2-(4-Bromophenyl)-1,3-dioxolane → 1-[4-(1,3-Dioxolan-2-yl)phenyl]-2-(2-thienyl)ethanone

A 25 ml RB flask with a stirring bar was charged with 1-bromo-4-(1,3-dioxolan-2-yl)benzene (243 mg, 1.0 mmol), followed by anhydrous THF (5 mL). The mixture was cooled to −78° C. and n-butyllithium (687 μL of 1.6 M solution in hexanes) was added dropwise over 2 min. After stirring for 15 min. at −78° C., N-methoxy-N-methyl-2-(2-thienyl)acetamide (1-1) (185 mg, 1 mmol) was added in one portion. After another 30 min at −78° C., the mixture was quenched with sat. ammonium chloride (20 mL), extracted twice with ethyl acetate (10 mL). The combined organic extracts were dried over sodium sulfate, concentrated, and purified via column chromatography over silica gel (0-50% ethyl acetate/hexanes) to give 1-[4-(1,3-dioxolan-2-yl)phenyl]-2-92-thienyl)ethanone (1-2). 1H NMR (CDCl3, ppm) δ: 7.98 (d, J=8.25 Hz, 2H), 7.45 (d, J=8.25 Hz, 2H), 7.15 (d, J=5.15 Hz, 1H), 6.86 (m, 1H), 6.83 (m, 1H), 5.77 (s, 1H), 4.38 (s, 2H), 4.01 (m, 4H).