N-Boc-L-缬氨酸 、
在
N,N-二异丙基乙胺 、 N-[(dimethylamino)-3-oxo-1H-1,2,3-triazolo[4,5-b]pyridin-1-yl-methylene]-N-methylmethanaminium hexafluorophosphate 作用下,
以
乙腈 为溶剂,
以25%的产率得到tert-butyl N-[(1S)-1-[(3aS,6aR)-4-(diethylcarbamoyl)-5-oxo-spiro[2,3,3a,6a-tetrahydropyrrolo[3,2-b]pyrrole-6,1'-cyclobutane]-1-carbonyl]-2-methyl-propyl]carbamate