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References and notes
OH
1. Reviews: (a) Schneider, C. Synthesis 2006, 3919; (b) Pastor, I. M.;
SePh
Yus, M. Curr. Org. Chem. 2005, 9, 1; (c) Jacobsen, E. N.; Wu, M. H.
In Comprehensive Asymmetric Catalysis; Jacobsen, E. N., Pfaltz, A.,
Yamamoto, H., Eds., 1999; Vol. 2, p 649.
4f
2. (a) Nugent, W. A. J. Am. Chem. Soc. 1992, 114, 2768; (b) Martinez, L.
E.; Leighton, J. L.; Carsten, D. H.; Jacobsen, E. N. J. Am. Chem. Soc.
1995, 117, 5897.
24% ee through ring-opening of cyclohexene oxide did not
show any tendency to undergo the deselenation reaction
even under reaction conditions B, which typically favor
the formation of the deselenated alcohols. To probe the
influence of the chiral catalyst to facilitate the deselenation
reaction we treated 1,2-seleno alcohol 4b with 2 equiv of
PhSeH with and without the chiral catalyst (Scheme 2).
In the absence of the catalyst a slow deselenation occurred
giving rise to deselenated alcohol 5b in just 25% along with
52% of recovered seleno alcohol 4b after 1 day at rt. In the
presence of either the scandium–bipyridine catalyst or sim-
ply ligand 3 alone, however, 5b was obtained in good yields
under otherwise identical reaction conditions with only
trace amounts of the starting material being recovered.
We suspect that the basic bipyridine ligand assists in the
abstraction of the selenol proton, which most likely is the
first step towards the formation of the selenol radical.
3. (a) Hou, X. L.; Wu, J.; Dai, L. X.; Xia, L. J.; Tang, M. H.
Tetrahedron: Asymmetry 1998, 9, 1747; (b) Sagawa, S.; Abe, H.; Hase,
Y.; Inaba, T. J. Org. Chem. 1999, 64, 4962; (c) Sekine, A.; Ohshima,
T.; Shibasaki, M. Tetrahedron 2002, 58, 75; (d) Azoulay, S.; Manabe,
K.; Kobayashi, S. Org. Lett. 2005, 7, 4593; (e) Ogawa, C.; Azoulay,
S.; Kobayashi, S. Heterocycles 2005, 66, 201; (f) Carree, F.; Gil, R.;
Collin, J. Org. Lett. 2005, 7, 1023; (g) Kureshy, R. I.; Singh, S.; Khan,
N. H.; Abdi, S. H. R.; Suresh, E.; Jasra, R. V. Eur. J. Org. Chem.
2006, 1303; (h) Arai, K.; Salter, M. M.; Yamashita, Y.; Kobayashi, S.
Angew. Chem. 2007, 119, 973; Angew. Chem., Int. Ed. 2007, 46, 955.
4. (a) Jacobsen, E. N.; Kakiuchi, F.; Konsler, R. G.; Larrow, J. F.;
Tokunaga, M. Tetrahedron Lett. 1997, 38, 773; (b) Matsunaga, S.;
Das, J.; Roels, J.; Vogl, E. M.; Yamamoto, N.; Iida, T.; Yamaguchi,
K.; Shibasaki, M. J. Am. Chem. Soc. 2000, 122, 2252.
5. (a) Cole, B. M.; Shimizu, K. D.; Krueger, C. A.; Harrity, J. P. A.;
Snapper, M. L.; Hoveyda, A. H. Angew. Chem. 1996, 108, 1776;
Angew. Chem., Int. Ed. 1996, 35, 1668; (b) Shimizu, K. D.; Cole, B.
M.; Krueger, C. A.; Kuntz, K. W.; Snapper, M. L.; Hoveyda, A. H.
Angew. Chem. 1997, 109, 1782; Angew. Chem., Int. Ed. 1997, 36, 1704;
(c) Schaus, S. E.; Jacobsen, E. N. Org. Lett. 2000, 2, 1001; (d) Zhu, C.;
Yuan, F.; Gu, W.; Pan, Y. Chem. Commun. 2003, 692.
6. (a) Iida, T.; Yamamoto, N.; Sasai, H.; Shibasaki, M. J. Am. Chem.
