Cross coupling in water: Suzuki-Miyaura vinylation and difluorovinylation of arylboronic acids

Article abstract of DOI:10.1039/b924772f

A general and efficient protocol for the Suzuki-Miyaura coupling of aryl boronic acids with vinylmesylate or difluorovinylmesylate or Cl ₂CCF₂ in water or water/n-butanol is reported, utilizing Na₂PdCl₄ (1 mol%) and a highly water-soluble fluorenylphosphine (CataCXium F sulf).

Full text of DOI:10.1039/b924772f

Retraction
Cross coupling in water: Suzuki–Miyaura vinylation and
difluorovinylation of arylboronic acids
Jan Pschierer, Natalie Peschek and Herbert Plenio
Green Chem., 2010, 12, 636 (DOI: 10.1039/b924772f).
We, the named authors, hereby wholly retract this Green Chemistry article.
Signed: Jan Pschierer, Natalie Peschek and Herbert Plenio, Germany,
September 2010.
Retraction endorsed by Sarah Ruthven, Editor.
Retraction published 15th September 2010

PAPER
www.rsc.org/greenchem | Green Chemistry
Cross coupling in water: Suzuki–Miyaura vinylation and difluorovinylation
of arylboronic acids†
Jan Pschierer, Natalie Peschek and Herbert Plenio*
Received 24th November 2009, Accepted 6th January 2010
First published as an Advance Article on the web 8th February 2010
DOI: 10.1039/b924772f
A general and efficient protocol for the Suzuki–Miyaura coupling of aryl boronic acids with
=
vinylmesylate or difluorovinylmesylate or Cl2C CF2 in water or water/n-butanol is reported,
utilizing Na2PdCl4 (1 mol%) and a highly water-soluble fluorenylphosphine (CataCXium F sulf).
Various substituted styrenes are important monomers for poly-
merization reactions,1 and are also applied in Mizoroki–Heck
coupling,2 (asymmetric) hydrosilylation,3 hydroformylation,4
hydroamination5 or olefin-metathesis reactions.6,7 The classic
routes to vinylarenes rely on the elimination of activated leaving
groups, the carbonyl olefination or the partial reduction of
terminal alkynes. Recently two methods based on cross-coupling
methodology using either the reaction of a vinylmetallic donor
and an aryl halide (or pseudohalide) or the reaction of an
arylmetallic donor and a vinyl halide (or pseudohalide) have seen
great progress and subsequently the palladium- (and nickel-)
catalyzed vinylation of aryl halides was reviewed by Denmark
and Butler.8
Different phosphine ligands (see Fig. 2) were tested as well as
different bases, Pd-sources and solvents (Table 1). As reported
in a previous publication19 the CataCXium F sulf ligand (Fig. 1)
used in a Pd/ligand ratio of 1 : 2 in pure water turned out to be
the most active catalyst (Table 1, entry 3).
Fig. 1 CataCXium F sulf.
The better developed approach to the synthesis of styrenes
utilizes nucleophilic vinyl transfer reagents via Heck (ethene),8
Kumada (vinyl-MgR),9,10 Stille (vinyl-SnR3),11 Suzuki–Miyaura
(vinyl-BR2),12-14 and Hiyama (vinyl-SiR3) reactions.15 The elec-
tronically inverse reaction of vinyl electrophiles with arylmetallic
donors is less often applied,16-19 which is probably also due to
the lack of suitable vinyl transfer reagents. Significant progress
was recently reported by Skrydstrup et al., who introduced vinyl
tosylate as a convenient and stable transfer reagent in palladium
catalyzed reactions with various boronic acids and esters—albeit
the desired products are formed in less than quantitative yields,
despite the use of high catalyst loading (5 mol%).20
Initially, we tested the coupling reactions of vinyl tosylate with
tolylboronic acid and the sterically hindered 2-naphthylboronic
acid under the specified conditions (Table 2, entries 1, 2, 4,
6–8) at 0.5 mol% [Pd] loading. The respective vinylarenes
Table 1 Optimization of reaction conditions for vinyl transfer using
vinyl mesylate (mesylate or methanesulfonate = Ms)
We recently reported that a water-soluble disulfonated fluo-
renylphosphine/palladium complex displays excellent activities
in Suzuki–Miyaura reactions of various aryl chlorides when
using water21,22 or water/n-butanol23,24 as solvents.25 This pro-
tocol appears to be especially efficient for substrates containing
difficult (potentially palladium coordinating) functional groups
and unreactive C–X bonds.
