Sequential ATRA/reductive cyclopropanation reactions with a ruthenium catalyst in the presence of manganese

Article abstract of DOI:10.1002/ejoc.201100175

Atom-transfer radical addition (ATRA) reactions of ethyl trichloroacetate, dichloromalononitrile, or diethyl 2,2-dichloromalonate with olefins followed by dechlorination have provided functionalized cyclopropanes in one step. The Ru^III complex

Full text of DOI:10.1002/ejoc.201100175

FULL PAPER
DOI: 10.1002/ejoc.201100175
Sequential ATRA/Reductive Cyclopropanation Reactions with a Ruthenium
Catalyst in the Presence of Manganese
Mariano A. Fernández-Zúmel,[a] Charlotte Buron,[a] and Kay Severin*[a]
Keywords: Cyclopropanation / Radical reactions / Reduction / Ruthenium / Manganese
Atom-transfer radical addition (ATRA) reactions of ethyl tri-
chloroacetate, dichloromalononitrile, or diethyl 2,2-dichloro-
malonate with olefins followed by dechlorination have pro-
vided functionalized cyclopropanes in one step. The RuIII
complex [Cp*RuCl2(PPh3)] was used as a catalyst precursor
and commercial Mn powder as reducing agent. Reactions
with the less activated substrate ethyl dichloroacetate gave
ATRA products with high turnover numbers but cycloprop-
anation was not observed.
Introduction
Transition-metal-catalyzed atom-transfer radical ad-
dition (ATRA) reactions allow the coupling of halogenated
compounds to olefins.[1,2] In recent years, catalysts and re-
action conditions have been optimized and nowadays it is
possible to perform highly efficient and selective ATRA re-
actions with a wide range of substrates.[1] Many transition
metals are able to catalyze ATRA reactions, but most stud-
ies have focused on copper[3] and ruthenium[4] complexes.
These complexes are particularly effective catalysts if they
are used in conjunction with reducing agents.[1a,5] Different
reagents have been used in this context, including magne-
sium powder,[6] the diazo compounds AIBN[7] and V-70,[8]
and ascorbic acid.[9] The role of these reagents is to convert
inactive CuII and RuIII complexes into active CuI and RuII
complexes.
We recently reported that the products of ATRA reac-
tions between olefins and activated dichloro compounds
can be converted into cyclopropanes by dechlorination with
Mg (Scheme 1).[10] The cyclopropanations can be per-
formed as one-pot-two-step reactions. First, a 1,3-dichlo-
ride is formed in an ATRA process with [Cp*RuCl2(PPh3)]
as the catalyst precursor and Mg as reducing agent. The
ATRA reaction is performed in a nonpolar organic solvent
such as toluene. Subsequent addition of the more polar
THF induces dechlorination to give the final cyclopropane.
An advantage of this cyclopropanation reaction is the
fact that functionalized cyclopropanes can be obtained
without the use of potentially problematic diazo com-
pounds. However, there are also limitations. The reaction
has to be performed in a two-step fashion because THF,
Scheme 1. Synthesis of cyclopropanes by sequential ATRA/dechlo-
rination reactions.[10]
which is required for the dechlorination step, is not compat-
ible with the ATRA reaction (Mg reacts with the chlori-
nated starting material if THF is added at the beginning of
the reaction). Furthermore, we encountered difficulties with
highly activated dichlorides such as Cl2C(CN)2 or
Cl3CCO2Et. These substrates undergo ATRA reactions but
fail to give cyclopropanes in acceptable yields. As a conse-
quence, it was not possible to synthesize cyclopropanes with
two electron-withdrawing groups in geminal positions. Be-
low we report that these limitations can be overcome if Mn
is used as a reducing agent instead of Mg. The new Mn-
based procedure allows one-step olefin cyclopropanation
reactions to be performed with highly activated dichlorides
to give difunctional cyclopropanes in good yields.
Results and Discussion
To address the shortcomings of our reported cycloprop-
anation procedure with Mg, we had to find an alternative
reducing agent with the following characteristics: 1) It
should be able to reduce the RuIII catalyst precursor, 2) it
should be largely inert towards the 1,1-dichloride starting
material, and 3) it should be able to promote the reductive
intramolecular coupling of the intermediate 1,3-dichloride.
