Diastereo- and enantioselective synthesis of differently N,O-protected 1,3-amino alcohols with three neighbouring stereogenic centers

Synthesis

Volumn , Issue 12, 2004, Pages 2040-2046

  Enders, Dieter ^a   Moser, Michael ^a   Geibel, Gunter ^a   Laufer, Monika C ^a  

^a RWTH AACHEN UNIVERSITY   (Germany)

Author keywords

1,3 amino alcohols; Aldol reaction; Hydrazones; N N bond cleavage; Nucleophilic addition

Indexed keywords

ENANTIOSELECTIVE SYNTHESIS; STEREOGENIC CENTERS;

ALCOHOLS; ALDEHYDES; TITANIUM COMPOUNDS;

NITROGEN COMPOUNDS;

ALCOHOL DERIVATIVE; HETEROCYCLIC COMPOUND; HYDRAZONE DERIVATIVE; NITROGEN; OXYGEN; TITANIUM TETRACHLORIDE;

ADDITION REACTION; ALDOL REACTION; ARTICLE; CHEMICAL BOND; DIASTEREOISOMER; ENANTIOMER; ENANTIOSELECTIVITY; REDUCTION; STEREOCHEMISTRY; SYNTHESIS;

EID: 4444243696     PISSN: 00397881     EISSN: None     Source Type: Journal    
DOI: 10.1055/s-2004-829142     Document Type: Article

References (56)

