Efficient Suzuki-type cross-coupling of enantiomerically pure cyclopropylboronic acids

Full text of DOI:10.1002/(SICI)1521-3773(19981102)37:20<2845::AID-ANIE2845>3.0.CO;2-U

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waiting time (10 to 30 minutes) allowed the system to reach equilibrium.
Steps of 2 mNm 1 were usually chosen. The subphase was water (Q grade,
Millipore) with a resistivity higher than 18 MWcm. The dipping speed was
generally set to 0.5 cmmin 1. Films were transferred onto optically polished
calcium fluoride (precoated with three monolayers of behenic acid) for IR
measurements, onto optically polished and silanized glass substrate for low-
angle X-ray experiments, and onto a diamagnetic mylar sheet for magnetic
SQUID measurements.
[12] C. T. Seip, G. E. Granroth, M. W. Meisel, D. R. Talham, J. Am. Chem.
Soc. 1997, 119, 7084 ± 7094.
[13] J. Reiche, U. Pietsch, H.-P. Fink, H. Lemmetuinen, Acta Polymer.
1992, 43, 206.
[14] K. Takeda, K. Awaga, Phys. Rev. B 1997, 56, 14560 ± 14565.
[15] M. Vandevyver, A. Barraud, A. Ruaudel-Teixier, P. Maillard, C.
Gianotti, J. Colloid Interface Sci. 1982, 85, 571.
IR spectra were recorded on
a FTIR 750 Nicolet spectrometer. To
determine the orientation of the lipid molecules in the LB films, the linear
dichroism in the IR region was used. In a first spectrum, the incident light
was set perpendicular to the substrate normal; in a second, the incident IR
beam formed an angle of 608 with the substrate normal. The out-of-plane
dichroic ratio b for each band is then defined as the ratio of the IR
absorption in both spectra. The angle between the substrate normal and the
transition dipole moment can then be evaluated from b using a model
already described.[15]
Efficient Suzuki-Type Cross-Coupling of
Enantiomerically Pure Cyclopropylboronic
Acids**
X-ray diffraction patterns were obtained using a conventional generator
(Kristalloflex Siemens Ltd) delivering non-monochromatized line-focused
CuKa radiation. This beam passes through the sample, which is mounted
vertically and oscillated during exposure. The integrated intensities of the
Bragg reflections were collected by an INEL CPS 120 curved position-
sensitive detector (with a resolution of 0.18 in 2q) associated with an IBM
computer for peak assignments.
Shao-Man Zhou, Min-Zhi Deng,* Li-Jun Xia, and
Ming-Hua Tang
Transition metal catalyzed Suzuki-type cross-coupling re-
actions are versatile and powerful methods for the formation
of carbon ± carbon bonds, because most of these reactions are
stereospecific and offer many other advantages.[1] The pro-
posed mechanism of the palladium-catalyzed cross-cou-
pling[1a] contains a transmetalation reaction between organo-
boron compounds and palladium halide complexes as well as
subsequent reductive elimination steps. Undoubtedly, under-
standing the change in stereochemistry of the chiral carbon
atom upon use of a chiral alkylboron compound as reagent is
of interest for organic chemists. Bäckvall and Škermark
reported that the configuration of the chiral carbon atom of
the alkyl group was retained upon transmetalation from
mercury to palladium.[2] Stille found that the transmetalation
reaction of a chiral benzyltin compound with a palladium
complex in hexamethyl phosporamide (HMPA) proceeded
with inversion.[3] Hiyama and co-workers investigated the
palladium-catalyzed cross-coupling reaction of chiral alkylsi-
lanes with aryl triflates (triflate ˆ trifluoromethanesulfonate).
They determined that the stereochemistry is affected by both
the reaction temperature and the nature of the solvent and
could be controlled from almost complete retention to
inversion by tuning these factors.[4] Recently, we prepared
racemic cyclopropylboronic acids and subjected them to
Suzuki-type coupling reactions with bromoarenes[5] or bro-
moacrylates.[6] Herein we report the palladium-catalyzed
cross-coupling of optically active cyclopropylboron com-
pounds.
The magnetic measurements were performed with a Quantum Design
MPMS-XL SQUID magnetometer between 2 and 300 K. For such experi-
ments, about 300 layers were deposited on a diamagnetic mylar sheet
(0.075 Â 5 Â 15 mm). The procedure followed for the magnetic suscepti-
bility measurement is described elsewhere.[11] For the magnetization
measurements the hysteresis loops were recorded in about 5 hours. Each
loop contains 180 points. To stabilize each data point a time of about
2 minutes was required. The errors in the magnetization data are in the
range of 1 ± 5%.
