Iron-catalyzed carbonylation of aryl halides with arylborons using stoichiometric chloroform as the carbon monoxide source

Article abstract of DOI:10.1039/c6gc02158a

A general iron-catalyzed carbonylative Suzuki-Miyaura coupling of aryl halides with arylborons is reported, using stoichiometric CHCl₃ as the CO source. The high efficiency, economy, selectivity, and operational simplicity of this transformation make this method a valuable tool in organic synthesis. Importantly, the presented strategy allows effective ¹³C labeling simply by using the commercially available ¹³C-labeled CHCl₃. On the basis of the initial mechanistic exploration, an aryl radical intermediate is proposed in the present carbonylation process.

Full text of DOI:10.1039/c6gc02158a

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Iron-Catalyzed Carbonylation of Aryl halides with Arylborons Using
View Article Online
DOI: 10.1039/C6GC02158A
‡
Stoichiometric Chloroform as the Carbon Monoxide Source
a
a
a
a
Hongyuan Zhao, † Hongyan Du, † Xiaorong Yuan, Tianjiao Wang and Wei Han*
Received (in XXX, XXX) Xth XXXXXXXXX 200X, Accepted Xth XXXXXXXXX 200X
First published on the web Xth XXXXXXXXX 200X
DOI: 10.1039/b000000x
5
A general iron-catalyzed carbonylative Suzuki-Miyaura coupling
of aryl halides with arylborons is reported, using stoichiometric
surrogate having advantages in operational simplicity,
economic viability, and high stability toward air and water for
CHCl3 as the CO source. The high efficiency, economy, 55 carbonylative Suzuki-Miyaura coupling.
Recently, chloroform (CHCl ) has received attention as a
widely available, stable, and inexpensive substitute for CO
1
0
selectivity, and operational simplicity of this transformation
render this method a valuable tool in organic synthesis.
3
[
8]
13
and has been successfully employed in carboxylation,
Importantly, the presented strategy allows effective C labeling
[
9]
13
aminocarbonylation,
coupling.
and
The release of CO can be achieved through
hydrolysis of CHCl3 in the presence of strongly basic
carbonylative
Sonogashira
simply by using the commercially available C-labeled CHCl3.
On the basis of initial mechanistic exploration, an aryl radical
intermediate is proposed in the present carbonylation process.
[
10]
6
6
7
7
8
8
0
5
0
5
0
5
1
5
[
8-11]
hydroxides (often with 10 equiv of hydroxide).
Although
chloroform as a CO source shows superior properties over CO
gas and all of the above-mentioned CO surrogates, expansion
of this CO source to carbonylative Suzuki-Miyaura coupling
is an unmet challenge since several undesirable side reactions,
Transition-metal-catalyzed carbonylation utilizing CO gas,
known as C1 chemistry, is
a
fundamental chemical
transformation for the construction of carbonyl compounds
and their derivatives, and has become an industrial core
[
12]
[13]
[
1]
such
noncarbonylative
homocoupling,
as
hydroxylation,
hydroxycarbonylation,
2
2
3
3
4
4
5
0
5
0
5
0
5
0
technology. Carbonylative Suzuki-Miyaura reaction is one
of the most important transition-metal-catalyzed
[
14]
Suzuki-Miyaura
and dehalogenation
coupling,
can proceed
[
15]
[15]
carbonylations, as it possesses unique features, such as readily
accessible and stable substrates, high regio- and
stereoselectivity, broad substrate scope, and wide functional
simultaneously in the presence of palladiun catalyst and a
large excess of hydroxide base (8−10 equiv).
[
1e, 2]
While remarkable advances in the development of CO
surrogates have been achieved, in all cases these
transformations have to use palladium-phosphine catalysts
group compatibility.
Not surprisingly, the reaction has
become one of the most straightforward and practical
processes for the synthesis of an array of unsymmetrical and
symmetrical biaryl ketones, which are omnipresent in
pharmaceuticals, natural products, photosensitizers, and
-
6
with limited availability (1 x 10 wt% in the earth crust of
palladium), high cost, significant toxicity, and poor stability.
These drawbacks hinder the transfer of the advancements to
large-scale applications. Therefore, the development of more
economical and environmentally benign catalysts for the
aforementioned transformation is of considerable importance.
