Guaiacol → Dimethyl 2-(2-methoxyphenoxy)malonate

2-Methoxy-phenol (guaiacol) (48 ml) was slowly added to a stirred suspension of potassium carbonate (70.8 g) in acetone (480 ml) followed by heating to 45° C. Then, dimethylchloromalonate (63.2 ml) in acetone (50 ml) was added within 20 min. The reaction mixture was heated to reflux for 16 h. The solvent was evaporated under reduced pressure, the residue taken into water and extracted with DCM. The combined organic layers were dried over sodium sulfate and evaporated. The oily product was crystallized from tert.-butyl-methyl-ether. Dimethyl-(o-methoxyphenoxy)malonate (86 g) was obtained.