To a suspension of sodium hydride 60% dispersion in mineral oil (480 mg, 12 mmol, 1.2 eq.) in THF (20 mL) at 0° C., dimethyl(benzyloxycarbonyl)methyl phosphonate (2.14 ml, 10 mmol, 1.0 eq.) was added dropwise. The mixture was stirred at 0° C. for 15 min. 2-Acetyl pyridine (1.14 mL, 10 mmol, 1.0 eq.) was added dropwise. The mixture was slowly warmed up to r.t. and stirred at r.t. for 18 hours (the ice bath was let expire). The reaction mixture was quenched with sat. aq. NaHCO3 soln. (50 mL). The mixture was extracted with DCM (3×50 mL). The comb. org. phases were washed with sat. aq. NaCl soln., dried over MgSO4, and concentrated in vacuo. The residue was purified by flashmaster (column: 100 g, flow: 45 mL/min, 40 fractions of 45 mL, Heptane 100% to Heptane+40% AcOEt) to yield (E)-3-pyridin-2-yl-but-2-enoic acid benzyl ester as a white solid (LC-MS 3: tR=0.84 min; 254.3) and (Z)-3-pyridin-2-yl-but-2-enoic acid benzyl ester (LC-MS 3: tR=0.63 min; 254.3) as a colorless oil (E/Z ratio ca. 55:13).
