Olefin-assisted iron-catalyzed alkylation of aryl chlorides

Article abstract of DOI:10.1002/adsc.201300095

A selective and operationally simple ironcatalyzed cross-coupling of aryl chlorides with alkylmagnesium halides has been developed. The reaction tolerates various functional groups and exhibits high chemoselectivity even in the presence of aryl bromides. Mechanistic studies indicate the essential role of the olefin substituent for substrate activation. Competing polymerization and reduction are effectively suppressed.

Full text of DOI:10.1002/adsc.201300095

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DOI: 10.1002/adsc.201300095
Olefin-Assisted Iron-Catalyzed Alkylation of Aryl Chlorides
Samet Gꢀlak,a Tim N. Gieshoff,a and Axel Jacobi von Wangelina,*
a
Institute of Organic Chemistry, University of Regensburg, Universitaetsstr. 31, 93053 Regensburg, Germany
Fax : (+49)-(0)941-943-4617, phone: (+49)-(0)941-943-4802; e-mail: axel.jacobi@ur.de
Received: January 31, 2013; Revised: June 21, 2013; Published online: August 9, 2013
Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/adsc.201300095.
Abstract: A selective and operationally simple iron-
catalyzed cross-coupling of aryl chlorides with al-
kylmagnesium halides has been developed. The re-
action tolerates various functional groups and ex-
hibits high chemoselectivity even in the presence of
aryl bromides. Mechanistic studies indicate the es-
sential role of the olefin substituent for substrate
activation. Competing polymerization and reduc-
tion are effectively suppressed.
on biaryl couplings,[7] we have developed practical
iron-catalyzed alkylations of aryl chlorides which ex-
ploit an olefin-assisted activation of strong C Cl
bonds. This mode of activation is complementary to
that induced by electron-deficient substituents
(Scheme 1)
Earlier work in our group revolved around biaryl-
coupling reactions that utilized the coordinating abili-
ty of olefin-substituted aryl chlorides to iron and
cobalt catalysts.[7] We were delighted to find that the
paradigm of olefin-assisted aryl chloride activation
also facilitates alkylative couplings. The influence of
various substituents on the reactivity of chloroarenes
is shown in Table 1. Iron-catalyzed alkylations of
highly activated chloroarenes were already reported
to proceed at room temperature, but low conversions
À
Keywords: cross-coupling; Grignard reactions; iron;
olefin complexes; styrenes
Transition metal-catalyzed cross-coupling reactions were observed in the absence of electronegative sub-
are central to the synthesis of aromatic fine chemicals, stituents.[5] Isolated examples of alkylative coupling at
natural products, pharmaceuticals, and materials.[1] high temperatures with excess amounts of Grignard
Over the past decade, a major research effort has reagents were reported.[5f]
been devoted to Pd and Ni catalysts and the utiliza-
Initial experiments on optimization and scope
tion of activated electrophiles (mostly aryl bromides showed that iron-catalyzed alkylations of chlorostyr-
and iodides), for which numerous protocols were re- enes are feasible when the vinyl substituents (i) can
ported in the literature.[2] Only recently, iron-cata- adopt a co-planar orientation to the arene and (ii) ex-
lyzed cross-coupling – which can be performed under hibit low steric hindrance (Table 1). para- and meta-
practical conditions with cheap and ligand-free iron chlorostyrenes containing monosubstituted olefins en-
catalysts – was rediscovered as an attractive alterna- gaged in polymerization.[8] The proximal chloro sub-
tive to noble or toxic metal catalysis.[3] Easy accessi-
bility, low price, and low molecular weight make aryl
chlorides especially attractive starting materials. How-
ever, their employment in cross-coupling reactions re-
À
mains a great challenge due to the strong C Cl bond.
Many protocols capitalize on electronegative hetero-
ACHTUNGTRENNUNGatom-based substituents (e.g., CO2R, CN, pyridyl, F)
À
to facilitate reductive C Cl bond cleavage at low
valent catalysts.[4] Consistently, iron-catalyzed alkyla-
tions were only reported for electron-poor aryl chlor-
ides.[5] Surprisingly, hydrocarbon substituents have re-
ceived very little attention as activating groups in the
context of cross-coupling.[6] A conclusive example is
the facilitation of reductive elimination by p-accept-
ing olefins in nickel-catalyzed cross-coupling reactions
by Knochel et al.[6f,h] As an extension of recent work Scheme 1. Modes of chloroarene activation.