We report here a simple coupling protocol utilizing Na2PdCl4
and the water-soluble and commercially available fluorenylphos-
phine (cataCXium F sulf)26 in vinylation reactions of aryl
boronic acids utilizing vinyl mesylate, 2,2-difluorovinylmesylate
or 1,1-dichloro-2,2-difluoroethene.
Entry Ligand Ratio Pd/ligand Pd source Base
Conversiona
1
2
2
1
3
1
1
1
1
1
2
2
1 : 2
1 : 2
Na2PdCl4 K2CO3 71%b
PdCl2
2
3
4
5
6
7
8
9
K2CO3 12%b
1 : 2
1 : 2
1 : 1
no ligand
1 : 2
1 : 2
1 : 2
1 : 1
1 : 2
Na2PdCl4 K2CO3 99%b
Na2PdCl4 Cs2CO3 87%c
Na2PdCl4 K2CO3 27%b
Na2PdCl4 K2CO3 0%b
PdCl2
K2CO3 46%b
Na2PdCl4 NaOH 93%b
Na2PdCl4 K2CO3 99%d
Na2PdCl4 K2CO3 11%b
Na2PdCl4 NaOH 67%b
10
11
Anorganische Chemie im Zintl-Institut, TU Darmstadt, Petersenstr. 18,
64287, Darmstadt, Germany. E-mail: plenio@tu-darmstadt.de
† Electronic supplementary information (ESI) available: Contains spec-
tra of all newly synthesized compounds. See DOI: 10.1039/b924772f
a Determined via gas chromatography (heptadecane, internal standard),
average of two runs. b Solvent water. c Solvent dioxane. d Solvent n-
butanol/water 3/1.
636 | Green Chem., 2010, 12, 636–642
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©

Table 2 Suzuki–Miyaura coupling of vinyl mesylate with Pd/cataCXium F sulf
Entry
1
Boronic acid
Product
Mol % catalyst
Isolated yield [%]
1.0
99
99
99
87
0.5a
0.5
0.25
2
1.0
99
99
99
83
0.5a
0.5
0.25
3
4
1.0
0.5
0.25
99
84
42
FcB(OH)2
1.0
90
99
76
1.0a
0.5
0.25
1.0
21
5
6
49% (99%)b
1.0
99
81
95
49
0.5
0.5a
0.25
7
8
1.0
99
79
91
49
0.5
0.5a
0.25
1.0
0.5
0.5a
99
84
94
Conditions: 1.0 mmol vinyl mesylate, 1.2 mmol boronic acid, 2.5 mmol K2CO3, degassed water (5.0 mL), 95 ◦C, reaction time: 16 h, catalyst stock
solution in water (c (Pd) = 1.0 mol %/mL, Na2PdCl4/cataCXium F sulf 1 : 2. Fc = ferrocenyl.a Vinyl tosylate was used. b Quantitative formation of
vinylfuran, but due to the low b.p. (86 ◦C) the isolated yield is modest for the small scale reactions performed. Yields correspond to isolated material
after chromatography (silica), pentane–CH2Cl2 = 9/ 1.
With
a view to the high catalytic efficiency of the
Pd/cataCXium F sulf system we decided to use the even less
reactive, but more atom-economical vinyl mesylate as the vinyl
transfer reagent instead of the vinyl tosylates.27 Vinyl mesylate
was prepared in 78% yield on a multigram scale analogous to
the synthesis of vinyl tosylate,20 using THF and freshly distilled
mesylchloride (Scheme 1).
Fig. 2 Phosphine ligands.
were isolated in virtually quantitative yields, which compares
favorably with the 5 mol% loading of a ferrocenyl palladium
phosphine complex employed previously.20
Scheme 1 Synthesis of vinyl mesylate.
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Table 3 Suzuki–Miyaura coupling of difluorovinyl mesylate with
We next examined the Suzuki coupling of various aryl-
and heteroarylboronic acids with vinyl mesylate in more detail
(Table 1). Catalyst loadings of between 0.5–1 mol% are sufficient
to effect quantitative conversion of the boronic acids tested.
Due to the lower reactivity of vinyl mesylate (compared to vinyl
tosylate) this substrate requires ca. twice the catalyst loading. All
reactions were carried out in water as the only solvent. The use
of water/n-butanol 1/3 as the reaction solvent gives the same
cross coupling yields, since the small boronic acids as well as the
vinyl mesylate employed here, appear to have sufficient water
solubility. In the aqueous reaction mixtures the nature of the
base does not have much influence on the reaction outcome and
we therefore always used the cheap K2CO3. Sterically hindered
(Table 1, entries 2, 6, 7) and heterocyclic boronic acids (Table 1,
entries 3, 5, 7, 8) require 1 mol% [Pd] loading. For unhindered
boronic acids 0.5 mol% are sufficient, while for a few substrates
as little as 0.25 mol% give excellent results (Table 1, entries 1, 2).
