Metal-free allylation of electron-rich heteroaryl boronic acids with allylic alcohols

Article abstract of DOI:10.1016/j.tet.2016.02.047

A convenient and regioselective cross-coupling of heteroaryl boronic acids with allylic alcohols under catalyst-free reaction conditions is described. The developed procedure is simple, works under external oxidant- and metal-free conditions, and proves to be very general with an unprecedented ortho-selectivity. This approach represents one of the very few examples of ortho-functionalization of boronic acids.

Full text of DOI:10.1016/j.tet.2016.02.047

Tetrahedron 72 (2016) 1873e1880
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Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Metal-free allylation of electron-rich heteroaryl boronic acids with
allylic alcohols
,
,
,
,
Xue-Dong Li a b, Li-Jun Xie a b, De-Long Kong a b, Li Liu a, Liang Cheng a
*
a Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry,
Chinese Academy of Sciences, Beijing 100190, PR China
b University of Chinese Academy of Sciences, Beijing 100049, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 13 January 2016
Received in revised form 20 February 2016
Accepted 22 February 2016
Available online 23 February 2016
A convenient and regioselective cross-coupling of heteroaryl boronic acids with allylic alcohols under
catalyst-free reaction conditions is described. The developed procedure is simple, works under external
oxidant- and metal-free conditions, and proves to be very general with an unprecedented ortho-selec-
tivity. This approach represents one of the very few examples of ortho-functionalization of boronic acids.
Ó 2016 Elsevier Ltd. All rights reserved.
Keywords:
Allylation
Heteroaryl boronic acids
Metal-free reactions
Allylic alcohols
ortho-Selectivity
1. Introduction
required, thus the overall process would become highly efficient
and atom-economical. Despite their simple and efficient operation,
Carbonecarbon bond formation is the essence of organic syn-
thesis and provides the foundation for generating more compli-
cated organic compounds from the simpler ones.1 The
transformations of allylic compounds are of paramount importance
in CeC bond formations. The double bond can participate in
a number of synthetically useful transformations, which provide
resourceful access to highly diverse molecules. A well-established
pathway for the generation of allylic products in current organic
synthesis heavily relies on the transition-metal (Pd, Rh, Ag, Ir, etc.)
catalyzed cross-coupling reactions.2 In addition, previously de-
veloped reactions typically involve the use of allylic halides or al-
lylic carboxylates, which usually produce stoichiometric quantities
of hazardous byproducts (Scheme 1a,b). With this in mind, it has
been recognized that it is highly desirable to develop new strategies
for the generation of allylic intermediates that utilize inexpensive
substrates, proceed under mild conditions, and are environmen-
tally benign.
alcohols are rarely used as substrates in allylation because of the
low tendency for hydroxide to act as a leaving group.3 In our pre-
vious work, we have recently reported Lewis/Brønsted acids cata-
lyzed alkylation of indole and its derivatives with allylic alcohols.4
Nevertheless, it remains a great challenge to synthesize the allylic
products with a rational design at the molecular level using cheap
and simple processes.
One such strategy is the utilization of allylic alcohol. If allylic
alcohols can be used directly as alkylation agents, preparation of
the corresponding halides or carboxylates would no longer be
Scheme 1. Cross-coupling of allylic alcohols/esters with boronic acids.
* Corresponding author. Tel.: þ86 10 61943102; fax: þ86 10 62554449; e-mail
address: chengl@iccas.ac.cn (L. Cheng).
http://dx.doi.org/10.1016/j.tet.2016.02.047
0040-4020/Ó 2016 Elsevier Ltd. All rights reserved.

1874
X.-D. Li et al. / Tetrahedron 72 (2016) 1873e1880
In very recent times, catalyst-free processes that do not require
thienyl product 3a was identified as the major isomer. In contrast,
the use of DMSO afforded a slight preference for the ipso-
substituted product 4a (3a:4a 1:2, Table 1, entry 8). After a screen-
ing of reaction conditions, the optimum condition for the CeC bond
formation reaction were identified as mesitylene at 120 ꢀC, leading
to the most significant increase of product formation with 69% yield
and 9:1 selectivity (3a:4a, Table 1, entry 12). In an attempt to im-
prove the yield and selectivity further, molecular sieve additives
were tested. Unfortunately, all those efforts led to a dramatic de-
crease of product formation and distribution (Table 1, entries
15e16).
a metal or small molecules catalyst are of great importance because
such procedures obviate the need for disposing the catalysts from
the reaction residues and eliminating traces of metals (if any) from
final compounds.5 On the basis of previous work, we initiated
a research program with the aim of exploring catalyst-free trans-
formations of allylic alcohols with boronic acids in cross-coupling
reactions. Use of boronic acids as the coupling partner was our
first choice, owing to the advantages of these reagents regarding
stability, commercial availability and relatively low toxicity when
compared with other organometallics.6 Herein, we describe our
preliminary investigations toward an unprecedented regioselective
and catalyst-free cross-coupling reactions of allylic alcohols with
a series of electron-rich heteroaryl boronic acids and related reac-
tants5b,7 (Scheme 1c).
Afterward, the scope of the novel catalyst-free cross-coupling
was explored between
a set of allylic alcohols 1 and 2-
thienylboronic acid 2a. As shown in Scheme 2, both electron-
donating and electron-withdrawing substituents were well toler-
ated, and moderate to good yields and regioselectivities of the
corresponding ortho-substituted products were obtained. A broad
range of functional groups, such as chloro (3b, 3f and 3j), bromo
(3c, 3g and 3k), methyl (3d, 3h and 3l), methoxy (3e and 3i) and
fluoro (3m), were compatible with this protocol. Notably, para- and
meta-substituents led to the desired products with high yields and
good ortho-selectivities (Scheme 2, products 3bei). However,
substituents in the ortho-position on the allylic alcohols (except the
one with methyl group) generally provided products in poor yields
2. Results and discussion
The reaction of allylic alcohol 1a with 2-thienylboronic acid 2a
was selected as a prototype reaction.8,9 To our delight the reaction
proceeded smoothly with 12 h in 39% yield (Table 1, entry 1). Sur-
prisingly the allylic products were formed in a regioselective
manner, predominantly with an unprecedented ortho-allylation
product 2-thienyl substituted 3a as the major component, not the
ordinary ipso-product 4a (3a:4a 3:1), although the first attempt of
cross-coupling suffered from an incomplete conversion and partial
dimerization of alcohol.
Table 1
Screening of reaction Conditionsa
Entry
Solvent
Time (h)
Yield (%)b
Ratio (3a:4a)c
1
2
3
CH2Cl2
Et2O
THF
Dioxane
MeOH
H2O
CH3CN
DMSO
DMF
12
18
29
24
24
24
6
24
24
4
3
8
1
3
8
8
39
16
20
Trace
Trace
Trace
32
30
15
75
59
69
62
55
49
66
3:1
3:1
2:1
NA
NA
NA
5:1
1:2
3:1
6:1
4:1
9:1
4:1
6:1
2:1
8:1
4
5d
6
7
8e
9e
10e
11f
12f
13f
14f
15g
16h
Toluene
Xylene
Mesitylene
Dichlorobenzene
Anisole
Mesitylene
Mesitylene
The most successful entry is highlighted in bold.
a
Reaction conditions: allylic alcohol 1a (0.15 mmol, 1.0 equiv), 2-thienylbornic
acid 2a (0.22 mmol, 1.5 equiv), solvent (0.15 M), reflux.
b
Combined yields are given for isolated products after column chromatography.
c
Regioisomeric ratios determined by 1H NMR of the final products.
d
Methyl ester of 1a was isolated as the major product.
e
Reaction temperature: 110 ꢀC.
f
Reaction temperature: 120 ꢀC.
g
ꢀ
3 A molecular sieve (MS, 20 mg) was used as the additive.
h
ꢀ
4 A MS (20 mg) was used as the additive.
We observed that the formation of unusual product 3a occurred
in the presence of a variety of solvents (Table 1, entries 2e14). The
use of dioxane, methanol or water significantly decreased the re-
activity, leading to trace products (Table 1, entries 4e6). When
methanol was used as the solvent, only methyl ester of 1a was
isolated as the major product (Table 1, entry 5). In most cases, the 3-
Scheme 2. Substrate scope. Reaction conditions: allylic alcohol
1 (1.5 equiv),
2-thienylboronic acid 2a (1.0 equiv), mesitylene (0.15e0.30 M), under a nitrogen
atmosphere, 120 ꢀC. Combined yields are given for isolated products after column
chromatography. The regioisomeric ratios in the parentheses (ortho:ipso) are
determined by 1H NMR.

