Cobalt-Catalyzed Reductive Cross-Coupling Between Benzyl Chlorides and Aryl Halides

Article abstract of DOI:10.1002/adsc.201600378

A new protocol for the direct reductive cobalt-catalyzed arylation of benzyl chlorides has been developed in order to form functionalized diarylmethanes. A variety of reactive groups either on the aryl or the benzyl halide was employed. This represents the first cobalt-catalyzed reductive cross-coupling which does not require any ligand and pyridine. A reaction pathway is proposed involving a radical benzyl species. (Figure presented.).

Full text of DOI:10.1002/adsc.201600378

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DOI: 10.1002/adsc.201600378
Cobalt-Catalyzed Reductive Cross-Coupling Between Benzyl
Chlorides and Aryl Halides
Suman Pal,+a Sushobhan Chowdhury,+a Elodie Rozwadowski,a Audrey Auffrant,a,*
and Corinne Gosminia,*
a
LCM, CNRS, Ecole polytechnique, Universitꢀ Paris-Saclay, 91228 Palaiseau, France
Fax : (+33)-1-6933-4440; phone (+33)-1-6933-4400; e-mail: audrey.auffrant@polytechnique.edu or
corinne.gosmini@polytechnique.edu
+
These two authors contributed equally to this work.
Received: April 8, 2016; Revised: June 9, 2016; Published online: && &&, 0000
Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/adsc.201600378.
Abstract: A new protocol for the direct reductive
cobalt-catalyzed arylation of benzyl chlorides has
been developed in order to form functionalized di-
maceuticals.[5] This can, nevertheless, be conventional-
ly prepared by electrophilic aromatic substitution
(Friedel–Crafts benzylation),[6] but this method is
quite limited in terms of scope and the regioselectivity
may be difficult to control. Another possibility is a nu-
cleophilic aromatic substitution on a benzyl deriva-
tive[7] the efficiency of which can be altered by steric
ACHTUNGTRENNUNGarylmethanes. A variety of reactive groups either on
the aryl or the benzyl halide was employed. This
represents the first cobalt-catalyzed reductive cross-
coupling which does not require any ligand and pyr-
idine. A reaction pathway is proposed involving
a radical benzyl species.
À
hindrance. Aromatic C H activation offer another al-
ternative way to access diarylmethanes.[8] However,
the most employed strategy to prepare them remains
the transition metal-catalyzed coupling reaction em-
ploying either electrophilic benzyl derivatives[9] or
more rarely nucleophilic benzyl reagents[10] using Pd,
Ni, Cu, Fe, or Co as catalyst. Lately, benzyl alcohols
were also shown to be efficient as coupling partner in
palladium-catalyzed Suzuki–Miyaura coupling.[11] Ex-
Keywords: aryl halides; benzyl halides; cobalt;
cross-coupling; diarylmethanes
Transition metal-catalyzed cross-coupling reactions amples of direct electrophilic coupling to form diaryl-
between organometallic nucleophiles and organic methanes are rare: last year Weix et al. elegantly
electrophiles have become the dominant approach to demonstrated that benzyl mesylates reacted with aryl
[1]
À
form C C bonds during the last past decades. For halides in the presence of a nickel catalyst and
such transformations, palladium and nickel remain a cobalt phthalocyanine co-catalyst assisting the for-
the most employed metals both in academia and in- mation of the alkyl radical.[12] Following our first
dustry,[2] nevertheless high costs and scarcity or toxici- report of direct reductive couplings of aryl bromides
ty have motivated the search for alternatives. Then with alkyl halides,[13] using cobalt catalyst and manga-
copper, iron, and cobalt which are more economical nese conducted in DMF in the presence of pyridine,
and/or eco-compatible were found to be efficient for we were interested in developing milder reaction con-
a variety of coupling reactions.[3] A conceptually dif- ditions for benzyl-aryl couplings. Therefore, we report
ferent approach consists in the direct cross-coupling here a cobalt-catalyzed, easy synthesis of diarylme-
of two electrophiles, which presents the advantage to thanes by reductive cross-coupling of benzyl chlorides
avoid the handling and preparation of a stoichiometric and aryl halides tolerating various functional groups
and sensitive organometallic partner. Various combi- working at mild temperature, without ligand, with low
nations of aryl, alkenyl, acyl, allyl, or alkyl reagents equivalents of reductant, using acetonitrile as solvent,
were achieved with this methodology using Co, Pd, and no co-solvent.
