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Y.-H. Cheng et al. / Tetrahedron 63 (2007) 12277–12285
yields of 7a and 7b are 95% (0.201 g, 0.19 mmol) and 53.5%
(0.104 g, 0.11 mmol), respectively. Both crystals of 7a and
7b were grown from a hexanes/CH2Cl2¼1:1 mixed solvent
in 4 ꢁC environment.
CCDC no. 653963, 653964, and 653965 for compounds 7a,
7b, and 8a, respectively. Copies of this information may be
obtained free of charge from the Director, CCDC, 12 Union
Road, Cambridge CB2 1EZ, UK (Fax: +44 1223 336033;
cam.ac.uk). Supplementary data associated with this article
Compound 7a: 1H NMR (CDCl3, d/ppm): 2.29 (s, 3H), 3.79
(s, 6H), 6.37 (s, 2H), 7.40–7.49 (m, 6H), 7.84–7.89 (m, 4H);
31P NMR (CDCl3, d/ppm): 107.2 ppm; MS (FAB):
m/z¼1021 [M+ꢀCl].
Compound 7b: 1H NMR (CDCl3, d/ppm): 1.52 (d, 18H, JP–H
¼
References and notes
16.0 Hz), 2.27 (s, 3H), 3.98 (s, 6H), 6.35 (s, 2H); 31P NMR
(CDCl3, d/ppm): 167.1 ppm; MS (FAB): m/z¼942 [M+ꢀCl].
1. General reviews, see: (a) Alberico, D.; Scott, M. E.; Lautens,
M. Chem. Rev. 2007, 107, 174; (b) Corbet, J.-P.; Mignani, G.
Chem. Rev. 2006, 106, 2651; (c) Cross-Coupling Reactions:
A Practical Guide in Topics in Current Chemistry; Houk,
K. N., Sessler, H., Lehn, J.-M., Ley, S. V., de Meijere, A.,
4.5. Synthesis of 8a
The two reactants, 5a (0.40 mmol, 0.114 g) and
Pd(COD)Cl2 (0.20 mmol, 0.057 g) with 10 ml CH2Cl2
were placed in a 100 ml round-bottomed flask charged
with magnetic stirrer. The solution was stirred at 40 ꢁC for
8 h before the solvent was removed in reduced pressure.
The residue was washed with 10 ml hexanes first and dried
again. An yellow colored solid was obtained and was identi-
fied as 8a. The yield of 8a is 94% (0.166 g, 0.188 mmol).
Suitable crystals of 8a for X-ray determination were ob-
tained from a hexanes/CH2Cl2¼1:1 mixed solvent in 4 ꢁC
environment.
€
Schreiber, S. L., Thiem, J., Trost, B. M., Vogtle, F.,
Yamamoto, H., Eds.; Springer: Heidelberg, 2002; Vol. 219;
(d) Hegedus, L. S. Organometallics in Organic Synthesis;
Schlosser, M., Ed.; Wiley: New York, NY, 1994; p 383; (e)
Palladium Reagents and Catalysts: Innovations in Organic
Synthesis; Fuji, J., Ed.; Wiley: Chichester, UK, 1995; (f)
Geissler, H. Transition Metals for Organic Synthesis; Beller,
M., Bolm, C., Eds.; Wiley-VCH: Weinheim, 1998; Vol. 1,
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Diederich, F., Stang, P. J., Eds.; Wiley-VCH: Weinheim,
Germany, 1998; (h) Palladium in Heterocyclic Chemistry: A
Guide for the Synthetic Chemist; Li, J. J., Gribble, G. W.,
Eds.; Pergamon: Amsterdam, 2000.
Compound 8a: 1H NMR (CDCl3, d/ppm): 2.07 (s, 3H), 3.26
(s, 6H), 5.89 (s, 2H), 7.16–7.30 (m, 6H), 7.89–7.91 (m, 4H);
31P NMR (CDCl3, d/ppm): 118.9 ppm; MS (FAB): m/z¼846
[M+ꢀCl].
2. (a) Suzuki, A. Metal-Catalyzed Cross-coupling Reactions;
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4.6. X-ray crystallographic studies
Suitable crystals of 7a, 7b, and 8a were sealed in thin-walled
glass capillaries under nitrogen atmosphere and mounted on
a Bruker AXS SMART 1000 diffractometer. Intensity data
were collected in 1350 frames with increasing u (width of
0.3ꢁ per frame). The absorption correction was based on
the symmetry equivalent reflections using SADABS pro-
gram. The space group determination was based on a check
of the Laue symmetry and systematic absences, and was
confirmed using the structure solution. The structure was
solved by direct methods using a SHELXTL package.13
All non-H atoms were located from successive Fourier
maps and hydrogen atoms were refined using a riding model.
Anisotropic thermal parameters were used for all non-H
atoms, and fixed isotropic parameters were used for H
atoms.14 Crystallographic data for compounds 7a, 7b, and
8a are summarized in Table 1.
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Acknowledgements
We thank the National Science Council of the R.O.C. (Grant
NSC 95-2113-M-005-015-MY3) for financial support.
Supplementary data
Crystallographic data for the structural analysis have been
deposited with the Cambridge Crystallographic Data Center,