Negishi cross-coupling reaction as a simple and efficient route to functionalized amino and alkoxy carbene complexes of chromium, molybdenum, and Tungsten

Article abstract of DOI:10.1021/om500925m

Synthesis of functionalized phenyl, 2-thienyl, and N-methyl-pyrrol-2-yl Fischer carbene complexes of chromium and tungsten was achieved via a Negishi cross-coupling reaction of metalated aminocarbenes in the presence of a palladium catalyst. The reverse a

Full text of DOI:10.1021/om500925m

Article
pubs.acs.org/Organometallics
Negishi Cross-Coupling Reaction as a Simple and Efficient Route to
Functionalized Amino and Alkoxy Carbene Complexes of Chromium,
Molybdenum, and Tungsten
Tomas Tobrman, Ivana Juraskova, and Dalimil Dvorak*
́
̌
́
́
̌
́
́
Department of Organic Chemistry, Institute of Chemical Technology, Prague, Technicka 5, 166 28 Prague 6, Czech Republic
S
* Supporting Information
ABSTRACT: Synthesis of functionalized phenyl, 2-thienyl, and
N-methyl-pyrrol-2-yl Fischer carbene complexes of chromium and
tungsten was achieved via a Negishi cross-coupling reaction of
metalated aminocarbenes in the presence of a palladium catalyst.
The reverse approach, i.e., coupling bromocarbenes with organo-
zinc reagents, is also feasible and is particularly useful with
alkoxycarbene complexes, metalation of which is not possible.
Both these procedures are also suitable for the cross-coupling of
molybdenum amino- and alkoxycarbene complexes. The
presented methodology enables an access to the new amino and
alkoxy carbene complexes bearing aldehyde, ketone, nitrile, and
ester functionality.
Scheme 1. Negishi Cross-Coupling of Metalated
Aminocarbene Complexes
INTRODUCTION
■
Thermal1 and photochemical2 reactions of Fischer carbene
complexes of chromium and tungsten have found a number of
applications in the synthesis of complex organic molecules.
Some of these reactions are moderated by other transition
metals and involve transfer of a carbene ligand to the late
transition metals, including copper,3 gold,4 nickel,3c,5,6 palla-
dium7,8 and rhodium.6a,b,8c,9,10 Relatively little attention has
been paid to the transition-metal-mediated modifications of
already formed carbene complexes. For instance, ring-closing
metathesis was used for the synthesis of complexes with
attached carbocycles or heterocycles,11 and Fischer biscarbene
complexes were prepared by oxidative cross-coupling12 and by
click chemistry.13 Little is known about palladium-catalyzed C−
C cross-coupling reactions of Fischer alkoxy and amino carbene
complexes. To the best of our knowledge, the only reported
examples are the Stille reaction of stannylated
[(dimethylamino)(ethynyl)methylene]tungsten(0) carbene14
and palladium-catalyzed allylic substitution, in which an anion
of chromium aminocarbene complexes serve as the nucleo-
phile.15
RESULTS AND DISCUSSION
■
Due to the reported facile chromium to palladium trans-
metalation of the carbene moiety,7,8 the stability of 1a in THF
at room temperature in the presence of palladium catalysts was
monitored using 1H NMR with benzaldehyde dimethylacetal as
the internal standard. Negligible decomposition was observed
within 1 h, and during 24 h, the content of 1a decreased to 87%
(Pd(dba)2) and 79% (Pd(PPh3)4), respectively.
Recently, we have observed that heterocyclic aminocarbene
complexes 1a−d can be smoothly lithiated using BuLi at −78
°C. The formed lithiated carbenes 2a−d can be alkylated by
primary alkyl halides and/or transformed to secondary and
tertiary alcohols by the reaction with aldehydes or ketones, or
acylated giving ketones.16 The feasibility of the lithiation of 1a−
d led us to explore the potential of these lithiated carbene
complexes in Negishi cross-coupling reactions (Scheme 1).
Received: September 8, 2014
© XXXX American Chemical Society
A
dx.doi.org/10.1021/om500925m | Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
The observed stability of 1a in the presence of Pd-catalysts
encouraged us to study the ability of the lithiated carbenes 2a−
c to react with aryl and alkenyl halides under Negishi reaction
conditions. Thus, the aminocarbene 1a was treated with
butyllithium at −78 °C, followed by transmetalation with
ZnBr2. The formed organozinc reagent was then reacted with 4-
iodonitrobenzene under various conditions (Scheme 1, Table
1). The Pd(PPh3)4 appeared to be the best catalyst giving a full
expected coupled products in yields ranging from 56% to 72%
(Table 1, entries 15−18). This methodology, demonstrated by
the reaction of 1d with 4-iodoacetophenone and 2-bromopyr-
idine, can be extended to the tungsten carbene complexes,
furnishing the coupled products 3o,p even in somewhat higher
yields compared to their chromium analogues (Table 1, entries
19 and 20).
Starting from the easily available bromocarbene 4a,8a the
developed protocol also enables the synthesis of substituted
biphenyls bearing an aminocarbene moiety (Scheme 2). In this
Table 1. Negishi Cross-Coupling Reaction of Metalated
a
Aminocarbenes 1a−d
Scheme 2. Cross-Coupling of Metalated 4-
Bromophenylcarbenes 4a and 4b with Alkyl Halides
b
entry
1, RX
3, yield (%)
1
1a, 4-NO2C6H4I
3a, 85
3a, 78
2
1a, 4-NO2C6H4I
c
3
1a, 4-NO2C6H4I
3a, 66
d
4
1a, 4-NO2C6H4I
3a, 15
e
5
1a, 4-NO2C6H4I
3a, 9
6
1a, C6H5I
3b, 83
3c, 60
3d, 64
7
1a, 4-CH3C6H4I
8
1a, 4-(CH3)2NC6H4I
1a, 2-CH3C6H4I
f
9
3e, 74
10
11
12
13
14
15
16
17
18
19
20
1a, 4-(HCO)C6H4I
1a, 4-(CH3CO)C6H4I
1a, 4-MeO2CC5H4I
1a, 2-BrC5H4N
3f, 74
3g, 72
3h, 43
3i, 71
3j, 78
3k, 72
3l, 72
3m, 64
3n, 56
3o, 83
3p, 78
1a, (Z)-EtO2CCHCHI
1b, 4-(CH3CO)C6H4I
1b, 2-BrC5H4N
1c, 4-(CH3CO)C6H4I
1c, 4-(HCO)C6H4I
1d, 4-(CH3CO)C6H4I
1d, 2-BrC5H4N
way, biphenylaminocarbenes bearing formyl, acetyl, and ester
groups 5a−c were obtained in 65−77% yield (Table 2, entries
Table 2. Cross-Coupling Reaction of Metalated
a
Reaction conditions: 5 mol % of the Pd(PPh3)4, THF, ambient
Phenylcarbenes 4a and 4b with Alkyl Halides Catalyzed by
Pd(PPh3)4
b
c
a
temperature, 3 h. Isolated yield. 5 mol % of the Pd(dba)2/TFP was
used. 5 mol % of the Pd(dba)2 was used. 5 mol % of the Pd(tBu3P)2
was used. Reaction time was 20 h.
d
e
b
f
entry
4, RX
5, yield (%)
1
2
3
4
5
6
7
4a, 4-(HCO)C6H4I
4a, 4-(CH3CO)C6H4I
4a, 4-EtO2CC6H4I
4a, (Z)-EtO2CCHCHI
4a, 2-BrC5H4N
5a, 65
5b, 77
5c, 72
5d, 71
5e, 85
5f, 52
5g, 60
conversion and 85% isolated yield of the expected product 3a
within 3 h (Table 1, entry 1). An extension of the reaction time
to 20 h slightly lowered the yield of 3a to 78% (Table 1, entry
2). The use of Pd(dba)2 with tri(2-furyl)phosphine (TFP) gave
only a moderate yield of 3a (Table 1, entry 3), while the yields
with Pd(dba)2 or Pd(t-Bu3P)2 were low (Table 1, entries 4 and
5).
4b, 4-(CH3CO)C6H4I
4b, 2-BrC5H4N
a
Reaction conditions: 5 mol % of the catalyst, THF, ambient
temperature, 3 h. Isolated yield.
b
The best reaction conditions (Pd(PPh3)4, 3 h) were used to
examine the scope of this reaction. Thus, the iodobenzene was
converted to 3b in 83% yield (Table 1, entry 6). Iodobenzenes
bearing electron-donating groups yielded the expected products
3c,d in good yields (Table 1, entries 7 and 8). In the case of 2-
iodotoluene, the reaction time had to be extended to 20 h to
reach the full conversion. The product 3e was then obtained
with a yield of 74% (Table 1, entry 9). Similarly, high yields
were obtained with iodobenzenes containing electron-with-
drawing substituents (Table 1, entries 10−12) and with 2-
bromopyridine (Table 1, entry 13). The only exception was
methyl-4-iodobenzoate, which gave only 43% yield of 3h
(Table 1, entry 12). The reaction with (Z)-ethyl-3-iodoprope-
noate furnished the corresponding carbene 3j in 78% yield
(Table 1, entry 14) with full retention of the configuration on
the double bond. Pyrrole and furane-derived carbenes 1b,c also
reacted easily with 4-iodoacetophenone, 4-iodobenzaldehyde,
or 2-bromopyridine under the above conditions, giving the
1−3). The reaction with (Z)-ethyl-3-iodopropenoate pro-
ceeded smoothly, furnishing 5d in 71% yield with the retention
of the double-bond configuration (Table 2, entry 4).
Furthermore, 2-bromopyridine was a good substrate for this
reaction, giving the coupled product 5e in 85% yield (Table 2,
entry 5). In contrast, the tungsten bromoaminocarbene 4b16
afforded only moderate yields of the coupled products 5f,g in
the reaction with 4-iodoacetophenone and 2-bromopyridine
(Table 2, entries 6 and 7).
We also focused on the reverse experimental setup of the
Negishi cross-coupling reaction based on the reaction of
bromocarbenes with alkyl or arylzinc bromides. The reactivity
of the aminocarbene complexes 4a and 1e was examined first
(Scheme 3). To our surprise, the Pd(PPh3)4-catalyzed reaction
of aminocarbene 1e with butylzinc bromide, prepared by
reaction of butyllithium with zinc bromide, afforded the
B
dx.doi.org/10.1021/om500925m | Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
Scheme 3. Cross-Coupling of Bromoaminocarbenes 1e and
4a with Organozinc Reagents
Table 4. Negishi Reaction of Bromoalkoxycarbene
Complexes 6a−c (Scheme 4)
a
1
expected product in only trace amounts. According to H
NMR, 30% of the unreacted 1e remained in the reaction
mixture after 3 h along with products of its decomposition. The
decomposition also occurred when Pd[P(t-Bu)3]2 or PEPPSI-
iPr were used as catalysts. However, the reaction catalyzed with
PdCl2XantPhos proceeded smoothly, affording the desired
product in 62% isolated yield (Table 3, entry 1). The aromatic
Table 3. Cross-Coupling Reaction of Aminocarbenes 1e and
a
4a with Organozinc Reagents Catalyzed by PdCl2XantPhos
b
entry
bromocarbene, R
product, yield (%)
1
2
3
4
5
1e, CH3(CH2)3
3q, 62
3h, 62
3d, 64
5c, 74
5e, 52
1e, 4-CH3O2CC6H4
1e, 4-(CH3)2NC5H4
4a, 4-EtO2CC6H4
4a, 2-pyridyl
a
Reaction conditions: 5 mol % of the catalyst, THF, ambient
b
temperature, 3 h. Isolated yield.
a
zinc bromides containing electron-withdrawing or -donating
groups reacted similarly (Table 3, entries 2 and 3) and also did
pentacarbonyl[(N,N-dimethylamino)(4-bromophenyl)-
methylene]chromium(0) (4a), giving the coupled products
derived from 4-ethoxycarbonylphenyl and 2-pyridyl zinc
bromides (Table 3, entries 4 and 5).
Reaction conditions: 1.0 equiv of RZnBr prepared from RLi and
ZnBr2, Pd(PPh3)4 (5 mol %), THF, ambient temperature, 3 h.
Isolated yield. 1.1 equiv of butylzinc bromide was used. Arylzinc
b
c
d
bromide was prepared by reaction of arylmagnesium chloride with
ZnBr2.
Next, we turned our attention to the alkoxycarbene
complexes. These compounds are not compatible with
organolithium reagents and, therefore, cannot be used for the
preparation of the corresponding organozinc reagents. The
reaction of halogenated carbene complexes thus becomes the
only way to obtain the coupled products (Scheme 4).
expected product 7b in 90% isolated yield (Table 4, entry 3). In
contrast, phenylzinc bromide, generated by the reaction of
phenylmagnesium chloride with ZnBr2, furnished 7b in 69%
yield (Table 4, entry 4). In addition, other organozinc reagents
derived from 2-bromo-6-methoxynaphthalene, 5-chlorothio-
phene and phenylacetylene were successfully coupled with
alkoxycarbene 6a (Table 4, entries 5−7). In the case of 2-
iodotoluene, the reaction required 20 h to achieve full
conversion and 42% yield (Table 4, entry 8). 5-Vinyl-
alkoxycarbene 7g was prepared starting from vinylmagnesium
chloride in 68% yield (Table 4, entry 9). The recently
introduced chemistry of the Turbo Grignard reagent17 enabled
the preparation of functionalized Grignard reagents derived
from ethyl 4-iodobenzoate and 4′-iodobiphenyl-4-carbonitrile.