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Table 1. Substituent effects.
Table 2. Selected optimization experiments.
Aryl Chloride
Yield [%][a]
81[b]
Entry
Change from standard conditions
2/3 [%][a]
1
2
3
4
5
6
7
8
9
10
– (~0.2M in 1)
97/1
59/17
73/10
32/14 (56)
86/9
addition of RMgBr over 2 sec
addition of RMgBr over 40 min
2M in 1
R=4-CO2Me
R=2-Me
R=H
91[c]
1 (4)
6 (9)
8 (9)
FeCl3 (98%)
FeCl3 (99.99%)
no NMP
Et2O instead of THF
addition of 20 mol% TMEDA
R=2-F
88/5
2/10 (28)
25/29 (75)
56/18
R=H
R=Me
52 (100)
9 (15)
CoCl2 instead of Fe
N
9/87
d
6 (32)
[a]
GC yields; conversion of 1 in parentheses if not >95%.
R1 =R2 =R3 =H
9 (48)[d]
67 (73)
66 (70)
21 (25)
15 (18)
7 (12)
R1 =Me, R2 =R3 =H
R1 =R3 =H, R2 =Me
R1 =R2 =Me, R3 =H
R1 =H, R2 =R3 =Me
R1 =R2 =R3 =Me
trations (<0.2M of 1) in THF/NMP (10:1 v/v) result-
ed in high cross-coupling selectivity (entries 1 and
4).[13] Significant polymerization was observed in the
absence of catalyst (GPC-MS).[8] Comparable yields
and selectivities were obtained with 98% pure
R1 =R3 =H, R2 =Ph
59 (62)
Fe
catalyst precursors.[14] Catalytic NiCl2 (<7%) and
Pd(acac)2 (no conversion) showed very low activity,
ACHTUNGTRNE(NUNG acac)3, 98% FeCl3, and 99.9% FeCl3 as commercial
49 (51)
AHCTUNGTRENNUNG
whereas CoCl2 led to selective dehalogenation
(entry 10).
The strongly activating effect of an olefin substitu-
ent in the cross-coupling of electron-rich aryl chlor-
ides became apparent: 2-Chloro-1-methoxy-3-vinyl-
benzene exhibited far superior reactivity than 2-
[a]
[b]
[c]
[d]
GC yields; conversion in parentheses.
With n-C14H29MgBr, ref.[5d]
With n-C6H13MgBr, ref.[5d]
Polymer formation detected by GPC-MS.
stituent in 2-chlorostyrene (1) sufficiently prevents chloroACTHNUTRGNEaNUG nisole, despite the increased steric hindrance
polymerization and allows selective alkylation. In a- of the former (Scheme 2). We then subjected a series
methyl-2-chlorostyrene, the olefin and arene planes of other ortho-chlorostyrenes to the optimized reac-
À
are twisted, so that C Cl activation is largely inhibit- tion conditions (Table 3). Gratifyingly, the protocol
ed. Disubstituted olefins in para-position effect clean proved rather general displaying good tolerance of
cross-coupling, while increased steric bulk shuts down (silyl)ethers, amines, acetals, methylthio, chloro, and
this pathway. It is important to note that similar con- fluoro substituents. While primary and secondary al-
ditions in the presence of strong bases, nucleophiles, kylmagnesium halides could be reacted, tert-butyl-
and reductants (i.e., RMgX) were used in polymeri- magnesium chloride afforded polymers.
zation,[8]
hydrodehalogenation,[9]
hydro-
Alkylative coupling was also observed with m- and
ACHTUNGTRENNUNG
(carbo)metalation,[10] and Heck reactions,[11] all of p-chlorostyrenes, benzannelated aryl chlorides and
which are effectively suppressed (Scheme 1).
with trisubstituted olefin substituents (Table 4). 1-
Further optimization was performed with 2-chloro- Chloronaphthalene and 9-chloroanthracene allowed
ACHTUNGTRENNUNG
addition of another 2 mol% FeACTHNUTRGENUG(N acac)3. Dilute concen- Scheme 2. Olefin-assisted alkylation.
