4030
S. Lang et al. / Tetrahedron Letters 46 (2005) 4027–4030
(50 mL) and washed with water (100 mL), NaHCO3
References and notes
solution (100 mL), 1 M HCl (100 mL) and washed with
brine (100 mL). The organic layer was dried, filtered and
the solvent removed and purified bycolumn chromatog-
raphy(silica: 5–10% EtOAc in heptane) to afford the
desired lactone/lactam.
1. See: Clive, D. L. J.; Wang, J. J. Org. Chem. 2002, 67, 1192,
and extensive references therein.
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Chemistry; Wiley, 2003.
3. See, for example (a) Yorimitsu, H.; Oshima, K. Radicals in
Organic Synthesis; Wiley-VCH, 2000, pp 11–27; (b)
Schaffner, A.-P.; Renaud, P. Eur. J. Org. Chem. 2004,
2291–2298.
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5. (a) Jang, D. O. Tetrahedron Lett. 1996, 37, 5567; (b)
Yorimitsu, H.; Shinokubo, H.; Oshima, K. Bull. Chem.
13. Typical DEPO in organic solvent experimental procedure:
Toluene (10 mL) was boiled for 10 min under nitrogen,
then the substrate [1 equiv (0.04–0.86 mmol)] and DEPO
(10 equiv) were added. VA-501 (0.5 equiv) was added after
5 min and the mixture was heated for 6 h at 80 ꢂC. VA-501
(0.5 equiv) was added again and mixture was further
heated for 6 h. The mixture was cooled and NaOH soln
(2 N, 15 mL) added and then finallythe mixture was
extracted with Et2O (30 mL). The organic layer was dried,
filtered and concentrated in vacuo. The mixture was
purified bycolumn chromatographyon silica gel using
petroleum ether/ethyl acetate (90/10–85/15) to afford the
desired lactone/lactam.
`
Soc. Jpn. 2001, 74, 225; (c) Deprele, S.; Montchamp, J.-L.
J. Org. Chem. 2001, 66, 6745; (d) Yorimitsu, H.;
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H.; Alinejad, A. H.; Hata, K.; Fujioka, H.; Kita, Y.
Tetrahedron Lett. 2004, 45, 8927.
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H.; Oshima, K. Tetrahedron Lett. 1999, 40, 519.
15. For examples of radical-based preparation of eight-mem-
bered rings, see (a) Snider, B. B.; Merritt, J. E. Tetrahe-
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Ikeda, M. J. Chem. Soc., Perkin Trans. 1 1991, 353; (c)
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114, 10981; (d) Molander, G. A.; McKie, J. A. J. Org.
Chem. 1994, 59, 3186; (e) Ghosh, K.; Ghosh, A. K.;
Ghatak, U. R. J. Chem. Soc., Chem. Commun. 1994, 629;
(f) Lee, E.; Yoon, C. H. Tetrahedron Lett. 1996, 37, 5929;
(g) Russell, G. A.; Li, C. Tetrahedron Lett. 1996, 37, 2557;
(h) Chattopadhyay, P.; Mukherjee, M.; Ghosh, S. J.
Chem. Soc., Chem. Commun. 1997, 2139; (i) Lee, E.; Yoon,
C. H.; Lee, T. H.; Kim, S. Y.; Ha, T. J.; Sung, Y.; Park,
S.-H.; Lee, S. J. Am. Chem. Soc. 1998, 120, 7469; (j)
Manzoni, L.; Belvisi, L.; Scolastico, C. Synlett 2000, 1287;
6. Dubert, O.; Gautier, A.; Condamine, E.; Piettre, S. R.
Org. Lett. 2002, 4, 359.
7. (a) Barton, D. H. R.; Jang, D. O.; Jaszberenyi, J. Cs.
Tetrahedron Lett. 1992, 33, 5709; (b) Calderon, J. M. B.;
Chicharro, G. J.; Fiandhorn, R. J.; Huss, S.; Ward, R. A.;
EP 2284 970506, 1997; (c) McCague, R.; Pritchard, R. G.;
Stoodley, R. J.; Williamson, D. S. Chem. Commun. 1998,
2691; (d) Graham, S. R.; Murphy, J. A.; Coates, D.
Tetrahedron Lett. 1999, 40, 2415; (e) Graham, S. R.;
Murphy, J. A.; Kennedy, A. R. J. Chem. Soc., Perkin
Trans. 1 1999, 3071; (f) Kita, Y.; Nambu, H.; Ramesh, N.
