Piperidine-appended imidazolium ionic liquid as task-specific basic-IL for Suzuki and Heck reactions and for tandem Wittig-Suzuki, Wittig-Heck, Horner-Emmons-Suzuki, and Horner-Emmons-Heck protocols

Article abstract of DOI:10.1016/j.apcata.2017.06.015

Facile, high yielding, one-pot methods for the synthesis of a library of diversely substituted bi-aryls, diarylethenes, and aryl-enoates, via Suzuki and Heck reactions, and by sequential Wittig-Suzuki, Wittig-Heck, Horner-Emmons-Suzuki, and Horner-Emmons-Heck reactions are reported. The reactions employ piperidine-appended imidazolium ionic liquid [PAIM][NTf₂] as a task-specific basic-IL, butyl-methyl-imidazolium ionic liquid [BMIM][X] (X?=?PF₆, BF₄) as solvent, and catalytic amounts of Pd(OAc)₂ with no other additives. Wittig and Horner-Emmons reactions are effected by reacting substituted benzaldehydes with 4-bromobenzyl-PPh₃ (or bromomethyl-PPh₃) phosphonium salts, or diethylphosphonate with bromobenzaldehydes respectively, to form the corresponding ethenes. Subsequent cross-coupling reactions are accomplished by addition of aryl-boronic acid or phenyl-ethenes along with Pd(OAc)₂ to bring about the aforementioned hyphenated transformations. The feasibility to perform double-olefination via Wittig and Horner-Emmons reactions with dialdehydes to form highly conjugated bis-styryl and bis-enoate compounds is also shown. The [BMIM][X] solvent is recycled and reused.

Full text of DOI:10.1016/j.apcata.2017.06.015

Accepted Manuscript
Title: Piperidine-appended imidazolium ionic liquid as
task-specific basic-IL for Suzuki and Heck reactions and for
tandem Wittig-Suzuki, Wittig-Heck, Horner-Emmons-Suzuki,
and Horner-Emmons-Heck protocols
Authors: Hemantkumar M. Savanur, Rajesh G. Kalkhambkar,
Kenneth K. Laali
PII:
S0926-860X(17)30264-8
DOI:
Reference:
http://dx.doi.org/doi:10.1016/j.apcata.2017.06.015
APCATA 16277
To appear in:
Applied Catalysis A: General
Received date:
Revised date:
Accepted date:
20-4-2017
12-6-2017
13-6-2017
Please cite this article as: Hemantkumar M.Savanur, Rajesh G.Kalkhambkar,
Kenneth K.Laali, Piperidine-appended imidazolium ionic liquid as task-specific basic-
IL for Suzuki and Heck reactions and for tandem Wittig-Suzuki, Wittig-Heck,
Horner-Emmons-Suzuki, and Horner-Emmons-Heck protocols, Applied Catalysis A,
Generalhttp://dx.doi.org/10.1016/j.apcata.2017.06.015
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1
2nd Revision
Manuscript for Applied Catalysis A – General
Senior corresponding author: Kenneth Laali. E-mail: Kenneth.Laali@UNF.edu; Tel.: +1 904 6201503; fax: +1 902
203535. Other corresponding author: Rajesh G. Kalkhambkar: E-mail rgkalkhambkar@gmail.com; Tel.: +91
902831760; fax: +91 836 2744334
6
9
Piperidine-appended imidazolium ionic liquid as task-specific basic-IL for Suzuki
and Heck reactions and for tandem Wittig-Suzuki, Wittig-Heck, Horner-Emmons-
Suzuki, and Horner-Emmons-Heck protocols.
a
*a
b
Hemantkumar M. Savanur, Rajesh G. Kalkhambkar, , Kenneth K. Laali*
a)
Department of Chemistry, Karnatak University’s Karnatak Science College, Dharwad
Karnatak 580001, India; b) Department of Chemistry, University of North Florida, 1 UNF Drive,
Jacksonville, Florida 32224, USA
Graphical Abstract

2
Highlights



[PAIM][NTf
[PAIM][NTf
2
]/[BMIM][X]/Pd-catalyst for Suzuki and Heck cross-coupling without additive
]/[BMIM][X] for Horner-Emmons and Wittig mono- and bis-olefinations
2
The Wittig-Suzuki, Wittig-Heck, Horner-Emmons-Suzuki, and Horner-Emmons-Heck hyphenated
one-pot protocols


Synthesis of a diverse pool of biaryls, diaryl-ethenes, and aryl-enoates
Feasibility to recycle and reuse [BMIM][X]
ABSTRACT
Facile, high yielding, one-pot methods for the synthesis of a library of diversely
substituted bi-aryls, diarylethenes, and aryl-enoates, via Suzuki and Heck reactions, and by
sequential Wittig-Suzuki, Wittig-Heck, Horner-Emmons-Suzuki, and Horner-Emmons-Heck
reactions are reported. The reactions employ piperidine-appended imidazolium ionic liquid
[
PAIM][NTf
PF , BF ) as solvent, and catalytic amounts of Pd(OAc)2, with no other additives. Wittig and
Horner-Emmons reactions are effected by reacting substituted benzaldehydes with 4-
bromobenzyl-PPh (or bromomethyl-PPh ) phosphonium salts, or diethylphosphonate with
2
] as a task-specific basic-IL, butyl-methyl-imidazolium ionic liquid [BMIM][X] (X
=
6
4
3
3
bromobenzaldehydes respectively, to form the corresponding ethenes. Subsequent cross-coupling
reactions are accomplished by addition of aryl-boronic acid or phenyl-ethenes along with
Pd(OAc) to bring about the aforementioned hyphenated transformations. The feasibility to
2
perform double-olefination via Wittig and Horner-Emmons reactions with dialdehydes to form
highly conjugated bis-styryl and bis-enoate compounds is also shown. The [BMIM][X] solvent is
recycled and reused.
Keywords: [PAIM][NTf ] as basic-IL; [BMIM][X] as solvent; Suzuki and Heck; Wittig and
2
Horner-Emmons; tandem protocols; bis-olefination
2

3
1
. INTRODUCTION
The Suzuki-Miyaura and Mizoroki-Heck reactions are two of the most important C-C
bond forming protocols that have had a tremendous impact on the practice of
synthetic/preparative chemistry, not only in academia but also in industry [1-4]. Their wide
application stems from broad scope, flexibility and tolerance toward functional groups, and
availability of the coupling components.
The essential ingredients of the Suzuki coupling reaction are Pd (or Ni) catalyst, along
with a base, and ligand (depending on the substrates), and solvents such as THF, DMF and
dioxane. The Heck reaction uses a Pd catalyst, with or without phosphine ligand, along with a
base, and requires high temperature. In some cases, bases such as Et N also serve as solvent, but
3
otherwise high boiling solvents such as DMF and THF are employed [3,4].
Ionic liquids (ILs) offer numerous advantages in Pd-catalyzed cross-coupling reactions,
namely by lowering the energy of the polar transition state or intermediates in the catalytic cycle,
by increasing the reactivity of the reactants, and by virtue of their ability to solubilize the Pd
catalyst. They replace hazardous organic solvents and also offer good prospects for recycling and
reuse. Various classes of ILs and Pd catalysts have been employed in the Suzuki and Heck
reactions. Task-specific ILs (TSILs) that are base-appended, and/or ligand tethered, and
supported-ILs with immobilized-Pd catalysts, have opened up new vistas in cross-coupling
reactions. Progress in the Pd-catalyzed cross-coupling reactions in ILs is summarized in a
comprehensive recent survey [5].
In continuation of our previous studies on the utility of ILs and TSILs as solvent and
catalyst in metal-mediated transformations [6-8], and their utility in the Sonogashira coupling
[9], we report here on high yielding one-pot methods for the synthesis of a library of diversely
substituted biaryls, diarylethenes, and aryl-enoates via Suzuki and Heck reactions, and by
sequential Wittig-Suzuki, Wittig-Heck, Horner-Emmons-Suzuki, and Horner-Emmons-Heck
transformations, employing the piperidine-appended imidazolium-IL [PAIM][NTf
as a task-specific basic-IL, [BMIM][X] (X = PF , BF ) as solvent and catalytic amounts of
Pd(OAc)2, with no other additives. Wittig and Horner-Emmons reactions were effected in
2
] (Figure 1)
6
4
[PAIM][[NTf
2
]/[BMIM][X] by using phosphonium salts or phosphonates respectively.
3

4
Subsequent addition of the Pd-catalyst along with boronic acids or styrenes brings about the
indicated hyphenated transformations, leading to a host of high value small molecules. The
[BMIM][X] is used as solvent and is recycled and reused.
Figure 1. [PAIM][NTf ]
2
2
. Experimental
2
.1. General
The reagents employed were of high purity commercial samples which were used as received
Fischer, Merck and Sigma-Aldrich). Butyl methyl imidazolium ILs [BMIM][X] were
synthesized by using established literature procedures [10], similarly the basic IL [PAIM][NTf
(
2
]
was synthesized in two steps by using previously reported procedures [9,11]. Column
chromatography was performed on silica gel (200-400 mesh) and TLC was performed on silica
gel 60F254 (Fischer) TLC plates visualized under UV light (254 nm) or by iodine vapors. Melting
1
points were determined in open capillaries on a Buchi apparatus and are uncorrected. H NMR
and 13C NMR spectra were recorded using Bruker AC-300F (300 MHz) and AC-400F (400
MHz) instruments, using CDCl
3
or DMSO-d
6
as solvent with TMS as internal standard. GC
,
analyses were performed on Nucon 5700 series gas chromatograph. GC-MS analyses were
performed on a Shimadzu 2010 series mass selective detector instrument. Elemental analysis was
carried out by using Heraus CHN rapid analyzer. Boiling points were determined by Thiele tube
apparatus and are uncorrected. All compounds gave C, H and N analysis within ± 0.4% of the
theoretical values.
2
.2. General procedure for the Suzuki and Heck coupling reactions (Tables 1-2)
An oven-dried reaction tube equipped with a magnetic stirrer bar was charged with the aryl-
boronic acid (Table 1) or the substituted alkene (Table 2) (1.3 mmol), aryl (or benzyl) bromide
4

