for pharmaceutical and
material applications.8
formations.9 The pioneering work of Basavaiah et al.10 and other
groups have taken this reaction to a newer heights and is a testi-
mony for its uniqueness to generate multi-functional skeletons in
synthetic organic chemistry.11,12 In the present context, Baylis–
Hillman adducts have recently been involved in the coupling
reactions with organometallic reagents such as organoboron,
organosilicon and bimetallic reagents.13 However, the reactivity
using other derivatives of Baylis–Hillman adducts are less studied
in coupling reactions. Although triarylbismuths coupling with
allylic bromides14 and acetates6d are known, the study of halide
derivatives15 of Baylis–Hillman adducts is of special importance
from the view point of its reactivity and additional functional
features. With this aim we have carried out the present study using
bromide and chloride derivatives of Baylis–Hillman adducts with
triarylbismuths under palladium-catalyzed conditions.
2. Results and discussion
The desired bromide and chloride derivatives of Baylis–Hillman
adduct have been prepared according to known procedures12
(Scheme 1).
These transformations afforded the corresponding bromide and
chloride derivatives cleanly. So, with a view to study the reactivity
of these substrates as organic electrophiles the following efforts
* Corresponding author. Tel./fax: þ91 512 259 7532; e-mail address: maddali@
iitk.ac.in.
0040-4020/$ – see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2010.03.020

3624
M.L.N. Rao et al. / Tetrahedron 66 (2010) 3623–3632
OH O
O
ref. 12
+
RCHO
R
OMe
OMe
R=alkyl, aryl,
heteroaryl
Table 2
Couplings with different triarylbismuthsa–d
Conditions:
(i) or (ii)
ref. 16
O
O
Pd2(dba)3
OMe
(0.09 equiv)
Bi
OMe
(i) for bromides: 33% HBr/AcOH,
H2SO4 (cat.), rt, 16 h, 51-68%
+
Cs2CO3 (1 equiv)
DMA, 90 oC, 1 h
3
R
Br
R
3
O
(1 equiv)
(3.3 equiv)
(3 equiv)
(ii) for chlorides: HCl, H2SO4 (cat.)
rt, 36 h, 48-75%
R
OMe
X
Entry
BiAr3
Product
Yield (%)
73
Scheme 1. Bromide and chloride derivatives of Baylis–Hillman adducts.
O
OMe
Bi
1
2
3
have been carried out under palladium catalysis. Firstly, the cou-
pling study of bromide (1) derived from Baylis–Hillman adduct was
employed with triphenylbismuth (2) under different catalytic
conditions to check its efficacy to afford the arylated product 3.10 as
summarized in Table 1.
3.1
O
O
OMe
Me
Bi
Me
90
91
3.2
3
Table 1
Me
Screening conditions with bromidea–c
OMe
Me
3
Bi
O
3.3
O
3
[Pd]
Bi
OMe
OMe
Ph-Ph
+
+
3
O
O
O2N
Br
O2N
4
( )
OMe
OMe
(1 equiv)
(3 equiv)
(3.10)
(3.3 equiv)
Bi
OMe
4
75
3.4
2
( )
1
( )
3
Entry
Catalyst & conditions
3.10 (%)
4 (%)
OMe
1
2
3
4
5
6
7
8
Pd2(dba)3, K3PO4 (1)/KI(2), DMF
Pd(PPh3)4, K3PO4 (1)/KI(2), DMF
39
20
28
42
54
57
54
62
29
29
34
55
58
30
21
13
21
21
53
15
10
14
27
9
OMe
OMe
5
6
85
73
Bi
Bi
PdCl2(PPh3)2, K3PO4 (1)/KI(2), DMF
Pd2(dba)3, K2CO3(1), DMF
Pd2(dba)3, Na2CO3(1), DMF
Pd2(dba)3, Cs2CO3(1), DMF
Pd2(dba)3, Na2CO3(2), DMF
Pd2(dba)3, Cs2CO3(2), DMF
Pd2(dba)3, Cs2CO3(1), CH3CN
Pd2(dba)3, Cs2CO3(1), DCE
Pd2(dba)3, Cs2CO3(1), DMA
Pd2(dba)3, Cs2CO3(1), DMA
Pd2(dba)3, Cs2CO3(1), DMA
Pd2(dba)3, Cs2CO3(1), DMA
Pd2(dba)3, Cs2CO3(1)/PPh3, DMA
Pd2(dba)3, No Base, DMA
3.5
3.6
3
O
OMe
OEt
OMe
OEt
F
3
9
10
11
12
13
14
15
16
17
79(75)
68d
50e
68f
O
Bi
7
8
79
85
3.7
3
23d
55
70
16
8
F
No catalyst, Cs2CO3(1), DMA
4
O
a
Conditions: BiPh3 (1 equiv), bromide (3.3 equiv), base (1–2 equiv), additive
(2 equiv), palladium catalyst (0.09 equiv), solvent (3 mL), 90 ꢀC, 1 h.
OMe
Cl
Bi
Cl
3.8
3.9
b
3
Conversions are based on GC analysis of the crude reaction mixture.
c
Isolated yield is given in parenthesis.
d
Reaction at 60 ꢀC.
e
Reaction at 40 ꢀC.
O
f
Reaction for 2 h.
Cl
OMe
9
70
Bi
3
The different palladium catalysts screened for the reaction
showed poor coupling reactivity to furnish arylation product 3.10
under the conditions studied with K3PO4 base (entries 1–3). In the
absence of effective cross-coupling, triphenylbismuth delivered
homo-coupling biphenyl in higher amounts. This homo-coupling
reactivity of triarylbismuths is well established using palladium
catalysis.7a As Pd2(dba)3 catalyst demonstrated relative better
performance among the catalysts studied, this has been further
screened with different bases. These reactions provided moderate
results with K2CO3, Na2CO3 and Cs2CO3 bases (entries 4–6).
However, relative better performance was observed with Cs2CO3 as
base both in terms of higher cross-coupling and lower
homo-coupling conversion (entry 6). Further increase in base
Cl
a
Reaction conditions: methyl-(2-bromomethyl)-3-phenylacrylate (0.825 mmol,
3.3 equiv), BiAr3 (0.25 mmol, 1 equiv), Cs2CO3 (0.25 mmol, 1 equiv), Pd2(dba)3
(0.0225 mmol, 0.09 equiv) and DMA (3 mL), 90 ꢀC, 1 h.
b
Isolated yields calculated considering all three aryl groups of triarylbismuths for
coupling. Thus, 0.75 mmol of the product correspond to 100% yield.
c
In general, homo-coupled bi-aryls from triarylbismuths formed in all the re-
actions and the amount varied with respect to the degree of the cross-coupling
product.
d
All products were characterized by 1H NMR, 13C NMR, IR and ESI-HRMS data and
in comparison with literature data.

