To a suspension of NaH (60%, 884 mg, 22.1 mmol) in dry THF (120 mL) was added ethyl 2-(diethoxyphosphoryl)acetate (4.96 g, 22.1 mmol) at −78° C. After being stirred at −78° C. for 1 hour, a solution of (5-(benzyloxy)-2-methoxyphenyl)(5-methylthiazol-2-yl)methanone (2.50 g, 7.37 mmol) in THF (30 mL) was added drop wise over 30 min. The mixture was stirred at −78° C. for 30 min and then warmed to room temperature with stirring overnight. The mixture was cooled to 0° C. and treated with water (50 mL), pH value was adjusted to 6 with HCl (0.5N). The organic layer was dried over Na2SO4, filtered, and concentrated under reduced pressure. The residue was purified by silica gel chromatography eluting with petroleum ether/EtOAc (3:1) to afford (Z)-ethyl 3-(5-(benzyloxy)-2-methoxyphenyl)-3-(5-methylthiazol-2-yl)acrylate (1.75 g, 58.0%) as yellow gel.
