3 (a) N. Suzuki, H. Tahara, D. Ishihara, H. Danjo and T. Mimura,
PCT Int. Appl., WO 2010024420, 2010; (b) S. Maetani,
T. Fukuyama, N. Suzuki, D. Ishihara and I. Ryu, Organometallics,
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4 D. Vogt, in Applied Homogeneous Catalysis with Organometallic
Compounds, ed. B. Cornils and W. A. Herrmann, Wiley-VCH,
Weinheim, 1996, p. 245.
5 (a) C. Bolm, J. Legros, J. L. Paih and L. Zani, Chem. Rev., 2004,
104, 6217; (b) S. Enthaler, K. Junge and M. Beller, Angew. Chem., Int.
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Chem. Res., 2008, 41, 1500; (e) W. M. Czaplik, M. Mayer,
J. Cvengros and A. J. von Wangelin, ChemSusChem, 2009, 2, 396.
6 For selected examples of iron-catalyzed reduction, see:
(a) S. C. Bart, E. Lobkovsky and P. J. Chirik, J. Am. Chem.
Soc., 2004, 126, 13794; (b) C. P. Casey and H. Guan, J. Am. Chem.
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K. Junge and M. Beller, Chem.–Asian J., 2006, 1, 598;
(d) H. Nishiyama and A. Furuta, Chem. Commun., 2007, 760.
7 For selected examples of iron-catalyzed oxidation, see: (a) J. Legros
and C. Bolm, Angew. Chem., Int. Ed., 2003, 42, 5487; (b) M. R.
Bukowski, P. Comba, A. Lienke, C. Limberg, C. L. de Laorden,
R. Mas-Ballest_e, M. Merz and L. Que, Jr., Angew. Chem., Int. Ed.,
2006, 45, 3446; (c) M. S. Chen and M. C. White, Science, 2007,
318, 783; (d) F. G. Gelalcha, B. Bitterlich, G. Anilkumar, M. K. Tse
and M. Beller, Angew. Chem., Int. Ed., 2007, 46, 7293; (e) M. S. Chen
and M. C. White, Science, 2010, 327, 566.
8 For selected examples of iron-catalyzed cross-coupling reactions,
see: (a) A. Furstner, A. Leitner, M. Mendez and H. Krause, J. Am.
Chem. Soc., 2002, 124, 13856; (b) M. Nakamura, S. Ito, K. Matsuo
and E. Nakamura, Synlett, 2005, 1794; (c) M. Carril, A. Correa
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C. M. R. Volla and P. Vogel, Adv. Synth. Catal., 2008, 350, 2859;
(e) T. Hatakeyama, T. Hashimoto, Y. Kondo, Y. Fujiwara,
H. Seike, H. Takaya, Y. Tamada, T. Ono and M. Nakamura,
J. Am. Chem. Soc., 2010, 132, 10674.
9 For selected examples of iron-catalyzed carbonylation, see:
(a) K. M. Driller, H. Klein, R. Jackstell and M. Beller, Angew.
Chem., Int. Ed., 2009, 48, 6041; (b) K. M. Driller,
S. Prateeptongkum, R. Jackstell and M. Beller, Angew. Chem.,
Int. Ed., 2011, 50, 537; (c) M. Pizzetti, A. Russo and E. Petricci,
Chem.–Eur. J., 2011, 17, 4523.
10 (a) G. Booth and J. Chat, J. Chem. Soc., 1962, 2099; (b) C. Roger,
P. Hamon, L. Toupet, H. Rabaa, J.-Y. Saillard, J.-R. Hamon and
C. Lapinte, Organometallics, 1991, 10, 1045.
11 We examined the decarbonylation of 1a using FeCl2 with high
purity (99.998%) instead of the standard FeCl2 (98%). As a result,
no change in the product yield and selectivity was observed. In the
absence of FeCl2, the reaction did not occur. From these results,
we believe that the decarbonylation reaction is catalyzed by iron,
not affected by the trace amount of other metals contaminated in
FeCl2 and KI (see ESIw).
Scheme 1 Possible reaction mechanism.
which then undergoes b-hydride elimination to give a-olefins 2
with the generation of the iron hydride complex D. The active
catalytic species A is regenerated by the reductive elimination
of 1 and/or acetic acid from D.17 Iron hydride species D may
catalyze isomerization of the initially formed 2 to produce
internal olefins 3.
In summary, we have demonstrated a decarbonylation
reaction of aliphatic carboxylic acids to give olefins catalyzed
by an iron catalyst. High a-olefin preference was achieved by
using a combination of a bidentate ligand, DPPPent, and CO.
We believe that precious transition metal complexes are no
more indispensable to achieve the transformation. Further
studies to clarify the detailed mechanism as well as to extend
this chemistry in organic synthesis are currently under investi-
gation in our laboratory.
This work was supported by a Grant-in-Aid for Scientific
Research on Innovative Areas (No. 2105) from MEXT Japan
and a Grant-in-Aid for Scientific Research (B) from JSPS.
12 We also examined the reaction of an aromatic carboxylic acid,
2-naphthalenecarboxylic acid under standard conditions, which
gave a low yield of naphthalene via decarboxylation.
13 The reaction of stearic acid (1a) with Ac2O at 250 1C for 30 min
gave a mixture of stearyl acetate and stearic acid anhydride in 77%
yield (19/81). In the absence of Ac2O, only a small amount of acid
anhydrides was formed.
Notes and references
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Angew. Chem., Int. Ed., 2000, 39, 2206; (b) M. Eissen,
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2 (a) R. H. Prince and K. A. Raspin, Chem. Commun., 1966, 156;
(b) D. M. Fenton, U. S. Patent, 3,530,198, 1970; (c) T. A. Foglia
and P. A. Barr, J. Am. Oil Chem. Soc., 1976, 53, 737;
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14 The IR spectrum of a crude reaction mixture showed three
absorption bands due to metal carbonyl complexes (1941, 2001,
2069 cmꢀ1), Although the structure are not clear at this stage, the
fact that pressurized CO enhanced catalytic activity implies that
an iron-carbonyl species generated in situ act as active catalyst species.
15 Decarbonylation of thioanhydrides by iron complex, see:
B. M. Trost and F. Chen, Tetrahedron Lett., 1971, 12, 2603.
16 Decarbonylation of esters by iron complex, see: R. J. Trovitch,
E. Lobkovsky, M. W. Bouwkamp and P. J. Chirik, Organometal-
lics, 2008, 27, 6264.
17 The decarbonylation reaction of stearic anhydride proceeded
smoothly to give heptadecenes and stearic acid (1a) in 94% and
93% yields, respectively, which suggests that the reaction involves
the elimination of carboxylic acid.
c
2554 Chem. Commun., 2012, 48, 2552–2554
This journal is The Royal Society of Chemistry 2012