J. Chem. Research (S), 1997, 33 J. Chem. Research (M), 1997, 0314–0320 The Total Synthesis of Salvinolone Yuan Tian,a Ning Chen,a Hui Wang,a Xin-Fu Pan,*a Xiao-Jiang Haob and Chang-Xiang Chenb aDepartment of Chemistry, National Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000, P. R. China bLaboratory of Phytochemistry, Kunming Institute of Botany, Academia Sinica, Kunming 650204, P. R. China Salvinolone 1 is synthesized in seven steps starting from the readily available enone 3.Based on our previous studies on the syntheses of tricyclic diterpenes we now report the total synthesis of salvinolone 11 which is a natural abietane-type diterpene. As shown in Scheme 1, the known3 enone 3 was methylated by MeLi to afford compound 4 which was reduced by NaBH4 in the presence of CeCl3 .7H2O4 to afford the corresponding unsaturated alcohol 5. Stereoselective cyclization of 5 with a solution of phosphorus pentoxide in methanesulfonic acid5 gave an inseparable mixture of diastereoisomers. A 3 :1 ratio of trans-isomer 6a to cis-isomer 6b was shown in the 1H NMR spectrum.The stereochemistry of the cis-fused AB rings in 6b was indicated by characteristic signals at 0.85 ppm.6 Catalytic hydrogenation of 6 by 5% Pd–C afforded a mixture of 7a and 7b which was directly oxidized with CrO3–HOAc–H2O.7 In this oxidation, the trans-fused 7a was converted into the monoketone 8 and the cis-fused 7b was converted into the diketone 9.Then, 8 was refluxed with DDQ10 in methanol to give a,b-unsaturated ketone 10. Conversion of 10 into the target compound 1 was achieved by deprotection with BBr3.11 Techniques used: IR, 1H NMR, MS, column chromatography, TLC References: 11 Schemes: 3 Received, 19th August 1996; Accepted, 29th October 1996 Paper E/6/05751I References cited in this synopsis 1 L. Z. Lin, G. Blasko and G. A. Cordell, Phytochemistry, 1989, 28, 177. 3 X. L. Wang, Y. X. Cui and X. F. Pan, Tetrahedron Lett., 1994, 35, 423. 4 J. L. Luche, J. Am. Chem. Soc., 1978, 100, 2226. 5 B. W. Axon, B. R. Davis and P. D. Woodgate, J. Chem. Soc., Perkin Trans. 1, 1981, 2956. 6 E. Wenkert, A. Afonso, P. Berk, R. W. J. Carney, P. W. Jeffs and J. D. McChesney, J. Org. Chem., 1965, 30, 713. 7 R. Zhou, X. F. Wang, Y. Tian and X. F. Pan, Chin. Chem. Lett., 1995, 6, 657. 10 J. W. A. Findlay and A. B. Turner, J. Chem. Soc. C, 1971, 547. 11 J. F. Mcomie, M. L. Watts and D. E. West, Tetrahedron, 1968, 24, 2289. J. CHEM. RESEARCH (S), 1996 33 *To receive any correspondence. Scheme 1 Reagents and conditions: i, MeLi (100%); ii, NaBH4, CeCl3.7H2O (80%); iii, P2O5, MeSO3H (95%); iv, H2, 5% Pd–C (100%); v, CrO3–HOAc–H2O (22 and 70%); vi, DDQ, MeOH (87%); vii, BBr3 (33%)