M.L.N. Rao et al. / Tetrahedron 66 (2010) 3623–3632
3625
equivalents also did not improve the product conversion consid-
erably (entries 7 and 8). Additionally, the influence of different
solvents on the coupling was investigated with Cs2CO3 base (entries
9–11). During this study, N,N-dimethylacetamide (DMA) solvent
was found to be more effective with increased coupling up to 75%
yield of 3.10 (entry 11). The reaction was also studied at different
temperature conditions. This has revealed that the coupling is not
efficient under lower temperature conditions (entries 12 and 13).
Additional time also did not improve the desired product formation
(entry 14).
So, the coupling reaction carried out with 90 ꢀC was found to be
optimum temperature condition to obtain higher coupling yield
(entry 11). Addition of triphenylphosphine as ligand resulted
inferior conversion (entry 15). Further control reactions carried out
without base and catalyst delivered poor results (entries16 and 17)
indicating their effective role to furnish high coupling yield
(entry 11).
With the above investigation it was found that the cross-
coupling is more effective using Pd2(dba)3 catalyst and Cs2CO3
base in DMA solvent at 90 ꢀC to furnish high yield of the product
3.10 in short reaction time. It is to be noted that the overall reaction
involves the formation of three C–C bonds from triphenylbismuth
in reaction with three equivalents of allylic bromide. This indicates
the facile of reactivity of triphenylbismuth in the arylation of
bromide derived from Baylis–Hillman adduct under the established
protocol.
To expand the potential of this study, various triarylbismuths
have been employed in the allylic arylation studies as given in
Table 2. The electronically divergent triarylbismuths containing
both electron-withdrawing and -donating groups performed
efficiently giving high yields of arylated coupling products. Other
way, this coupling reaction provided an opportunity for further
functionalization of bromide derivative of Baylis–Hillman adduct
with a variety of functionalized aryl substituents. Thus the coupling
furnished various functionalized tri-substituted alkenes very
efficiently.
additional amount of base (entries 2 and 3). However, when the
amount of base was increased to three equivalents, the reaction
provided arylated product up to 71% yield (entry 4). Then, it was
decided to screen the reaction in different solvents and bases to
affect further improvement in product yield. Reactions with
different bases in DMA solvent were found to be ineffective to
give high amount of the product (entries 7–9). Additional
study with K3PO4 base in different solvents also did not furnish
any further improvements (entries 10–13). A control reaction
without base afforded poor conversion to cross-coupling product
(entry 14). Another reaction without catalyst also furnished
lower conversion (entry 15). From the above investigation,
we found that the protocol with Pd2(dba)3 catalyst and in the
presence of 3 equiv of Cs2CO3 in DMA solvent as an ideal
combination to furnish high yield of coupling product 3.10
(entry 4).
Hence, the coupling reactions of various Baylis–Hillman ad-
ducts derived chlorides have been studied with triarylbismuths
under the optimized protocol. These results are given in Table 5.
The reactivity of chloride derivatives was found to be equally
efficient with different triarylbismuths giving high yields of the
arylated products. These couplings of chlorides were almost
comparable to that found with corresponding bromides in giving
high yields of the products with triarylbismuths under the
established conditions. Earlier couplings of allylic bromides with
triarylbismuths involved longer reaction times even under
refluxing conditions in the presence of palladium catalyst.14b
Whereas, in this study bromide and chlorides derivatives of
Baylis–Hillman adducts reacted very well in a facile manner and
exhibited superior coupling reactivity with high yields in shorter
reaction times. In addition, the coupling reactivity of these adducts
is similar to that observed with allylic acetates under palladium-
catalyzed conditions.6d
The mechanistic aspects of this reaction could be similar to the
earlier known couplings as proposed in Scheme 2.8a,13c The oxida-
tive addition of allylic halide (either bromide or chloride) would
To further explore the scope of this reaction, various other
bromides derived from Baylis–Hillman adducts were subjected to
cross-coupling with triarylbismuths under the established pro-
tocol. These results are summarized in Table 3. The couplings
carried out with a variety of functionalized bromides underwent
facile coupling to the corresponding arylated products. Overall,
an efficient reactivity of divergent triarylbismuths was estab-
lished with a variety of bromides in this study. In all these re-
actions each triarylbismuth was coupled with 3 equiv of
bromides furnishing 3 equiv of the corresponding arylated
products. Further, all the reactions were completed in short re-
action time of 1 h despite the involvement of three couplings
from triarylbismuths. This indicates the high reactivity of triar-
ylbismuths as atom-efficient multi-coupling nucleophiles in
these couplings.
lead to the formation of p-allyl palladium intermediate. This in turn
involves with BiAr3 in transmetalation step to form arylallyl–pal-
ladium intermediate. Reductive elimination of this intermediate is
expected to give the arylated product. As triarylbismuths are
involved as multi-coupling nucleophiles in these couplings, par-
ticipation of either Ar2BiX or ArBiX2 is essential in transmetalation
step for the effective utilization of three aryl groups. Alternative
regeneration of triarylbismuths via disproportion of arylbismuth
halides in situ during the reaction is another possibility.7a The role
of base in the reaction is expected to activate Bi–C bond of aryl-
bismuths for facile transfer of aryl group during transmetalation
step. Overall, the novel and efficient couplings of triarylbismuths
with three equivalents of either bromide or chloride derivatives of
Baylis–Hillman adducts were realized under the established
conditions.
It was fascinating to realize the facile reactivity of bromides
derived from Baylis–Hillman adducts with triarylbismuths under
the established palladium catalysis. This encouraged us to extend
this study with chlorides of Baylis–Hillman adducts as these com-
pounds are also promising and potential organic electrophiles
(Table 4).
The coupling reaction of chloride derivative of Baylis–Hillman
adduct (5) was carried out under the established protocol for
bromide. This has provided only moderate conversion to product
3.10 (entry 1). As the optimized condition for bromide couplings
found to be ineffective for corresponding chloride coupling,
a brief screening has been carried out to find the right combi-
nation to improve the yield of arylation product 3.10. As given in
the Table 4, the reaction failed to provide better conversion to the
desired product either with increase in reaction time or with
3. Conclusions
In summary, an efficient palladium-catalyzed conditions for
the cross-coupling of triarylbismuths with bromide and chloride
derivatives of Baylis–Hillman adducts have been developed.
These protocols furnished high yields of arylated products in
short reaction time. Involvement of triarylbismuths compounds
in sub-stoichiometric amounts as multi-coupling organometallic
nucleophiles is promising from the view point of atom-economic
or atom-efficient couplings involving organometallic reagents.
The study also disclosed the novel reactivity of both bromide and
chloride derivatives of Baylis–Hillman adducts for C–C bond
formations under palladium catalysis using triarylbismuth
reagents.