For the coupling reactions reported here we also optimized the
amount of boronic acid. The present reaction protocol requires
only a modest excess (1.2 equiv.) of the boronic acid to achieve
full conversion of vinyl mesylate, while less boronic acid leads
to significantly decreased coupling yields. Nonetheless, even
for the Suzuki coupling of thiophene and furanboronic acid,
which are both prone to hydrodeboronation reactions, the same
amount of boronic acid as for the hydrolytically stable acids is
sufficient. Despite using a small excess of boronic acid, we have
not experienced purification problems caused by deboronated
products.28
Rather than minimizing catalyst loading it is more useful,
from a practical point of view, to avoid time and solvent con-
suming chromatographic purifications of the reaction products.
This can be achieved here by applying a slightly higher catalyst
loading—1 mol% of water-soluble Na2PdCl4 and 2 mol% of
cataCXium F sulf—to effect the quantitative vinylation of the
boronic acids for all entries in Table 1. The reaction products
are then simply extracted with n-butanol or MTBE from the
aqueous reaction phase, since the various salts and excess
boronic acid remain dissolved in water. The evaporation of the
solvent used for extraction under reduced pressure normally
affords pure (> 99% purity) cross coupling products.
Pd/cataCXium F sulf
Mol %
catalyst
Isolated
yield [%]
Entry
1
Boronic acid
Product
1.0
0.5
99
65
2
3
1.0
0.5
89
27
1.0
0.5
81
43
4
5
FcB(OH)2
1.0
0.5
89
67
1.0
0.5
93
73
Conditions: 1.0 mmol difluorovinyl mesylate, 1.2 mmol boronic acid,
2.5 mmol K2CO3, degassed water (5.0 mL), 95 ◦C, reaction time:
16 h, catalyst stock solution in water (c (Pd) = 1.0 mol %/mL,
Na2PdCl4/cataCXium F sulf 1 : 2. Fc = ferrocenyl, Yields correspond to
isolated material after chromatography (silica), pentane–CH2Cl2= 5/1.
Notable in the present set of substrates is the facile synthesis
of vinylferrocene (Table 1, entry 4) in good yields according
to the reaction protocol reported here, as compared to the
classical synthesis via acetylferrocene29 or more recently via
ethynylferrocene.30 Vinylferrocenes are important precursors for
polymers with variable electronic properties;31,32 the protocol
reported here provides a simple one step synthesis.
The reaction conditions used in the Suzuki–Miyaura coupling
of vinyl mesylate were extended to difluorovinyl mesylate. The
introduction of a fluorinated (vinyl) group is of significant inter-
est for pharmaceutical and agrochemical products.33,34 Excellent
cross coupling yields were achieved using 1.0 mol % [Pd] catalyst
for activated boronic acids (Table 3, entry 1), heteroaryl boronic
acids (Table 3, entry 2) and sterically demanding boronic acids
(Table 3, entry 3, 5).
commercially available chlorofluoroolefins.35 The pioneering
work of Burton on CF2 transfer reagents36 also established
=
Negishi and Suzuki coupling via CF2 CClZnCl for the syn-
=
thesis of Ar,Ar¢C CF2 type species under strictly anhydrous
conditions.37
◦
=
The reagent F2C CCl2 used here is very volatile (bp 19 C),
but easy to handle after preparing a stock solution in cold
n-butanol. Almost the same reaction protocol as described
=
for the vinyl mesylates was utilized for Cl2C CF2. However,
with the poorly water-soluble alkene the coupling reactions
need to be carried out in water/n-butanol mixtures instead of
water to obtain good results. Excellent substrate conversions
were achieved using 1 mol % [Pd] catalyst for a variety of
activated boronic acids (Table 4, entry 1), sterically demanding
boronic acids (Table 4, entry 2, 3) and heteroboronic acids
(Table 4, entry 4). Using 1.2 equiv. of boronic acid it is possible to
Due to the facile difluorovinyl-group transfer reactions
we became interested in testing other fluorinated building
blocks as useful substrates for the Suzuki–Miyaura coupling
and 1,1-dichloro-2,2-difluoroethene (R-1112a) is one of many
638 | Green Chem., 2010, 12, 636–642
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©

=
Table 4 Suzuki–Miyaura coupling of Cl2C CF2 with aryl boronic
Table 4 (Contd.)
acids
Mol %
catalyst
Isolated
yield [%]
Mol %
catalyst
Isolated
yield [%]
Entry
9
Boronic acid
Product
Entry
1
Boronic acid
Product
1.0
84
1.0
0.5
99
67
=
Conditions: 1.0 mmol Cl2C CF2, 1.2 mmol boronic acid, 2.5 mmol
K2CO3, degassed water (1.5 mL), n-butanol (4.5 mL), 95 ◦C, reaction
time: 16 h, catalyst stock solution in water (c (Pd) = 1.0 mol %/mL,
Na2PdCl4/cataCXium F sulf 1 : 2. Fc = ferrocenyl, Yields correspond
to isolated material after chromatography (silica), pentane–CH2Cl2=
5/1.a 2.2 equiv. boronic acid.
