7804
Y. Wang et al. / Tetrahedron Letters 42 (2001) 7801–7804
7. Uhlmann, E.; Hornung, L.; Will, D. W.; Gra¨fe, U.
C-8%), 74.79 (d, C-8), 75.16 (d, C-6%), 76.56 (d, C-6), 80.06
(d, C-13), 80.22 (d, C-3), 81.06 (d, C-10), 82.34 (d, C-3%),
173.54 (s, C-1%), 174.88 (s, C-1); NOESY (500 MHz,
acetone-d6, excess CF3CO2D) diagnostic NOE’s observed
between 2-H and 3-H, 12%-H and 3%-H, 19-H and 20-H,
Nucleosides Nucleotides 1998, 17, 309–316.
8. Inanaga, J.; Hirata, K.; Saeki, H.; Katsuki, T.;
Yamaguchi, M. Bull. Chem. Soc. Jpn. 1979, 52, 1989–
1993.
1
9. After reduction of an analytical sample of the mixture of
hydroxy acids 10 and 10% with lithium aluminum hydride
to give the corresponding diols and subsequent silylation
using excess MSTFA, capillary GC analysis showed a
single peak for the larger diol derivative, whereas two
peaks (ca. 2:1) were found for the smaller diol derivative.
10. Mulzer, J.; Kirstein, H. M.; Buschmann, J.; Lehmann,
C.; Luger, P. J. Am. Chem. Soc. 1991, 113, 910–923.
11. Compound 11: [h]2D5=+11.4 (c 0.95, CH2Cl2); 13C NMR
(125.8 MHz, acetone-d6, excess CF3CO2D): l 8.00 (q,
C-19), 8.82 (q, C-12%), 9.63 (q, C-21), 10.16 (q, C-20),
13.98 (q, C-18), 14.26 (q, C-11%), 18.98 (t, C-10%), 20.34 (t,
C-17), 27.78 (t, C-4%), 28.02 (t, C-5), 28.71 (t, C-4), 29.06
(t, C-16), 30.02 (t, C-11), 31.62 (t, C-12), 32.24 (t, C-5%),
34.38 (t, C-14), 36.58 (q, NCH3), 36.93 (d, C-7), 38.07 (t,
C-9%), 39.77 (t, C-7%), 41.36 (d, C-9), 42.02 (d, C-2), 42.20
(d, C-2%), 43.76 (q, NCH3), 68.63 (d, C-15), 71.99 (d,
C-8%), 75.26 (d, C-6%), 75.43 (d, C-8), 77.11 (d, C-6), 79.29
(d, C-3%), 79.98 (d, C-13), 80.23 (d, C-3), 81.04 (d, C-10),
174.67 (s, C-1), 174.90 (s, C-1%); NOESY (500 MHz,
acetone-d6, excess CF3CO2D) diagnostic NOE’s observed
12%-H and 21-H. H and 13C signals were assigned by 2D
NMR (COSY, HSQC, HMBC) spectra.
13. (a) Fleming, I.; Ghosh, S. K. J. Chem. Soc., Perkin Trans.
1 1998, 2733–2747; (b) Sakurai, Y.; Hikota, M.; Horita,
K.; Yonemitsu, O. Chem. Pharm. Bull. 1992, 40, 2540–
2542; (c) Hikota, M.; Tone, H.; Horita, K.; Yonemitsu,
O. Tetrahedron 1990, 31, 4613–4628.
14. Molecular modeling studies with MM2 (CS Chem3D
Pro, version 5.0; CambridgeSoft Corporation, Cam-
bridge, MA, USA) of the C(2) enol of 11 indeed suggest
preferential protonation to give epimer 11.
15. Pamamycin-607 (1): [h]2D5=+17.8 (c 0.60, CH2Cl2), [h]3D0=
+22.2 (c 0.25, MeOH) (Ref. 1i: [h]3D3=+22.8 (c 0.26,
MeOH)); 13C NMR (125.8 MHz, acetone-d6, excess
CF3CO2D): l 8.66 (q, C-12%), 9.76 (q, C-21), 10.36 (q,
C-20), 13.96 (q, C-18), 14.04 (q, C-19), 14.32 (q, C-11%),
18.76 (t, C-10%), 20.31 (t, C-17), 27.92 (t, C-4%), 28.06 (t,
C-5), 28.97 (t, C-16), 30.02 (t, C-11), 31.13 (t, C-4), 31.54
(t, C-12), 32.11 (t, C-5%), 34.23 (t, C-14), 36.47 (q, NCH3),
37.82 (t, C-9%), 37.85 (d, C-7), 39.41 (t, C-7%), 41.50 (d,
C-9), 42.08 (d, C-2%), 43.71 (q, NCH3), 47.87 (d, C-2),
68.68 (d, C-15), 71.48 (d, C-8%), 75.17 (d, C-6%), 75.22 (d,
C-8), 77.27 (d, C-6), 79.20 (d, C-3%), 79.96 (d, C-13), 81.05
(d, C-10), 83.16 (d, C-3), 173.70 (s, C-1), 174.95 (s, C-1%);
NOESY (500 MHz, acetone-d6, excess CF3CO2D) diag-
nostic NOE’s observed between 19-H and 3-H, 2%-H and
3%-H. 1H and 13C signals were assigned by 2D NMR
(COSY, HSQC, HMBC) spectra and match exactly those
of the natural product 1 separated on an analytical scale
by HPLC from a ca. 1:2 mixture of natural pamamycin-
607 (1) and pamamycin-621A1e,2 kindly provided by Pro-
fessor U. Gra¨fe, Hans-Kno¨ll-Institut fu¨r Naturstoff-
Forschung, Jena.
1
between 2-H and 3-H, 2%-H and 3%-H, 19-H and 20-H. H
and 13C signals were assigned by 2D NMR (COSY,
HSQC, HMBC) spectra.
12. Compound 12: [h]2D5=+8.3 (c 0.40, CH2Cl2); 13C NMR
(125.8 MHz, acetone-d6, excess CF3CO2D): l 7.91 (q,
C-19), 9.61 (q, C-21), 9.98 (q, C-20), 13.98 (q, C-12%),
13.98 (q, C-18), 14.32 (q, C-11%), 18.92 (t, C-10%), 20.34 (t,
C-17), 27.77 (t, C-5), 28.42 (t, C-4), 28.99 (t, C-16), 30.05
(t, C-11), 30.77 (t, C-4%), 31.57 (t, C-12), 31.62 (t, C-5%),
34.41 (t, C-14), 36.60 (q, NCH3), 36.79 (d, C-7), 37.82 (t,
C-9%), 40.88 (t, C-7%), 41.50 (d, C-9), 41.74 (d, C-2), 43.71
(q, NCH3), 49.05 (d, C-2%), 68.60 (d, C-15), 72.30 (d,