To a solution of 2-hydroxy-2-methylpropionic acid (500 mg, 4.80 mmol) in anhydrous tetrahydrofuran (THF, 10 ml) was added sodium hydride (NaH, 60% mineral oil dispersion, 192 mg, 4.80 mmol) batchwise at 5 °C. The reaction mixture was stirred at room temperature for 1 hour. The solvent was removed under reduced pressure and the residue was suspended in anhydrous N,N-dimethylformamide (DMF, 7 ml), followed by the addition of benzyl bromide (821 mg, 4.80 mmol) and a catalytic amount of potassium iodide (KI). The reaction mixture was placed in a microwave reactor and heated at 100 °C for 3 hours. After completion of the reaction, it was cooled to room temperature and the solvent was removed by evaporation under reduced pressure. The residue was dissolved in a solvent mixture of water and ethyl acetate (EtOAc) for partition extraction. The organic phase was separated, washed with saturated saline, dried over anhydrous sodium sulfate, filtered and concentrated to dryness under reduced pressure. The residue was purified by rapid chromatography on silica gel column (eluent: ethyl acetate/petroleum ether=1/1, v/v) to afford benzyl 2-hydroxy-2-methylpropionate as yellow liquid (773 mg, 3.98 mmol, 83% yield).
