(S)-3-[(R)-2-Azido-but-(E)-ylidene]-4-phenyl-1-((S)-1-phenyl-ethyl)-azetidin-2-one

(R)-(+)-N-苄基-1-苯乙胺

methyl 3-(tert-butoxycarbonylamino)-2-hydroxy-2-methyl-3-phenylpropanoate