3626
M.L.N. Rao et al. / Tetrahedron 66 (2010) 3623–3632
Table 3
Couplings with different bromides and triarylbismuthsa–d
O
O
Pd2(dba)3 (0.09 equiv)
OMe
OMe
R1
Bi
+
Cs2CO3 (1 equiv)
Br
R2
3
R2
3
DMA, 90 oC, 1 h
R1
(1 equiv)
(3.3 equiv)
(3 equiv)
Entry
1
BiAr3
Bromide
Product
Yield (%)
75
O
Bi
OMe
3
O2N
O2N
3.10
O
OMe
Me
Bi
Me
2
3
4
70
80
63
3
3.11
3.12
O
Me
OMe
Me
Bi
O2N
O2N
3
O
OMe
OMe
Bi
OMe
3
3.13
3.14
O
OMe
Br
O
O2N
OMe
OEt
OMe
5
6
60
65
Bi
OEt
F
O2N
3
O
Bi
O2N
3
3.15
F
O
OMe
Cl
Bi
Cl
7
60
60
80
81
78
O2N
3
3.16
O
Cl
OMe
Cl
8
Bi
O2N
Cl
3
3.17
3.18
O
Me
OMe
Me
9
Bi
Bi
3
O
OMe
O
Cl
Br
OMe
OMe
OMe
10
11
Cl
3
3.19
O
OMe
Me
O
Bi
Bi
3.20
3
Me
O
O
OMe
O
OMe
OMe
Br
O
12
82
3.21
3
OMe

M.L.N. Rao et al. / Tetrahedron 66 (2010) 3623–3632
3627
Table 3 (continued)
Entry
BiAr3
Bromide
Product
Yield (%)
CN
Bi
Me
13
14
15
16
75
63
72
74
3.22
3
CN
Br
Me
Me
Me
CN
R
Bi
3.23
3
Me
Bi
Me
MeOOC
3.24
3
R
Me
R
Bi
MeOOC
Me
3
Br
3.25
MeOOC
R = n-butyl
R
OMe
17
75
Bi
MeOOC
OMe
3
3.26
a
Reaction conditions: bromide (0.825 mmol, 3.3 equiv), BiAr3 (0.25 mmol, 1 equiv), Cs2CO3 (0.25 mmol, 1 equiv), Pd2(dba)3 (0.0225 mmol, 0.09 equiv) and DMA (3 mL),
90 ꢀC, 1 h.
b
Isolated yields calculated considering all three aryl groups from triarylbismuths for coupling. Thus, 0.75 mmol of the product correspond to 100% yield.
In general, homo-coupled bi-aryls from triarylbismuths formed in all the reactions and the amount varied with respect to the degree of the cross-coupling product.
All products were characterized by 1H NMR, 13C NMR, IR and ESI-HRMS data and in comparison with literature data.
c
d
Triarylbismuth compounds were prepared following known
procedure.2a NMR spectra were recorded on JEOL–Lambda
Table 4
Screening conditions with chloridea–c
(400 MHz and 500 MHz) spectrometers with CDCl3 solvent and
TMS as an internal standard. HRMS was measured with Waters
ESI-QTOF instrument. IR spectra were recorded on a Bruker Vector
22 FT-IR spectrometer. Analysis of crude reaction mixture and
pure products were performed on Perkin Elmer (Clarus 500) Gas
Chromatograph. Silica gel (100–200 mesh) for column chroma-
tography and GF-254 silica gel (Merck) was used for TLC. All
the solvents were distilled using standard drying methods
prior to use. All the reactions were performed under nitrogen
atmosphere in an oven dried Schlenk tubes and using dry
solvents.
O
OMe
O
[Pd]
O2N
Bi
OMe
Ph-Ph
+
+
3
O2N
Cl
(4)
(3.3 equiv)
(1 equiv)
(3 equiv)
(3.10)
2
( )
(5)
Entry
Catalyst & conditions
3.10 (%)
4 (%)
1
2
3
4
5
6
7
8
Pd2(dba)3, Cs2CO3(1), DMA
Pd2(dba)3, Cs2CO3(1), DMA
Pd2(dba)3, Cs2CO3(2), DMA
Pd2(dba)3, Cs2CO3(3), DMA
Pd2(dba)3, Cs2CO3(3), DMF
Pd2(dba)3, Cs2CO3(3), NMP
Pd2(dba)3, K2CO3(3), DMA
Pd2(dba)3, Na2CO3(3), DMA
Pd2(dba)3, K3PO4(3), DMA
Pd2(dba)3, K3PO4(3), DMF
Pd2(dba)3, K3PO4(3), NMP
Pd2(dba)3, K3PO4(3), DMF
Pd2(dba)3, K3PO4(3), NMP
Pd2(dba)3, No Base, DMA
50
20
20
20
18
23
20
18
13
19
19
14
21
20
24
10
52d
55
74(71)
65(60)
66(58)
37
4.2. Representative procedure for cross-coupling of bromides
of Baylis–Hillman adducts with triarylbismuths
42
55
11
46
9
A hot-oven dried Schlenk tube was charged with methyl-
(2-bromomethyl)-3-phenylacrylate (0.825 mmol, 0.210 g) fol-
lowed by triphenylbismuth (0.25 mmol, 0.11 g), Cs2CO3
(0.25 mmol, 0.082 g), Pd2(dba)3 (0.0225 mmol, 0.0206 g) and DMA
(3 mL) solvent under nitrogen atmosphere. Then the contents
were stirred in an oil bath at 90 ꢀC for 1 h. After the reaction time,
contents were cooled, quenched with water (10 mL) and extracted
with ethyl acetate (3ꢁ15 mL). The combined organic extract was
washed with water (2ꢁ10 mL), brine (10 mL) and dried over
anhydrous MgSO4. The extract was concentrated under reduced
pressure to obtain the crude product mixture. This was purified on
silica gel by column chromatography (1% EtOAc/petroleum ether)
to afford 2-benzyl-3-phenylacrylic acid methyl ester (3.1) as col-
ourless oil (0.137 g, 73%). Isolated yield was calculated considering
all three aryl groups for couplings from triphenylbismuth. Thus,
0.75 mmol of the product correspond to 100% yield. The product
was identified by spectroscopic analysis and in comparison with
the literature data.
10
11
12
13
14
15
57d
45d
42
No Catalyst, Cs2CO3 (3), DMA
4
a
Conditions: BiPh3 (1 equiv), chloride (3.3 equiv), base (1–3 equiv), palladium
catalyst (0.09 equiv), solvent (3 mL), 90 ꢀC, 1 h.
b
Conversions are based on GC analysis of the crude reaction mixture with respect
to triphenylbismuth.
c
Isolated yield given in parenthesis.