5
(1.1 mmol), Pd(OAc)
2
(5-6 mol%), [PAIM][NTf
2
] (4 mmol), and [BMIM][PF
6
] (7 mL). The
o
reaction mixture was stirred under a nitrogen atmosphere at 60-70 C, and the progress of the
reaction was monitored by TLC. After completion (2-3 h in the Suzuki reaction and 4-7 h for the
Heck reaction) the reaction mixture was extracted 3 times with hexane/ethyl acetate (80:20) and
the products were purified by flash column chromatography using hexane/ethyl acetate (80:20)
or DCM/MeOH (95:5).
1
2
-Phenylfuran (1.1):12,13 White solid. mp 160-162 ºC. H NMR (400 MHz, CDCl
3
): δ 6.21-6.33
): δ 118.9, 120.6, 125.30,
O: C, 83.31;
1
3
(
m, 2H, ArH), 7.15-7.28 (m, 6H, ArH). C NMR (100 MHz, CDCl
3
+
1
26.8, 129.1, 130.3, 134.2 and 145.6. GC-MS: m/z 144 M ; Anal. Calc. For C10
H
8
H, 5.59 %. Found: C, 83.30; H, 5.60 %.
14
1
2
-(Naphthalen-2-yl)furan (1.2): White solid. mp 77-79 ºC. H NMR (400 MHz, CDCl ): δ
3
1
3
6
.39-6.40 (m, 2H, ArH), 7.35-7.44 (m, 3H, ArH), 7.54-7.68 (m, 4H, ArH), 7.83 (s, 1H, ArH). C
NMR (100 MHz, CDCl
3
): δ 103.7, 108.5, 122.6, 123.8, 124.8, 125.7, 126.1, 126.9, 128.0, 128.7,
+
1
34.2, 135.3, 153.1 and 155.2. GC-MS: m/z 194 M . Anal. Calc. For C14
H10O: C, 86.57; H, 5.19
%. Found: C, 86.58; H, 5.20 %.
1
2
-(Furan-2-yl)pyridine (1.3): Colorless liquid bp 228-230 ºC. H NMR (400 MHz, CDCl
3
): δ
1
3
6
.49-6.61 (m, 2H, ArH), 6.95-7.06 (m, 4H, ArH), 8.16 (d, J = 7.2 Hz, 1H, ArH). C NMR (100
MHz, CDCl
3
): δ 107.8, 107.9, 121.2, 122.2, 132.5, 140.9, 146.8, 149.9 and 153.3. GC-MS: m/z
NO: C, 74.47; H, 4.86; N, 9.65 %. Found: C, 74.46; H, 4.85; N,
+
1
9
45 M .Anal. Calc. For C
9
H
7
.64 %.
1
5
o
1
Diphenylmethane (1.4): Colorless liquid. bp 260-262 C. H NMR (400 MHz, CDCl
3
): δ 3.92
1
3
(s, 2H, CH
2
), 7.31 (m, 4H, ArH), 7.40-7.58 (m, 6H, ArH), C NMR (100 MHz, CDCl
3
): δ 40.8,
+
1
9
20.5, 121.3, 122.3, 125.0, 123.6 and 142.0. GC-MS: m/z 168 M . Anal. Calc. For C13
H12: C,
2.81; H, 7.19 %. Found: C, 92.82; H, 7.20 %.
16
o
1
2
-Phenylnaphthalene (1.5): White solid. mp 104-106 C. H NMR (400 MHz, CDCl ): δ 7.28
3
(t, J = 7.8, 6.8 Hz, 1H, ArH), 7.32-7.41 (m, 4H, ArH), 7.42-7.57 (m, 4H, ArH), 7.61(d, J = 8 Hz,
1
3
1
1
H, ArH), 7.70 (d, J = 7.6 Hz, 1H, ArH), 7.89 (s, 1H, ArH). C NMR (100 MHz, CDCl ): δ
3
20.9, 121.5, 122.2, 123.0, 124.1, 124.3, 125.2, 126.3, 127.1, 128.4, 128.6, 129.5, 133.5, 137.0,
5

6
+
1
9
37.9 and 139.4. GC-MS: m/z 204 M . Anal. Calc. For C16
H12: C, 94.08; H, 5.92 %. Found: C,
4.09; H, 5.92 %.
1
6
o
1
2
-Phenylpyridine (1.6): Colorless liquid. bp 265-267 C. H NMR (400 MHz, CDCl
3
): δ 7.04-
7
.13 (m, 2H, ArH), 7.15-7.30 (m, 5H, ArH), 7.33 (d, 1H, J = 7.2 Hz, ArH), 8.05 (d, 1H, J = 7.6
Hz, ArH). 13C NMR (100 MHz, CDCl
): δ 122.2, 124.0, 125.0, 126.3, 127.1, 127.9, 129.1,
3
+
1
34.0, 138.1, 150.9 and 154.7. GC-MS: m/z 155 M . Anal. Calc. For C11
9
H N: C, 85.13; H, 5.85;
N, 9.03 %. Found: C, 85.14; H, 5.86; N, 9.05 %.
o
1
2
-Benzylfuran (1.7): Colorless liquid. bp 220-222 C. H NMR (400 MHz, CDCl
3
): δ 3.90 (s,
1
3
2
H, CH ), 6.36-6.94 (m, 2H, ArH ), 7.0-7.13 (m, 5H, ArH), 7.63(d, 1H, J = 7.2 Hz, ArH). C
2
NMR (100 MHz, CDCl
3
): δ 40.8, 119.4, 123.4, 126.5, 129.5, 130.0, 132.1, 137.4 and 143.5. GC-
10O: C, 83.51; H, 6.37 %. Found: C, 83.52; H, 6.36 %.
+
MS: m/z 159 M . Anal. Calc. For C11
H
o
1
2
-(6-Methoxynaphthlene-2-yl)furan (1.8): Colorless liquid. bp 360-362 C. H NMR (400
MHz, CDCl ): δ 3.83 (s, 3H, OCH ), 6.41 (d, J = 7.6 Hz, 1H, ArH), 6.52(t, J = 7.2, 6.8 Hz, 1H,
ArH), 7.22 (s, 1H, ArH), 7.25-7.36 (m, 5H, ArH), 7.44 (s, 1H, ArH). 13C NMR (100 MHz,
3
3
CDCl
3
): δ 57.1, 112.8, 118.0, 118.3, 120.0, 125.7, 128.5, 128.9, 129.2, 129.8, 132.8, 138.9,
+
1
47.2, 152.9, and 154.7. GC-MS: m/z 224 M . Anal. Calc. For C15
H O
12 2
: C, 80.34; H, 5.39 %.
Found: C, 80.35; H, 5.40 %.
15
o
1
2
-Methoxy-6-phenylnaphthalene (1.9): Yellow solid. mp 158-160 C. H NMR (400 MHz,
CDCl
ArH), 7.59-7.69 (m, 3H, ArH), 7.81(s, 1H, ArH). C NMR (100 MHz, CDCl
16.1, 121.2, 121.4, 123.9, 124.1, 125.8, 127.0, 128.5, 130.0, 131.1, 132.5, 133.0, 136.5, 138.1
3
): δ 3.92 (s, 3H, OCH
3
), 6.30 (s, 1H, ArH), 7.06 (d, J = 8 Hz, 1H, ArH), 7.41-7.55 (m, 5H,
1
3
3
): δ 55.2, 102.4,
1
+
and 155.9. GC-MS: m/z 236 M . Anal. Calc. For C17
7.16; H, 6.04 %.
H14O: C, 87.15; H, 6.02 %. Found: C,
8
Biphenyl (1.10):15-17 White solid. mp 64-66 C. H NMR (400 MHz, CDCl
): δ 7.33 (t, 2H, J =
o
1
3
1
3
7
.6 Hz, ArH), 7.40 (t, J = 7.6 Hz, 4H, ArH), 7.61 (d, 4H, J = 7.8 Hz, ArH). C NMR (100 MHz,
+
CDCl ): δ 123.9, 124.8, 127.1, 128.4, 129.0, and 134.8. GC-MS: m/z 154 M . Anal. Calc. For
3
C
12
H10: C, 93.46; H, 6.54 %. Found: C, 93.47; H, 6.55 %.
-Methylbiphenyl (1.11):17,18 White solid. mp 48-50 C. H NMR (400 MHz, CDCl
o
1
): δ 2.07 (s,
4
3
3
H, CH ), 7.22 (d, J= 7.6 Hz, 2H, ArH), 7.31 (d, J = 7.8 Hz, 2H, ArH), 7.25 (d, J= 7.6 Hz,
3
6