[a] Institut des Sciences et Ingénierie Chimiques, École
Polytechnique Fédérale de Lausanne (EPFL),
1015 Lausanne, Switzerland
Fax: +41-21-693-9305
E-mail: kay.severin@epfl.ch
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ATRA/Reductive Cyclopropanation Reactions
Metallic manganese appeared to be an attractive choice. of the Ru/Mn catalyst system in these reactions was very
Mn is cheap, nontoxic, and it has a MII/M reduction poten- good and comparable to those of Ru catalysts used in com-
tial that is intermediate between that of Zn and Mg.[11] The bination with Mg.
functional group tolerance of organomanganese com-
Next we examined ATRA reactions with the more acti-
pounds is very good[12] and commercial Mn powder is not vated ethyl trichloroacetate using conditions similar to
very reactive towards organyl halides.[13,14] Mn0 has been those described above. As was observed for the dichlori-
employed as a selective stoichiometric reductant for reac- nated substrate, the ATRA product was formed rapidly.
tions with chromium,[15] titanocene,[16] and nickel com- However, the reaction did not stop at that stage but pro-
plexes.[17] Its use as a reducing agent in Ru-catalyzed ATRA ceeded to give the desired cyclopropane 1 (Scheme 3).
reactions is, to the best of our knowledge, unprecedented.
To test the suitability of Mn we first investigated the cou-
pling of ethyl dichloroacetate with styrene (Scheme 2). The
reaction was performed at room temperature with
[Cp*RuCl2(PPh3)] as catalyst precursor (0.1 mol-%) using
THF as the solvent. An excess of commercial Mn powder
(5 equiv. with respect to styrene) was added to the reaction
mixture. After only 1 h, we observed the clean formation
Scheme 3. ATRA/dechlorination reaction between ethyl trichloro-
acetate and styrene.
of the ATRA product ethyl 2,4-dichloro-4-phenylbutanoate
(86% yield). However, we did not observe the formation of Optimization of the reaction conditions revealed that a
the corresponding cyclopropane, even if the reaction mix- slightly elevated temperature of 60 °C is advantageous.
ture was heated at 60 °C.
Lowering the styrene concentration to 0.1 m and using
4 equiv. of ethyl trichloroacetate also improved the yield of
the cyclopropane. The low styrene concentration helps to
avoid the addition of a second olefin to the intermediate
1,3-dichloride, a process that we have recently investigated
in more detail.[18] The excess of the chlorinated substrate is
beneficial because Mn reacts to some extent with the highly
activated trichloro ester (GC analysis revealed the forma-
tion of sizeable amounts of a diester resulting from homo-
coupling of ethyl trichloroacetate).
By using the optimized conditions, we performed ATRA/
dechlorination reactions with ethyl trichloroacetate and dif-
ferent aromatic olefins, which gave the corresponding cyclo-
propanes 1–3 as a mixture of isomers in yields of around
70% (Table 2, entries 1–3). The isolated yields were lower
due to loss of product during chromatographic purification.
Ethyl 1-chloro-2-phenylcyclopropane-1-carboxylate (1)
has previously been made by Rh-catalyzed reaction of styr-
ene with ethyl α-chlorodiazoacetate, a reagent that decom-
poses rapidly at room temperature.[19] On the other hand, 1
has also been prepared in three steps from 1,1-dichloro-2-
phenylcyclopropane.[20] Our one-pot procedure based on
commercially available starting materials therefore repre-
sents an interesting synthetic alternative, even though the
isolated yield is not very high.
Scheme 2. ATRA reaction between ethyl dichloroacetate and styr-
ene.
The combination of [Cp*RuCl2(PPh3)] and Mn was
found to be a very potent catalyst system for ATRA reac-
tions of ethyl dichloroacetate. Lowering the Ru concentra-
tion to 0.02 mol-% still gave the coupling product in 78%
yield (Table 1, entry 1). The high turnover numbers indicate
that Mn is able to fulfill the dual role of reducing agent in
ATRA reactions: 1) Activation of the catalyst precursor
and 2) constant regeneration of the RuII catalyst from RuIII
complexes, which are formed as a result of termination re-
actions.[5] Mn alone or a mixture of Mn and MnCl2 did not
promote the ATRA reaction, which corroborates the cru-
cial role of the Ru catalyst.
