Iron-catalyzed ligand-free carbon-selenium (or tellurium) coupling of arylboronie acids with diselenides and ditellurides

Article abstract of DOI:10.1002/adsc.200900095

Carbon-selenium and carbon-tellurium cross-couplings of arylboronie acids with diselenides and ditellurides have been catalyzed by iron(0), iron(II) chloride or iron(III) chloride without any ligand and additive in the air. The method yields the corresponding unsymmetrical diorgano monoselenides and monotellurides in good to excellent yields, displays a broad substrate scope, and is simple, convenient, effective, economical and environmentally friendly.

Full text of DOI:10.1002/adsc.200900095

FULL PAPERS
DOI: 10.1002/adsc.200900095
Iron-Catalyzed Ligand-Free Carbon-Selenium (or Tellurium)
Coupling of Arylboronic Acids with Diselenides and Ditellurides
Min Wang,a Kai Ren,a and Lei Wanga,b,*
a
Department of Chemistry, Huaibei Coal Teachers College, Huaibei, Anhui 235000, Peopleꢀs Republic of China
Fax : (+86)-561-3090-518; phone: (+86)-561-3802-069; e-mail: leiwang@hbcnc.edu.cn
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of
b
Sciences, Shanghai 200032, Peopleꢀs Republic of China
Received: February 11, 2009; Revised: April 20, 2009; Published online: June 18, 2009
Abstract: Carbon-selenium and carbon-tellurium displays a broad substrate scope, and is simple, con-
cross-couplings of arylboronic acids with diselenides venient, effective, economical and environmentally
and ditellurides have been catalyzed by iron(0), friendly.
iron(II) chloride or iron
ACHTUNGERTN(NUNG III) chloride without any
ligand and additive in the air. The method yields the
corresponding unsymmetrical diorgano monosele- Keywords: arylboronic acids; C Se (Te) cross-cou-
nides and monotellurides in good to excellent yields, pling; diselenides; ditellurides; iron
À
Introduction
for the generation of the corresponding anion[11] or
metal-monochalcogenide complex.[12]
Organic chalcogens, especially selenium and tellurium
Organoboronic acids are widely used as reagents in
as structural motifs, are commonly found in a variety organic synthesis because they are commercially
of molecules of interest to biological, pharmaceuti- available, stable, generally non-toxic, and compatible
cal[1] and material sciences.[2] To synthesize these com- with a variety of functional groups. Recently, a
À
pounds, various procedures have been explored so copper-catalyzed C Se (Te) coupling reaction of aryl-
far.[3] The commonly used method to introduce a sele- boronic acids with diselenides and ditelluride has
nium or tellurium moiety into organic molecules is been demonstrated by our group.[13] After that, the
the reaction of a metal selenolate or tellurolate with synthesis of unsymmetrical monochalcogenides, in-
appropriate electrophiles, such as organic halides, acyl cluding sulfides, selenides, and tellurides from dichal-
chlorides, epoxides, and a,b-enones.[4] However, it is cogenides with organoboronic acids in the presence of
more difficult to synthesize the unsymmetrical diorga- CuI and the ligand 2,2’-dipyridyl was described.[14]
no monoselenides and monotellurides through the re-
Over the past few years, iron salts as effective, al-
action of selenide and telluride anions with aryl hal- ternative and promising transition metal catalysts
2
À
ides because of the lower reactivity of C
bonds.
G
Transition metal-catalyzed aryl carbon-chalcogen benign properties. Since the pioneering research work
bond formation is one of the important methods for of Tamura and Kochi,[15] iron-catalyzed oxidation,[16]
the preparation of unsymmetrical organochalcoge- hydrogenation,[17] hydrosilylation,[18] rearrangement,[19]
nides.[5] For the preparation of aryl chalcogenides, Michael addition,[20] and C C bond forming reactions
À
C S and C Se coupling reactions of aryl halides with have been intensively investigated.[21–23] Most recently,
À
À
À
thiols and selenols have been successfully carried out the iron-catalyzed S-arylation of thiols (C S bond for-
in the presence of palladium,[6] nickel,[7] or copper as mation),[24] N-arylation of nitrogen nucleophiles (C N
À
catalyst[8] under basic reaction conditions. On the bond formation),[25] and O-arylation of phenols (C O
À
other hand, dichalcogenides are used as substrates in bond formation)[26] with aryl halides have been devel-
the synthesis of diorgano monoselenides and monotel- oped. Because of the interest for both the academic
lurides since they are stable compounds in air and are as well as the industrial community, it is desirable to
easy to handle. However, the method is limited to expand the application scope of iron catalysts in or-
alkyl halides.[9,10] Meanwhile, in the metal-catalyzed ganic transformations due to their unique and signifi-
chalcogenylation of aryl halides with dichalcogenide cant advantages. As part of our ongoing efforts devot-
used as reactant, an efficient reductant is necessary ed to the synthesis of unsymmetrical organochalcoge-
1586
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Iron-Catalyzed Ligand-Free Carbon-Selenium (or Tellurium) Coupling of Arylboronic Acids
FULL PAPERS
desired products were obtained respectively when
10 mol% of FeCl2 and Fe(0) powder were used as cat-
alyst for the model reaction (Table 1, entries 5 and 6).
