To a mixture of methyl 4-bromo-2-methoxybenzoate (245 mg), (S)-3-benzyloxymethylisothiazolidine 1,1-dioxide (241 mg) described in Preparation Example 1, potassium carbonate (276 mg), potassium iodide (166 mg) and copper(I) iodide (95 mg) were added toluene (3 mL) and N,N′-dimethylethylenediamine (110 μL), and the mixture was stirred with heating under reflux for 8 hr. The reaction mixture was cooled, water was added, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated brine, and the solvent was evaporated. The obtained residue was purified by column chromatography (hexane:ethyl acetate) to give the title compound (380 mg).