For 2 h.
d
4. Experimental section
4.1. General
All Baylis–Hillman adducts and corresponding bromides/
chlorides were prepared according to literature procedures.16

3628
M.L.N. Rao et al. / Tetrahedron 66 (2010) 3623–3632
Table 5
Couplings with different chlorides and triarylbismuthsa–d
O
O
Pd2(dba)3 (0.09 equiv)
OMe
OMe
R1
Bi
+
Cs2CO3 (3 equiv)
DMA, 90 oC, 1 h
R2
3
Cl
R2
R1
3
(3.3 equiv)
(1 equiv)
(3 equiv)
Entry
1
BiAr3
Chloride
Product
Yield (%)
76
O
OMe
Bi
3
3.1
O
OMe
Me
Bi
Me
2
82
82
81
80
82
80
71
73
75
3
3.2
O
Me
OMe
3
Bi
3.3
3
Me
O
O
OMe
OMe
3
4
OMe
Bi
Bi
3.5
3.7
Cl
OMe
OMe
O
O
F
5
3
F
OMe
Bi
Cl
6
3
3.8
3.9
Cl
O
Cl
OMe
7
Bi
3
Cl
O
OMe
Bi
8
3
O2N
3.10
O
OMe
Me
Bi
Me
9
O2N
3
3.11
O
O
OMe
Cl
Me
3
OMe
Me
10
O2N
O2N
O2N
Bi
3.12
3.27
O
OMe
3
OMe
11
75
Bi
OMe
a
Reaction conditions: allylic chloride (0.825 mmol, 3.3 equiv), BiAr3 (0.25 mmol, 1 equiv), Cs2CO3 (0.75 mmol, 3 equiv), Pd2(dba)3 (0.0225 mmol, 0.09 equiv) and DMA
(3 mL), 90 ꢀC, 1 h.
b
Isolated yields calculated considering all three aryl groups from triarylbismuths for coupling. Thus, 0.75 mmol product correspond to 100% yield.
c
In general, homo-coupled bi-aryls from triarylbismuths formed in all the reactions and the amount varied with respect to the degree of the cross-coupling product.
d
All products were characterized by 1H NMR, 13C NMR, IR and ESI-HRMS data and in comparison with literature data.

M.L.N. Rao et al. / Tetrahedron 66 (2010) 3623–3632
3629
(500 MHz, CDCl3): 7.85 (s, 1H, C]CH), 7.21–7.30 (m, 5H, CHar), 7.10
(t, J¼7.55, 8.25 Hz, 1H, CHar), 6.93 (t, J¼8.60, 8.95 Hz, 3H, CHar), 3.84
(s, 2H, CH2), 3.67 (s, 3H, OCH3), 2.23 (s, 3H, CH3); dC NMR (125 MHz,
CDCl3): 168.65, 140.91, 139.20, 138.07, 135.29, 130.61, 129.18, 128.61,
128.53,126.88,124.81, 52.10, 33.01, 21.45; ESI(HRMS) (m/z) calcd for
C18H19O2, (MþH)þ 267.1385, found 267.1385.
R'
X
R
R'
Ar
R
Pd(0)
Oxidative
addition
Reductive
elimination
X = Br, Cl
4.4.4. 2-(4-Methoxybenzyl)-3-phenylacrylic acid methyl ester
(3.4)13a. The crude product was purified by column chromatog-
raphy using (2.5% ethyl acetate in petroleum ether) to give 3.4 as
colourless oil (158 mg, 75%); Rf (5% ethyl acetate in petroleum
ether) 0.55; IR (neat, cmꢂ1): 3000, 2950, 1714, 1511, 1439, 1247,
1033, 758; dH NMR (500 MHz, CDCl3): 7.82 (s, 1H, C]CH), 7.23–7.34
(m, 5H, CHar), 7.03 (d, J¼8.55 Hz, 2H, CHar), 6.75 (d, J¼8.95 Hz, 2H,
CHar), 3.81 (s, 2H, CH2), 3.69 (s, 3H, OCH3), 3.67 (s, 3H, OCH3); dC
NMR (125 MHz, CDCl3): 168.66, 157.92, 140.62, 135.30, 131.24,
130.98, 129.17, 128.81, 128.69, 128.53, 113.91, 55.18, 52.08, 32.20.
R'
R'
R
R
Pd
X
Pd
Ar
BiAr3
Transmetalation
BiAr2X
Scheme 2. Proposed mechanistic cycle.
4.4.5. 2-(3-Methoxybenzyl)-3-phenylacrylic acid methyl ester
(3.5). The crude product was purified by column chromatography
using (2% ethyl acetate inpetroleum ether) to give 3.5 as colourless oil
(179 mg, 85%); Rf (5% ethyl acetate in petroleum ether) 0.55; IR (neat,
cmꢂ1): 2999, 2949, 2836,1712,1601,1489,1436,1265,1203, 982, 826;
dH NMR (400 MHz, CDCl3): 7.96 (s,1H, C]CH), 7.21–7.45(m, 6H, CHar),
6.77–6.84 (m, 3H, CHar), 3.96 (s, 2H, CH2), 3.79 (s, 6H, OCH3); dC NMR
(100 MHz, CDCl3): 168.54, 159.74, 141.02, 135.27, 129.43, 129.15,
128.72, 128.53, 120.24, 113.71, 111.37, 55.05, 52.08, 33.10; ESI(HRMS)
(m/z) calcd for C18H19NaO3 (MþNa)þ 305.1154, found 305.1158.
4.3. Representative procedure for cross-coupling of chlorides
of Baylis–Hillman adduct with triarylbismuths
A hot-oven dried Schlenk tube was charged with methyl-
(2-chloromethyl)-3-phenylacrylate (0.825 mmol, 0.174 g) followed
by triphenylbismuth (0.25 mmol, 0.11 g), Cs2CO3 (0.75 mmol,
0.246 g), Pd2(dba)3 (0.0225 mmol, 0.0206 g) and DMA (3 mL) sol-
vent under nitrogen atmosphere. The reaction mixture was stirred
in an oil bath at 90 ꢀC for 1 h. After the reaction time, contents were
cooled, quenched with water (10 mL) and extracted with ethyl
acetate (3ꢁ15 mL). The combined organic extract was washed with
water (2ꢁ10 mL), brine (10 mL) and dried over anhydrous MgSO4.
The extract was concentrated under reduced pressure to obtain the
crude product mixture. This was purified on silica gel by column
chromatography (1% EtOAc/petroleum ether) to afford 2-benzyl-3-
phenylacrylic acid methyl ester (3.1) as colourless oil (0.143 g, 76%).
The product was identified by spectroscopic analysis and in com-
parison with the literature data.
4.4.6. 2-(4-Ethoxybenzyl)-3-phenylacrylic acid methyl ester
(3.6). The crude product was purified by column chromatography
using (1.5% ethyl acetate in petroleum ether) to give 3.6 as col-
ourless oil (162 mg, 73%); Rf (2.5% ethyl acetate in petroleum ether)
0.40; IR (neat, cmꢂ1): 3028, 2980,1712,1509,1437,1393,1243,1048,
806; dH NMR (400 MHz, CDCl3): 7.92 (s, 1H, C]CH), 7.33–7.41
(m, 5H, CHar), 7.12 (d, J¼8.32 Hz, 2H, CHar), 6.84 (d, J¼8.28 Hz, 2H,
CHar), 4.02 (q, J¼7.08, 14.08 Hz, 2H, OCH2CH3), 3.90 (s, 2H, CH2),
3.77 (s, 3H, OCH3), 1.42 (t, J¼6.56 Hz, 3H, OCH2CH3); dC NMR
(100 MHz, CDCl3): 168.68, 157.35, 140.52, 135.39, 131.15, 129.19,
128.82,128.66,128.52,114.55, 63.36, 52.05, 32.25,14.87; ESI(HRMS)
(m/z) calcd for C19H20NaO3 (MþNa)þ 319.1310, found 319.1311.
