979; (h) R. Shintani, Y. Sannohe, T. Tsuji and T. Hayashi, Angew.
Chem., Int. Ed., 2007, 46, 7277; (i) S. Sorgel, N. Tokunaga,
¨
K. Sasaki, K. Okamoto and T. Hayashi, Org. Lett., 2008, 10, 589.
4 Diene 4: G. Berthon-Gelloz and T. Hayashi, J. Org. Chem., 2006,
71, 8957.
5 Diene 5: (a) Y. Otomaru, N. Tokunaga, R. Shintani and T. Hayashi,
Org. Lett., 2005, 7, 307; (b) Y. Otomaru, A. Kina, R. Shintani and
T. Hayashi, Tetrahedron: Asymmetry, 2005, 16, 1673.
6 Diene 6: (a) Z.-Q. Wang, C.-G. Feng, M.-H. Xu and G.-Q. Lin,
J. Am. Chem. Soc., 2007, 129, 5336; (b) S. Helbig, S. Sauer,
N. Cramer, S. Laschat, A. Baro and W. Frey, Adv. Synth. Catal.,
2007, 349, 2331.
7 Other chiral diene ligands used for asymmetric reactions:
(a) T. Hayashi, K. Ueyama, N. Tokunaga and K. Yoshida,
J. Am. Chem. Soc., 2003, 125, 11508; (b) C. Fischer, C. Defieber,
T. Suzuki and E. M. Carreira, J. Am. Chem. Soc., 2004, 126,
1628; (c) C. Defieber, J.-F. Paquin, S. Serna and E. M. Carreira,
Fig.
2
ORTEP illustration of Rh(acac)((R)–1a) with thermal
ellipsoids drawn at 50% probability level. Hydrogen atoms and the
disorder are not shown (See ESIz). Selected bond lengths: Rh–Ca =
2.11 A, Rh–Cb = 2.10 A, Rh–Ca0 = 2.13 A, Rh–Cb0 = 2.11 A,
Ca–Cb = 1.41 A, Ca0–Cb0 = 1.39 A.
Org. Lett., 2004, 6, 3873; (d) F. Lang, F. Breher, D. Stein and
¨
¨
H. Grutzmacher, Organometallics, 2005, 24, 2997; (e) J.-F. Paquin,
C. R. J. Stephenson, C. Defieber and E. M. Carreira, Org. Lett.,
2005, 7, 3821; (f) J.-F. Paquin, C. Defieber, C. R. J. Stephenson
and E. M. Carreira, J. Am. Chem. Soc., 2005, 127, 10850;
(g) T. Miura and M. Murakami, Chem. Commun., 2005, 5676;
(h) A. Kina, K. Ueyama and T. Hayashi, Org. Lett., 2005, 7, 5889;
(i) T. Miura, Y. Takahashi and M. Murakami, Chem. Commun.,
2007, 595; (j) T. Nishimura, M. Nagaosa and T. Hayashi, Chem.
Lett., 2008, 37, 860; (k) C.-G. Feng, Z.-Q. Wang, C. Shao,
M.-H. Xu and G.-Q. Lin, Org. Lett., 2008, 10, 4101.
8 (a) A. Kina, H. Iwamura and T. Hayashi, J. Am. Chem. Soc., 2006,
128, 3904; (b) A. Kina, Y. Yasuhara, T. Nishimura, H. Iwamura
and T. Hayashi, Chem.–Asian J., 2006, 1, 707.
9 Steric effects on mono-substituted chiral diene ligands:
T. Gendrineau, O. Chuzel, H. Eijsberg, J.-P. Genet and
S. Darses, Angew. Chem., Int. Ed., 2008, 47, 7669.
10 Review on the electronic effect of chiral ligands: S. P. Flanagan and
P. J. Guiry, J. Organomet. Chem., 2006, 691, 2125.
11 An electron-deficient diene as an efficient ligand for palladium-
catalyzed cross-coupling reactions: Q. Liu, H. Duan, X. Luo,
Y. Tang, G. Li, R. Huang and A. Lei, Adv. Synth. Catal., 2008,
350, 1349.
12 The asymmetric arylation of N-nosylimines is one of the most
challenging rhodium-catalyzed asymmetric additions. For the use
of chiral diene–rhodium catalysts, see ref. 4, 5 and 6a.