Ni, or Fe as metal catalyst and Zn, Mn, or Mg as re-
In order to determine the optimal reaction condi-
ductant.[4] However, very few reports deal with the tions we focused on the reductive coupling of benzyl
preparation in such a way of the diarylmethane motif chloride and ethyl 4-bromobenzoate with the objec-
(vide infra), which is an important structure in phar- tive to replace toxic DMF and suppress pyridine as
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co-solvent. To reach this goal, as we thought that a ni- ature or 358C, both catalysts were more or less as
trogen-based ligand may help to stabilize the active productive (entries 9–12). Decreasing once more the
catalytic species in the absence of pyridine, we tested manganese loading to 2.2 equivalents (very close to
beside CoBr2 salt an unprecedented cobalt complex the mechanistic limit of 2.05 equivalents, see
featuring an easily synthesized tridentate N3 ligand Scheme 2) did not dramatically influence the outcome
(see the Supporting Information for its synthesis and of the reaction since the coupling product was formed
characterization). Our results are gathered in Table 1. in at least 70%. Interestingly with CoBr2 salt at room
The reactions were first conducted on a 1 mmol scale temperature 85% of product was observed. As these
of ethyl 4-bromobenzoate (ca. ~0.25 mmolmLÀ1) with reaction conditions are very simple, we decided to ex-
5% catalyst and 8 equivalents of manganese (en- plore the scope on this basis keeping in mind that
tries 1–8). Under these conditions higher tempera- both mild heating and use of [CoBr2L] may be at-
tures did not change much the yields but decreased tempted when those conditions are not satisfying.
the reaction time. In some cases, nevertheless, the
First, we studied the influence of a functional sub-
preformed complex [CoBr2L] gave higher yields than stituent on the aryl halide (Table 2). When the aryl
the cobalt salt (entries 1/2 and 5/6). Decreasing the
Table 2. Scope of aryl bromides.[a]
quantity of manganese to 4 equivalents gave at 358C
73 and 86% of the coupling product with CoBr2 and
the preformed complex, respectively. Reasoning that
the lower yield obtained with the cobalt salt may be
due to the purity of the commercial compound that
on a small scale can have a strong influence on the ef-
ficiency, we then operated with a more concentrated
reaction mixture (5 mmol of benzyl chloride in 4 mL
acetonitrile). Under these conditions at room temper-
Entry ArBr (FG) T [8C] GC yield [%]
at r.t./358C
Yield [%]
at r.t./358C
Table 1. Optimization study.[a]
1
2
3
(4-CN)
(2-CO2Et)
(3-CO2Et)
(2-CN)
r.t./35
r.t.
r.t.
70/78
80
72
62/71
74
65
4
r.t.
79
73
5
6
7
8
(4-CF3)
(2-CF3)
(3-CF3)
(4-COMe)
(2-COMe)
(4-SO2Me)
(4-NO2)
(4-Cl)
(2-Cl)
(3-Cl)
(4-F)
(2-F)
(3-F)
(H)
(4-Me)
2-naphthyl
(4-SMe)
(4-OMe)
(4-NMe2)
r.t.
r.t.
r.t./35
r.t.
r.t./35
r.t.
78
71
61/72
90
71
61
50/64
84
–/57
85
9
66/65
88
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Entry Co cat. (x%) Mn [y equiv.] T [8C] GC yield [%]
[b]
r.t.
–
–
1[b]
CoBr2 (5%)
[CoBr2L] (5%)
CoBr2 (5%)
[CoBr2L] (5%)
CoBr2 (5%)
[CoBr2L] (5%)
CoBr2 (5%)
[CoBr2L] (5%)
[CoBr2L] (5%)
CoBr2 (5%)
[CoBr2L] (5%)
CoBr2 (5%)
[CoBr2L] (5%)
CoBr2 (5%)
[CoBr2L] (2%)
CoBr2 (2%)
8
8
8
8
8
8
4
4
4
4
4
4
2.2
2.2
2.2
2.2
r.t.
r.t.
35
35
50
50
35
35
r.t.
r.t.
35
35
r.t.
r.t.
35
35
72
88
85
86
76
84
73
86
84
82
82
78
75
85[d]
78
70
r.t./35
r.t./35
r.t./35
r.t./35
r.t./35
r.t./35
35
65/74
66/72
72/75
60/57
58/56
68/71
70
58/69
58/67
65/–
54/–
52/–
65/–
2[b]
3[b]
4[b]
5[b]
6[b]
[c]
7[b]
–
–
[c]
8[b]
r.t.