7
1
3
2
1
H,ArH), 7.70-7.77 (m, 3H, ArH). C NMR (100 MHz, CDCl
3
): δ 22.9, 121.3, 122.5, 123.2,
+
24.2, 124.9, 126.3, 127.0, 128.2, 129.9 and 133.1. GC-MS: m/z 168 M . Anal. Calc. For
C
13
H12: C, 92.81; H, 7.19 %. Found: C, 92.82; H, 7.20 %.
-Methoxybiphenyl (1.12):15,17 White solid. mp 90-92 C. H NMR (400 MHz, CDCl
o
1
): δ 3.91
4
3
(
s, 3H, OCH ), 7.12 (d, J = 7.6 Hz, 2H, ArH), 7.42 (d, J = 7.8 Hz, 2H, ArH), 7.45-7.52 (m,
3
1
3
5
1
H,ArH). C NMR (100 MHz, CDCl
3
): δ 59.8, 119.5, 122.4, 124.0, 126.4, 127.0, 128.1, 129.5,
+
30.5, 134.5 and 156.1. GC-MS: m/z 184 M .Anal. Calc. For C13
H12O: C, 84.75; H, 6.57 %.
Found: C, 84.76; H, 6.58 %.
19
o
1
2
-(4-Methoxyphenyl)furan (1.13): White solid. mp 49-52 C. H NMR (400 MHz, CDCl
3
-d ):
6
δ 3.85 (s, 3H, OCH ), 6.36-6.43 (m, 2H, ArH), 6.93 (d, J = 7.6, 2H, ArH), 7.29-7.40 (m, 3H,
3
1
3
ArH). C NMR (100 MHz, CDCl ): δ 57.9, 104.2, 107.2, 115.9, 125.7, 130.2, 140.1, 152.2 and
3
+
1
5
63.3. GC-MS: m/z 174 M . Anal. Calc. For C11
H
10
O
2
: C, 75.84; H, 5.79 %. Found: C, 75.85; H,
.80 %.
20
1
(
E)-2-Styrylthiophene (2.1): Yellow solid. mp 111-113 ºC. H NMR (400 MHz, CDCl
3
): δ
6
3
1
.73 (d, J = 16.3 Hz, 1H, trans-olefinic H), 6.97 (d, J = 16 Hz, 1H, trans-olefinic H), 7.01-7.1 (m,
1
3
H, ArH), 7.31-7.40 (m, 5H, ArH). C NMR (100 MHz, CDCl
3
): δ 121.0, 121.3, 123.3, 124.1,
+
25.8, 127.9, 129.5, 133.3, 136.2, 138.2, 139.0 and 140.3. GC-MS: m/z 186 M . Anal. Calc. For
12
C H10S: C, 77.37; H, 5.41 %. Found: C, 77.38; H, 5.40 %.
o
1
(
E)-2-(2-(Naphthalen-2-yl)vinyl)thiophene (2.2): Yellow solid. mp 208-210 C. H NMR (400
MHz, CDCl ): δ 6.78 (d, J = 16.5 Hz, 1H, trans-olefinic H), 6.91 (d, J = 16.6 Hz, 1H, trans-
olefinic H), 7.09-7.18 (m, 3H, ArH), 7.30-7.42 (m, 3H, ArH), 7.43-7.45 (m, 4H, ArH). C NMR
3
1
3
(100 MHz, CDCl
3
): δ = 111.8, 119.3, 120.5, 121.7, 123.0, 124.3, 125.1, 126.3, 127.4, 128.3,
+
1
8
32.5, 133.0, 134.5, 135.2, 136.8 and 138.0. GC-MS: m/z 236 M . Anal. Calc. For C16
H12S: C,
1.31; H, 5.12 %. Found: C, 81.32; H, 5.13 %.
21
o
1
(
E)-2-(2-(Thiophen-2-yl)vinyl)pyridine (2.3): White solid. mp 82-84 C. H NMR (400 MHz,
CDCl ): δ = 6.85-6.91 (m, 2H, ArH), 7.18 (d, J = 16 Hz, 1H, trans-olefinic H) 7.30-7.45 (m, 4H,
ArH), 7.55 (d, J = 16.6 Hz, 1H, trans-olefinic H), 8.01 (d, J = 7.6 Hz, 1H, ArH). C NMR (100
3
1
3
MHz, CDCl
3
): δ 124.1, 125.3, 127.2, 129.3, 133.2, 133.9, 135.0, 136.4, 138.2, 145.1 and 146.9.
7

8
+
GC-MS: 187 m/z M . Anal. Calc. For C11
H
9
NS: C, 70.55; H, 4.84; N, 7.48 %. Found: C, 70.56;
H, 4.85; N, 7.49 %.
E)-2-Styrylpyridine (2.4):20,22 White solid. mp 150-152 ºC. H NMR (400 MHz, CDCl
1
): δ
(
3
7
7
1
.06-7.15 (m, 2H, ArH), 7.21 (d, J = 16.2 Hz, 1H, trans-olefinic H), 7.31-7.42 (m, 6H, ArH),
1
3
.49 (d, J = 16 Hz, 1H, trans-olefinic H), 8.01 (d, 1H, ArH). C NMR (100 MHz, CDCl ): δ
3
21.5, 123.3, 124.0, 126.3, 127.1, 127.8, 128.2, 130.0, 131.2, 133.9, 138.5, 149.1 and 153.5. GC-
+
MS: 181 m/z M . Anal. Calc. For C13
H11N: C, 86.15; H, 6.12; N, 7.73 %. Found: C, 86.16; H,
6
.11; N, 7.75 %.
1
(
E)-2-(2-(6-Methoxynaphthalen-2-yl)vinyl)thiophene(2.5): Yellow solid. mp 198-200 ºC. H
NMR (400 MHz, CDCl
3
): δ 3.55 (s, 3H, OCH
3
), 6.81 (s,1H, ArH), 6.89 (d, J = 16.3 Hz, trans-
olefinic H), 6.99 (d, J = 16.5 Hz, trans-olefinic H), 7.10-7.11 (m, 3H, ArH), 7.41 (d, J = 7.8 Hz,
1
3
1
H, ArH), 7.51-7.58 (m, 3H, ArH), 7.73 (d, J = 7.2 Hz, 1H, ArH). C NMR (100 MHz, CDCl ):
3
δ 56.4, 119.4, 121.0, 122.5, 123.0, 125.1, 126.9, 128.1, 129.0, 130.9, 131.1, 132.0, 134.5, 135.3,
+
1
36.4, 138.2 and 151.9. GC-MS: m/z 266 M . Anal. Calc. For C17
H14OS: C, 76.66; H, 5.30 %.
Found: C, 76.67; H, 5.32 %.
23
1
(
E)-2-Methoxy-6-styryl-naphthalene (2.6): White solid. mp 175-177 ºC. H NMR (400 MHz,
CDCl
d, J = 16 Hz, trans-olefinic H), 7.12-7.23 (m, 5H, ArH), 7.42-7.53 (m, 4H, ArH) 7.82 (s, 1H,
ArH). 13C NMR (100 MHz, CDCl
): δ 56.5, 107.8, 111.2, 119.7, 121.0, 121.5, 123.1, 123.4,
23.8, 125.1, 125.7, 126.0, 127.1, 128.5, 130.0, 132.0, 136.3, 139.1 and 154.5. GC-MS: m/z 260
3
): δ 3.82 (s, 3H, OCH
3
), 6.85 (d, J = 16 Hz, 1H, trans-olefinic H), 7.02 (s, 1H, ArH), 7.10
(
3
1
+
M . Anal. Calc. For C19
H16O: C, 87.66; H, 6.19 %. Found: C, 87.67; H, 6.18 %.
E)-2-Styryl-naphthalene (2.7):16,24,25 White crystalline solid. mp 70–71 C. H NMR (400
o
1
(
MHz, CDCl
3
): δ 6.96 (d, J = 16 Hz, 1H, trans-olefinic H), 7.07 (d, J = 16 Hz, 1H, trans-olefinic
1
3
H), 7.31-7.40 (m, 5H, ArH), 7.45-7.55 (m, 6H, ArH), 7.77 (s, 1H,ArH), C NMR (100 MHz,
CDCl
3
): δ 120.0, 121.1, 121.9, 122.1, 122.7, 124.8, 125.3, 126.3, 127.0, 128.1, 128.6, 129.1,
+
1
9
30.8, 131.0, 132.1, 135.9, 136.9 and 139.4. GC-MS: m/z 230 M . Anal. Calc. For C18
H14: C,
3.87; H, 6.13 %. Found: C, 93.88; H, 6.15 %.
E)-1,2-Diphenylethene (2.8):6b,16,8,24,26,27 White crystalline solid. mp 122–124 C. H NMR
o
1
(
1
3
(
400 MHz, CDCl
3
): δ 7.01 (s, 2H), 7.12-7.27 (m, 6H, ArH), 7.50 (m, 4H, ArH). C NMR (100
8

