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[6] a) F. A. Ajulu, P. B. Hitchcock, F. Mathey, R. A. Michelin, J. F. Nixon,
A. J. L. Pombeiro, J. Chem. Soc. Chem. Commun. 1993, 142; b) F. A.
Ajulu, D. Carmichael, P. B. Hitchcock, F. Mathey, M. F. Meidine, J. F.
Nixon, L. Ricard, M. L. Riley, J. Chem. Soc. Chem. Commun. 1992, 750;
c) S. S. Al Juaid, D. Carmichael, P. B. Hitchcock, A. Marinetti, F.
Mathey, J. F. Nixon, J. Chem. Soc. Dalton Trans. 1991, 905.
[7] a) D. Männig, H. Nöth, Angew. Chem. 1985, 97, 854; Angew. Chem. Int.
Ed. Engl. 1985, 24, 878; b) Review: K. Burgess, M. J. Ohlmeyer, Chem.
Rev. 1991, 91, 1179; c) J. M. Brown, G. C. Lloyd-Jones, J. Am. Chem.
Soc. 1994, 116, 866, and references therein.
[8] In the presence of the olefin alone, no reaction is observed, while
addition of borane alone caused a slight color change and 31P NMR
signals appeared in the region of the intact BABAR-Phos ligand.
However, we have been unable to isolate any pure product yet.
[9] The alcohols 13a, b and 14a, b can be obtained by passing a stream of
oxygen (or air) through the reaction mixtures. Unfortunately, although
the complexes were stable under O2 they decomposed in the presence
of the organoboranes 11a, b, 12a, b. However, the ligands 1a, b could
be recovered. Workup with alkaline H2O2 destroys the phosphiranes as
well. Probably these decomposition reactions are caused by radicals
being formed from organoboranes and O2 (see: H. J. Brown, M. M.
Midland, Tetrahedron 1987, 43, 4059) or by the high oxidizing power of
alkaline H2O2. However, one could circumvent catalyst destruction by
separation before workup.
markable resistance to oxgen should stimulate investigations
into methods to recycle BABAR-Phos complexes (e.g. by
immobilization or making them water soluble).[9]
Experimental Section
3: Compound 1a (477 mg, 1.7 mmol) was added to
a solution of
À
[Rh(cod)2] O3SCF3 (200 mg, 0.42 mmol) in THF (3 mL). The product
precipitated as a light yellow microcrystalline powder which was washed
with Et2O (2 Â 1 mL) and dried in vacuum (yield 472mg, 82%). Crystals
suitable for an X-ray analysis were grown from a CH2Cl2 solution layered
with n-hexane. Elemental analysis (%) calcd for C73H72F3N4O3P4RhS: C
64.03, H 5.30, N 4.09; found: C 64.12, H 5.27, N 4.18.
5: Compound 4 (200 mg, 0.41 mmol) and 1b (365 mg, 0.82mmol) were
combined in MeCN (3 mL). After about 1 h without stirring, the product
precipitated in the form of deep brown-red crystals, which were collected
by filtration and washed with MeCN (2 Â 1 mL). After drying under
vacuum 5 was obtained in 91% yield (458 mg). Elemental analysis (%)
calcd for C96H62Cl4F24N6P4Rh4: C 47.39, H 2.57, Cl 5.83, P 5.09, N 3.45;
found: C 47.39, H 2.83, Cl 5.95, P 5.10, N 3.60.
7a, b: A suspension of 5 (200 mg, 0.08 mmol) in MeCN (2 mL) was treated
with AgPF6 (38 mg, 0.15 mmol) or AgSO3CF3 (40 mg, 0.15 mmol),
respectively. After filtration from precipitated AgCl, the solution was
reduced to about about a tenth of its volume. At À258C, the products
crystallized as brown-red rhombs; yields: 7a: 171 mg (79%); 7b: 178 mg
(76%). Elemental analysis (%) calcd for C104H74Cl2F36N10P6Rh4 (7a): C
44.36, H 2.65, N 4.97; found: C 44.31, H 2.59, N 5.01.
Received: December 22, 1999
Revised: February 28, 2000 [Z14445]
[1] a) J. Liedtke, S. Loss, G. Alcaraz, V. Gramlich, H. Grützmacher, Angew.
Chem. 1999, 110, 1724; Angew. Chem. Int. Ed. 1999, 38, 1623; b) J.
