Asymmetric aminohydroxylation of substituted styrenes: applications in the synthesis of enantiomerically enriched arylglycinols and a diamine

Abstract

The catalytic asymmetric aminohydroxylation of a variety of styrene derivatives and vinyl aromatics using osmium tetroxide in conjunction with alkaloid-derived ligands [e.g. (DHQ)₂PHAL or (DHQD)₂PHAL] and haloamine salts of alkyl carbamates (e.g. ethyl carbamate or tert-butyl carbamate) has been investigated. By observing the effect of different aromatic substituents and alkyl carbamates on the regioselectivity, yield and enantioselectivity of the aminohydroxylation reactions, a number of conclusions have been reached: (i) the 1-aryl-2-hydroxyethylamine regioisomers were obtained as the major products in reasonable yield and high (⩾87%) enantiomeric excess; (ii) tert-butyl carbamate was superior to ethyl carbamate in terms of yield, enantioselectivity and ease of removal of the N-protecting group; (iii) high (⩾96%) enantioselectivity was observed with a 4-methoxy-substituted styrene whereas ortho-substituted styrenes gave lower enantioselectivities; (iv) chiral ligands (DHQ)₂PHAL and (DHQD)₂PHAL gave essentially equal and opposite senses and degrees of asymmetric induction; (v) regioselectivity was ligand dependent with better regioselectivity (and therefore higher isolated yields) obtained with (DHQ)₂PHAL than with (DHQD)₂PHAL. The products of the aminohydroxylation reactions were used to prepare enantiomerically enriched arylglycinols and a chiral diamine.

References

1. For commentaries, see: (a) O. Reiser, Angew. Chem., Int. Ed. Engl., 1996, 35, 1308; (b) G. Casiraghi, G. Rassu and F. Zanardi, Chemtracts: Org. Chem., 1997, 10, 318.
2. (a) G. Li, H.-T. Chang and K. B. Sharpless, Angew. Chem., Int. Ed. Engl., 1996, 35, 451; (b) J. Rudolph, P. C. Sennhenn, C. P. Vlaar and K. B. Sharpless, Angew. Chem., Int. Ed. Engl., 1996, 35, 2810; (c) A. E. Rubin and K. B. Sharpless, Angew. Chem., Int. Ed. Engl., 1997, 36, 2637.
3. (a) G. Li, H. H. Angert and K. B. Sharpless, Angew. Chem., Int. Ed. Engl., 1996, 35, 2813; (b) K. L. Reddy, K. R. Dress and K. B. Sharpless, Tetrahedron Lett., 1998, 39, 3667.
4. M. Bruncko, G. Schlingloff and K. B. Sharpless, Angew. Chem., Int. Ed. Engl., 1997, 36, 1483.
5. K. L. Reddy and K. B. Sharpless, J. Am. Chem. Soc., 1998, 120, 1207.
6. G. Li and K. B. Sharpless, Acta Chem. Scand., 1996, 50, 649.
7. R. Angelaud, Y. Landais and K. Schenk, Tetrahedron Lett., 1997, 38, 1407.
8. T. T. Upadhya and A. Sudalai, Tetrahedron: Asymmetry, 1997, 8, 3685.
9. H. Han, J. Yoon and K. D. Janda, J. Org. Chem., 1998, 63, 2045.
10. P. Phukan and A. Sudalai, Tetrahedron: Asymmetry, 1998, 9, 1001.
11. G. Cravotto, G. B. Giovenzana, R. Pagliarin, G. Palmisano and M. Sisti, Tetrahedron: Asymmetry, 1998, 9, 745.
12. Preliminary communication: P. O'Brien, S. A. Osborne and D. D. Parker, Tetrahedron Lett., 1998, 39, 4099.
13. (a) S. E. de Sousa, P. O'Brien and P. Poumellec, Tetrahedron: Asymmetry, 1997, 8, 2613; (b) S. E. de Sousa and P. O'Brien, Tetrahedron Lett., 1997, 38, 4885; (c) P. O'Brien and P. Poumellec, Tetrahedron Lett., 1996, 37, 5619.
14. S. E. de Sousa, P. O'Brien and P. Poumellec, J. Chem. Soc., Perkin Trans. 1, 1998, 1483.
15. H. C. Kolb, M. S. Van Nieuwenhze and K. B. Sharpless, Chem. Rev., 1994, 94, 2483.
16. G. Miao and B. E. Rossiter, J. Org. Chem., 1995, 60, 8424.
17. N. Lewis, A. McKillop, R. J. K. Taylor and R. J. Watson, Synth. Commun., 1995, 25, 561.
18. T. Izumi and K. Fukaya, Bull. Chem. Soc. Jpn., 1993, 66, 1216.
19. T. W. Greene and P. G. M. Wuts, Protecting Groups in Organic Synthesis, Wiley, New York, 1991.
20. K. B. Sharpless, personal communication.
21. J.-N. Denis, A. Correa and A. E. Greene, J. Org. Chem., 1991, 56, 6939.
22. (a) H. Matsunaga, T. Ishizuka and T. Kunieda, Tetrahedron, 1997, 53, 1275; (b) R. Caputo, E. Cassano, L. Longobardo and G. Palumbo, Tetrahedron, 1995, 51, 12 337.
23. M. A. Tschantz, L. E. Burgess and A. I. Meyers, Org. Synth., 1996, 73, 221.
24. F. Matsuura, Y. Hamada and T. Shioiri, Tetrahedron, 1994, 50, 9457.
25. B. Tao, G. Schlingloff and K. B. Sharpless, Tetrahedron Lett., 1998, 39, 2507.
26. H. Becker and K. B. Sharpless, Angew. Chem., Int. Ed. Engl., 1996, 35, 448.
27. R. M. Williams, P. P. Ehrlich, W. Zhai and J. Hendrix, J. Org. Chem., 1987, 52, 2615.
28. K.-I. Kawasaki and T. Katsuki, Tetrahedron, 1997, 53, 6337.
29. W. C. Still, M. Kahn and A. Mitra, J. Org. Chem., 1978, 43, 2923.
30. M. J. Mintz and C. Walling, Org. Synth., 1983, Coll. Vol. V, 183.