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Olefin-Assisted Iron-Catalyzed Alkylation of Aryl Chlorides
Table 3. Alkylations of ortho-chlorostyrenes.
Table 4. Alkylations of other aryl chlorides.[a]
Cross-Coupling Products
Yield [%]
Product
Yield [%]
R=H, n=9
R=H, n=11
R=NMe2, n=9
95
90
73
n=9
=11
71 (90)[b,c]
73 (90)[b,c]
R=H
R=OMe
71
72[a]
R=Me
R=Ph
63 (80)[b,c]
60 (80)[c,d]
R’’=OTBDMS
R’’=H
70
74[b]
R=H
R=C2H3
75 (80)
75 (85)[c]
–
96
81
84
72
78
73
R1 =CF3
R2 =F
R2 =Cl
R3 =OMe
R2 =R3 =OMe
n=1
n=4
52[a,c]
80
[a]
Conversion in parentheses if <95%.
Competing deprotonation at allylic position by rapid
[b]
Grignard addition (<20 min).
10–15% dehalogenation.
188C.
Mixture of 1- and 2-chloronaphthalene (85/15) as starting
material.
[c]
[d]
[e]
Scheme 3. Synthesis of 2-alkyl-1,3-butadienes.
The crucial role of olefin substituents in the activa-
À
tion of aromatic C Cl linkages was also illustrated by
the employment of chlorostyrene dimers.[16] Both
meta- and para-substituted 1,3-bis(chlorophenyl)pro-
pene derivatives underwent chemoselective coupling
at the chlorostyryl termini, respectively (Scheme 4).
The non-conjugated chlorophenyl moieties did not
engage in cross-coupling. Even more compelling is
the highly chemoselective cross-coupling of 1-bromo-
2-((3-chloro-4-vinylphenoxy)methyl)benzene
[a]
5 mol% FeACHTUNGTRENNUNG(acac)3, 1.5 equiv. R’MgBr.
[b]
Addition of 1 equiv. MeMgBr (THF, 188C) to 12-bromo-
dodecan-1-ol prior to Grignard formation.
~15% dehalogenation.
[c]
clean alkylations even in the absence of vinyl groups. (Scheme 5). Alkylative substitution occurred exclu-
We have expanded the scope of this protocol to also sively at the aromatic chloride moiety (Cl vs. Br
include 2-chloroprene, which can be viewed as a trun- >15:1).[17]
cated derivative of chlorostyrenes. Cross-coupling
As far as the mechanism is concerned, iron-olefin
methods have largely neglected this bulk monomer complexes in lower oxidation states were already
for chloroprene rubber (Neopren, Baypren).[15] In the shown to be highly active pre-catalysts for cross-cou-
presence of an iron catalyst, rapid alkylation with al- pling reactions.[18] The intermediacy of olefin com-
kylmagnesium halides was observed under standard plexes is also plausible when invoking rapid b-hydride
conditions (Scheme 3).
eliminations of alkyl-iron species, which are operative
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Scheme 4. Intramolecular chemoselective alkylation.
Scheme 6. Secondary kinetic isotope effects.
Scheme 5. Intramolecular chemoselective alkylation.
in the reduction of iron salts,[13,19] hydrodehalogena-
tion,[9] and olefin isomerization.[20] When non-volatile
and sterically unhindered olefins are formed, b-hy-
dride eliminations are reversible (hydrometalation),
so that FeACHTUNGTRENNUNG(olefin) complexes can be viewed as off-
cycle intermediates of cross-coupling reactions.[13,18b,20b]
Based on earlier studies with chlorostyrenes,[7] we
postulate initial olefin coordination to the catalyst
Scheme 7. Radical probe experiments.
