The solution CH(CH3)(CO2C2H5)2 of 17.4g dissolved in 75 ml anhydre THF at 0 degree was added the sodium methoxyde of 5.4g in the stirring condition. A clear solution was obtained by adding 12.2g ClCH2CO2C2H5 drop by drop in one hour. The reaction mixture was stirred at room temperature for 24 hours. The formation of the precipition of sodium chloride is filter chloride and THF using a rotary evaporator. The output of the 1,2-2...can reach 96%.