Catalytic C-Se bond formation under very mild conditions for the two-step, one-pot synthesis of aryl selenoacetates

Article abstract of DOI:10.1002/adsc.201200486

Using the palladium/2-(dicyclohexylphosphino)- 2',6'-di(isopropoxy)biphenyl (RuPhos) catalyst, aryl halides and tricyclohexylsilyl selenol can be efficiently coupled to the respective aryl tricyclohexylsilyl selenides. These can be transformed in the same reaction vessel to the corresponding selenoacetates, permitting a straightforward access to a range of molecules potentially useful for materials science applications.

Full text of DOI:10.1002/adsc.201200486

COMMUNICATIONS
DOI: 10.1002/adsc.201200486
À
Catalytic C Se Bond Formation under Very Mild Conditions for
the Two-Step, One-Pot Synthesis of Aryl Selenoacetates
Konstantin Grenader,a Bjçrn Schꢀpbach,a Annabell Peters,a Oliver Kꢀmmel,a
Oliver Halter,a and Andreas Terforta,*
a
Institute for Inorganic Chemistry, University of Frankfurt, Max-von-Laue-Str. 7, 60438 Frankfurt, Germany
Fax : (+49)-69-798-29188; e-mail: aterfort@chemie.uni-frankfurt.de
Received: June 3, 2012; Revised: July 25, 2012; Published online: October 5, 2012
Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/adsc.201200486.
Abstract: Using the palladium/2-(dicyclohexylphos-
phino)-2’,6’-di(isopropoxy)biphenyl (RuPhos) cata-
lyst, aryl halides and tricyclohexylsilyl selenol can
be efficiently coupled to the respective aryl tricyclo-
hexylsilyl selenides. These can be transformed in
the same reaction vessel to the corresponding sele-
noacetates, permitting a straightforward access to
a range of molecules potentially useful for materials
science applications.
together with somewhat different structures.[6] A note-
worthy exception is the hybrid aromatic-aliphatic BPn
system [BPn =CH
structures are similar in the thiolate [BPnS/Au
and the selenolate system [BPnSe/Au(111)], although
3ACHTUNGTRENGU(N C6H4)2ACTHUNGTRENNNUG
(CH2)n], for which the
ACHTUNGTRENNUNG
AHCTUNGTRENNUNG
the long-range order was again better in the latter
one.[9] This similarity was used to reveal a higher
binding energy of Se-AuACTHNUTRGENN(UG 111) vs. the S-AuACHTUNGTRENNUNG(111)
bond by exchange experiments.[10] An interesting con-
troversy is going on regarding the relative conductivi-
ty of the sulphur and selenium atoms when used as
ꢁalligator clipsꢂ for molecule-based electronics.[11]
For these reasons it would be very desirable to
have an efficient and facile access to organoselenium
compounds. For the alkyl selenols typically nucleo-
philic substitution reactions permit a suitable entry.
Keywords: acetylation; aryl halides; nanotechnolo-
gy; silylseleno ethers; silylselenols
Nanotechnology is currently one of the most active While transition metal-catalysed carbon-selenium
fields of scientific research with self-assembling coupling reactions with aryl selenols or their deriva-
mono
SAMs of aromatic thiols on AuCATHNUGTRNEUN(G 111) substrates are the literature, with recently introduced Pd-catalyzed
ACHTUNGTRENNUNG
layers (SAMs) being a distinguished part of it.[1] tives, e.g., aryl diselenides, are already well known in
frequently used in research and development of mo- decarboxylative coupling procedures being especially
lecular electronics inter alia for molecular switches[2] worth mentioning,[12] the synthesis of these important
or memory devices.[3]
building blocks themselves, i.e., the introduction of
The electronic properties of these systems are nega- selenium into the aromatic moiety, to the best of our
tively affected by an often high density of defects,[4] knowledge still requires brute force methods involv-
which has its origins in stress resulting from a misfit ing reactions of corresponding organometallic species
between the lattice preferred by the aromatic moiet- with elementary selenium[6,13] or nucleophilic substitu-
ies and that of the Au
G
tion of aryl halides with alkyl selenolates.[14] These re-
One possible solution for this problem is using a se- actions do not only often require high temperatures,
lenium atom instead of a sulphur one as an anchoring but are in general followed by a tedious work-up ac-
group, since the former seems to experience a lower companied by liberation of highly toxic side-products,
corrugation on the AuACTHNUTRGNEUNG
(111) surface.[6] Already the such as hydrogen selenide or volatile organoselenium
first publication on Se-based SAMs, by Samant compounds, and in many cases result in low overall
et al.[7], reported a dense packing of the molecules in yields. Therefore we were interested to develop an ef-
the form of an incommensurate film. Since then, ficient catalytic one-pot method for the preparation
a number of studies has dealt with the comparison of of aryl selenol derivatives without the disadvantages
thiolate and selenolate SAMs, in particular concern- described above.