However, when Fe2ACTHUNGTRNENGU(SO4)3, FeACHTUNTGRNE(NUGN acac)3, Fe2O3 or
Fe(OH)3 was used as catalyst, no trace of the desired
product was isolated and the starting materials were
recovered (Table 1, entries 7–10). Microwave irradia-
tion (MWI) conditions could significantly shorten the
Scheme 1.
nides, herein we wish to report the first genuinely and reaction time from 20 h to 0.5 h, but the yield of the
highly efficient ligand-free iron-catalyzed preparation desired product was reduced from 91% to 69%
of unsymmetrical diorgano monoselenides and mono- (Table 1, entry 1).
tellurides from arylboronic acids with diselenides and
ditellurides through the direct C Se and C Te cross- model reaction using 10 mol% of Fe(0) powder as
coupling reactions (Scheme 1).
Next, different solvents were examined for the
À
À
catalyst at 1308C, and the results are summarized in
Table 2. Noteworthy is that the choice of DMSO as
the solvent was crucial, and 97% yield of the desired
product was provided (Table 2, entry 1). Indeed, when
another solvent, such as DMA, toluene, xylene, ben-
Results and Discussion
For initial optimization of the reaction conditions, di- zene, CH3OH, C2H5OH, or CH3CN was used instead
phenyl diselenide and p-methoxyphenylboronic acid of DMSO, the desired coupling products were ob-
were chosen as model substrates. As shown in tained in lower yields (Table 2, entries 2–8). Unfortu-
Table 1, we screened a wide range of iron sources as nately, no desired product was isolated when the reac-
catalyst in DMSO at 1308C and found that the cross- tion was carried out in N,N-dimethylformamide
coupling reaction proceeded smoothly and generated (DMF), or 1,4-dioxane (Table 2, entries 9 and 10).
the desired product p-methoxypheny phenyl selenide
in 91% yield, representing one of the best results
when 10 mol% of FeCl3 was used as catalyst without
any ligand and additive in an air atmosphere (Table 1,
À
Table 2. Effect of solvent and ligand on the C Se cross-cou-
pling reaction.[a]
entry 1). Other iron sources, such as FeCl3·6H2O,
FeACHTUNGTRENNUNG(NO3)3·9H2O, and FeACHTUGNTRENN(GUN SO4)2·7H2O were inferior
Entry
Solvent/Temp. [8C]
Ligand
Yield[b] [%]
and generated p-methoxyphenyl phenyl selenide in
88, 43, and 25% yields, respectively (Table 1, en-
tries 2–4). To our delight, 94 and 97% yields of the
1
2
3
4
5
6
7
8
DMSO/130
DMA/130
none
none
none
none
none
none
none
none
none
none
DMEDA
Phen
97
61
56
21
19
42
53
36
0
Toluene/130
Xylene/130
Benzene/80
CH3OH/68
C2H5OH/78
CH3CN/82
DMF/130
Dioxane/100
DMSO/130
DMSO/130
DMSO/130
DMSO/130
DMSO/130
DMSO/130
À
Table 1. Effect of iron source on the C Se cross-coupling re-
action.[a]
9
Entry
Iron Source
Yield[b] [%]
10
11
12
13
14[c]
15[d]
16[e]
0
1
2
3
4
5
FeCl3
FeCl3·6H2O
91; 69[c]
87
90
91
97
72
98
88
43
25
94
97
0
FeN
ACHTNUGTERN(NGNU C6H5)3P
Fe(SO4)2·7H2O
E
DPPF
none
none
FeCl2
Fe powder
6
7
Fe2ACHTNUTGREN(UNG SO4)3
[a]
Reaction conditions: p-methoxyphenylboronic acids
(1.1 equiv.), diphenyl diselenide (0.5 equiv.), Fe powder
(0.1 equiv.), ligand (0.1 equiv., if necessary), solvent
(1.0 mLmmolÀ1) at the temperature indicated in Table 2,
8
FeN(acac)3
0
9
Fe2O3
0
10
Fe(OH)3
0
[a]
Reaction conditions: p-methoxyphenylboronic acids
(1.1 equiv.), diphenyl diselenide (0.5 equiv.), Fe source
(0.1 equiv.), DMSO (1.0 mLmmolÀ1), 1308C, 20 h.