2
3
1.0
0.5
99
64
1.0
0.5
89
56
selectively introduce a single aryl group (Table 4, entries
1–5), while in the presence of 2.2 equiv. of boronic acid two
identical aryl groups are introduced (Table 4, entries 6, 7) in
a single reaction step. A second and different aryl group can
be easily added by repeating the coupling protocol with the
isolated and purified monarylated alkenes ArClC CF2. The
respective ArAr¢C CF2 products are isolated in excellent yields
4
5
1.0
0.5
96
37
=
=
over the two steps (Table 4, entries 8, 9).
In conclusion, we have developed a simple Suzuki protocol for
the aqueous coupling of vinyl mesylate, difluorovinyl mesylate
and 1,1-dichloro-2,2-difluoroethene with various arylboronic
acids. Catalyst loadings between 0.25 and 1 mol % Na2PdCl4
and twice as much of the disulfonated fluorenylphosphine
(cataCXium F sulf) in water or n-butanol/water using a simple
base (K2CO3) afford the respective cross-coupling products in
excellent yields.
1.0
0.5
0.25
99
89
70
6
1.0a
0.5a
99
64
Experimental section
General experimental
7
8
1.0a
0.5a
99
65
All chemicals were purchased as reagent grade from commercial
suppliers and used without further purification, unless otherwise
noted. Used solvents (water, n-butanol; all technical grade) were
deaerated via freeze and thaw technique (3¥). For cross coupling
reactions under anhydrous conditions, n-butanol (technical
1.0
87
˚
grade, dried over molecular sieves, 4 A) was used. Potassium
carbonate, used in cross coupling reactions, was technical grade.
All “phosphines” in this publication were used in the form of
their air stable phosphonium salts and deprotonated in situ
during the catalyst preparation. All experiments were carried
out under an argon atmosphere, unless otherwise noted.
Proton (1H NMR) and carbon (13C NMR) nuclear magnetic
resonance spectra were recorded on Bruker ARX 300 at
300 MHz respectively 75 Hz or on Bruker DRX 500 at 500 MHz,
125.75 MHz respectively, at 293 K. The chemical shifts are
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1
given in parts per million (ppm) on the delta scale (d) and are
referenced to tetramethylsilane (0 ppm). Melting points were
recorded on an uncorrected Stuart SMP10 instrument. Mass
spectra were recorded on a Finnigan MAT 95 magnetic sector
spectrometer. Thin layer chromatography (TLC) was performed
using Fluka silica gel 60 F 254 (0.2 mm) on alumina plates. Silica
gel columns for chromatography were prepared with E. Merck
silica gel 60 (0.063–0.20 mesh ASTM). GC experiments were
run on a Clarus 500 GC with autosampler and FID detector.
2.3 g of the title compound (58%) as a colorless oil. H NMR
(300 MHz, CDCl3) d 6.06 (dd, 1H, J = 12.6, 4.1 Hz), 2.47 (s,
3H). 13C { H} NMR (75 MHz, CDCl3) d 156.9 (dd, JCF = 256.4,
1
266.2 Hz), 100.8 (q, JCF = 63.2 Hz), 30.3. HRMS (m/z): calcd
for C3H4F2O3S: 157.9845; found: 157.98693. Viscous oil.
Suzuki–Miyaura coupling of vinyl tosylates/-mesylates or
difluorovinyl mesylates with Pd/cataCXium F sulf
Preparation of the catalyst stock solution. [Na2PdCl4] (14.7 mg,
0.05 mmol), phosphine ligand (0.1 mmol) and K2CO3 (56 mg,
0.4 mmol) were placed in a Schlenk tube under argon, evacuated
and backfilled with Ar thrice. Degassed water (5.0 mL) was
added and the mixture was stirred at 45 ◦C for 3 h. This stock
solution had a Pd concentration of 0.01 mol L-1.