Table 1. ATRA reactions between ethyl dichloroacetate and olefins
catalyzed by [Cp*RuCl2(PPh3)] in the presence of Mn.[a]
Olefin
Ru/Olefin
t [h]
Yield [%]
When ethyl trichloroacetate was replaced by dichloro-
malononitrile, the cyclopropane-1,1-dicarbonitriles 4–8
were obtained in isolated yields of 51–83% (Table 2, en-
tries 4–8). An increased catalyst loading of 5 mol-% was
employed in these reactions. Alternative ways of preparing
cyclopropane-1,1-dicarbonitriles involve the reductive cycli-
1
2
3
4
styrene
1:5000
1:5000
1:1000
1:250
24
48
24
24
78
93
83
83
p-chlorostyrene
α-methylstyrene
1-hexene
[a] Reaction conditions: [Cl2HCCO2Et] = 2.74 m, [olefin] = 1.37 m,
[Mn] = 5 equiv. with respect to the olefin, THF, room temp. The
yield was determined by 1H NMR spectroscopy. The conversion of zation of an appropriate allylic bromide,[21] the photoiniti-
the olefin was quantitative in all cases.
ated addition of bromomalonitrile to an olefin followed by
cyclizative dehydrobromination,[22] the PhI(OAc)2-mediated
We also examined the ATRA reaction of ethyl dichlo- oxidative addition of malononitrile to olefins,[23] and the
roacetate with other olefins. By using between 0.4 and indium-mediated reductive coupling of dibromomalonitrile
0.02 mol-% Ru, we were able to obtain the corresponding with olefins.[24] The last two methods are one-step pro-
1,3-dichlorides in good yields (Table 1). The performance cedures but the cyclopropanes are obtained in poor yields.
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M. A. Fernández-Zúmel, C. Buron, K. Severin
FULL PAPER
Table 2. ATRA/dechlorination reactions catalyzed by [Cp*RuCl2(PPh3)] in the presence of Mn.[a]
[a] Reaction conditions: [Cl2CRRЈ] = 0.40 m, [olefin] = 0.10 m, [Ru] = 1.0 mm (1.0 mol-%), [Mn] = 5 equiv. with respect to the olefin,
THF, 60 °C. [b] Crude yields determined by GC. The isolated yields are given in parentheses. [c] Use of 2 mol-% catalyst. [d] Use of
5 mol-% catalyst. [e] [Cl2C(CO2Et)2] = 0.25 m.
We have also investigated the reaction of styrene with by GC) after 3 h (Scheme 4). These results show that the
diethyl 2,2-dichloromalonate. The corresponding cycloprop- cyclization step can be performed without the Ru catalyst.
ane 9 was obtained in 66% yield (Table 2, entry 9). Gemi- It is thus unlikely that the Ru complex is involved in the
nal cyclopropanedicarboxylates such as 9 are valuable pre- dechlorination. However, it may contribute to the activation
cursors for a variety of reactions.[25] They are most often of Mn, which occurs during the ATRA step.
prepared by the reaction of an alkylidenemalonate with di-
methylsulfoxonium or dimethylsulfonium methylides.[25a,26]
Other methodologies involve the metal-catalyzed reactions
of an olefin with diazomalonates[27] or iodonium ylides.[28]
To establish the role of the Ru complex in the dechlorina-
tion process, we studied the cyclization of the isolated
ATRA adduct ethyl 2,2,4-trichloro-4-phenylbutanoate. The
reaction with 10 equiv. of Mn in THF did not give detect-
able amounts of cyclopropane 1, even not after 24 h. How-
ever, when the reducing agent was preactivated by stirring
it for 2 min with ClSiMe3 (0.1 equiv.) and PbCl2
(0.0025 equiv., both relative to Mn),[13] the corresponding
Scheme 4. The dechlorination reaction of ethyl 2,2,4-trichloro-4-
cyclization product was obtained in 81% yield (determined phenylbutanoate requires activated Mn powder.
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Eur. J. Org. Chem. 2011, 2272–2277

ATRA/Reductive Cyclopropanation Reactions
signed in analogy to the literature report.[20] The NMR spectro-
scopic data of the main product (cis isomer) is as follows: 1H NMR
(CDCl3, 400 MHz): δ = 1.36 (t, J = 7.2 Hz, 3 H, CH3), 1.70–1.73
(m, 1 H, CH2), 2.15–2.19 (m, 1 H, CH2), 3.06 (dd, J = 8.9, 9.9 Hz,
1 H, ArCH), 4.28 (m, 2 H, OCH2), 7.03–7.22 (m, 4 H, aro-
matic) ppm. 13C NMR (CDCl3, 100 MHz): δ = 14.1 (CH3), 23.7
(CH2), 32.9 (ArCH), 44.7 (CCl), 62.7 (OCH2), 115.0–131.1 (m, aro-
Conclusions
Transition-metal-catalyzed ATRA reactions are best per-
formed in the presence of reducing agents.[5] We have shown
that commercial Mn powder is a potent reagent in this con-
text. The Ru-catalyzed coupling of ethyl dichloroacetate to
styrene, for example, can be achieved with only 0.02 mol-%
of Ru. An important advantage of Mn is the possibility
of performing sequential ATRA/dechlorination reactions[29]
with highly activated dichloro compounds such as ethyl tri-
chloroacetate, dichloromalononitrile, or diethyl 2,2-dichloro-
malonate. These reactions provide synthetically interesting
cyclopropanes in one step from easily available starting ma-
terials.