In this respect, it is more desirable to investigate catalysts
based on first-row transition metals, such as iron, copper, zinc,
and nickel. Especially iron is an ideal candidate for catalysis,
since it is widely distributed in nature, the second most
abundant metal in the earth crust (4.7 wt%), and ecological
[
3]
advanced organic materials.
Despite a powerful method, gaseous CO is toxic, flammable,
odorless, and awkward to handle (mainly at high pressure),
and consequently leads to severely limit the application of this
[
4]
protocol. To address this issue, few precursors that can act
as CO surrogates have been reported in the carbonylative
Suzuki-Miyaura reaction. Early in 2011 Jafarpour et al.
reported the first carbonylative Suzuki-Miyaura coupling of
aryl iodides using Mo(CO) as the carbon monoxide source,
6
[
16]
friendly.
Despite these advantages, until recently, iron-
albeit with a high palladium catalyst loading (10 mol%) and a
o
[5]
based catalytic carbonylation is far underexplored and
high temperature (140 C). More recently, 9-methyl-9H-
fluorene-9-carbonyl chloride, a significent CO precursor, was
succesfully employed in the transformation and readily
[
17]
generally requires high pressure of CO.
Pioneerring studies
on iron catalyzed carbonylation of aryl iodides reported by
[
6]
90 Brunet group used Co (CO) as a co-catalyst to deliver
produced carbon-13 and carbon-14 labeled benzophenones.
2
8
18]
[
symmetrical biaryl ketones.
However, these contributions
However, an extra high palladium/phospine catalyst loading
(5 mol%) is required to liberate CO and the necessity of a
special equipment would reduce the applicability of this
protocol. Later, acetic formic anhydride, in situ generated
from the reaction of formic acid and acetic anhydride, was
utilized as a suitable CO source for carbonylative Suzuki-
are impractical to organic synthesis due to narrow scope of
substrates, poor chemoselectivity, and low functional group
compatibility. Recently, we reported a general and selective
iron-catalyzed carbonylative Suzuki-Miyaura reactions of aryl
iodides with arylboronic acids under atmospheric pressure of
9
5
[
19]
[
7]
CO.
While this finding represents a breakthrough in iron-
Miyaura coupling,
but sensitive to moisture and active
catalyzed carbonylation of aryl halides, the intrinsic
drawbacks of CO gas undermine the attractiveness of the
groups, thereby leading to the limitation of the potential
substrate scope. Therefore, it is significent to seek a CO
This journal is © The Royal Society of Chemistry [year]
Journal Name, [year], [vol], 00–00 | 1

Green Chemistry
Page 2 of 6
method. To date, iron-catalyzed carbonylative coupling of aryl
halide using CO surrogate has gone undiscovered. Here, we
develop an iron system capable of carbonylating a wide range
of aryl halides with aryltrifluoroborates and arylboronic acids
leads to the complete formation of side product 3a’a’ (entries 1-
View Article Online
2). To our delight, switching to 10 mol% of FeCl gave 5% of the
2
DOI: 10.1039/C6GC02158A
desire product 3aa with excellent selectivity (entry 3) and a 15 %
yield was observed with less PPh (entry 4). In the absence of
3
5
0
5
using stoichiometric amounts of CO generated in situ from 25 FeCl 3aa was not detected (entry 5). Further, without PPh a
2 3
stable and inexpensive chloroform. Notably, this protocol
70 % yield of 3aa was obtained at elevated temperature, albeit
with 16% of 3a’a’ (entry 6). When the additive PivOH was not
added, the yield of product 3aa decreased from 70% to 50%,
1
3
allows effective C labeling.
