To a solution of 5-fluorobenzo[b]thiophene (1.22 g) in THF (22 ml) was added n-BuLi (1.6 M solution in hexane, 5.0 ml) at −78° C., and the mixture was stirred for 1 hour. To this mixture was added a solution of 3-(1-triphenylmethyl-1H-imidazole-4-yl)propanal (2.93 g) in THF (10 ml), and the mixture was allowed to warm to −40° C. over 1 hour. The mixture was diluted with 10% aqueous ammonium chloride, warmed to room temperature, and extracted with ethyl acetate. The extract was washed with brine, dried over MgSO4, and concentrated. The residue was chromatographed on silica gel using hexane-ethyl acetate (1:1) as an eluent to give the titled compound as colorless crystals (2.58 g).