X.-D. Li et al. / Tetrahedron 72 (2016) 1873e1880
1875
and low selectivity (Scheme 2, products 3jek, 3m), probably due to
steric interactions. To the best of our knowledge, this is the first
example of ortho-functionalization of heteroaryl boronic acids with
allylic alcohol.10,11 Remarkably, the presence of a metal catalyst was
not necessarydthe reaction proceeded simply by heating both
reagents in the solvent. It is noteworthy that the heterocyclic sub-
strate, such as 1,3-di-2-thienyl-2-propen-1-ol 1n, was also toler-
ated under the reaction conditions, providing an expeditious access
to biologically important tri-heteroaryl compounds such as 3n.12
Unfortunately, the reaction does not work with mono-substituted
heteroarene boronic acids (Scheme 4). We first examined the re-
actions between simple thiophene 5 and allylic alcohol 1a with or
without boronic acid (Scheme 4a). The exclusive formation of
2-thienyl ipso-product 4a with boronic acid was used clearly
showed the need of pre-activated heteroaryl starting materials.
One the other hand, as thiophene could be generated from the
proto-deboronation of thienyl boronic acid,13 thus some of 4a in
Table 1 and Scheme 2 could also be generated from this pathway. As
mentioned before, we did observe some dimerization product of
the alcohol during the screening process14 (Table 1). It is speculated
that the dimer might be involved in the conversion.9b,14a,b Indeed,
the reactive dimer 6, which was isolated as a diastereoisomeric
mixture, could be converted to 3a in 72% yield on treatment with 2-
thienyl boronic acid 2a in mesitylene for 24 h at 120 ꢀC, although
a little lower ortho-/ipso-ratio was obtained (Scheme 4b). In addi-
tion, when methyl ether 7 was used, a comparable amount of 3a
(54%) with a 9:1 regioselectivity (3a:4a) was obtained (Scheme 4c).
allylic alcohols, such as cinnamyl and a-vinylbenzyl alcohols, and
aliphatic allylic alcohols, possibly because of their relatively low
reactivity.
In the next experiments, we examined the substrate scope of
several heterocyclic boronic acids (Scheme 3). 3-Thienylboronic
acid 2b, 3-furanylboronic acid 2c, and 1-(tert-butoxycarbonyl)-
1H-pyrazol-5-ylboronic acid 2d exclusively gave the ortho-allyla-
tion products 4a, 4b and 4c, respectively. On the contrary, N-Boc-2-
pyrroleboronic acid 2e, benzo[b]thien-2-ylboronic acid 2f, 2-
benzofuranylboronic acid 2h and 3-benzofuranylboronic acid 2i
completely led to the ipso-allylation products 4dee, 4geh without
any detection of their ortho-isomers, while benzo[b]thien-3-
ylboronic acid 2g afforded the ipso-product 4f along with its or-
tho-isomer 4e in a yield of 63% (4f:4e 3:1), thus demonstrating
a subtle sensitivity to the substrate structures. Notably, Boc pro-
tecting group was also cleaved under the reaction condition (4d).
Other aryl/heteroaryl boronic acids, such as phenylboronic acid, 4-
hydroxybenzeneboronic acid, 2-naphthylboronic acid, 2-
furanylboronic
acid,
4-pyridinylboronic
acid
and
3-
pyridinylboronic acid, did not afford the desired products.
Scheme 4. Control experiments.
Regioselectivity is a challenge for the Lewis/Brønsted acid cat-
alyzed allylation of unsymmetrical allylic alcohols.15 Hence, the
reaction of two unsymmetrical allylic alcohols 8 and 9 under the
same conditions was then investigated. As shown in Scheme 4d,
both reactions proceeded smoothly to give the corresponding
products in 41 and 39% yields, respectively, with an identical
regioselectivity (10:11 2:1). It was found that the allylation site was
mainly determined by the electronic effect, and the reaction
generally occurred at the carbon adjacent to the electron-rich aryl
group owing to a carbocation intermediate involved in this
process.16 Finally, to test if other phenyl stabilized cation was ap-
plicable, diphenylmethanol 12 and triphenylmethanol 13, as typi-
cally used in FriedeleCrafts alkylations,15 were subjected to the
reaction. However, no product was detected under similar reaction
conditions (Scheme 4e).
Scheme 3. Substrate scope. Reaction conditions: allylic alcohol 1a (1.5 equiv), het-
erocyclic boronic acid 2 (1.0 equiv), mesitylene, 120 ꢀC. Combined yields are given for
a
isolated products after column chromatography. Water was used as the solvent.
b
Ratio refers to 4f:4e and was determined by 1H NMR.
With these results in hand, several control experiments were
carried out to gain information to elucidate the reaction mecha-
nism for this unusual ortho-functionalization of electron-rich
Taking the previous experiments7,11,14 into account and recon-
ciling them with our study, a reaction mechanism for the genera-
tion of cross-coupling products was proposed and outlined in

1876
X.-D. Li et al. / Tetrahedron 72 (2016) 1873e1880
Scheme 5. The present procedure proceeds in a manner similar to
that for Lewis/Brønsted acid catalyzed allylation with allylic alco-
hols, which might involve the formation of an allylic carbocation A
(path a) and/or the reactive dimer B (path b), the latter reacting
further in the presence of (heteroaryl)boronic acid to give the car-
bocation (path c) or directly to the allylation product. The electronic
effect may play a crucial role for the allylation-regioselectivity
owing to a carbocation intermediate involved in this trans-
formation. The higher ortho-/ipso-selectivity of thienyl boronic
acids in the allylation could be explained based on the partial
ionization of these heteroaryl boronic acids, which would further
increase electron density at the ortho-position of the heteroarene
ring, where an electrophilic aromatic substitution (EAS) reaction
with the allylic carbocation A or the dimer B occurred, followed by
the removal of the boronic acid moiety through proto-deborona-
tion.11 However, the strong ipso-selectivity from B(OH)2, as seen in
benzo-furanyl/thienyl analogous (Scheme 3), is still unclear, and
obviously more experiments are needed to clarify the unusual or-
tho-/ipso-directing group effect.
w) aqueous NaOH (0.15 equiv) gradually. The mixture was allowed
to be stirred at room temperature overnight. Large amounts of
yellow insoluble product precipitated during the procedure. The
precipitation was filtered and washed with water (3ꢁ50 mL) and
cold MeOH (3ꢁ10 mL) successively to give product
a,b-unsaturated
ketone chalcone as a solid. The product was pure enough to be used
in the next step without further purification. To a stirred solution of
a,b-unsaturated ketone chalcone (1.0 equiv) in MeOH was added
CeCl3$7H2O (1.0 equiv). The solution was cooled to 0 ꢀC and NaBH4
(1.1 equiv) was added. The mixture was stirred at room tempera-
ture for 1 h before water was added and exacted with CH2Cl2. The
combined organic phases were dried with Na2SO4, and the solvents
evaporated under vacuum. The pure compound was obtained after
flash chromatography on silica gel. Physical and spectroscopic data
are given below. For known compounds, only 1H/13C NMR data are
listed.
4.2.1. 1,3-Bis(4-chlorophenyl)prop-2-en-1-ol (1b).16a Pale yellow
solid. 1H NMR (300 MHz, CDCl3)
d 2.38 (s, 1H), 5.30e5.32 (d, 1H,
J¼6.3 Hz), 6.23e6.31 (dd, 1H, J¼6.6 Hz, 15.9 Hz), 6.56e6.61 (dd, 1H,
J¼0.9 Hz, 15.9 Hz), 7.26e7.32 (m, 8H).