Liedtke, S. Loss, H. Grützmacher, Tetrahedron 2000, 56, 143.
[2] a) C. Widauer, H. Grützmacher, T. Ziegler, Organometallics 2000, 24,
2097; b) D. G. Musaev, A. M. Mebel, K. Morokuma, J. Am. Chem. Soc.
1994, 116, 10693; c) A. E. Dorigo, P. von R. Schleyer, Angew. Chem.
1995, 107, 108; Angew. Chem. Int. Ed. Engl. 1995, 34, 115.
Halogen ± Magnesium Exchange via
Trialkylmagnesates for the Preparation of Aryl-
and Alkenylmagnesium Reagents**
Kazuya Kitagawa, Atsushi Inoue, Hiroshi Shinokubo,
and Koichiro Oshima*
[3] a) Irreversible metal insertion reactions into (R2C)2X rings (X CR2;
NR, O): D. Carmichael, P. B. Hitchcock, J. F. Nixon, F. Mathey, L.
Ricard, J. Chem. Soc. Dalton Trans. 1993, 1811; b) formation of epoxide
by thermolysis of a 1-nickela-2-oxacyclobutane: A. Miyashita, J. Ishida,
H. Nohira, Tetrahedron Lett. 1986, 27, 2 12 7.
The utility of organometallic ate complexes such as R2CuLi,
R3ZnLi, and R4AlLi in organic synthesis is well known, and
numerous studies have been devoted to the development of
new methods which make use of these reagents. Several
synthetic methods which utilize R3MnLi have also been
reported recently.[1] These organometallic ate complexes are
known to induce halogen ± metal exchange reactions in some
cases.[2]
Recently, Knochel et al. have shown that polyfunctional
arylmagnesium and alkenylmagnesium reagents can be pre-
pared by an iodine ± magnesium exchange reaction using
RMgX.[3, 4] It then occurred to us that a magnesium-ate
complex (R3MgLi)[5] would be more effective than an
alkylmagnesium halide (RMgX) for the halogen ± magnesi-
um exchange reaction. Indeed, we have found that treatment
[4] Crystal structure analyses: 3: tetragonal, space group P4nc; a
16.5970(5), c 11.7946(3) ; V 3248.9(2) 3; Z 2 , Mo radiation,
Ka
2Vmax 52.728; 21747 reflections, 3324 independent (Rint 0.0728);
R1 0.05, wR2 0.1232 (based on F 2) for 199 parameters and 2746
reflections with I > 2s(I). 7b: monoclinic, space group P21/n; a
17.98168(5), b 18.9535(5), c 18.5737(4) , b 104.093(1)8; V
6139.7(3) 3; Z 2 , MoKa radiation, 2Vmax 52.748; 45154 reflections,
12557 independent (Rint. 0.0791); R1 0.0494, wR2 0.0931 (based on
F 2) for 772parameters and 8021 reflections with
I > 2s(I). Both
structures were solved by using direct methods and were refined against
full matrix (versus F 2) with SHELXTL (Version 5.0). Non-hydrogen
atoms were treated anisotropically, hydrogen atoms were refined on
calculated positions using the riding model. The triflate anion in 3 was
refined as a rigid group disordered over four equivalent positions with
isotropic temperature factors. Noncoordinating acetonitrile molecules
in 7b were refined with isotropic temperature factors, one of the
molecules was disordered over two equivalent positions with an
occupancy factor of 0.4. Crystallographic data (excluding structure
factors) for the structures reported in this paper have been deposited
with the Cambridge Crystallographic Data Centre as supplementary
publication no. CCDC-137943 (3) and CCDC-137942( 7b). Copies of
the data can be obtained free of charge on application to CCDC, 12
Union Road, Cambridge CB21EZ, UK (fax: (44)1223-336-033;
e-mail: deposit@ccdc.cam.ac.uk).
[*] Prof. Dr. K. Oshima, K. Kitagawa, A. Inoue, Dr. H. Shinokubo
Department of Material Chemistry
Graduate School of Engineering, Kyoto University
Kyoto 606 ± 8501 (Japan)
Fax : (81)75-753-4863
[**] This work was supported by a Grant-in-Aid for Scientific Research
from the Ministry of Education, Science, Sports, and Culture, Japan.
[5] A. Marinetti, F. Mathey, L. Ricard, Organometallics 1993, 12, 1207.
Angew. Chem. Int. Ed. 2000, 39, No. 14
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