ing the order of the systems and the stability of the
Se-Au(111) vs. the S-Au
(111) bond.[8] In most cases, Hartwig,[16] who have obtained several extraordinary
the Se-based systems show superior long-range order results on palladium-catalyzed coupling of aryl halides
Inspired by the work of Soderquist[15] and later
A
ACHTUNGTRENNUNG
Adv. Synth. Catal. 2012, 354, 2653 – 2658
ꢃ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
2653

Konstantin Grenader et al.
COMMUNICATIONS
SAMs on gold,[6] while being less air-sensitive than
the respective selenols or having solubility issues like
the corresponding diselenides.[18] Additionally, aryl se-
lenoacetates have been recently found to be promis-
ing precursors for metal-organic frameworks
(MOFs).[19] Aryl selenoacetates are generally ob-
tained from reacting acetyl chloride (AcCl) with sele-
nols and their derivatives.[18,20]
À
Scheme 1. Preparation of Cy3Si SeH.
To replace the Cy3Si group by the acetyl group, we
treated the reaction mixture obtained with 4-bromo-
biphenyl as starting material first with tetra-n-butyl-
AHCTUNGTRENNGaUN mmonium fluoride (TBAF) in THF, followed by
freshly distilled acetyl chloride. This cleanly converted
the silyl ether to the biphenyl 4-selenoacetate, which
turned out to be isolable by column chromatography
as well as being air and water stable as expected.
Using 4-bromobiphenyl as a model compound, a cata-
lyst screening was conducted, the results of which are
summarised in Table 1.
Scheme 2. Preparation of Cy3Si-protected phenyl selenol.
with triisopropylsilyl thiol (TIPS-SH) as a thiol trans-
In contrast to previously published results on the
fer reagent, we set out to investigate if similar reac- respective reactions with the thiols, the representa-
tions would be possible with a corresponding selenol tives of the JosiPhos family and similar ferrocene-de-
surrogate.
rived ligands showed mostly unsatisfying results. Only
Initial experiments using the analogous selenium CyPF-t-Bu[22] was comparable with the Buchwald-type
reagent, TIPS-SeH, were unsatisfactory since both the ligand RuPhos[21] although the results were by far not
reagent as well as the respective TIPS-protected sele- as superior as those shown by Hartwig et al. for the
nols turned out to be quite sensitive to oxygen and comparable reaction of thiol surrogates.[16] Catalyst
water. We therefore decided to increase the steric hin- loading (Table 1, entries 11–13) experiments have
À
drance around the sensitive Si Se bond by using the shown that the yield gradually decreases with the
previously unknown tricyclohexylsilyl selenol (Cy3Si
SeH), which conveniently can be obtained by reacting
À
amount of catalyst used. Therefore, 5 mol% Pd-
AHCTUNGRTEGNUN(N OAc)2/RuPhos was used for the further optimisation
tricyclohexylsilane with elementary selenium and studies regarding solvent and temperature, the results
turned out to be quite air stable even in solution of which are summarised in Table 2.
(Scheme 1).
While temperature did not appear to have a signifi-
In our preliminary studies, we examined the cou- cant impact on the reaction, with entries 6 to 8 clearly
À
pling of bromobenzene with Cy3Si SeH with 5 mol% demonstrating that elevated temperature is not re-
of Pd
A
zide (LiHMDS) (1.1 equiv.) as base and toluene/dime- vents tested only benzene provided an acceptable
thoxyethane as solvent (Scheme 2). We could observe medium for the current procedure. It remains unclear
full conversion of starting material already at room why the reaction proceeds significantly less satisfacto-
temperature. Due to its facile hydrolysis, the product, rily with toluene.
tricyclohexyl(phenylselanyl)silane, could not be isolat-
Finally, a number of common bases has also been
ed by column chromatography. After several attempts tested (Table 3). Surprisingly we could not obtain the
and optimisations, involving exchange of the solvent desired product even using lithium diisopropylamide
to benzene due to its higher vapour pressure, we were (LDA) which is quite similar in its properties to
able to isolate the coupling product with a still decent LiHMDS, with the reaction resulting in a number of
yield of 53% by gradient sublimation under vacuum by-products. The supreme steric crowding of
directly after work-up.