4.2.2. 1,3-Bis(4-bromophenyl)prop-2-en-1-ol (1c).16a Pale yellow
solid. 1H NMR (300 MHz, CDCl3)
5.29e5.32 (dd, 1H, J¼1.8 Hz, 6.0 Hz), 6.25e6.32 (dd, 1H, J¼6.3 Hz,
15.9 Hz), 6.56e6.61 (d, 1H, J¼15.9 Hz), 7.20e7.29 (m, 4H), 7.40e7.49
(m, 2H).
d
2.25e2.26 (d, 1H, J¼3.0 Hz),
4.2.3. 1,3-Bi-p-tolylprop-2-en-1-ol (1d).16a Light yellow oil. 1H NMR
(300 MHz, CDCl3)
d
2.29e2.31 (sþs, 6H), 2.44 (s, 1H), 5.23e5.25 (d,
1H, J¼6.3 Hz), 6.23e6.30 (dd, 1H, J¼6.6 Hz, 15.6 Hz), 6.53e6.59 (d,
Scheme 5. Proposed mechanism.
1H, J¼15.9 Hz), 7.05e7.14 (m, 4H), 7.21e7.27 (m, 4H).
4.2.4. 1,3-Bis(4-methoxyphenyl)prop-2-en-1-ol (1e).17b Pale green
3. Conclusion
solid. 1H NMR (300 MHz, CDCl3)
d
3.79e3.80 (sþs, 6H), 4.71e4.74
(d,1H, J¼6.9 Hz), 6.10e6.18 (dd, 1H, J¼6.9 Hz,15.9 Hz), 6.51e6.56 (d,
1H, J¼15.9 Hz), 6.81e6.91 (m, 4H), 7.29e7.32 (m, 4H).
In summary, a novel metal-free method for the effective cross-
coupling of heteroaryl boronic acids with allylic alcohols has been
developed under catalyst-free reaction conditions. A protocol for
the synthesis of ortho-/ipso-functionalized heteroarenes was
established by using a boronic acid moiety as both a blocking/
directing group in allylation reactions, and the subsequent removal
of the boronic acid moiety via a metal-free proto-deboronation. A
broad range of heteroarene substituted allylic products were ob-
tained in up to 94% yield with moderate to good regioselectivities
and a good functional group tolerance. Further application of this
method for biologically interesting molecules and the elucidation
of reaction mechanism is currently ongoing in our lab.
4.2.5. 1,3-Bis(3-chlorophenyl)prop-2-en-1-ol (1f).17d Light yellow
oil. 1H NMR (400 MHz, CDCl3)
d 3.00 (s, 1H), 5.22e5.24 (d, 1H,
J¼6.2 Hz), 6.20e6.26 (dd, 1H, J¼6.5 Hz, 15.8 Hz), 6.50e6.54 (d, 1H,
J¼15.8 Hz), 7.15e7.18 (m, 3H), 7.20e7.24 (m, 3H), 7.28 (s, 1H), 7.35
(s, 1H); 13C NMR (100 MHz, CDCl3)
d 74.2, 124.5, 124.9, 126.46,
126.54, 127.9, 128.0, 129.6, 129.8, 130.0, 132.2, 134.51, 134.53, 138.1,
144.5.
4.2.6. 1,3-Bis(3-bromophenyl)prop-2-en-1-ol (1g).17c Pale yellow
oil. 1H NMR (300 MHz, CDCl3)
d 2.41 (s, 1H), 5.33e5.35 (d, 1H,
J¼6.0 Hz), 6.29e6.36 (dd, 1H, J¼6.3 Hz, 15.6 Hz), 6.59e6.65 (d, 1H,
4. Experimental section
4.1. General
J¼15.9 Hz), 7.20e7.47 (m, 6H), 7.54e7.60 (d, 2H, J¼16.2 Hz).
4.2.7. 1,3-Di-m-tolylprop-2-en-1-ol (1h).16a Yellow oil. 1H NMR
(300 MHz, CDCl3)
1H, J¼6.3 Hz), 6.30e6.38 (dd, 1H, J¼6.3 Hz, 15.9 Hz), 6.60e6.65 (dd,
1H, J¼0.9 Hz, 15.9 Hz), 7.02e7.10 (m, 2H), 7.17e7.24 (m, 6H).
d
2.19 (s, 1H), 2.31e2.34 (sþs, 6H), 5.29e5.31 (d,
Unless otherwise noted, all reagents were obtained from com-
mercial suppliers and were used without further purification. Tet-
rahydrofuran (THF), toluene and diethyl ether (Et2O) were distilled
from sodium/benzophenone. Dry dichloromethane (CH2Cl2) was
distilled over calcium hydride. N,N-dimethylformate (DMF), di-
methyl sulphoxide (DMSO) were dried over molecular sieves 3 A.
All reactions were carried out under nitrogen atmosphere in oven-
dried glass tube.
4.2.8. 1,3-Bis(3-methoxyphenyl)prop-2-en-1-ol (1i).17d,e Yellow oil.
1H NMR (300 MHz, CDCl3)
d
2.77 (br s, 1H), 3.73e3.74 (sþs, 6H),
ꢀ
5.24e5.26 (d, 1H, J¼6.3 Hz), 6.27e6.34 (dd, 1H, J¼6.3 Hz, 15.6 Hz),
6.55e6.60 (d, 1H, J¼15.9 Hz), 6.74e6.80 (m, 2H), 6.87e6.96 (m, 4H),
7.14e7.25 (m, 2H); 13C NMR (100 MHz, CDCl3)
d 55.01, 55.03, 74.6,
111.7, 111.8, 113.1, 113.4, 118.6, 119.2, 129.4, 129.5, 130.1, 131.8, 138.0,
144.5, 159.62, 159.65.
4.2. Preparation of allylic alcohols16a,17aec
General Procedure (GP1). To a mixture of appropriate acetone
4.2.9. 1,3-Bis(2-chlorophenyl)prop-2-en-1-ol (1j).17e,f Pale yellow
(1.0 equiv), aldehyde (1.0 equiv) in EtOH at 0 ꢀC was added 10% (w/
solid. 1H NMR (300 MHz, CDCl3)
d
2.29e2.30 (d, 1H, J¼3.9 Hz),

X.-D. Li et al. / Tetrahedron 72 (2016) 1873e1880
1877
5.83e5.86 (t, 1H, J¼4.5 Hz), 6.28e6.36 (dd, 1H, J¼6.0 Hz, 15.9 Hz),
7.12e7.18 (m, 4H), 7.25e7.35 (m, 3H), 7.48e7.51 (m, 1H), 7.61e7.63
nmax¼3025, 2925, 1650, 1599, 1507, 1493, 1449, 1261, 967, 746,
698 cmꢂ1. HRMS (APCI): m/z calcd for [MꢂH]þ C19H16S: 275.0889
found: 275.0888.
(dd, 1H, J¼1.2 Hz, 7.6 Hz); 13C NMR (100 MHz, CDCl3)
d 71.2, 126.8,
127.0, 127.3, 127.7, 128.8, 128.9, 129.6, 129.7, 132.3, 132.6, 133.3,
134.8, 139.9.
4.3.2. 3-(1,3-Bis(4-chlorophenyl)allyl)thiophene
(3b). The
title
compound was derived from 1,3-bis(4-chlorophenyl)prop-2-en-1-
ol 1b (42 mg, 0.15 mmol) and 2-thienyl boronic acid 2a (28 mg,
0.22 mmol) in 1 mL of mesitylene following general procedure GP2.
Purification by preparative chromatography using petroleum ether
afforded product 3-(1,3-bis(4-chlorophenyl)allyl)thiophene 3b
(15 mg, 28% yield) as a pale yellow oil. 1H NMR (300 MHz, CDCl3)
4.2.10. 1,3-Bis(2-bromophenyl)prop-2-en-1-ol (1k).17g White solid.