matic), 163.2 (d,
J = 44.8 Hz, CF), 170.1 (COOEt) ppm.
C12H12O2ClF·1͞3H2O (248.682): calcd. C 57.96, H 5.13; found C
57.94, H 5.02.
Ethyl 1-Chloro-2-(4-methoxyphenyl)cyclopropane-1-carboxylate (3):
Flash chromatography on silica gel, hexane/ethyl acetate = 6:1. The
product was obtained as a mixture of two diastereoisomers (ratio
from 1H NMR: cis/trans = 2:1). The assignment of the diastereoiso-
mers was performed in analogy to the literature report.[20] 1H NMR
(CDCl3, 400 MHz): δ = 0.96 (t, J = 7.2 Hz, 3 H, CH3, trans), 1.36
(t, J = 7.0 Hz, 3 H, CH3, cis), 1.70–1.78 (m, 2 H, CH2, cis + trans),
2.15–2.19 (m, 2 H, CH2, cis + trans), 2.96–3.06 (m, 2 H, ArCH, cis
+ trans), 3.85–3.97 (m, 2 H, OCH2, trans), 4.26–4.32 (m, 2 H,
OCH2, cis), 6.82–7.20 (m, 8 H, aromatic, 2 H, cis + trans) ppm.
13C NMR (CDCl3, 100 MHz): δ = 13.8 (CH3), 14.2 (CH3), 21.9
(CH2), 23.6 (CH2), 32.2 (ArCH), 36.3 (ArCH), 44.2 (CCl), 45.0
(CCl), 55.2 (OCH3), 61.9 (OCH2), 62.6 (OCH2), 113.5, 113.6,
126.4, 126.5, 130.0, 130.5 (aromatic), 158.9 (COCH3), 159.0
(COCH3), 167.4 (COOEt), 170.3 (COOEt) ppm. Due to the overlap
of peaks in the 13C NMR spectrum, the correct number of peaks
could not be observed. C13H15O3Cl·1͞3H2O (260.718): C 59.89, H
6.06; C 59.73, H 6.05.
Experimental Section
General: All reactions were performed under dry nitrogen using a
glovebox. The solvents and liquid substrates were distilled from
appropriate drying agents and stored under nitrogen. The olefinic
substrates were stored at a temperature of –18 °C. The solvents and
chlorinated esters as well as the solids were kept at room tempera-
ture. The catalyst precursor [Cp*RuCl2(PPh3)][30] and the substrate
[31]
Cl2C(CO2Et)2
were synthesized according to literature pro-
cedures. Mn powder (140–325 mesh, 99.6%) was purchased from
AlfaAesar. The 1H and 13C NMR spectra were recorded with a
Bruker Avance DPX 400 spectrometer with the residual solvents as
internal standards. All spectra were recorded at room temperature.
Column chromatography was performed using silica gel 60 (230–
400 mesh, 0.04–0.063 nm) from Fluka. Plates coated with silica gel
60 F245 from Merck were used for thin-layer chromatography. Ele-
mental analyses were performed with a EA 1110 CHN instrument.
Cyclopropanes 4–9: Flash chromatography on silica gel, hexane/
ethyl acetate = 4:1 (4–8) or 7:1 (9). The spectroscopic data for the
products correspond to those previously described in the litera-
ture.[22,33–36]
General Procedure for the ATRA Reactions: The desired amount of
a stock solution of complex 1 in THF was added to a 2.0 mL vial
that contained Mn powder (370 mg). A stock solution of the chlori-
nated compound, the olefin, and mesitylene as an internal standard
was added to the vial and the total volume was increased to
1000 μL with THF ([olefin] = 1.38 m, [chlorinated compound] =
2.76 m, [internal standard] = 138 mm). The resulting solution was
stirred at room temperature. After the given time, a sample (20 μL)
was removed from the reaction mixture, diluted with CDCl3
Acknowledgments
This work was supported by the Swiss National Science Founda-
tion and by the École Polytechnique Fédérale de Lausanne (EPFL).