The subsequent transmetalation with ZnBr2 and reaction with
6a catalyzed by Pd(PPh3)4 led to the functionalized
alkoxycarbenes 7h and 7i in good yields (Table 4, entries 10
and 11). The furan-derived chromium alkoxycarbene 6b and
the tungsten alkoxycarbene complex of thiophene 6c reacted
smoothly with organozinc reagents giving the corresponding
coupled products (Table 4, entries 12−15). In contrast to other
alkoxycarbene complexes, the pyrrole-based carbene 6d failed
to give the expected product of the cross-coupling reaction. 1H
NMR analysis along with HR MS of the crude reaction mixture
confirmed that Pd-catalyzed dimerization of alkoxycarbenes
occurred. Similarly, attempts to use pentacarbonyl[(ethoxy)(4-
bromophenyl)methylene]chromium (8) as a cross-coupling
Scheme 4. Cross-Coupling of Bromoethoxycarbenes 6a−d
with Organozinc Reagents
In this case, the alkoxycarbene complex 6a reacted smoothly
with butylzinc bromide under Pd(PPh3)4 catalysis giving the
corresponding product in 67% yield (Table 4, entry 1). Using
an excess of alkoxycarbene 6 in this type of cross-coupling
reaction turned out to be important. If an excess of butyl zinc
bromide was used, the yield of 7a became lower than 10%
(Table 4, entry 2). The reaction of phenylzinc bromide,
prepared from phenyllithium, with alkoxycarbene 6a gave the
C
dx.doi.org/10.1021/om500925m | Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
partner in the reaction with butylzinc bromide failed. Similarly,
the analysis of the crude reaction mixture showed the formation
of a complex mixture in which the product of self-dimerization
of 8 was detected by mass spectrometry. These findings are in
accordance with the reported ability of aryl alkoxycarbenes to
undergo Pd-catalyzed self-dimerization.7c
of the carbene ligands. The cross-coupling reactions presented
here allow the preparation of a number of new functionalized
aminocarbene and alkoxycarbene complexes of chromium and
tungsten that are not easily accessible by other methods.
EXPERIMENTAL SECTION
■
As Scheme 5 shows, the cross-coupling methodology has
been also successfully used for the derivatization of both alkoxy-
General Information. All reactions were performed under an
argon atmosphere. The solvents were dried and degassed by standard
procedures; silica gel (Merck, Geduran Si 60, 63−200 μm) was used
for column chromatography. Pentacarbonyl[(N,N-dimethylamino)(2-
thienyl)carbene]chromium(0) (1a),18 pentacarbonyl[(N,N-
dimethylamino)(5-bromo-1-methyl-2-pyrrolyl)carbene]chromium(0)
(1b),16 pentacarbonyl[(N,N-dimethylamino)(2-furyl)carbene]-
chromium(0) (1c),18 pentacarbonyl[(N,N-dimethylamino)(2-
thienyl)carbene]tungsten(0) (1d),16 pentacarbonyl[(N,N-
dimethylamino)(4-bromophenyl)carbene]chromium(0) (4a),8a
pentacarbonyl[(N,N-dimethylamino)(4-bromophenyl)carbene]-
Scheme 5. Cross-Coupling of Molybdenum Carbene
Complexes
tungsten(0)(4b),16 pentacarbonyl[(N,N-dimethylamino)(5-bromo-2-
thienyl)carbene]chromium(0) (1e), and
16
pentacarbonyl[(ethoxy)-
(4-bromophenyl)methylene]chromium (8)8a were prepared by the
reported procedures; other compounds were purchased.
General Procedure A for the Pd-Catalyzed Negishi Cross-
Coupling Reaction of Zincated Fischer Aminocarbene Com-
plexes. Butyllithium (1.3 equiv) was added to a solution of carbene
complex 1a−d, 4a,b or 9 (1.0 equiv) in dry THF (10 mL/mmol)
cooled to −78 °C. The resultant mixture was stirred for 30 min at −78
°C followed by addition of the solution of ZnBr2 (1.0 equiv) in dry
THF (0.5 M solution). After 30 min at −78 °C, a solution of halide
(2.0 equiv) and Pd(PPh3)4 (5 mol %) in dry THF (2 mL/mmol) was
added. The resultant mixture was warmed to ambient temperature and
stirred for 3 h. The mixture was then quenched with brine, the organic
layer was separated, and the water layer was extracted with ether.
Combined organic layers were dried (MgSO4) and concentrated in
vacuo, and the crude product was subjected to column chromatog-
raphy on silica gel.
General Procedure B for the Cross-Coupling Reaction of
Halogenated Amino and Alkoxycarbenes with Organozinc
Reagents. The Preparation of the Organozinc Reagents via Li/Zn
Transmetalation. Commercially unavailable alkenyl-, alkynyl-, or
aryllithium reagents were prepared by the reaction of BuLi (1.1 equiv)
with a solution of aryl- or alkenylhalides or phenylacetylene (1.0
equiv) in dry THF (4 mL/mmol) cooled to −78 °C. The resultant
mixture was then stirred for 30 min at −78 °C, followed by addition of
the solution of freshly dried ZnBr2 (1.0 equiv) in dry THF (2 mL/
mmol). After 30 min at −78 °C, the formed organozinc reagent was
used in the cross-coupling reaction.
The Preparation of the Organozinc Reagent via Mg/Zn
Transmetalation. Commercially unavailable alkylmagnesium halides
reagents were prepared by reaction of iPrMgCl·LiCl (1.05 equiv) with
a solution of arylhalides (1.0 equiv) in dry THF (4 mL/mmol) cooled
to −40 °C. The resultant mixture was then stirred for 30 min at −40
°C, followed by addition of the solution of freshly dried ZnBr2 (1.0
equiv) in dry THF (2 mL/mmol). After 30 min at −40 °C, the formed
organozinc reagent was used in the cross-coupling reaction.
The solution of alkoxycarbene 6a−c, 10 (1.1 equiv) and Pd(PPh3)4
(5 mol %) in dry THF (2 mL/mmol) was added to the freshly
prepared solution of organozinc reagent (1.0 equiv) cooled to −78 °C.
The resultant mixture was stirred for 3 h at ambient temperature. In
the case of aminocarbene complexes, a solution of aminocarbene 1e or
4a (1.0 equiv) and PdCl2XantPhos (5 mol %) was added to the
solution of organozinc reagent (1.2 equiv). The resultant mixture was
stirred for 3 h at ambient temperature and quenched with brine, and
the water layer was extracted with ether (3 × 30 mL). Combined
organic layers were dried (MgSO4) and concentrated in vacuo, and
column chromatography (silica gel) afforded the product.
Pentacarbonyl{(N,N-dimethylamino)[5-(4-nitrophenyl)-2-
thienyl]methylene}chromium(0) (3a). The general procedure A
starting from 1a (0.100 g, 0.30 mmol), BuLi (0.16 mL, 0.39 mmol),
ZnBr2 (0.068 g, 0.30 mmol), 4-nitro-1-iodobenzene (0.149 g, 0.60
mmol) and Pd(PPh3)4 (0.017 g, 0.015 mmol) followed by column
and aminocarbene complexes of molybdenum. The obtained
results are comparable with that obtained with those chromium
and tungsten carbenes.
CONCLUSION
■
The aminocarbene complexes of chromium and tungsten
bearing 2-thienyl, N-methyl-5-bromopyrrol-2-yl, or 4-bromo-
phenyl groups can be, after lithiation with butyllithium at −78
°C and transmetalation with zinc bromide, used in Pd-catalyzed
Negishi reactions with aryl, heteroaryl, and alkenyl halides. The
reverse approach, i.e., the reaction of halogenated carbene
complexes with alkyl, alkenyl, aryl, and heteroaryl zinc
bromides, can be used not only for the coupling of
aminocarbenes but also for alkoxycarbene complexes, lithiation
of which is problematic. Thus, besides aminocarbene complexes
of chromium bearing 5-bromo-2-thienyl (1e) and 4-bromo-
phenyl (4a) groups, [ethoxy(5-bromo-2-thienyl)methylene]-
chromium (6a), [ethoxy(5-bromo-2-furyl)methylene]-
chromium (6b), and [ethoxy(5-bromo-2-thieyl)methylene]-
tungsten (6c) were also successfully coupled with organozinc
reagents. The molybdenum amino- and alkoxycarbene
complexes derived from thiophene can be also successfully
subjected to the above-discussed cross-coupling procedures. In
contrast, pentacarbonyl[ethoxy(N-methyl-5-bromo-2-pyrrolyl)-
methylene]chromium (6d) and pentacarbonyl[(ethoxy)(4-
bromophenyl)methylene]chromium (8) failed to give the
coupled products and afforded only products of dimerization
D
dx.doi.org/10.1021/om500925m | Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
chromatography (silica gel, DCM/hexane 1/2 then 2/1) afforded
0.115 g of the title compound (85%) as an orange solid. Mp: >120 °C
dec. 1H NMR (CDCl3): δ 3.32 (s, 3H, CH3), 4.03 (s, 3H, CH3), 6.56
(d, J = 3.6 Hz, 1H, CH), 7.37 (d, J = 3.6 Hz, 1H, CH), 7.69 (d, J = 9.0
Hz, 2H, CH), 8.24 (d, J = 9.0 Hz, 2H, CH). 13C NMR (DMSO-d6): δ
47.3, 51.8, 120.4, 124.8, 125.8, 127.2, 139.5, 139.7, 146.3, 154.5, 216.8,
223.8, 258.6. IR (ATR): ν 2053 (m), 1937 (m), 1906 (s), 1882 (s),
1591 (w), 1548 (w), 1513 (m), 1449 (w), 1401 (w), 1327 (m), 1263
(w), 1214 (w), 1164 (w), 1107 (w) cm−1. Anal. Calcd for
C18H12CrN2O7S: C, 47.79; H, 2.67; N, 6.19; S, 7.09. Found: C,
47.51; H, 2.67; N, 6.03; S, 6.83.
Pentacarbonyl[(N,N-dimethylamino)(5-phenyl-2-thienyl)-
methylene]chromium(0) (3b). The general procedure A starting
from 1a (0.150 g, 0.45 mmol), BuLi (0.24 mL, 0.59 mmol), ZnBr2
(0.101 g, 0.45 mmol), iodobenzene (0.184 g, 0.9 mmol) and
Pd(PPh3)4 (0.026 g, 0.023 mmol) followed by column chromatog-
raphy (silica gel, DCM/hexane 1/2) afforded 0.152 g of the title
compound (83%) as a yellow solid. Mp: >81 °C dec. 1H NMR
(CDCl3): δ 3.31 (s, 3H, CH3), 4.00 (s, 3H, CH3), 6.51 (d, J = 3.9 Hz,
1H, CH), 7.21 (d, J = 3.9 Hz, 1H, CH), 7.31 (m, 1H, CH), 7.38 (m,
2H, CH), 7.58 (m, 2H, CH). 13C NMR (CDCl3): δ 46.7, 51.4, 119.3,
122.8, 125.5, 127.8, 129.0, 133.5, 143.2, 151.8, 216.8, 223.6, 269.4. IR
(ATR): ν 2052 (w), 1974 (w), 1886 (s), 1716 (w), 1599 (w), 1525
(w), 1492 (w), 1453 (w), 1397 (w), 1255 (w), 1222 (w), 1159 (w),
1104 (w) cm−1. Anal. Calcd for C18H13CrNO5S: C, 53.07; H, 3.22; N,
3.44. Found: C, 53.18; H, 3.51; N, 3.32.
CH3), 3.35 (s, 3H, CH3), 4.01 (s, 3H, CH3), 6.53 (d, J = 3.6 Hz, 1H,
CH), 6.94 (d, J = 3.6 Hz, 1H, CH), 7.26−7.29 (m, 3H, CH3), 7.40−
7.42 (m, 1H, CH). 13C NMR (CDCl3): δ 21.1, 46.7, 51.3, 118.3,
125.9, 126.1, 128.1, 130.2, 130.8, 133.0, 136.2, 142.1, 152.7, 216.8,
223.7, 269.3. IR (ATR): ν 2052 (m), 1984 (m), 1882 (s), 1616 (m),
1517 (m), 1460 (m), 1395 (m), 1221 (w), 1154 (w), 1098 (w), 1037
(w) cm−1. Anal. Calcd for C19H15CrNO5S: C, 54.16; H, 3.59; N, 3.32;
S, 7.61. Found: C, 54.64; H, 3.66; N, 3.36; S, 8.05.