LiHMDS appears to be essential for a smooth reac-
Nevertheless, the whole procedure turned out to be tion under the given conditions.
too tedious, time consuming, and capricious. Further-
With now optimised conditions in hand, we per-
more, this procedure could not be applied successfully formed a series of reactions utilising a number of aryl
to other substrates, such as 4-bromobiphenyl.
We therefore decided to take a step further and the reaction. The results are summarised in Table 4.
convert the Cy3Si-protected aryl selenols in situ into As can be seen from entries 10 to 12, the reaction
halides as starting material to determine the scope of
the much more stable aryl selenoacetates. The acetate proceeds smoothly with aryl bromides and iodides,
protecting group is of particular interest since aryl se- but only traces of the product can be detected with
lenoacetates can also be directly used to prepare aryl chlorides, while most of the starting material re-
2654
asc.wiley-vch.de
ꢃ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Adv. Synth. Catal. 2012, 354, 2653 – 2658

À
Catalytic C Se Bond Formation under Very Mild Conditions
Table 1. Optimisation of reaction conditions: catalyst screening.[a]
Entry
Precursor
–
Ligand
Loading [mol%]
Conversion [%][b]
Yield [%][c]
1
–
–
0
–
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
Pd
Pd
Pd
Pd
Pd
Pd
N
–
5
0
–
dppe[d]
5e
5
traces
traces
traces
traces
–
n.d.
n.d.
n.d.
n.d.
n.d.
–
74
–
89
75
64
23
74
–
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
55
–
PPh3
–
–
–
5e
5
5
5
5
2.5
5
2.5
1
5
2.5
1
1
1
1
1
1
1
1
1
[d]
G
0
Pd
Pd
Pd
Pd
Pd
Pd
Pd
Pd
Pd
Pd
Pd
Pd
Pd
Pd
Pd
Pd
Pd
Pd
Pd
Pd
SPhos[17]
DavePhos[21]
RuPhos[21]
RuPhos
>99
0
>99
>99
>99
>50
>98
0
<50
traces
traces
<50
traces
<50
traces
>50
traces
traces
>50
traces
RuPhos
Ligand-1[g]
CyPF-t-Bu[22]
SL-J001-1[h]
SL-J002-1[h]
SL-J003-1[h]
SL-J005-1[h]
SL-M001-1[h]
SL-M004-1[h]
SL-W001-1[h]
SL-W002-1[h]
SL-F356-1[h]
SLA101-1 h]
SLA109-1[h]
SL-T001-1[h]
SL-T002-1[h]
1
1
1
1
n.d.
n.d.
50
n.d
[a]
À
Reaction conditions: 4-bromobiphenyl (1 mmol), Cy3Si SeH (1 mmol), LiHMDS (1.1 mmol), precursor/ligand ratio:
1/1 (if not stated otherwise), TBAF (1M in THF, 1.2 mmol), AcCl (5 mmol), and 10 mL benzene as solvent.
Determined typically by GC-MS.
[b]
[c]
[d]
[e]
[f]
Isolated yields.
5 mL of benzene and 5 mL of 1,2-dimethoxyethane used as solvent because of catalyst solubility issues.
10 mol% of ligand used.
Catalyst-1=[5-chloro-2-{(4-chlorophenyl)-[(E)-hydroxyimino]methyl}phenyl-PdCl]2.
Ligand-1=1-(dicyclohexylphosphino)-2-((1-dimethylamino)ethyl)ferrocene.[23]
These ligands are part of a library kindly supplied by Solvias AG (see the Supporting Information for structures).
