Formaldehyde → Methyl 2-(4-chlorophenyl)-3-hydroxypropanoate

To a stirred solution of (4-Chloro-phenyl)-acetic acid methyl ester (2 g, 10.8 mmol) in DMSO (22 mL) was added sodium methoxide (29.2 mg, 0.54 mmol) at 0° C. Paraformaldehyde (342 mg, 11.4 mmol) was then added and the reaction mixture was stirred at room temperature for 4 hours. The reaction mixture was diluted with EtOAc (100 mL), washed with water (3×20 mL), brine (20 mL), dried (Na2SO4) and evaporated in vacuo. The crude material was purified by column chromatography on silica gel (gradient of hexane:EtOAc 100:0 to 84:16) to afford the title compound as a colourless gum in 52% yield, 1.2 g.