Pentacarbonyl(N,N-dimethylamino)[5-(4-formylphenyl)-2-
thienyl]methylene}chromium(0) (3f). The general procedure A
starting from 1a (0.150 g, 0.45 mmol), BuLi (0.24 mL, 0.59 mmol),
ZnBr2 (0.101 g, 0.45 mmol), 4-iodobenzaldehyde (0.248 g, 0.9 mmol)
and Pd(PPh3)4 (0.026 g, 0.023 mmol) followed by column
chromatography (silica gel, DCM/hexane, 1/2 to 2/1) afforded
0.145 g of the title compound (74%) as an orange solid. Mp: >110 °C
dec. 1H NMR (CDCl3): δ 3.31 (s, 3H, CH3), 4.01 (s, 3H, CH3), 6.54
(d, J = 3.9 Hz, 1H, CH), 7.35 (d, J = 3.9 Hz, 1H, CH), 7.70 (d, J = 8.1
Hz, 2H, CH), 7.87 (d, J = 8.1 Hz, 2H, CH), 9.98 (s, 1H, CH). 13C
NMR (CDCl3): δ 46.8, 51.4, 119.5, 125.0, 125.6, 130.4, 135.2, 139.3,
141.2, 153.5, 191.2, 216.6, 223.4, 269.0. IR (ATR): ν 2053 (w), 1973
(w), 1888 (w), 1691 (m), 1600 (m), 1541 (w), 1451 (w), 1399 (w),
1307 (w), 1261 (w), 1210 (w), 1164 (w) cm−1. Anal. Calcd for
C19H13CrNO6S: C, 52.42; H, 3.01; N, 3.22; S, 7.36. Found: C, 51.97;
H, 3.06; N, 3.12; S, 7.36.
Pentacarbonyl{(N,N-dimethylamino)[5-(4-acetylphenyl)-2-
thienyl]methylene}chromium(0) (3g). The general procedure A
starting from 1a (0.150 g, 0.45 mmol), BuLi (0.24 mL, 0.59 mmol),
ZnBr2 (0.101 g, 0.45 mmol), 4-iodoacetophenone (0.221 g, 0.9 mmol)
and Pd(PPh3)4 (0.026 g, 0.023 mmol) followed by column
chromatography (silica gel, DCM/hexane 1/2 then 2/1) afforded
0.146 g of the title compound (72%) as an orange solid. Mp: >92 °C
dec. 1H NMR (CDCl3): δ 2.60 (s, 3H, CH3), 3.30 (s, 3H, CH3), 4.00
(s, 3H, CH3), 6.53 (d, J = 3.9 Hz, 1H, CH), 7.31 (d, J = 3.6 Hz, 1H,
CH), 7.63 (d, J = 8.4 Hz, 2H, CH), 7.95 (d, J = 8.7 Hz, 2H, CH). 13C
NMR (CDCl3): δ 26.5, 46.8, 51.4, 119.4, 124.5, 125.2, 129.1, 135.8,
137.9, 141.4, 153.1, 197.2, 216.6, 223.5, 268.7. IR (ATR): ν 2051 (m),
1975 (w), 1949 (m), 1909 (s), 1878 (s), 1673 (m), 1598 (m), 1539
(w), 1451 (w), 1398 (w), 1355 (w), 1254 (w), 1215 (w), 1177 (w),
1101 (w) cm−1. Anal. Calcd for C20H15CrNO6S: C, 53.45; H, 3.47; N,
3.12. Found: C, 53.10; H, 3.63; N, 2.89.
Pentacarbonyl{(N,N-dimethylamino)[5-(4-methoxycarbonyl-
phenyl)-2-thienyl]methylene}chromium(0) (3h). The general
procedure A starting from 1a (0.150 g, 0.45 mmol), BuLi (0.24 mL,
0.59 mmol), ZnBr2 (0.101 g, 0.45 mmol), methyl 4-iodobenzoate
(0.236 g, 0.9 mmol) and Pd(PPh3)4 (0.026 g, 0.023 mmol) followed
by column chromatography (silica gel, DCM/hexane, 1/2 to 2/1)
afforded 0.130 g of the title compound (43%) as a yellow solid. Mp:
>90 °C dec. Alternatively, the title compound was prepared following
the general procedure B starting from 1d (0.340 g, 0.83 mmol),
iPrMgCl·LiCl (0.85 mL, 1.05 mmol), ZnBr2 (0.225 g, 1.0 mmol),
methyl 4-iodobenzoate (0.262 g, 1.0 mmol) and PdCl21XantPhos
(0.031 g, 0.042 mmol) giving 0.241 g of the 3h (62%). H NMR
(CDCl3): δ 3.30 (s, 3H, CH3), 3.92 (s, 3H, CH3), 4.00 (s, 3H, CH3),
6.52 (d, J = 3.3 Hz, 1H, CH), 7.30 (d, J = 3.3 Hz, 1H, CH), 7.61 (d, J
= 8.4 Hz, 2H, CH), 8.03 (d, J = 8.1 Hz, 2H, CH). 13C NMR (CDCl3):
δ 46.8, 51.4, 52.1, 119.4, 124.4, 125.1, 129.0, 130.3, 137.8, 141.7, 153.0,
166.5, 216.7, 223.5, 269.2. IR (ATR): ν 2052 (m), 1982 (w), 1881
(w), 1712 (m), 1600 (w), 1529 (w), 1432 (w), 1401 (w), 1281 (w),
1256 (w), 1215 (w), 1178 (w), 1098 (w) cm−1. Anal. Calcd for
C20H15CrNO7S: C, 51.61; H, 3.25; N, 3.01. Found: C, 51.50; H, 3.31;
N, 2.77.
Pentacarbonyl{(N,N-dimethylamino)[5-(4-methylphenyl)-2-
thienyl]methylene}chromium(0) (3c). The general procedure A
starting from 1a (0.150 g, 0.45 mmol), BuLi (0.24 mL, 0.59 mmol),
ZnBr2 (0.101 g, 0.45 mmol), 4-iodotoluene (0.196 g, 0.9 mmol) and
Pd(PPh3)4 (0.026 g, 0.023 mmol) followed by column chromatog-
raphy (silica gel, DCM/hexane 1/2 then 2/1) afforded 0.114 g of the
1
title compound (60%) as a yellow solid. Mp: >100 °C dec. H NMR
(CDCl3): δ 2.38 (s, 3H, CH3), 3.30 (s, 3H, CH3), 4.00 (s, 3H, CH3),
6.49 (d, J = 3.6 Hz, 1H, CH), 7.16 (d, J = 3.6 Hz, 1H, CH), 7.19 (d, J
= 8.1 Hz, 2H, CH), 7.47 (d, J = 7.8 Hz, 2H, CH). 13C NMR (CDCl3):
δ 21.2, 46.7, 51.4, 119.3, 122.2, 125.5, 129.6, 130.7, 137.7, 143.5, 151.3,
216.8, 223.6, 269.3. IR (ATR): ν 2918 (w), 2051 (m), 1879 (s), 1521
(w), 1444 (w), 1398 (w), 1256 (w), 1211 (w), 1171 (w), 1102 (w),
1049 (w) cm−1. Anal. Calcd for C19H15CrNO5S: C, 54.16; H, 3.59; N,
3.32. Found: C, 54.11; H, 3.63; N, 3.32.
Pentacarbonyl{(N,N-dimethylamino)[5-(4-(N′,N′-
dimethylamino)phenyl)-2-thienyl]methylene}chromium(0)
(3d). The general procedure A starting from 1a (0.150 g, 0.45 mmol),
BuLi (0.37 mL, 0.59 mmol), ZnBr2 (0.101 g, 0.45 mmol), N,N-
dimethyl-4-iodoaniline (0.168 g, 0.68 mmol) and Pd(PPh3)4 (0.026 g,
0.023 mmol) followed by column chromatography (silica gel, DCM/
hexane 1/2 then 2/1) afforded 0.130 g of the title compound (64%) as
a yellow solid. Mp: >85 °C dec. Alternatively, the title compound was
prepared following the general procedure B starting from 1d (0.340 g,
0.83 mmol), BuLi (0.43 mL, 1.05 mmol), ZnBr2 (0.225 g, 1.0 mmol),
N,N-dimethyl-4-bromoaniline (0.200 g, 1.0 mmol) and
PdCl2XantPhos (0.031 g, 0.042 mmol) followed by column
chromatography (silica gel, DCM/hexane 1/2 then 2/1) giving
0.240 g of 3d (64%). 1H NMR (CDCl3): δ 2.99 (s, 6H, CH3), 3.31 (s,
3H, CH3), 3.98 (s, 3H, CH3), 6.47 (d, J = 3.6 Hz, 1H, CH), 6.73 (d, J
= 8.4 Hz, 2H, CH), 7.03 (d, J = 3.6 Hz, 1H, CH), 7.46 (d, J = 8.4 Hz,
2H, CH). 13C NMR (CDCl3): δ 40.3, 46.7, 51.3, 112.4, 119.5, 120.3,
121.6, 126.5, 144.6, 149.9, 150.2, 216.9, 223.7, 269.1. IR (ATR): ν
2052 (m), 1972 (w), 1883 (s), 1605 (m), 1507 (m), 1438 (m), 1396
(m), 1362 (m), 1259 (w), 1226 (w), 1191 (w), 1168 (w), 1103 (w)
cm−1. Anal. Calcd for C20H18CrN2O5S: C, 53.33; H, 4.03; N, 6.22; S,
7.12. Found: C, 53.78; H, 4.23; N, 6.04; S, 7.50.
Pentacarbonyl{(N,N-dimethylamino)[5-(2-pyridyl)-2-
thienyl]methylene}chromium(0) (3i). The general procedure A
starting from 1a (0.150 g, 0.45 mmol), BuLi (0.24 mL, 0.59 mmol),
ZnBr2 (0.101 g, 0.45 mmol), 2-bromopyridine (0.142 g, 0.9 mmol)
and Pd(PPh3)4 (0.026 g, 0.023 mmol) followed by column
chromatography (silica gel, DCM/hexane 1/2) afforded 0.135 g of
Pentacarbonyl{(N,N-dimethylamino)[5-(2-methylphenyl)-2-
thienyl]methylene}chromium(0) (3e). The general procedure A
starting from 1a (0.150 g, 0.45 mmol), BuLi (0.24 mL, 0.59 mmol),
ZnBr2 (0.101 g, 0.45 mmol), 2-iodotoluene (0.196 g, 0.9 mmol) and
Pd(PPh3)4 (0.026 g, 0.023 mmol) followed by column chromatog-
raphy (silica gel, DCM/hexane 1/2) afforded 0.140 g of the title
1
the title compound (71%) as a yellow solid. Mp: >114 °C dec. H
NMR (CDCl3): δ 3.28 (s, 3H, CH3), 3.98 (s, 3H, CH3), 6.54 (d, J =
3.6 Hz, 1H, CH), 7.11−7.15 (m, 1H, CH), 7.44 (d, J = 3.6 Hz, 1H,
1
compound (74%) as a yellow oil. H NMR (CDCl3): δ 2.45 (s, 3H,
E
dx.doi.org/10.1021/om500925m | Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
CH), 7.90−7.67 (m, 2H, CH), 8.51−8.52 (m, 1H, CH). 13C NMR
(CDCl3): δ 46.7, 51.3, 118.4, 119.3, 122.0, 124.2, 136.6, 143.4, 149.5,
152.0, 154.2, 216.7, 223.6, 269.5. IR (ATR): ν 2054 (m), 1980 (w),
1890 (s), 1581 (m), 1520 (m), 1469 (m), 1431 (m), 1394 (m), 1294
(w), 1218 (w), 1153 (w), 1093 (w) cm−1. Anal. Calcd for
C17H12CrN2O5S: C, 50.00; H, 2.96; N, 6.86; S, 7.85. Found: C,
49.58; H, 2.96, N, 6.70, S, 7.89.
Pentacarbonyl(Z)-{(N,N-dimethylamino)[5-(2-ethoxycarbo-
nylvinyl)-2-thienyl]methylene}chromium(0) (3j). The general
procedure A starting from 1a (0.100 g, 0.30 mmol), BuLi (0.16 mL,
0.39 mmol), ZnBr2 (0.068 g, 0.30 mmol), (Z)-ethyl 3-iodopropenoate
(0.136 g, 0.6 mmol) and Pd(PPh3)4 (0.017 g, 0.015 mmol) followed
by column chromatography (silica gel, DCM/hexane 1/2) afforded
0.100 g of the title compound (78%) as an orange oil. 1H NMR
(CDCl3): δ 1.31 (t, J = 6.9 Hz, 3H, CH3), 3.26 (s, 3H, CH3), 3.98 (s,
3H, CH3), 4.23 (q, J = 6.9 Hz, 2H, CH2), 5.73 (d, J = 12.3 Hz, 1H,
CH), 6.55 (d, J = 3.8 Hz, 1H, CH), 7.04 (d, J = 12.3 Hz, 1H, CH),
7.27 (d, J = 3.8 Hz, 1H, CH). 13C NMR (CDCl3): δ 14.3, 46.9, 51.3,
60.3, 113.1, 118.0, 136.1, 136.5, 136.7, 158.2, 166.6, 216.6, 223.5,
269.3. IR (ATR): ν 2054 (m), 1978 (m), 1903 (s), 1877 (s), 1698
(m), 1601 (m), 1541 (w), 1509 (w), 1452 (w), 1411 (w), 1386 (w),
1178 (m), 1097 (w), 1043 (w), 1032 (w) cm−1. Anal. Calcd for
C17H15CrNO7S: C, 47.55; H, 3.52; N, 3.26; S, 7.47. Found: C, 47.84;
H, 3.80; N, 3.00; S, 6.91.
