6606
L. Mou, G. Singh / Tetrahedron Letters 42 (2001) 6603–6606
S. J.; Schmatz, D. M.; Fisher, M. H.; Wyvratt, M. J.;
Meinke, P. T. Tetrahedron Lett. 2000, 41, 7837–7841.
1527, 1214, 732; m/z [found (MH+) 350.1973, C19H28NO5
requires 350.1967].
4. For an overview of amino acid synthesis, see: Coppola,
G. M.; Shuster, H. F. Asymmetric Synthesis: Construction
of Chiral Molecules Using Amino Acids; Wiley: New
York, 1987.
5. Gramaticia, P.; Manitto, P. Tetrahedron 1986, 42, 6687–
6692.
Cyclic peptide 1 (R=Boc): mp: 72–74°C, [h]D −28.3
(c=0.6, CHCl3); lH (270 MHz, CDCl3): 0.85 (d, 3H, J
7.1 Hz, Ile); 0.92 (t, 3H, J 7.2 Hz, Ile); 1.00 (t, 3H, J
10.5Hz, Aoda);1.21–2.15 (m, 17H, 6Pip+3Ile+8Aoda),
1.68 (s, 9H, Boc), 2.33 (t, 2H, J 7.2 Hz, Aoda), 2.38 (q,
2H, J 7.4 Hz, Aoda), 3.02 (brt, 1H, J 13.1 Hz, Pip), 3.43
(dd, 1H, J 14.5, 5.8 Hz, Trp), 3.76 (dd, 1H, J 15.0,10.0
Hz, Trp), 4.01–4.06 (m, 1H, Trp), 4.20 (brt, 1H, J 10.0
Hz, Aoda), 4.28–4.41 (m, 1H, Pip), 4.73 (t, 1H, J 10.0 Hz,
Ile), 5.08 (brd, 1H, J 4.0 Hz, Pip), 6.47 (d, NH, J 10.5
Hz), 6.66 (d, NH, J 10.0 Hz), 7.22 (dt, 1H, J 7.5, 1.5 Hz,
Trp), 7.30 (dt, 1H, J 8.4,1.6 Hz, Trp), 7.38 (d, 1H, J 8.4
Hz, Trp), 7.43 (brs, 1H, Trp), 7.52 (d, 1H, J 8.4 Hz, Trp),
8.1 (d, 1H, NH, J 7.8 Hz); m/z [Found (MH+) 694.4171
C38H56N5O7 requires 694.4180].
6. Lai, Y.-H. Synthesis 1981, 585–603.
7. (a) Dunn, M. J.; Jackson, R. F. W. J. Org. Chem. 1995,
60, 2210–2215 and references cited therein; (b) Ye, B.;
Burke, Jr., T. R. J. Org. Chem. 1995, 60, 2640–2641; (c)
Reiber, M.; Mass, G. Synthesis 1998, 1129–1132.
8. Barton, D. H. R.; Lacher, B.; Zard, S. Z. Tetrahedron
1987, 43, 4321–4328.
9. (a) Weitz, I. S.; Pellegrini, M.; Mierke, D. F.; Chorer, M.
J. Org. Chem. 1997, 62, 2527–2534; (b) Vasella, A.;
Voeffray, R.; Pless, J.; Hugenin, R. Helv. Chim. Acta
1983, 66, 1241–1252; (c) Valerio, R. M.; Alewood, P. F.;
Johns, R. B. Synthesis 1988, 786–789.
10. Physical data. All new compounds gave satisfactory spec-
tral, microanalytical and/or high-resolution mass spectral
data. 15, [h]D +10.0 (c=0.4, CHCl3); lH (270 MHz,
CDCl3): 1.04 (t, 3H, J 7.2 Hz), 1.22–1.32 (m, 4H),
1.59–1.80 (m, 4H), 2.36–2.45 (m, 4H), 3.74 (s, 3H),
4.31–4.38 (m, 1H), 5.11 (s, 2H), 5.25 (br. d, 1H, J 8.5
Hz), 7.28–7.37 (m, 5H); lC (67.8 MHz, CDCl3): 7.70,
23.37, 24.87, 28.58, 32.33, 35.79, 41.99, 52.27, 53.62,
66.85, 128.03, 128.10, 128.42, 128.44, 128.45, 136.13,
155.80, 172.95, 211.62; wmax (thin film) 3347, 1735, 1712,
11. Robertson, A. V.; Marion, L. Can. J. Chem. 1959, 37,
828–830.
12. (a) Pastuszak, J.; Gardner, J. H.; Singh, J. J. Am. Chem.
Soc. 1992, 114, 10181–10189; (b) Heffner, R. J.; Jiang, J.;
Joullie, M. M. J. Org. Chem. 1982, 47, 2982–2987.
13. (a) Christopher, D. J. B.; Norley, M.; Pattenden, G. J.
Chem. Soc., Perkin. Trans. 1 2000, 883–888; (b) Christo-
pher, D. J. B.; Pattenden, G. J. Chem. Soc., Perkin.
Trans. 1 2000, 875–882.
14. Wenger, R. M. Helv. Chim. Acta 1984, 67, 508–525.
15. (a) Schmidt, U.; Schanbacher, U. Angew. Chem., Int. Ed.
Engl. 1981, 20, 1026–1027; (b) Schmidt, U.; Lieberknecht,
A. Synthesis 1986, 361–366.