Isolated yields.
A commercially available Sale WP 650, 650-watt micro-
wave oven was utilized at 2450 MHz at 100% power for
0.5 h.
20 h.
Phen=1,10-phenanthroline, DMEDA=N,N’-dimethyl-
AHCTUNGTREGeNNNU thylenediamine.
Isolated yields.
For 8 h.
DPPF=1,1’-bis(diphenylphosphino)ferrocene,
[b]
[c]
[b]
[c]
[d]
[e]
In the presence of Fe (0.05 equiv.).
In the presence of Fe (0.20 equiv.).
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[a]
À
À
Table 3. Fe-catalyzed direct C Se and C Te cross-coupling reactions.
Entry
G
R2B(OH)2
R1YR2
Yield[b] [%]
1
2
3
4
5
6
7
8
N
4-MeOC6H4B(OH)2
2-MeOC6H4B(OH)2
3-MeOC6H4B(OH)2
2,4-(MeO)2C6H3B(OH)2
2,6-(MeO)2C6H3B(OH)2
4-MeSC6H4B(OH)2
4-MeO2CC6H4B(OH)2
2-OHCC6H4B(OH)2
C6H5B(OH)2
4-MeOC6H4SeC6H5
2-MeOC6H4SeC6H5
3-MeOC6H4SeC6H5
2,4-(MeO)2C6H3SeC6H5
2,6-(MeO)2C6H3SeC6H5
4-MeSC6H4SeC6H5
4-MeO2CC6H4SeC6H5
2-OHCC6H4SeC6H5
4-MeOC6H4SeC6H5
97
90
79
96
78
95
96
66
88
78
62
91
90
80
86
97
0
62
77
98
90
94
88
86
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
4-ClC6H4B(OH)2
4-BrC6H4B(OH)2
4-FC6H4B(OH)2
4-MeOC6H4SeC6H
4-MeOC6H4SeC6H
4-MeOC6H4SeC6H
4-MeOC6H4SeC6H
4-MeOC6H4SeC6H
4-MeOC6H4SeC6H
4-MeOC6H4SeC6H
4A
4A(4-Br)
4A(4-F)
4A(4-Me)
4A(3-Me)
4A(2-Me)
4A(4-t-C4H9)
2A(CH2)2CH3
(4-MeO)
CHTUNGTRENNUNG
CHTUNGTRENNUNG
CHTUNGTRENNUNG
CTHUNGTRENNUNG
CTHUNGTRENNUNG
G
4-MeC6H4B(OH)2
3-MeC6H4B(OH)2
2-MeC6H4B(OH)2
4-t-C4H9C6H4B(OH)2
n-C4H9B(OH)2
4-MeOC6H4B(OH)2
4-MeOC6H4B(OH)2
4-MeOC6H4B(OH)2
3-MeOC6H4B(OH)2
2-MeOC6H4B(OH)2
4-MeO2CC6H4B(OH)2
C6H5B(OH)2
4-MeOC6H4SeCH
n-C4H9SeC6H4A
CHTUNGTRENNUNG
G
4-MeOC6H4SeCH2C6H5
4-MeOC6H4TeC6H5
3-MeOC6H4TeC6H5
2-MeOC6H4TeC6H5
4-MeO2CC6H4TeC6H5
4-MeOC6H4TeC6H5
[a]
Reaction conditions: arylboronic acids (1.1 mmol), dichalcogenide (0.5 mmol), Fe (0.1 mmol), DMSO (1.0 mL), 1308C,
20 h.
Isolated yield.