[1]
a) W. T. Eckenhoff, T. Pintauer, Catal. Rev. 2010, 52, 1–59; b)
T. Pintauer, K. Matyjaszewski, Chem. Soc. Rev. 2008, 37, 1087–
1097; c) K. Severin, Curr. Org. Chem. 2006, 10, 217–224; d) L.
Delaude, A. Demonceau, A. F. Noels, Top. Organomet. Chem.
2004, 11, 155–171; e) H. Nagashima in Ruthenium in Organic
Synthesis (Ed.: S.-I. Murahashi), Wiely-VCH, Weinheim, 2004,
pp. 333–343; f) A. J. Clark, Chem. Soc. Rev. 2002, 31, 1–11; g)
K. I. Kobrakov, A. V. Ivanov, Chem. Heterocycl. Compd. 2001,
37, 529–539; h) R. A. Gossage, L. A. van de Kuil, G.
van Koten, Acc. Chem. Res. 1998, 31, 423–431; i) J. Iqbal, B.
Bhatia, N. K. Nayyar, Chem. Rev. 1994, 94, 519–564; j) F. Min-
isci, Acc. Chem. Res. 1975, 8, 165–171.
1
(500 μL), and analyzed by H NMR spectroscopy.
General Procedure for the Sequential ATRA/Reductive Cyclopropan-
ation Reactions: Mn powder (10 equiv.) and THF were added to a
flask containing the desired amount of the Ru catalyst. The olefin
(2.0 mmol) and the chlorinated substrate (8.0 mmol, 4 equiv.) were
added ([olefin]final = 0.10 m) and the mixture was stirred at 60 °C.
After the given time, the crude reaction mixture was diluted with
hexane, filtered through kieselgur, and the solvent was removed
under reduced pressure. The product was purified by flash
chromatography.
[2]
[3]
For pioneering studies, see: a) M. S. Kharasch, E. V. Jensen,
W. H. Urry, Science 1945, 102, 128–128; b) M. S. Kharasch,
W. H. Urry, E. V. Jensen, J. Am. Chem. Soc. 1945, 67, 1626–
1626.
For selected examples, see: a) J. Muñoz-Molina, T. R. Belder-
raín, P. J. Pérez, Inorg. Chem. 2010, 49, 642–645; b) F. Ghelfi,
F. Roncaglia, M. Pattarozzi, V. Giangiordano, G. Petrillo, F.
Sancassan, A. F. Parsons, Tetrahedron 2009, 65, 10323–10333;
c) M. Pattarozzi, F. Roncaglia, V. Giangiordano, P. Davoli, F.
Prati, F. Ghelfi, Synthesis 2010, 694–700; d) A. J. Clark, P. Wil-
son, Tetrahedron Lett. 2008, 49, 4848–4850; e) J. A. Bull, M. G.
Ethyl 1-Chloro-2-phenylcyclopropane-1-carboxylate (1): Flash
chromatography on silica gel, hexane/ethyl acetate = 7:1. The prod-
uct was obtained as a mixture of two diastereoisomers (ratio from
1H NMR: cis/trans = 6:1). The spectroscopic data for the product
correspond to those previously described in the literature.[32]
Ethyl 1-Chloro-2-(4-fluorophenyl)cyclopropane-1-carboxylate (2):
Flash chromatography on silica gel, hexane/ethyl acetate = 6:1. The
product was obtained as a mixture of two diastereoisomers (ratio
from 1H NMR: cis/trans = 7:1). The diastereoisomers were as-
Eur. J. Org. Chem. 2011, 2272–2277
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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2275

M. A. Fernández-Zúmel, C. Buron, K. Severin
FULL PAPER
Hutchings, C. Luján, P. Quayle, Tetrahedron Lett. 2008, 49,
1352–1356; f) R. N. Ram, N. Kumar, Tetrahedron Lett. 2008,
49, 799–802; g) J. A. Bull, M. G. Hutchings, P. Quayle, Angew.
Chem. 2007, 119, 1901; Angew. Chem. Int. Ed. 2007, 46, 1869–
1872; h) A. J. Clark, J. V. Geden, S. Thom, P. Wilson, J. Org.
