J. C. Lee, J. K. Cha / Tetrahedron 56 (2000) 10175±10184
10183
(m, 1H); 13C NMR (90 MHz, CDCl3) d 205.4, 170.5, 161.0,
154.6, 152.6, 136.4, 133.2, 132.7, 116.9, 109.2, 91.4, 87.2,
61.2, 61.0, 60.6, 56.0, 55.8, 45.7, 34.5, 30.9, 27.3, 23.5;
HRMS (M1) calcd for C22H27NO7 417.1788, found
417.1799.
K.; Cha, J. K. Org. Lett. 1999, 1, 523. (b) Part 9: Cho, S. Y.; Lee,
J. C.; Cha, J. K. J. Org. Chem. 1999, 64, 3394.
2. For general reviews of 1, see: (a) Wildman, W. C.; Pursey, B. A.
The Alkaloids 1968, 11, 407. (b) Capraro, H.-G.; Brossi, A. The
Â
Alkaloids 1984, 23, 1. (c) Boye, O; Brossi, A. The Alkaloids 1992,
41, 125. (d) Le Hello, C. The Alkaloids 2000, 53, 287.
(S)-7-tert-Butoxycarbonylamino-6,7-dihydro-1,2,3,10-
tetramethoxybenzo[a]heptalene-9(5H)-one (26). Tri-
methylsilyl tri¯ate (0.08 mL, 0.45 mmol) was added drop-
wise at 08C to a solution of 7 (0.014 g, 0.04 mmol) and
triethylamine (0.17 mL, 1.2 mmol) in methylene chloride
(2 mL). After 2 h, saturated aqueous NaHCO3 (5 mL) was
added, and the product was extracted with methylene
chloride (10 mL). The organic extract was dried over
MgSO4, concentrated, and puri®ed by chromatography
(ethyl acetate) to afford 9 mg (62%) of 26 as a white
solid: mp 230±2328C; [a]D2113.48 (c 0.51, CHCl3); IR
3. For a general review of 4±6, see: (a) Buck, K. T. The Alkaloids
1984, 23, 301. For successful total syntheses, see: (b) Banwell,
M. G.; Hamel, E.; Ireland, N. K.; Mackay, M. F. Heterocycles
1994, 39, 205. (c) Banwell, M. G.; Ireland, N. K. J. Chem. Soc.,
Chem. Commun. 1994, 591. (d) Boger, D. L.; Takahashi, K. J. Am.
Chem. Soc. 1995, 117, 12452.
4. (a) Wolff, J.; Capraro, H.-G.; Brossi, A.; Cook, G. H. J. Biol.
Chem. 1980, 255, 7144. (b) Berg, U.; Deinum, J.; Lincoln, P.;
Kvassman, J. Bioorg. Chem. 1991, 19, 53.
5. (a) Schreiber, J.; Leimgruber, W.; Pesaro, M.; Schudel, P.;
Threlfall, T.; Eschenmoser, A. Helv. Chim. Acta 1961, 44, 540.
(b) van Tamelen, E. E.; Spencer, T. A.; Allen, D. S.; Orvis, R. L.
Tetrahedron 1961, 14, 8. (c) Scott, A. I.; McCapra, F.; Buchanan,
R. L.; Day, A. C.; Young, D. W. Tetrahedron 1965, 21, 3605.
(d) Martel, J.; Toromanoff, E.; Huynh, C. J. Org. Chem. 1965,
30, 1752. (e) Kato, M.; Kido, F.; Wu, M. D.; Yoshikoshi, A.
Bull. Chem. Soc. Jpn 1974, 47, 1516. (f) Boger, D. L.; Brotherton,
C. E. J. Am. Chem. Soc. 1986, 108, 6713 and references therein.
6. (a) Nakamura, T.; Murase, Y.; Hayashi, R.; Endo, Y. Chem.
Pharm. Bull. 1962, 10, 281. (b) Woodward, R. B. The Harvey
Lectures Series 59; Academic: New York, 1965; p 31. (as cited
in Fleming, I. Selected Organic Syntheses; Wiley: New York,
1973; pp 202±207) (c) Evans, D. A.; Tanis, S. P.; Hart, D. J.
J. Am. Chem. Soc. 1981, 103, 5813. (d) Banwell, M. G. Pure
Appl. Chem. 1996, 68, 539.
1
(®lm) 3432, 1710, 1625, 1592 cm21; H NMR (360 MHz,
CDCl3) d 7.48 (s, 1H), 7.24 (d, J10.8 Hz, 1H), 6.79 (d,
J10.8 Hz, 1H), 6.52 (s, 1H), 4.98 (d, J6.8 Hz, 1H), 4.45±
4.35 (m, 1H), 3.98 (s, 3H), 3.92 (s, 3H), 3.89 (s, 3H), 3.64 (s,
3H), 2.52±2.47 (m, 1H), 2.38 (dt, J6.8, 12.8 Hz, 1H),
2.31±2.18 (m, 1H), 1.75±1.62 (m, 1H), 1.35 (s, 9H); 13C
NMR (90 MHz, CDCl3) d 179.5, 163.9, 154.3, 153.4, 151.1,
141.6, 136.0, 134.9, 134.2, 131.1, 125.6, 112.0, 107.2, 79.8,
61.4, 61.3, 56.2, 56.0, 53.0, 37.6, 29.9, 29.6, 28.3; HRMS
(M1) calcd for C25H31NO7 457.2101, found 457.2099.
