To a suspension of 61.85 g (0.137 mol) of (3-carbomethoxy-1-propyl)triphenylphosphoniumbromide in 290 ml of tetrahydrofurane are added dropwise at 0° C. over argon with stirring, 116 ml (0.116 mol) of 1M solution of potassium tert-butoxide in tetrahydrofurane over a period of 20 min. The mixture is stirred at 0° C. for 1 h and a solution of 29.6 g of (2S,3S,4S)-3-[4-(t-butyldimethylsilyloxy)-2-(3-pyridyl)tetrahydrofuran-3-yl]propanal in 150 ml of tetrahydrofurane is added dropwise over a period of 15 min. The mixture is stirred at room temperature for an additional one h, 50 ml of concentrated aqueous ammonium chloride is added and the mixture is diluted with 2000 ml of ether. The mixture is washed with water and brine and the organic layer is dried (MgSO4) and evaporated. The residue is triturated with ether, the mixture is allowed to stand in the refrigerator overnight and the precipitated triphenylphosphine oxide is filtered and washed with ether. The combined filtrates are evaporated to dryness and the residue is subjected to flash chromatography on silica gel (5×30 cm2) using methylene chloride-ethyl acetate (1:1) as eluent to give 25.8 g of methyl (Z)-(2S,3S,4S)-7-[4-(t-butyldimethylsilyloxy)-2-(3-pyridyl)-tetrahydrofuran-3-yl]-4-heptenoate as an oil with elemental analysis: C,65.55; H,8.95; N,3.18 (theory: C,65.83; H,8.88; N,3.33) and optical rotation [α]D 25=+9.27 (methanol).