Chem. 2007, 72, 5923–5926; i) J. M. Muñoz-Molina, A. Cabal-
lero, M. M. Díaz-Requejo, S. Trofimenko, T. R. Belderraín,
P. J. Pérez, Inorg. Chem. 2007, 46, 7725–7730; j) C. V. Stevens,
E. Van Meenen, K. G. R. Masschelein, Y. Eeckhout, W.
Hooghe, B. DЈhondt, V. N. Nemykin, V. V. Zhdankin, Tetrahe-
dron Lett. 2007, 48, 7108–7111.
[13]
Commercial Mn is protected by an oxide layer, see: K. Takai,
T. Ueda, T. Hayashi, T. Moriwake, Tetrahedron Lett. 1996, 37,
7049–7052.
II
[14]
[15]
Activated Mn*, which is prepared by reduction of Mn salts,
can react with a variety of organyl halides (see ref.[12]).
For selected examples, see: a) J. Y. Kang, B. T. Connell, J. Am.
Chem. Soc. 2010, 132, 7826–7827; b) K. C. MacLeod, J. L.
Conway, B. O. Patrick, K. M. Smith, J. Am. Chem. Soc. 2010,
132, 17325–17334; c) K. C. MacLeod, B. O. Patrick, K. M.
Smith, Organometallics 2010, 29, 6639–6641; d) K. Namba, J.
Wang, S. Cui, Y. Kishi, Org. Lett. 2005, 7, 5421–5424; e) M.
Lombardo, S. Morganti, S. Licciulli, C. Trombini, Synlett 2003,
43–46; f) A. Fürstner, N. Shi, J. Am. Chem. Soc. 1996, 118,
12349–12357; g) A. Fürstner, N. Shi, J. Am. Chem. Soc. 1996,
118, 2533–2534.
[4]
For selected examples, see: a) R. P. Nair, T. H. Kim, B. J. Frost,
Organometallics 2009, 28, 4681–4688; b) R. J. Lundgren, M. A.
Rankin, R. McDonald, M. Stradiotto, Organometallics 2008,
27, 254–258; c) B. Dutta, E. Solari, R. Scopelliti, K. Severin,
Organometallics 2008, 27, 423–429; d) Y. Borguet, A. Richel,
S. Delfosse, A. Leclerc, L. Delaude, A. Demonceau, Tetrahe-
dron Lett. 2007, 48, 6334–6338; e) Y. Motoyama, S. Hanada,
K. Shimamoto, H. Nagashima, Tetrahedron 2006, 62, 2779–
2788; f) L. Quebatte, E. Solari, R. Scopelliti, K. Severin, Orga-
nometallics 2005, 24, 1404–1406; g) Y. Motoyama, S. Hanada,
S. Niibayashi, K. Shimamoto, N. Takaoka, H. Nagashima, Tet-
rahedron 2005, 61, 10216–10226; h) L. Quebatte, M. Haas, E.
Solari, R. Scopelliti, Q. T. Nguyen, K. Severin, Angew. Chem.
2005, 117, 1108; Angew. Chem. Int. Ed. 2005, 44, 1084–1088; i)
L. Quebatte, R. Scopelliti, K. Severin, Eur. J. Inorg. Chem.
2005, 3353–3358; j) L. Quebatte, R. Scopelliti, K. Severin, An-
gew. Chem. 2004, 116, 1546; Angew. Chem. Int. Ed. 2004, 43,
1520–1524; k) B. T. Lee, T. O. Schrader, B. Martín-Matute,
C. R. Kauffman, P. Zhang, M. L. Snapper, Tetrahedron 2004,
60, 7391–7396; l) O. Tutusaus, S. Delfosse, A. Demonceau,
A. F. Noels, C. Viñas, F. Teixidor, Tetrahedron Lett. 2003, 44,
8421–8425; m) O. Tutusaus, C. Viñas, R. Núñez, F. Teixidor,
A. Demonceau, S. Delfosse, A. F. Noels, I. Mata, E. Molins, J.
Am. Chem. Soc. 2003, 125, 11830–11831; n) B. de Clercq, F.
Verpoort, Tetrahedron Lett. 2002, 43, 4687–4690; o) F. Simal,
L. Wlodarczak, A. Demonceau, A. F. Noels, Eur. J. Org. Chem.
2001, 14, 2689–2695; p) F. Simal, L. Wlodarczak, A. De-
monceau, A. F. Noels, Tetrahedron Lett. 2000, 41, 6071–6074.