Pentacarbonyl{(N,N-dimethylamino)[5-(4-formylphenyl)-2-
furyl]methylene}tungsten(0) (3n). The general procedure A
starting from 1c (0.433 g, 1.1 mmol), BuLi (0.59 mL, 1.43 mmol),
ZnBr2 (0.247 g, 1.1 mmol), 4-iodobenzaldehyde (0.510 g, 2.2 mmol)
and Pd(PPh3)4 (0.064 g, 0.055 mmol) followed by column
chromatography (silica gel, DCM/hexane 1/2 then 2/1) afforded
0.260 g of the title compound (56%) as a yellow solid. Mp: >115 °C
dec. 1H NMR (CDCl3): δ 3.47 (s, 3H, CH3), 4.01 (s, 3H, CH3), 6.36
(d, J = 3.3 Hz, 1H, CH), 6.91 (d, J = 3.3 Hz, 1H, CH), 7.86−7.94 (m,
4H, CH), 10.01 (s, 1H, CH). 13C NMR (acetone-d6): δ 49.3, 52.8,
110.4, 111.0, 125.3, 131.3, 136.1, 136.9, 154.8, 160.7, 192.4, 218.4,
225.0, 253.4. Anal. Calcd for C19H13CrNO7: C, 54.42; H, 3.12; N,
3.34. Found: C, 54.78; H, 3.22, N, 3.12.
Pentacarbonyl{(N,N-dimethylamino)[5-(4-acetylphenyl)-2-
thienyl]methylene}tungsten(0) (3o). The general procedure A
starting from 1d (0.463 g, 1. 0 mmol), BuLi (0.59 mL, 1.30 mmol),
ZnBr2 (0.225 g, 1.0 mmol), 4-iodoacetophenone (0.492 g, 2.0 mmol)
and Pd(PPh3)4 (0.058 g, 0.05 mmol) followed by column
chromatography (silica gel, DCM/hexane 1/2 then 2/1) afforded
0.480 g of the title compound (83%) as a yellow solid. Mp: >134 °C
dec. 1H NMR (CDCl3): δ 2.60 (s, 3H, CH3), 3.30 (s, 3H, CH3), 3.94
(s, 3H, CH3), 6.59 (d, J = 3.6 Hz, 1H, CH), 7.34 (d, J = 3.6 Hz, 1H,
CH), 7.62−7.65 (m, 2H, CH), 7.94−7.97 (m, 2H, CH). 13C NMR
(CDCl3): δ 26.5, 45.3, 53.8, 120.3, 124.3, 125.3, 129.1, 135.9, 137.8,
141.7, 154.3, 197.1, 198.1 (J183W−13C = 128 Hz), 203.7, 249.5. IR
(ATR): ν 2058 (m), 1970 (w), 1888 (w), 1674 (m), 1601 (w), 1537
(w), 1444 (w), 1395 (w), 1358 (w), 1258 (w), 1178 (w), 1107 (w),
1020 (w) cm−1. Anal. Calcd for C20H15NO6SW: C, 41.33; H, 2.60; N,
2.41; S, 5.52. Found: C, 41.28; H, 2.67; N, 2.31; S, 5.41.
Pentacarbonyl{(N,N-dimethylamino)[5-(2-pyridyl)-2-
thienyl]methylene}tungsten(0) (3p). The general procedure A
starting from 1d (0.463 g, 1. 0 mmol), BuLi (0.59 mL, 1.30 mmol),
ZnBr2 (0.225 g, 1.0 mmol), 2-bromopyridine (0.492 g, 2.0 mmol) and
Pd(PPh3)4 (0.058 g, 0.05 mmol) followed by column chromatography
(silica gel, DCM/hexane 1/2 then 2/1) afforded 0.420 g of the title
compound (78%) as a yellow solid. Mp: >128 °C dec. 1H NMR
(CDCl3): δ 3.28 (s, 3H, CH3), 3.92 (s, 3H, CH3), 6.58−6.61 (m, 1H,
CH), 7.12−7.16 (m, 1H, CH), 7.45−7.47 (m, 1H, CH), 7.60−7.71
(m, 2H, CH), 8.52−8.54 (m, 1H, CH). 13C NMR (CDCl3): δ 45.2,
53.8, 118.5, 120.2, 122.1, 124.1, 136.6, 143.7, 149.5, 151.9, 155.3, 198.1
(J183W−13C = 128 Hz), 203.8, 250.3. IR (ATR): ν 2060 (m), 1978 (w),
1883 (s), 1582 (w), 1533 (w), 1469 (w), 1430 (w), 1400 (w), 1293
(w), 1218 (w), 1154 (w), 1106 (w) cm−1. Anal. Calcd for
C17H12N2O5SW: C, 37.80; H, 2.24; N, 5.19; S, 5.94. Found: C,
37.82; H, 2.30; N, 5.14; S, 5.95.
Pentacarbonyl[(N,N-dimethylamino)(4′-formyl-4-biphenyl)-
methylene]chromium(0) (5a). The general procedure A starting
from 4a (0.202 g, 0.50 mmol), BuLi (0.27 mL, 0.65 mmol), ZnBr2
(0.113 g, 0.50 mmol), a solution of 4-iodobenzaldehyde (0.232 g, 1.0
mmol) in dry THF (1 mL) and Pd(PPh3)4 (0.029 g, 0.025 mmol)
followed by column chromatography (silica gel, DCM/hexane 1/2
then 2/1) afforded 0.140 g of the title compound (65%) as a yellow
solid. Mp: >110 °C dec. 1H NMR (CDCl3): δ 3.13 (s, 3H, CH3), 4.04
(s, 3H, CH3), 6.83 (d, J = 8.4 Hz, 2H, CH), 7.69 (d, J = 8.4 Hz, 2H,
CH), 7.78 (d, J = 8.4 Hz, 2H, CH), 7.96 (d, J = 8.4 Hz, 2H, CH),
10.06 (s, 1H, CH). 13C NMR (CDCl3): δ 46.1, 51.3, 119.7, 127.3,
127.5, 130.2, 135.2, 136.9, 146.1, 152.3, 191.8, 217.0, 223.6, 274.2. IR
(ATR): ν 2052 (m), 1973 (w), 1871 (s), 1693 (m), 1604 (m), 1543
(m), 1488 (m), 1401 (m), 1212 (w), 1172 (w), 1118 (w), cm−1. Anal.
Calcd for C21H15CrNO6: C, 58.75; H, 3.52; N, 3.26. Found: C, 59.25;
H, 3.53, N, 2.83.
Pentacarbonyl{(N,N-dimethylamino)[5-(4-acetylphenyl)-1-
methyl-2-pyrrolyl]methylene}chromium(0) (3k). The general
procedure A starting from 1b (0.407 g, 1. 0 mmol), BuLi (0.45 mL,
1.10 mmol), ZnBr2 (0.225 g, 1.0 mmol), 4-iodoacetophenone (0.492
g, 2.0 mmol) and Pd(PPh3)4 (0.058 g, 0.05 mmol) followed by
column chromatography (silica gel, DCM/hexane 1/2 then DCM)
afforded 0.320 g of the title compound (72%) as a yellow solid. Mp:
1
>95 °C dec. H NMR (CDCl3): δ 2.62 (s, 3H, CH3), 3.17 (s, 3H,
CH3), 3.35 (s, 3H, CH3), 4.03 (s, 3H, CH3), 5.90 (d, J = 3.6 Hz, 1H,
CH), 6.35 (d, J = 3.6 Hz, 1H, CH), 7.45 (d, J = 9.0 Hz, 2H, CH), 7.98
(d, J = 9.0 Hz, 2H, CH). 13C NMR (CDCl3): δ 26.5, 32.4, 46.4, 50.5,
102.3, 110.8, 128.1, 128.6, 132.5, 135.1, 137.2, 145.1, 197.4, 216.7,
223.7, 272.6. IR (ATR): ν 2048 (m), 1891 (s), 1667 (m), 1601 (m),
1537 (w), 1444 (w), 1401 (w), 1361 (w), 1272 (w), 1183 (w), 1117
(w) cm−1. Anal. Calcd for C21H18CrN2O6: C, 56.51; H, 4.06; N, 6.28.
Found: C, 56.13; H, 4.14; N, 6.06.
Pentacarbonyl{(N,N-dimethylamino)[5-(2-pyridyl)-1-methyl-
2-pyrrolyl]methylene}chromium(0) (3l). The general procedure A
starting from 1b (0.407 g, 1. 0 mmol), BuLi (0.45 mL, 1.10 mmol),
ZnBr2 (0.225 g, 1.0 mmol), 2-bromopyridine (0.19 mL, 2.0 mmol)
and Pd(PPh3)4 (0.058 g, 0.05 mmol) followed by column
chromatography (silica gel, DCM/hexane 1/2 then DCM) afforded
0.293 g of the title compound (72%) as a yellow solid. Mp: >89 °C
dec. 1H NMR (CDCl3): δ 3.16 (s, 3H, CH3), 3.66 (s, 3H, CH3), 4.03
(s, 3H, CH3), 5.91 (d, J = 3.9 Hz, 1H, CH), 6.59 (d, J = 3.9 Hz, 1H,
CH), 7.05−7.09 (m, 1H, CH), 7.51−7.54 (m, 1H, CH), 7.61−7.67
(m, 1H, CH), 8.53−8.54 (m, 1H, CH). 13C NMR (CDCl3): δ 33.7,
46.4, 50.5, 102.4, 111.4, 120.4, 121.8, 131.3, 136.3, 145.8, 148.5, 152.5,
216.7, 223.8, 272.4. IR (ATR): ν 2049 (m), 1969 (w), 1880 (w), 1585
(w), 1532 (w), 1481 (w), 1445 (w), 1423 (w), 1399 (w), 1326 (w),
1227 (w), 1121 (w), 1071 (w) cm−1. Anal. Calcd for C18H15CrN3O5:
C, 53.34; H, 3.73; N, 10.37. Found: C, 53.33; H, 3.91; N, 10.34.
Pentacarbonyl{(N,N-dimethylamino)[5-(4-acetylphenyl)-2-
furyl]methylene}chromium(0) (3m). The general procedure A
starting from 1c (0.300 g, 1.0 mmol), BuLi (0.41 mL, 0.99 mmol),
ZnBr2 (0.171 g, 1.0 mmol), 4-iodoacetophenone (0.374 g, 1.52 mmol)
and Pd(PPh3)4 (0.044 g, 0.038 mmol) followed by column
chromatography (silica gel, DCM/hexane 1/2 then 2/1) afforded
0.210 g of the title compound (83%) as a yellow solid. Mp: >85 °C
dec. 1H NMR (CDCl3): δ 2.61 (s, 3H, CH3), 3.48 (s, 3H, CH3), 4.01
(s, 3H, CH3), 6.35 (d, J = 3.3 Hz, 1H, CH), 6.87 (d, J = 3.3 Hz, 1H,
CH), 7.80−7.84 (m, 2H, CH), 7.99−8.02 (m, 2H, CH). 13C NMR
(CDCl3): δ 26.5, 48.3, 51.7, 108.8, 109.4, 123.8, 129.0, 133.7, 136.1,
153.7, 158.8, 197.2, 217.0, 223.7, 258.5. Anal. Calcd for C20H15CrNO7:
C, 55.43; H, 3.49; N, 3.23. Found: C, 55.83; H, 3.75; N, 3.13.
Pentacarbonyl[(N,N-dimethylamino)(4′-acetyl-4-biphenyl)-
methylene]chromium(0) (5b). The general procedure A starting
from 4a (0.202 g, 0.50 mmol), BuLi (0.27 mL, 0.65 mmol), ZnBr2
(0.113 g, 0.50 mmol), 4-iodoacetophenone (0.246 g, 1.0 mmol) and
Pd(PPh3)4 (0.029 g, 0.025 mmol) followed by column chromatog-
raphy (silica gel, DCM/hexane 1/2 then 2/1) afforded 0.170 g of the
1
title compound (77%) as a yellow solid. Mp: >129 °C dec. H NMR
(CDCl3): δ 2.63 (s, 3H, CH3), 3.11 (s, 3H, CH3), 4.01 (s, 3H, CH3),
6.82 (d, J = 7.8 Hz, 2H, CH), 7.65−7.71 (m, 4H, CH), 8.02 (d, J = 7.8
F
dx.doi.org/10.1021/om500925m | Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
Hz, 2H, CH). 13C NMR (CDCl3): δ 26.6, 46.0, 51.3, 119.6, 126.8,
127.3, 128.8, 135.8, 137.0, 144.6, 152.2, 197.6, 217.0, 223.7, 274.0. IR
(ATR): ν 2054 (m), 1985 (m), 1868 (s), 1674 (s), 1601 (m), 1536
(m), 1400 (m), 1351 (m), 1274 (m), 1115 (w) cm−1. Anal. Calcd for
C22H17CrNO6: C, 59.60; H, 3.86; N, 3.16. Found: C, 59.35; H, 3.78,
N, 3.06.
Hz, 2H, CH), 7.67−7.72 (2, 4H, CH), 8.04 (d, J = 8.4 Hz, 2H, CH).
13C NMR (CDCl3): δ 26.6, 44.5, 53.7, 112.0, 126.9, 127.2, 128.9,
135.9, 137.4, 144.6, 152.6, 197.7, 198.3 (J183W−13C = 128 Hz), 203.9,
253.7. IR (ATR): ν 2060 (m), 1874 (s), 1675 (m), 1604 (w), 1544
(w), 1402 (w), 1355 (w), 1267 (w), 1122 (w), 1001 (w) cm−1. Anal.
Calcd for C22H17NO6W: C, 45.94; H, 2.98; N, 2.44. Found: C, 45.77;
H, 3.06; N, 2.33.