4.4. Spectral data
4.4.1. 2-Benzyl-3-phenylacrylic acid methyl ester (3.1)13a. The crude
product was purified by column chromatography using (1% ethyl
acetate in petroleum ether) to give 3.1 as colourless oil (137 mg,
73%); Rf (2.5% ethyl acetate in petroleum ether) 0.45; IR (neat,
cmꢂ1): 3026, 2949, 1712, 1629, 1435, 1264, 1202, 1089, 739; dH NMR
(500 MHz, CDCl3): 7.93 (s, 1H, C]CH), 7.18–7.36 (m, 10H, CHar), 3.95
(s, 2H, CH2), 3.74 (s, 3H, OCH3); dC NMR (125 MHz, CDCl3): 168.75,
141.09, 139.47, 135.41, 130.76, 129.74, 129.29, 128.67, 128.63, 128.00,
126.21, 52.22, 33.24.
4.4.7. 2-(4-Fluorobenzyl)-3-phenylacrylic acid methyl ester
(3.7)13a. The crude product was purified by column chromatog-
raphy using (2% ethyl acetate in petroleum ether) to give 3.7 as light
yellow oil (160 mg, 79%); Rf (2% ethyl acetate in petroleum ether)
0.40; IR (neat, cmꢂ1): 2951, 2845, 1713, 1631, 1508, 1437, 1261, 1092,
815; dH NMR (500 MHz, CDCl3): 7.84 (s, 1H, C]CH), 7.24–7.27 (m,
5H, CHar), 7.04–7.07 (m, 2H, CHar), 6.86–6.91 (m, 2H, CHar), 3.83 (s,
2H, CH2), 3.67 (s, 3H, CH3); dC NMR (125 MHz, CDCl3): 168.45,
161.38 (d, JCF¼241.25 Hz), 141.04, 134.90, 130.57, 129.30, 129.24,
129.08, 128.83, 128.60, 115.27 (d, JCF¼21.25 Hz), 52.12, 32.33.
4.4.2. 2-(4-Methylbenzyl)-3-phenylacrylic acid methyl ester
(3.2)13a. The crude product was purified by column chromatogra-
phy using (1% ethyl acetate in petroleum ether) to give 3.2 as col-
ourless oil (180 mg, 90%); Rf (2.5% ethyl acetate in petroleum ether)
0.44; IR (neat, cmꢂ1): 3024, 2949, 1714, 1630, 1513, 1436, 1262, 1203,
1088, 779; dH NMR (500 MHz, CDCl3): 7.91 (s, 1H, C]CH), 7.02–7.42
(m, 9H, CHar), 3.91 (s, 2H, CH2), 3.74 (s, 3H, OCH3), 2.31 (s, 3H, CH3); dC
NMR (125 MHz, CDCl3): 168.67,140.77,136.20,135.55,135.34,130.83,
129.22, 129.18, 128.69, 128.52, 127.74, 52.08, 32.70, 20.98; ESI(HRMS)
(m/z) calcd for C18H19O2, (MþH)þ 267.1385, found 267.1381.
4.4.8. 2-(4-Chlorobenzyl)-3-phenylacrylic acid methyl ester
(3.8)13a. The crude product was purified by column chromatography
using (1% ethyl acetate in petroleum ether) to give 3.8 as colourless oil,
(182 mg, 85%); Rf (2% ethyl acetate in petroleum ether) 0.38; IR (neat,
cmꢂ1): 2949, 1713, 1490, 1435, 1261, 1204, 1089, 833; dH NMR
(400 MHz, CDCl3): 7.95 (s,1H, C]CH), 7.30–7.42 (m, 5H, CHar), 7.26 (d,
J¼8.52 Hz, 2H,CHar), 7.13 (d, J¼8.28 Hz, 2H, CHar), 3.92(s,2H, CH2), 3.77
(s, 3H, OCH3); dC NMR (100 MHz, CDCl3): 168.35, 141.23, 137.93, 135.21,
131.93, 130.31, 129.61, 129.29, 129.07, 128.85, 128.63, 52.06, 32.58.
4.4.3. 2-(3-Methylbenzyl)-3-phenylacrylic acid methyl ester
(3.3). The crude product was purified by column chromatography
using (1% ethyl acetate in petroleum ether) to give 3.3 as colourless
oil (181 mg, 91%); Rf (2.5% ethyl acetate in petroleum ether) 0.44; IR
(neat, cmꢂ1): 2949, 2855, 1714, 1606, 1436, 1236, 1033, 772; dH NMR
4.4.9. 2-(3-Chlorobenzyl)-3-phenylacrylic acid methyl ester
(3.9). The crude product was purified by column chromatography
using (2% ethyl acetate in petroleum ether) to give 3.9 as colourless

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M.L.N. Rao et al. / Tetrahedron 66 (2010) 3623–3632
oil (150 mg, 70%); Rf (2% ethyl acetate in petroleum ether) 0.38; IR
(neat, cmꢂ1): 2951, 1714, 1508, 1436, 1261, 1222, 1018, 924, 759; dH
NMR (500 MHz, CDCl3): 7.85 (s, 1H, C]CH), 7.02–7.34 (m, 9H, CHar),
3.80 (s, 2H, CH2), 3.67 (s, 3H, OCH3); dC NMR (100 MHz, CDCl3):
168.28, 142.93, 141.50, 135.86, 135.13, 134.38, 129.71, 128.88, 128.64,
128.23, 126.38, 52.42, 32.87; ESI(HRMS) (m/z) calcd for
C17H15ClNaO2 (Mꢂ2HþNa)þ 307.0513, found 307.0719.
1346, 1204, 1156, 924, 820; dH NMR (500 MHz, CDCl3)
8.18(d, J¼8.55 Hz, 2H, CHar), 7.86 (s, 1H, C]CH), 7.47 (d, J¼8.60 Hz,
2H, CHar), 7.02(d, J¼8.05 Hz, 2H, CHar), 6.79 (d, J¼8.60 Hz, 2H, CHar),
3.97 (q, J¼7.45, 6.92 Hz, 2H, OCH2CH3), 3.82 (s, 2H, CH2), 3.75 (s, 3H,
OCH3), 1.37 (t, J¼7.45, 6.90 Hz, 3H, OCH2CH3); dC NMR (125 MHz,
CDCl3) 167.87, 157.53, 147.41, 141.85, 139.77, 137.75, 134.54, 129.81,
128.67, 123.72, 114.66, 63.35, 52.39, 32.24, 14.81; ESI(HRMS) (m/z)
calcd for C19H19NNaO5 (MþNa)þ 364.1161, found 364.1164.