1H NMR (300 MHz, CDCl3)
d
3.33e3.34 (d, 1H, J¼3.6 Hz), 5.70e5.73
(t,1H, J¼4.2 Hz), 6.13e6.20 (dd,1H, J¼6.0 Hz,15.6 Hz), 6.98e7.11 (m,
4H), 7.21e7.26 (t, 1H, J¼7.5 Hz), 7.34e7.36 (d, 1H, J¼7.8 Hz),
7.43e7.46 (m, 2H), 7.53e7.55 (d, 1H, J¼7.8 Hz).
d
4.86e4.89 (d, 1H, J¼7.2 Hz), 6.27e6.33 (d, 1H, J¼15.9 Hz),
4.2.11. 1,3-Di-o-tolylprop-2-en-1-ol (1l).16a Pale yellow solid. 1H
NMR (400 MHz, CDCl3) d 2.30 (s, 3H), 2.34 (s, 3H), 5.49e5.51 (d, 1H,
6.51e6.59 (dd, 1H, J¼7.2 Hz, 15.6 Hz), 6.88e6.89 (d, 1H, J¼4.8 Hz),
6.95e6.96 (d, 1H, J¼2.4 Hz), 7.15e7.17 (m, 2H), 7.23e7.31 (m, 7H);
J¼6.3 Hz), 6.15e6.21 (dd, 1H, J¼6.4 Hz, 15.7 Hz),; 6.80e6.84 (d, 1H,
13C NMR (100 MHz, CDCl3)
d 49.4, 121.9, 126.2, 127.7, 128.0, 128.83,
J¼15.7 Hz), 7.10e7.22 (m, 6H), 7.36e7.38 (m, 1H), 7.48e7.50 (d, 1H,
128.85, 129.8, 130.3, 132.4, 132.6, 133.2, 135.6, 141.5, 143.6. FTIR
J¼7.2 Hz); 13C NMR (100 MHz, CDCl3)
d
19.3, 19.8, 72.1, 125.87,
(KBr): nmax¼3025, 1599, 1493, 1449, 1428, 969, 745, 732, 699 cmꢂ1
.
125.93, 126.1, 126.4, 127.65, 127.67, 128.5, 130.3, 130.6, 132.2, 135.3,
135.6, 135.8, 140.8.
HRMS (APCI): m/z calcd for [MþH]þ C19H14Cl2S: 345.0266 found:
345.0267.
4.2.12. 1,3-Bis(2-fluorophenyl)prop-2-en-1-ol (1m).17e Pale yellow
4.3.3. 3-(1,3-Bis(4-bromophenyl)allyl)thiophene
(3c). The
title
oil. 1H NMR (300 MHz, CDCl3)
d
2.77e2.78 (d, 1H, J¼4.2 Hz),
compound was derived from 1,3-bis(4-bromophenyl)prop-2-en-1-
ol 1c (55 mg, 0.15 mmol) and 2-thienyl boronic acid 2a (28 mg,
0.22 mmol) in 1 mL of mesitylene following general procedure
GP2. Purification by preparative chromatography using petroleum
ether afforded product 3-(1,3-bis(4-bromophenyl)allyl)thiophene
3c (45 mg, 69% yield) as a pale yellow oil. 1H NMR (300 MHz,
5.62e5.65 (t, 1H, J¼4.8 Hz), 6.41e6.48 (dd, 1H, J¼6.3 Hz, 15.9 Hz),
6.79e6.85 (d, 1H, J¼15.9 Hz), 6.97e7.04 (m, 3H), 7.11e7.23 (m, 3H),
7.35e7.40 (t, 1H, J¼7.5 Hz), 7.45e7.50 (t, 1H, J¼7.2 Hz); 13C NMR
(100 MHz, CDCl3)
d 69.16, 69.19, 123.1, 123.2, 124.10, 124.13, 124.3,
124.4, 124.47, 124.50, 127.71, 127.75, 129.07, 129.15, 129.3, 129.4,
129.7, 129.8, 132.77, 132.82, 158.8, 159.2, 161.2, 161.7.
CDCl3)
d
4.83e4.86 (d, 1H, J¼7.2 Hz), 6.25e6.31 (d, 1H, J¼15.9 Hz),
6.51e6.59 (dd, 1H, J¼7.5 Hz, 15.6 Hz), 6.86e6.88 (d, 1H, J¼1.5 Hz,
5.1 Hz), 6.94e6.95 (m, 1H), 7.08e7.11 (m, 2H), 7.19e7.22 (m, 2H),
7.27e7.29 (dd, 1H, J¼3.0 Hz, 5.1 Hz), 7.39e7.45 (m, 4H); 13C NMR
4.2.13. 1,3-Di(thiophen-2-yl)prop-2-en-1-ol (1n).17h Red-violet oil.
1H NMR (400 MHz, CDCl3)
d
2.22e2.23 (d, 1H, J¼4.4 Hz), 5.56e5.59
(t,1H, J¼5.2 Hz), 6.25e6.31 (dd,1H, J¼6.4 Hz,15.6 Hz), 6.83e6.87 (d,
1H, J¼15.6 Hz), 6.96e7.03 (m, 4H), 7.17e7.18 (d, 1H, J¼5.0 Hz),
(126 MHz, DMSO-d6) d 48.7, 119.5, 120.3, 121.5, 125.0, 126.5, 127.7,
128.3, 129.2, 130.1, 131.4, 132.9, 136.0, 142.9, 143.6. FTIR (KBr):
nmax¼2251, 2124, 1660, 1487, 1056, 1028, 823, 760 cmꢂ1. HRMS
(ESI): m/z calcd for [MþH]þ C19H14Br2S: 432.9072 found:
432.9078.
7.28e7.29 (d,1H, J¼4.9 Hz); 13C NMR (100 MHz, CDCl3)
d 70.6,124.3,
124.5, 124.9, 125.4, 126.5, 126.9, 127.5, 130.0, 141.3, 146.6.
4.2.14. (3-Methoxyprop-1-ene-1,3-diyl)dibenzene (6).17i The title
compound was prepared according to the literature as pale yellow
4.3.4. 3-(1,3-Di-p-tolylallyl)thiophene (3d). The title compound
was derived from 1,3-di-p-tolylprop-2-en-1-ol 1d (36 mg,
0.15 mmol) and 2-thienyl boronic acid 2a (28 mg, 0.22 mmol) in
1 mL of mesitylene following general procedure GP2. Purification
by preparative chromatography using petroleum ether afforded
product 3-(1,3-di-p-tolylallyl)thiophene 3d (27 mg, 59% yield) as
oil. 1H NMR (300 MHz, CDCl3)
d 3.37 (s, 3H), 4.77e4.80 (d, 1H,
J¼6.9 Hz), 6.24e6.31 (dd, 1H, J¼6.9 Hz, 15.9 Hz), 6.59e6.65 (d, 1H,
J¼15.9 Hz), 7.20e7.37 (m, 10H); 13C NMR (126 MHz, CDCl3)
d 56.6,
84.5, 126.7, 127.0, 127.9, 128.7, 130.3, 131.6, 136.7, 141.2.
a brownish yellow oil. 1H NMR (400 MHz, CDCl3)
d
2.31e2.32 (sþs,
4.3. Preparation of allylation products
6H), 4.83e4.85 (d, 1H, J¼7.6 Hz), 6.32e6.36 (d, 1H, J¼16.0 Hz),
6.52e6.58 (dd, 1H, J¼7.6 Hz, 15.6 Hz), 6.90e6.91 (d, 1H, J¼5.2 Hz),
6.940e6.944 (d, 1H, J¼1.6 Hz), 7.08e7.12 (m, 6H), 7.24e7.26 (m,
General Procedure (GP2). To
a mixture of allylic alcohol
(1.0 equiv) and heteroarene boronic acids (1.5 equiv) in a sealed
tube under nitrogen atmosphere was added the solvent. The mix-
ture was heated at 120 ꢀC and stirred until TLC indicated the
completion of the reaction. The solution was then cooled to room
temperature. The mixture was co-evaporated with methanol under
vacuum and the residue was purified by preparative chromatog-
raphy to afford the product as a mixture of two inseparable isomers.