Pentacarbonyl[(N,N-dimethylamino)(4′-ethoxycarbonyl-4-
biphenyl)methylene]chromium(0) (5c). The general procedure A
starting from 4a (0.202 g, 0.50 mmol), BuLi (0.27 mL, 0.65 mmol),
ZnBr2 (0.113 g, 0.50 mmol), ethyl 4-iodobenzoate (0.17 mL, 1.0
mmol) and Pd(PPh3)4 (0.029 g, 0.025 mmol) followed by column
chromatography (silica gel, DCM/hexane 1/2 then 2/1) afforded
0.170 g of the title compound (72%) as a yellow solid. Alternatively,
the title compound was prepared following the general procedure B
starting from 4a (0.335 g, 0.83 mmol), iPrMgCl·LiCl (0.85 mL, 1.05
mmol), ZnBr2 (0.225 g, 1.0 mmol), ethyl 4-iodobenzoate (0.276 g, 1.0
mmol) and PdCl2XantPhos (0.031 g, 0.042 mmol) giving 0.290 g of
the 5c (74%). Mp: >117 °C dec. 1H NMR (CDCl3): δ 1.42 (t, J = 6.9
Hz, 3H, CH3), 3.12 (s, 3H, CH3), 4.03 (s, 3H, CH3), 4.41 (q, J = 6.9
Hz, 2H, CH2), 6.81 (d J = 8.1 Hz, 2H, CH), 7.65−7.69 (m, 4H, CH),
8.11 (d J = 8.1 Hz, 2H, CH). 13C NMR (CDCl3): δ 14.3, 46.0, 51.3,
60.9, 119.6, 126.6, 127.4, 129.3, 130.0, 137.2, 144.4, 152.1, 166.4,
217.1, 223.7, 274.4. IR (ATR): ν 2052 (m), 1970 (w), 1937 (m), 1878
(s), 1710 (m), 1608 (m), 1541 (m), 1402 (w), 1365 (w), 1274 (m),
1103 (m), cm−1. Anal. Calcd for C23H19CrNO7: C, 58.35; H, 4.05; N,
2.96. Found: C, 58.64; H, 4.23; N, 2.83.
Pentacarbonyl{(N,N-dimethylamino)[4-(2-pyridyl)phenyl]-
methylene}tungsten(0) (5g). The general procedure A starting
from 4b (0.536 g, 1.0 mmol), BuLi (0.40 mL, 1.30 mmol), ZnBr2
(0.225 g, 1.0 mmol), 2-bromopyridine (0.19 mL, 2.0 mmol) and
Pd(PPh3)4 (0.058 g, 0.050 mmol) followed by column chromatog-
raphy (silica gel, DCM/hexane 1/2 then DCM) afforded 0.320 g of
1
the title compound (60%) as a yellow solid. Mp: >142 °C dec. H
NMR (CDCl3): δ 3.07 (s, 3H, CH3), 3.94 (s, 3H, CH3), 6.86−6.90
(m, 2H, CH), 7.20−7.26 (m, 1H, CH), 7.73−7.76 (m, 2H, CH),
8.03−8.06 (m, 2H, CH), 8.66−8.69 (m, 1H, CH). 13C NMR
(CDCl3): δ 44.4, 53.7, 119.8, 120.3, 122.2, 127.0, 136.8, 137.2, 149.6,
153.2, 156.4, 198.3 (J183W−13C = 128 Hz), 204.0, 256.9. IR (ATR): ν
2059 (m), 1970 (m), 1866 (s), 1545 (w), 1464 (w), 1431 (w), 1402
(w), 1122 (w), 1013 (w) cm−1. Anal. Calcd for C19H14N2O5W: C,
42.72; H, 2.64; N, 5.24. Found: C, 43.08; H, 2.80; N, 5.07.
Pentacarbonyl[ethoxy(5-bromo-2-thienyl)methylene]-
chromium(0) (6a). Butyllithium (3.13 mL, 5.0 mmol, 1.6 M solution
in hexanes) was added to a solution of 2,5-dibromothiophene (1.21 g,
5.0 mmol) in dry ether (20 mL) cooled to −78 °C. The resultant
mixture was stirred for 30 min at −78 °C, then Cr(CO)6 (1.1 g, 5
mmol) was added and the mixture was stirred for 2 h at ambient
temperature. The solvents were removed under reduced pressure, and
the isolated oily residue was dissolved in water (20 mL) and cooled to
0 °C with ice−water bath. Then Et3OBF4 (1.43 g, 7.5 mmol) was
added, and the reaction mixture was stirred for 10 min at 0 °C and
precipitated red solid was isolated by extraction with ethyl acetate (3 ×
100 mL). The combined organic layers were dried (MgSO4) and
concentrated under reduced pressure, and column chromatography
(silica gel, hexane) gave 1.60 g of the title compound (78%) as a red
P e n t a c a r b o n yl (Z ) - { ( N , N - d i m e t h y l a m i n o ) [ 4 - ( 2 -
ethoxycarbonylvinyl)phenyl]methylene}chromium(0) (5d).
The general procedure A starting from 4a (0.202 g, 0.50 mmol),
BuLi (0.27 mL, 0.65 mmol), ZnBr2 (0.113 g, 0.50 mmol), (Z)-ethyl 3-
iodopropenoate (0.226 g, 1.0 mmol) and Pd(PPh3)4 (0.029 g, 0.025
mmol) followed by column chromatography (silica gel, DCM/hexane
1/2) afforded 0.150 g of the title compound (71%) as a yellow solid.
1
Mp: 77−80 °C. H NMR (CDCl3): δ 1.27 (t, J = 6.3 Hz, 3H, CH3),
3.08 (s, 3H, CH3), 4.00 (s, 3H, CH3), 4.19 (q, J = 6.3 Hz), 5.94 (d, J =
12.9 Hz, 1H, CH), 6.70 (d, J = 7.8 Hz, 2H, CH), 6.88 (d, J = 12.9 Hz,
1H, CH), 7.69 (d, J = 7.8 Hz, 2H, CH). 13C NMR (CDCl3): δ = 14.0,
46.1, 51.3, 60.3, 118.6, 119.7, 130.5, 132.3, 142.1, 152.8, 166.2, 217.0,
223.6, 274.5. IR (ATR): ν 2052 (m), 1969 (w), 1939 (m), 1871 (s),
1706 (m), 1619 (m), 1542 (m), 1502 (w), 1478 (w), 1439 (w), 1403
(m), 1178 (m) cm−1. Anal. Calcd for C19H17CrNO7: C, 53.91; H,
4.05; N, 3.31. Found: C, 53.52; H, 4.06; N, 3.10.
1
solid. Mp: 64−66 °C. H NMR (CDCl3): δ 1.65 (t, J = 7.2 Hz, 3H,
CH3), 5.14 (q, J = 7.2 Hz, 2H, CH2), 7.23 (d, J = 4.5 Hz, 1H, CH),
7.97 (d, J = 4.5 Hz, 1H, CH). 13C NMR (CDCl3): δ 15.1, 76.0, 126.6,
132.2, 141.1, 155.5, 216.8, 223.0, 314.0. IR (ATR): ν 2056 (m), 1987
(w), 1900 (s), 1399 (m), 1358 (m), 1316 (m), 1181 (m), 1108 (w),
1069 (w) cm−1. Anal. Calcd for C12H7BrCrO6S: C, 35.06; H, 1.72; S,
7.80. Found: C, 34.99; H, 1.73; S, 7.76.
Pentacarbonyl{(N,N-dimethylamino)[4-(2-pyridyl)phenyl]-
methylene}chromium(0) (5e). The general procedure A starting
from 4a (0.202 g, 0.50 mmol), BuLi (0.27 mL, 0.65 mmol), ZnBr2
(0.113 g, 0.50 mmol), 2-bromopyridine (0.095 mL, 1.0 mmol) and
Pd(PPh3)4 (0.029 g, 0.025 mmol) followed by column chromatog-
raphy (silica gel, DCM/hexane 1/2 then DCM) afforded the title
compound 0.170 g (85%) as a yellow solid. Alternatively, the title
compound was prepared following the general procedure B starting
from 4a (0.335 g, 0.83 mmol), BuLi (0.43 mL, 1.05 mmol), ZnBr2
(0.225 g, 1.0 mmol), 2-bromopyridine (0.158 g, 1.0 mmol) and
PdCl2XantPhos (0.031 g, 0.042 mmol) giving 0.173 g of the 5e (52%).
Pentacarbonyl[ethoxy(5-bromo-2-furyl)methylene]-
chromium(0) (6b). This compound was prepared according to the
modified literature procedure:19 BuLi (8.64 mL, 21.0 mmol) was
added to the solution of furane (1.45 mL, 20.0 mmol) in dry THF (40
mL) cooled to −78 °C. The resultant mixture was stirred for 1 h at 0
°C, then Cr(CO)6 (2.20 g, 10 mmol) was added, and the mixture was
stirred for another 2 h at ambient temperature. The reaction mixture
was then cooled to −78 °C and BuLi (10.70 mL, 26 mmol) was added.
After stirring for 1 h at −78 °C, C2Br2F4 (4.8 mL, 40 mmol) was
added and the mixture was allowed to warm to ambient temperature.
After 1 h, the solvents were removed under reduced pressure, and the
isolated oily residue was dissolved in water (20 mL) and cooled to 0
°C with ice−water bath. Then Et3OBF4 (5.70 g, 30.0 mmol) was
added, the reaction mixture was stirred for 10 min at 0 °C and
precipitated red solid was isolated by extraction with ethyl acetate (3 ×
100 mL). The combined organic layers were dried (MgSO4),
concentrated under reduced pressure and column chromatography
(silica gel, hexane then hexane/DCM 9/1) gave 3.50 g of the title
compound (44%) as a red solid. Mp: >59 °C dec. 1H NMR (CDCl3):
δ 1.65 (t, J = 6.9 Hz, 3H, CH3), 5.14 (q, J = 6.9 Hz, 2H, CH2), 6.54
(m, 1H, CH), 6.95 (d, J = 3.9 Hz, 1H, CH). 13C NMR (CDCl3): δ
15.2, 75.8, 115.2 (2C), 132.5, 164.9, 216.7, 223.8, 307.9. IR (ATR): ν
2059 (m), 1981 (w), 1899 (s), 1542 (w), 1418 (w), 1357 (w), 1205
(m), 1014 (w) cm−1. Anal. Calcd for C12H7BrCrO7: C, 36.48; H, 1.79.
Found: C, 36.63; H, 1.87.
1
Mp: >123 °C dec. H NMR (CDCl3): δ 3.06 (s, 3H, CH3), 3.99 (s,
3H, CH3), 6.82 (d, J = 7.8 Hz, 2H, CH), 7.20 (m, 1H, CH), 7.73 (m,
2H, CH), 8.03 (d, J = 7.8 Hz, 2H, CH), 8.67 (m, 1H, CH). 13C NMR
(CDCl3): δ 46.0, 51.3, 119.4, 120.2, 122.2, 127.1, 136.8 (2C), 149.6,
152.8, 156.4, 217.0, 223.7, 274.3. IR (ATR): ν 2050 (m), 1972 (m),
1932 (w), 1903 (s), 1868 (s), 1585 (m), 1571 (m), 1464 (m), 1431
(m), 1401 (m), 1233 (w), 1121 (w) cm−1. Anal. Calcd for
C19H14CrN2O5: C, 56.72; H, 3.51; N, 6.96. Found: C, 56.93; H,
3.58; N, 6.69.
Pentacarbonyl[(N,N-dimethylamino)(4′-acetyl-4-biphenyl)-
methylene]tungsten(0) (5f). The general procedure A starting from
4b (0.536 g, 1.0 mmol), BuLi (0.40 mL, 1.30 mmol), ZnBr2 (0.225 g,
1.0 mmol), 4-iodoacetophenone (0.492 g, 2.0 mmol) and Pd(PPh3)4
(0.058 g, 0.050 mmol) followed by column chromatography (silica gel,
DCM/hexane 1/2 then DCM) afforded 0.300 g the title compound
(52%) as a yellow solid. Mp: >150 °C dec. 1H NMR (CDCl3): δ 2.64
(s, 3H, CH3), 3.12 (s, 3H, CH3), 3.96 (s, 3H, CH3), 6.88 (d, J = 8.4
Pentacarbonyl[ethoxy(5-bromo-2-thienyl)methylene]-
tungsten(0) (6c). Butyllithium (6.25 mL, 10.0 mmol) was added to a
G
dx.doi.org/10.1021/om500925m | Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
solution of 2,5-dibromothiophene (2.42 g, 10.0 mmol) in dry ether
(40 mL) cooled to −78 °C. The resultant mixture was stirred for 30
min at −78 °C, then W(CO)6 (3.52 g, 10 mmol) was added and the
mixture was stirred for another 2 h at ambient temperature. The
solvents were removed under reduced pressure, and the isolated oily
residue was dissolved in water (20 mL) and cooled to 0 °C with ice−
water bath. Then Et3OBF4 (3.23 g, 17.0 mmol) was added, the
reaction mixture was stirred for 10 min at 0 °C, and precipitated red
solid was isolated by extraction with ethyl acetate (3 × 100 mL).
Combined organic layers were dried (MgSO4) and concentrated under
reduced pressure, and column chromatography (silica gel, hexane)
gave 4.15 g of the title compound (76%) as a red solid. Mp: 58−61 °C.