Column: Varian CP-Sil 8 CB (l = 15 m, di = 0.25 mm, dF
=
1.0 mm), N2 (flow: 17 cm s-1; split 1 : 50); Injector-temperature:
270 ◦C, detec◦tor temperature: 350 ◦C. Temperature program:
isotherm 150 C for 5 min, heating to 300 ◦C with 25 ◦C min-1,
isotherm for 15 min.
Synthesis of vinyl mesylate
General procedure for cross coupling reaction
A solution of 2.5 M n-butyllithium in hexane (39 mL, 98.5 mmol,
1.3 equiv.) was added to 150 mL THF and stirred for 3 h at 35 ◦C
in a 500 mL Schlenk flask. Then the bright yellow reaction
mixture was cooled to -78 ◦C. A solution of mesylchloride
(8.55 g, 75 mmol, 1 equiv.) in THF was added dropwise with a
syringe over a period of 20 min. Then the reaction mixture was
stirred for 30 min at -78 ◦C. Afterwards it was allowed to warm
to room temperature and stirred for another 1 h. The reaction
solution was poured into 200 mL MTBE and 100 mL of iced,
saturated sodium hydrocarbonate was added under vigorous
stirring. The aqueous phase was extracted with MTBE (3 ¥
50 mL) and the combined organic phase was washed with brine
(2 ¥ 50 mL) and dried over sodium sulfate. After concentration
in vacuo the crude product was purified by chromatography
on silica gel using pentane/ethylacetate (40 : 1) as eluent. This
afforded 7.8 g of the title compound (85%) as bright yellow oil.
1H NMR (300 MHz, CDCl3) d 6.82 (dd, J = 5.9, 13.5, 1H), 5.14–
Boronic acid (1.2 mmol), vinyl tosylate or -mesylate (1.0 mmol)
and K2CO3 (345 mg, 2.5 mmol) were placed in a 25 mL Schlenk
tube and evacuated and backfilled with Ar thrice. Degassed
water (5.0 mL) was added together with the appropriate volume
of catalyst stock solution (e.g., 1 mL of the solution prepared
above was added to obtain a catalyst loading of 1 mol %).
The reaction mixture was stirred for 16 h at 100 ◦C and then
cooled to room temperature. The reaction mixture was extracted
with methyl tert-butyl ether (5.0 mL) twice. The combined
organic layers were dried with brine and MgSO4. Conversion
was determined by product isolation: the organic layer was
concentrated in vacuo and the residue was purified by column
chromatography (CH2Cl2–pentane = 1/9 as eluent) to afford
the pure corresponding cross coupling product.
Suzuki–Miyaura coupling of dichlorodifluoroethylene with
Pd/cataCXium F sulf
1
4.89 (m, 2 H), 2.76 (s, 3H). 13C { H} NMR (75 MHz, CDCl3) d
Preparation of the catalyst stock solution. [Na2PdCl4] (14.7 mg,
0.05 mmol), phosphine ligand (0.1 mmol) and K2CO3 (56 mg,
0.4 mmol) were placed in a Schlenk tube under argon. Degassed
water (5.0 mL) was added and the mixture was stirred at 45 ◦C for
3 h. This stock solution had a Pd concentration of 0.01 mol L-1.
139.9, 129.9, 40.9. HRMS (m/z): calcd for C3H6O3S: 122.0032;
found: 122.00322. Viscous oil.
Synthesis of 2,2,2-trifluorethylmesylate
2,2,2-Trifluorethylmesylate was prepared according to the pro-
1
cedure reported by Vastra and Saint-Jalmes38 in 98% yield. H
General procedure for cross coupling reaction
NMR (300 MHz, CDCl3) d 4.34 (dd, 3H, J = 14.1, 6.0 Hz),
=
Boronic acid (1.2 mmol), Cl2C CF2 (1.0 mmol) and K2CO3
1
2.47 (s, 3H). 13C { H} NMR (75 MHz, CDCl3) d 142.7 (q, JCF
=
(345 mg, 2.5 mmol) were placed in a 25 mL Schlenk tube
and evacuated and backfilled with Ar thrice. Degassed water
(1.5 mL) and degassed n-butanol (4.5 mL) were then added
together with the appropriate volume of catalyst stock solution
(e.g., 1 mL of the solution prepared above was added to obtain
a catalyst loading of 1 mol %). The reaction mixture was stirred
for 16 h at 95 ◦C and then cooled to room temperature. The
combined organic layers were dried with brine and MgSO4.
Conversion was determined by product isolation: the organic
layer was concentrated in vacuo and the residue was purified by
column chromatography (CH2Cl2–pentane = 1/9 as eluent) to
afford the pure corresponding cross coupling product.