Encouraged by our recent studies on carbonylation
[
19-20]
[
21]
where the performance of the catalytic systems based on PEG-
400 is highly desirable, we started our investigation by 30 contrast, by using 1.5 equiv of PivOH, a far superior result was
accompanying the yield increase of 3a’a’ (38%) (entry 7). In
1
examining FeCl -catalyzed trimodular carbonylative cross-
obtained (entry 8) (for details see the ESI, Table S1). Other acids
such as AcOH, TFA, and 9-anthroic acid were also examined and
found to be much less effective (entries 9-11). Na CO appeared
2
coupling of 1-chloro-4-iodobenzene (1a), potassium phenyl
trifluoroborate (2a), and chloroform with Na CO as base and
2
3
2
3
[
21]
PivOH
as additive in PEG-400 (Table 1). While the
to be the choice of base after the common bases had been tested,
1
combination of palladium-phosphine has been the most 35 e.g., Li CO3 (75%), K CO3 (30%), Cs CO3 (10%), NaHCO3
2
2
2
common catalyst used in carbonylation of aryl halides, it
doesn’t work for the desired carbonylation reaction at all and
(54%), Na PO (65%), K PO (40%), Na HPO (40%), NaF (5%),
3 4 3 4 2 4
AcONa (0), and DBU (0) (entries 12-21). Considering a
hydroxide base playing a critical role in rapidly hydrolyzing
Table 1 Iron-catalyzed carbonylative Suzuki-Miyaura reaction of 1a with
[8-11]
CHCl to CO,
We also briefly screened hydroxide bases and
a
3
2
a.
.
40
chloroform equivalencies, and found that CsOH H O was the best
2
hydroxide base and 3.0 equiv of chloroform was the best quantity
(for details see the ESI, Tables S2 and S3). We then surveyed
other solvents and observed that 3aa was provided in 0–45%
yields (entries 22-26). Previous reports indicated that iodide
additive could promote carbonylative Suzuki-Miyaura
2
0
Ent
ry
[Cat]
Base
Additive
Solvent
Yield
3aa%
Yield
3a’a’%
45
[
14]
b,c
coupling. Indeed, 0.5 equiv of NaI further raised the yield of
aa (87%) and suppressed the formation of 3a’a’ (5%) (entry 27)
1
,
d,e
b,c
Pd(OAc)
2
Na
Na
Na
Na
Na
2
2
2
2
2
CO
CO
CO
CO
CO
3
3
3
3
3
PivOH
PivOH
PivOH
PivOH
PivOH
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
0
0
99
99
0
3
2
,
d,e
c,d
PdCl
FeCl
FeCl
-
2
2
2
(for details see the ESI, Table S4). Additionally, other iron salts
were screened and resulted in 50-77% yields of 3aa (for details
3,
e
5
c,d
50 see the ESI, Table S5). The use of ultrapure FeCl
2
(99.99% based
(99.997% based
3
4,
f
15
0
2
on trace metals, Alfa Aesar), ultrapure Na CO
2
c,d
5,
f
0
on trace metals, Alfa Aesar), and ultrapure NaI (99.999% based
on trace metals, Acros) resulted in a slightly better yield of 3aa
6
7
8
9
FeCl
FeCl
FeCl
FeCl
FeCl
2
2
2
2
2
Na
Na
Na
Na
Na
2
2
2
2
2
CO
CO
CO
CO
CO
3
3
3
3
3
PivOH
-
PivOH
AcOH
TFA
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
70
50
84
57
40
16
38
8
20
10
(entry 28). Moreover, inductively coupled plasma atomic
5
5
emission spectroscopy (ICP–AES) assay of the reaction system
under standard conditions confirmed that the concentrations of
transition metals, such as Pd, Cu, and Ni were below the
detection limit of the machine. These results suggest that the
present catalytic system is based on iron.
1
0
9
-An
1
1
FeCl
2
Na
2
CO
3
PEG-400
18
12
acid
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
FeCl
FeCl
FeCl
FeCl
FeCl
FeCl
FeCl
FeCl
FeCl
FeCl
FeCl
FeCl
FeCl
FeCl
FeCl
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Li
2
CO
CO
CO
3
PivOH
PivOH
PivOH
PivOH
PivOH
PivOH
PivOH
PivOH
PivOH
PivOH
PivOH
PivOH
PivOH
PivOH
PivOH
PivOH
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
Dioxane
EtOH
75
30
10
54
65
40
40
5
0
0
30
45
25
0
15
5
0
25
10
21
5
0
0
0
2
45
75
0
0
5
K
2
3
Cs
2
3
NaHCO
Na PO
PO
HPO
3
60
With the optimal conditions in hand, we next turned to
3
4
demonstrate the
generality of this iron-catalyzed
K
3
4
carbonylation (Scheme 1). Aryl iodides bearing electronically
deactivated, neutral, and activated moieties gave the
corresponding biaryl ketones in good to excellent yields with
65 high selectivities. The reaction conditions were compatible
with chloro, cyano, fluoro, trifluoro, and methoxy groups.