Received: May 13, 1998 [Z11851IE]
German version: Angew. Chem. 1998, 110, 3053 ± 3056
Keywords: clusters ´ magnetic properties ´ monolayers ´
single-molecule magnets ´ thin films
[1] a) D. Gatteschi, A. Caneschi, L. Pardi, R. Sessoli, Science 1994, 265,
1054 ± 1058; b) R. Sessoli, D. Gatteschi, A. Caneschi, M. A. Novak,
Nature 1993, 365, 141 ± 143.
[2] a) D. N. Hendrickson, D. M. Adams, C.-C. Wu, S. M. J. Aubin in
Magnetism: A supramolecular function (Ed.: O. Kahn), NATO ASI
Ser. Ser. C 484 1996, pp. 357 ± 382; b) see G. Christou in ref. [2a]
pp. 383 ± 409; c) S. M. J. Aubin, M. W. Wemple, D. M. Adams, H. L.
Tsai, G. Christou, D. N. Hendrickson, J. Am. Chem. Soc. 1996, 118,
7746 ± 7754; d) Z. Sun, C. M. Grant, S. L. Castro, D. N. Hendrickson,
G. Christou, Chem. Commun. 1998, 721.
[3] M. R. Cheesman, V. S. Oganesyan, R. Sessoli, D. Gatteschi, A. J.
Thomson, Chem. Commun. 1997, 1677 ± 1678.
[4] H. J. Eppley, H. L. Tsai, N. de Vries, K. Folting, G. Christou, D. N.
Hendrickson, J. Am. Chem. Soc. 1995, 117, 301 ± 317.
[5] R. Sessoli, H. L. Tsai, A. R. Schake, S. Wang, J. B. Vincent, K. Folting,
D. Gatteschi, G. Christou, D. N. Hendrickson, J. Am. Chem. Soc. 1993,
115, 1804 ± 1816.
[6] S. M. J. Aubin, Z. Sun, I. A. Guzei, A. L. Rheingold, G. Christou, D. N.
Hendrickson, Chem. Commun. 1997, 2239 ± 2240.
[7] J. Friedman, M. P. Sarachik, J. Tejada, R. Ziolo, Phys. Rev. Lett. 1996,
76, 3830 ± 3833.
[8] L. Thomas, F. Lionti, R. Ballou, D. Gatteschi, R. Sessoli, B. Barbara,
Nature 1996, 383, 145 ± 147.
[*] Prof. M.-Z. Deng, Dr. S.-M. Zhou
Laboratory of Organometallic Chemistry
Prof. L.-J. Xia, M.-H. Tang
Analytical Chemistry Department
Shanghai Institute of Organic Chemistry
Chinese Academy of Sciences
354 Fenglin Lu, Shanghai 200032 (China)
Fax : (‡ 86)21-64166128
E-mail: dengmz@pub.sioc.ac.cn
[9] B. Schwarzschild, Phys. Today 1997, 17 ± 19.
[10] A. Ulman, An Introduction to Ultrathin Organic Films: From
Langmuir-Blodgett to Self-Assembly, Academic Press, Boston, 1991.
[**] We are grateful to the Natural Science Foundation of China for
financial support.
Â
Â
Supporting information for this article is available on the WWW
under http://www.wiley-vch.de/home/angewandte/ or from the
author.
[11] M. Clemente-Leon, C. Mingotaud, B. Agricole, C. Gomez-Garcia, E.
Coronado, P. Delhaes, Angew. Chem. 1997, 109, 1143 ± 1145; Angew.
Chem. Int. Ed. Engl. 1997, 36, 1114 ± 1116.
Angew. Chem. Int. Ed. 1998, 37, No. 20
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In the initial investigation, (E)-styrylboronic acid was
esterified by (‡)-diisopropyl tartrate (DIPT), and subsequent
asymmetric cyclopropanation of the styrylboronic ester gave
2-phenylcyclopropylboronic ester. Afterwards, palladium-
catalyzed cross-coupling with o-bromoanisole was conducted
at 1008C with toluene as solvent to afford optically active
cyclopropyl-substituted anisol (62% ee) in 26% overall yield
(Scheme 1).
Scheme 1. Synthesis of optically active cyclopropyl-substituted anisol by
palladium-catalyzed cross-coupling.
Scheme 2. Synthetic route to optically active cyclopropyl-substituted
benzene derivatives. See Table 1 for the substituent R.