For analytical approach, the aqueous layer was extracted
with n-butanol (5.0 mL) twice. Methyl tert-butyl ether was used
to extract products with a low boiling point, for example 3-
vinylfuran.
260.8 Hz), 64.5 (q, JCF = 64.2 Hz), 46.2. HRMS (m/z): calcd for
C3H5F3O3S: 177.9934; found: 177.99453. Viscous oil.
Synthesis of 2,2-difluorovinyl mesylate
2,2,2-Trifluorethylmesylate (5.0 g, 28.0 mmol, 1.0 equiv.) was
dissolved in dry THF (50 mL) and cooled to -78 ◦C. A solution
of 2.5 M n-BuLi in hexane (18.0 mL, 46.0 mmol, 2.3 equiv.) was
added drop wise with a syringe over a period of 10 min. The
dark brown solution was stirred for 45 min at -78 ◦C. Hereafter
it was quenched with a mixture of water–THF (1 : 1, 100 mL).
The organic phase was extracted with ethyl acetate (3 ¥ 150 mL).
The combined organic phase was washed with brine (2 ¥ 150 mL)
and dried over sodium sulfate. After concentration in vacuo
the crude product was purified by chromatography on silica
gel using pentane–ethyl acetate (9 : 1) as eluent. This afforded
640 | Green Chem., 2010, 12, 636–642
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=
Cl2C CF2 was used in liquid form as a stock solution in ice
3J = 7.2 Hz, 1H), 7.18–6.93 (m, 1H), 6.01 (dd, J = 25.1, 4.1 Hz,
1
cooled n-butanol. Therefore a specified volume of the gaseous
compound was injected (and dissolved) into a Schlenk tube with
cooled n-butanol using a syringe. When stored in a fridge (4 ◦C),
this stock-solution is usable for many days.
1H). 13C { H} NMR (125.8 MHz CDCl3) d 159.8 (dd, JCF
=
290.0, 281.3 Hz), 139.1 (t, JCF = 6.7 Hz), 134.4, 129.3, 127.6 (t,
JCF = 17.8 Hz), 99.8 (dd, JCF = 27.2 Hz, 4.9 Hz). HRMS (m/z):
calcd for C6H4F2S: 146.0026; found: 126.00543. liquid.
1-(1-m-Xylyl)-2,2-difluoroethene (Table 3, entry 3). 1H NMR
Analytical data of the coupling products
3
(300 MHz, CDCl3) d 7.75 (d,3J = 7.4 Hz, 2H), 7.29 (d, J =
4-Methylstyrene (Table 2, entry 1). HRMS calcd for C9H10:
7.3 Hz, 2H), 6.00(dd, J = 24.6 Hz, J = 3.9 Hz, 1H), 2.39 (s,
118.0801; found: 118.08250. liquid, b. p.: 170.5 ◦C.
1
5H). 13C { H} NMR (75 MHz CDCl3) d 159.8 (dd, JCF = 271.0,
262.5 Hz), 145.0 (d, JCF = 4.4 Hz), 129.1 (t, JCF = 7.1 Hz), 126.6,
125.1, 88.7 (dd, JCF = 28.3 Hz, 4.4 Hz), 23.82. HRMS (m/z):
calcd for C10H10F2: 168.0848; found: 168.08812. viscous oil.
1-Vinylnaphthalene (Table 2, entry 2). NMR spectra are in
accord to those reported in literature.15 HRMS calcd for C12H10:
154.0804; found: 154.08250. m. p.: 65 ◦C.
1-Ferrocenyl-2,2-difluoroethene (Table 3, entry 4). 1H NMR
(500 MHz, CDCl3) d 5.78 (dd, J = 24.9 Hz, J = 3.9 Hz,
3-Vinylthiophene (Table 2, entry 3). 1H NMR (300 MHz,
1
CDCl3) H NMR (500 MHz, CDCl3) d 7.69 (s, 1H), 7.27 (d,
1
1H), 4.38 (s, 2H), 4.35 (s, 2H), 4.33 (s, 5H). 13C { H} NMR
3J = 7.4 Hz, 2H) 6.55 (dd, J = 16.9, 10.4 Hz, 1H), 4.80 (dd, J =
(125.8 MHz CDCl3) d 160.9 (t, JCF = 215.4 Hz), 86.3 (dd, JCF
=
1
16.9, 1.2 Hz, 1H), 4.59 (dd, J = 17.0, 10.4 Hz, 1H). 13C { H}
19.3, 4.6 Hz), 82.7, 68.2, 67.8, 66.9. HRMS (m/z): calcd for
NMR (75 MHz, CDCl3) d 143.6, 131.8, 129.9, 127.8, 124.2,
115.5. HRMS calcd for C6H6S1: 110.0244; found: 110.02431.
liquid, b. p.: 160 ◦C.
