(1R,2R,4R)-4-(benzenesulfonyl)-N-(cyanomethyl)-2-[(morpholin-4-yl)carbonyl]cyclopentane-1-carboxamide 、
3,3-二氟吡咯烷盐酸 在
N,N-二异丙基乙胺 、
Methanaminium,N-[(dimethylamino)(3H-1,2,3-triazolo[4,5-b]pyridin-3-yloxy)methylene]-N-methyl-, hexafluorophosphate(1-) 作用下,
以
乙腈 为溶剂,
以93%的产率得到(1R,2R)-2-(3,3-Difluoro-pyrrolidine-1-carbonyl)-4-oxo-cyclopentanecarboxylic acid ethyl ester