[CH3:1][C:2]1([CH3:13])[CH2:12][C:5]2[S:6][C:7]([C:9]([OH:11])=O)=[CH:8][C:4]=2[CH2:3]1.[CH:14]([Mg]Br)=[CH2:15].[ClH:18].CCOCC>C1COCC1>[Cl:18][CH2:14][CH2:15][C:9]([C:7]1[S:6][C:5]2[CH2:12][C:2]([CH3:1])([CH3:13])[CH2:3][C:4]=2[CH:8]=1)=[O:11]A 100-mL single-neck round-bottomed flask equipped with a magnetic stirrer was purged with nitrogen and charged with 113d (2.41 g, 10.0 mmol) and anhydrous THF (20 mL). The solution was cooled to −70° C., and 1 M vinylmagnesium bromide in THF (11 mL, 11.0 mmol) was added with the reaction temperature maintained below −60° C. The reaction mixture was stirred at −13 to −7° C. for 2 h and then warmed to room temperature over 30 min. The reaction was again cooled to −70° C., and a 2 M solution of hydrogen chloride in ether (22.5 ml, 45 mmol) was added. The reaction was then stored in a freezer at −10° C. overnight. After this time the mixture was evaporated under reduced pressure on a rotary evaporator, and the resulting residue partitioned between water (100 mL) and ether (100 mL). The ether extract was dried over sodium sulfate and evaporated under reduced pressure on a rotary evaporator to afford crude 113e (2.86 g, 118%) as a brown oil with approximately 75% purity (by NMR): 1H NMR (300 MHz, CDCl3) δ 7.45 (s, 1H), 3.89 (t, 2H, J=6.9 Hz), 3.30 (t, 2H, J=6.9 Hz), 2.75 (s, 2H), 2.59 (s, 2H), 1.24 (s, 6H)
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