C12H10Fe1F2: 248.0122; found: 248.01301. viscous oil.
1-(1-Naphthyl, 2,2-difluoroethene (Table 3, entry 5). NMR
spectra are in accord to those reported in literature.41 HRMS
(m/z): calcd for C10H8F2: 190.0627; found: 190.06763. viscous
oil.
Vinylferrocene (Table 2, entry 4). 1H NMR (500 MHz,
CDCl3) d 6.52 (dd, J = 16.6, 11.0 Hz, 1H), 4.81 (dd, J = 17.3,
1.2 Hz, 1H), 4.61 (dd, J = 10.2, 1.2 Hz, 1H), 4.18 (s, 2H), 4.12
1
(s, 2H), 4.09 (s, 5H). 13C { H} NMR (125.8 MHz, CDCl3) d
1-(4-Tolyl)-l-chloro-2,2-difluoroethene (Table 4, entry 1).
NMR spectra are in accord to those reported in literature.42
HRMS (m/z): calcd for C9H7Cl1F2: 188.0230; found: 188.02291;
viscous oil.
135.1, 111.4, 83.9, 69.6, 69.1, 67.1. HRMS calcd for C12H12Fe1:
212.0302; found: 212.03082. m. p.: 54 ◦C.
3-Vinylfuran (Table 2, entry 5). 1H NMR (300 MHz, CDCl3)
7.77 (s, 1H), 7.35 (d, 3J = 7.6 Hz, 2H), 6.60 (dd, J = 17.3, 1.3 Hz,
1H), 4.88 (dd, J = 17.3, 1.2 Hz, 1H), 4.67 (dd, J = 11.6, 1.3 Hz,
1-Chloro-1-naphthyl-2,2-difluoroethene (Table 4, entry 2).
NMR spectra are in accord to those reported in literature.43
HRMS (m/z): calcd for C12H7Cl1F2: 224.0283; found:
224.02912. viscous oil.
1
1H). 13C { H} NMR (125.8 MHz, CDCl3) d 145.4, 141.7, 124.7,
122.3, 113.6, 102.7. HRMS (m/z): calcd for C6H6O1: 94.0433;
found: 94.04471. liquid, b. p.: 86 ◦C.
1-(2,6-Dimethylphenyl)-1-chloro-2,2-difluoroethene (Table 4,
2,6-Dimethyl-1-vinylbenzene (Table 2, entry 6). NMR spec-
tra are in accord to those reported in literature.39 HRMS (m/z):
calcd for C10H12: 132.0929; found: 132.08952. liquid, b. p.: 66 ◦C
(10 Torr).
entry 3). 1H NMR (300 MHz, CDCl3) d 7.05–7.02 (m, 1H),
1
6.88 (d, 3J = 7.9 Hz, 2H), 2.21 (s, 6H). 13C { H} NMR (75 MHz
CDCl3) d 161.5 (dd, JCF = 278.2, 267.0 Hz), 137.9, 127.3 (d,
JCF = 4.4 Hz), 125.6 (d, JCF = 3.9 Hz), 93.5, 92.1 (d, JCF
=
2,4-Dimethoxy-3-vinylpyridine (Table 2, entry 7). 1H NMR
4.5 Hz), 18.0. HRMS (m/z): calcd for C10H9Cl1F2: 202.0441;
3
3
(300 MHz, CDCl3) 7.78 (d, J = 8.1 Hz, 1H), 7.34 (d, J =
7.9 Hz, 1H), 6.59 (dd, J = 17.7, 11.0 Hz, 1H), 4.87 (dd, J =
17.6, 1.4 Hz, 1H), 4.68 (dd, J = 11.3, 1.4 Hz, 1H), 3.91 (s, 6H).
found 202.04633; viscous oil.
1-(3-Thiophenyl)-1-chloro-2,2-difluoroethene (Table 4, entry
4). 1H NMR (300 MHz, CDCl3) d 7.3 (dd, 3J = 8.4 Hz,
1
13C { H} NMR (75 MHz, CDCl3) d 163.2, 145.4, 140.9, 132.6,
1
J = 4.1 Hz, 1H), 7.27–7.26 (m, 2H). 13C { H} NMR (75 MHz
106.4, 102.7, 101.1, 53.4. HRMS calcd for C9H11N1O2: 165.0841;
found: 165.08760. m. p.: 121 ◦C.