72
9[c]
r.t./35
r.t./35
r.t./35
35
61/78
57/68
45/61
60
53/71
51/64
–/57
51
10[c]
11[c]
12[c]
13[c]
14[c]
15[c]
16[c]
[a]
All reactions were carried out on 5 mmol of ArBr,
7.5 mmol of C6H5CH2Cl, 11 mmol of Mn with 0.25 mmol
of CoBr2 in CH3CN (4 mL) with TFA (0.1 mL), GC
yields correspond to the heterocoupling fraction using
dodecane as internal standard, yields refer to the isolated
yields.
No reaction occurred.
The coupling product cannot be separated from the side
products.
[a]
Aryl bromide and benzyl chloride were used in a 1:1.5
ratio.
Using 1 mmol of aryl bromide in CH3CN (4 mL).
Using 5 mmol of aryl bromide in CH3CN (4 mL).
82% isolated yield.
[b]
[c]
[d]
[b]
[c]
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Table 3. Scope of benzyl chlorides.[a]
bromide is substituted by an electron-withdrawing
group (entries 1–11), the reaction worked quite well
at room temperature (see, for example, entries 2–6, 8)
except for the nitro derivative (entry 11) for which no
reaction occurred as often observed in these types of
cobalt-catalyzed reactions. Sometimes gentle heating
of the reaction mixture to 358C led to a slightly im-
proved yield (entries 1, 7).
This positive effect was not seen with the 2-COMe
(entry 9). For chloro-substituted aryl bromides (en-
tries 12–14), heating to 358C made the reaction quick-
er and more effective with isolated yields around
65%. For fluoro derivatives heating did not have this
positive effect, the coupling product was isolated in
52, 65, 54% from 2-, 3-, and 4-fluorophenyl bromides,
respectively. Reaction with non-activated aryl bro-
mides proceeded satisfactorily as well. Bromobenzene
reacted with benzyl chloride at 358C giving the cou-
pling product in 70% GC yield, unfortunately the
latter could not be chromatographically separated.
The reaction with p-bromotoluene is comparable
except that it worked at room temperature. To couple
2-bromonaphthalene heating was also necessary al-
lowing the coupling product to be isolated in 71%
yield. Reactions are more difficult for deactivated
aryl bromides (entries 21–23), for which isolated yield
vary between 50 and 65%.
The scope of benzyl chlorides was then investigated
(Table 3). Methyl-substituted benzyl chlorides cou-
pled efficiently at 358C (entries 1-3). These reaction
conditions were efficient with 3-methoxybenzyl chlo-
ride giving 64% of coupling product but were ineffi-
cient when this electron-donating substituent was in
position 2 or 4, since dimerization of benzyl chlorides
occurred predominantly. To avoid this side reaction
the benzyl chloride was added dropwise to the reac-
tion mixture, which allowed us to roughly double the
GC yield (entry 6) giving the coupling product in 58
and 54% starting from 4-methoxy- and 2-methoxy-
benzyl chloride, respectively. Another strategy could
be to increase the reactivity of the aryl halide using
the iodo derivative in place of the bromo, which may
avoid dropwise addition (entry 6). However in that
En-
try
(FG’)
FG
T [8C]
GC yield Yield [%]
at T8C
at T8C
1
2
3
4
5
6
7
8
9
10
11
12
13
14
(4-Me) 4-CO2Et
(3-Me) 4-CO2Et
(2-Me) 4-CO2Et
(3-OMe) 4-CO2Et
(4-OMe) 4-CO2Et
35
35
35
rt
r.t./35
80
84
73
76
74
65
68
64
32/28
63/38
60
–/–
58/–
54
(4-OMe) 4-CO2Et r.t.[b]/r.t.[c]
(2-OMe) 4-CO2Et
(4-F)
(3-F)
(4-Cl)
(3-Cl)
(3-CF3) 4-CO2Et
r.t.[b]
r.t./35
35
4-CO2Et
4-CO2Et
4-CO2Et
4-CO2Et
52/76
58
–/70
55
35/35[c]
35[c]
35[c]
35
20/72
73
66
68
68
63
(3-Me)
(4-F)
2-CN
4-CF3
84
62
76
-
[d]
35
[a]
GC yields correspond to the heterocoupling fraction
using dodecane as internal standard, yields refer to the
isolated yields.
[b]
[c]
[d]
Dropwise addition of benzyl chloride diluted in CH3CN
(2 mL) at 1.5 mLhÀ1.