1H NMR (CDCl3): δ 1.64 (t, J = 7.2 Hz, 3H, CH3), 4.96 (q, J = 7.2
Hz, 2H, CH2), 7.22 (d, J = 4.2 Hz, 1H, CH), 7.88 (d, J = 4.2 Hz, 1H,
CH). 13C NMR (CDCl3): δ 14.9, 78.5, 127.2, 132.2, 142.1, 158.7,
197.3 (J183W−13C = 127 Hz), 202.2, 288.2. IR (ATR): ν 2065 (m), 1883
(s), 1506 (w), 1394 (m), 1314 (w), 1216 (w), 1163 (m), 1060 (w),
1015 (w) cm−1. Anal. Calcd for C12H7BrO6SW: C, 26.54; H, 1.30; S,
5.91. Found: C, 26.64; H, 1.35; S, 6.00.
Pentacarbonyl[ethoxy(5-bromo-1-methyl-2-pyrrolyl)-
methylene]chromium(0) (6d). Butyllithium (17.60 mL, 38.64
mmol) was added to a solution of 2,5-dibromo-1-methylpyrrol (9.23
g, 38.64 mmol) in dry THF (150 mL) cooled to −78 °C. The
resultant mixture was stirred for 30 min at −78 °C, then Cr(CO)6
(8.50 g, 38.64 mmol) was added and the mixture was stirred for
another 2 h at ambient temperature. The solvents were then removed
under reduced pressure, and the isolated oily residue was dissolved in
water (20 mL) and cooled to 0 °C with ice−water bath. Then
Et3OBF4 (11.0 g, 58.0 mmol) was added, the reaction mixture was
stirred for 10 min at 0 °C and precipitated red solid was isolated by
extraction with ethyl acetate (3 × 100 mL). Combined organic layers
were dried (MgSO4), concentrated under reduced pressure and
column chromatography (silica gel, hexane then hexan/DCM 4/1)
gave 6.80 g of the title compound (43%) as a red solid. Mp: >65 °C
dec.1H NMR (CDCl3): δ 1.68 (t, J = 7.2 Hz, 3H, CH3), 3.78 (s, 1H,
CH3), 5.11 (q, J = 7.2 Hz, 2H, CH2), 6.42 (m, 1H, CH), 7.67 (d, J =
4.5 Hz, 1H, CH). 13C NMR (CDCl3): δ 15.4, 38.2, 75.8, 114.5, 121.0,
133.2, 145.3, 217.6, 222.9, 302.4. IR (ATR): ν 2052 (m), 1895 (s),
1501 (w), 1468 (w), 1446 (w), 1419 (w), 1392 (w), 1361 (w), 1324
(w), 1298 (w), 1229 (w), 1194 (w), 1135 (w), 1102 (w), 1081 (w),
1043 (w), 1003 (w) cm−1. Anal. Calcd for C13H10BrCrNO6: C, 38.26;
H, 2.47; N, 3.43. Found: C, 38.53; H, 2.72; N, 3.56.
(CDCl3): δ 13.7, 15.1, 22.2, 30.4, 33.2, 75.6, 127.1, 142.5, 152.7, 158.3,
217.3, 223.2, 312.4. IR (ATR): ν 2054 (m), 1901 (s), 1431 (w), 1238
(w), 1189 (w) cm−1. Anal. Calcd for C16H16CrO6S: C, 49.48; H, 4.15;
S, 8.26. Found: C, 49.70; H, 3.90; S, 8.06.
Pentacarbonyl[ethoxy(5-phenyl-2-thienyl)methylene]-
chromium(0) (7b). The general procedure B starting from BuLi
(0.40 mL, 0.99 mmol), bromobenzene (0.095 mL, 0.90 mmol), ZnBr2
(0.203 g, 0.90 mmol), 6a (0.411 g, 1.0 mmol) and Pd(PPh3)4 (0.052 g,
0.045 mmol) followed by column chromatography (silica gel, hexane)
afforded 0.330 g of the title compound (90%) as a red solid. Mp: 104−
105 °C. 1H NMR (CDCl3): δ 1.70 (t, J = 7.2 Hz, 3H, CH3), 5.19 (q, J
= 7.2 Hz, 2H, CH2), 7.42−7.47 (m, 4H, CH), 7.70−7.73 (m, 2H,
CH), 8.27 (d, J = 4.5 Hz, 1H, CH). 13C NMR (CDCl3): δ 15.2, 75.8,
125.0, 126.4, 129.1, 129.7, 132.9, 142.6, 153.3, 153.9, 217.2, 223.3,
313.1. IR (ATR): ν 2050 (m), 1966 (w), 1894 (s), 1430 (m), 1346
(m), 1251 (m), 1179 (m), 1066 (w), 1011(w), cm−1. Anal. Calcd for
C18H12CrO6S: C, 52.94; H, 2.96; S, 7.85. Found: C, 52.70; H, 2.85; S,
7.67.
Pentacarbonyl{ethoxy[5-(6-methoxy-2-naphthyl)-2-thienyl]-
methylene}chromium(0) (7c). The general procedure B starting
from BuLi (0.40 mL, 0.99 mmol), 2-methoxy-6-bromonaphthalene
(0.213 g, 0.90 mmol), ZnBr2 (0.203 g, 0.90 mmol), 6a (0.411 g, 1.0
mmol) and Pd(PPh3)4 (0.052 g, 0.045 mmol) followed by column
chromatography (silica gel, hexane) afforded 0.440 g of the title
compound (100%) as a red solid. Mp: >131 °C dec. 1H NMR
(CDCl3): δ 1.70 (t, J = 7.2 Hz, 3H, CH3), 3.95 (s, 3H, CH3), 5.18 (q, J
= 7.2 Hz, 2H, CH2), 7.14−7.25 (m, 2H, CH), 7.55 (d, J = 4.5 Hz, 1H,
CH), 7.75 (m, 3H, CH), 8.12 (s, 1H, CH), 8.29 (d, J = 4.5 Hz, 1H,
CH). 13C NMR (CDCl3): δ 15.22, 55.3, 75.6, 105.8, 119.8, 124.3,
124.8, 125.5, 127.6, 128.0, 128.7, 129.9, 135.2, 143.0, 152.7, 154.5,
158.7, 217.2, 223.4, 311.7. IR (ATR): ν 2051 (m), 1899 (s), 1619 (m),
1479 (m), 1425 (m), 1382 (m), 1310 (w), 1234 (w), 1176 (m), 1068
(w) cm−1. Anal. Calcd for C23H16CrO7S: C, 56.56; H, 3.30; S, 6.56.
Found: C, 57.18; H, 3.20; S, 6.12.
Pentacarbonyl{ethoxy[5-(5-chloro-2-thienyl)-2-thienyl]-
methylene}chromium(0) (7d). The general procedure B starting
from BuLi (0.40 mL, 0.99 mmol), 2-chlorothiophene (0.083 mL, 0.90
mmol), ZnBr2 (0.203 g, 0.90 mmol), 6a (0.411 g, 1.0 mmol) and
Pd(PPh3)4 (0.052 g, 0.045 mmol) followed by column chromatog-
raphy (silica gel, hexane) afforded 0.300 g of the title compound
(74%) as a red solid. Mp: >140 °C dec. 1H NMR (CDCl3): δ 1.67 (t, J
= 6.9 Hz, 3H, CH3), 5.15 (q, J = 6.9 Hz, 2H, CH2), 6.90 (d, J = 4.2 Hz,
1H, CH), 7.18 (d, J = 3.9 Hz, 1H, CH), 7.22 (d, J = 3.9 Hz, 1H, CH),
8.16 (d, J = 4.2 Hz, 1H, CH). 13C NMR (CDCl3): δ 15.2, 75.8, 125.1,
125.4, 127.6, 132.1, 134.7, 142.6, 145.5, 152.3, 217.1, 223.3, 312.5. IR
(ATR): ν 2052 (m), 1893 (s), 1426 (m), 1354 (m), 1289 (m), 1235
(m), 1170 (m), 1103 (m), 1058 (m) cm−1. Anal. Calcd for
C16H9ClCrO6S2: C, 42.82; H, 2.02; S, 14.29. Found: C, 42.43; H,
2.06; S, 13.97.
Pentacarbonyl{ethoxy[5-(2-phenylethynyl)-2-thienyl]-
methylene}chromium(0) (7e). The general procedure B starting
from BuLi (0.40 mL, 0.99 mmol), phenylacetylene (0.099 mL, 0.90
mmol), ZnBr2 (0.203 g, 0.90 mmol), 6a (0.411 g, 1.0 mmol) and
Pd(PPh3)4 (0.052 g, 0.045 mmol) followed by column chromatog-
raphy (silica gel, hexane) afforded 0.240 g of the title compound
(62%) as a red oil. 1H NMR (CDCl3): δ 1.68 (t, J = 7.2 Hz, 3H, CH3),
5.17 (q, J = 7.2 Hz, 2H, CH2), 7.33 (d, J = 4.5 Hz, 1H, CH), 7.38−
7.40 (m, 3H, CH), 7.53−7.56 (m, 2H, CH), 8.15 (d, J = 4.5 Hz, 1H,
CH). 13C NMR (CDCl3): δ 15.1, 75.9, 82.4, 99.1, 122.0, 128.5, 129.3,
131.7, 132.3, 133.1, 140.6, 154.5, 216.9, 223.3, 314.4. IR (ATR): ν
2052 (s), 1894 (s), 1487 (m), 1425 (m), 1267 (w), 1211 (m), 1186
(m), 1114 (w), 1050 (w), cm−1. Anal. Calcd for C20H12CrO6S: C,
55.56; H, 2.80; S, 7.42. Found: C, 55.22, H, 2.76; S, 7.27.
Pentacarbonyl[ethoxy(5-bromo-2-furyl)methylene]-
molybdenum(0) (10). Butyllithium (5.0 mL, 12.1 mmol) was added
to a solution of 2,5-dibromothiophene (2.80 g, 11.6 mmol) in dry
THF (40 mL) cooled to −78 °C. The resultant mixture was stirred for
30 min at −78 °C, then Mo(CO)6 (3.062 g, 11.6 mmol) was added
and the mixture was stirred for another 2 h at ambient temperature.
The solvents were then removed under reduced pressure, and the
isolated oily residue was dissolved in water (20 mL) and cooled to 0
°C with ice−water bath. Then Et3OBF4 (3.31 g, 17.4 mmol) was
added, the reaction mixture was stirred for 10 min at 0 °C and
precipitated red solid was isolated by extraction with ethyl acetate (3 ×
100 mL). Combined organic layers were dried (MgSO4) and
concentrated under reduced pressure, and column chromatography
(silica gel, hexane) gave 2.69 g of the title compound (51%) as a red
1
solid. Mp: 53−55 °C. H NMR (CDCl3): δ 1.64 (t, J = 6.9 Hz, 3H,
CH3), 5.05 (q, J = 6.9 Hz, 2H, CH2), 7.34 (d, J = 4.5 Hz, 1H, CH),
7.94 (d, J = 4.5 Hz, 1H, CH). 13C NMR (CDCl3): δ 15.0, 77.7, 127.4,
132.2, 156.4, 205.8, 212.5, 304.6. Anal. Calcd for C12H7BrMoO6S: C,
31.67; H, 1.55; S, 7.05. Found: C, 32.12; H, 1.67; S, 7.47.
Pentacarbonyl[ethoxy(5-butyl-2-thienyl)methylene]-
chromium(0) (7a). The general procedure B starting from BuLi (0.21
mL, 0.50 mmol), ZnBr2 (0.113 g, 0.50 mmol), 6a (0.247 g, 0.60
mmol) and Pd(PPh3)4 (0.029 g, 0.025 mmol) followed by column
chromatography (silica gel, hexane) afforded 0.130 g of the title
Pentacarbonyl{ethoxy[5-(2-methylphenyl)-2-thienyl]-
methylene}chromium(0) (7f). The reaction mixture prepared
according the general procedure B from BuLi (0.40 mL, 0.99
mmol), 2-iodotoluene (0.196 mL, 0.90 mmol), ZnBr2 (0.203 g, 0.90
mmol), 6a (0.411 g, 1.0 mmol) and Pd(PPh3)4 (0.052 g, 0.045 mmol)
was stirred for 20 h at ambient temperature. Subsequent column
chromatography (silica gel, hexane) afforded 0.160 g of the title
1
compound (67%) as a red oil. H NMR (CDCl3): δ 0.96 (t, J = 7.2
Hz, 3H, CH3), 1.38−1.46 (m, 2H, CH2), 1.63−1.73 (m, 5H, CH2 and
CH3), 2.84 (t, J = 7.8 Hz, 2H, CH2), 5.18 (q, J = 6.9 Hz, 2H, CH2),
6.95 (d, J = 4.0 Hz, 1H, CH), 8.13 (d, J = 4.0 Hz, 1H, CH). 13C NMR
H
dx.doi.org/10.1021/om500925m | Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
compound (42%) as a red solid. Mp: 104−106 °C. 1H NMR (CDCl3):
δ 1.70 (t, J = 7.2 Hz, 3H, CH3), 2.50 (s, 3H, CH3), 5.21 (q, J = 7.2 Hz,
2H, CH2), 7.24−7.34 (m, 4H, CH), 7.45 (m, 1H, CH), 8.29 (d, J = 3.9
Hz, 1H, CH). 13C NMR (CDCl3): δ 15.2, 21.2, 75.8, 126.2, 128.6,
129.2, 130.0, 131.1, 132.8, 136.1, 141.5, 153.5, 154.1, 217.2, 223.3,
313.8. IR (ATR): ν 2055 (m), 1986 (w), 1887 (s), 1430 (m), 1358
(w), 1340 (m), 1207 (m), 1180 (m), 1072 (m), 1010 (m) cm−1. Anal.