T. Pintauer, Eur. J. Inorg. Chem. 2010, 2449–2460.
a) M. A. Fernández-Zúmel, K. Thommes, G. Kiefer, A. Sienk-
iewicz, K. Pierzchala, K. Severin, Chem. Eur. J. 2009, 15,
11601–11607; b) J. M. Muñoz-Molina, T. R. Belderraín, P. J.
Pérez, Adv. Synth. Catal. 2008, 350, 2365–2372; c) J. Wolf, K.
Thommes, O. Briel, R. Scopelliti, K. Severin, Organometallics
2008, 27, 4464–4474; d) K. Thommes, B. Içli, R. Scopelliti, K.
Severin, Chem. Eur. J. 2007, 13, 6899–6907.
a) M. N. C. Balili, T. Pintauer, Inorg. Chem. 2010, 49, 5642–
5649; b) C. Ricardo, T. Pintauer, Chem. Commun. 2009, 3029–
3031; c) M. N. C. Balili, T. Pintauer, Inorg. Chem. 2009, 48,
9018–9026; d) W. T. Eckenhoff, S. T. Garrity, T. Pintauer, Eur.
J. Inorg. Chem. 2008, 563–571; e) W. T. Eckenhoff, T. Pintauer,
Inorg. Chem. 2007, 46, 5844–5846; f) L. Quebatte, K.
Thommes, K. Severin, J. Am. Chem. Soc. 2006, 128, 7440–
7441.
[16]
For selected examples, see: a) A. Gansäuer, M. Otte, L. Shi, J.
Am. Chem. Soc. 2011, DOI: 10.1021/ja109362m; b) A. Gan-
säuer, L. Shi, M. Otte, J. Am. Chem. Soc. 2010, 132, 11858–
11859; c) M. Paradas, A. G. Campaña, R. E. Estévez, L. A.
de Cienfuegos, T. Jiménez, R. Robles, J. M. Cuerva, J. E. Oltra,
J. Org. Lett. 2009, 74, 3616–3619; d) P. Wipf, J. P. Maciejewski,
Org. Lett. 2008, 10, 4383–4386; e) A. Gansäuer, C.-A. Fan, F.
Keller, J. Keil, J. Am. Chem. Soc. 2007, 129, 3484–3485; f) A. F.
Barrero, M. M. Herrador, J. F. Quílez del Moral, P. Arteaga,
M. Akssira, F. El Hanbali, J. F. Arteaga, H. R. Diéguez, E. M.
Sánchez, J. Org. Chem. 2007, 72, 2251–2254; g) A. Gansäuer,
H. Blum, M. Pierobon, J. Am. Chem. Soc. 1998, 120, 12849–
12859.
a) D. A. Everson, R. Shrestha, D. J. Weix, J. Am. Chem. Soc.
2010, 132, 920–921; b) M. R. Prinsell, D. A. Everson, D. J.
Weix, Chem. Commun. 2010, 46, 5743–5745.
K. Thommes, M. A. Fernández-Zúmel, C. Buron, A. Godinat,
R. Scopelliti, K. Severin, Eur. J. Org. Chem. 2011, 249–255.
H. T. Bonge, B. Pintea, T. Hansen, Org. Biomol. Chem. 2008,
6, 3670–3672.
T. Nagano, J. Motoyoshiya, A. Kakehi, Y. Nishii, Org. Lett.
2008, 10, 5453–5456.
X.-Q. Zhu, H.-Y. Wang, J.-S. Wang, Y.-C. Liu, J. Org. Chem.
2001, 66, 344–347.
a) J.-B. Kim, I. Cho, Tetrahedron 1997, 53, 15157–15166; b)
P. Boldt, L. Schulz, U. Klinsmann, H. Köster, W. Thielecke,
Tetrahedron 1970, 26, 3591–3615.
A. S. Biland, S. Altermann, T. Wirth, ARKIVOC 2003, 6, 164–
169.
S. Araki, Y. Butsugan, J. Chem. Soc., Chem. Commun. 1989,
1286–1287.
a) A. O. Chagarovskiy, O. A. Ivanova, E. R. Rakhmankulov,
E. M. Budynina, I. V. Trushkov, M. Y. Melnikov, Adv. Synth.
Catal. 2010, 352, 3179–3184; b) J.-P. Qu, C. Deng, J. Zhou, X.-
L. Sun, Y. Tang, J. Org. Chem. 2009, 74, 7684–7689; c) J. Fang,
J. Ren, Z. Wang, Tetrahedron Lett. 2008, 49, 6659–6662; d)
O. A. Ivanova, E. M. Budynina, Y. K. Grishin, I. V. Trushkov,
P. V. Verteletskii, Eur. J. Org. Chem. 2008, 5329–5335; e) O. A.
Ivanova, E. M. Budynina, Y. K. Grishin, I. V. Trushkov, P. V.
