The present invention relates to a process for preparing optically active compounds of formula X and intermediates thereof,wherein the variables of compound of formula X are as defined in the claims and the description.本發明係關於一種用於製備式X之光學活性化合物及其中間物的方法,其中式X化合物之變數係如申請專利範圍及本說明書中所定義。