The result was unsatisfactory, in particular the yield of
coupling product was poor. Pietruszka et al. also investigated
the cyclopropanation of alkenylboronic esters derived from
(‡)-DIPTand alkenyl boronic acids and the subsequent cross-
coupling of the cyclopropanation product with iodobenzene;
they obtained similar results.[7] The Suzuki-type cross-cou-
pling of cyclopropylboronic esters with aryl halides was also
reported by Marsden et al.,[8] but the yields of coupling
products were lower. We recently showed that the yields of
coupling products upon use of cyclopropylboronic acids[5, 6] as
starting materials were higher than with cyclopropylboronic
esters.[8] Therefore, we attempted to hydrolyze the cyclo-
propylboronic ester of DIPT with many reagents (BF3 ´ Et2O,
TiCl4, AlCl3, 2n HCl, 2n H2SO4, etc.) to afford the
corresponding cyclopropylboronic acid, but the efforts failed.
Fortunately, in numerous experiments on different derivatives
of tartaric acid, it was found that in the asymmetrically
induced cyclopropanation of (E)-1-alkenylboronic ester[9]
(‡)-N,N,N'N'-tetramethyltartaric acid diamide (TMTA)[10] is
a better chiral auxiliary than (‡)-DIPT. The optically active
cyclopropylboronic ester of (‡)-TMTA obtained in situ was
readily hydrolyzed by water to give the corresponding
optically active cyclopropylboronic acid in good yield
(Scheme 2).
Under our previous conditions[5, 6] the optically active
cyclopropylboronic acid could easily enter the cross-coupling
reaction with bromobenzene to afford the optically active
cyclopropyl-substituted benzene (Scheme 2). The absolute
configuration of the product was determined by comparison
of the specific rotation. For example, the (E)-styrylboronic
ester of (‡)-TMTA (1) was cyclopropanated to give, after
hydrolysis, (1R,2R)-2-phenylcyclopropylboronic acid (3). This
species underwent oxidation to (1R,2S)-( )-2-phenyl-1-cyclo-
propanol (5), for which the sign of the specific rotation agreed
with that reported[11] (Scheme 2). The sense of the specific
rotation of product 4a obtained by coupling of 3 with
bromobenzene was also the same as that of (1R,2R)-( )-1,2-
diphenylcyclopropane[12] (Table 1), and the ee value of the
oxidation product 5 was similar to that of 4a (Scheme 2). In
addition, the reactions of cyclopropylboronic acid of the same
optical purity with different electrophiles gave the corre-
sponding cross-coupling products with similar optical purities
(Table 1). These results suggest that the absolute configura-
tion of the center of chirality, on which the coupling reaction
occurred, was retained in the coupling process.
Of course also S,S isomers (4b, 4d, 4e, 4 f, 4i, 4k, 4m) could
be obtained by using ( )-TMTA as auxiliary. The results of
the coupling reaction between optically active cyclopropyl-
boronic acids and various electrophiles are shown in Table 1.
The enantiomeric excesses of all products were determined by
HPLC on appropriate chiral columns. Table 1 demonstrates
that the chemical yields and optical purities of the coupling
products thus obtained were higher than with previously
reported methods.
We have presented the first detailed investigations of
palladium-catalyzed Suzuki-type cross-coupling reactions
with chiral organoboron coumpounds. The results indicate
that the absolute configuration of the chiral carbon atom was
retained in the cross-coupling process. The optical purities and
yields of the coupling products are satisfactory. This method
opens the door for the synthesis of other optical active
cyclopropyl derivatives by the preparation and subsequent
cross-coupling of optically active cyclopropylboronic acids
with electrophiles.
Received: May 11, 1998 [Z11839IE]
German version: Angew. Chem. 1998, 110, 3061 ± 3063
Keywords: boron
´ chiral auxiliaries ´ cross-coupling ´
palladium
[1] a) N. Miyaura, A. Suzuki, Chem. Rev. 1995, 95, 2457 ± 2483; b) T.
Ishiyama, M. Yamamoto, N. Miyaura, Chem. Lett. 1996, 12, 1117; c) T.
Ishiyama, T. Ahiko, N. Miyaura, Tetrahedron Lett. 1996, 37, 6889; d) S.-
B. Jang, Tetrahedron Lett. 1997, 38, 1793; e) W. Shen, Tetrahedron Lett.
1997, 38, 5575; f) M. Larhed, A. Hallberg, J. Org. Chem. 1996, 61, 9582.