species followed by haptotropic[21] migration along the tivities (Scheme 7). Performing both reactions in
conjugated p-system.[12] We prepared deuterium-la- THF-d8 (10% NMP) showed also no formation of d-
beled 2-chlorostyrene (1) and 1-chloro-4-(prop-1- styrenes. It should also be noted, that in all reactions
enyl)benzene (4) by ketone reduction with LiAlD4.[22] divinylbiaryls were formed in less than 5% yield via
Competition experiments with equimolar mixtures of formal reductive dehalogenative dimerization of the
d1-1 and 1 (50% overall deuterium content) displayed chlorostyrene starting materials. The participation of
a secondary kinetic isotope effect (28 KIE, kH/kD = olefin-coordinated iron complexes, rather than free
1.5). This clearly indicates that olefin coordination to radical intermediates, is also illustrated from the sub-
the catalyst is rate-determining for substrate conver- strate scope in Table 1 (bottom). With higher substitu-
sion (Scheme 6). However, a negligible 28 KIE (~1.0) tion of the double bond, less activation was observed.
was observed for p-chlorostyrene derivative 4. The An inhibitory effect of tri- and tetrasubstituted vinyl
proximal substituents in ortho-chlorostyrenes appear groups was observed in reactions of 4-chlorostyrene
to trigger a different mechanism than their counter- derivatives. The good reactivity of the cyclopentenyl
parts with distal olefin and chloro groups, as olefin co- derivative is due to ring strain and the resulting stron-
ordination is not rate-determining for the latter. Gen- ger metal-olefin coordination.[24]
À
erally, cleavage of the C Cl linkage can follow an
In summary, we have demonstrated that rapid iron-
iron-centered formal oxidative addition pathway or catalyzed alkylation can be effected with electron-rich
single electron transfer (SET) mechanism and result aryl chlorides that bear a vinyl substituent. The signif-
in the generation of aryl-iron or aryl radical species, icance of this work lies in the conversion of electron-
respectively.[23] The addition of radical scavengers to rich aryl chlorides (Scheme 2).
the cross-coupling reactions provided good indications
Alkylation of o-chlorostyrenes proceeds via rate-
that free radical intermediates can be excluded. The determining olefin coordination possibly followed by
À
presence of 1,1-diphenylethylene and stilbene, respec- formal oxidative addition of the C Cl linkage to a re-
tively, did not significantly affect cross-coupling selec- duced iron catalyst which is generated by reduction of
2200
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Olefin-Assisted Iron-Catalyzed Alkylation of Aryl Chlorides
FeACHTUNGTRENNUNG
(acac)3 with alkylmagnesium halides.[13,19] The pro-
[6] a) Review: J. B. Johnson, T. Rovis, Angew. Chem. 2008,
120, 852–884; Angew. Chem. Int. Ed. 2008, 47, 840–871;
b) J. B. Johnson, E. A. Bercot, J. M. Rowley, G. W.
Coates, T. Rovis, J. Am. Chem. Soc. 2007, 129, 2718–
2725; c) G. Chen, J. Gui, L. Li, J. Liao, Angew. Chem.
2011, 123, 7823–7827; Angew. Chem. Int. Ed. 2011, 50,
7681–7685; d) E. A. Bercot, T. Rovis, J. Am. Chem.
Soc. 2005, 127, 247–254; e) J. Terao, H. Watanabe, A.
Ikumi, H. Kuniyasu, N. Kambe, J. Am. Chem. Soc.
2002, 124, 4222–4223; f) A. E. Jensen, P. Knochel, J.
Org. Chem. 2002, 67, 79–85; g) T. Yamamoto, M. Abla,
J. Organomet. Chem. 1997, 535, 209–211; h) A. Devasa-
gayaraj, T. Stꢀdemann, P. Knochel, Angew. Chem.
1995, 107, 2952–2954; Angew. Chem. Int. Ed. Engl.
1995, 34, 2723–2725; i) K. Tatsumi, A. Nakamura, S.
Komiya, A. Yamamoto, T. Yamamoto, J. Am. Chem.
Soc. 1984, 106, 8181–8188; j) M. Tobisu, I. Hyodo, M.
Onoe, N. Chatani, Chem. Commun. 2008, 6013–6015.