Reaction with ethyl 4-iodobenzoate in place of ethyl 4-
bromobenzoate.
The coupling product cannot be separated from the side
products.
Scheme 1. Cross-coupling with a-substituted benzyl chloride.
case the slow addition was more efficient. Neverthe- obtain the cross-coupling product in good yield in
less, the use of ethyl iodobenzoate was an interesting a one-step procedure.
alternative for chloro- and trifluoromethyl-substituted
This reductive coupling was also attempted with
benzyl chlorides (see entries 10–12) whereas fluoro a heteroaryl ring either on the aryl or the alkyl part-
derivatives reacted satisfactorily at 358C under non- ner, the results are gathered in Table 4. Reactions
modified conditions (entries 8, 9). Couplings between with 2-Br-heteroaryl derivatives worked quite well
a functionalized aryl bromide and a substituted except in the case of 2-bromothiophene (entries 1, 3,
benzyl chloride were also conducted (entries 13, 14) 5). 3-Bromothiophene coupled satisfactorily only with
in decent yields
[CoBr2L] as precatalyst (entry 2) whereas for 3-bro-
This process was then investigated with a secondary mofuran, CoBr2 was sufficient (entry 6). When the
benzylic chloride (Scheme 1). As previously observed heterocycle was on the benzyl partner, reactions did
the a-substitution considerably increased the reactivi- not work under these simple conditions, indeed the
ty of the benzyl chloride towards cobalt.[9f] Thus, dimerization of the benzyl partner was generally the
dropwise addition of this compound allowed us to preferred pathway. This can be partially solved when
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Table 4. Coupling with heteroaromatic partners.[a]
Entry
ArX
ArCH2Cl
GC Yield [%]
1
2
3
4
5
6
7
8
2-Br-thiophene
3-Br-thiophene
2-Br-pyridine
3-Br-pyridine
2-Br-furan
3-Br-furan
4-CO2Et-C6H4-I 3-CH2Cl-thiophene
4-CO2Et-C6H4-I 2-CH2Cl-thiophene
BnCl
BnCl
BnCl
BnCl
BnCl
BnCl
13/4[b]
38/67[b,c]
99[d]
no reaction
70[c]/59[b]
55[c]/54[b]
–/60[e,f]
20[e]/36[g]
[a]
All reactions were carried out on 5 mmol of ArBr,
7.5 mmol of C6H5CH2Cl, 11 mmol of Mn with 0.25 mmol
of CoBr2 in CH3CN (4 mL) with TFA (0.1 mL), GC
yields correspond to the heterocoupling fraction using
dodecane as internal standard.
With [CoBr2L] in place of CoBr2 as precatalyst.
The coupling product cannot be separated from the side
products.
Scheme 2. Postulated catalytic cycle.
[b]
[c]
[d]
[e]
Isolated yield: 86%.
Reaction with ethyl 4-iodobenzoate in place of ethyl 4-
bromobenzoate.
[f]
Isolated yield: 57%.
[g]
Dropwise addition of benzyl chloride diluted in CH3CN
(2 mL) at 1.5 mLhÀ1 to ethyl 4-iodobenzoate solution.
Scheme 3. Reaction with TEMPO.
ligand and pyridine as co-solvent, and proceeds
using the corresponding aryl iodide (entry 7) together smoothly at room temperature or 358C. Noteworthy
with the slow addition of the alkyl partner in the case when the catalyst loading was reduced to 2 mol% the
of 3-benzylthiophene (entry 8).
preformed catalyst [CoBr2L] gave a better yield than
Our postulated mechanism (Scheme 2) is similar to CoBr2. The low price of the catalyst used and the
the one we proposed for the aryl-alkyl,[13] aryl-aryl,[14] mild and bench-friendly conditions make this reaction
and aryl-vinyl[15] couplings. To enter the catalytic an alternative to more classical methodologies involv-
cycle, the catalyst has to be reduced to CoI, then oxi- ing stoichiometric organometallic species. This new
dative addition of aryl halide gives a CoIII intermedi- cobalt-catalyzed methodology allows easy access to
ate. The latter can be reduced by manganese to a CoII functionalized diarylmethanes. The proposed mecha-
derivative, which is then able to react with the benzyl nism suggests an intermediate radical benzylic species
reagent yielding another CoIII species, from which the as already reported with alkyl compounds in the pres-
coupling product is released by reductive elimination, ence of cobalt catalyst.
regenerating the active catalyst. To prove the involve-
ment of a benzyl radical, a control experiment was
conducted in the presence of TEMPO (2,2,6,6-tetra-
methylpiperidin-1-yl oxyl). In that case the efficiency
Experimental Section
of the reaction was highly altered (Scheme 3).