1. For typical examples, see: (a) Kozikowski, A. P.; Chen, Y.-Y. J. Org. Chem. 1981, 46, 5248. (b) Wang, Y.-F.; Izawa, T.; Kobayashi, S.; Ohno, M. J. Am. Chem. Soc. 1982, 104, 6465. (c) Hashiguchi, S.; Kawada, A.; Natsugari, H. J. Chem. Soc., Perkin Trans. 1 1991, 2435. (d) Knapp, S. Chem. Rev. 1995, 95, 1859. (e) Sakai, R.; Kamiya, H.; Murata, M.; Shimamoto, K. J. Am. Chem. Soc. 1997, 119, 4112. (f) Carlier, P. R.; Lo, M. M.-C.; Lo, P. C.-K.; Richelson, E.; Tatsumi, M.; Reynolds, I. J.; Sharma, T. A. Bioorg. Med. Chem. Lett. 1998, 8, 487. (g) Gais, H.-J.; Griebel, C.; Buschmann, H. Tetrahedron: Asymmetry 2000, 11, 917. (h) Benedetti, F.; Norbedo, S. Chem. Commun. 2001, 203.
2. For typical examples, see: (a) Kozikowski, A. P.; Chen, Y.-Y. J. Org. Chem. 1981, 46, 5248. (b) Wang, Y.-F.; Izawa, T.; Kobayashi, S.; Ohno, M. J. Am. Chem. Soc. 1982, 104, 6465. (c) Hashiguchi, S.; Kawada, A.; Natsugari, H. J. Chem. Soc., Perkin Trans. 1 1991, 2435. (d) Knapp, S. Chem. Rev. 1995, 95, 1859. (e) Sakai, R.; Kamiya, H.; Murata, M.; Shimamoto, K. J. Am. Chem. Soc. 1997, 119, 4112. (f) Carlier, P. R.; Lo, M. M.-C.; Lo, P. C.-K.; Richelson, E.; Tatsumi, M.; Reynolds, I. J.; Sharma, T. A. Bioorg. Med. Chem. Lett. 1998, 8, 487. (g) Gais, H.-J.; Griebel, C.; Buschmann, H. Tetrahedron: Asymmetry 2000, 11, 917. (h) Benedetti, F.; Norbedo, S. Chem. Commun. 2001, 203.
3. For typical examples, see: (a) Kozikowski, A. P.; Chen, Y.-Y. J. Org. Chem. 1981, 46, 5248. (b) Wang, Y.-F.; Izawa, T.; Kobayashi, S.; Ohno, M. J. Am. Chem. Soc. 1982, 104, 6465. (c) Hashiguchi, S.; Kawada, A.; Natsugari, H. J. Chem. Soc., Perkin Trans. 1 1991, 2435. (d) Knapp, S. Chem. Rev. 1995, 95, 1859. (e) Sakai, R.; Kamiya, H.; Murata, M.; Shimamoto, K. J. Am. Chem. Soc. 1997, 119, 4112. (f) Carlier, P. R.; Lo, M. M.-C.; Lo, P. C.-K.; Richelson, E.; Tatsumi, M.; Reynolds, I. J.; Sharma, T. A. Bioorg. Med. Chem. Lett. 1998, 8, 487. (g) Gais, H.-J.; Griebel, C.; Buschmann, H. Tetrahedron: Asymmetry 2000, 11, 917. (h) Benedetti, F.; Norbedo, S. Chem. Commun. 2001, 203.
4. For typical examples, see: (a) Kozikowski, A. P.; Chen, Y.-Y. J. Org. Chem. 1981, 46, 5248. (b) Wang, Y.-F.; Izawa, T.; Kobayashi, S.; Ohno, M. J. Am. Chem. Soc. 1982, 104, 6465. (c) Hashiguchi, S.; Kawada, A.; Natsugari, H. J. Chem. Soc., Perkin Trans. 1 1991, 2435. (d) Knapp, S. Chem. Rev. 1995, 95, 1859. (e) Sakai, R.; Kamiya, H.; Murata, M.; Shimamoto, K. J. Am. Chem. Soc. 1997, 119, 4112. (f) Carlier, P. R.; Lo, M. M.-C.; Lo, P. C.-K.; Richelson, E.; Tatsumi, M.; Reynolds, I. J.; Sharma, T. A. Bioorg. Med. Chem. Lett. 1998, 8, 487. (g) Gais, H.-J.; Griebel, C.; Buschmann, H. Tetrahedron: Asymmetry 2000, 11, 917. (h) Benedetti, F.; Norbedo, S. Chem. Commun. 2001, 203.
