MgSO4. The solvent was removed under reduced pressure. The residue was dissolved in CH2Cl2 (5 mL) at room temperature and treated with 50% mCPBA (50 mg). After stirring for 3 h, the mixture was diluted with CH2Cl2 (15 mL) and washed with 10% aqueous Na2S2O5 solution, brine and the organic phase was dried with anhydrous Na2SO4. After removing the solvent under reduced pressure, the residue was chromatographed on silica gel (petroleum ether:EtOAc, 95:5) to give ent-ambrox (2) (95 mg, 58%, two steps) as colorless crystals; mp. 75-76°C, {lit.21 mp. 69-70o; lit.24 for enantiomer mp. 77-77.5o}; [a] +27.0 (c = 1.0, CHCl20D3), {lit.24 [a] +21.7}; IR (KBr) .20Dmax: 2921, 2869, 2841, 1765, 1456, 1378, 1274, 1218, 1160, 1084, 1068, 1025, 1007, 979, 955, 943 cm-1; 1H NMR (300 MHz, CDCl3) d: 0.84 (3H, s, H-16), 0.85 (3H, s, H-15), 0.88 (3H, s, H-14), 0.94-1.05 (3H, m, H-1, H-2, H-5), 1.10 (3H, s, H-13), 1.36-1.51 (7H, m, H-2, H- 1', H-6, H-7, H-7', H-9, H-11), 1.59-1.79 (3H, m, H-3, H-6', H-11'), 1.92-1.98 (1H, m, H-7), 3.79-3.96 (2H, m, H-12, H-12'); 13C NMR (75 MHz, CDCl3) d: 15.1 (C-16), 18.5 (C-2), 20.7 (C- 6), 21.2 (C-15), 21.2 (C-13), 22.7 (C-11), 33.1 (C-4), 33.6 (C-14), 36.2 (C-10), 39.8 (C-7), 40.0 (C-1), 42.5 (C-3), 57.3 (C-5), 60.1 (C-9), 65.0 (C-12), 79.9 (C-8); MS (m/z) 236 (M+). Anal. Calcd. for C16H28O2: C, 81.29; H, 11.94. Found: C, 81.24; H, 11.65.
Acknowledgements
We thank Dr. C.H. Collins for reviewing this article. We also thank the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) for financial support of this work and a fellowship to RAG.
References and Notes
1. Ohloff, G. The Fragrance of Ambergris. In Fragrance Chemistry, Theimer, E.T., Ed.; Academic Press: New York, 1982, pp 535. 2. Stoll, M.; Hinder, M. Helv. Chim. Acta 1950, 33, 1251 ibid. 1308. 3. Sell, C. Chem. Ind. 1990, 20, 516. 4. For recent publications see: (a) Castro, J.M.; Salido, S.; Altarejos, J.; Nogueras, M.; Sánchez, A. Tetrahedron 2002, 58, 5941; (b) Ishihara, K.; Ishibashi, H.; Yamamoto, H. J. Am. Chem. Soc. 2002, 124, 3647; (c) Bolster, M.G.; Lagnel, B.M.F.; Jansen, B.J.M.; Morin, C.; Groot, A. Tetrahedron 2001, 57, 8369; (d) Moulines, J.; Lamidey, A.M.; Desvergnes-Breuil, V. Synth. Commun. 2001, 749. 5. Zoretic, P.A.; Fang, H.; Ribeiro, A. A. J. Org. Chem. 1998, 63, 4779 and references cited therein. 6. Haksma, A. A. V. H.; Swarts, H. J.; Jansen, B. J. M.; Groot, A. Tetrahedron 1994, 50, 10073. 7. Kutney, J. P.; Chen, Y. H. Can. J. Chem. 1994, 72, 1570. 8. Kutney, J. P.; Cirera, C. Can. J. Chem. 1997, 75, 1136.