3H); 13C NMR (100 MHz, CDCl3)
d 21.0, 21.1, 49.6, 121.4, 125.5, 126.2,
128.16, 128.21, 129.17, 129.19, 130.6, 131.3, 134.5, 136.0, 137.0, 140.3,
144.6. FTIR (KBr): nmax¼3022, 2921, 1511, 1453, 969, 802, 501 cmꢂ1
.
HRMS (APCI): m/z calcd for [MþH]þ C21H20S: 305.1358 found:
305.1359.
4.3.5. 3-(1,3-Bis(4-methoxyphenyl)allyl)thiophene (3e). The title
compound was derived from 1,3-bis(4-methoxyphenyl)prop-2-en-
1-ol 1e (50 mg, 0.18 mmol) and 2-thienyl boronic acid 2a (35 mg,
0.27 mmol) in 1 mL of mesitylene following general procedure GP2.
Purification by preparative chromatography using petroleum ether/
ethyl acetate (50/1) afforded product 3-(1,3-bis(4-methoxyphenyl)
allyl)thiophene 3e (35 mg, 58% yield) as a yellow oil. 1H NMR
4.3.1. 3-(1,3-Diphenylallyl)thiophene (3a). The title compound was
derived from 1,3-diphenylprop-2-en-1-ol 1a (31 mg, 0.15 mmol)
and 2-thienyl boronic acid 2a (28 mg, 0.22 mmol) in 1 mL of
mesitylene following general procedure GP2. Purification by pre-
parative chromatography using petroleum ether afforded the
product 3-(1,3-diphenylallyl)thiophene 3a (30 mg, 71% yield) as
(400 MHz, CDCl3)
d
3.78 (s, 6H), 4.82e4.84 (d, 1H, J¼7.4 Hz),
a dark yellow oil. 1H NMR (300 MHz, CDCl3)
d
4.89e4.91 (d, 1H,
6.28e6.32 (d, 1H, J¼15.8 Hz), 6.43e6.49 (dd, 1H, J¼7.6 Hz, 15.6 Hz),
J¼7.5 Hz), 6.35e6.41 (d, 1H, J¼15.9 Hz), 6.58e6.66 (dd, 1H,
6.81e6.86 (m, 5H), 6.90e6.94 (m, 2H), 7.14e7.16 (m, 2H), 7.20e7.23
J¼7.5 Hz, 15.9 Hz), 6.91e6.96 (m, 2H), 7.19e7.35 (m, 12H); 13C NMR
(m,1H), 7.28e7.31 (m, 2H); 13C NMR (100 MHz, CDCl3)
d 49.3, 55.38,
(75 MHz, CDCl3)
d
50.2, 121.8, 125.8, 126.5, 126.8, 127.5, 128.3,
55.41, 114.0, 114.1, 121.5, 125.7, 127.6, 128.3, 129.4, 130.2, 130.5, 135.7,
128.6, 128.70, 128.73, 131.2, 132.4, 137.4, 143.4, 144.5. FTIR (KBr):
145.0, 158.4, 159.1. FTIR (KBr): nmax¼2954, 2834, 1607, 1510, 1248,

1878
X.-D. Li et al. / Tetrahedron 72 (2016) 1873e1880
1175, 1034, 969, 831 cmꢂ1. HRMS (APCI): m/z calcd for [MþH]þ
159.91. FTIR (KBr): nmax¼2958, 2834, 1596, 1260, 1151, 1042, 970,
777, 688 cmꢂ1. HRMS (APCI): m/z calcd for [MþH]þ C21H20O2S:
337.1257 found: 337.1256.
C21H20O2S: 337.1257 found: 337.1256.
4.3.6. 3-(1,3-Bis(3-chlorophenyl)allyl)thiophene (3f). The title com-
pound was derived from 1,3-bis(3-chlorophenyl)prop-2-en-1-ol 1f
(48 mg, 0.17 mmol) and 2-thienyl boronic acid 2a (33 mg,
0.26 mmol) in 1 mL of mesitylene following general procedure GP2.
Purification by preparative chromatography using petroleum ether
afforded product 3-(1,3-bis(3-chlorophenyl)allyl)thiophene 3f
(55 mg, 94% yield) as a brownish yellow oil. 1H NMR (300 MHz,
4.3.10. 3-(1,3-Bis(2-chlorophenyl)allyl)thiophene (3j). The title
compound was derived from 1,3-bis(2-chlorophenyl)prop-2-en-1-
ol 1j (47 mg, 0.17 mmol) and 2-thienyl boronic acid 2a (33 mg,
0.26 mmol) in 1 mL of mesitylene following general procedure GP2.
Purification by preparative chromatography using petroleum ether
afforded product 3-(1,3-bis(2-chlorophenyl)allyl)thiophene 3j
(13 mg, 25% yield) as a yellow oil. 1H NMR (300 MHz, CDCl3)
CDCl3)
d
4.87e4.90 (d, 1H, J¼7.5 Hz), 6.29e6.34 (d, 1H, J¼15.9 Hz),
6.55e6.63 (dd, 1H, J¼7.5 Hz, 15.7 Hz), 6.89e6.91 (d, 1H, J¼4.9 Hz),
d
5.45e5.48 (d, 1H, J¼6.8 Hz), 6.50e6.58 (dd, 1H, J¼7.4 Hz, 15.5 Hz),
6.98 (s,1H), 7.11e7.13 (d,1H, J¼5.5 Hz), 7.22e7.31 (m, 11H); 13C NMR
6.84e6.86 (d, 1H, J¼4.7 Hz), 6.96e7.00 (m, 1H), 7.18e7.26 (m, 6H),
(126 MHz, CDCl3) d 49.8, 122.1, 124.8, 126.3, 126.4, 126.7, 127.1, 127.6,
7.32e7.34 (m, 2H), 7.39e7.42 (m, 1H), 7.53e7.56 (m, 1H); 13C NMR
128.0, 128.6, 129.9, 130.0, 130.4, 133.0, 134.6, 134.7, 138.9, 143.2,
145.0. FTIR (KBr): nmax¼2923, 2852, 1593, 1570, 1473, 1428, 1079,
778, 693 cmꢂ1. HRMS (APCI): m/z calcd for [MꢂH]þ C19H14Cl2S:
343.0110 found: 343.0108.
(100 MHz, CDCl3) d 46.0, 122.2, 124.7, 125.8, 126.9, 127.0, 127.19,
127.23, 128.4, 128.66, 128.73, 129.81, 129.83, 130.0, 133.4, 135.3,
140.5, 142.8, 145.9. FTIR (KBr): nmax¼2923, 2852, 1470, 1441, 1034,
967, 751, 696 cmꢂ1. HRMS: m/z calcd for [MþH]þ C19H14Cl2S:
345.0266 found: 345.0265.
4.3.7. 3-(1,3-Bis(3-bromophenyl)allyl)thiophene
(3g). The
title
compound was derived from 1,3-bis(3-bromophenyl)prop-2-en-1-
ol 1g (75 mg, 0.20 mmol) and 2-thienyl boronic acid 2a (39 mg,
0.30 mmol) in 1 mL of mesitylene following general procedure GP2.
Purification by preparative chromatography using petroleum ether
afforded product 3-(1,3-bis(3-bromophenyl)allyl)thiophene 3g
(22 mg, 25% yield) as a yellow oil. 1H NMR (400 MHz, CDCl3)
4.3.11. 3-(1,3-Bis(2-bromophenyl)allyl)thiophene (3k). The title
compound was derived from 1,3-bis(2-bromophenyl)prop-2-en-1-
ol 1k (61 mg, 0.17 mmol) and 2-thienyl boronic acid 2a (32 mg,
0.25 mmol) in 1 mL of mesitylene following general procedure GP2.