9
+
MHz, CDCl
3
): δ 127.0, 127.9, 128.3, 129.3 and 134.4. GC-MS: m/z 180 M . Anal. Calc. For
14
C H12: C, 93.29; H, 6.71 %. Found: C, 93.31; H, 6.72 %.
E)-1-Methyl-4-styryl-benzene (2.9):6b,16,26,28 White crystalline solid. mp 119–122 C. H NMR
400 MHz, CDCl ): δ 2.49 (s, 3H, CH ), 6.98 (d, J = 16.4 Hz, 1H, trans-olefinic H), 7.10 (d, J =
6.5 Hz, 1H, trans-olefinic H), 7.16-7.27 (m, 5H, ArH), 7.30 (d, J = 7.8 Hz, 2H, ArH), 7.39 (d, J
o
1
(
(
3
3
1
=
7.6 Hz, 2H, ArH). 13C NMR (100 MHz, CDCl
3
): δ 28.2, 121.5, 122.8, 123.9 124.2, 125.5,
+
1
26.3, 127.7, 128.2, 129.3, 134.9, 137.2 and 138.6. GC-MS: m/z 194 M . Anal. Calc. For
15
C H14: C, 92.74; H, 7.26 %. Found: C, 92.73; H, 7.27 %.
E)-Ethyl 3-(4-chlorophenyl)-3-phenyl-acrylate (2.10):6b,29 Brown liquid. H NMR (400 MHz,
CDCl ): δ 1.58 (t, 3H), 4.80-4.92 (q, 2H), 6.55 (s, 1H), 7.19-7.29 (m, 5H, ArH), 7.45 (d, J = 8
Hz, 2H, ArH), 7.53 (d, J = 8.6 Hz, 2H, ArH). C NMR (100 MHz, CDCl
26.0, 127.5, 128.6, 129.0, 129.8, 133.2, 137.0, 138.4, 152.8 and 168.7. GC-MS: m/z 286 M+.
Anal. Calc. For C17 : C, 71.20; H, 5.27 %. Found: C, 71.21; H, 5.25 %.
1
(
3
1
3
3
): δ 15.0, 53.1, 117.9,
1
H15ClO
2
(
E)-Methyl 3-(4-methoxyphenyl)-2-methyl-acrylate (2.11):6b,28 Colorless liquid. bp 290-292
o
1
C. H NMR (400 MHz, CDCl ): δ 2.11 (s, 3H), 3.65 (s, 3H), 3.91 (s, 3H), 7.08 (d, J = 8 Hz, 2H,
3
1
3
ArH), 7.15 (d, J = 7.6 Hz, 2H, ArH), 7.35 (s, 1H). C NMR (100 MHz, CDCl
3
): δ 15.0, 53.3,
+
5
4.8, 117.9, 127.92, 128.5, 130.9, 138.2, 155.5 and 163.1. GC-MS: m/z 206 M . Anal. Calc. For
C
12
H
14
3
O : C, 69.88; H, 6.84 %. Found: C, 69.89; H, 6.85 %.
E)-Ethyl 3-(4-methoxyphenyl)-3-phenyl-acrylate (2.12):6b,29 Colorless liquid. bp 380-382 C.
o
(
1H NMR (400 MHz, CDCl
): δ 1.82 (t, J = 7.2 Hz, 3H), 3.40 (s, 3H), 4.05 (q, 2H), 6.45 (s, 1H),
3
1
3
6
.77 (d, J = 8 Hz, 2H, ArH), 7.18-7.21 (m, 5H, ArH), 7.40 (d, J = 7.6 Hz, 2H, ArH). C NMR
(100 MHz, CDCl
3
): δ 15.1, 56.9, 59.0, 119.1, 120.1, 127.0, 128.0, 129.8, 130.9, 136.7, 139.5,
+
1
40.9, 153.9 and 164.5. GC-MS: m/z 282 M . Anal. Calc. For C18
H
18
O : C, 76.57; H, 6.43 %.
3
Found: C, 76.58; H, 6.42 %.
o
1
(
(
(
E)-Methyl 2-methyl-3-p-tolyl-acrylate (2.13):6b,24 Colorless liquid. bp 260-262 C. H NMR
400MHz, CDCl ): δ 1.85 (s, 3H), 2.11 (s, 3H), 3.80 (s, 3H), 7.29 (d, J = 7.6 Hz, 2H, ArH), 7.40
3
1
3
d, J = 8 Hz, 2H, ArH), 7.45 (s, 1H). C NMR (100 MHz, CDCl ): δ 16.3, 55.3, 65.4, 122.9,
3
+
1
7
24.2, 128.9, 131.1, 134.2, 138.7 and 160.7. GC-MS: m/z 190 M . Anal. Calc. For C12
14
H O2: C,
5.76; H, 7.42 %. Found: C, 75.75; H, 7.40 %.
9

1
0
E)-Methyl 2-methyl-3-phenylacrylate (2.14):6b Colorless liquid. bp 250-252 C. H NMR
o
1
(
(
400MHz, CDCl ): δ 1.69 (s, 3H), 3.80 (s, 3H), 7.10-7.20 (m, 3H, ArH), 7.35 (d, J = 8 Hz, 2H,
3
1
3
ArH), 7.60 (s, 1H). C NMR (100 MHz, CDCl
3
): δ 14.5, 55.8, 122.8, 124.1, 125.2, 125.8, 127.9,
+
1
6
30.1, 135.2, 138.2 and 161.1. GC-MS: m/z 176 M . Anal. Calc. For C11
H
12
2
O : C, 74.98; H,
.86 %. Found: C, 74.96; H, 6.87 %.
2
.3. General procedure for the Wittig-Suzuki (Tables 3a-3b) and Wittig-Heck (Table 4) tandem
reactions
2
.3.1. Wittig-Suzuki: An oven-dried reaction tube equipped with a magnetic stirrer bar was
charged with the selected aldehyde (1.3 mmol), 4-bromobenzyl-PPh bromide or bromomethyl-
PPh bromide salts (1.1 mmol), [PAIM][NTf ] (4 mmol), and [BMIM][X] (5-6 mL). The
reaction mixture was stirred and heated at 60-65 °C under a nitrogen atmosphere for 30 minutes.
Then the aryl boronic acid (1.3 mmol) was introduced along with Pd(OAc) (10 mol%) and
3
3
2
2
heating was resumed for an additional 5-8 hours while monitoring by TLC. Upon completion,
the reaction mixture was extracted 4 times with hexane/ethyl acetate (80:20), dried over
anhydrous magnesium sulfate, the solvent was removed under vacuum, and the crude products
were purified by flash chromatography hexane/ethyl acetate (80:20) or DCM/MeOH (95:5).
2
.3.2. Wittig-Heck: The same procedure as in 2.3.1 was followed except that methyl-Ph P
3
iodide salt was used for the Wittig reaction with selected aldehydes and PhI was used instead of
boronic acids.
-Styryl-1,1'-biphenyl (3a.1):27,30 White solid. mp 215-217 C. H NMR (400 MHz, CDCl
): δ
o
1
4
6
7
3
.97 (d, J = 16 Hz, 1H, trans-olefinic H), 7.13 (d, J = 16 Hz, 1H, trans-olefinic H), 7.33 (d, J =
.6 Hz 2H, ArH), 7.35-7.41 (m, 6H, ArH), 7.45-7.52 (m, 6H, ArH). 13C NMR (100 MHz,
CDCl
3
): δ 125.5, 126.0, 126.2, 127.0, 127.5, 127.8, 128.3, 128.9, 129.1, 130.3, 130.7, 131.1,
+
1
9
31.8 and 132.4. GC-MS: m/z 270 M . Anal. Calc. For C20
H16: C, 93.71; H, 6.29 %. Found: C,
3.72; H, 6.28 %.
30
o
1
4
-(4-Methylstyryl)-1, 1’-biphenyl (3a.2): White solid, mp 224-226 C; H NMR (400 MHz,
): δ 2.15 (s, 3H, CH ), 7.03 (d, J = 16 Hz, 1H, trans-olefinic H), 7.10 (d, J = 16 Hz, 1H,
CDCl
3
3
1
0

1
1
trans-olefinic H), 7.14-7.23 (m, 5H, ArH), 7.42 (d, J = 7.8 Hz, 2H, ArH), 7.53-7.65 (m, 6H,
ArH). 13C NMR (100 MHz, CDCl
): δ 25.8, 122.0, 123.4, 125.2, 126.4, 127.0, 128.7, 129.5,
3
+
1
30.4, 132.4, 133.2, 134.9, 135.5, 136.1, 137.0, 137.6 and 138.4. GC-MS: m/z 270 M . Anal.
Calc. For C21H18: C, 93.29; H, 6.71 %. Found: C, 93.28; H, 6.72 %.
3
0
o
1
4
-(4-Methoxystyryl)-1, 1’-biphenyl (3a.3): White solid, mp 199-201 C; H NMR (400 MHz,
CDCl ): δ 3.68 (s, 3H, OCH ), 6.91 (d, J = 16 Hz, 1H, trans-olefinic H ), 7.06 (d, J = 16 Hz, 1H,
trans-olefinic H), 7.37 (d, J = 7.6 Hz, 2H, ArH), 7.42 (d, J = 7.6 Hz, 2H, ArH), 7.55-7.62 (m, 3H,
3
3
1
3
ArH), 7.73-7.83 (m, 6H, ArH). C NMR (100 MHz, CDCl
3
): δ 59.5, 121.4, 122.7, 123.9, 124.5,
1
25.0, 126.7, 127.0, 127.6, 128.7, 129.9, 130.5, 131.6, 132.4, 134.2, 134.9 and 155.6. GC-MS:
+
m/z 286 M . Anal. Calc. For C21H18O: C, 88.08; H, 6.34 %. Found: C, 88.09; H, 6.35 %.
3
0
o
1
4
-(4-Chlorostyryl)-1, 1’-biphenyl (3a.4): White solid. mp 245-247 C; H NMR (400 MHz,
CDCl ): δ 6.90 (d, J = 16 Hz, 1H, trans-olefinic H), 7.01 (d, J = 16 Hz, 1H, trans-olefinic H),
3
1
3
7
.31 (d, J = 8 Hz, 2H, ArH), 7.38-7.46 (m, 5H, ArH), 7.49-7.67 (m, 6H, ArH). C NMR (100
MHz, CDCl
3
): δ 123.1, 123.5, 125.3, 125.9, 126.4, 127.3, 128.0, 128.3, 130.0, 130.5, 131.6,
+
1
32.1, 132.9, 135.2, 135.8 and 154.2. GC-MS: m/z 290 M . Anal. Calc. For C20
H15Cl: C, 82.61;
H, 5.20 %. Found: C, 82.63; H, 5.21 %.
o
1
4
-(2-Methylstyryl)-1,1'-biphenyl(3a.5): White solid. mp 201-203 C. H NMR (400 MHz,
CDCl ): δ 2.01 (s, 3H. CH ), 6.91 (d, J = 16 Hz, 1H, trans-olefinic H), 7.03 (d, J = 16 Hz, 1H,
trans-olefinic H), 7.12-7.21 (m, 2H, ArH), 7.32 (d, J = 7.6 Hz, 1H, ArH), 7.35-7.41 (m, 4H,
3
3
1
3
ArH), 7.49-7.58 (m, 6H, ArH). C NMR (100 MHz, CDCl
3
): δ 20.4, 122.9, 123.8, 124.1, 125.4,
1
1
6
26.0, 127.2, 128.1, 128.9, 129.5, 130.5, 131.3, 132.0, 133.1, 133.6, 135.6, 136.2, 136.5 and
+
37.3. GC-MS: m/z 270 M . Anal. Calc. For C21
H18: C, 93.29; H, 6.71 %. Found: C, 93.27; H,
.72 %.
33
o
1
(
E)-2-(2-(Naphthalen-2-yl)vinyl)furan (3b.1): Colorless liquid. bp 280-282 C. H NMR (400
MHz, CDCl ): δ 6.62-6.70 (m, 2H, ArH), 6.83 (d, J = 16.6 Hz, 1H, trans-olefinic H), 7.10 (d, J =
6.2 Hz, 1H, trans-olefinic H), 7.45-7.56 (m, 4H, ArH), 7.77-7.82 (m, 4H, ArH). C NMR (100
3
1
3
1
MHz, CDCl
3
): δ 110.0, 112.5, 119.6, 120.0, 122.1, 122.9, 124.3, 128.7, 129.1, 129.5, 131.5,
+
1
34.1, 137.9, 139.2, 147.9 and 152.5. GC-MS: m/z 220 M . Anal. Calc. For C16
H12O: C, 87.25;
H, 5.49 %. Found: C, 87.24; H, 5.48 %.
1
1