General Procedure
In summary, we have reported a new practical Co-
catalyzed cross-coupling of various functionalized
benzyl chlorides and aryl halides allowing the synthe-
sis of various diarylmethanes. This protocol tolerates
a large number of functional groups and yields range
from modest to excellent. Remarkably, this procedure
To a solution of aryl bromide (5.0 mmol) and benzyl chlo-
ride (7.5 mmol) in CH3CN (4.0 mL), manganese powder
(2.2 equiv., 11.0 mmol, 605 mg) was added. Trifluoroacetic
acid (0.1 mL) was added to it in order to activate manganese
followed by the addition of dodecane (0.1 mL) as internal
standard. The reaction mixture was stirred for approximate-
is the first reductive cross-coupling reaction without ly 10 min. Then, CoBr2 (5 mol%, 0.25 mmol, 55 mg) was
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added and the resulting reaction mixture was stirred at the
indicated temperature until the disappearance of either of
the starting materials. Upon completion, the mixture was
then quenched with a solution of 2M HCl (25 mL) or with
saturated NH4Cl solution (in case of amino compounds) and
was stirred vigorously until layers turned clear. The solution
was then extracted with CH2Cl2 or EtOAc (3ꢂ25 mL), dried
over MgSO4, filtered and concentrated under vacuum. Pu-
rification of the resulting oil or solid by flash chromatogra-
phy over silica with pentane, petroleum ether/diethyl ether
(or ethyl acetate) mixtures afforded the pure compounds.
[6] a) K. Mertins, I. Lovel, J. Kischel, A. Zapf, M. Beller,
Adv. Synth. Catal. 2006, 348, 691–695; b) M. Rueping,
B. J. Nachtsheim, Beilstein J. Org. Chem. 2010, 6, No. 6.
[7] H. Duan, L. K. Meng, D. H. Bao, H. Zhang, Y. Li,
A. W. Lei, Angew. Chem. 2010, 122, 6531–6534; Angew.
Chem. Int. Ed. 2010, 49, 6387–6390.
[8] a) L. Ackermann, P. Novak, Org. Lett. 2009, 11, 4966–
4969; b) Y. Aihara, M. Tobisu, Y. Fukumoto, N. Chata-
ni, J. Am. Chem. Soc. 2014, 136, 15509–15512; c) W. G.
Xu, R. Paira, N. Yoshikai, Org. Lett. 2015, 17, 4192–
4195.
[9] a) R. Kuwano, M. Yokogi, Org. Lett. 2005, 7, 945–947;
b) M. McLaughlin, Org. Lett. 2005, 7, 4875–4878; c) R.
Singh, M. S. Viciu, N. Kramareva, O. Navarro, S. P.
Nolan, Org. Lett. 2005, 7, 1829–1832; d) C. C. Kofink,
P. Knochel, Org. Lett. 2006, 8, 4121–4124; e) G. A. Mo-
lander, M. D. Elia, J. Org. Chem. 2006, 71, 9198–9202;
f) M. Amatore, C. Gosmini, Chem. Commun. 2008,
5019–5021; g) B. Liegault, J. L. Renaud, C. Bruneau,
Chem. Soc. Rev. 2008, 37, 290–299; h) A. Lopez-Perez,
J. Adrio, J. C. Carretero, Org. Lett. 2009, 11, 5514–5517;
i) R. B. Bedford, M. Huwe, M. C. Wilkinson, Chem.
Commun. 2009, 600–602; j) P. Maity, D. M. Shacklady-
McAtee, G. P. A. Yap, E. R. Sirianni, M. P. Watson, J.
Am. Chem. Soc. 2013, 135, 280–285; k) M. L. N. Rao,
R. J. Dhanorkar, RSC Adv. 2013, 3, 6794–6798; l) F.
Zhao, Q. Tan, F. H. Xiao, S. F. Zhang, G. J. Deng, Org.
Lett. 2013, 15, 1520–1523; m) Q. Zhou, H. D. Srinivas,
S. Dasgupta, M. P. Watson, J. Am. Chem. Soc. 2013,
135, 3307–3310.
[10] a) K. Itami, M. Mineno, T. Kamei, J. Yoshida, Org.
Lett. 2002, 4, 3635–3638; b) A. Flaherty, A. Trunkfield,
W. Barton, Org. Lett. 2005, 7, 4975–4978; c) M. A.
Schade, A. Metzger, S. Hug, P. Knochel, Chem.