[b]
Meanwhile, we also investigated the influence of was evaluated. The results are listed in Table 3. At
the ligand on the model reaction. The result showed the beginning of the experiments to probe the sub-
that the yield of desired cross-coupling product was strate scope for the boronic acids, when diphenyl dise-
slightly decreased when DMEDA, Phen, or Ph3P as lenide or di(p-methoxyphenyl) diselenide was taken
ligand was added to the reaction system (Table 2, en- as dichalcogenide partner, a variety of electron-rich,
tries 11–13). When DPPF (10 mol%) as ligand was electron-neutral, and electron-deficient arylboronic
À
À
added to the reaction, C Se coupling of the model acids underwent the C Se cross-coupling reactions
substrates was smoothly accomplished within 8 h and smoothly to generate the corresponding diaryl mono-
afforded the desired monoselenide in 97% yield selenides in good to excellent yields (Table 3, en-
(Table 2, entry 14). With respect to the catalyst load- tries 1–16). Furthermore, sterically demanding ortho
ing, 10 mol% of Fe was found to be optimal. When substituents did not hamper the cross-coupling reac-
only 5 mol% of Fe was used, the desired product was tion and the corresponding unsymmetrical diaryl
isolated in 72% yield (Table 2, entry 15), and no sig- monoselenides were obtained in good yields (Table 3,
nificant improvement was observed with 20 mol% of entries 2, 4, 5, 8 and 15). A more remarkable observa-
Fe (Table 2, entry 16). During the course of our fur- tion was that the extremely sterically hindered 2,6-di-
ther optimization of the reaction conditions, the reac- methoxyphenylboronic acid reacted with diphenyl di-
tion was generally completed within 20 h at 1308C in
ACHTUNGTRENsNGNU elenide under these reaction conditions to generate
DMSO by using 10 mol% of Fe without an additional the desired product in 78% isolated yield (Table 3,
P ligand DPPF in consideration of environmental entry 5). What’s more, the tolerance of potentially re-
friendliness and low cost.
active functional groups, such as carbonyl and ester
On the basis of the previously optimized reaction groups, to the described protocol is remarkable
conditions, the scope of this transformation in the (Table 3, entries 7 and 8). However, no desired prod-
direct cross-coupling reaction of a variety of dichalco- uct was isolated when an alkylboronic acid, such as n-
genides with differently substituted arylboronic acids C4H9B(OH)2 was used as substrate (Table 3,
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Iron-Catalyzed Ligand-Free Carbon-Selenium (or Tellurium) Coupling of Arylboronic Acids
FULL PAPERS
Scheme 2.
entry 17). Fortunately, dialkyl diselenides, such as n- arylboronic acids met with failure, probably due to
À
C4H9SeSeC4H9-n,
and
dibenzyl
diselenide the stronger S S bond, and starting materials were re-
C6H5CH2SeSeCH2C6H5, also reacted with p-methoxy- covered unconsumed.
phenylboronic acid to form the corresponding prod-
To investigate the reaction mechanism, a reaction
ucts in 62 and 77% yields, respectively (Table 3, en- of (C6H5Se)2 and 4-MeOC6H4B(OH)2 was examined
tries 18 and 19).
initially in the absence of oxygen. When the FeCl2- or
As an alternative to organoboronic acids and esters, FeCl3-catalyzed the reaction was carried out, only a
organotrifluoroborate salts have emerged as a new trace amount of desired cross-coupling product was
class of air-stable boron derivatives, facile to prepare isolated. When Fe(0) powder was used as catalyst, a
in high yields and purities, easy to handle, and feasi- 94% yield of desired product was obtained.
ble to utilize in a number of useful synthetic process-
Also, an iron-promoted reaction of (C6H5Se)2 and
es.[27] When the reactions of potassium p-methoxyphe- n-C6H13Br was examined. When the reaction was car-
nyltrifluoroborate with diphenyl diselenide and di- ried out in the presence of catalytic amount of FeCl2,
phenyl diselenide were performed under the present FeCl3, or Fe(0) (10 mol%), no desired product was
reaction conditions, as expected, 90% and 93% yields isolated in the absence of oxygen or in the presence
of the desired products were isolated (Scheme 2).
of oxygen. As expected, a 90% yield of n-
Then, we explored the cross-coupling reaction using C6H13SeC6H5 was obtained under an inert atmosphere
other dichalcogenides, such as ditellurides and disul- when 1.2 equiv. of Fe(0) were used, indicating forma-
fides. The cross-coupling of diphenyl ditelluride or tion of the [C6H5Se]À anion.