Iodotoluenes were productive coupling partners albeit 2-
methyl substitute had a mildly negative effect on reactivity
(3ga, 3ia-3ja). Interestingly, the transformation can move
Na
2
4
NaF
AcONa
DBU
Na
Na
Na
Na
Na
Na
2
2
2
2
2
2
CO
CO
CO
CO
CO
CO
3
3
3
3
3
3
Glycol
Toluene
DMSO
0
87
g
2
7
FeCl
2
PEG-400
g
2,
8
h
2
2
3
FeCl
Na
CO
PivOH
PEG-400
88
5
70
beyond simple aryl group and incorporate heteroaryl iodide
3ma). 1-Iodonaphthalene can also be utilized as a coupling
a
Reaction conditions (unless otherwise stated): 1a (0.25 mmol), 2a (0.375 mmol,
(
.
1
.5 equiv), FeCl
2
(10 mol%), base (0.5 mmol, 2 equiv), CsOH H
2
O (1.25 mmol, 5
partner, albeit with heating to 140 °C in the absence of PivOH,
to arrive at 3na in moderate isolated yield. Unfortunately, 4-
bromobenzotrifluoride was poorly reactive and gave the
75 desired product in only a 26% yield even at 140 °C (3fa).
Subsequently, a series of potassium aryltrifluoroborates
were explored (Scheme 2). They proved to efficiently couple
with typical aryl iodides under normal conditions. No
equiv), CHCl
3
(0.75 mmol, 3 equiv), additive (0.375 mmol, 1.5 equiv), solvent (2.0
o
mL), 120 C, and 24 h; Yields were determined by GC analysis using hexadecane
b
c
d
o
e
f
as internal standard. [Pd] (1 mol%). PivOH (1 equiv). 80 C. PPh
3
(2 mol%).
(99.99% based on trace metals,
(99.997% based on trace metals, Alfa Aesar), and
ultrapure NaI (99.999% based on trace metals, Acros).
g
h
PPh
3
(1 mol%). NaI (0.5 equiv). Ultrapure FeCl
CO
2
Alfa Aesar), ultrapure Na
2
3
2
| Journal Name, [year], [vol], 00–00
This journal is © The Royal Society of Chemistry [year]

Page 3 of 6
Green Chemistry
hindered potassium 2-methylphenyltrifluoroborate (2d) and
View Article Online
potassium 2-methoxyphenyltrifluoroborate (2e) provided the
DOI: 10.1039/C6GC02158A
desired biaryl ketones in 60% (3gd) and 77% (3ge) yields,
respectively. It is noteworthy that the particular reactive
hydroxyl group remained intact in the catalytic system (3gg).
Potassium naphthalene-2-trifluoroborate (2l) was found to be
a good coupling partner. Also potassium aryltrifluoroborates
bearing heterocyclic or acyclic amide moieties, even including
secodary amides underwent successful coupling with isolated
yields of 87%, 85%, 75%, 80%, and 75% (3gm-3gq).
2
2
3
3
4
4
0
5
0
5
0
5
Extension of this carbonylation process to arylboronic acids
has yielded promising results (Scheme 3). Interestingly, aryl
iodides having electron-withdrawing substituents (NO , CN, F, Cl,
2
and CF ), prone to Suzuki-Miyaura coupling to give biaryls,
3
underwent highly selective carbonylation coupling to provide the
desired products in satisfactory yields (5oa, 3ba, 3fa, 3ca, and
3
aa). In addition, the presence of a free acid did not compete with
the efficacy of the carbonylation event (5pa). The introduction of
a substituent in ortho-position of the aryl iodide had negligible
impact on the observed yields (3ia and 5qa). 1-Iodonaphthalene
and heteroaromatic aryl iodides could also be employed and gave
much higher yields than those of potassium aryltrifluoroborate
(3na 3ma, and 5sa). As shown in Scheme 4, a host of arylboronic
acids could be equally accommodated in good yields. The
electronic nature of the arylboronic acid had little impact on the
outcome of the present transformation. Arylboronic acid featuring
a free hydroxyl group was smoothly carbonylated (3gg). Also
naphthalene-2-boronic acid coupled well affording biarylketones
in 65% (5od) and 80% (3jl) yields. Furthermore, the method
could be extended to heterocyclic boronic acid (4e) when PivOH
Scheme
halides 1 with potassium aryl trifluoroborates 2a. Reation conditions (unless
otherwise noted): 1 (0.25 mmol), 2a (0.375 mmol), FeCl (0.025 mmol),
(0.75 mmol), NaI (0.125
1 Iron-catalyzed carbonylative Suzuki-Miyaura reaction of aryl
2
5
Na
2
CO
3
(0.5 mmol), CsOH·H
2
O (1.25 mmol), CHCl
3
o
a
o
mmol), PivOH (0.375 mmol), PEG-400 (2 mL), 120 C. No PivOH at 140 C.