13 For the rhodium-catalyzed asymmetric arylation of aromatic imines
with other catalyst systems, see: (a) T. Hayashi and M. Ishigedani,
J. Am. Chem. Soc., 2000, 122, 976; (b) N. Hermanns, S. Dahmen,
bond with an s-trans conformation. As a result, the aryloxy
group becomes located close to the coordination site, cis to the
double bond attached to this ester. The high catalytic activity
of the rhodium complex is believed to arise from the presence
of the double bond conjugated with the ester group. This
electron-deficient double bond is expected to accelerate the
transmetalation forming the rhodium–aryl bond trans to the
ester-substituted double bond.18,19
The absolute configuration of the products, (S) for 9am with
a (R)-1 ligand, is consistent with the stereochemical pathway
that has been proposed for the reactions using C2-symmetric
diene ligands3a,5a (Fig. 3). The present rhodium complex with
ligand 1, which is unsymmetrically substituted with a methyl
and an ester group, will form an aryl–rhodium bond on the
site trans to the more electron-withdrawing double bond,
leaving the remaining site available for coordination of the
imine. The sterically more bulky aryl ester will recognize the
enantioface of the imine more efficiently.9
C. Bolm and S. Brase, Angew. Chem., Int. Ed., 2002, 41, 3692;
¨
(c) M. Kuriyama, T. Soeta, X. Hao, Q. Chen and K. Tomioka,
J. Am. Chem. Soc., 2004, 126, 8128; (d) T. Hayashi, M. Kawai and
N. Tokunaga, Angew. Chem., Int. Ed., 2004, 43, 6125; (e) D. J. Weix,
Y. L. Shi and J. A. Ellman, J. Am. Chem. Soc., 2005, 127, 1092;
(f) H. F. Duan, Y. Jia, L. X. Wang and Q. L. Zhou, Org. Lett., 2006,
8, 2567; (g) R. B. C. Jagt, P. Y. Toullec, D. Geerdink, J. G. de Vries,
B. L. Feringa and A. J. Minnaard, Angew. Chem., Int. Ed., 2006, 45,
2789; (h) K. Kurihara, Y. Yamamoto and N. Miyaura, Adv. Synth.
Catal., 2009, 351, 260.
Fig. 3 Stereochemical pathway with Rh–(R)-1 catalyst.
K. O. thanks the Japan Society for the Promotion of Science
for the award of a fellowship for graduate students.
14 The dependence of enantioselectivity on the ester substituents may
indicate that ester hydrolysis does not take place under the reaction
conditions.
15 For reviews: (a) T. Hayashi and K. Yamasaki, Chem. Rev., 2003,
103, 2829; (b) T. Hayashi, Bull. Chem. Soc. Jpn., 2004, 77, 13;
(c) T. Hayashi, Pure Appl. Chem., 2004, 76, 465; (d) S. Darses and
J.-P. Genet, Eur. J. Org. Chem., 2003, 4313; (e) K. Fagnou and
M. Lautens, Chem. Rev., 2003, 103, 169.
Notes and references
1 For reviews: (a) J. B. Johnson and T. Rovis, Angew. Chem., Int.
Ed., 2008, 47, 840; (b) C. Defieber, H. Grutzmacher and
¨
E. M. Carreira, Angew. Chem., Int. Ed., 2008, 47, 4482.
2 K. Okamoto, T. Hayashi and V. H. Rawal, Org. Lett., 2008, 10, 4387.
3 Dienes 3: (a) N. Tokunaga, Y. Otomaru, K. Okamoto,
K. Ueyama, R. Shintani and T. Hayashi, J. Am. Chem. Soc.,
2004, 126, 13584; (b) Y. Otomaru, K. Okamoto, R. Shintani and
T. Hayashi, J. Org. Chem., 2005, 70, 2503; (c) R. Shintani,
A. Tsurusaki, K. Okamoto and T. Hayashi, Angew. Chem., Int.
Ed., 2005, 44, 3909; (d) R. Shintani, K. Okamoto and T. Hayashi,
Org. Lett., 2005, 7, 4757; (e) T. Hayashi, N. Tokunaga,
K. Okamoto and R. Shintani, Chem. Lett., 2005, 34, 1480;
(f) F.-X. Chen, A. Kina and T. Hayashi, Org. Lett., 2006, 8, 341;
(g) T. Nishimura, Y. Yasuhara and T. Hayashi, Org. Lett., 2006, 8,
16 For the mechanism of rhodium-catalyzed 1,4-addition: T. Hayashi,
M. Takahashi, Y. Takaya and M. Ogasawara, J. Am. Chem. Soc.,
2002, 124, 5052.
17 As an example of a Rh(acac) complex bearing two different olefin
ligands, the X-ray structure of Rh(acac)(CH2QCH2)(CF2QCF2)
has been reported: J. A. Evans and D. R. Russell, Chem. Commun.,
1971, 197.
18 The turnover-limiting step in the catalytic cycle for conjugate
addition is known to be the transmetalation step. See ref. 8.
19 Review on the trans effect: T. G. Appleton, H. C. Clark and
L. E. Manzer, Coord. Chem. Rev., 1973, 10, 335.
ꢁc
This journal is The Royal Society of Chemistry 2009
Chem. Commun., 2009, 4815–4817 | 4817