F. Bellina et al. / Tetrahedron Letters 42 (2001) 3851–3854
3853
Me
Me
t-BuO
HO
1) TiCl4 (1.5 eq), CH2Cl2, 0 °C
2) NaCl(aq)
O
O
O
O
(91 % yield)
6c
12
In summary, we have developed an unprecedented,
general and efficient procedure for the regioselective
synthesis of 4-alkyl-3-bromo-2(5H)-furanones 7. We
have also demonstrated that these monobromo deriva-
tives are useful precursors to unsymmetrically substi-
tuted 3,4-dialkyl-2(5H)-furanones which include the
racemic form of naturally occurring seiridin 12.
4. (a) Janini, T. E.; Sampson, P. J. Org. Chem. 1997, 62,
5069–5073; (b) Ref. 1a; (c) Ref. 1e.
5. (a) Bellina, F.; Biagetti, M.; Carpita, A.; Rossi, R. Tetra-
hedron 2001, 57, 2857–2870; (b) Rossi, R.; Bellina, F.;
Catanese, A.; Mannina, L.; Valensin, D. Tetrahedron
2000, 56, 479–487; (c) Bellina, F.; Ciucci, D.; Vergamini,
P.; Rossi, R. Tetrahedron 2000, 56, 2533–2545; (d) Rossi,
R.; Bellina, F.; Biagetti, M; Catanese, A.; Mannina, L.
Tetrahedron Lett. 2000, 41, 5281–5286; (e) Rossi, R.;
Bellina, F.; Biagetti, M.; Mannina, L. Tetrahedron:
Asymmetry 1999, 10, 1163–1172; (f) Rossi, R.; Bellina, F.;
Biagetti, M.; Mannina, L. Tetrahedron Lett. 1998, 39,
7799–7802; (g) Rossi, R.; Bellina, F.; Biagetti, M.; Man-
nina, L. Tetrahedron Lett. 1998, 39, 7599–7602; (h) Rossi,
R.; Bellina, F.; Mannina, L. Tetrahedron Lett. 1998, 39,
3017–3020; (i) Rossi, R.; Bellina, F.; Bechini, C.; Man-
nina, L.; Vergamini, P. Tetrahedron 1998, 54, 135–156.
6. Rossi, R.; Bellina, F.; Raugei, E. Synlett 2000, 1749–
1752.
Acknowledgements
This work was supported by the Ministero dell’Univer-
sita` e della Ricerca Scientifica e Tecnologica (MURST)
and the University of Pisa.
References
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