[7] a) S. Gꢀlak, O. Stepanek, J. Malberg, B. Rezaei Rad,
M. Kotora, R. Wolf, A. Jacobi von Wangelin, Chem.
Sci. 2013, 4, 776–784; b) S. Gꢀlak, A. Jacobi von Wan-
gelin, Angew. Chem. 2012, 124, 1386–1390; Angew.
Chem. Int. Ed. 2012, 51, 1357–1361.
[8] a) GPC-MS analyses at the Institute of Physical
Chemistry, University of Cologne, Prof. B. Tieke;
b) anionic polymerizations: A. Hirao, S. Loykulnant, T.
Ishizone, Prog. Polym. Sci. 2002, 27, 1399–1471; c) poly-
merizations initiated by Grignard reagents: A. Soum,
M. Fontanille, P. Sigwalt, J. Polymer Sci. 1977, 15, 659–
673; d) P. E. M. Allen, A. G. Moody, Macromol. Chem.
Phys. 1965, 83, 220–225; e) P. E. M. Allen, J. F. Harrod,
Macromol. Chem. Phys. 1959, 32, 153–169; f) P. E. M.
Allen, J. F. Harrod, Macromol. Chem. Phys. 1953, 32,
153–169.
tocol is chemoselective and allows reactions in the
presence of various functional groups including vari-
ous aryl bromide or chloride moieties. The vinyl sub-
stituents themselves constitute versatile functional
groups. Unlike many conventional auxiliaries and di-
recting groups, alkenyl substituents permit various op-
portunities for further functionalization.
Experimental Section
General Procedure
FeACHTUNGTRENNUNG(acac)3 (7 mg, 0.02 mmol, 2 mol%) was loaded into a reac-
tion vial (25 mL) under an atmosphere of argon. The vial
was sealed with a rubber septum and the solvent mixture
THF/NMP (freshly dried and distilled, 4.4 mL, 10/1, v/v)
added with a syringe. The red solution was placed in a water
bath (308C) and treated with the chlorostyrene (1 mmol)
followed by the freshly prepared alkylmagnesium bromide
(0.25 mmol, 0.5M in THF). The remaining 0.95 mmol of
Grignard reagent were slowly added with a syringe pump
over a period 80 min (or 40 min for a- or b-substituted
chlorostyrenes). The mixture was then stirred at 308C for
another 40 (or 80) min. Then, saturated aqueous NaHCO3
was added and the mixture extracted with ethyl acetate (3ꢂ
5 mL). The combined organic phases were dried (Na2SO4)
and concentrated under vacuum. SiO2 flash column chroma-
tography (n-pentane/ethyl acetate) afforded the alkylstyr-
enes.
References
[9] a) W. M. Czaplik, S. Grupe, M. Mayer, A. Jacobi von
Wangelin, Chem. Commun. 2010, 46, 6350–6352; b) H.
Guo, K. Kanno, T. Takahashi, Chem. Lett. 2004, 33,
1356.
[1] a) Metal-Catalyzed Cross-Coupling Reactions, (Eds.: A.
de Meijere, F. Diederich), Wiley-VCH, Weinheim,
2004.
[10] Hydrometalations: a) M. D. Greenhalgh, S. P. Thomas,
Synlett 2013, 24, 531–534; b) E. Shirakawa, D. Ikeda, S.
Masui, M. Yoshida, T. Hayashi, J. Am. Chem. Soc.
2012, 134, 272–279; c) E. Nakamura, N. Yoshikai, J.
Org. Chem. 2010, 75, 6061–6067; d) B. D. Sherry, A.
Fꢀrstner, Chem. Commun. 2009, 7116–7118; e) M. Na-
kamura, A. Hirai, E. Nakamura, J. Am. Chem. Soc.
2000, 122, 978–979. Carbometalations: f) T. Hata, S.
Sujaku, N. Hirone, K. Nakano, J. Imoto, H. Imade, H.
Urabe, Chem. Eur. J. 2011, 17, 14593–14602; g) Y.
Wang, E. A. F. Fordyce, F. Y. Chen, H. W. Lam, Angew.
Chem. 2008, 120, 7460–7463; Angew. Chem. Int. Ed.
2008, 47, 7350–7353; h) I. Marek, N. Chinkov, D.