1
2
o
1
(
E)-2-(2-(Furan-2-yl)vinyl)pyridine (3b.2): Colorless liquid. bp 260-262 C. H NMR (400
MHz, CDCl ): δ 6.33-6.41 (m, 2H, ArH), 7.05 (d, J = 16.2 Hz, 1H, trans-olefinic H), 7.28 (d, J =
6.6 Hz, 1H, trans-olefinic H), 7.52-7.68 (m, 4H, ArH), 8.09 (d, J = 7.2 Hz, 1H, ArH). C NMR
3
1
3
1
(100 MHz, CDCl
3
): δ 114.7, 116.9, 124.6, 128.2, 129.8, 136.8, 138.1, 142.3, 150.0, 152.9 and
+
1
7
54.1. GC-MS: m/z 171 M . Anal. Calc. For C11
9
H NO: C, 77.17; H, 5.30; N, 8.18 %. Found: C,
7.18; H, 5.32; N, 8.19 %.
2
5
o
1
(
E)-2-styryl-furan (3b.3): White solid; mp 50-52 C. H NMR (400 MHz, CDCl
3
): δ 6.55-6.73
(m, 2H, ArH), 6.87 (d, J = 16.2 Hz, 1H, trans-olefinic H), 6.99 (d, J = 16 Hz, 1H, trans-olefinic
1
3
H), 7.33 (t, J = 7.4, 6.8 Hz, 1H, ArH), 7.41-7.50 (m, 2H, ArH), 7.51-7.62 (m, 3H, ArH). C
NMR (100 MHz, CDCl
3
): δ 118.2, 121.2, 122.0, 124.3, 125.1, 128.9, 130.5, 131.2, 134.0, 134.5,
+
1
8
49.5 and 152.9. GC-MS: m/z 170 M . Anal. Calc. For C12
H10O: C, 84.68; H, 5.92 %. Found: C,
4.67; H, 5.93 %.
o
1
(
E)-2-(4-methylphenyl)vinyl)furan (3b.5): Colorless liquid; bp 268-270 C. H NMR (400
MHz, CDCl ): δ 2.55 (s, 3H, CH ), 7.71-7.83 (m, 4H, ArH), 7.02 (d, J = 16.4 Hz, 1H, trans-
olefinic H), 7.18 (d, J = 16.5 Hz, 1H, trans-olefinic H), 7.51(d, J = 7.6 Hz, 2H, ArH), 7.58 (d, J =
3
3
1
3
7
1
.6 Hz, 1H, ArH). C NMR (100 MHz, CDCl
3
): δ = 29.9, 117.4, 117.9, 123.1, 123.8, 126.1,
+
34.4, 135.0, 139.2, 147.9 and 153.2. GC-MS: m/z 184 M . Anal. Calc. For C13
H12O: C, 84.75;
H, 6.57 %. Found: C, 84.77; H, 6.58 %.
E)-2-(2-(Thiophen-2-yl)vinyl)furan(3b.7): White solid. mp 80-82 C; 1H NMR (400 MHz,
CDCl ): δ 6.31-6.39 (m, 2H, ArH), 6.85 (d, J = 16 Hz, 1H, trans-olefinic H), 6.98 (d, J = 16.6
Hz, 1H, trans-olefinic H), 7.00-7.09 (m, 2H, ArH), 7.30 (d, J = 7.6 Hz, 1H, ArH), 7.45 (d, J = 7.2
o
(
3
1
3
Hz, 1H, ArH). C NMR (100 MHz, CDCl
3
): δ 114.7, 119.2, 122.8, 127.2, 127.8, 131.9, 134.1,
+
1
38.1, 143.0 and 152.2. GC-MS: m/z 176 M . Anal. Calc. For C10
8
H OS: C, 68.15; H, 4.58 %.
Found: C, 68.14; H, 4.57 %.
E)-1-4-(4-chlorostyryl)benzene (4.4):6b,24,26 Colorless solid. mp 125-126 C. H NMR (400
MHz, CDCl ): δ 6.81 (d, J = 16.2 Hz, 1H, trans-olefinic H), 7.02 (d, J = 16.4 Hz, 1H, trans-
olefinic H), 7.28-7.36 (m, 5H, ArH), 7.65 (d, J = 7.6 Hz, 2H, ArH), 7.82 (d, J = 7.6 Hz, 2H,
o
1
(
3
1
3
ArH). C NMR (100 MHz, CDCl
3
): δ 124.0, 125.2, 127.1, 127.4, 128.4, 129.2, 129.4, 130.7,
+
1
31.4, 132.8, 134.4 and 152.4. GC-MS: m/z 270 M . Anal. Calc. For C14
H11Cl: C, 78.32; H, 5.16
%. Found: C, 78.33; H, 5.14 %.
1
2

1
3
E)-1-methyl-2-styryl-benzene (4.5):16,26 Colorless oil. bp 285-287 C. H NMR (400 MHz,
CDCl ): δ 2.58 (s, 3H, CH ), 6.95 (d, J = 16.2 Hz, 1H, trans-olefinic H), 6.98 (d, J = 16.2 Hz,
H, trans-olefinic H), 7.04-7.12 (m, 4H, ArH), 7.17 (m, 5H, ArH). C NMR (100 MHz, CDCl
o
1
(
3
3
1
3
1
3
):
δ 20.7, 121.5, 121.7, 122.8, 123.1, 123.8, 124.5, 125.1, 125.4, 127.6, 127.9, 129.1, 130.8, 131.5
+
and 134.1. GC-MS: m/z 194 M . Anal. Calc. For C15
H, 7.25 %.
H14: C, 92.74; H, 7.26 %. Found: C, 92.72;
2
.4. General procedure for the Horner-Emmons-Suzuki and Horner-Emmons-Heck reactions
(Tables 5-6)
2
.4.1. Horner-Emmons-Suzuki: An oven-dried reaction tube equipped with a magnetic stirrer bar
was charged with mixture of 4-bromobenzaldehyde (1.3 mmol), ethyl 2-
diethylphosphoryl)acetate (1.1 mmol), [PAIM][NTf ] (4 mmol) and [BMIM][PF ] (7 mL). The
a
(
2
6
reaction mixture was stirred and heated at 60-70 °C under a nitrogen atmosphere for 4-5 hours.
Upon completion of the Horner-Emmons transformation (TLC monitoring), aryl boronic acid
(
1.5 mmol) was introduced along with Pd(OAc) (10 mol%) and heating was resumed. Upon
2
completion (TLC monitoring), the crude reaction mixture was extracted in dry ether (3-times),
dried over anhydrous magnesium sulfate, and the solvent was removed under vacuum to furnish
the crude product which was purified by flash column chromatography using hexane/ethyl
acetate (70:30) or DCM/MeOH (90:10).
2
.4.2. Horner-Emmons-Heck: A similar procedure as in 2.4.1 was followed. Upon completion of
the Horner-Emmons reaction TLC analysis), the selected aryl-ethene was introduced (1.2 mmol)
and heating was resumed. The progress of the reaction was monitored by TLC and after
completion, the crude product was twice extracted in dry ether, dried (magnesium sulfate), and
the solvent was removed to furnish the crude product which was purified by flash column
chromatography using hexane/ethyl acetate (70:30) or DCM/MeOH (90:10).
o
1
Ethyl (2E)-3-(biphenyl-4-yl)prop-2-enoate (5.1): White solid. mp. 92-94 C. H NMR (400
MHz, DMSO-d6): δ 1.49 (s, 3H, CH ), 4.33(q, 2H, CH ), 7.11 (d, J = 16.2 Hz, 1H, trans-olefinic
H), 7.33-7.42 (m, 3H, Ar-H), 7.43-7.51 (m, 2H, ArH), 7.53-7.64 (m, 4H, ArH), 7.68 (d, J = 16.4
3
2
1
3
Hz, 1H, trans-olefinic H). C NMR (100 MHz, DMSO-d6): δ 15.7, 68.1, 119.5, 126.8, 127.9,
1
3