Purification by preparative chromatography using petroleum ether
afforded product 3-(1,3-bis(2-bromophenyl)allyl)thiophene 3k
(9 mg, 12% yield) as a pale yellow oil. 1H NMR (300 MHz, CDCl3)
d
4.85e4.87 (d, 1H, J¼7.2 Hz), 6.27e6.31 (d, 1H, J¼15.8 Hz),
6.54e6.60 (dd, 1H, J¼7.3 Hz, 15.4 Hz), 6.88e6.89 (d, 1H, J¼4.3 Hz),
6.97 (s,1H), 7.17e7.19 (m, 3H), 7.25e7.30 (m, 2H), 7.33e7.38 (m, 3H),
d
5.44e5.46 (d, 1H, J¼5.4 Hz), 6.44e6.54 (m, 1H), 6.69e6.75 (d, 1H,
J¼16.2 Hz), 6.81e6.87 (m, 1H), 6.93e7.01 (m, 2H), 7.08e7.13 (m,
7.52 (s, 1H); 13C NMR (100 MHz, CDCl3)
d 49.6, 122.0, 122.78, 122.83,
2H), 7.23e7.32 (m, 5H), 7.51e7.54 (m, 2H), 7.59e7.61 (m, 1H); 13C
125.1, 126.2, 127.1, 127.9, 129.2,129.9, 130.1, 130.2, 130.4, 130.5, 131.4,
132.9, 139.1, 143.0, 145.2. FTIR (KBr): nmax¼2957, 2925, 1590, 1564,
1530, 1472, 1425, 1071, 776 cmꢂ1. HRMS (ESI): m/z calcd for [MþH]þ
C19H14Br2S: 432.9085 found: 432.9079.
NMR (126 MHz, CDCl3) d 48.9, 122.3, 123.8, 124.8, 125.9, 127.3, 127.6,
127.8, 128.3,128.4,128.9,130.1, 131.2, 133.0, 133.3,133.9,137.3,142.1,
142.7. FTIR (KBr): nmax¼2921, 2851, 1633, 1467, 1023, 749 cmꢂ1
.
HRMS (APCI): m/z calcd for [MþH]þ C19H14Br2S: 432.9256 found:
432.9255.
4.3.8. 3-(1,3-Di-m-tolylallyl)thiophene (3h). The title compound
was derived from 1,3-di-m-tolylprop-2-en-1-ol 1h (45 mg,
0.19 mmol) and 2-thienyl boronic acid 2a (36 mg, 0.28 mmol) in
1 mL of mesitylene following general procedure GP2. Purification
by preparative chromatography using petroleum ether afforded
product 3-(1,3-di-m-tolylallyl)thiophene 3h (37 mg, 63% yield) as
4.3.12. 3-(1,3-Di-o-tolylallyl)thiophene (3l). The title compound
was derived from 1,3-di-o-tolylprop-2-en-1-ol 1l (35 mg,
0.15 mmol) and 2-thienyl boronic acid 2a (28 mg, 0.22 mmol) in
1 mL of mesitylene following general procedure GP2. Purification
by preparative chromatography using petroleum ether afforded
product 3-(1,3-di-o-tolylallyl)thiophene 3l (29 mg, 65% yield) as
a yellow oil. 1H NMR (400 MHz, CDCl3)
d
2.32 (sþs, 6H), 4.84e4.86
(d, 1H, J¼7.7 Hz), 6.33e6.37 (d, 1H, J¼15.8 Hz), 6.57e6.63 (dd, 1H,
J¼7.7 Hz, 15.7 Hz), 6.91e6.92 (dd, 1H, J¼1.1 Hz, 4.9 Hz), 6.95e6.96
(m, 1H), 7.03e7.06 (m, 4H), 7.16e7.20 (m, 4H), 7.24e7.26 (dd, 1H,
a pale yellow oil. 1H NMR (400 MHz, CDCl3)
d 2.24 (s, 3H), 2.34 (s,
3H), 5.10e5.12 (d, 1H, J¼5.6 Hz), 6.48e6.49 (m, 1H), 6.89e6.92 (m,
2H), 7.11e7.17 (m, 8H), 7.26e7.28 (m, 1H), 7.45e7.47 (m, 1H); 13C
J¼2.9 Hz, 4.9 Hz); 13C NMR (126 MHz, CDCl3)
d
21.5, 21.6, 50.2,121.6,
NMR (100 MHz, CDCl3) d 19.7, 19.9, 46.5, 121.8, 125.6, 125.8, 126.2,
123.6, 125.5, 125.7, 127.2, 127.5, 128.2, 128.3, 128.6, 129.2, 131.0,
132.2, 137.3, 138.2, 138.3, 143.3, 144.6. FTIR (KBr): nmax¼2921, 2857,
1604, 1488, 867, 778, 692 cmꢂ1. HRMS (APCI): m/z calcd for [MþH]þ
C21H20S: 305.1358 found: 305.1357.
126.3, 126.7, 127.4, 128.2, 128.5, 129.2, 130.3, 130.7, 133.3, 135.4,
136.2, 136.6, 141.5, 144.1. FTIR (KBr): nmax¼2924, 1487, 1460, 1379,
970, 748 cmꢂ1. HRMS (APCI): m/z calcd for [MþH]þ C21H20S:
305.1358 found: 305.1359.
4.3.9. 3-(1,3-Bis(3-methoxyphenyl)allyl)thiophene (3i). The title
compound was derived from 1,3-bis(3-methoxyphenyl)prop-2-en-
1-ol 1i (53 mg, 0.20 mmol) and 2-thienyl boronic acid 2a (38 mg,
0.29 mmol) in 1 mL of mesitylene following general procedure
GP2. Purification by preparative chromatography using petroleum
ether/ethyl acetate (50/1) afforded product 3-(1,3-bis(3-
methoxyphenyl)allyl)thiophene 3i (45 mg, 68% yield) as a yellow
4.3.13. 3-(1,3-Bis(2-fluorophenyl)allyl)thiophene (3m). The title
compound was derived from 1,3-bis(2-fluorophenyl)prop-2-en-1-
ol 1m (47 mg, 0.19 mmol) and 2-thienyl boronic acid 2a (37 mg,
0.29 mmol) in 1 mL of mesitylene following general procedure GP2.
Purification by preparative chromatography using petroleum ether/
ethyl acetate (50/1) afforded product 3-(1,3-bis(2-fluorophenyl)al-
lyl)thiophene 3m (28 mg, 53% yield) as a pale yellow oil. 1H NMR
oil. 1H NMR (400 MHz, CDCl3)
d
3.76e3.78 (sþs, 6H), 4.85e4.87 (d,
(300 MHz, CDCl3)
J¼16.2 Hz), 6.65e6.71 (m, 1H), 6.73e7.13 (m, 5H), 7.20e7.28 (m,
5H), 7.43e7.47 (m, 1H); 13C NMR (100 MHz, CDCl3)
43.4, 43.5,
d
5.23e5.25 (d, 1H, J¼7.5 Hz), 6.54e6.59 (d, 1H,
1H, J¼7.6 Hz), 6.34e6.38 (d, 1H, J¼15.8 Hz), 6.57e6.63 (dd, 1H,
J¼7.6 Hz, 15.6 Hz), 6.76e6.80 (m, 3H), 6.83e6.85 (m, 1H),
6.90e6.97 (m, 4H), 7.19e7.25 (m, 3H); 13C NMR (100 MHz, CDCl3)
d
115.66, 115.75, 115.9, 116.0, 121.8, 124.2, 124.37, 124.41, 124.6, 125.4,
125.9, 127.0, 127.7, 128.1, 128.46, 128.54, 128.8, 128.9, 129.8, 130.0,
133.4, 133.5, 143.0, 159.1, 159.4, 161.6, 161.8. FTIR (KBr): nmax¼2924,
d
50.1, 55.28, 55.32, 111.7, 111.8, 113.2, 114.5, 119.1, 120.9, 121.7,
125.8, 128.2, 129.60, 129.63, 131.1, 132.4, 138.8, 144.1, 144.9, 159.89,

X.-D. Li et al. / Tetrahedron 72 (2016) 1873e1880
1879
1584, 1487, 1456, 1231, 969, 754 cmꢂ1. HRMS (APCI): m/z calcd for
[MꢂH]þ C19H14F2S: 311.0701 found: 311.0700.
