COMMUNICATIONS
Catal. 1997, 120, L9 ± L11; d) V. Dufaud, J. Thivolle-Cazat, J.-M.
Basset, J. Chem. Soc. Chem. Commun. 1990, 426 ± 427; e) R. J. Perry,
B. D. J. Wilson, J. Org. Chem. 1996, 61, 7482 ± 7485.
Experimental Section
General procedure for the alkoxycarbonylation of chloroarenes: the
corresponding chloroarene (7 mmol), n-butanol (14 mL), [PdCl2(PhCN)2]
(13.4 mg, 0.035 mmol, 0.5 mol%), and ligand 4 (84.9 mg, 0.140 mmol,
2 mol%) were added to a Schlenk flask under argon (orange solution).
Sodium carbonate (2.226 g, 21 mmol, 3 equiv) and molecular sieves (4 ,
ca. 3 g) were added to the reaction autoclave. Following evacuation and
replacement with argon (three cycles) the reaction mixture was transferred
with a PVC hose (Æ ꢂ 2 mm) under a slight excess pressure of argon from
the Schlenk flask into the autoclave. The autoclave was closed and heated
to the reaction temperature (1458C). The reaction pressure (1 bar CO) was
held constant by means of a CO reservoir, connected to the autoclave by a
pressure regulator. After 16 h reaction time the autoclave was cooled to
room temperature and the yellow orange mixture diluted with dichloro-
methane (70 mL). After washing with water (70 mL) the aqueous phase
was extracted with dichloromethane (2 Â 20 mL), and the combined
organic phases were dried over magnesium sulfate, filtered, and concen-
trated under reduced pressure. The crude product was then purified by
column chromatography (silica gel, EtOAc/hexane).
[9] a) W. Mägerlein, M. Beller, A. F. Indolese, J. Mol. Catal. 2000, 156,
213.
[10] M. Beller, W. Mägerlein, A. Indolese, C. Fischer, Synthesis 2001,
1098 ± 1109.
[11] a) A. Togni, C. Breutel, A. Schnyder, F. Spindler, H. Landert, A.
Tijani, J. Am. Chem. Soc. 1994, 116, 4062 ± 4066; b) T. Hayashi in
Ferrocenes (Eds.: A. Togni, T. Hayashi), VCH, Weinheim, 1995,
pp. 105 ± 142; c) A. Togni, Chimia 1996, 50, 86 ± 93.
[12] a) F. Spindler, H.-U. Blaser, Enantiomer 1999, 4, 557 ± 568; b) H.-U.
Blaser, H. P. Buser, K. Coers, R. Hanreich, H.-P. Jalett, E. Jelsch, B.
Pugin, H.-D. Schneider, F. Spindler A. Wegmann, Chimia 1999, 53,
275 ± 280.
[13] In a long reaction time experiment on the alkoxycarbonylation of
chlorobenzene with 5 mol% Pd catalyst
a conversion of 48%
(selectivity 91%) was reached after 5 days even at
a reaction
temperature of 908C.
[14] A P:Pd ratio of 80:1 was chosen for these experiments to maintain a
ligand concentration 2 mol%. In earlier work on carbonylation
reactions we showed that for the stabilization of the Pd catalyst the
ligand concentration and not the ligand:palladium ratio is important.[9]
Received: March 20, 2001 [Z16812]
[1] a) J. Tsuji, Palladium Reagents and Catalysts: Innovations in Organic
Synthesis, Wiley, Chichester, 1995; b) F. Diederich, P. J. Stang, Metal-
Catalyzed Cross-Coupling Reactions, Wiley-VCH, Weinheim, 1998;
c) M. Beller, C. Bolm, Transition Metals for Organic Synthesis, Wiley-
VCH, Weinheim, 1998.
[2] a) A. Schoenberg, I. Bartoletti, R. F. Heck, J. Org. Chem. 1974, 39,
3318 ± 3326; b) S. A. Vinogradov, D. F. Wilson, Tetrahedron Lett. 1998,
39, 8935 ± 8938.
[3] a) H. M. Colquhoun, D. J. Thompson, M. V. Twigg, Carbonylation,
Direct Synthesis of Carbonyl Compounds, Plenum, New York, 1991;
b) M. Beller in Applied Homogeneous Catalysis with Organometallic
Compounds, Vol. 2 (Eds.: B. Cornils, W. A. Herrmann), VCH,
Weinheim, 1996, pp. 148 ± 159; c) M. Beller, B. Cornils, C. D. Froh-
ning, C. W. Kohlpaintner, J. Mol. Catal. 1995, 104, 17 ± 85.
Synthesis, Structure, and Reactivity of a
Diphosphadiferratetrahedrane with a
Fe Fe Double Bond**
Christine Eichhorn, Otto J. Scherer,* Thorsten Sögding,
and Gotthelf Wolmershäuser
[4] Review: a) I. P. Beletskaya, Chem. Rev. 2000, 100, 3009 ± 3066; b) V. V.
Grushin, H. Alper, Top. Organomet. Chem. 1999, 3, 193 ± 226; c) T. H.