1
4
1
28.8, 129.0, 129.5, 131.1, 131.8, 139.0 and 166.4. Anal. Calc. For C17
. Found: C, 80.94; H, 6.41 %.
H
16
2
O : C, 80.93; H, 6.39
%
o
1
Ethyl (2E)-3-(biphenyl-3-yl)prop-2-enoate (5.2): Pale yellow solid. mp. 64-66 C. H NMR
400 MHz, DMSO-d6): δ 1.56 (t, 3H, CH ), 4.12 (q, 2H, CH ), 7.01 (d, J = 16.0 Hz, 1H, trans-
olefinic H), 7.26 (s, 1H, ArH), 7.28-7.35 (m, 5H, ArH), 7.39-7.50 (m, 3H, ArH), 7.54 (d, J =
(
3
2
1
1
6.4 Hz, 1H, trans-olefinic H). 13C NMR (100 MHz, DMSO-d6): δ 15.9, 60.9, 121.4, 125.5,
26.0, 127.0, 127.5, 128.5, 129.0, 129.5, 130.1, 131.3, 132.9, 139.8, and 167.4 Anal. Calc. For
C
17
H
16
2
O : C, 80.93; H, 6.39 %. Found: C, 80.91; H, 6.40 %.
o
Ethyl (2E)-3-(3'-methylbiphenyl-3-yl)prop-2-enoate (5.3): Light brown solid. mp. 96-98 C.
1H NMR (400 MHz, DMSO-d6): δ 1.48 (t, 3H, CH
), 2.37 (s, 3H, CH ), 4.25 (q, 2H, CH ), 6.82
d, J = 16.2 Hz, 1H, trans-olefinic H), 7.20 (s, 1H, ArH), 7.33 (s, 1H, ArH), 7.49-7.58 (m, 6H,
3
3
2
(
1
3
ArH), 7.75 (d, J = 16.0 Hz, 1H, trans-olefinic H). C NMR (100 MHz, DMSO-d6): δ 16.8, 20.9,
6
1
5.0, 118.1, 125.1, 125.4, 126.4, 126.8, 128.7, 128.7, 129.0, 132.0, 132.5, 134.2, 136.9, 138.7,
49.3 and 166.0. Anal. Calc. For C18 : C, 81.17; H, 6.81 %. Found: C, 81.16; H, 6.80 %.
H
18
O
2
o
Ethyl (2E)-3-(3'-methylbiphenyl-4-yl)prop-2-enoate (5.4): Yellow solid. mp. 109-111 C.
1H NMR (400 MHz, DMSO-d6): δ 1.48 (t, 3H, CH
), 2.32 (s, 3H, Me), 4.24 (q, 2H, CH ), 7.01
d, J = 16.4 Hz, 1H, trans-olefinic H), 7.21-7.33 (m, 3H, ArH), 7.34 (s, 1H, ArH), 7.37-7.50 (m,
3
2
(
1
3
4
2
1
H, ArH), 7.68 (d, J = 16.2 Hz, 1H, trans-olefinic H). C NMR (100 MHz, DMSO-d6): δ 13.9,
1.2, 65.2, 117.8, 126.5, 127.3, 128.4, 129.5, 129.8, 132.8, 134.1, 134.7, 136.3, 138.1, 147.5 and
66.7. Anal. Calc. For C18
H
18
O : C, 81.17; H, 6.81 %. Found: C, 81.15; H, 6.82 %.
2
34
Ethyl (2E)-3-{4-[(E)-2-phenylethenyl]phenyl}prop-2-enoate(6.1): White solid. mp 137-139
o
1
C. H NMR (400 MHz, DMSO-d6): δ 1.63 (t, 3H, CH
Hz, 1H, trans-olefinic H), 7.11 (d, J = 16.2 Hz, 1H, trans-olefinic H), 7.13-7.24 (m, 3H, ArH),
.32 (d, J = 8.4 Hz, 2H, ArH), 7.5 (d, J = 8.0 Hz, 2H, ArH), 7.65 (d, J = 8.6 Hz, 2H, ArH), 7.75
3
), 4.33 (q, 2H, CH
2
), 6.84 (d, J = 16.0
7
1
3
(
d, J = 16.4 Hz, 1H, trans-olefinic H), 7.81 (d, J = 16.4 Hz, 1H, trans-olefinic H). C NMR (100
MHz, DMSO-d6): δ 17.6, 63.5, 116.3, 125.3, 125.8, 126.2, 127.3, 127.5, 128.4, 128.7, 129.1,
1
4

1
5
1
29.8, 131.3, 132.5, 133.0, 144.0 and 165.1. Anal. Calc. For C19
H
18
2
O : C, 81.99; H, 6.52 %.
Found: C, 81.97; H, 6.53 %.
Ethyl (2E)-3-{3-[(E)-2-phenylethenyl]phenyl}prop-2-enoate (6.2):31 Brown solid. mp. 129-
o
1
1
1
7
31 C. H NMR (400 MHz, DMSO-d6): δ 1.52 (t, 3H, CH
3
), 4.31 (q, 2H, CH ), 6.79 (d, J =
2
6.8 Hz, 1H, trans-olefinic H), 7.08 (d, J = 16.2 Hz, 1H, olefinic H), 7.15-7.25 (m, 5H, ArH),
.37 (s, 1H, ArH), 7.59 (d, J = 7.8 Hz, 2H, ArH), 7.61 (d, J = 8.0 Hz, 1H, ArH), 7.81 (d, J = 16.0
Hz, 1H, trans-olefinic H), 7.87 (d, J = 16.4 Hz, 1H, trans-olefinic H). 13C NMR (100 MHz,
DMSO-d6): δ 18.1, 65.4, 112.6, 124.3 124.8, 125.3, 125.7, 1264, 127.0, 127.5, 128.0, 128.7,
1
29.1, 129.5, 135.4, 137.0, 138.8, 143.8 and 163.0. Anal. Calc. For C19
. Found: C, 82.00; H, 6.50 %.
H
18
2
O : C, 81.99; H, 6.52
%
Ethyl (2E)-3-{3-[(E)-2-(4-methylphenyl)ethenyl]phenyl}prop-2-enoate (6.3): Brown solid.
o
1
mp. 138-140 C. H NMR (400 MHz, DMSO-d6): δ 1.55 (t, 3H, CH
3
), 2.25 (s, 3H, Me), 4.20 (q,
2
7
=
H, CH
2
), 6.77 (d, J = 16.4 Hz, 1H, trans-olefinic H), 6.79 (d, J = 16.8 Hz, 1H, trans-olefinic H),
.15-7.25 (m, 7H, ArH), 7.35 (s, 1H, ArH), 7.50 (d, J = 16.2 Hz, 1H, trans-olefinic H), 7.67 (d, J
13
16.02 Hz, 1H, trans-olefinic H). C NMR (100 MHz, DMSO-d6): δ 19.3, 27.4, 117.1, 126.0,
26.1, 126.9, 127.5, 127.8, 128.5, 129.2, 130.1, 133.7, 135.5, 136.0 139.2, 149.2 and 164.7.
Anal. Calc. For C20 : C, 82.16; H, 6.89 %. Found: C, 82.17; H, 6.87 %.
1
H
20
O
2
Ethyl (2E)-3-{4-[(E)-2-(4-methylphenyl)ethenyl]phenyl}prop-2-enoate
o
1
(
6.4): Brown solid. mp 124-126 C. H NMR (400 MHz, DMSO-d6): δ 1.70 (t, 3H, CH
3
), 2.71
(
s, 3H, Me), 4.22 (q, 2H, CH ), 6.70 (d, J = 16.0 Hz, 1H, trans-olefinic H), 6.75 (d, J = 16.2 Hz,
2
1
8
H, trans-olefinic H), 7.07 (m, 4H, ArH), 7.25 (d, J = 7.8 Hz, 1H, trans-olefinic H), 7.33 (d, J =
.0 Hz, 2H, ArH), 7.49 (d, J = 16.4 Hz, 2H, ArH), 7.79 (d, J = 16.8 Hz, 1H, trans-olefinic H).
13C NMR (100 MHz, DMSO-d6): δ 19.9, 24.9, 65.2, 113.4, 127.0, 127.4, 127.9, 128.5, 128.6,
29.0, 132.0, 132.5, 136.2, 137.5, 149.2 and 162.5. Anal. Calc. For C20 : C, 82.16; H, 6.89
. Found: C, 82.17; H, 6.87 %.
1
H
20
O
2
%
2
.5. General procedure for the double olefination via Horner-Emmons and Wittig
Transformations (Tables 7a-7b)
1
5