[g]
[h]
mains unchanged. These findings are supported by under very mild conditions using a Pd-based homoge-
the entries 4 and 5, where only the products deriving neous catalyst system. Surprisingly, the ferrocene-
from the substitution of the bromine atoms could be based ligands (JosiPhos series), which turned out to
À
detected and isolated, thus allowing chemoselective be most successful in related C S bond formation re-
reaction control. No products at all could be obtained actions, do not perform very well for this particular
with substrates containing nitro or enolisable carbonyl reaction, while the biphenyl-derived phosphanes
functional groups (entries 8 and 15) as well as in case (RuPhos and similar) result in very good yields.
of the di
(Boc)imide (entry 16).
Tricyclohexylsilyl selenol turned out to be a suitable
À
In conclusion, we have demonstrated that the C Se and easy to handle Se transfer reagent. The silyl
coupling reaction of aryl bromides can be performed group in the intermediate product can conveniently
Adv. Synth. Catal. 2012, 354, 2653 – 2658
ꢃ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
asc.wiley-vch.de
2655

Konstantin Grenader et al.
COMMUNICATIONS
Table 2. Optimisation of reaction conditions: solvent and temperature screening.[a]
Entry
Solvent
Temperature [8C]
Conversion [%][b]
>99
Yield [%][c]
1
2
3
4
5
6
7
8
dibutyl ether
1,2-dimethoxyethane
chloroform
tetrahydrofuran
toluene
benzene
benzene
benzene
r.t.
r.t.
r.t.
r.t.
r.t.
r.t.
50
56
–
n.d.
–
52
89
83
82
0
traces
0
>99
>99
>99
>99
90
[a]
À
Reaction conditions: 4-bromobiphenyl (1 mmol), Cy3Si SeH (1 mmol), LiHMDS (1.1 mmol), Pd
RuPhos (5 mol%), TBAF (1M in THF, 1.2 mmol), AcCl (5 mmol), and 10 mL solvent.
Determined by GC-MS.
Isolated yields.
(OAc)2 (5 mol%),
[b]
[c]
Table 3. Optimisation of reaction conditions: base screen- ity gradation in the aryl halide series has also been
ACHTUNGTRENNUNG
ing.[a]
demonstrated, showing that aryl chlorides are not
suitable starting materials as yet. Since all reaction
mixtures remained homogeneous it seems unlikely
that insoluble, polymeric metal-chalcogen species or
metallic palladium are involved in the catalytic pro-
cess. Further investigations to improve the efficiency
of the catalytic system (especially in terms of load-
ing), to extend the scope of this reaction as well as to
employ the resulting molecules in nanotechnological
applications are going on in our laboratory and will
be reported separately in due course.
Entry Base
Conversion
[%][b]
Yield
[%][c]
1
2
3
4
5
6
7
LiHMDS
NaHCO3
KO-t-Bu
LDA
triethylamine
diisopropylamine
1,4-diazabicyclo-
>99
89
0
0
0
0
0
0
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
Experimental Section
General Procedure for the Palladium-Catalyzed
Coupling of Aryl Halides with a Selenol Transfer
Reagent
ACHTUNGTRENNUNG
To a solution of 1 mmol of the aryl halide in 4 mL of ben-
zene 1.1 equiv. (1.1 mmol) of the LiHMDS solution (1M in
THF) were slowly added at room temperature under an
argon atmosphere, followed by a solution of 0.05 equiv.
[a]
À
Reaction conditions: 4-bromobiphenyl (1 mmol), Cy3Si
SeH (1 mmol), base (1.1 mmol), Pd(OAc)2 (5 mol%),
ACHTUNGTRENNUNG
RuPhos (5 mol%), TBAF (1M in THF, 1.2 mmol), AcCl
(5 mmol), and 10 mL benzene.
Determined by GC-MS.
(0.05 mmol) PdACHTNUTRGNEUNG(OAc)2 and 0.05 equiv. (0.05 mmol) RuPhos
[b]
[c]
in 1 mL of benzene (stirred for 2 min at room temperature
before addition). The catalyst mixture was degassed by re-
peated short evacuation and flushing of the reaction vessel
with argon. Subsequently a similar degassed solution of
Isolated yields.