5. For typical examples, see: (a) Kozikowski, A. P.; Chen, Y.-Y. J. Org. Chem. 1981, 46, 5248. (b) Wang, Y.-F.; Izawa, T.; Kobayashi, S.; Ohno, M. J. Am. Chem. Soc. 1982, 104, 6465. (c) Hashiguchi, S.; Kawada, A.; Natsugari, H. J. Chem. Soc., Perkin Trans. 1 1991, 2435. (d) Knapp, S. Chem. Rev. 1995, 95, 1859. (e) Sakai, R.; Kamiya, H.; Murata, M.; Shimamoto, K. J. Am. Chem. Soc. 1997, 119, 4112. (f) Carlier, P. R.; Lo, M. M.-C.; Lo, P. C.-K.; Richelson, E.; Tatsumi, M.; Reynolds, I. J.; Sharma, T. A. Bioorg. Med. Chem. Lett. 1998, 8, 487. (g) Gais, H.-J.; Griebel, C.; Buschmann, H. Tetrahedron: Asymmetry 2000, 11, 917. (h) Benedetti, F.; Norbedo, S. Chem. Commun. 2001, 203.
6. For typical examples, see: (a) Kozikowski, A. P.; Chen, Y.-Y. J. Org. Chem. 1981, 46, 5248. (b) Wang, Y.-F.; Izawa, T.; Kobayashi, S.; Ohno, M. J. Am. Chem. Soc. 1982, 104, 6465. (c) Hashiguchi, S.; Kawada, A.; Natsugari, H. J. Chem. Soc., Perkin Trans. 1 1991, 2435. (d) Knapp, S. Chem. Rev. 1995, 95, 1859. (e) Sakai, R.; Kamiya, H.; Murata, M.; Shimamoto, K. J. Am. Chem. Soc. 1997, 119, 4112. (f) Carlier, P. R.; Lo, M. M.-C.; Lo, P. C.-K.; Richelson, E.; Tatsumi, M.; Reynolds, I. J.; Sharma, T. A. Bioorg. Med. Chem. Lett. 1998, 8, 487. (g) Gais, H.-J.; Griebel, C.; Buschmann, H. Tetrahedron: Asymmetry 2000, 11, 917. (h) Benedetti, F.; Norbedo, S. Chem. Commun. 2001, 203.
7. For typical examples, see: (a) Kozikowski, A. P.; Chen, Y.-Y. J. Org. Chem. 1981, 46, 5248. (b) Wang, Y.-F.; Izawa, T.; Kobayashi, S.; Ohno, M. J. Am. Chem. Soc. 1982, 104, 6465. (c) Hashiguchi, S.; Kawada, A.; Natsugari, H. J. Chem. Soc., Perkin Trans. 1 1991, 2435. (d) Knapp, S. Chem. Rev. 1995, 95, 1859. (e) Sakai, R.; Kamiya, H.; Murata, M.; Shimamoto, K. J. Am. Chem. Soc. 1997, 119, 4112. (f) Carlier, P. R.; Lo, M. M.-C.; Lo, P. C.-K.; Richelson, E.; Tatsumi, M.; Reynolds, I. J.; Sharma, T. A. Bioorg. Med. Chem. Lett. 1998, 8, 487. (g) Gais, H.-J.; Griebel, C.; Buschmann, H. Tetrahedron: Asymmetry 2000, 11, 917. (h) Benedetti, F.; Norbedo, S. Chem. Commun. 2001, 203.
8. For typical examples, see: (a) Kozikowski, A. P.; Chen, Y.-Y. J. Org. Chem. 1981, 46, 5248. (b) Wang, Y.-F.; Izawa, T.; Kobayashi, S.; Ohno, M. J. Am. Chem. Soc. 1982, 104, 6465. (c) Hashiguchi, S.; Kawada, A.; Natsugari, H. J. Chem. Soc., Perkin Trans. 1 1991, 2435. (d) Knapp, S. Chem. Rev. 1995, 95, 1859. (e) Sakai, R.; Kamiya, H.; Murata, M.; Shimamoto, K. J. Am. Chem. Soc. 1997, 119, 4112. (f) Carlier, P. R.; Lo, M. M.-C.; Lo, P. C.-K.; Richelson, E.; Tatsumi, M.; Reynolds, I. J.; Sharma, T. A. Bioorg. Med. Chem. Lett. 1998, 8, 487. (g) Gais, H.-J.; Griebel, C.; Buschmann, H. Tetrahedron: Asymmetry 2000, 11, 917. (h) Benedetti, F.; Norbedo, S. Chem. Commun. 2001, 203.
9. (a) Oppolzer, W.; Radinov, R. N. Tetrahedron Lett. 1988, 29, 5645.
10. (b) Cho, B. T.; Kim, N. Tetrahedron Lett. 1994, 35, 4115.
11. (c) Cicchi, S.; Crea, S.; Goti, A.; Brandi, A. Tetrahedron: Asymmetry 1997, 8, 293.
12. Li, X.; Yeung, C.; Chan, A. S. C.; Yang, T.-K. Tetrahedron: Asymmetry 1999, 10, 759.
13. Cohen, N.; Lopresti, R. J.; Neukom, C.; Saucy, G. J. Org. Chem. 1980, 45, 582.
14. (a) Notz, W.; Tanaka, F.; Watanabe, S.; Chowdari, N. S.; Turner, J. M.; Thayumanavan, R.; Barbas, C. F. III J. Org. Chem. 2003, 68, 9624.
