flask is sealed and vacuumed to remove moisture and then filled with nitrogen and then diethylzinc 1 10 ml 1 2 mmol is added therein at room temperature and stirred for two hours s33 the temperature is adjusted to u2212 20 u00b0 c and benzaldehyde 0 11 ml 1 0 mmol is added therein and stirred for 12 hours s34 1n aqueous hcl 1 ml is added into the above solution to terminate the reaction s35 the solution of s34 is extracted with acetyl acetate 20 ml wherein the organic layer is collected and dehydrated with anhydrous mgso 4 and then the mixture is filtered and the filtrate is concentrated by reducing pressure through an air pump to obtain crude product s36 the crude product is purified by column chromatography silica gel eluent is n hexane etoac 10 1 the results are listed in table 1 in which only few values of enantioselectivity are lower than 99 e e when the amount of these ligands is 0 02 additionally when the amount of these ligands is 0 1 all values of enantioselectivity are higher than 99 e e obviously the acylated aminothiol compounds in accordance with the present invention are superior than the catalysts existing in the literature for the asymmetric addition.