be substituted by an acetyl group within the same re-
action flask. The substrate scope includes sterically
crowded reactants, such as 2-bromomesitylene
(Table 4, entry 3), as well as substrates containing car-
À
1 equiv. (1 mmol) of Cy3Si SeH in 5 mL of benzene was
added via septum dropwise within 15 min. The reaction mix-
ture was stirred at room temperature under a slight over-
pressure of argon for 16–20 h. Then 1.2 equiv. (1.2 mmol,
bonyl and carboxylic ester functional groups. Reactiv- 1M in THF) of TBAF, followed by 5 equiv. (5 mmol) of
2656
asc.wiley-vch.de
ꢃ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Adv. Synth. Catal. 2012, 354, 2653 – 2658

À
Catalytic C Se Bond Formation under Very Mild Conditions
Table 4. Scope of the coupling-reaction of aryl halides with
acetyl chloride, were added and the resulting suspension
stirred for further 3 h at room temperature to ensure the
completion of the reaction. Afterwards the reaction mixture
was extracted with ethyl acetate, the organic phase washed
with water and brine, dried over MgSO4, filtered and the
solvent removed under reduced pressure. The crude product
was suspended in dichloromethane with 2.5–3 mass equiv. of
silica gel and stirred for 16–20 h. The solvent was removed
under reduced pressure and the adsorbed product purified
by column chromatography (silica, n-hexane/ethyl acetate
gradient 800/1 to 50/1) followed by gradient sublimation or
bulb-to-bulb distillation under reduced pressure. All prod-
ucts gave satisfactory spectroscopic and analytical data.
a selenol-transfer reagent.[a]
Entry
1
Aryl halide
Yield [%][b]
45
2
3
74
82
Acknowledgements
We thank Dr. B. Pugin of Solvias AG for the generous dona-
tion of the ligand test kit.
4
5
6
7
87
74
83
57
References
[1] a) J. C. Love, L. A. Estroff, J. K. Kriebel, R. G. Nuzzo,
G. M. Whitesides, Chem. Rev. 2005, 105, 1103–1170;
b) C. Vericat, M. E. Vela, G. Benitez, P. Carro, R. C.
Salvarezza, Chem. Soc. Rev. 2010, 39, 1805–1834;
c) S. K. Arya, P. R. Solanki, M. Datta, B. D. Malhotra,
Biosens. Bioelectron. 2009, 24, 2810–2817; d) S. A. Di-
Benedetto, A. Facchetti, M. A. Ratner, T. J. Marks,
Adv. Mater. 2009, 21, 1407–1433.
8
9
–
81
[2] a) J. M. Beebe, J. G. Kushmerick, Appl. Phys. Lett.
2007, 90, 083117–083113; b) K. Seo, A. V. Konchenko,
J. Lee, G. S. Bang, H. Lee, J. Am. Chem. Soc. 2008,
130, 2553–2559; c) A. J. Kronemeijer, H. B. Akkerman,
T. Kudernac, B. J. van Wees, B. L. Feringa, P. W. M.
Blom, B. de Boer, Adv. Mater. 2008, 20, 1467–1473;
d) V. Ferri, M. Elbing, G. Pace, M. D. Dickey, M. Zhar-
nikov, P. Samorꢄ, M. Mayor, M. A. Rampi, Angew.
Chem. 2008, 120, 3455–3457; Angew. Chem. Int. Ed.
2008, 47, 3407–3409; e) N. Crivillers, M. Mas-Torrent, J.
Vidal-Gancedo, J. Veciana, C. Rovira, J. Am. Chem.
Soc. 2008, 130, 5499–5506.
[3] a) M. A. Reed, J. Chen, A. M. Rawlett, D. W. Price,
J. M. Tour, Appl. Phys. Lett. 2001, 78, 3735–3737; b) C.
Li, D. H. Zhang, X. L. Liu, S. Han, T. Tang, C. W.
Zhou, W. Fan, J. Koehne, J. Han, M. Meyyappan, A. M.
Rawlett, D. W. Price, J. M. Tour, Appl. Phys. Lett. 2003,
82, 645–647.
10
11
12
13
traces
89
87
92
14
71
15
16
–
–
17
93
[4] a) D. Kꢅfer, G. Witte, P. Cyganik, A. Terfort, C. Wçll,
J. Am. Chem. Soc. 2006, 128, 1723–1732; b) G. Yang,
G.-y. Liu, J. Phys. Chem. B 2003, 107, 8746–8759;
c) J. F. Kang, A. Ulman, S. Liao, R. Jordan, G. H. Yang,
G. Y. Liu, Langmuir 2001, 17, 95–106; d) L. Duan, S. J.
18
84
[a]
À
Reaction conditions: aryl halide (1 mmol), Cy3Si SeH
Garrett, J. Phys. Chem.