b
c
KOAc (20 mol%) instead of PivOH. PivOH (0.5 equiv).
significant electronic effects were observed for meta- and
para-substituted potassium aryltrifluoroborates; the rates and
yields of reactions were comparable. Even the sterically
1
0
FeCl2 (10 mol%)
NaI (50 mol%)
O
I
(HO) B
2
R1
+
CHCl3
+
CsOH H2O (5 equiv)
Na2CO3 (2 equiv)
PivOH (1.5 equiv)
PEG-400 (2 mL)
R1
1
4a
5a
1
20 o
C
O
O
O
O
O2N
NC
HOOC
F3C
Me
5pa, 35 h, 75%a
3fa, 24 h, 77%
5
oa, 34 h, 87%
3ba, 24 h, 60%
O
O
O
O
F
Cl
3ga, 24 h, 90%
3ca, 27 h, 94%
3aa, 23 h, 82%
3ha, 24 h, 94%
O
O
OMe O
Me
O
Me
MeO
Me 3ka, 38 h, 87%
3la, 27 h, 84%
5qa, 35 h, 75%
3ia, 23 h, 90%
O
O
O
O
O
N
S
Ph
5ra, 28 h, 50%b
3ma, 45 h, 67%b
5sa, 27 h, 65%b
3na, 24 h, 82%
Scheme 3 Iron-catalyzed carbonylative Suzuki-Miyaura reaction of 4a with
0 various aryl iodides 1. Reation conditions (unless otherwise noted): 1 (0.25
5
Scheme
iodides 1 with various potassium aryl trifluoroborates 2. Reation conditions
unless otherwise noted): 1 (0.25 mmol), 2 (0.375 mmol), FeCl (0.025 mmol),
Na CO (0.5 mmol), CsOH·H O (1.25 mmol), CHCl (0.75 mmol), NaI (0.125
mmol), PivOH (0.375 mmol), PEG-400 (2 mL), 120
2
Iron-catalyzed carbonylative Suzuki-Miyaura reaction of aryl
mmol), 4a (0.375 mmol), FeCl
2 2 3 2
(0.025 mmol), Na CO (0.5 mmol), CsOH·H O
(1.25 mmol), CHCl (0.75 mmol), NaI (0.125 mmol), PivOH (0.375 mmol),
3
o
a
(
2
PEG-400 (2 mL), 120 C. No PivOH, Na
2
CO
3
(3equiv), and CsOH·H
2
O (6.0
b
1
5
2
3
2
3
equiv). PivOH (0.5 equiv).
o
C
.
55
This journal is © The Royal Society of Chemistry [year]
Journal Name, [year], [vol], 00–00 | 3

Green Chemistry
Page 4 of 6
View Article Online
DOI: 10.1039/C6GC02158A
Scheme 4 Iron-catalyzed carbonylative Suzuki-Miyaura coupling of aryl iodides 1
with various arylboronic acids 4. Reation conditions (unless otherwise noted): 1
(0.25 mmol), 4 (0.375 mmol), FeCl (0.025 mmol), Na CO (0.5 mmol), CsOH·H
(0.75 mmol), NaI (0.125 mmol), PivOH (0.375 mmol), PEG-
5
2
2
3
2
O
(
1.25 mmol), CHCl
3
o
a
4
00 (2 mL), 120 C. No PivOH and KOAc (20 mol%).
[
19]
was replaced by KOAc (20 mol%).
However, 2-
phenylethylboronic acid as an alkyl boronic acid was employed
to react with 1-chloro-4-iodobenzene (1a) under normal
conditions, leading to the desired alkyl aryl ketone in less than
1
0
4
0
Scheme
5
Proposed reaction mechanism for the iron-catalyzed
3
0% yield.