Colchicine (1). A solution of 26 (5 mg, 0.01 mmol) in ether
(1 mL) was treated with 3 mL of 1.0 M solution of hydrogen
chloride in ether. The solution was stirred for 1 h at room
temperature and concentrated under reduced pressure. The
residue was dissolved in ether (3 mL), and 4-(dimethyl-
amino)pyridine (3 mg, 0.02 mmol), triethylamine (0.01
mL, 0.07 mmol) and acetic anhydride (0.01 mL) were
added. The reaction mixture was stirred for 10 h at 258C,
concentrated under reduced pressure, and puri®ed by
chromatography (ethyl acetate) to afford 4 mg (98%) of
colchicine (1) as a white solid: mp 153±1558C; [a]D
2143.58 (c 0.58, CHCl3); IR (®lm) 3279, 3055, 1667,
7. For a preliminary account of part of this work, see: Lee, J. C.;
Jin, S.-j.; Cha, J. K. J. Org. Chem. 1998, 63, 2804.
8. We recently developed a useful variant of employing cyclic
oxyallyls, i.e. oxyallyls embedded in a ring, to broaden the scope
and synthetic utility of the [413] oxyallyl cycloadditions: (a) Jin,
S.-J.; Choi, J.-R.; Oh, J.; Lee, D.; Cha, J. K. J. Am. Chem. Soc.
1995, 117, 10914. (b) Cha, J. K.; Oh, J. Curr. Org. Chem. 1998, 2,
217 and references therein.
1
1620, 1598 cm21; H NMR (360 MHz, CDCl3) d 7.79 (d,
9. For general reviews of oxyallyl cations, see: (a) Noyori, R.;
Hayakawa, Y. Org. React. 1983, 29, 163. (b) Hoffmann, H. M. R.
Angew. Chem., Int. Ed. Engl. 1984, 23, 1. (c) Mann, J. Tetrahedron
1986, 42, 4611. (d) Hosomi, A.; Tominaga, Y. In Comprehensive
Organic Synthesis; Trost, B. M., Fleming, I. Eds.; Pergamon:
Oxford, 1991; Vol. 5, Chapter 5.1. (e) Rigby, J. H.; Pigge, F. C.
Org. React. 1997, 51, 351.
J6.4 Hz, 1H), 7.59 (s, 1H), 7.34 (d, J10.8 Hz, 1H), 6.88
(d, J10.8 Hz, 1H), 6.53 (s, 1H), 4.69±4.62 (dt, J6.4,
12.2 Hz, 1H), 4.01 (s, 3H), 3.94 (s, 3H), 3.90 (s, 3H), 3.65
(s, 3H), 2.55±2.47 (m, 1H), 2.44±2.27 (m, 2H), 1.97 (s, 3H),
1.91±1.80 (m, 1H); 13C NMR (90 MHz, CDCl3) d 179.5,
170.0, 164.0, 153.5, 152.4, 151.2, 141.7, 136.9, 135.6,
134.2, 130.5, 125.6, 112.8, 107.3, 61.6, 61.4, 56.4, 56.1,
52.7, 36.5, 29.9, 22.8; HRMS (M1) calcd for C22H25NO6
399.1682, found 399.1657.
10. Only a handful of reports have been reported for the prepara-
tion a-alkoxy substituted oxyallyl cations: (a) Sasaki, T.; Ishibashi,
È
Y.; Ohno, M. Tetrahedron Lett. 1982, 23, 1693. (b) Fohlisch, B.;
È
Krimmer, D.; Gehrlach, E.; Kashammer, D. Chem. Ber. 1988, 121,
1585. (c) Murray, D. H.; Albizati, K. F. Tetrahedron Lett. 1990, 31,
4109. (d) Stark, C. B. W.; Eggert, U.; Hoffmann, H. M. R. Angew.
Chem., Int. Ed. Engl. 1998, 37, 1266. See also: (e) Harmata, M.;
Jones, D. E. Tetrahedron Lett. 1997, 38, 3861. (f) Harmata, M.;
Jones, D. E.; Kahraman, M.; Sharma, U.; Barnes, C. L.
Tetrahedron Lett. 1999, 40, 1831. For a recent review on hetero-
atom-stabilized allylic cations, see: (g) Harmata, M. Recent
Research Development in Organic Chem. 1997, 1, 523.
Acknowledgements
We are grateful to the National Institutes of Health
(GM35956) for generous ®nancial support.
References
11. a-Sulfur substituted oxyallyl cations are also known: (a)
Harmata, M.; Fletcher, V. R.; Claassen, R. J., II J. Am. Chem.
Soc. 1991, 113, 9861. More recently, the ®rst report on a-nitrogen
substituted oxyallyl cations appeared: (b) Walters, M. A.; Arcand,
1. Part 12 in the series of synthetic studies on [413] cyclo-
additions of oxyallyls. See also: (a) Part 11: Sung, M. J.; Lee,
H. I.; Chong, Y.; Cha, J. K. Org. Lett. in press. (b) Part 10: Lee,