CDCl3) d 157.4 (dd, JCF = 292.0, 281.8 Hz), 138.3, 132.0 (t, JCF
=
18.1 Hz), 125.2, 122.6, 105.7 (t, JCF = 26.6 Hz). HRMS (m/z):
3-Vinylpyridine (Table 2, entry 8). NMR spectra are in
accord to those reported in literature.40 HRMS calcd for
C7H7N1: 105.0625; found: 105.06390. liquid, m. p.: 126 ◦C.
calcd for C6H3Cl1F2S1: 179.9693; found 179.96753; viscous oil.
1-Phenyl-1-chloro-2,2-difluoroethene (Table 4, entry 5).
NMR spectra are in accord to those reported in literature.44
HRMS (m/z): calcd for C8H5Cl1F2: 174.0026; found 174.00092;
viscous oil.
1-(4-Tolyl)-2,2-difluoroethene (Table 3, entry 1). 1H NMR
3
(300 MHz, CDCl3) d 7.73 (d,3J = 7.1 Hz, 1H), 7.30 (d, J =
1
6.9 Hz, 1H), 6.00 (dd, J = 23.4, 3.7 Hz, 1H), 2.23(s, 3H). 13C { H}
1,1-Diphenyl-2,2-difluoroethene (Table 4, entry 6). NMR
spectra are in accord to those reported in literature.41 HRMS
(m/z): calcd for C14H10F2: 216.0845; found 216.08366. m. p.
177 ◦C.
NMR (75 MHz CDCl3) d 161.0 (dd, JCF = 287.1, 277.0 Hz),
146.3, 131.4, 130.2, 128.3 (t, JCF = 9 Hz), 101.5 (dd, JCF = 29.8,
12.2 Hz), 21.9. HRMS (m/z): calcd for C9H8F2: 154.0611; found:
154.06300. liquid, boiling point: 60 ◦C (12 Torr).
1-(3-Thiophenyl)-2,2-difluoroethene (Table 3, entry 2). 1H
NMR (300 MHz, CDCl3) d 7.73 (d,3J = 7.3 Hz, 1H), 7.31 (d,
1,1-Di(3-thiophenyl)-2,2-difluoroethene (Table 4, entry 7).
NMR spectra are in accord to those reported in literature.38
This journal is
The Royal Society of Chemistry 2010
Green Chem., 2010, 12, 636–642 | 641
©

HRMS (m/z): calcd for C10H6F2S2: 227.9921; found
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227.99159. m. p. 168 ◦C.
1-Phenyl-1-ferrocenyl-2,2-difluoroethene (Table 4, entry 8).
1H NMR (500 MHz, CDCl3) d 7.28–7.22 (m, 5H), 4.57 (s, 2H),
1
4.46 (s, 2H), 4.11 (s, 5H). 13C { H} NMR (125.8 MHz CDCl3)
d 152.4 (dd, JCF = 301.3, 291.5 Hz), 130.6 (d, JCF = 3.1 Hz),
127.6, 127.2 (d, JCF = 2.9 Hz), 126.4 (d, JCF = 2.9 Hz), 91.7 (t,
JCF = 12.0 Hz), 81.3, 73.3, 72.1, 67.6. HRMS (m/z): calcd for
C18H14F2Fe1: 324.0466; found 324.04721. m. p. 146 ◦C.
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28 Skrydstrup et al. (ref. 17) note that deboronation severely complicates
the chromatographic purification of the desired vinylated coupling
products.
1-(3-Pyridyl)-1-ferrocenyl-2,2-difluoroethene (Table 4, entry
9). 1H NMR (500 MHz, CDCl3) d 8.85 (d, 3J = 8.7 Hz, 1H),
8.67 (s, 1H), 7.86–7.84 (m, 1H), 7.41 (d, 3J = 8.3 Hz, 1H) 4.45
1
(s, 2H), 4.29 (s, 2H), 4.03 (s, 5H). 13C { H} NMR (125.8 MHz
CDCl3) d 149.9 (dd, JCF = 267.0, 256.2 Hz), 133.1 (d, JCF
=
1.6 Hz), 131.8 (d, JCF = 1.8 Hz), 130.1, 129.5 (d, JCF = 2.0 Hz),
129.1 (d, JCF = 1.6 Hz), 90.2 (t, JCF = 19.3 Hz), 86.5, 75.7, 74.5,
70.1. HRMS (m/z): calcd for C17H13F2Fe1N1: 325.0401; found
325.04430. m. p. 152–153 ◦C.
29 W. A. Herrmann, A. Salzer, p. 136 in Synthetic Methods of
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Acknowledgements
This work was supported by the DFG and the Fonds der
Chemischen Industrie.
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©