Particularly noteworthy was that the C-labeled version could
be prepared in a similar yield by simply exchanging chloroform
3
carbonylation utilizing CHCl as CO source.
13
1
3
1
5
for the commercially available C-labeled chloroform, utilizing
[19,25]
Based on these observations and previous studies
, the
the identical coupling conditions as in Scheme 3 (3la) [eqn (1)].
following mechanism can thus be proposed (Scheme 5).
Initially, CO is released from CHCl3 in the presence of
hydroxide base. Then, Fe (CO) L (A) is formed in situ from
FeCl2 with CO under normal conditions.
nucleophilic organoiron complex B
45
m
n x
[
19,26]
A highly
is generated through
[
19,27]
an addition reaction of A and arylboron with the assistance of
base and further undergoes intramolecular CO migratory
insertion to give organoiron complex C. Subsequently, C
50
Previous studies reported that the conversion of chloroform to
proceeds with S R1 type oxidative addition with aryl iodide
N
[
9-10]
[18-19]
CO can be realized by direct hydrolysis
situ generated intermediate dichlorocarbene in the presence of
strongly basic aqueous hydroxide solutions. To check the process 55 and the catalytically active A is regenerated in CO atmosphere.
or hydrolysis of in
to afford organoiron complex D.
Finally, reductive
[
8]
2
2
3
3
0
5
0
5
elimination of E provides the desired biarylketone product
of our case, an aryl iodide bearing alkene moiety (1o) was
In summary, we have documented an unprecedented iron-
catalyzed carbonylative Suzuki-Miyaura coupling utilizing
subjected to the normal conditions and didn’t undergo [2 + 1]-
[
22]
cycloaddition to afford the corresponding cyclopropane
[eqn
stoichiometric CHCl as the CO precursor to deliver a range
3
.
(2)]. Moreover, replacing the both chloroform and CsOH H O
of synthetically useful biaryl ketones in good to excellent
2
with 1 atm of CO resulted in 92% yield of 3aa [eqn (3)]. These 60 yields with high selectivities. This protocol employs readily
findings imply that intermediate dichlorocarbene can be ruled out
in the present reaction. In addition, a single-electron-acceptor
DDQ was added into the catalytic system and led to complete
suppression of the transformation [eqn (4)]. Furthermore, a
available and easy to handle catalysts and reagents and
1
3
exhibits a high degree of practicality. Importantly, the C-
labeled version could be realized simply by using the
1
3
commercially available C-labeled CHCl . The efficiency,
3
radical probe 1-(allyloxy)-2-iodobenzene (1o) was employed as 65 economy, and operational simplicity of this catalytic system
aryl iodide and gave a cyclization product, 3-methyl-2,3-
dihydrobenzofuran in 15% yield based on GC-MS analysis [eqn
linked with the substrate generality render this method
particularly attractive in organic synthesis. Further
mechanistic studies and the extension to other carbonylation
reactions are currently underway.
[
23]
(
2)]. And no any carbonylated product was observed [eqn (2)].
These results suggest that the present carbonylation process
[
24]
involves aryl radical intermediate.
70
4
| Journal Name, [year], [vol], 00–00
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X.X. Qi, L. B. Jiang, H. P. Li and X. -F. Wu, Chem. Eur.J., 2015,
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Notes and references
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) Z.
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10023 Nanjing (China). Fax: (+) 86-(0)25-8589-1455
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Electronic Supplementary Information (ESI) available. See
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This work was sponsored by the Natural Science Foundation of Jiangsu
Province (BK20161553), the Natural Science Foundation of China
21302099), the Natural Science Foundation of Jiangsu Provincial
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Journal Name, [year], [vol], 00–00 | 5

Green Chemistry
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DOI: 10.1039/C6GC02158A
Iron-Catalyzed Carbonylation of Aryl halides with Arylborons
Using Stoichiometric Chloroform as the Carbon Monoxide
Source
Hongyuan Zhao, Hongyan Du, Xiaorong Yuan, Tianjiao Wang and Wei Han*
–
Table of Contents Entry –
The highly effective iron-catalyzed carbonylative Suzuki-Miyaura coupling using
stoichiometric chloroform as the CO precursor has been developed.