procedure GP2. The mixture was heated at 100 ꢀC and stirred until
TLC indicated the completion of the reaction. Purification by pre-
parative chromatography using petroleum ether/ethyl acetate (50/
1) afforded product 2-(1,3-diphenylallyl)-1H-pyrrole 4d (20 mg,
4.3.14. 2,20-(3-(Thiophen-3-yl)prop-1-ene-1,3-diyl)dithiophene
(3n). The title compound was derived from 1,3-di(thiophen-2-yl)
prop-2-en-1-ol 1n (62 mg, 0.28 mmol) and 2-thienyl boronic acid
2a (53 mg, 0.41 mmol) in 1 mL of mesitylene following general
procedure GP2. Purification by preparative chromatography using
petroleum ether afforded product 2,20-(3-(thiophen-3-yl)prop-1-
ene-1,3-diyl)dithiophene 3n (28 mg, 35% yield) as a pale yellow
50% yield) as a brown oil. 1H NMR (500 MHz, CDCl3)
d 4.86e4.87 (d,
1H, J¼5.2 Hz), 5.96 (s, 1H), 6.17 (s, 1H), 6.40e6.44 (dd, 1H, J¼2.1 Hz,
15.7 Hz), 6.56e6.61 (m, 1H), 6.70 (s, 1H), 7.23e7.37 (m, 11H), 7.85 (s,
1H); 13C NMR (126 MHz, CDCl3)
d
48.2, 106.8, 108.5, 117.3, 126.4,
127.0, 127.5, 128.5, 128.6, 128.8, 131.1, 131.3, 133.1, 137.1, 142.1.
oil. 1H NMR (500 MHz, CDCl3)
d
5.11e5.13 (d, 1H, J¼7.3 Hz),
4.3.19. 2-(1,3-Diphenylallyl)benzo[b]thiophene
(4e).9f The
title
6.44e6.48 (m, 1H), 6.56e6.59 (d, 1H, J¼14.0 Hz), 6.84e6.85 (d, 1H,
J¼3.5 Hz), 6.91e6.96 (m, 6H), 7.00e7.01 (dd, 1H, J¼1.1 Hz, 5.0 Hz),
7.06e7.07 (dd, 1H, J¼0.9 Hz, 1.9 Hz), 7.13 (s, 1H), 7.19e7.23 (m, 2H),
7.28e7.29 (dd, 1H, J¼3.0 Hz, 5.0 Hz); 13C NMR (126 MHz, CDCl3)
compound was derived from 1,3-diphenylprop-2-en-1-ol 1a
(31 mg, 0.15 mmol) and benzo[b]2-thienyl boronic acid 2f (39 mg,
0.22 mmol) in 1 mL of mesitylene following general procedure GP2.
Purification by preparative chromatography using petroleum ether
afforded product 2-(1,3-diphenylallyl)benzo[b]thiophene 4e
(40 mg, 80% yield) as a brownish yellow oil. 1H NMR (400 MHz,
d
44.9, 121.8, 124.3, 124.4, 124.6, 125.2, 126.8, 127.4, 127.7, 131.2,
142.0, 143.4, 146.8. FTIR (KBr): nmax¼2922, 2851, 1633, 1433, 1229,
1078, 1040, 954, 693 cmꢂ1. HRMS (APCI): m/z calcd for [MþH]þ
C15H12S3: 289.0174 found: 289.0171.
CDCl3)
d
5.19e5.20 (d, 1H, J¼7.1 Hz), 6.33e6.37 (d, 1H, J¼15.9 Hz),
6.68e6.74 (dd, 1H, J¼7.2 Hz, 15.8 Hz), 7.10 (s, 1H), 7.19e7.35 (m,
12H), 7.60e7.62 (m, 1H), 7.82e7.84 (d, 1H, J¼7.4 Hz); 13C NMR
4.3.15. 2-(1,3-Diphenylallyl)thiophene (4a).9f The title compound
was derived from 1,3-diphenylprop-2-en-1-ol 1a (31 mg,
0.15 mmol) and 3-thienyl boronic acid 2b (28 mg, 0.22 mmol) in
1 mL of mesitylene following general procedure GP2. Purification
by preparative chromatography using petroleum ether afforded the
product 2-(1,3-diphenylallyl)thiophene 4a (23 mg, 56% yield) as
(100 MHz, CDCl3) d 48.7, 122.8, 123.0, 123.8, 124.1, 124.4, 126.5,
126.9, 127.6, 128.66, 128.69, 128.74, 131.4, 131.7, 137.2, 138.2, 138.4,
140.9, 142.1.
4.3.20. 3-(1,3-Diphenylallyl)benzo[b]thiophene (4f). The title com-
pound was derived from 1,3-diphenylprop-2-en-1-ol 1a (31 mg,
0.15 mmol) and benzo[b]3-thienyl boronic acid 2g (40 mg,
0.22 mmol) in 1 mL of mesitylene following general procedure GP2.
Purification by preparative chromatography using petroleum ether
afforded product 3-(1,3-diphenylallyl)benzo[b]thiophene 4f
(41 mg, 82% yield) as a yellow oil. 1H NMR (400 MHz, CDCl3)
a yellow oil. 1H NMR (300 MHz, CDCl3)
d
5.05e5.07 (d,1H, J¼7.5 Hz),
6.41e6.47 (d, 1H, J¼15.9 Hz), 6.60e6.68 (dd, 1H, J¼7.5 Hz, 15.9 Hz),
6.81e6.96 (m, 1H), 7.18e7.38 (m, 11H); 13C NMR (100 MHz, CDCl3)
d
49.9, 124.5, 125.2, 126.6, 126.9, 127.0, 127.6, 128.4, 128.67, 128.75,
131.4, 132.1, 137.1, 143.3, 147.8.
d
5.10e5.12 (d, 1H, J¼7.6 Hz), 6.49e6.53 (d, 1H, J¼15.8 Hz),
4.3.16. 2-(1,3-Diphenylallyl)furan (4b).9f The title compound was
derived from 1,3-diphenylprop-2-en-1-ol 1a (31 mg, 0.15 mmol)
and 3-furanyl boronic acid 2c (25 mg, 0.22 mmol) in 1 mL of
mesitylene following general procedure GP2. Purification by pre-
parative chromatography using petroleum ether afforded product
2-(1,3-diphenylallyl)furan 4b (13 mg, 32% yield) as a pale yellow oil.
6.66e6.72 (dd,1H, J¼7.6 Hz,15.8 Hz), 7.04 (s,1H), 7.20e7.31 (m, 8H),
7.34e7.40 (m, 5H), 7.64e7.66 (d, 1H, J¼7.7 Hz), 7.71e7.73 (d, 1H,
J¼7.8 Hz); 13C NMR (100 MHz, CDCl3)
d 50.4, 121.8, 122.2, 123.2,
123.8, 124.2, 126.5, 127.2, 127.6, 128.4, 128.6, 128.7, 131.2, 131.9,
136.9, 139.87, 139.89, 142.5, 148.6. FTIR (KBr): nmax¼3026, 2925,
1599, 1493, 1452, 1099, 967, 746, 699 cmꢂ1. HRMS (APCI): m/z calcd
for [MꢂH]þ C23H18S: 325.1045 found: 325.1045.
1H NMR (400 MHz, CDCl3)
d
4.89e4.91 (d, 1H, J¼7.4 Hz), 6.09e6.10
(d, 1H, J¼3.1 Hz), 6.32e6.34 (dd, 1H, J¼1.9 Hz, 2.9 Hz), 6.38e6.42 (d,
1H, J¼15.9 Hz), 6.54e6.60 (dd, 1H, J¼7.4 Hz, 15.8 Hz), 7.19e7.38 (m,
4.3.21. 2-(1,3-Diphenylallyl)benzofuran (4g).9f The title compound
was derived from 1,3-diphenylprop-2-en-1-ol 1a (31 mg,
0.15 mmol) and benzofuran-2-ylboronic acid 2h (36 mg,
0.22 mmol) in 1 mL of mesitylene following general procedure GP2.