B 2001, 105, 9812–9816;
(1 mmol), LiHMDS (1.1 mmol), Pd
(OAc)2 (5 mol%),
e) T. Y. B. Leung, P. Schwartz, G. Scoles, F. Schreiber,
A. Ulman, Surf. Sci. 2000, 458, 34–52; f) W. Azzam, C.
Fuxen, A. Birkner, H. T. Rong, M. Buck, C. Wçll,
Langmuir 2003, 19, 4958–4968.
RuPhos (5 mol%), TBAF (1M in THF, 1.2 mmol), AcCl
(5 mmol), and 10 mL benzene as solvent.
Isolated yields.
[b]
[5] A. Shaporenko, P. Cyganik, M. Buck, A. Terfort, M.
Zharnikov, J. Phys. Chem. B 2005, 109, 13630–13638.
Adv. Synth. Catal. 2012, 354, 2653 – 2658
ꢃ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
asc.wiley-vch.de
2657

Konstantin Grenader et al.
COMMUNICATIONS
[6] A. Bashir, D. Kꢅfer, J. Mꢀller, C. Wçll, A. Terfort, G.
Witte, Angew. Chem. 2008, 120, 5328–5331; Angew.
Chem. Int. Ed. 2008, 47, 5250–5252.
L. Tꢀrker, Molecules 2005, 10, 1000–1004; c) N. Stuhr-
Hansen, T. I. Solling, L. Henriksen, Tetrahedron 2011,
67, 2633–2643.
[7] M. G. Samant, C. A. Brown, J. G. Gordon, Langmuir
[14] M. Tiecco, L. Testaferri, M. Tingoli, D. Chianelli, M.
Montanucci, J. Org. Chem. 1983, 48, 4289–4296.
[15] A. M. Rane, E. I. Miranda, J. A. Soderquist, Tetrahe-
dron Lett. 1994, 35, 3225–3226.
[16] a) M. A. Fernandez-Rodriguez, Q. L. Shen, J. F. Hart-
wig, J. Am. Chem. Soc. 2006, 128, 2180–2181; b) J. F.
Hartwig, Acc. Chem. Res. 2008, 41, 1534–1544; c) M. A.
Fernandez-Rodriguez, J. F. Hartwig, Chem. Eur. J.
2010, 16, 2355–2359.
[17] a) T. E. Barder, S. D. Walker, J. R. Martinelli, S. L.
Buchwald, J. Am. Chem. Soc. 2005, 127, 4685–4696;
b) A. S. K. Hashmi, A. Loos, S. Doherty, J. G. Knight,
K. J. Robson, F. Rominger, Adv. Synth. Catal. 2011,
353, 749–759.
1992, 8, 1615–1618.
[8] a) F. K. Huang, R. C. Horton, D. C. Myles, R. L. Gar-
rell, Langmuir 1998, 14, 4802–4808; b) C. K. Yee, A.
Ulman, J. D. Ruiz, A. Parikh, H. White, M. Rafailo-
vich, Langmuir 2003, 19, 9450–9458; c) Y. Sato, F. Miz-
utani, Phys. Chem. Chem. Phys. 2004, 6, 1328–1331;
d) T. Weidner, A. Shaporenko, J. Mꢀller, M. Holtig, A.
Terfort, M. Zharnikov, J. Phys. Chem. C 2007, 111,
11627–11635; e) D. Kꢅfer, A. Bashir, G. Witte, J. Phys.
Chem. C 2007, 111, 10546–10551; f) K. Yokota, M. Ta-
niguchi, T. Kawai, J. Am. Chem. Soc. 2007, 129, 5818-
5819.
[9] a) T. Weidner, A. Shaporenko, J. Mꢀller, M. Schmid, P.
Cyganik, A. Terfort, M. Zharnikov, J. Phys. Chem. C
2008, 112, 12495–12506; b) P. Cyganik, K. Szelagowska-
Kunstman, A. Terfort, M. Zharnikov, J. Phys. Chem. C
2008, 112, 15466–15473.
[18] W. A. Reinerth, J. M. Tour, J. Org. Chem. 1998, 63,
2397–2400.