Riermeier, A. Zapf, M. Beller, Top. Catal. 1997, 4, 301 ± 309.
[5] Selected recent articles on chloroarene activation with regard to Heck
and Suzuki reactions: a) A. Ehrentraut, A. Zapf, M. Beller, Synlett
2000, 1589 ± 1592; b) A. Ehrentraut, A. Zapf, M. Beller, Angew.
Chem. 2000, 112, 4315 ± 4317; Angew. Chem. Int. Ed. 2000, 39, 4153 ±
Dedicated to Professor Marianne Baudler
on the occasion of her 80th birthday
Whereas in the chemistry of acetylene complexes of iron,
compound 1 containing a C2Fe2 tetrahedrane framework and
a Fe Fe double bond was prepared and crystallographically
characterized already in 1976,[1] for the iso(valence)electronic
Â
4155; c) M. Gomez Andreu, A. Zapf, M. Beller, Chem. Commun.
2000, 2475 ± 2476; d) A. Zapf, M. Beller, Chem. Eur. J. 2000, 6, 1830 ±
1833; e) V. P. W. Böhm, C. W. K. Gstöttmayr, T. Weskamp, W. A.
Herrmann, J. Organomet. Chem. 2000, 595, 186 ± 190; f) C. Zhang,
M. L. Trudell, S. P. Nolan, Tetrahedron Lett. 2000, 41, 595 ± 598;
g) A. F. Littke, G. C. Fu, J. Org. Chem. 1999, 64, 10 ± 11; h) K. H.
Shaughnessy, P. Kim, J. F. Hartwig, J. Am. Chem. Soc. 1999, 121,
2123 ± 2132; i) A. F. Littke, G. C. Fu, Angew. Chem. 1998, 110, 3586 ±
3587; Angew. Chem. Int. Ed. 1998, 37, 3387 ± 3388; j) J. P. Wolfe, R. A.
Singer, B. H. Yang, S. L. Buchwald, J. Am. Chem. Soc. 1999, 121,
9550 ± 9561; k) J. P. Wolfe, S. L. Buchwald, Angew. Chem. 1999, 111,
2570 ± 2573; Angew. Chem. Int. Ed. 1999, 38, 2413 ± 2416; l) X. Bei, T.
Crevier, A. S. Guram, B. Jandeleit, T. S. Powers, H. W. Turner, T. Uno,
W. H. Weinberg, Tetrahedron Lett. 1999, 40, 3855 ± 3858; m) M. Beller,
A. Zapf, Synlett 1998, 792 ± 794.
:
:
ꢁ
ꢁ
and isolobal (HC ! P, HC CH ^ P P ) diphosphadiferra-
ꢀ
tetrahedranes only the complex 2 with a Fe Fe single bond
and additional P-coordination is known.[2]
Diphosphadimetallatetrahedranes of the type [{LnM}2-
(m-h2:h2-P2)] (LnM 15 valence-electron(VE) fragment)[3]
synthesized to date all display M M single bonds, and with
six skeleton electron pairs (SEPs) for the tetrahedral M2P2
framework are considered as nido clusters. According to
theoretical investigations a decrease (5 SEPs) as well as an
increase (7 SEPs) in the number of electrons in the skeleton
lead to changes of the M2P2 framework.[4]
[6] a) T. A. Stromnova, I. I. Moiseev, Russ. Chem. Rev. 1998, 67, 485 ± 514;
b) K. Kudo, M. Hidai, Y. Uchida, J. Organomet. Chem. 1971, 33, 393 ±
398; c) M. Hidai, M. Kokura, Y. Uchida, J. Organomet. Chem. 1973,
52, 431 ± 435.
[7] a) Y. Ben-David, M. Portnoy, D. Milstein, J. Am. Chem. Soc. 1989, 111,
8742 ± 8744; b) Y. Ben-David, M. Portnoy, D. Milstein, J. Chem. Soc.
Chem. Commun. 1989, 1816 ± 1817; c) M. Portnoy, D. Milstein,
Organometallics 1993, 12, 1655 ± 1664.
[8] a) M. Huser, M.-T. Youinou, J. A. Osborn, Angew. Chem. 1989, 101,
1427 ± 1430; Angew. Chem. Int. Ed. Engl. 1989, 28, 1386 ± 1389;
b) V. V. Grushin, H. Alper, J. Chem. Soc. Chem. Commun. 1992, 611 ±
612; c) T. Miyawaki, K. Nomura, M. Hazama, G. Suzukamo, J. Mol.
[*] Prof. Dr. O. J. Scherer, Dipl.-Chem. C. Eichhorn,
Dipl.-Chem. T. Sögding, Dr. G. Wolmershäuser[]
Fachbereich Chemie der Universität
Erwin-Schrödinger-Strasse, 67663 Kaiserslautern (Germany)
Fax : (49)631-205-4676
[ ] Crystal structure analysis.
[**] This work was supported by the Fonds der Chemischen Industrie and
by the Graduiertenkolleg ¹Phosphorchemie als Bindeglied verschie-
dener chemischer Disziplinenª.
Angew. Chem. Int. Ed. 2001, 40, No. 15
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