Purification by preparative chromatography using petroleum ether
afforded product 2-(1,3-diphenylallyl)benzofuran 4g (27 mg, 59%
12H); 13C NMR (100 MHz, CDCl3)
d 48.5, 106.9, 110.3, 126.5, 127.0,
127.6, 128.4, 128.65, 128.74, 129.9, 131.8, 137.2, 141.3, 142.0, 156.3.
4.3.17. 1-(1,3-Diphenylallyl)-1H-pyrazole (4c).17j The title com-
pound was derived from 1,3-diphenylprop-2-en-1-ol 1a (31 mg,
0.15 mmol) and (1-(tert-butoxycarbonyl)-1H-pyrazol-5-yl)boronic
acid 2d (25 mg, 0.22 mmol) in 1 mL of water following general
procedure GP2. The mixture was heated at 100 ꢀC and stirred until
TLC indicated the completion of the reaction. Purification by pre-
parative chromatography using petroleum ether/ethyl acetate (50/
1) afforded product 1-(1,3-diphenylallyl)-1H-pyrazole 4c (28 mg,
72% yield) as a brownish yellow oil. 1H NMR (500 MHz, CDCl3)
yield) as a yellow oil. 1H NMR (300 MHz, CDCl3)
d 4.98e5.00 (d, 1H,
J¼7.3 Hz), 6.44e6.49 (d, 1H, J¼15.7 Hz), 6.61e6.69 (dd, 1H, J¼7.3 Hz,
15.8 Hz), 7.09e7.14 (t, 1H, J¼7.5 Hz), 7.20e7.34 (m, 12H), 7.45e7.48
(d, 1H, J¼8.2 Hz); 13C NMR (100 MHz, CDCl3)
d 45.1, 111.5, 120.7,
122.4, 122.9, 124.3, 126.4, 126.9, 127.5, 128.4, 128.6, 128.7, 130.7,
131.5, 137.1, 141.7, 142.7, 155.8.
d
6.18e6.19 (d, 1H, J¼7.0 Hz), 6.30e6.31 (t, 1H, J¼2.2 Hz), 6.43e6.46
4.3.22. 3-(1,3-Diphenylallyl)benzofuran (4h). The title compound
was derived from 1,3-diphenylprop-2-en-1-ol 1a (31 mg,
0.15 mmol) and benzofuran-3-ylboronic acid 2i (36 mg, 0.22 mmol)
in 1 mL of mesitylene following general procedure GP2. Purification
by preparative chromatography using petroleum ether afforded
product 3-(1,3-diphenylallyl)benzofuran 4h (30 mg, 64% yield) as
(d, 1H, J¼15.9 Hz), 6.70e6.74 (dd, 1H, J¼7.0 Hz, 15.9 Hz), 7.22e7.27
(m, 3H), 7.29e7.32 (m, 3H), 7.34e7.40 (m, 4H), 7.46e7.47 (d, 1H,
J¼2.3 Hz), 7.602e7.605 (d, 1H, J¼1.5 Hz); 13C NMR (126 MHz, CDCl3)
d
67.6, 105.7, 126.8, 127.36, 127.43, 128.16, 128.19, 128.56, 128.63,
128.8, 133.8, 136.1, 139.5, 139.7.
a pale yellow oil. 1H NMR (400 MHz, CDCl3)
d 5.01e5.03 (d, 1H,
4.3.18. 2-(1,3-Diphenylallyl)-1H-pyrrole (4d).9f The title compound
was derived from 1,3-diphenylprop-2-en-1-ol 1a (31 mg,
0.15 mmol) and (1-(tert-butoxycarbonyl)-1H-pyrrol-2-yl)boronic
acid 2e (46 mg, 0.22 mmol) in 1 mL of water following general
J¼7.4 Hz), 6.45e6.49 (m, 2H), 6.61e6.67 (dd, 1H, J¼7.4 Hz, 15.8 Hz),
7.18e7.23 (m, 3H), 7.27e7.34 (m, 7H), 7.37e7.42 (m, 3H), 7.48e7.50
(m, 1H); 13C NMR (126 MHz, CDCl3)
d
48.9, 104.1, 111.3, 120.8, 122.7,
123.8, 126.6, 127.3, 127.8, 128.5, 128.66, 128.69, 128.8, 129.2, 132.4,

1880
X.-D. Li et al. / Tetrahedron 72 (2016) 1873e1880
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7294.
137.0, 140.6, 155.2, 159.4. FTIR (KBr): nmax¼3027, 2920, 1582, 1493,
1453, 1254, 965, 750, 698 cmꢂ1. HRMS (APCI): m/z calcd for [MþH]þ
C23H18O: 311.1430 found: 311.1429.
4.3.23. 2-(3-(3-Chlorophenyl)-1-(p-tolyl)allyl)thiophene (10) and 2-
(1-(3-chlorophenyl)-3-(p-tolyl)allyl)thiophene (11). The title com-
pounds were derived from 3-(3-chlorophenyl)-1-(p-tolyl)prop-2-
en-1-ol 8 (46 mg, 0.18 mmol) and 3-thienyl boronic acid 2b
(34 mg, 0.27 mmol) in 1.2 mL of mesitylene following general
procedure GP2. Purification by preparative chromatography using
petroleum ether afforded the products 2-(3-(3-chlorophenyl)-1-(p-
tolyl)allyl)thiophene 10 and 2-(1-(3-chlorophenyl)-3-(p-tolyl)allyl)
thiophene 11 as an inseparable mixture (23 mg, 41% yield, 10:11
ꢁ
5. (a) Gawande, M. B.; Bonifacio, V. D.; Luque, R.; Branco, P. S.; Varma, R. S.
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d
2.32e2.34 (sþs,
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2012, 1085; (h) Bar-luenga, J.; Tomas-Gamasa, M.; Aznar, F.; Valdes, C. Nat.
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3H), 5.01e5.03 (d, 1H, J¼7.5 Hz), 6.33e6.43 (m, 1H), 6.49e6.57 (dd,
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J¼7.6 Hz, 15.7 Hz), 6.80e6.82 (m, 1H), 6.93e6.97 (m, 1H), 7.10e7.22
(m, 7H), 7.26e7.28 (m, 1H), 7.35 (s, 1H); 13C NMR (126 MHz, CDCl3)
8. For 2-thiophene/2-benzothiophene allylations using thiophene boronic acids
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d
21.2, 21.3, 49.4, 49.5, 124.5, 124.7, 124.8, 125.2, 125.4, 126.45,
126.51, 126.6, 126.9, 127.0, 127.2, 127.5, 128.2, 128.5, 129.4, 129.5,
129.86, 129.91, 130.0, 130.2, 131.8, 133.8, 134.1, 134.5, 134.6, 136.8,
137.7, 139.1, 139.9, 145.5, 146.9, 147.5. FTIR (KBr): nmax¼3023, 2920,
1594, 1511, 1473, 965, 783, 698 cmꢂ1. HRMS (APCI): m/z calcd for
[MþH]þ C20H17ClS: 325.0812 found: 325.0810.
Acknowledgements
We gratefully acknowledge Prof. Sheng-Mei Lu (Dalian Institute
of Chemical Physics, Chinese Academy of Sciences), Prof. Li-Wen Xu
(Hangzhou Normal University) and Prof. Hai-Feng Du (Institute of
Chemistry, Chinese Academy of Sciences) for their generous sup-
ports in providing some allylic alcohols. This work was supported
by the National Natural Science Foundation of China (Nos.
21502201 and 21372224), Beijing Natural Science Foundation (No.
2162049) and Institute of Chemistry, Chinese Academy of Sciences
(Outstanding Young Talent from Abroad Program).
Supplementary data
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62, 6731.
1H NMR and 13C NMR spectra for all new compounds can be
found at the supplementary data associated with article. Supple-
mentary data associated with this article can be found in the online
version, at http://dx.doi.org/10.1016/j.tet.2016.02.047.
13. Shih, J.-L.; Nguyen, T. S.; May, J. A. Angew. Chem., Int. Ed. 2015, 54, 9931.
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