15. (b) Kochi, T.; Tang, T. P.; Ellman, J. A. J. Am. Chem. Soc. 2003, 125, 11276.
16. (c) Kochi, T.; Tang, T. P.; Ellman, J. A. J. Am. Chem. Soc. 2002, 124, 6518.
17. (d) Calmes, M.; Escale, F.; Martinez, J. Synthesis 2001, 1302.
18. (e) Veenstra, S. J.; Kinderman, S. S. Synlett 2001, 1109.
19. (f) Toujas, J.-L.; Toupet, L.; Vaultier, M. Tetrahedron 2000, 56, 2665.
20. (g) Lutz, C.; Lutz, V.; Knochel, P. Tetrahedron 1998, 54, 6385.
21. (h) Hashiguchi, S.; Kawada, A.; Natsugari, H. Synthesis 1992, 403.
22. (i) Wanner, K. T.; Höfner, G. Tetrahedron 1991, 47, 1895.
23. (j) Gassman, P. G.; Haberman, L. M. Tetrahedron Lett. 1985, 26, 4971.
24. (k) Annunziata, R.; Cinquini, M.; Cozzi, F.; Restelli, A. J. Chem. Soc., Perkin Trans. 1 1985, 2293.
25. (l) Jäger, V.; Müller, I.; Schohe, R.; Frey, M.; Ehrler, R.; Häfele, B.; Schröter, D. Lect. Heterocycl. Chem. 1985, 8, 79.
26. (m) Jäger, V.; Schwab, W.; Buß, V. Angew. Chem. Int. Ed. 1981, 20, 601; Angew. Chem. 1981, 93, 576.
27. (m) Jäger, V.; Schwab, W.; Buß, V. Angew. Chem. Int. Ed. 1981, 20, 601; Angew. Chem. 1981, 93, 576.
28. (a) Barluenga, J.; Joglar, J.; Gonzáles, F. J.; Fustero, S. Tetrahedron Lett. 1989, 30, 2001.
29. (b) Barluenga, J.; Fustero, S.; Olano, B.; Viado, A. L. J. Org. Chem. 1992, 57, 1219.
30. (c) Kossenjans, M.; Martens, J. Tetrahedron: Asymmetry 1999, 10, 3409.
31. (d) Ohno, H.; Hamaguchi, H.; Tanaka, T. J. Org. Chem. 2001, 66, 1867.
32. (e) Takemoto, Y.; Anzai, M.; Yanada, R.; Fujii, N.; Ohno, H.; Ibuka, T. Tetrahedron Lett. 2001, 42, 1725.
33. (f) Gais, H.-J.; Loo, R.; Roder, D.; Das, P.; Raabe, G. Eur. J. Org. Chem. 2003, 1500.
34. For some recent reviews and accounts, see: (a) Palomo, C.; Oiarbide, M.; García, J. M. Chem.-Eur. J. 2002, 8, 37. (b) Alcaide, B.; Almendros, P. Eur. J. Org. Chem. 2002, 1595. (c) Machajewski, T. D.; Wong, C.-H. Angew. Chem. Int. Ed. 2000, 39, 1352; Angew. Chem. 2000, 112, 1407. (d) Denmark, S. E.; Stavenger, R. A. Acc. Chem. Res. 2000, 33, 432. (e) Carreira, E. M. In Comprehensive Asymmetric Catalysis, Vol. 3; Jacobsen, E. N.; Pfaltz, A.; Yamamoto, H., Eds.; Springer: Heidelberg, 1999, 997. (f) Mahrwald, R. Chem. Rev. 1999, 99, 1095. (g) Nelson, S. G. Tetrahedron: Asymmetry 1998, 9, 357. (h) Gröger, H.; Vogl, E. M.; Shibasaki, M. Chem.-Eur. J. 1998, 4, 1137.
35. For some recent reviews and accounts, see: (a) Palomo, C.; Oiarbide, M.; García, J. M. Chem.-Eur. J. 2002, 8, 37. (b) Alcaide, B.; Almendros, P. Eur. J. Org. Chem. 2002, 1595. (c) Machajewski, T. D.; Wong, C.-H. Angew. Chem. Int. Ed. 2000, 39, 1352; Angew. Chem. 2000, 112, 1407. (d) Denmark, S. E.; Stavenger, R. A. Acc. Chem. Res. 2000, 33, 432. (e) Carreira, E. M. In Comprehensive Asymmetric Catalysis, Vol. 3; Jacobsen, E. N.; Pfaltz, A.; Yamamoto, H., Eds.; Springer: Heidelberg, 1999, 997. (f) Mahrwald, R. Chem. Rev. 1999, 99, 1095. (g) Nelson, S. G. Tetrahedron: Asymmetry 1998, 9, 357. (h) Gröger, H.; Vogl, E. M.; Shibasaki, M. Chem.-Eur. J. 1998, 4, 1137.
