To a solution of 2-(4-adamantan-1-yl-phenoxymethyl)-benzoxazole-5-carboxylic acid methyl ester (100 mg, 0.24 mmol) in dimethyl sulfide (5 ml) and dichloromethane (5 ml) was added aluminum bromide (1.02 g, 3.84 mmol). The reaction mixture was stirred at room temperature for 2.5 h, after which water and 10% HCl were added. After stirring at room temperature for 1 h, the mixture was partitioned between ethyl acetate and water. The organic phase was washed with brine, dried (MgSO4 anh), and concentrated. The residue was purified by silica gel flash column chromatography (CH2Cl2:MeOH=4:1) to give 2-(4-adamantan-1-yl-phenoxymethyl)-benzoxazole-5-carboxylic acid as a white solid (63.8 mg, 66.0% yield).
