Br[C:2]1[CH:6]=[CH:5][S:4][CH:3]=1.C([Li])CCC.[CH3:12][CH2:13][CH2:14][CH2:15][CH2:16][CH3:17].[Br-].[Mg+2].[Br-].C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.[O:40]1CCC[CH2:41]1>C1C=CC=CC=1>[S:4]1[CH:5]=[CH:6][CH:2]=[C:3]1[C:14]1[CH:13]=[CH:12][CH:17]=[CH:16][C:15]=1[CH:41]=[O:40]To a solution of 3-bromothiophene (30 mmol) in tetrahydrofuran (20 mL) at -78° C. under nitrogen was added dropwise n-butyllithium in hexane (30 mmol). The mixture was stirred for 45 minutes and magnesium bromide etherate (45 mmol) was added portionwise. The reaction mixture was then allowed to warm to -20° C. over 45 minutes. This mixture was added to a suspension of di-μ-acetato-bis[2-(N-phenylformimidoyl)phenyl]dipalladium (15 mmol) [Onoue et al., J. Organometallic Chem., 43, pp. 431-436 (1972)] and triphenylphosphine (60 mmol) in benzene (250 mL) and the reaction mixture stirred at ambient temperature overnight. The cooled reaction mixture was quenched with 1N hydrochloric acid (175 mL), was stirred for 2.5 hours, filtered, and the phases separated. The aqueous phase was extracted with diethyl ether (2×150 mL) and the combined organic phases were washed with brine and dried over anhydrous sodium sulfate. After filtration, the solvent was removed in vacuo to give an oil which was purified by flash chromatography on silica gel eluted with ethyl acetate:hexane (3:97) to yield Compound 1a as an oil (Rf =0.4).
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