1
6
2
.5.1 Double Horner-Emmons: In an oven dry nitrogen-flushed shlunck tube was placed a
mixture of dialdehyde (1.0 mmol), ethyl 2-(diethylphosphoryl)acetate (2.1 mmol), [PAIM][NTf
4 mmol), and [BMIM][PF ] (8 mL), and the reaction was heated to 65-70 °C for 6-7 h. After
2
]
(
6
completion (TLC monitoring) the crude reaction mixture was extracted 3 times with
hexane/EtOAc (80:20), dried (magnesium sulfate), and the solvent was removed under vacuum
to furnish the crude product which was then purified by flash column chromatography with
hexane/ethyl acetate (80:20).
2
.5.2. Double Wittig: An oven-dried reaction tube equipped with a magnetic stirrer bar was
charged with a mixture of dialdehyde (1.3 mmol), benzyltriphenylphosphonium bromide (2.2
mmol), [PAIM][NTf ] (4 mmol) and [BMIM][PF ] (7 mL). The reaction mixture was stirred and
2
6
heated at 60-70 °C under a nitrogen atmosphere for 7-8 hours. After completion (TLC
monitoring) the crude reaction mixture was extracted 3 times with hexane/EtOAc (80:20), dried
(magnesium sulfate), and the solvent was removed under vacuum to furnish the crude product
which was then purified by flash column chromatography with hexane/ethyl acetate (80:20).
o
1
Diethyl (2E,2'E)-3,3'-benzene-1,4-diyl-bis-prop-2-enoate(7a.1): White solid. mp 90-92 C. H
NMR (400 MHz, DMSO-d6): δ 1.67 (t, 6H, CH
3
), 4.33 (q, 4H, CH ), 6.99 (d, J = 16.2 Hz, 2H,
2
trans-olefinic Hs), 7.04 (d, J = 16.0 Hz, 2H, trans-olefinic Hs), 7.25-7.37 (m, 4H, ArH). 13C
NMR (100 MHz, DMSO-d6): δ 20.1, 65.0, 117.0, 127.4, 137.5, 148.8 and 164.2. Anal. Calc.
For C16
H
18
4
O : C, 70.06; H, 6.61 %. Found: C, 70.08; H, 6.63 %.
2
8
o
Diethyl (2E,2'E)-3,3'-benzene-1,3-diyl-bis-prop-2-enoate (7a.2): White solid. mp 56-58 C.
1H NMR (400 MHz, DMSO-d6): δ 1.35 (t, 6H, CH
), 4.18 (q, 4H, CH ), 7.03 (d, J = 16.0 Hz,
H, trans-olefinic Hs), 7.07 (d, J = 16.4 Hz, 2H, trans-olefinic Hs), 7.20-7.32 (m, 3H, ArH), 7.34
3
2
2
1
3
(
s, 1H, ArH). C NMR (100 MHz, DMSO-d6): δ 18.1, 65.1, 114.8, 126.2, 127.5, 128.4, 134.8,
1
45.0 and 167.7. Anal. Calc. For C16
H
18
4
O : C, 70.06; H, 6.61 %. Found: C, 70.04; H, 6.62 %.
1
8
o
1
1
,4-bis[(E)-2-phenylethenyl]benzene(7b.1): Pale yellow solid. mp 260-262 C. H NMR (400
MHz, DMSO-d6): δ 7.07 (d, J = 16.0 Hz, 2H, trans-olefinic Hs), 7.13 (d, J = 16.0 Hz, 2H, trans-
1
3
olefinic Hs), 7.39-7.50 (m, 6H, ArH), 7.50-7.63 (m, 8H, ArH). C NMR (100 MHz, DMSO-d6):
1
6

1
7
δ 124.9, 125.5, 126.2, 126.7, 127.2, 127.6, 128.3, 129.0, 131.1 and 132.3. Anal. Calc. For
18: C, 93.57; H, 6.43 %. Found: C, 93.56; H, 6.42 %.
22
C H
,3-bis[(E)-2-phenylethenyl]benzene(7b.2):18 Yellow solid. mp 178-180 C. H NMR (400
o
1
1
MHz, DMSO-d6): δ 6.89 (d, J = 16.2 Hz, 2H, trans-olefinicHs), 7.00 (d, J = 16.4 Hz, 2H, trans-
olefinic Hs), 7.29 (t, 1H, ArH), 7.37-7.49 (m, 10H, ArH), 7.52 (d, J = 8.2 Hz, 2H, ArH), 7.66 (s,
1
3
1
1
6
H, ArH). C NMR (100 MHz, DMSO-d6): δ = 124.2, 124.8, 125.6, 126.0, 126.3, 126.7, 127.8,
29.5, 130.1, 132.0 and 133.0. Anal. Calc. For C22
.42 %.
H18: C, 93.57; H, 6.43 %. Found: C, 93.58; H,
2
.6. Recycling and reuse of the IL solvents
The recovered brown-colored [BMIM][X] (also containing [PAMI][NTf ] and its
2
o
conjugate acid) was dried overnight under vacuum at 60 C and reused directly in the next
cycle(s), after which it was collected and set aside for recovery and recycling as follows: the
combined brown-colored IL recovered from several runs were dissolved in dry MeCN and
filtered through Celite to remove insoluble dark (brown/black) particles. After removal of
solvent from the filtrate under vacuum, the recycled IL was dried overnight under vacuum at 60
oC and reused in subsequent runs. Control experiment showed that addition of fresh
[
PAIM][NTf ] to recycled IL was necessary in order to reach the reported yields.
2
3
3
.
Results and Discussion
.1.
Suzuki and Heck cross-coupling reactions (Tables 1-2)
The utility of [PAIM][NTf
2
]/Pd(OAc) /[BMIM][X] system to effectively promote the Suzuki and
2
Heck cross-coupling reactions without using any other additives was examined by reacting various
aryl(heteroaryl)bromides with aryl(heteroaryl)-boronic acids or with various substituted ethenes and
enoates (Figures 2-3), and the results are summarized in Tables 1-2. Isolated yields for the Suzuki
reaction were in the 92% to 76% range under relatively mild conditions and with short reaction times.
Slightly lower conversions were observed in cases where recycled ILs had been used. For the Heck
1
7

1
8
reactions isolated yields were in 91% to 74% range, with lower conversions observed in recycled ILs.
Longer reactions times and slightly higher temperatures were employed in the Heck reaction in
order to achieve optimal conversions. Formation of purely trans-alkenes in all cases was evident
based on magnitude of the H/H coupling. Although isolated yields obtained in [BMIM][PF
versus [BMIM][BF ] were typically comparable, recycled [BMIM][PF ] appeared to perform
better (see the recycling and reuse section).
6
]
4
6
Figure 2. Suzuki cross-coupling in ILs
Figure 3. Heck cross-coupling in ILs
3
.2.
Tandem Wittig- Suzuki Transformations (Tables 3a-3b)
The [PAIM][NTf
under mild conditions, with substituted benzaldehydes and 4-bromobenzyl-PhP
bromomethyl-PhP bromide salts respectively (Figure 4). Subsequent addition of
aryl(heteroaryl)boronic acids along with catalytic amounts of Pd(OAc) induced the Suzuki
2
]/[BMIM][X] system proved efficient in promoting the Wittig reaction
3
or
3
2
reaction which led to the isolation of a small library of high value trans-alkenes in isolated yields
ranging from 80 to 65%. The lower conversions were typically those obtained in the recycled
ILs.
1
8

1
9
Figure 4. Wittig-Suzuki tandem reactions
3
.3.
Tandem Wittig- Heck Transformations (Table 4)
The [PAIM][NTf
2
]/[BMIM][X] system also proved efficient in promoting the Wittig-
][I] salt, the
Heck tandem reactions. When benzaldehydes were allowed to react with [Me-PPh
3
Wittig olefination products were formed, and subsequent introduction of PhI along with the Pd-
catalyst induced the Heck cross-coupling (Figure 5), leading to the isolation of substituted trans-
diphenyl-ethenes in yields ranging from 78% to 65%.
Figure 5. Wittig-Heck tandem reactions
3
.4.
Horner-Emmons-Suzuki and Horner-Emmons-Heck reactions (Tables 5-6)
Horner-Emmons (HE) olefinations were effected in [PAIM][NTf ]/[BMIM][X] by reacting
2
isomeric bromo-benzaldehyde with diethylphosphonate under moderate heating. Subsequent
addition of the boronic acid and the Pd-catalyst induced the Suzuki reaction (Figure 6a). The
1
9

2
0
resulting biaryl-enoates were isolated in 78% to 70% yield, with lower yields obtained in
recycled IL. Following a similar protocol the HE-Heck sequence were performed (Figure 5b) by
addition of substituted styrenes in place of the boronic acids in 60-70% isolated yields.
Figure 6a. Horner-Emmons-Suzuki tandem reactions
Figure 6b. Horner-Emmons-Heck tandem reactions
3
.5.
Double olefination via Horner-Emmons and Wittig reactions (Tables 7a-7b)
The feasibility to perform bis-olefination in [PAIM][NTf
reacting isomeric phthalaldehydes with diethyl-phosphonate and with benzyl-PPh
representative cases, the bis-propenoates and the bis-styryl-derivatives were isolated in acceptable yields.
2
]/[BMIM][X] was explored by
3
bromide (Figure 7). In
2
0

