2610
V. Badarinarayana, C. J. Lovely / Tetrahedron Letters 48 (2007) 2607–2610
15. (a) Hamada, Y.; Kunimune, I.; Hara, O. Heterocycles
2002, 56, 97; (b) Makino, K.; Hara, O.; Takiguchi, Y.;
Katano, T.; Asakawa, Y.; Hatano, K.; Hamada, Y.
Tetrahedron Lett. 2003, 44, 8925; (c) Hara, O.; Sugimoto,
K.; Makino, K.; Hamada, Y. Synlett 2004, 1625; (d) Hara,
O.; Sugimoto, K.; Hamada, Y. Tetrahedron 2004, 60,
9381.
16. (a) Takeda, Y.; Nakabayashi, T.; Shirai, A.; Fukumoto,
D.; Kiguchi, T.; Naito, T. Tetrahedron Lett. 2004, 45,
3481; (b) Miyata, O.; Shirai, A.; Yoshino, S.; Takeda, Y.;
Sugiura, M.; Naito, T. Synlett 2006, 893, Professor Naito
has informed us that his group has completed an asym-
metric total synthesis of 2.
29. Data for 17: mp = 191–193 °C. [a]D À80.9 (c 0.44,
CHCl3). 1H NMR d = 8.62 (d, J = 9.2 Hz, 1H), 7.61–
7.59 (dd, J = 9.2, 2.0 Hz, 1H), 7.56 (d, J = 2.0 Hz, 1H),
7.25–7.21 (m, 5H), 4.28 (d, J = 12.4 Hz, 1H), 4.05 (ddd,
J = 17.0, 9.6, 8.0 Hz, 1H), 3.16 (d, J = 3.7 Hz, 1H), 3.12
(d, J = 12.4 Hz, 1H), 2.92 (ddd, J = 9.7, 7.0, 3.7 Hz, 1H),
2.65–2.59 (m, 1H), 2.56–2.52 (m, 1H), 2.36–2.34 (m, 1H),
2.22–2.17 (m, 1H), 2.06–2.0 (m, 1H), 1.69–1.57 (m, 3H);
13C NMR d = 174.2, 140.2, 139.6, 137.4, 136.9, 128.4 (2C),
128.3, 127, 126.7 (2C), 121, 85.9, 64, 58.2, 57.2, 51.3, 41.5,
32.3, 24.1, 23.8; FT-IR (KBr, cmÀ1): 2928, 2785, 1693,
1481, 1367. ESI-MS (m/z): 467 (M+Na+, 100), 445
(M+H+, 89), 366 (53), 338 (66), 301 (14), 288 (13), 274
(8). Anal. Calcd for C21H21IN2O: C, 56.77; H, 4.76; N,
6.30. Found: C, 56.60; H, 4.80; N, 6.42.
17. Shaw, J. T.; Masse, C. E.; Ng, P. Y. Org. Lett. 2006, 8,
3999.
18. Ikeda, S.; Shibuya, M.; Iwabuchi, Y. Chem. Commun.
2007, 504.
30. We have demonstrated independently that racemization
does not occur during the cycloaddition through the
preparation of racemic 17 and 18 using the approach
reported by Snider et al.8c starting from the corresponding
iodoanthranilate derivative. Then the 1H NMR spectra of
( )-17 and ( )-18 were recorded in the presence of 2 equiv
of (R)-(+)-2,2,2-trifluoro-1-(9-anthryl)ethanol (Pirkle’s
chiral solvating agent),33 wherein non-equivalence of
several signals was observed. On the other hand, when
(À)-17 and (À)-18 were employed under otherwise iden-
tical conditions, only single absorptions were observed for
the same signals. These experiments unequivocally dem-
onstrate that both the cycloaddition precursors and
adducts are single enantiomers, and by extrapolation so
are subsequent intermediates.
19. Our previously published synthesis introduced the C10–
C12 side-chain after construction of the heterocyclic core
of the molecule using an incipient iminium ion, see Ref.
7d,e. For similar strategies for introduction of the C2 side-
chain see Refs. 17 and 18.
20. (a) Coldham, I.; Hufton, R. Chem. Rev. 2005, 105, 2765;
(b) Pandey, G.; Banerjee, P.; Gadre, S. R. Chem. Rev.
2006, 106, 4484.