Banon-Tenne, in: Metal-Catalyzed Cross-Coupling Re-
actions, (Eds.: A. de Meijere, F. Diederich), Wiley-
VCH, Weinheim, 2004, pp 395–478; i) I. Marek, J.
Chem. Soc. Perkin Trans. 1 1999, 535–544; j) S. Nii, J.
Terao, N. Kambe, J. Org. Chem. 2004, 69, 573–576.
[2] a) I. P. Beletskaya, V. P. Ananikov, Chem. Rev. 2011,
111, 1596–1636; b) C. E. I. Knappke A. Jacobi von
Wangelin, Chem. Soc. Rev. 2011, 40, 4948–4962; c) E.-i.
Negishi, Angew. Chem. 2011, 123, 6870–6897; Angew.
Chem. Int. Ed. 2011, 50, 6738–6764; d) A. Suzuki,
Angew. Chem. Int. Ed. 2011, 50, 6723–6737.
ˇ
[3] a) W. M. Czaplik, M. Mayer, J. Cvengros, A. Jacobi von
Wangelin, ChemSusChem 2009, 2, 396–417; b) B. D.
Sherry, A. Fꢀrstner, Acc. Chem. Res. 2008, 41, 1500–
1511; c) C. Bolm, J. Legros, J. Le Paih, L. Zani, Chem.
Rev. 2004, 104, 6217–6254.
[4] A. F. Littke, G. C. Fu, Angew. Chem. 2002, 114, 4350–
4386; Angew. Chem. Int. Ed. 2002, 41, 4176–4211.
[5] a) B. Scheiper, M. Bonnekessel, H. Krause, A. Fꢀrst-
ner, J. Org. Chem. 2004, 69, 3943–3949; b) A. Fꢀrstner,
A. Leitner, Angew. Chem. 2003, 115, 320–323; Angew.
Chem. Int. Ed. 2003, 42, 308–311; c) M. Hocek, H.
ˇ
Dvorꢃkovꢃ, J. Org. Chem. 2003, 68, 5773–5776; d) A.
ˇ
[11] a) D. Necas, P. Drabina, M. Sedlak, M. Kotora, Tetrahe-
Fꢀrstner, A. Leitner, M. Mꢄndez, H. Krause, J. Am.
Chem. Soc. 2002, 124, 13856–13863; e) L. N. Pridgen, L.
Snyder, J. Prol, J. Org. Chem. 1989, 54, 1523–1526;
f) M. C. Perry, A. N. Gillett, T. C. Law, Tetrahedron
Lett. 2012, 53, 4436–4439.
ˇ
dron Lett. 2007, 48, 4539–4541; b) D. Necas, M. Kotora,
I. Cꢅsarova, Eur. J. Org. Chem. 2004, 1280–1285; c) Y.
Hayashi, H. Shinokubo, K. Oshima, Tetrahedron Lett.
1998, 39, 63–66.
Adv. Synth. Catal. 2013, 355, 2197 – 2202
ꢁ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
asc.wiley-vch.de
2201

Samet Gꢀlak et al.
COMMUNICATIONS
[12] a) For more details of experimental and analytical data
and selected spectra, see the Supporting Information;
b) An in-situ reductive cross-coupling of 1, n-C10H21Br,
and magnesium failed. See also: W. M. Czaplik, M.
Mayer, S. Grupe, A. Jacobi von Wangelin, Pure Appl.
Chem. 2010, 82, 1545–1553; c) W. M. Czaplik, M.
Mayer, A. Jacobi von Wangelin, Angew. Chem. 2009,
121, 616–620; Angew. Chem. Int. Ed. 2009, 48, 607–610.
[13] a) J. K. Kochi, S. M. Neumann, J. Org. Chem. 1975, 40,
599–606; b) J. K. Kochi, M. Tamura, J. Organomet.
Chem. 1971, 31, 289–309; c) J. Kleimark, P.-F. Larsson,
P. Emamy, A. Hedstrçm, P.-O. Norrby, Adv. Synth.
Catal. 2012, 354, 448–456; d) J. Kleimark, A. Hedstrçm,
P.-F. Larsson, C. Johansson, P.-O. Norrby, ChemCat-
Chem 2009, 1, 152–161.