2
1
Figure 7. Bis-olefination feasibility study
4
.
Recycling and reuse of the IL solvent
The yield data summarized in Tables along with table footnotes give an overall sense of
the feasibility to employ recycled/reused [BMIM][X] in the described transformations. But to get
a better sense of how far this could go, one entry out of each table was selected and the reaction
was repeated four additional times in the same IL to compare isolated yields. The outcomes are
rd
summarized in chart 1. It can be seen that there is a sharp decrease in yields beyond the 3 cycle
rd
which is likely due to accumulation of tar and impurities, suggesting that beyond the 3 cycle
either fresh IL must be employed or the used ILs should be put through a clean-up/regeneration
process (see experimental). Similar observations were made previously in Pd-catalyzed Heck and
Sonogashira reactions in ILs [6b, 9]. Data in chart 1 shows that whereas initially the conversions
in [BMIM][PF
6
] and [BMIM][BF
4
] are comparable (slightly better in the former), [BMIM][PF ]
6
appears to be “more pliable” and performs better when re-used.
Chart 1. Recycling and reuse of [BMIM][X]
2
1

2
2
1
00
1
00
Table 2, entry 8
Table 1; entry 10
8
6
4
2
0
0
0
0
0
8
6
0
0
40
20
0
1
2
3
4
5
1
2
3
4
5
80
60
40
20
0
1
00
Table 4; entry 2
Table 3a, entry 5
8
6
4
2
0
0
0
0
0
1
2
3
4
5
1
2
3
4
5
Footnotes. X axis: number of cycles; Y axis: isolated yields; red: [BMIM][PF
BMIM][BF
6
]; blue:
[
4
]
5
.
Conclusion
2
2

2
3
The efficacy of [PAIM][[NTf
cross-coupling reactions without the need for any other additives is demonstrated. The
PAIM][[NTf ]/[BMIM] system also proved effective for the Wittig and Horner-Emmons
2
]/[BMIM][X]/Pd-catalyst system in the Suzuki and Heck
[
2
olefinations employing readily available phosphonium salts. These findings led to the
development of simple to perform one-pot Wittig-Suzuki, Wittig-Heck, Horner-Emmons-Suzuki,
and Horner-Emmons-Heck hyphenated transformations, and the study the scope of these
transformations which resulted in the synthesis of a diverse pool of biaryls, diaryl-ethenes, and
aryl-enoates. The feasibility to recycle and re-use the IL solvent was also investigated.
Table 1. Suzuki coupling reaction with [PAIM][NTf ]/[BMIM][X]
2
Time
Entry
No.
Yield
[%]
Producta
ArB(OH)
2
Ar-Br
IL
h]b
[
O
O
[
[
[
BMIM][PF
6
6
6
]
]
]
3
84c
82c
1
B(OH)2
B(OH)2
Br
O
O
O
O
BMIM][PF
BMIM][PF
3
2
Br
N
O
3
2
80d
82d
3
4
B(OH)2
B(OH)2
Br
N
Br
[
BMIM][BF
BMIM][BF
4
]
Br
[
4
]
3
80d
5
B(OH)2
N
N
[
BMIM][BF
BMIM][BF
4
4
]
]
2
2
87c
86c
6
7
B(OH)2
B(OH)2
Br
O
Br
[
O
2
3

2
4
O
O
O
O
78e
[
BMIM][BF
BMIM][BF
4
]
3
3
2
8
9
B(OH)2
B(OH)2
B(OH)2
Br
Br
O
O
76e
[
4
]
1
0
Br
[BMIM][PF
6
]
92c
[
BMIM][PF
6
6
6
]
]
]
2
2
3
90c
89d
84e
1
1
1
2
B(OH)2
B(OH)2
Br
O
O
Br
Br
[BMIM][PF
[BMIM][PF
O
O
1
3
B(OH)2
O
O
a
Reaction conditions: ArB(OH) (1.1 mmol), Ar-Br (1.3 mmol), basic-IL (4 mmol), [BMIM][X] (7 mL),
2
b
o
c
d
and Pd(OAc) (5 mol %); Oil bath temperature 60 C; Yield employing fresh IL; Yield using recycled
2
nd
e
rd
IL (2 cycle); Yield using recycled IL (3 cycle)
Table 2. Heck coupling reaction with [PAIM][NTf
Entry
2
]/[BMIM][X]
Time
Yield
[%]
Producta
Substrate 1
Substrate 2
IL
No.
h]b
[
S
S
78c
[
BMIM][PF
6
6
]
]
5
1
Br
S
S
83c
[BMIM][PF
6
2
Br
2
4

2
5
N
S
S
79c
[
BMIM][PF
6
]
6
6
3
4
Br
N
N
N
[
BMIM][BF
BMIM][BF
4
]
80c
Br
S
S
[
4
]
6
74d
5
Br
O
O
75d
6
7
O
[
BMIM][BF
4
]
6
5
Br
[
BMIM][PF
6
]
89d
[
BMIM][PF
BMIM][PF
6
6
]
]
4
4
91c
90c
8
9
Br
[
Br
OEt
O
Cl
Br
O
77d
[
BMIM][BF
BMIM][BF
4
]
7
6
7
1
0
1
O
H
Cl
H
O
O
[
4
]
80c
74e
1
1
O
O
Br
Br
O
O
O
OEt
O
O
[
6
BMIM][PF ]
2
O
H
O
2
5

2
6
H
O
O
O
[
BMIM][PF
6
]
6
6
76e
78e
1
1
3
4
Br
O
O
O
H
O
4
[BMIM][BF ]
Br
O
a
Reaction conditions: substrate 1 (1.0 mmol), substrate 2 (1.2 mmol), basic-IL (4 mmol), [BMIM][X]
b
o
c
d
(
7 mL) and Pd(OAc) (6 mol %); Oil bath temperature 70 C; Yield employing fresh IL; Yield using
2
nd
e
rd
recycled IL (2 cycle); Yield using recycled IL (3 cycle)
Table 3a. Tandem Wittig-Suzuki reaction with [4-bromobenzyl-PPh
3
][Br], [PAIM][NTf ]/
2
[BMIM][X]
Total
Entry
No.
Time
Yield
[%]
Producta
Substrate 1
Substrate 2
IL
[
h]b
O
75c
1
H
B(OH)2
[BMIM][PF
6
]
8
O
2
3
H
B(OH)2
B(OH)2
[BMIM][PF
6
]
8
8
70d
O
H
[BMIM][BF
4
]
68c
O
O
2
6

2
7
O
H
4
5
B(OH)2
B(OH)2
[BMIM][BF
4
]
8
8
65d
Cl
Cl
O
80c
H
[BMIM][PF
6
]
a
Reaction conditions: substrate 1 (1.3 mmol), substrate 2 (1.4 mmol), basic-IL (4 mmol), phosphonium
b
o
c
salt (1.1 mmol), [BMIM][X] (6 mL), and Pd(OAc) (10 mol %); Oil bath temperature 60-65 C; Yield
employing fresh IL; Yield using recycled IL (2 cycle)
2
d
nd
Table 3b. Tandem Wittig-Suzuki reaction with [bromomethyl-PPh
3
][Br], [PAIM][NTf ]/
2
[BMIM][X]
Total
Entry
No.
Time
Yield
[%]
Producta
Substrate 1
Substrate 2
IL
[
h]b
O
O
O
68e
Bmim-PF
Bmim-PF
6
6
7
1
H
B(OH)2
O
O
O
N
O
O
70c
6
6
2
3
H
B(OH)2
N
O
71e
Bmim-BF
Bmim-BF
4
4
H
O
B(OH)2
7
80c
4
H
B(OH)2
2
7

2
8
O
O
O
O
74d
Bmim-PF
Bmim-PF
6
6
5
5
5
6
H
H
B(OH)2
B(OH)2
82c
O
O
O
S
79c
78c
74d
S
S
Bmim-BF4
Bmim-BF4
7
7
7
8
B(OH)2
B(OH)2
O
N
H
S
H
H
O
N
Bmim-PF
6
7
9
B(OH)2
a
Reaction conditions: substrate 1 (1.0 mmol), substrate 2 (1.2 mmol), phosphonium salt (1.1 mmol),
b
o
c
basic-IL (4 mmol), [BMIM][X] (5 mL) and Pd(OAc) (10 mol %); Oil bath temperature 60-65 C; Yield
employing fresh IL; Yield using recycled IL (2 cycle); Yield using recycled IL (3 cycle)
2
d
nd
e
rd
Table 4. Tandem Wittig-Heck reaction with [methyl-PPh
3
][I], [PAIM][NTf
2
]/[BMIM][X]
Total
Time
Entry
No.
Yield
[%]
Producta
Substrate 1
Substrate 2
IL
[
h]b
O
H
I
[
BMIM][BF
BMIM][BF
4
]
]
7
65d
78c
1
O
H
I
I
[
4
8
8
2
3
4
O
H
74d
[
BMIM][PF
BMIM][PF
6
6
]
]
O
O
O
I
[
8
70e
H
Cl
Cl
2
8

2
9
O
I
[BMIM][PF
6
]
8
76c
5
H
a
Reaction conditions: substrate 1 (1.3 mmol), substrate 2 (1.0 mmol), phosphonium salt (1.2 mmol),
b
o
c
basic-IL (3 mmol); [BMIM][X] (6-7 mL); Pd(OAc) (10 mol %); Oil bath temperature 65 C; Yield
employing fresh IL; Yield using recycled IL (2 cycle); Yield using recycled IL (3 cycle)
2
d
nd
e
rd
Table 5. Tandem Horner-Emmons-Suzuki sequence in [PAIM][NTf
2
]/[BMIM][X]
Total
Time
Entry
No.
Yield
[%]
Producta
Substrate 1
Substrate 2
IL
[
h]b
O
O
O
O
O
[BMIM][PF
6
6
6
]
]
]
6
78c
72d
70e
1
H
B(OH)2
Br
O
O
Br
Br
H
H
2
3
B(OH)2
B(OH)2
[BMIM][PF
[BMIM][PF
6
7
O
O
2
9