36. For some recent reviews and accounts, see: (a) Palomo, C.; Oiarbide, M.; García, J. M. Chem.-Eur. J. 2002, 8, 37. (b) Alcaide, B.; Almendros, P. Eur. J. Org. Chem. 2002, 1595. (c) Machajewski, T. D.; Wong, C.-H. Angew. Chem. Int. Ed. 2000, 39, 1352; Angew. Chem. 2000, 112, 1407. (d) Denmark, S. E.; Stavenger, R. A. Acc. Chem. Res. 2000, 33, 432. (e) Carreira, E. M. In Comprehensive Asymmetric Catalysis, Vol. 3; Jacobsen, E. N.; Pfaltz, A.; Yamamoto, H., Eds.; Springer: Heidelberg, 1999, 997. (f) Mahrwald, R. Chem. Rev. 1999, 99, 1095. (g) Nelson, S. G. Tetrahedron: Asymmetry 1998, 9, 357. (h) Gröger, H.; Vogl, E. M.; Shibasaki, M. Chem.-Eur. J. 1998, 4, 1137.
37. For some recent reviews and accounts, see: (a) Palomo, C.; Oiarbide, M.; García, J. M. Chem.-Eur. J. 2002, 8, 37. (b) Alcaide, B.; Almendros, P. Eur. J. Org. Chem. 2002, 1595. (c) Machajewski, T. D.; Wong, C.-H. Angew. Chem. Int. Ed. 2000, 39, 1352; Angew. Chem. 2000, 112, 1407. (d) Denmark, S. E.; Stavenger, R. A. Acc. Chem. Res. 2000, 33, 432. (e) Carreira, E. M. In Comprehensive Asymmetric Catalysis, Vol. 3; Jacobsen, E. N.; Pfaltz, A.; Yamamoto, H., Eds.; Springer: Heidelberg, 1999, 997. (f) Mahrwald, R. Chem. Rev. 1999, 99, 1095. (g) Nelson, S. G. Tetrahedron: Asymmetry 1998, 9, 357. (h) Gröger, H.; Vogl, E. M.; Shibasaki, M. Chem.-Eur. J. 1998, 4, 1137.
38. For some recent reviews and accounts, see: (a) Palomo, C.; Oiarbide, M.; García, J. M. Chem.-Eur. J. 2002, 8, 37. (b) Alcaide, B.; Almendros, P. Eur. J. Org. Chem. 2002, 1595. (c) Machajewski, T. D.; Wong, C.-H. Angew. Chem. Int. Ed. 2000, 39, 1352; Angew. Chem. 2000, 112, 1407. (d) Denmark, S. E.; Stavenger, R. A. Acc. Chem. Res. 2000, 33, 432. (e) Carreira, E. M. In Comprehensive Asymmetric Catalysis, Vol. 3; Jacobsen, E. N.; Pfaltz, A.; Yamamoto, H., Eds.; Springer: Heidelberg, 1999, 997. (f) Mahrwald, R. Chem. Rev. 1999, 99, 1095. (g) Nelson, S. G. Tetrahedron: Asymmetry 1998, 9, 357. (h) Gröger, H.; Vogl, E. M.; Shibasaki, M. Chem.-Eur. J. 1998, 4, 1137.
39. For some recent reviews and accounts, see: (a) Palomo, C.; Oiarbide, M.; García, J. M. Chem.-Eur. J. 2002, 8, 37. (b) Alcaide, B.; Almendros, P. Eur. J. Org. Chem. 2002, 1595. (c) Machajewski, T. D.; Wong, C.-H. Angew. Chem. Int. Ed. 2000, 39, 1352; Angew. Chem. 2000, 112, 1407. (d) Denmark, S. E.; Stavenger, R. A. Acc. Chem. Res. 2000, 33, 432. (e) Carreira, E. M. In Comprehensive Asymmetric Catalysis, Vol. 3; Jacobsen, E. N.; Pfaltz, A.; Yamamoto, H., Eds.; Springer: Heidelberg, 1999, 997. (f) Mahrwald, R. Chem. Rev. 1999, 99, 1095. (g) Nelson, S. G. Tetrahedron: Asymmetry 1998, 9, 357. (h) Gröger, H.; Vogl, E. M.; Shibasaki, M. Chem.-Eur. J. 1998, 4, 1137.