Soc. 1997, 119, 4783; (b) Wu, M. H.; Jacobsen, E. N. J. Org. Chem.
1998, 63, 5252; (c) Wu, J.; Hou, X. L.; Dai, L. X.; Xia, L. J.; Tang, M.
H. Tetrahedron: Asymmetry 1998, 9, 3431; (d) Boudou, M.; Ogawa,
C.; Kobayashi, S. Adv. Synth. Catal. 2006, 348, 2585; (e) Ogawa, C.;
Wang, N.; Kobayashi, S. Chem. Lett. 2007, 36, 34; (f) Chen, Y.-J.;
Chen, C. Tetrahedron: Asymmetry 2007, 18, 1313.
7. (a) Nugent, W. A. J. Am. Chem. Soc. 1998, 120, 7139; (b) Denmark,
S. E.; Barsanti, P. A.; Wong, K. T.; Stavenger, R. A. J. Org. Chem.
1998, 63, 2428; (c) Tao, B.; Lo, M. M. C.; Fu, G. C. J. Am. Chem.
Soc. 2001, 123, 353; (d) Nakaijama, M.; Saito, M.; Uemura, M.;
Hashimoto, S. Tetrahedron Lett. 2002, 43, 8827; (e) Tokuoka, E.;
Kotani, S.; Matsunaga, H.; Ishizuka, T.; Hashimoto, S.; Nakaijama,
M. Tetrahedron: Asymmetry 2005, 16, 2391.
4-F-Ph
4-F-Ph
OH
4-F-Ph
4-F-Ph
OH
CH2Cl2
rt, 24 h
+
PhSeH
SePh
4b
2
5b
25%
without catalyst:
with Sc(OTf)3/3: 83%
with ligand 3 alone: 65%
Scheme 2. Control experiments for the deselenation reaction.
In conclusion, we have shown that the chiral scandium–
bipyridine complex effectively catalyzed the selenol addi-
tion to aromatic meso-epoxides and furnished 1,2-seleno
alcohols in moderate to good yields and typically high
enantioselectivities. Furthermore, a sequential epoxide
opening-deselenation protocol has been developed, which
gave rise to formal hydride addition products in moderate
yields and high ee’s.
8. Yang, M.; Zhu, C.; Yuan, F.; Huang, Y.; Pan, Y. Org. Lett. 2005, 7,
1927.
9. (a) Schneider, C.; Sreekanth, A. R.; Mai, E. Angew. Chem. 2004, 116,
5809; Angew. Chem., Int. Ed 2004, 43, 5691; (b) Tscho¨p, A.; Marx, A.;
Sreekanth, A. R.; Schneider, C. Eur. J. Org. Chem. 2007, 2318.
10. (a) Mai, E.; Schneider, C. Chem. Eur. J. 2007, 13, 2729; (b) Mai, E.;
Schneider, C. Synlett 2007, 2136.
11. Nandakumar, M. V.; Tscho¨p, A.; Krautscheid, H.; Schneider, C.
Chem. Commun. 2007, 2756.
Acknowledgments
12. There is some discrepancy in the analytical data given for 1,2-seleno
alcohol 4a in Ref. 8 compared to the data we obtained for this
compound. Whereas the 1H NMR-data nicely matches our data for
4a, the given HPLC-data of compound 4a actually matches the data
of the deselenated alcohol 5a instead. This may suggest that at least in
some runs the deselenation reaction had also occurred unnoticed in
this study.
This work was generously supported by the Deutsche
Forschungsgemeinschaft (Schn 441/3-2). O.P. thanks Ohio
University (Athens, Ohio) and the DAAD for financial
support. Wacker A.G. is gratefully acknowledged for the
donation of chemicals.
13. Perkins, M. J.; Smith, B. V.; Turner, E. S. Chem. Commun. 1980,
977.
14. Experimental procedure for the selenolysis: a solution of Sc(OTf)3
(0.025 mmol) and chiral bipyridine 3 (0.030 mmol) in dry and degassed
dichloromethane (1 mL) was stirred under argon for 10 min, after
which cis-stilbene oxide (1a) (0.25 mmol) dissolved in dichloromethane
(0.5 mL) was added. Under exclusion of light the mixture was stirred
Supplementary data
Supplementary data associated with this article can be