4.4.10. 2-Benzyl-3-(4-nitrophenyl) acrylic acid methyl ester
(3.10)13a. The crude product was purified by column chromatog-
raphy using (2% ethyl acetate in petroleum ether) to give 3.10 as
light yellow solid (166 mg, 75%); mp 96–98 ꢀC; Rf (10% ethyl acetate
in petroleum ether) 0.50; IR (neat, cmꢂ1): 3029, 2925, 2852, 1714,
1596, 1515, 1344, 1204, 1087, 927; dH NMR (500 MHz, CDCl3) 8.12
(d, J¼8.60 Hz, 2H, CHar), 7.85 (s, 1H, C]CH), 7.42 (d, J¼8.60 Hz, 2H,
CHar), 7.13–7.27 (m, 3H, CHar), 7.07 (d, J¼7.20 Hz, 2H, CHar), 3.84
(s, 2H, CH2), 3.71 (s, 3H, OCH3); dC NMR (125 MHz, CDCl3) 167.81,
147.45, 141.77, 138.39, 138.18, 134.10, 129.79, 128.73, 127.71, 126.47,
123.77, 52.44, 33.11.
4.4.15. 2-(4-Fluorobenzyl)-3-(4-nitrophenyl) acrylic acid methyl ester
(3.15). The crude product was purified by column chromatography
using (2% ethyl acetate inpetroleum ether) to give 3.15 as light yellow
solid (153 mg, 65%); mp 97–99 ꢀC; Rf (10% ethyl acetate in petroleum
ether) 0.48; IR (neat, cmꢂ1): 2925, 2852, 1726, 1434, 1257, 1098, 757;
dH NMR (400 MHz, CDCl3) 8.13(d, J¼8.76 Hz, 2H, CHar), 7.83 (s, 1H,
C]CH), 7.40 (d, J¼8.52 Hz, 2H, CHar), 6.88–7.04 (m, 4H, CHar), 3.79 (s,
2H, CH2), 3.71 (s, 3H, OCH3); dC NMR (100 MHz, CDCl3) 167.62, 161.54
(d, JCF¼243.00 Hz), 147.56, 141.67, 138.20, 134.10, 129.72, 129.24,
129.16,123.81,115.53(d, JCF¼22.00 Hz), 52.42,32.36;ESI(HRMS)(m/z)
calcd for C17H14FNNaO4 (MþNa)þ 338.0805, found 338.0808.
4.4.11. 2-(4-Methylbenzyl)-3-(4-nitrophenyl) acrylic acid methyl ester
(3.11). The crude product was purified by column chromatography
using (2% ethyl acetate in petroleum ether) to give 3.11 as light
yellow solid (162 mg, 70%); mp 130–132 ꢀC; Rf (10% ethyl acetate in
petroleum ether) 0.48; IR (neat, cmꢂ1): 3111, 2956, 2925, 1713, 1514,
1436, 1344, 1258, 1203, 977; dH NMR (400 MHz, CDCl3)
8.17(d, J¼8.80 Hz, 2H, CHar), 7.88 (s, 1H, C]CH), 7.47 (d, J¼8.56 Hz,
2H, CHar), 7.09 (d, J¼8.04 Hz, 2H, CHar), 7.02 (d, J¼8.04 Hz, 2H, CHar),
3.85 (s, 2H, CH2), 3.76 (s, 3H, OCH3), 2.30 (s, 3H, CH3); dC NMR
(100 MHz, CDCl3) 167.85, 147.46, 141.84, 137.94, 136.01, 135.27,
134.37, 129.81, 129.42, 127.58, 123.73, 52.39, 32.73, 20.96;
ESI(HRMS) (m/z) calcd for C18H17NNaO4 (MþNa)þ 334.1055, found
334.0756.
4.4.16. 2-(4-Chlorobenzyl)-3-(4-nitrophenyl) acrylic acid methyl es-
ter (3.16). The crude product was purified by column chromatog-
raphy using (2% ethyl acetate in petroleum ether) to give 3.16 as
pale yellow solid (149 mg, 60%); mp 103–105 ꢀC; Rf (10% ethyl ac-
etate in petroleum ether) 0.48; IR (neat, cmꢂ1): 3108, 2953, 2850,
1713, 1633, 1599, 1343, 1257, 1207, 927, 821; dH NMR (500 MHz,
CDCl3): 8.19(d, J¼9.15 Hz, 2H, CHar), 7.91 (s, 1H, C]CH), 7.45 (d,
J¼8.60 Hz, 2H, CHar), 7.23–7.26(m, 2H, CHar), 7.06 (d, J¼8.60 Hz, 2H,
CHar), 3.85 (s, 2H, CH2), 3.76 (s, 3H, OCH3); dC NMR (125 MHz,
CDCl3): 167.53, 147.54, 141.57, 138.49, 136.91, 133.64, 132.30, 129.70,
129.09, 128.84, 123.84, 52.48, 32.54; ESI(HRMS) (m/z) calcd for
C17H14ClNNaO4 (MþNa)þ 354.0509, found 354.0507.
4.4.12. 2-(3-Methylbenzyl)-3-(4-nitrophenyl) acrylic acid methyl ester
(3.12). The crude product was purified by column chromatography
using (2% ethyl acetate in petroleum ether) to give 3.12 as light
yellow solid (180 mg, 80%); mp 112–114 ꢀC; Rf (10% ethyl acetate in
petroleum ether) 0.48; IR (neat, cmꢂ1): 3006, 2923, 1713,1598,1517,
1347, 1204, 980, 928; dH NMR (500 MHz, CDCl3): 8.17 (d, J¼8.60 Hz,
2H, CHar), 7.90 (s, 1H, C]CH), 7.47 (d, J¼8.60 Hz, 2H, CHar), 7.17
(t, J¼7.45 Hz, 1H, CHar), 6.92–7.01 (m, 3H, CHar), 3.86 (s, 2H, CH2),
3.77 (s, 3H, OCH3), 2.30 (s, 3H, CH3); dC NMR (125 MHz, CDCl3):
167.86, 147.45, 141.80, 138.12, 134.15, 129.82, 128.61, 128.47, 127.26,
124.64, 123.75, 52.43, 33.03, 21.44; ESI(HRMS) (m/z) calcd for
C18H17NO4 (MþH)þ 312.1236, found 312.1239.
4.4.17. 2-(3-Chlorobenzyl)-3-(4-nitrophenyl) acrylic acid methyl es-
ter (3.17). The crude product was purified by column chromatog-
raphy using (2% ethyl acetate in petroleum ether) to give 3.17 as
pale yellow solid (149 mg, 60%); mp 99–101 ꢀC; Rf (10% ethyl ace-
tate in petroleum ether) 0.47; IR (neat, cmꢂ1): 3108, 2928, 2851,
1717, 1633, 1596, 1345, 1204, 1092, 977, 854; dH NMR (500 MHz,
CDCl3): 8.21(d, J¼9.15 Hz, 2H, CHar), 7.94 (s, 1H, C]CH), 7.46 (d,
J¼8.05 Hz, 2H, CHar), 7.01–7.25 (m, 4H, CHar), 3.87 (s, 2H, CH2), 3.78
(s, 3H, OCH3); dC NMR (125 MHz, CDCl3): 167.48, 147.58, 141.52,
138.77, 134.57, 133.29, 129.95, 127.88, 126.77, 125.93, 123.87, 52.53,
32.81; ESI (HRMS) (m/z) calcd for C17H14ClNNaO4 (MþNa)þ
354.0509, found 354.0508.
