[CH3:1][C@H:2]1[CH:8]=[CH:7][C:6]([S:9][C:10]2[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=2)=[CH:5][CH2:4][C@H:3]1[OH:16].[Li]CCCC.[I-].C[CH:24]=[N+:25]=[CH:26]C.[C:28]([O-])(O)=O.[Na+]>C1COCC1.C(Cl)Cl.CO>[CH3:24][N:25]([CH2:26][C@H:4]1[CH:5]=[C:6]([S:9][C:10]2[CH:11]=[CH:12][CH:13]=[CH:14][CH:15]=2)[CH:7]=[CH:8][C@H:2]([CH3:1])[C@@H:3]1[OH:16])[CH3:28]
A solution of alcohol 29 (80 mg, 0.34 mmol) in THF (4 mL) was cooled to −78° C., and 0.30 mL of n-BuLi (2.5M in hexanes, 0.75 mmol) was added dropwise via syringe. This mixture was brought to −7° C. over 1 h, and stirred at −7° C. for 10 min, then cooled to −78° C., and transferred to a flask containing N,N-dimethylmethyleneammonium iodide (Eschenmoser's salt, 160 mg, 0.86 mmol) in THF (4 mL) via cannula. The resulting suspension was warmed to room temperature over 2 h, then saturated aqueous NaHCO3 (5 mL) was added, the organic layer was separated, and the aqueous layer was extracted with EtOAc (3×5 mL). The combined organic layers were washed with brine, and dried (Na2SO4). Flash column chromatography (CH2Cl2/MeOH; 10:1) afforded 58 mg (58% yield) of 34 as a light yellow oil. 1H NMR (CDCl3, 300 MHz) δ 7.20-7.38 (m, 5H), 6.11 (dd, J=10.5 Hz, 6.3 Hz, 1H), 5.89-5.96 (m, 2H), 4.20 (dd, J=8.4 Hz, 4.2 Hz, 1H), 2.79 (t, J=12.6 Hz, 1H), 2.45-2.55 (m, 3H), 2.31 (s, 6H), 2.24-2.28 (m, 1H), 1.19 (d, J=7.2 Hz, 3H); 13C NMR (CDCl3, 75 MHz) δ 142.0, 135.6, 134.5, 133.7, 130.3, 129.5, 129.1, 126.9, 89.3, 64.9, 45.9, 43.5, 39.4, 23.9, 14.6.
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