Calcd for C19H14CrO6S: C, 54.03; H, 3.34; S, 7.59. Found: C, 54.15;
H, 3.23; S, 7.44.
Pentacarbonyl{ethoxy[5-(2-phenylethynyl)-2-furyl]-
methylene}chromium(0) (7k). The general procedure B starting
from BuLi (0.45 mL, 1.10 mmol), phenylacetylene (0.11 mL, 1.0
mmol), ZnBr2 (0.225 g, 1.0 mmol), 6b (0.435 g, 1.1 mmol) and
Pd(PPh3)4 (0.058 g, 0.05 mmol) followed by column chromatography
(silica gel, hexane then hexane/DCM 9/1) afforded 0.300 g of the title
compound (72%) as a red solid. Mp: >96 °C dec. 1H NMR (CDCl3):
δ 1.66 (t, J = 7.2 Hz, 3H, CH3), 5.16 (q, J = 7.2 Hz, 2H, CH2), 6.76 (d,
J = 3.9 Hz, 1H, CH), 7.02 (d, J = 3.9 Hz, 1H, CH), 7.39−7.41 (m, 3H,
CH), 7.57−7.61 (m, 2H, CH). 13C NMR (CDCl3): δ 15.3, 75.8, 79.1,
97.3, 113.9, 117.7, 121.3, 128.5, 129.6, 131.9, 143.5, 162.7, 216.8,
224.2, 308.6. IR (ATR): ν 2058 (m), 1985 (m), 1909 (s), 1550 (w),
1492 (w), 1460 (w), 1357 (w), 1262 (w), 1196 (w), 1151 (w), 1018
(w) cm−1. Anal. Calcd for C20H12CrO7: C, 57.70; H, 2.91. Found: C,
57.51; H, 2.99.
Pentacarbonyl[ethoxy(5-vinyl-2-thienyl)methylene]-
chromium(0) (7g). The general procedure B starting from
vinylmagnesium chloride (0.57 mL, 0.90 mmol), ZnBr2 (0.203 g,
0.90 mmol), 6a (0.411 g, 1.0 mmol) and Pd(PPh3)4 (0.052 g, 0.045
mmol) followed by column chromatography (silica gel, hexane)
1
afforded 0.220 g of the title compound (68%) as a red oil. H NMR
Pentacarbonyl[ethoxy(5-phenyl-2-thienyl)methylene]-
tungsten(0) (7l). The general procedure B starting from PhMgCl
(0.60 mL, 1.0 mmol), ZnBr2 (0.225 g, 1.0 mmol), 6c (0.597 g, 1.1
mmol) and Pd(PPh3)4 (0.058 g, 0.05 mmol) followed by column
chromatography (silica gel, hexane then hexane/DCM 4/1) afforded
0.466 g of the title compound (86%) as a red solid. Mp: >119 °C
dec.1H NMR (CDCl3): δ 1.67 (t, J = 6.6 Hz, 3H, CH3), 4.99 (q, J =
6.6 Hz, 2H, CH2), 7.42−7.46 (m, 4H, CH), 7.70−7.72 (m, 2H, CH),
8.15−8.17 (m, 1H, CH). 13C NMR (CDCl3): δ 15.0, 78.2, 125.0,
126.3, 129.2, 129.7, 133.1, 143.4, 155.0, 156.3, 197.7 (J183W‑13C = 127
Hz), 202.5, 287.7. IR (ATR): ν 2058 (s), 1963 (w), 1882 (s), 1520
(w), 1429 (m), 1346 (w), 1249 (m), 1180 (m), 1109 (w), 1063 (w),
1011 (w) cm−1. Anal. Calcd for C18H12O6SW: C, 40.02; H, 2.24; S,
5.94. Found: C, 40.19; H, 2.27; S, 5.96.
Pentacarbonyl{ethoxy[5-(2-phenylethynyl)-2-thienyl]-
methylene}tungsten(0) (7m). The general procedure B starting
from BuLi (0.45 mL, 1.10 mmol), phenylacetylene (0.11 mL, 1.0
mmol), ZnBr2 (0.225 g, 1.0 mmol), 6c (0.597 g, 1.1 mmol) and
Pd(PPh3)4 (0.058 g, 0.05 mmol) followed by column chromatography
(silica gel, hexane then hexane/DCM 4/1) afforded 0.285 g of the title
compound (51%) as a red solid. Mp: 79−81 °C. 1H NMR (CDCl3): δ
1.66 (t, J = 7.2 Hz, 3H, CH3), 4.98 (q, J = 7.2 Hz, 2H, CH2), 7.30−
7.38 (m, 4H, CH), 7.53−7.56 (m, 2H, CH), 8.04−8.05 (m, 1H, CH).
13C NMR (CDCl3): δ 14.9, 78.4, 82.8, 99.2, 122.0, 128.5, 129.4, 131.6,
133.0, 133.4, 141.1, 157.8, 197.4 (J183W‑13C = 127 Hz), 202.4, 288.5. IR
(ATR): ν 2064 (m), 1975 (w), 1889 (s), 1481 (w), 1414 (m), 1344
(w), 1256 (w), 1191 (m), 1159 (m), 1108 (w), 1015 (w) cm−1. Anal.
Calcd for C20H12O6SW: C, 42.58; H, 2.14; S, 5.68. Found: C, 42.79;
H, 2.24; S, 5.66.
Pentacarbonyl{ethoxy[5-phenyl-2-thienyl]methylene}-
molybdenum(0) (12a). The general procedure B starting from BuLi
(0.45 mL, 1.10 mmol), bromobenzene (0.157 g, 1.0 mmol), ZnBr2
(0.225 g, 1.0 mmol), 10 (0.500 g, 1.1 mmol) and Pd(PPh3)4 (0.058 g,
0.05 mmol) followed by column chromatography (silica gel, hexane)
afforded 0.350 g of the title compound (77%) as a red solid. Mp: >81
°C dec. 1H NMR (CDCl3): δ 1.66 (t, J = 6.9 Hz, 3H, CH3), 5.06 (q, J
= 6.9 Hz, 2H, CH2), 7.41−7.46 (m, 4H, CH), 7.69−7.72 (m, 2H,
CH), 8.19 (d, J = 4.5 Hz, 1H, CH). 13C NMR (CDCl3): δ 15.1, 77.5,
124.9, 126.3, 129.2, 129.7, 133.0, 143.3, 154.0, 155.0, 206.2, 212.9,
303.7. Anal. Calcd for C18H12MoO6S: C, 47.80; H, 2.67; S, 7.09.
Found: C, 48.13; H, 2.85; S, 7.57.
(CDCl3): δ 1.66 (t, J = 7.2 Hz, 3H, CH3), 5.16 (q, J = 7.2 Hz. 2H,
CH2), 5.41 (d, J = 10.8 Hz, 1H, CH), 5.88 (d, J = 17.1 Hz, 1H, CH),
6.78 (dd, J = 10.8, 17.4 Hz, 1H, CH), 7.12 (d, J = 4.5 Hz, 1H, CH),
8.15 (d, J = 4.5 Hz, 1H, CH). 13C NMR (CDCl3): δ 15.2, 75.8, 118.4,
127.4, 129.5, 142.1, 151.7, 152.7, 217.1, 223.3, 313.8. IR (ATR): ν
2054 (w), 1890 (s), 1433 (w), 1181 (w), 1057 (w), 1010 (w) cm−1.
Anal. Calcd for C14H10CrO6S: C, 46.93; H, 2.81; S, 8.95. Found: C,
46.59; H, 2.80; S, 8.62.
Pentacarbonyl{ethoxy[4-(ethoxycarbonylphenyl)-2-thienyl]-
methylene}chromium(0) (7h). The general procedure B starting
from iPrMgCl·LiCl (0.77 mL, 0.95 mmol), ethyl 4-iodobenzoate
(0.248 g, 0.90 mmol), ZnBr2 (0.203 g, 0.90 mmol), 6a (0.411 g, 1.0
mmol) and Pd(PPh3)4 (0.052 g, 0.045 mmol) followed by column
chromatography (silica gel, hexane/DCM, 4/1 then 1/1) afforded
0.220 g of the title compound (51%) as a red solid. Mp: >123 °C dec.
1H NMR (CDCl3): δ 1.41 (t, J = 6.9 Hz, 3H, CH3), 1.70 (t, J = 6.9 Hz,
3H, CH3), 4.40 (q, J = 6.9 Hz, 2H, CH3), 5.19 (q, J = 6.9 Hz, 3H,
CH3), 7.53 (d, J = 4.5 Hz, 1H, CH), 7.75 (d, J = 8.4 Hz, 2H, CH),
8.09 (d, J = 8.4 Hz, 2H, CH), 8.25 (d, J = 4.2 Hz, 1H, CH). 13C NMR
(CDCl3): δ 14.3, 15.2, 61.2, 75.9, 125.95, 126.04, 130.3, 131.0, 137.0,
142.1, 151.6, 154.2, 165.8, 217.0, 223.3, 314.4. IR (ATR): ν 2052 (m),
1897 (s), 1703 (m), 1604 (w), 1425 (w), 1361 (w), 1271 (w), 1245
(w), 1174 (w), 1105 (w), 1011(w) cm−1. Anal. Calcd for
C21H16CrO8S: C, 52.50; H, 3.36; S, 6.67. Found: C, 52.38; H, 3.25;
S, 6.74.
Pentacarbonyl{ethoxy[5-(4′-carbonitrile-4-biphenyl)-2-
thienyl]methylene}chromium(0) (7i). The general procedure B
starting from iPrMgCl·LiCl (0.77 mL, 0.95 mmol), 4′-iodobiphenyl-4-
carbonitrile (0.275 g, 0.90 mmol), ZnBr2 (0.203 g, 0.90 mmol), 6a
(0.411 g, 1.0 mmol) and Pd(PPh3)4 (0.052 g, 0.045 mmol) followed
by column chromatography (silica gel, hexane/DCM 4/1 then 1/1)
afforded 0.350 g of the title compound (76%) as a red solid. Mp: >155
°C dec. 1H NMR (CDCl3): δ 1.70 (t, J = 7.2 Hz, 3H, CH3), 5.19 (q, J
= 7.2 Hz, 2H, CH2), 7.52 (d, J = 4.5 Hz, 1H, CH), 7.65−7.83 (m, 8H,
CH), 8.26 (d, J = 4.5 Hz, 1H). 13C NMR (125.8 MHz, THF-d6): δ
15.3, 77.3, 112.6, 118.9, 126.6, 127.7, 128.3, 128.7, 133.4, 134.0, 141.1,
144.0, 144.8, 154.0, 154.4, 218.1, 224.4, 313.6. IR (ATR): ν 2225 (w),
1893 (s), 1606 (m), 1431 (m), 1353 (w), 1252 (w), 1174 (m), 1068
(m), 1003 (w) cm−1. Anal. Calcd for C25H15CrO6S: C, 58.94; H, 2.97;
N, 2.75; S, 6.29. Found: C, 58.67; H, 2.86; N, 2.62; S, 6.18.
Pentacarbonyl[ethoxy(5-phenyl-2-furyl)methylene]-
chromium(0) (7j). The general procedure B starting from phenyl-
magnesium chloride (0.60 mL, 1.0 mmol), ZnBr2 (0.225 g, 1.0 mmol),
6b (0.435 g, 1.1 mmol) and Pd(PPh3)4 (0.058 g, 0.05 mmol) followed
by column chromatography (silica gel, hexane then hexane/DCM 9/
1) afforded 0.370 g of the title compound (94%) as a red solid. Mp:
>131 °C dec. 1H NMR (CDCl3): δ 1.65 (t, J = 7.2 Hz, 3H, CH3), 5.14
(q, J = 7.2 Hz, 2H, CH2), 6.85 (d, J = 3.6 Hz, 1H, CH), 7.03 (d, J = 3.6
Hz, 1H, CH), 7.42−7.52 (m, 3H, CH), 7.90−7.94 (m, 2H, CH). 13C
NMR (CDCl3): δ 15.3, 75.4, 108.4, 113.2, 125.1, 129.07, 129.12,
129.9, 162.2, 163.3, 217.2, 224.1, 306.6. IR (ATR): ν 2052 (m), 1902
(s), 1555 (w), 1500 (w), 1448 (w), 1376 (w), 1188 (w), 1111 (w),
1068 (w), 1013 (w) cm−1. Anal. Calcd for C18H12CrO7: C, 55.11; H,
3.08. Found: C, 55.00; H, 3.17.
Pentacarbonyl{ethoxy[5-(2-phenylethynyl)-2-thienyl]-
methylene}molybdenum(0) (12b). The general procedure B
starting from BuLi (0.45 mL, 1.10 mmol), phenylacetylene (0.11
mL, 1.0 mmol), ZnBr2 (0.225 g, 1.0 mmol), 10 (0.597 g, 1.1 mmol)
