Total Synthesis of Spirotenuipesines A and B concentrated at 30 °C/450 mmHg to remove almost all solvent. The remaining small amount of THF was removed by a short column of SiO2, eluting with 5:1 pentane/Et2O. Fractions were concentrated to remove almost all solvent at 30 °C/450 mmHg. The ﬁnal 2-3 mL solvent was removed by evaporation under N2 stream to give pure, solvent-free epoxide 45, 2.6 g (58% over two steps) as a colorless volatile oil. [R]22.8D +2.7 (c 1.17, CHCl3). 1H NMR (400 MHz, CDCl3): 4.83 (app s, 2H), 3.03 (m, 1H), 2.79 (dd, J ) 4.8, 4.0 Hz, 1H), 2.50 (dd, J ) 2.8, 5.2 Hz, 1H), 2.28 (dd, J ) 15.2, 6.0 Hz, 1H), 2.19 (dd, J ) 15.2, 5.2 Hz, 1H), 1.80 (s, 3H). 13C NMR (100 MHz, CDCl3): 141.2, 112.1, 51.1, 46.9, 40.8, 23.0. MS (APCI+): calcd for C6H11O (M + H) 99.07, found 99.23. (R)-2-Methyl-6-((trimethylsilyl)methyl)hepta-1,6-dien-4-ol. Mag- nesium turnings (1.24 g, 51.8 mmol) were ﬂame-dried under an argon atmosphere. After the mixture was cooled to room temper- ature, THF (5 mL) was added. To this mixture was added 1,2- dibromoethane (50 µ L) to activate the magnesium turnings. Neat 1-bromo-1-trimethylsilylmethylethene (1.0 g, 5.18 mmol) was added slowly (15 min). Reﬂux was maintained for another 30 min. To a cold (-60 °C) solution of epoxide 45 (270 mg, 2.75 mmol) in THF (5 mL) was added copper(I) iodide (74.5 mg, 0.39 mmol). The above Grignard solution in THF was added quickly to the suspension. A THF rinse (3 mL) of the Grignard solution was also added to the suspension. After the reaction was warmed from -60 °C to room temperature over 2 h, the mixture was quenched with aqueous saturated NH4Cl. The mixture was diluted with ether, washed with aqueous saturated NH4Cl and brine, dried over MgSO4, ﬁltered, and concentrated. The residue was puriﬁed by ﬂash chromatography (hexane/ethyl acetate: 12/1) to give the desired product (573 mg, 98%). [R]21.8D +13.5 (c 0.53, CHCl3). 1H NMR (400 MHz, CDCl3): 4.87 (s, 1H), 4.81 (s, 1H), 4.71 (s, 1H), 4.69 (s, 1H), 3.89 (m, 1H), 2.06-2.21 (m, 4H), 1.99 (s, 1H), 1.79 (s, 3H), 1.61 (d, J ) 13.2 Hz, 1H), 1.55 (d, J ) 13.2 Hz, 1H), 0.05 (s, 9H). 13C NMR (100 MHz, CDCl3): 144.5, 142.7, 113.0, 110.1, 66.5, 46.0, 45.5, 26.7, 22.5, -1.5. MS (APCI+): calcd for C12H23OSi (M - H) 211.16, found 211.23. (R)-tert-Butyldimethyl(2-methyl-6-((trimethylsilyl)methyl)hepta- 1,6-dien-4-yloxy)silane (48). To a solution of the above material (124 mg, 0.585 mmol) in 3 mL of DMF were added imidazole (80 mg, 1.17 mmol) and TBSCl (106 mg, 0.70 mmol) at 0 °C. The reaction mixture was allowed to warm to room temperature and stirred overnight. The reaction was quenched with 20 mL of water and extracted with ether (3 × 20 mL). The combined organic phases were washed with water and brine, respectively, dried over MgSO4, and concentrated to give 48 (178 mg, 93%) without further puriﬁcation. [R]21.3D +1.84 (c 1.24, CHCl3). 1H NMR (400 MHz, CDCl3): 4.78 (s, 1H), 4.72 (s, 1H), 4.63 (s, 1H), 4.58 (s, 1H), 3.93 (m, 1H), 2.08-2.24 (m, 4H), 1.74 (s, 3H), 1.55 (d, J ) 13.6 Hz, 1H), 1.51 (d, J ) 13.6 Hz, 1H), 0.89 (s, 9H), 0.05 (s, 6H), 0.02 (s, 9H). 13C NMR (100 MHz, CDCl3): 144.4, 142.9, 113.0, 109.9, 70.0, 46.1, 27.1, 25.9, 23.0, 18.1, -1.1, -1.4, -4.4, -4.5. MS (APCI+): calcd for C18H39OSi2 (M + H) 327.2, found 327.4. (R)-4-(tert-Butyldimethylsilyloxy)-6-methyl-2-methylenehept-6- en-1-ol (10). To a solution of 48 (56 mg, 0.17 mmol) in 3 mL of CH2Cl2 were added PhSeCl (28 mg, 0.143 mmol) and a catalytic amount of SnCl2 at -78 °C. The reaction was stirred at -78 °C for 17 min, warmed to 0 °C, and stirred for another 23 min. After the solvent was removed, the residue was put on a Florisil column for 15 min. The selenide was washed off the column with hexane/ ethyl acetate (10/1). After concentration, the selenide was subse- quently treated with 30% (wt) H2O2 (162 mg, 1.43 mmol) and pyridine (23 µ L) in CH2Cl2 (3 mL) at 0 °C for 20 min. The reaction mixture was quenched with aqueous 20% Na2S2O3, diluted with ether, washed with 20% Na2S2O3, 1 N HCl, aqueous saturated NaHCO3, and brine, dried over MgSO4, ﬁltered, concentrated, and puriﬁed by ﬂash chromatography (hexane/ethyl acetate: 8/1) to give desired product 10 (34 mg, 88% based on PhSeCl or 73% based on 48). [R]23.3D +22.3 (c 0.93, CHCl3). 1H NMR (400 MHz, CDCl3): 5.11 (s, 1H), 4.90 (s, 1H), 4.80 (s, 1H), 4.73 (s, 1H), 4.05 (d, J ) 6.40 Hz, 2H), 3.98 (m, 1H), 2.81 (t, J ) 6.40 Hz, 1H), 2.26 (m, 4H), 1.73 (s, 3H), 0.90 (s, 9H), 0.08 (s, 6H). 13C NMR (100 MHz, CDCl3): 145.6, 142.2, 114.0, 113.3, 70.4, 66.4, 45.2, 41.1, 25.8, 22.8, 18.0, -4.66, -4.71. HRMS (FAB+): calcd for C15H31O2Si 271.2093, found 271.2079. Acknowledgment. We are grateful to the National Institutes of Health (HL25848) for ﬁnancial support of this research. M.D. thanks the generous support from the Guthikonda Fellowship in Organic Chemistry, the Bristol-Myers Squibb Graduate Fellowship in Synthetic Organic Chemistry, and the Sylvia & Victor Fourman Fellowship. We thank Ms. Daniela Buccella (Parkin Group) for the crystal structure analysis and the National Science Foundation (CHE-0619638) for acquisition of an X-ray diffractometer. We thank Ms. Rebecca Wilson for valuable help in editing the manuscript and Prof. Oshima in Tohoku University for generously providing us the natural product spirotenuipesine A for spectra comparison. Supporting Information Available: Experimental proce- dures and characterization for new compounds and crystal- lographic data for compounds 14b and 1a. This material is available free of charge via the Internet at http://pubs.acs.org. JO8016814 J. Org. Chem. Vol. 73, No. 24, 2008 9583