4.4.13. 2-(4-Methoxybenzyl)-3-(4-nitrophenyl) acrylic acid methyl
ester (3.13). The crude product was purified by column chroma-
tography using (4% ethyl acetate in petroleum ether) to give 3.13 as
pale yellow solid (153 mg, 63%); mp 107–109 ꢀC; Rf (10% ethyl
acetate in petroleum ether) 0.43; IR (neat, cmꢂ1): 3017, 2955, 1715,
1599, 1515, 1347, 1203, 1180, 1156, 928, 855; dH NMR (500 MHz,
CDCl3) 8.17 (d, J¼8.60 Hz, 2H, CHar), 7.86 (s, 1H, C]CH), 7.47
(d, J¼8.60 Hz, 2H, CHar), 7.03(d, J¼9.20 Hz, 2H, CHar), 6.81
(d, J¼8.60 Hz, 2H, CHar), 3.89 (s, 2H, CH2), 3.76 (s, 6H, OCH3); dC
NMR (125 MHz, CDCl3) 167.86, 158.17, 147.44, 141.84, 139.78, 137.80,
134.51, 129.81, 128.70, 123.75, 114.12, 55.20, 52.41, 32.24;
ESI(HRMS) (m/z) calcd for C18H17NNaO5 (MþNa)þ 350.1004, found
350.1006.
4.4.18. 2-(3-Methylbenzyl)-3-(4-chlorophenyl) acrylic acid methyl
ester (3.18). The crude product was purified by column chroma-
tography using (2% ethyl acetate in petroleum ether) to give 3.18 as
light yellow oil (180 mg, 80%); Rf (2.5% ethyl acetate in petroleum
ether) 0.44; IR (neat, cmꢂ1): 2950, 2923, 1714, 1490, 1436, 1279,
1202, 836, 771; dH NMR (400 MHz, CDCl3) 7.89(s, 1H, C]CH),
7.18–7.36 (m, 5H, CHar), 6.98–7.10 (m, 3H, CHar), 3.91 (s, 2H, CH2),
3.78 (s, 3H, OCH3), 2.34 (s, 3H, CH3); dC NMR (100 MHz, CDCl3):
168.42, 139.54, 138.85, 138.19, 133.72, 131.23, 130.49, 128.79, 128.54,
127.01, 124.73, 52.18, 32.98, 21.45; ESI(HRMS) (m/z) calcd for
C18H17ClNaO2 (MþNa)þ 323.0815, found 323.0819.
4.4.19. 2-(3-Methoxybenzyl)-3-(4-chlorophenyl) acrylic acid methyl
ester (3.19). The crude product was purified by column chroma-
tography using (2% ethyl acetate in petroleum ether) to give 3.19 as
light yellow oil (191 mg, 81%); Rf (2.5% ethyl acetate in petroleum
ether) 0.39; IR (neat, cmꢂ1): 2949, 2837, 1713, 1598, 1489, 1308,
1263, 1203, 1089, 1013, 774; dH NMR (500 MHz, CDCl3) 7.86(s, 1H,
C]CH), 7.15–7.31 (m, 5H, CHar), 6.64–6.83 (m, 3H, CHar), 3.89 (s, 2H,
4.4.14. 2-(4-Ethoxybenzyl)-3-(4-nitrophenyl) acrylic acid methyl ester
(3.14). The crude product was purified by column chromatography
using (4% ethyl acetate in petroleum ether) to give 3.14 as pale
yellow solid (152 mg, 60%); mp 124–126 ꢀC; Rf (10% ethyl acetate in
petroleum ether) 0.45; IR (neat, cmꢂ1): 2927, 2852, 1717, 1598, 1515,

M.L.N. Rao et al. / Tetrahedron 66 (2010) 3623–3632
3631
CH2), 3.76 (s, 3H, OCH3), 3.75 (s, 3H, OCH3); dC NMR (125 MHz,
CDCl3) 168.48, 159.92, 139.87, 134.88, 133.77, 130.61, 129.70, 128.93,
120.24, 113.84, 111.50, 55.21, 52.35, 33.17; ESI(HRMS) (m/z) calcd for
C18H17ClNaO3 (MþNa)þ 339.0764, found 339.0765.
(138 mg, 74%); Rf (0.5% ethyl acetate in petroleum ether) 0.45; IR
(neat, cmꢂ1): 2955, 2928, 1714, 1436, 1268, 1201, 766, 699; dH NMR
(400 MHz, CDCl3) 6.90–7.16 (m, 5H, CHar), 3.68 (s, 3H, OCH3), 3.66
(s, 2H, CH2), 2.22–2.31(m, 5H, CH3, –CH2–), 1.29–1.47 (m, 4H, –CH2–
CH2), 0.82–0.94 (m, 3H, –CH3); dC NMR (100 MHz, CDCl3) 168.18,
144.39, 139.62, 137.79, 130.69, 128.91, 128.16, 126.67, 125.13, 51.67,
32.18, 30.78, 28.63, 22.43, 21.40, 13.83; ESI(HRMS) (m/z) calcd for
C16H22NaO2 (MþNa)þ 269.1517, found 269.1512.
4.4.20. 2-(3-Methylbenzyl)-3-(furan-2-yl) acrylic acid methyl ester
(3.20). The crude product was purified by column chromatography
using (2% ethyl acetate in petroleum ether) to give 3.20 as brown oil
(151 mg, 78%); Rf (2.5% ethyl acetate in petroleum ether) 0.43; IR
(neat, cmꢂ1): 2952, 1710, 1632, 1437, 1205, 1093, 1020, 778; dH NMR
(500 MHz, CDCl3): 7.39 (s, 1H, C]CH), 6.90–7.17 (m, 5H, CHar), 6.44
(d, J¼3.45 Hz, 1H, CHar), 6.30 (d, J¼3.60 Hz, 1H, CHar), 3.95 (s, 2H,
CH2), 3.68 (s, 3H, OCH3), 2.22 (s, 3H, CH3); dC NMR (125 MHz,
CDCl3):168.44, 153.07, 138.95, 137.86, 129.10, 128.22, 126.82, 125.66,
125.23, 117.57, 113.97, 52.22, 33.25, 21.42; ESI(HRMS) (m/z) calcd for
C16H16NaO3 (MþNa)þ 279.0997, found 279.0990.