Commun. 2008, 3046–3048; d) C. Duplais, A. Krasov-
skiy, A. Wattenberg, B. H. Lipshutz, Chem. Commun.
2010, 46, 562–564; e) V. Krasovskaya, A. Krasovskiy,
A. Bhattacharjya, B. H. Lipshutz, Chem. Commun.
2011, 47, 5717–5719; f) J. C. Tellis, D. N. Primer, G. A.
Molander, Science 2014, 345, 433–436; g) A. D. Be-
nischke, I. Knoll, A. Rerat, C. Gosmini, P. Knochel,
Chem. Commun. 2016, 52, 3171–3174.
Acknowledgements
We thank Ecole polytechnique for postdoctoral fellowships to
S.P. and S.C. and CNRS for financial support. We are grate-
ful to Dr. Sophie Bourcier for HR-MS measurements.
References
[1] a) Metal-catalyzed cross-coupling reactions, 2nd edn.,
(Eds.: A. de Meijere, F. Diederich), Wiley-VCH, Wein-
heim, 2004; b) Transition Metals for Organic Synthesis:
Building Blocks and Fine Chemicals, 2nd edn., (Eds.: M.
Beller, C. Bolm), Wiley-VCH, Weinheim, 2008; c) New
trends in cross-coupling: theory and application, (Ed.:
T. J. Colacot), RSC Publishing, Cambridge, 2015.
[2] C. C. C. Johansson Seechurn, M. O. Kitching, T. J. Cola-
cot, V. Snieckus, Angew. Chem. 2012, 124, 5150–5174;
Angew. Chem. Int. Ed. 2012, 51, 5062–5085.
[3] a) S. Messaoudi, J. D. Brion, M. Alami, Eur. J. Org.
Chem. 2010, 6495–6516; b) G. Cahiez, A. Moyeux,
Chem. Rev. 2010, 110, 1435–1462; c) G. Evano, C. The-
unissen, A. Pradal, Nat. Prod. Rep. 2013, 30, 1467–
1489; d) I. Bauer, H. J. Knolker, Chem. Rev. 2015, 115,
3170–3387.
[4] a) D. A. Everson, D. J. Weix, J. Org. Chem. 2014, 79,
4793–4798; b) C. E. I. Knappke, S. Grupe, D. Gartner,
M. Corpet, C. Gosmini, A. Jacobi von Wangelin, Chem.
Eur. J. 2014, 20, 6828–6842; c) D. J. Weix, Acc. Chem.
Res. 2015, 48, 1767–1775.
[11] Z. C. Cao, D. G. Yu, R. Y. Zhu, J. B. Wei, Z. J. Shi,
Chem. Commun. 2015, 51, 2683–2686.
[5] a) L. W. Hsin, C. M. Dersch, M. H. Baumann, D. Staf-
ford, J. R. Glowa, R. B. Rothman, A. E. Jacobson,
K. C. Rice, J. Med. Chem. 2002, 45, 1321–1329; b) A.
Kleemann, J. Engel, B. Kutscher, D. Reichert, Pharma-
ceutical Substances, Thieme, Stuttgart, 2008; c) Y. Q.
Long, X. H. Jiang, R. Dayam, T. Sanchez, R. Shoemak-
er, S. Sei, N. Neamati, J. Med. Chem. 2004, 47, 2561–
2573.
[12] L. K. G. Ackerman, L. L. Anka-Lufford, M. Naodovic,
D. J. Weix, Chem. Sci. 2015, 6, 1115–1119.
[13] M. Amatore, C. Gosmini, Chem. Eur. J. 2010, 16, 5848–
5852.
[14] A. Moncomble, P. Le Floch, C. Gosmini, Chem. Eur. J.
2009, 15, 4770–4774.
[15] A. Moncomble, P. Le Floch, A. Lledos, C. Gosmini, J.
Org. Chem. 2012, 77, 5056–5062.
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COMMUNICATIONS
6 Cobalt-Catalyzed Reductive Cross-Coupling Between
Benzyl Chlorides and Aryl Halides
Adv. Synth. Catal. 2016, 358, 1 – 6
Suman Pal, Sushobhan Chowdhury, Elodie Rozwadowski,
Audrey Auffrant,* Corinne Gosmini*
Adv. Synth. Catal. 0000, 000, 0 – 0
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ꢁ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÞÞ
These are not the final page numbers!