G.; Anilkumar, G.; Matsugi, M. Org. Lett. 2001, 3, 1157;
(g) Roy, S. C.; Guin, C.; Kumar, K. K.; Maiti, G.
Tetrahedron 2002, 58, 2435; (h) Jang, D. O.; Cho, D. H.
Tetrahedron Lett. 2002, 43, 5921; (i) Thomson, D. W.;
Commeureuc, A. G. J.; Berlin, S.; Murphy, J. A. Synth.
Commun. 2003, 33, 3631; (j) Caddick, S.; Hamza, D.;
Judd, D. B.; Reich, M. T.; Wadman, S. N.; Wilden, J. D.
Tetrahedron Lett. 2004, 45, 2363; (k) Cho, D. Y.; Jang, D.
O. Synlett 2005, 59, For fuller list of references, see Ref. 9.
8. (a) Barks, J. M.; Gilbert, B. C.; Parsons, A. F.; Upean-
dran, B. Tetrahedron Lett. 2001, 42, 3137; (b) Barks, J. M.;
Gilbert, B. C.; Parsons, A. F.; Upeandran, B. Synlett 2001,
1719; (c) Jessop, C. M.; Parsons, A. F.; Routledge, A.;
Irvine, D. Tetrahedron Lett. 2003, 44, 479; (d) Jessop, C.
M.; Parsons, A. F.; Routledge, A.; Irvine, D. J. Tetra-
hedron: Asymmetry 2003, 14, 2849; (e) Jessop, C. M.;
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Lett. 2004, 45, 5095.
9. Khan, T. A.; Tripoli, R.; Crawford, J. J.; Martin, C. G.;
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11. See however Ref. 15c, which suggests that this is unlikely
for the ester substrates.
12. Typical EPHP experimental procedure: 1-EPHP (3.59 g,
20.0 mmol, 10.0 equiv) and VAZO 88 (196 mg, 0.8 mmol,
0.4 equiv) in drytoluene (10 mL) were added, via a syringe
pump over 10 h, to a stirred solution of substrate
(2.0 mmol, 1 equiv) in drytoluene (200 mL). After addi-
tion was complete, the reaction was left to stir for 1 h. The
reaction was cooled and the solvent was removed under
reduced pressure. The residue was dissolved with EtOAc
´
(k) Monovich, L. G.; Le Huerou, Y.; Ro¨nn, M.;
Molander, G. A. J. Am. Chem. Soc. 2000, 122, 52; (l)
Marco-Contelles, J.; de Opazo, E. Tetrahedron Lett. 2000,
41, 5341; (m) Nandi, A.; Chattopadhyay, P. Tetrahedron
Lett. 2002, 43, 5977; (n) Molander, G. A.; George, K. M.;
Monovich, L. G. J. Org. Chem. 2003, 68, 9533.
16. Typical DEPO in water experimental procedure: Water (3–
4 mL) was boiled for 10 min under nitrogen and then the
substrate [1 equiv (0.04–0.86 mmol)] and DEPO (10 equiv)
were added. VA-501 (0.5 equiv) was added after 5 min and
mixture was heated for 6 h at 80 ꢂC. VA-501 (0.5 equiv)
was added again and mixture was further heated for 6 h.
The mixture was cooled and sodium hydroxide (2 N,
15 mL) was added and then finallythe mixture was
extracted with diethyl ether (20 mL · 3). The organic layer
was dried over anhydrous sodium sulfate, filtered and
concentrated in vacuo. The mixture was purified by
column chromatographyon silica gel using petroleum
ether/EtOAc (90/10–85/15) to afford the desired lactam.
17. (a) Kosugi, M.; Shimizu, Y.; Migita, T. Chem. Lett. 1977,
1423; (b) Stille, J. K. Angew. Chem., Int. Ed. Engl. 1986,
25, 508.
18. Beckwith, A. L. J.; Storey, J. M. D. J. Chem. Soc., Chem.
Commun. 1995, 977.
19. Curran, D. P.; Yu, H. S.; Liu, H. T. Tetrahedron 1994, 50,
7343, and references cited therein.
20. Semi-empirical (AM1) calculations were performed using
SpartanÕ04 for Windows provided byWavefunction Inc.