4.4.26. 3-Butyl-2-(3-methoxybenzyl) acrylic acid methyl ester
(3.26). The crude product was purified by column chromatogra-
phy using (0.5% ethyl acetate in petroleum ether) to give 3.26 as
colourless oil (147 mg, 75%); Rf (0.5% ethyl acetate in petroleum
ether) 0.43; IR (neat, cmꢂ1): 2928, 2857, 1713, 1600, 1435, 1261,
1144, 1048, 769; dH NMR (400 MHz, CDCl3): 7.15 (t, J¼7.56 Hz, 1H,
CHar), 6.93 (t, J¼7.56 Hz, 1H, CHar), 6.69–6.76 (m, 3H, CHar), 3.75
(s, 3H, OCH3), 3.67 (s, 3H, OCH3), 3.65 (s, 2H, CH2), 2.25 (q, J¼7.32,
7.56 Hz, 2H, –CH2–), 1.24–1.46 (m, 4H, –CH2–CH2–), 0.88–0.90
(m, 3H, –CH3); dC NMR (100 MHz, CDCl3): 168.11, 159.59, 144.55,
141.35, 130.48, 129.19, 120.57, 113.98, 111.17, 55.05, 51.70, 32.28,
30.79, 28.64, 22.44, 13.83; ESI(HRMS) (m/z) calcd for C16H22O3
(MþH)þ 263.1647, found 263.1646.
4.4.21. 2-(3-Methoxybenzyl)-3-(furan-2-yl) acrylic acid methyl ester
(3.21). The crude product was purified by column chromatography
using (2.5% ethyl acetate in petroleum ether) to give 3.21 as brown
oil (167 mg, 82%); Rf (2.5% ethyl acetate in petroleum ether) 0.39; IR
(neat, cmꢂ1): 2951, 1709, 1627, 1437, 1256, 1205, 1047, 775; dH NMR
(500 MHz, CDCl3): 7.39(s, 1H, C]CH), 7.10 (t, J¼7.90 Hz, 1H, CHar),
6.72–6.79 (m, 3H, CHar), 6.65 (dd, J¼2.05, 8.25 Hz, 1H, CHar), 6.45
(d, J¼3.40 Hz, 1H, CHar), 6.31 (d, J¼3.45 Hz, 1H, CHar), 3.98 (s, 2H,
CH2), 3.69 (s, 6H, OCH3); dC NMR (125 MHz, CDCl3): 168.34, 159.56,
153.03, 140.67, 129.27, 127.75, 125.71, 120.72, 117.72, 114.05, 111.36,
55.09, 52.20, 33.32; ESI(HRMS) (m/z) calcd for C16H16NaO4
(MþNa)þ 295.0944, found 295.0944.
4.4.27. 2-(3-Methoxybenzyl)-3-(4-nitrophenyl) acrylic acid methyl
ester (3.27). The crude product was purified by column chroma-
tography using (4% ethyl acetate in petroleum ether) to give 3.27 as
pale yellow solid (182 mg, 75%); mp 108–110 ꢀC; Rf (10% ethyl
acetate in petroleum ether) 0.45; IR (neat, cmꢂ1): 3016, 2930, 2836,
1713, 1603, 1518, 1347, 1315, 1293, 1049, 896; dH NMR (400 MHz,
CDCl3): 8.21(d, J¼8.52 Hz, 2H, CHar), 7.94 (s, 1H, C]CH), 7.51
(d, J¼9.04 Hz, 2H, CHar), 7.22–7.28 (m, 1H, CHar), 6.66–6.81 (m, 3H,
CHar), 3.91 (s, 2H, CH2), 3.81 (s, 3H, CH3), 3.79 (s, 3H, CH3); dC NMR
(100 MHz, CDCl3): 167.74, 159.85, 147.46, 141.72, 140.00, 138.25,
133.91, 129.80, 123.73, 119.99, 113.79, 111.43, 55.08, 52.41, 33.07;
ESI(HRMS) (m/z) calcd for C18H17NNaO5 (MþNa)þ 350.1004, found
350.1004.
4.4.22. 2-(4-Methylbenzyl)-3-phenylacrylonitrile (3.22)13b. The crude
product was purified by column chromatography using (1% ethyl
acetate in petroleum ether) to give 3.22 as colourless oil (131 mg,
75%); Rf (2.5% ethyl acetate in petroleum ether) 0.58; IR (neat,
cmꢂ1): 2919, 2851, 2211, 1624, 1513, 1448, 1215, 738; dH NMR
(500 MHz, CDCl3): 7.71(d, J¼6.90 Hz, 2H, CHar), 7.38–7.41 (m, 3H,
CHar), 7.13–7.20 (m, 4H, CHar), 6.94 (s, 1H, C]CH), 3.66 (s, 2H, CH2),
2.34 (s, 3H, CH3); dC NMR (125 MHz, CDCl3): 143.77, 136.96, 133.56,
133.30, 130.02, 129.54, 128.75, 128.63, 118.72, 111.02, 41.76, 21.05.
Acknowledgements
We thank the Department of Science and Technology (DST),
New Delhi for supporting this work under green chemistry pro-
gram (SR/S5/GC-11/2008). D.B. and R.J.D. thank IIT Kanpur and CSIR,
New Delhi for research fellowships respectively.
4.4.23. 2-(3-Methylbenzyl)-3-phenylacrylonitrile (3.23). The crude
product was purified by column chromatography using (2.5% ethyl
acetate in petroleum ether) to give 3.23 as colourless oil (110 mg,
63%); Rf (2.5% ethyl acetate in petroleum ether) 0.58; IR (neat,
cmꢂ1): 3029, 2919, 2210, 1585, 1448, 1213, 1036, 771; dH NMR
(500 MHz, CDCl3): 7.41–7.72(m, 2H, CHar), 7.14–7.40 (m, 7H, CHar),
6.94 (s, 1H, C]CH), 3.66 (s, 2H, CH2), 2.34 (s, 3H, CH3); dC NMR
(125 MHz, CDCl3): 144.08, 139.82, 138.22, 134.68, 130.40, 129.75,
128.60,128.22, 126.05, 118.85, 110.95, 42.25, 21.63; ESI(HRMS) (m/z)
calcd for C17H14N (MꢂH)þ 232.1132 found, 232.1135.
Supplementary data
Supplementary data containing 1H and 13C NMR spectra of all
the products can be found in the online version. Supplementary
data associated with this article can be found in online version at
doi:10.1016/j.tet.2010.03.020.
4.4.24. 3-Butyl-2-(4-methylbenzyl) acrylic acid methyl ester (3.24).
The crude product was purified by column chromatography using
(0.5% ethyl acetate in petroleum ether) to give 3.24 as colourless oil
(133 mg, 72%); Rf (0.5% ethyl acetate in petroleum ether) 0.45; IR
(neat, cmꢂ1): 2955, 2928, 1714, 1513, 1436, 1270, 1139, 777; dH NMR
(400 MHz, CDCl3): 6.89–7.08 (m, 5H, CHar), 3.67 (s, 3H, OCH3), 3.63
(s, 2H, CH2), 2.23–2.31 (m, 5H, CH3, –CH2–), 1.24–1.51 (m, 4H, –CH2–
CH2), 0.84–0.94 (m, 3H, –CH3); dC NMR (100 MHz, CDCl3) 168.18,
144.18, 136.65, 135.34, 130.86, 128.97, 128.01, 51.65, 31.87, 30.82,
28.61, 22.44, 20.94, 13.84; ESI(HRMS) (m/z) calcd for C16H22NaO2
(MþNa)þ 269.1517, found 269.1510.
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