di(p-methoxyphenyl) ditelluride with a number of
A possible mechanism for the Fe(0)-catalyzed reac-
substituted arylboronic acids under the present reac- tion is shown in Scheme 3. In cycle A, after
À
tion conditions also occurred with C Te bond forma- PhSeFe(II)SePh was formed from (PhSe)2 and Fe(0)
tion smoothly to afford the desired diaryl monotellur- via an oxidative addition, ArB(OH)2 reacted with
ides in good yields, which were not affected by the PhSeFe(II)SePh via transmetallation to form
nature or steric hindrance of substituted groups on PhSeFe(II)Ar, which produced the coupling product
the benzene ring in the arylboronic acids (Table 2, en- PhSeAr and regenerated Fe(0). In cycle B, after the
tries 20–24). However, all attempts to use diaryl disul- reaction of ArB(OH)2 and Fe(0), ArFe(II)B(OH)2
À
fides as chalcogen source for direct C S coupling with was produced, which reacted with “ACTHNUTRGNEUNG
[PhSe]À”, another
Scheme 3. Possible mechanism for the reaction.
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Min Wang et al.
FULL PAPERS
half of (PhSe)2 to form PhSeFe(II)Ar, indicating the General Procedure for Iron-Catalyzed Preparation of
molar ratio of (PhSe)2 and ArB(OH)2 (1:2). Monochalcogenides from Dichalcogenides with
From these results we observed that FeCl3 and Arylboronic Acids without Any Ligand and Additive
FeCl2 have a comparable catalytic activity in the reac-
tion. For the FeCl3-catalyzed reaction, the precatalyst A 10-mL reaction tube was charged with dichalcoge-
Fe
Similarly, in cycle A’, after PhSeFe
obtained from (PhSe)2 and Fe(II) via an oxidation ad- tion vessel was placed in an oil bath at 1308C. After
dition, ArB(OH)2 reacted with PhSeFe(III)(Cl)SePh the reaction had been carried out at this temperature
via a transmetallation to form PhSeFe(III)(Cl)Ar, for 20 h, it was cooled to room temperature, diluted
ACHTUNGTRENNUNG
AHCTUNGTRENNUNG
AHCTUNGTRENNUNG
AHCTUNGTRENNUNG
which generated PhSeAr as product via a reductive with H2O and extracted twice with Et2O. The organic
elimination and regenerated Fe(II) in the presence of layers were combined, dried over Na2SO4, and con-
oxygen.
centrated to yield the crude product, which was fur-
ther purified by flash chromatography on silica gel
(eluant: petroleum ether) to give the desired cross-
coupling product.
Conclusions
In summary, we have successfully developed novel,
economical, environmentally friendly, and practical General Procedure for Iron-Catalyzed Preparation of
À
À
iron-catalyzed ligand-free direct C Se and C Te Monochalcogenides from Dichalcogenides with
cross-couplings of arylboronic acids with diselenides Arylboronic Acids in the Presence of DPPF
and ditellurides. The reactions were carried out in the
presence of catalytic amounts of iron in DMSO with- A 10-mL reaction tube was charged with dichalcoge-
out any ligand and additive. This method provides the nide (0.5 mmol), arylboronic acid (1.1 mmol), Fe(0)
desired unsymmetrical diorgano monoselenides and powder (0.1 mmol), DPPF (0.1 mmol) and DMSO
monotellurides in good to excellent yields in most (1.0 mL). The reaction vessel was placed in an oil
cases. Overall, the novel iron-catalyzed protocol re- bath at 1308C. After the reaction had been carried
ported here constitutes a promising carbon-chalcogen out at this temperature for 8 h, it was cooled to room
bond-forming process of potential industrial signifi- temperature, diluted with H2O and extracted twice
cance because of its operational simplicity and envi- with Et2O. The organic layers were combined, dried
ronmental and economic advantages, it also expands over Na2SO4, and concentrated to yield the crude
the application scope of iron catalysts as a versatile product, which was further purified by flash chroma-
tool in organic synthesis. Studies on its increased effi- tography on silica gel (eluant: petroleum ether) to
ciency and enlargement of the substrate scope and give the desired cross-coupling product.
further investigations on the application of this kind
of catalyst in asymmetric catalysis are in progress.
Spectral data of the monochalcogenides prepared
are listed below.