[19] D. L. Turner, K. H. Stone, P. W. Stephens, T. P. Vaid,
Dalton Trans. 2010, 39, 5070–5073.
[10] K. Szelagowska-Kunstman, P. Cyganik, B. Schꢀpbach,
A. Terfort, Phys. Chem. Chem. Phys. 2010, 12, 4400–
4406.
[20] a) S. L. Zhang, Y. M. Zhang, Synth. Commun. 1998, 28,
3999–4002; b) L.-H. Zhou, Y.-M. Zhang, J. Chem. Res.
Synop. 1999, 28–29; c) C. C. Silveira, A. L. Braga, E. L.
Larghi, Organometallics 1999, 18, 5183–5186; d) I. P.
Beletskaya, A. S. Sigeev, A. S. Peregudov, P. V. Petrov-
skii, Russ. J. Org. Chem. 2001, 37, 1703–1709.
[21] a) M. C. Harris, X. H. Huang, S. L. Buchwald, Org.
Lett. 2002, 4, 2885–2888; b) A. Joncour, A. Decor, S.
Thoret, A. Chiaroni, O. Baudoin, Angew. Chem. 2006,
118, 4255–4258; Angew. Chem. Int. Ed. 2006, 45, 4149–
4152; c) G. A. Molander, F. Vargas, Org. Lett. 2007, 9,
203–206; d) R. Martin, S. L. Buchwald, Acc. Chem. Res.
2008, 41, 1461–1473; e) D. S. Surry, S. L. Buchwald,
Angew. Chem. 2008, 120, 6438–6461; Angew. Chem. Int.
Ed. 2008, 47, 6338–6361; f) D. S. Surry, S. L. Buchwald,
Chem. Sci. 2011, 2, 27–50.
[22] Q. L. Shen, S. Shekhar, J. P. Stambuli, J. F. Hartwig,
Angew. Chem. 2005, 117, 1395–1399; Angew. Chem.
Int. Ed. 2005, 44, 1371–1375.
[23] a) T. J. Kim, Y. H. Kim, H. S. Kim, S. C. Shim, Y. W.
Kwak, J. S. Cha, H. S. Lee, J. K. Uhm, S. I. Byun, Bull.
Korean Chem. Soc. 1992, 13, 588–592; b) A. Herrbach,
A. Marinetti, O. Baudoin, D. Guenard, F. Gueritte, J.
Org. Chem. 2003, 68, 4897–4905.
[11] a) J. M. Seminario, A. G. Zacarias, J. M. Tour, J. Am.
Chem. Soc. 1999, 121, 411–416; b) S. N. Yaliraki, M.
Kemp, M. A. Ratner, J. Am. Chem. Soc. 1999, 121,
3428–3434; c) J. M. Tour, W. A. Reinerth, L. Jones, T. P.
Burgin, C. W. Zhou, C. J. Mꢀller, M. R. Deshpande,
M. A. Reed, in: Molecular Electronics: Science and
Technology, Vol. 852, (Eds.: A. Aviram, M. Ratner),
New York Academy of Sciences, New York, 1998,
pp 197–204; d) L. Patrone, S. Palacin, J. P. Bourgoin, J.
Lagoute, T. Zambelli, S. Gauthier, Chem. Phys. 2002,
281, 325–332; e) L. Patrone, S. Palacin, J. P. Bourgoin,
Appl. Surf. Sci. 2003, 212, 446–451.
[12] a) I. P. Beletskaya, V. P. Ananikov, Chem. Rev. 2011,
111, 1596–1636; b) Z. Duan, S. Ranjit, P. Zhang, X.
Liu, Chemistry 2009, 15, 3666–3669; c) S. Ranjit, Z.
Duan, P. Zhang, X. Liu, Org. Lett. 2010, 12, 4134–4136;
d) J.-M. Becht, C. Le Drian, J. Org. Chem. 2011, 76,
6327–6330; e) R. Shang, L. Liu, Sci. China Chem. 2011,
54, 1670–1687.
[13] a) M. Clarembeau, A. Cravador, W. Dumont, L.
Hevesi, A. Krief, J. Lucchetti, D. Vanende, Tetrahedron
1985, 41, 4793–4812; b) S. Yavuz, A. Dis¸li, Y. Yıldırır,
2658
asc.wiley-vch.de
ꢃ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Adv. Synth. Catal. 2012, 354, 2653 – 2658