2R-hydroxy-3-phenylpropanoic acid benzyl ester as fragment one wassynthesized from D-Phe through diazotization hydrolysis and esterification by benzylalcohol in a yield of 56%;

• 以D-苯丙氨酸为原料,经重氮化水解后用苄酯保护,得到(2R)-羟基苯丙酸苄酯(片断一),两步总收率为56%25。