40. For some recent reviews and accounts, see: (a) Palomo, C.; Oiarbide, M.; García, J. M. Chem.-Eur. J. 2002, 8, 37. (b) Alcaide, B.; Almendros, P. Eur. J. Org. Chem. 2002, 1595. (c) Machajewski, T. D.; Wong, C.-H. Angew. Chem. Int. Ed. 2000, 39, 1352; Angew. Chem. 2000, 112, 1407. (d) Denmark, S. E.; Stavenger, R. A. Acc. Chem. Res. 2000, 33, 432. (e) Carreira, E. M. In Comprehensive Asymmetric Catalysis, Vol. 3; Jacobsen, E. N.; Pfaltz, A.; Yamamoto, H., Eds.; Springer: Heidelberg, 1999, 997. (f) Mahrwald, R. Chem. Rev. 1999, 99, 1095. (g) Nelson, S. G. Tetrahedron: Asymmetry 1998, 9, 357. (h) Gröger, H.; Vogl, E. M.; Shibasaki, M. Chem.-Eur. J. 1998, 4, 1137.
41. For some recent reviews and accounts, see: (a) Palomo, C.; Oiarbide, M.; García, J. M. Chem.-Eur. J. 2002, 8, 37. (b) Alcaide, B.; Almendros, P. Eur. J. Org. Chem. 2002, 1595. (c) Machajewski, T. D.; Wong, C.-H. Angew. Chem. Int. Ed. 2000, 39, 1352; Angew. Chem. 2000, 112, 1407. (d) Denmark, S. E.; Stavenger, R. A. Acc. Chem. Res. 2000, 33, 432. (e) Carreira, E. M. In Comprehensive Asymmetric Catalysis, Vol. 3; Jacobsen, E. N.; Pfaltz, A.; Yamamoto, H., Eds.; Springer: Heidelberg, 1999, 997. (f) Mahrwald, R. Chem. Rev. 1999, 99, 1095. (g) Nelson, S. G. Tetrahedron: Asymmetry 1998, 9, 357. (h) Gröger, H.; Vogl, E. M.; Shibasaki, M. Chem.-Eur. J. 1998, 4, 1137.
42. For some recent reviews and accounts, see: (a) Palomo, C.; Oiarbide, M.; García, J. M. Chem.-Eur. J. 2002, 8, 37. (b) Alcaide, B.; Almendros, P. Eur. J. Org. Chem. 2002, 1595. (c) Machajewski, T. D.; Wong, C.-H. Angew. Chem. Int. Ed. 2000, 39, 1352; Angew. Chem. 2000, 112, 1407. (d) Denmark, S. E.; Stavenger, R. A. Acc. Chem. Res. 2000, 33, 432. (e) Carreira, E. M. In Comprehensive Asymmetric Catalysis, Vol. 3; Jacobsen, E. N.; Pfaltz, A.; Yamamoto, H., Eds.; Springer: Heidelberg, 1999, 997. (f) Mahrwald, R. Chem. Rev. 1999, 99, 1095. (g) Nelson, S. G. Tetrahedron: Asymmetry 1998, 9, 357. (h) Gröger, H.; Vogl, E. M.; Shibasaki, M. Chem.-Eur. J. 1998, 4, 1137.
43. (a) Harrison, C. R. Tetrahedron Lett. 1987, 28, 4135.
44. (b) Evans, D. A.; Clark, J. S.; Metternich, R.; Novack, V. J.; Sheppard, G. S. J. Am. Chem. Soc. 1990, 112, 866.
45. (c) Evans, D. A.; Rieger, D. L.; Bilodeau, M. T.; Urpi, F. J. Am. Chem. Soc. 1991, 113, 1047.
46. (d) Yoshida, Y.; Hayashi, R.; Sumihara, H.; Tanabe, Y. Tetrahedron Lett. 1997, 38, 8727.
47. (a) Recent review on the SAMP/RAMP-hydrazone methodology: Job, A.; Janeck, C. F.; Bettray, W.; Peters, R.; Enders, D. Tetrahedron 2002, 58, 2253.
48. (b) Geibel, G. PhD Dissertation; RWTH Aachen University: Germany, 1997.
49. (c) Laufer, M. C. Diploma work; RWTH Aachen University: Germany, 2000.
50. Review: Enders, D.; Reinhold, U. Tetrahedron: Asymmetry 1997, 8, 1895.
51. (a) Lombardo, L. Tetrahedron Lett. 1984, 25, 227.
52. (b) Corey, E. J.; Venkateswarlu, A. J. Am. Chem. Soc. 1972, 94, 6190.
53. (a) Imamoto, T.; Takiyama, N.; Nakamura, K. Tetrahedron Lett. 1985, 26, 4763.
54. (b) Imamoto, T.; Kusumoto, T.; Tawarayama, Y.; Sugiura, Y.; Mita, T.; Hatanaka, Y.; Yokoyama, M. J. Org. Chem. 1984, 49, 3904.
55. Enders, D.; Meiers, M. Synthesis 2002, 2542; and references cited therein.
56. Enders, D.; Geibel, G.; Osborne, S. Chem.-Eur. J. 2000, 6, 1302.