Experimental Section
4-Methoxyphenyl Phenyl Selenide[14]
General Remarks
All reactions were carried out under an air atmos-
phere. All reagents were purchased from commercial 1H NMR (400 MHz, CDCl3): d=7.50 (d, J=8.8 Hz,
suppliers and used after further purification. Products 2H), 7.33–7.31 (m, 2H), 7.21–7.16 (m, 3H), 6.84 (d,
were purified by flash chromatography on 230–400 J=8.4 Hz, 2H), 3.79 (s, 3H); 13C NMR (100 MHz,
1
mesh silica gel, SiO2. All H NMR, 13C NMR spectra CDCl3): d=159.7, 136.5, 133.2, 130.9, 129.1, 126.4,
were measured on a Bruker Avance NMR spectrome- 119.9, 115.1, 55.2.
ter (400 MHz or 100 MHz, respectively) with CDCl3
as solvent and recorded in ppm relative to tetrame-
thylsilane as internal standard. High resolution mass 3-Methoxyphenyl Phenyl Selenide[28]
spectroscopy data of the products were collected on a
Waters Micromass GCT instrument.
1H NMR (400 MHz, CDCl3): d=7.49–7.48 (m, 2H),
7.26–7.25 (m, 3H), 7.18–7.14 (m, 1H), 7.03–7.00 (m,
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Iron-Catalyzed Ligand-Free Carbon-Selenium (or Tellurium) Coupling of Arylboronic Acids
FULL PAPERS
4-Methoxycarbonylphenyl Phenyl Selenide[14]
2H), 6.78 (d, J=8.0 Hz, 1H), 3.72 (s, 3H); 13C NMR
(100 MHz, CDCl3): d=159.9, 133.2, 132.2, 130.7,
130.0, 129.3, 127.4, 124.9, 117.9, 113.0, 55.2
1H NMR (400 MHz, CDCl3): d=7.86 (d, J=8.4 Hz,
2H), 7.58 (q, J=2.0, 6.0 Hz, 2H), 7.37–7.34 (m, 5H),
3.89 (s, 3H); 13C NMR (100 MHz, CDCl3): d=166.8,
139.7, 135.0, 1302.3, 130.2, 129.7, 128.7, 128.5, 128.2,
52.1.
2-Methoxyphenyl Phenyl Selenide[14]
1H NMR (400 MHz, CDCl3): d=7.58–7.56 (m, 2H),
7.33–7.30 (m, 3H), 7.20–7.15 (m, 1H), 6.94 (q, J=1.6,
6.0 Hz, 1H), 6.84 (q, J=1.2, 7.2 Hz, 1H), 6.80–6.76
(m, 1H), 3.87 (s, 3H); 13C NMR (100 MHz, CDCl3):
d=156.6, 135.5, 130.8, 129.5, 128.3, 128.1, 127.7, 121.9,
121.6, 110.4, 55.9.
2-Formylphenyl Phenyl Delenide[30]
1H NMR (400 MHz, CDCl3): d=10.1 (s, 1H), 7.78–
7.76 (m, 1H), 7.61–7.59 (m, 2H), 7.41–7.34 (m, 3H),
7.27–7.20 (m, 2H), 6.98 (d, J=7.2 Hz, 1H); 13C NMR
(100 MHz, CDCl3): d=192.6, 139.6, 136.8, 135.1,
133.9, 133.7, 129.9, 129.1, 128.1, 125.5.
2,4-Dimethoxyphenyl Phenyl Selenide[29]
4-Chlorophenyl 4’-Methoxyphenyl Selenide
1H NMR (400 MHz, CDCl3): d=7.42–7.39 (m, 2H),
7.25–7.22 (m, 4H), 6.50 (d, J=2.4 Hz, 1H), 6.43 (q,
J=2.4, 6.0 Hz, 1H), 3.83 (s, 3H), 3.80 (s, 3H);
13C NMR (100 MHz, CDCl3): d=161.3, 159.2, 135.3,
132.4, 129.1, 126.8, 110.3, 105.7, 99.0, 56.0, 55.5.
1H NMR (400 MHz, CDCl3): d=7.45 (d, J=8.8 Hz,
2H), 7.19 (d, J=8.8 Hz, 2H), 7.12 (d, J=8.8 Hz, 2H),
6.82 (d, J=8.8 Hz, 2H), 3.77 (s, 3H); 13C NMR
(100 MHz, CDCl3): d=160.0, 136.7, 132.5, 132.1,
131.6, 129.3, 119.5, 115.3, 55.3; HR-MS (ESI): m/z=
297.9670 ([M]+), calcd. for C13H11ClO80Se: 297.9664;
m/z=295.9667, calcd. for C13H11ClO78Se: 295.9671.
