R1 bearing benzyl or phenyl groups, a lower reactivity and
moderate enantioselectivity were obtained (Table 3, entries 13–14).
To determine the absolute configuration, chiral amine 9j
was acylated with benzoyl chloride and then recrystallized
from DCM/hexane to give amide 10 (4 99% ee) as a colorless
crystal, and its configuration was assigned as (S)-10 by X-ray
diffraction analysis (see ESIw).12 The other products’ absolute
configurations were assigned by analogy with 9j.
Chem.–Eur. J., 2006, 12, 2318; (g) S.-F. Zhu, J.-B. Xie,
Y.-Z. Zhang, S. Li and Q.-L. Zhou, J. Am. Chem. Soc., 2006,
128, 12886; (h) T. Imamoto, N. Iwadate and K. Yoshida, Org.
Lett., 2006, 8, 2289; (i) M. N. Cheemala and P. Knochel, Org.
Lett., 2007, 9, 3089; (j) M. T. Reetz and O. Bondarev, Angew.
Chem., Int. Ed., 2007, 46, 4523; (k) C. Li, C. Wang, B.
Villa-Marcos and J. Xiao, J. Am. Chem. Soc., 2008, 130, 14450;
(l) Z. Han, Z. Wang, X. Zhang and K. Ding, Angew. Chem., Int.
Ed., 2009, 48, 5345; (m) N. Mrsic, A. J. Minnaard, B. L. Feringa
and J. G. de Vries, J. Am. Chem. Soc., 2009, 131, 8358;
(n) K. Kutlescha, T. Irrgang and R. Kempe, Adv. Synth. Catal.,
2010, 352, 3126.
In summary, we have synthesized
a novel type of
cyclic imine using o-fluoro nitrobenzene derivatives as the
starting materials, which were hydrogenated by using the
Ir/(S)-Xyl-C3*-TunePhos catalyst system in the presence of
morpholine-HCl with up to 94% ee. This method provides
an efficient route to optically active 11-substituted-10,11-
dihydrodibenzo[b,f][1,4]oxazepines.
8 (a) M. Chang, W. Li, G. Hou and X. Zhang, Adv. Synth. Catal.,
2010, 352, 3121; (b) M. Rueping, E. Merino and R. M. Koenigs,
Adv. Synth. Catal., 2010, 352, 2629.
9 (a) W.-B. Wang, S.-M. Lu, P.-Y. Yang, X.-W. Han and
Y.-G. Zhou, J. Am. Chem. Soc., 2003, 125, 10536; (b) S.-M. Lu,
X.-W. Han and Y.-G. Zhou, Adv. Synth. Catal., 2004, 346, 909;
(c) S.-M. Lu, Y.-Q. Wang, X.-W. Han and Y.-G. Zhou, Angew.
Chem., Int. Ed., 2006, 45, 2260; (d) D.-W. Wang, W. Zeng and
Y.-G. Zhou, Tetrahedron: Asymmetry, 2007, 18, 1103;
(e) S.-M. Lu, X.-W. Han and Y.-G. Zhou, J. Organomet. Chem.,
2007, 692, 3065; (f) Y.-G. Zhou, Acc. Chem. Res., 2007, 40, 1357;
(g) X.-B. Wang and Y.-G. Zhou, J. Org. Chem., 2008, 73, 5640;
(h) D.-W. Wang, X.-B. Wang, D.-S. Wang, S.-M. Lu, Y.-G. Zhou
and Y.-X. Li, J. Org. Chem., 2009, 74, 2780; (i) D.-W. Wang,
D.-S. Wang, Q.-A. Chen and Y.-G. Zhou, Chem.–Eur. J., 2010, 16,
1133; (j) D.-S. Wang, J. Zhou, D.-W. Wang, Y.-L. Guo and
Y.-G. Zhou, Tetrahedron Lett., 2010, 51, 525; (k) F.-R. Gou,
W. Li, X. Zhang and Y.-M. Liang, Adv. Synth. Catal., 2010,
352, 2441; (l) Y.-G. Zhou, P.-Y. Yang and X.-W. Han, J. Org.
Chem., 2005, 70, 1679; (m) D.-S. Wang, Q.-A. Chen, W. Li,
C.-B. Yu, Y.-G. Zhou and X. Zhang, J. Am. Chem. Soc.,
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M.-W. Chen, C.-B. Yu, Y. Duan and G.-F. Jiang, Chem. Sci.,
2011, 2, 803.
This work was financially supported by the National
Natural Science Foundation of China (21032003 & 20872140),
and the National Basic Research Program of China
(2010CB833300).
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12 Selected bond lengths [A] and angles [1]: N1–C7, 1.458(5); C6–C7,
1.518(5); C7–C8, 1.537(6); N1–C9, 1.369(5); C9–N1–C7, 118.4(3);
N1–C7–C6, 114.4(3); N1–C7–C8, 110.9(3); C6–C7–C8, 112.0(3);
N1–C7–H7, 106.3; C6–C7–H7, 106.3, C8–C7–H7, 106.3.
c
This journal is The Royal Society of Chemistry 2011
Chem. Commun., 2011, 47, 7845–7847 7847