[2] J. E. Bäckvall, B. J. Škermark, J. Chem. Soc. Chem. Commun. 1975,
82.
[3] a) J. W. Labadie, J. K. Stille, J. Am. Chem. Soc. 1983, 105, 669; b) J. W.
Labadie, J. K. Stille, J. Am. Chem. Soc. 1983, 105, 6129.
[4] Y. Hatanaka, T. Hiyama, J. Am. Chem. Soc. 1990, 112, 7793.
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Table 1. Coupling reactions of various chiral cyclopropylboronic acids with electrophiles.[a]
Chiral
auxiliary
Product
[a]TD [8]
(c in CHCl3)
Config.
Yield
[%][b]
ee
[%]
(‡)-TMTA
4a
4b
[a]1D7
(1R,2R)
77
91[d]
91[d]
379.0 (0.496)[c]
(
)-TMTA
[a]1D6
388.2 (1.003)[c]
(1S,2S)
(1R,2R)
(1S,2S)
81
(‡)-TMTA
4c
4d
[a]1D6
425.3 (1.123)
90
88
91[d]
90[d]
(
(
(
)-TMTA
)-TMTA
)-TMTA
[a]1D6
421.8 (1.103)
4e
4 f
4g
[a]1D6
250.8 (1.250)
(1S,2S)
(1S,2S)
(1R,2R)
78
73
83
91[d]
90[e]
91[f]
[a]1D6
343.6 (1.164)
(‡)-TMTA
(‡)-TMTA
[a]1D6
159.5 (0.981)
4h
4i
[a]1D6
450 (0.322)
(1R,2R)
(1S,2S)-
(1R,2R)
(1S,2S)
(1R,2R)
79
84
87
86
80
92[d]
90[d]
89[d]
89[d]
92[d]
(
)-TMTA
[a]1D2
426.8 (0.963)
(‡)-TMTA
4j
4k
4l
[a]1D6
519.0 (0.973)
(
)-TMTA
[a1D2
511.0 (1.000)
(‡)-TMTA
[a]1D6
377.3 (0.275)
(
)-TMTA
4m
4n
[a]1D7
358.1 (0.296)
(1S,2S)
81
76
90[d]
82[d]
(‡)-TMTA
[a]2D0
40.1 (0.412)
(1R,2R)
[a] Coupling reactions were conducted at 1008C in toluene with the chiral cyclopropylboronic acids (1.1 equiv), the bromoarenes or bromo-
acrylates (1.0 equiv), K3PO4 ´ 3H2O (3.3 equiv), and [Pd(PPh3)4] (0.03 equiv). [b] Yields of isolated product based on the bromoarene or bromo-
acrylate. [c] (1R,2R)-1,2-Diphenylcyclopropane (4a): [a]D20
ˆ
4188 (c ˆ 0.96 in CHCl3),[12b] 100% ee; (1S,2S)-1,2-diphenylcyclopropane (4b): [a]D22 ˆ 3628
(c ˆ 0.038 in CHCl3),[12a] 86% ee. [d] Determined by HPLC (Chiralcel OD). [e] Determined by HPLC (Chiralcel OJ). [f] Determined by HPLC
(Chiralcel AD).
[5] X.-Z. Wang, M.-Z. Deng, J. Chem. Soc. Perkin Trans 1 1996, 2663 ±
2664.
[11] T. Imai, H. Maineta, S. Nishida, J. Org. Chem. 1990, 55, 4986.
[12] a) M. Mintas, A. Mannschreck, J. Chem. Soc. Chem. Commun.
1979,602; b) M. P. Wachter, T. M. Harris, Tetrahedron 1970, 26, 1685.
[6] S.-M. Zhou, Y.-L. Yan, M.-Z. Deng, Synlett 1998, 198 ± 200.
[7] J. Pietruszka, M. Widenmeyer, Synlett 1997, 977 ± 979.
[8] J. P.Hildebrand, S. P. Marsden, Synlett 1996, 893 ± 894.
[9] a) P. Fontani, B. Carboni, M. Vaultier, R. Carrie, Tetrahedron Lett.
1989, 30, 4814; b) P. Fontani, B. Carboni, M. Vaultier, G. Maas,
Synthesis. 1991, 605.
[10] Both enantiomers of the tartramide can easily be prepared by
Seebachꢁs procedure: D. Seebach, H.-O. Kalinowski, W. Langer, G.
Crass, E.-M. Wilka, Organic Syntheses, Collect. Vol. VII, Wiley, New
York, 1990, pp. 41 ± 50.
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