2,6-Dimethoxyphenyl Phenyl Selenide[13]
4-Bromophenyl 4’-Methoxyphenyl Selenide
1H NMR (400 MHz, CDCl3): d=7.41–7.38 (m, 2H),
7.24–7.19 (m, 4H), 6.49 (d, J=2.4 Hz, 1H), 6.41 (q,
J=2.4, 6.0 Hz, 1H), 3.81 (s, 3H), 3.78 (s, 3H);
13C NMR (100 MHz, CDCl3): d=161.2, 159.1, 135.2,
132.3, 131.0, 129.1, 126.8, 110.2, 105.6, 98.9, 55.9, 55.4. 1H NMR (400 MHz, CDCl3): d=7.49 (d, J=8.8 Hz,
2H), 7.31 (d, J=8.4 Hz, 2H), 7.15 (d, J=8.4 Hz, 2H),
6.86 (d, J=8.4 Hz, 2H), 3.81 (s, 3H); 13C NMR
(100 MHz, CDCl3): d=160.0, 136.7, 132.5, 132.1,
4-Methylthiophenyl Phenyl Selenide
131.6, 129.3, 119.5, 115.3, 55.3; HR-MS (ESI): m/z=
341.9157 ([M]+), calcd. for C13H11BrO80Se: 341.9158.
1H NMR (400 MHz, CDCl3): d=7.39 (d, J=8.4 Hz,
4H), 7.23–7.21 (m, 3H), 7.12 (d, J=8.4 Hz, 2H), 2.43
(s, 3H); 13C NMR (100 MHz, CDCl3): d=138.4, 134.0,
132.2, 131.6, 129.2, 127.1, 127.0, 126.6, 15.5; HR-MS
4-Flurophenyl 4’-Methoxyphenyl Selenide[31]
(ESI): m/z=276.9858 ([M]+), calcd. for C13H12S77Se: 1H NMR (400 MHz, CDCl3): d=7.45 (d, J=8.8 Hz,
276.9859.
2H), 7.34 (q, J=5.4, 4.8 Hz, 2H), 6.91 (t, J=8.8 Hz,
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2H), 6.83 (d, J=8.8 Hz, 2H), 3.81 (s, 3H); 13C NMR CDCl3): d=159.6, 149.7, 136.1, 131.0, 129.2, 126.2,
(100 MHz, CDCl3): d=163.2, 160.8, 159.7, 135.8, 120.4, 115.0, 55.2, 34.4, 31.2; HR-MS (ESI): m/z=
133.5, 133.4, 127.2, 120.5, 116.3, 116.1, 115.1, 55.2.
320.0677 ([M]+), calcd. for C17H20O80Se: 320.0679;
m/z=318.0680, calcd. for C17H20O78Se: 318.0687.
4-Methylphenyl 4’-Methoxyphenyl Selenide
n-Butyl 4-Methoxyphenyl Selenide[13]
1H NMR (400 MHz, CDCl3): d=7.45 (d, J=8.8 Hz,
2H), 7.27 (q, J=8.0 Hz, 2H), 7.03 (t, J=8.0 Hz, 2H), 1H NMR (400 MHz, CDCl3): d=7.48 (d, J=8.8 Hz,
6.81 (d, J=8.8 Hz, 2H), 3.77 (s, 3H), 2.28 (s, 3H); 2H), 6.83 (d, J=8.8 Hz, 2H), 3.80 (s, 3H), 2.83 (t, J=
13C NMR (100 MHz, CDCl3): d=159.5, 136.7, 135.8, 7.6 Hz, 2H), 1.67–1.63 (m, 2H), 1.44–1.39 (m, 2H),
131.8, 130.0, 129.0, 120.9, 115.1, 55.3, 21.1: HR-MS 0.91 (t, J=7.6 Hz, 3H); 13C NMR (100 MHz, CDCl3):
(ESI): m/z=278.0211 ([M]+), calcd. for C14H14O80Se: d=159.1, 135.5, 120.2, 114.7, 55.3, 32.3, 28.8, 22.9,
278.0210; m/z=276.0223, calcd. for C14H14O78Se: 13.6.
276.0218.
