2-Methyl-3-butyn-2-ol → 2-(1,1-Dimethylprop-2-ynyloxy)propionic acid methyl ester

To a mixture of sodium hydride (23.8 g, 0.595 mol) in tetrahydrofuran (400 ml) cooled to 0° C., is added a solution of 2-methyl-3-butyne-2-ol (50 g, 0.595 mol) in tetrahydrofuran (50 ml). The reaction mixture is stirred at 0° C. for 1 hour. A solution of methyl-2-bromo-propionate (99.36 g, 0.595 mol) in tetrahydrofuran (100 ml) is added to the reaction mixture slowly at 0° C. The reaction mixture is stirred at 0° C. for 2 hours and allowed to come to ambient temperature and stirred for 1 hour. The reaction mixture is cooled to 10° C. and quenched with ice cold water. The mixture is extracted with diethyl ether (3×200 ml), the organic phases are combined, washed with water, and dried over anhydrous sodium sulfate. The mixture is filtered and the filtrate is evaporated under reduced pressure to give 2-(1,1-dimethylprop-2-ynyloxy)propionic acid methyl ester (90 g) as a colorless oil, used without further purification in the next step.