(2S,3R)-3-benzyloxycarbonylamino-2-hydroxy-4-(4-methylsulfonyl-phenyl)-butanoic acid 、
1-氨基-环丁酸卞酯对甲苯磺酸盐 以
乙醇 为溶剂,
以50%的产率得到1-[(2S,3R)-3-benzyloxycarbonylamino-2-hydroxy-4-(4-methylsulfonyl-phenyl)-butanoyl]-amino-1-cyclobutanecarboxylic acid benzyl ester