4-Methoxyphenyl Phenyl Telluride[14]
3-Methylphenyl 4’-Methoxyphenyl Selenide
1H NMR (400 MHz, CDCl3): d=7.72 (d, J=8.8 Hz,
2H), 7.55 (q, J=2.8, 4.0 Hz, 2H), 7.20–7.13 (m, 3H),
1H NMR (400 MHz, CDCl3): d=7.47 (d, J=8.4 Hz, 6.78 (d, J=8.8 Hz, 2H), 3.78 (s, 3H); 13C NMR
2H), 7.16 (s, 1H), 7.11–7.04 (m, 2H), 6.96 (d, J= (100 MHz, CDCl3): d=160.0, 141.2, 136.4, 129.4,
7.2 Hz, 1H), 6.81 (d, J=8.8 Hz, 2H), 3.75 (s, 3H), 127.3, 115.9, 115.6, 103.2, 55.2.
2.24 (s, 3H); 13C NMR (100 MHz, CDCl3): d=159.6,
138.8, 136.3, 132.7, 131.6, 128.9, 128.1, 127.3, 120.1,
115.0, 55.2, 21.2; HR-MS (ESI): m/z=280.0215
3-Methoxyphenyl Phenyl Telluride
([M]+), calcd. for C14H14O82Se: 280.0212.
4-Methoxyphenyl 2’-Methylphenyl Selenide
1H NMR (400 MHz, CDCl3): d=7.71 (d, J=9.2 Hz,
2H), 7.31–7.20 (m, 5H), 7.12 (t, J=7.6 Hz, 1H), 6.81
(d, J=8.4 Hz, 1H), 3.74 (s, 3H); 13C NMR (100 MHz,
CDCl3): d=159.9, 138.2, 130.2, 130.1, 129.5, 128.0,
1H NMR (400 MHz, CDCl3): d=7.45 (d, J=8.8 Hz, 123.0, 113.8, 55.2; HR-MS (ESI): m/z=313.9957
2H), 7.15–7.13 (m, 1H), 7.11–7.06 (m, 2H), 7.00–6.96 ([M]+), calcd. for C13H12O130Te: 313.9950.
(m, 1H), 6.85 (d, J=9.2 Hz, 2H), 3.79 (s, 3H), 2.37 (s,
3H); 13C NMR (100 MHz, CDCl3): d=159.8, 138.0,
136.6, 134.0, 130.8, 130.0, 126.6, 119.3, 115.3, 55.3,
2-Methoxyphenyl Phenyl Telluride[14]
21.9; HR-MS (ESI): m/z=276.0219 ([M]+), calcd. for
C14H14O78Se: 276.0218.
4-tert-Butylphenyl 4’-Methoxyphenyl Selenide
1H NMR (400 MHz, CDCl3): d=7.88 (d, J=8.0 Hz,
2H), 7.40–7.37 (m, 1H), 7.30–7.26 (m, 2H), 7.18–7.14
(m, 1H), 6.93 (d, J=7.6 Hz, 1H), 6.77 (d, J=8.0 Hz,
1H NMR (400 MHz, CDCl3): d=7.48 (d, J=8.8 Hz, 1H), 6.72 (t, J=7.6 Hz, 1H), 3.85 (s, 3H); 13C NMR
2H), 7.26 (q, J=8.8, 10.0 Hz, 4H), 6.83 (d, J=8.8 Hz, (100 MHz, CDCl3): d=157.9, 141.1, 133.4, 129.5,
2H), 3.78 (s, 3H), 1.28 (s, 9H); 13C NMR (100 MHz, 128.6, 128.0, 122.3, 111.9, 109.5, 107.6, 55.8.
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Adv. Synth. Catal. 2009, 351, 1586 – 1594

Iron-Catalyzed Ligand-Free Carbon-Selenium (or Tellurium) Coupling of Arylboronic Acids
FULL PAPERS
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1H NMR (400 MHz, CDCl3): d=7.81–7.78 (m, 4H),
7.59 (d, J=8.4 Hz, 2H), 7.36 (t, J=6.8 Hz, 1H), 7.26
(t, J=7.2 Hz, 2H), 3.88 (s, 3H); 13C NMR (100 MHz,
CDCl3): d=166.9, 139.5, 135.9, 130.1, 129.8, 129.0,
128.7, 123.4, 113.4, 52.2.
Benzyl 4-Methoxyphenyl Selenide[32]
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1H NMR (400 MHz, CDCl3): d=7.28 (d, J=8.4 Hz,
2H), 7.16–7.09 (m, 3H), 7.04 (d, J=6.8 Hz, 2H), 6.69
(d, J=8.8 Hz, 2H), 3.92 (s, 2H), 3.70 (s, 3H);
13C NMR (100 MHz, CDCl3): d=159.5, 139.1, 136.5,
128.8, 128.3, 126.6, 120.0, 114.6, 55.2, 33.1.
Acknowledgements
We gratefully acknowledge financial support by the National
Natural Science Foundation of China (No. 20772043).
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