[14] I. Thomꢄ, A. Nijs, C. Bolm, Chem. Soc. Rev. 2012, 41,
979–987.
[15] a) M. Ogasawara, H. Ikeda, T. Nagano, T. Hayashi,
Org. Lett. 2001, 3, 2615–2617; b) L. A. Paquette, in: En-
cyclopedia of Reagents for Organic Synthesis, Vol. 2, 2nd
edn., Wiley, Chichester, 1995, pp 812–813.
Fernꢃndez, P.-H. Phua, J. Hoorn, L. Lefort, J. G. de V-
ries, Dalton Trans. 2010, 39, 8464–8471; c) R. B. Bed-
ford, M. Betham, D. W. Bruce, S. A. Davis, R. M. Frost,
M. Hird, Chem. Commun. 2006, 1398–1400.
[20] a) R. Jennerjahn, R. Jackstell, I. Piras, R. Franke, H.
Jiao, M. Bauer, M. Beller, ChemSusChem 2012, 5, 734–
739; b) M. Mayer, A. Welther, A. Jacobi von Wangelin,
ChemCatChem 2011, 3, 1567–1571.
[21] I. D. Gridnev, Coord. Chem. Rev. 2008, 252, 1798–1818.
[22] a) H.-S. Choi, R. L. Kuczkowski, J. Org. Chem. 1985,
50, 901–902; b) G. Vassilikogiannakis, M. Hatzimarina-
ki, M. Orfanopoulos, J. Org. Chem. 2000, 65, 8180–
8187.
[23] Radical mechanisms with alkyl halides: a) M. Guisꢃn-
Ceinos, F. Tato, E. BuÇuel, P. Calle, D. J. Cꢃrdenas,
Chem. Sci. 2013, 4, 1098–1104; b) T. Hatakeyama, T.
Hashimoto, K. K. A. D. S. Kathriarachchi, T. Zenmyo,
H. Seike, M. Nakamura, Angew. Chem. 2012, 124,
8964–8967; Angew. Chem. Int. Ed. 2012, 51, 8834–8837;
c) D. Noda, Y. Sunada, T. Hatakeyama, M. Nakamura,
H. Nagashima, J. Am. Chem. Soc. 2009, 131, 6078–
6079; mechanistic postulates of aryl halide cross-cou-
plings: d) G. Cahiez, V. Habiak, C. Duplais, A.
Moyeux, Angew. Chem. 2007, 119, 4442–4444; Angew.
Chem. Int. Ed. 2007, 46, 4364–4366; e) T. Hatakeyama,
S. Hashimoto, K. Ishizuka, M. Nakamura, J. Am.
Chem. Soc. 2009, 131, 11949–11963.
[16] J. R. Cabrero-Antonino, A. Leyva-Pꢄrez, A. Corma,
Adv. Synth. Catal. 2010, 352, 1571–1576.
[17] Iron-catalyzed ether cleavage reactions: D. Gꢆrtner, H.
Konnerth, A. Jacobi von Wangelin, Catal. Sci. Technol.
2013, DOI: 10.1039/C3CY00266G.
[18] a) K. Weber, E.-M. Schnçckelborg, R. Wolf, Chem-
CatChem 2011, 3, 1572–1577; b) A. Fꢀrstner, R.
Martin, H. Krause, G. Seidel, R. Goddard, C. W. Leh-
mann, J. Am. Chem. Soc. 2008, 130, 8773–8787.
[19] Reduction to Fe(0) species: a) A. Welther, M. Bauer,
M. Mayer, A. Jacobi von Wangelin, ChemCatChem
2012, 4, 1088–1093; b) C. Rangheard, C. de Juliꢃn
[24] a) J. K. Klassen, M. Selke, A. A. Sorensen, G. K. Yang,
in: Bonding Energetics in Organometallic Compounds,
(Ed.: T. J. Marks), ACS Symp. Ser. 1990, 428, 195–204;
b) D. L. CedeÇo, R. Sniatynsky, Organometallics 2005,
24, 3882–3890.
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Adv. Synth. Catal. 2013, 355, 2197 – 2202