21. TPAP, NMO, 4 MS, CH2Cl2, 11%; PCC, CH2Cl2, 0%;
DMSO, (COCl)2, CH2Cl2 then Et3N, 0%; DMSO, DCC,
TFA, pyridine, PhH, 33%; DMP, CH2Cl2, 30%; IBX,
DMSO, 25%; Trichlorocyanuric acid, DMSO then Et3N,
0%; TEMPO, NaOCl, NaBr, PhMe; EtOAc, H2O, 0%.
22. Ackermann, J.; Mathes, M.; Tamm, C. Helv. Chim. Acta
1990, 73, 122.
31. We would like to thank Dr. Hossen Mahmud for
assistance in the preparation of 23. See Ref. 12c.
23. (a) Browning, R. G.; Mahmud, H.; Badarinarayana, V.;
Lovely, C. J. Tetrahedron Lett. 2001, 42, 7155; (b)
Browning, R. G.; Badarinarayana, V.; Mahmud, H.;
Lovely, C. J. Tetrahedron 2004, 60, 359, and references
cited therein.
24. Nair, V.; Richardson, S. G. J. Org. Chem. 1980, 45, 3969.
25. (a) Kwon, T. W.; Keusenkothen, P. F.; Smith, M. B. J.
Org. Chem. 1992, 57, 6169; (b) Keusenkothen, P. F.;
Smith, M. B. J. Chem. Soc., Perkin Trans. 1 1994, 2485.
26. Fleurant, A.; Celerier, J. P.; Lhommet, G. Tetrahedron:
Asymmetry 1992, 3, 695. We are grateful to Professor
Lhommet for providing experimental details.
32. Data for 24: [a]D À95.2 (c 0.58, CHCl3) lit. À94.2 (c 0.28,
CHCl3);12 À179.1 (c 0.80, CHCl3).18 1H NMR (500 MHz,
CDCl3): d = 7.95 (s, 1H), 7.66 (d, J = 8.0 Hz, 1H), 6.60 (d,
J = 8.0 Hz, 1H), 5.29–5.23 (m, 1H), 5.21–5.20 (m, 2H),
3.89 (m, 1H), 3.79 (s, 3H), 3.77–3.74 (m, 2H), 3.43–3.34
(m, 6H), 3.20–3.10 (m, 1H), 2.40–2.32 (m, 1H), 2.08–2.04
(m, 2H), 1.72 (s, 3H), 1.70 (s, 3H), 1.69 (s, 3H), 1.67 (s,
3H), 1.69–1.66 (m, 2H), 1.51 (s, 9H), 1.47 (s, 9H), 1.47–
1.40 (m, 2H); 13C NMR (125 MHz, CDCl3): d = 167.4,
162.2, 159.7, 159.5, 146.5, 137.5, 137.4, 137.2, 131.7, 130.2,
120.2, 119.5, 118.1, 113.9, 82.0, 78.0, 53.8, 51.5, 50.6, 46.9,
43.6, 43.1, 42.6, 39.7, 39.5, 32.0, 30.1, 29.8, 29.5, 28.5, 28.1,
27.9, 26.5, 25.7, 18.1, 14.2, 13.9, 13.3. HR-MS: calcd for
C38H60N7O6 (m/z): 710.4600 (M+H+). Found: 710.4609.
33. (a) Pirkle, W. H.; Sikkenga, D. L. J. Org. Chem. 1977, 42,
1370; (b) Pirkle, W. H.; Adams, P. E. J. Org. Chem. 1978,
43, 378; (c) Pirkle, W. H.; Hauske, J. R. J. Org. Chem.
1977, 42, 2436; (d) Pirkle, W. H.; Hoekstra, M. S. J. Am.
Chem. Soc. 1976, 98, 1832, See also Ref. 23.
27. Arnold, M. A.; Duron, S. G.; Gin, D. Y. J. Am. Chem.
Soc. 2006, 128, 13255.
28. (a) Sharpless, K. B.; Young, M. W. J. Org. Chem. 1975,
40, 947; (b) Grieco, P. A.; Gilman, S.; Nishizawa, M. J.
Org. Chem. 1976, 41, 1485; (c) Grieco, P. A.; Mugio
Nishizawa, M.; Burke, S. D.; Marinovic, N. J. Am. Chem.
Soc. 1976, 98, 1612.