Verteletskii, Angew. Chem. 2008, 120, 1123; Angew. Chem. Int.
Ed. 2008, 47, 1107–1110; f) Y.-B. Kang, X.-L. Sung, Y. Tang,
Angew. Chem. 2007, 119, 3992; Angew. Chem. Int. Ed. 2007,
46, 3918–3921.
E. J. Corey, M. Chaykovsky, J. Am. Chem. Soc. 1965, 87, 1353–
1364.
F. González-Bobes, M. D. B. Fenster, S. Kiau, L. Kolla, S. Kol-
otuchin, M. Soumeillant, Adv. Synth. Catal. 2008, 350, 813–
816.
S. R. Goudreau, D. Marcoux, A. B. Charette, J. Org. Chem.
2009, 74, 470–473.
For examples of sequential or tandem reactions involving a Ru-
catalyzed radical addition, see: a) Y. Borguet, X. Sauvage, G.
Zaragoza, A. Demonceau, L. Delaude, Beilstein J. Org. Chem.
2010, 6, 1167–1173; b) B. A. Seigal, C. Fajardo, M. L. Snapper,
J. Am. Chem. Soc. 2005, 127, 16329–16332; c) B. Schmidt, M.
[17]
[18]
[19]
[20]
[21]
[22]
[5]
[6]
[23]
[24]
[25]
[7]
[8]
[9]
T. Pintauer, W. T. Eckenhoff, C. Ricardo, M. N. C. Balili, A. B.
Biernesser, S. T. Noonan, M. T. Taylor, Chem. Eur. J. 2009, 15,
38–41.
a) R. Casolari, F. Felluga, V. Frenna, F. Ghelfi, U. M. Pagnoni,
A. F. Parsons, D. Spinelli, Tetrahedron 2011, 67, 408–416; b)
M. J. W. Taylor, W. T. Eckenhoff, T. Pintauer, Dalton Trans.
2010, 39, 11475–11482.
[26]
[27]
[10]
[11]
[12]
K. Thommes, G. Kiefer, R. Scopelliti, K. Severin, Angew.
Chem. 2009, 121, 8259; Angew. Chem. Int. Ed. 2009, 48, 8115–
8119.
[28]
[29]
Electrochemical redox potential for Mn+2/Mn0 is –1.03 V, see:
Handbook of Chemistry and Physics, 62nd ed., CRC, Boca Ra-
ton, FL, 1982.
J. M. Concellón, H. Rodríguez-Solla, V. del Amo, Chem. Eur.
J. 2008, 14, 10184–10191.
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www.eurjoc.org
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2011, 2272–2277

ATRA/Reductive Cyclopropanation Reactions
Pohler, J. Organomet. Chem. 2005, 690, 5552–5555; d) C. W.
Bielawski, J. Louie, R. H. Grubbs, J. Am. Chem. Soc. 2000,
122, 12872–12873.
[33] Y.-C. Liu, B. Li, Q.-X. Guo, Tetrahedron 1995, 51, 9671–9680.
[34] L. Töke, Z. Hell, G. T. Szabó, G. Tótk, M. Bihari, A. Rocken-
bauer, Tetrahedron 1993, 49, 5133–5146.
[35] P. Boldt, L. Schulz, U. Klinsmann, H. Köster, W. Thielecke,
Tetrahedron 1970, 26, 3951–3615.
[36] C. G. Hamaker, J.-P. Djukic, D. A. Smith, L. K. Woo, Organo-
metallics 2001, 20, 5189–5199.
[30] T. Arliguie, C. Border, B. Chaudret, J. Devillers, R. Poilblanc,
Organometallics 1989, 8, 1308–1314.
[31] G. H. Hakimelahi, G. Just, Tetrahedron Lett. 1979, 20, 3643–
3644.
[32] T. Nagano, J. Motoyoshiya, A. Kakehi, Y. Nishii, Org. Lett.
2008, 10, 5453–5456.
Received: February 7, 2011
Published Online: March 8, 2011
Eur. J. Org. Chem. 2011, 2272–2277
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
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