and Pd(PPh3)4 (0.058 g, 0.05 mmol) followed by column
chromatography (silica gel, hexane) afforded 0.370 g of the title
1
compound (78%) as a red wax. H NMR (CDCl3): δ 1.67 (t, J = 6.9
Hz, 3H, CH3), 5.07 (q, J = 6.9 Hz, 2H, CH2), 7.33 (d, J = 4.2 Hz, 1H,
CH), 7.39−7.41 (m, 3H, CH), 7.55−7.59 (m, 2H, CH), 8.11 (d, J =
4.2 Hz, 1H, CH). Anal. Calcd for C20H12MoO6S: C, 50.43; H, 2.54; S,
6.73. Found: C, 50.66; H, 2.70; S, 7.02.
Pentacarbonyl{(N,N-dimethylamino)(2-thienyl)methylene}-
molybdenum(0) (9). Butyllithium (8.2 mL, 20.0 mmol) was added
to a solution of thiophene (1.60 g, 20.0 mmol) in dry THF (40 mL)
I
dx.doi.org/10.1021/om500925m | Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
cooled to −78 °C. The resultant mixture was stirred for 30 min at 0
°C, then Mo(CO)6 (5.28 g, 20.0 mmol) was added and the mixture
was stirred for another 2 h at ambient temperature. The solvents were
then removed under reduced pressure, and the isolated oily residue
was dissolved in water (40 mL) and cooled to 0 °C with ice−water
bath. Then Et3OBF4 (5.70 g, 30.0 mmol) was added, the reaction
mixture was stirred for 10 min at 0 °C, and precipitated red solid was
isolated by extraction with ethyl acetate (3 × 100 mL). Combined
organic layers were dried (MgSO4), dry solution of the alkoxycarbene
was mixed with dimethylamine (20 mL, 40 mmol, 2 M solution in
ether), and the resultant mixture was stirred 2 h at ambient
temperature. Then the solvents were removed under reduced pressure
and column chromatography (silica gel, DCM/hexane 1/4 then 1/2)
gave 4.56 g of the title compound (61%) as a yellow solid. Mp: >81 °C
dec. 1H NMR (CDCl3): δ 3.23 (s, 3H, CH3), 3.95 (s, 3H, CH3), 6.54
(dd, J = 1.2, 3.6 Hz, 1H, CH), 6.99 (dd, J = 3.6, 3.9 Hz, 1H, CH), 7.31
(dd, J = 1.2, 3.9 Hz, 1H, CH). 13C NMR (CDCl3): δ 45.1, 53.0, 118.6,
124.3, 126.9, 153.0, 205.9, 214.4, 262.5. Anal. Calcd for
C12H9CrNO5S: C, 38.41; H, 2.42; N, 3.73; S, 8.55. Found: C,
38.86; H, 2.53; N, 3.81; S, 8.80.
Pentacarbonyl{(N,N-dimethylamino)[5-(4-acetylphenyl)-2-
thienyl]methylene}molybdenum(0) (11a). The general procedure
A starting from 9 (0.375 g, 1.0 mmol), BuLi (0.53 mL, 1.3 mmol),
ZnBr2 (0.225 g, 1.0 mmol), 4-iodoacetophenone (0.492 g, 2.0 mmol)
and Pd(PPh3)4 (0.058 g, 0.05 mmol) followed by column
chromatography (silica gel, DCM/hexane 1/2 then 2/1) afforded
0.280 g of the title compound (57%) as a yellow solid. Mp: >89 °C
dec. 1H NMR (CDCl3): δ 2.61 (s, 3H, CH3), 3.32 (s, 3H, CH3), 3.98
(s, 3H, CH3), 6.55 (d, J = 3.9 Hz, 1H, CH), 7.32 (d, J = 3.9 Hz, 1H,
CH), 7.65 (d, J = 8.7 Hz, 2H, CH), 7.97 (d, J = 8.7 Hz, 2H, CH). 13C
NMR (CDCl3): δ 26.5, 45.3, 52.9, 119.9, 124.5, 125.2, 129.1, 135.8,
137.9, 141.8, 153.3, 197.2, 205.8, 214.0, 261.5. Anal. Calcd for
C20H15MoNO6S: C, 48.69; H, 3.06; N, 2.84; S, 6.50. Found: C, 48.97;
H, 3.55; N, 2.56; S, 6.50.
REFERENCES
■
(1) (a) Dotz, K. H.; Stendel, J. Chem. Rev. 2009, 109, 3227.
̈
(b) Santamaría, J. Curr. Org. Chem. 2009, 13, 31. (c) Wu, Y.-T.;
Kurahashi, T.; De Meijere, A. J. Organomet. Chem. 2005, 690, 5900.
́
́
(d) Fernandez-Rodríguez, M. A.; García-García, P.; Aguilar, E. Chem.
Commun. 2010, 46, 7670.
(2) (a) Hegedus, L. S. Metal Carbenes in Organic Synthesis; Topics in
Organometallic Chemistry; Springer: Berlin, Heidelberg, 2004; Vol.
13, pp 157−201. (b) Fernan
Chem. Res. 2011, 44, 479.
(3) (a) Barluenga, J.; Lop
Granda, S.; Alvarez-Rua, C.; Borge, J. Angew. Chem., Int. Ed. 2001, 40,
́
dez, I.; Cossío, F. P.; Sierra, M. A. Acc.
́
́
ez, L. A.; Lober, O.; Tomas, M.; García-
̈
́
3392. (b) Barluenga, J.; Barrio, P.; Vicente, R.; Lop
M. J. Organomet. Chem. 2004, 689, 3793. (c) del Amo, J. C.;
́ ́
ez, L. A.; Tomas,
Mancheno, M. J.; Gom
́
ez-Gallego, M.; Sierra, M. A. Organometallics
̃
2004, 23, 5021.
(4) Fananas
́
-Mastral, M.; Aznar, F. Organometallics 2009, 28, 666.
(5) (a) Kamikawa, K.; Shimizu, Y.; Takemoto, S.; Matsuzaka, H. Org.
Lett. 2006, 8, 4011. (b) Barluenga, J.; Barrio, P.; Riesgo, L.; Lopez, L.
A.; Tomas, M. Tetrahedron 2006, 62, 7547. (c) Barluenga, J.; Barrio,
P.; Riesgo, L.; Lopez, L. A.; Tomas, M. J. Am. Chem. Soc. 2007, 129,
14422.
(6) (a) Barluenga, J.; Vicente, R.; Barrio, P.; Lop
Borge, J. J. Am. Chem. Soc. 2004, 126, 14354. (b) Barluenga, J.;
Vicente, R.; Barrio, P.; Lopez, L. A.; Tomas, M. J. Am. Chem. Soc. 2004,
126, 5974.
̃
́
́
́
́
́
́
ez, L. A.; Tomas, M.;
́
́
(7) (a) Faux, N.; Guen, F. R. L.; Poul, P. L.; Caro, B.; Poul, N. L.;
Mest, Y. L.; Green, S. J.; Roux, S. L.; Kahlal, S.; Saillard, J. Y.
Tetrahedron 2007, 63, 7142. (b) Lage, M. L.; Curiel, D.; Fernan
Mancheno, M. J.; Gomez-Gallego, M.; Molina, P.; Sierra, M. A.
Organometallics 2011, 30, 1794. (c) Chu, G. M.; Fernandez, I.; Sierra,
M. A. J. Org. Chem. 2013, 78, 865. (d) Sierra, M. A.; Mancheno, M. J.;
́
dez, I.;
́
̃
́
̃
Sae
́
z, E.; del Amo, J. C. J. Am. Chem. Soc. 1998, 120, 6812.
(8) (a) Sierra, M. A.; del Amo, J. C.; Mancheno, M. J.; Gom
́
ez-
dez, I.;
̃
Pentacarbonyl{(N,N-dimethylamino)[5-(4-formylphenyl)-2-
thienyl]methylene}molybdenum(0) (11b). The general procedure
A starting from 9 (0.375 g, 1.0 mmol), BuLi (0.53 mL, 1.3 mmol),
ZnBr2 (0.225 g, 1.0 mmol), 4-benzaldehyde (0.464 g, 2.0 mmol) and
Pd(PPh3)4 (0.058 g, 0.05 mmol) followed by column chromatography
(silica gel, DCM/hexane 1/2 then 2/1) afforded 0.256 g of the title
compound (53%) as a yellow solid. Mp: >90 °C dec. 1H NMR
(CDCl3): δ 3.31 (s, 3H, CH3), 3.96 (s, 3H, CH3), 6.55 (d, J = 3.3 Hz,
1H, CH), 7.35 (d, J = 3.3 Hz, 1H, CH), 7.69 (d, J = 8.7 Hz, 2H, CH),
7.86 (d, J = 8.7 Hz, 2H, CH), 9.97 (s, 1H, CH). 13C NMR (CDCl3): δ
45.3, 52.9, 119.9, 124.9, 125.6, 130.4, 135.1, 139.2, 141.5, 153.7, 191.3,
205.7, 214.0, 261.1. Anal. Calcd for C19H13MoNO6S: C, 47.41; H,
2.73; N, 2.92; S, 6.69. Found: C, 48.03; H, 3.10; N, 2.72; S, 6.92.
Gallego, M. J. Am. Chem. Soc. 2001, 123, 851. (b) Fernan
Mancheno, M. J.; Vicente, R.; Lop
́
́
ez, L. A.; Sierra, M. A. Chem.Eur.
ez-Alberca, M. P.; Fernandez, I.;
ez-Gallego, M.; Casarrubios, L.; Sierra, M. A.
Eur. J. Org. Chem. 2011, 3293. (d) Lopez-Alberca, M. P.; Mancheno,
̃
J. 2008, 14, 11222. (c) Lop
́
́
Mancheno, M. J.; Gom
́
̃
́
̃
M. J.; Fernan
Lett. 2007, 9, 1757.
(9) (a) Barluenga, J.; Vicente, R.; Lop
́ ́
dez, I.; Gomez-Gallego, M.; Sierra, M. A.; Torres, R. Org.
́
ez, L. A.; Rubio, E.; Tomas
́
, M.;
́
Alvarez-Rua, C. J. Am. Chem. Soc. 2004, 126, 470. (b) Barluenga, J.;
́
Vicente, R.; Lop
(c) Barluenga, J.; Vicente, R.; Lop
Organomet. Chem. 2006, 691, 5642. (d) Barluenga, J.; Vicente, R.;
Lopez, L. A.; Tomas, M. J. Am. Chem. Soc. 2006, 128, 7050.
́
ez, L. A.; Tomas
́
, M. Tetrahedron 2005, 61, 11327.
́
ez, L. A.; Rubio, E.; Tomas, M. J.
́
́
́
(10) (a) Gottker-Schnetmann, I.; Aumann, R.; Bergander, K.
Organometallics 2001, 20, 3574. (b) Barluenga, J.; Vicente, R.;
̈
ASSOCIATED CONTENT
■
Lopez, L. A.; Tomas, M. Tetrahedron 2010, 66, 6335. (c) Gottker-
́
́
̈
S
Schnetmann, I.; Aumann, R. Organometallics 2001, 20, 346.
(11) (a) Hazra, D.; Sarkar, A. Indian J. Chem., Sect. A 2003, 42a,
2398. (b) Ganesamoorthi, R.; Thakur, A.; Sharmila, D.; Ramkumar, V.;
Ghosh, S. J. Organomet. Chem. 2013, 726, 56.
* Supporting Information
1H and 13C NMR spectra copies. This material is available free
of charge via the Internet at http://pubs.acs.org.
(12) Lop
Gallego, M.; Sierra, M. A. Org. Lett. 2008, 10, 365.
(13) (a) Baeza, B.; Casarrubios, L.; Ramírez-Lop
Gallego, M.; Sierra, M. A. Organometallics 2009, 28, 956.
(b) Casarrubios, L.; de la Torre, M. C.; Sierra, M. A. Chem.Eur. J.
2013, 19, 3534. (c) Baeza, B.; Casarrubios, L.; Sierra, M. A. Chem.
Eur. J. 2013, 19, 1429.
́
ez-Alberca, M. P.; Mancheno, M. J.; Fernan
́
dez, I.; Gom
́
ez-
̃
AUTHOR INFORMATION
■
́
ez, P.; Gom
́
ez-
Corresponding Author
*E-mail: dvorakd@vscht.cz.
Notes
The authors declare no competing financial interest.
(14) Hartbaum, C.; Mauz, E.; Roth, G.; Weissenbach, K.; Fischer, H.
Organometallics 1999, 18, 2619.
(15) Drahon
43, 7867.
(16) Tobrman, T.; Juras
metallics 2014, 33, 2990.
(17) Krasovskiy, A.; Knochel, P. Angew. Chem., Int. Ed. 2004, 43,
3333.
̌
ovsky, D.; Borgo, V.; Dvora
̌
k
́
, D. Tetrahedron Lett. 2002,
́
ACKNOWLEDGMENTS
■
This project was supported by the Research Centre “The
Structure and Synthetic Applications of Transition Metal
Complexes−LC06070” of the Ministry of Education, Youth
and Sports of the Czech Republic.
́
kova,
́
I.; Van
́
̌
ova, H.; Dvora , D. Organo-
́
̌ ́
k
J
dx.doi.org/10.1021/om500925m | Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
(18) Metelkova,
Ludvík, J. Electrochim. Acta 2012, 82, 470.
́ ́ ́
R.; Tobrman, T.; Kvapilova, H.; Hoskovcova, I.;
(19) Aoki, S.; Fujimura, T.; Nakamura, E. J. Am. Chem. Soc. 1992,
114, 2985.
K
dx.doi.org/10.1021/om500925m | Organometallics XXXX, XXX, XXX−XXX